Chitons (Mollusca: Polyplacophora) - Biological Science - California ...

Volume XLI 

THE FESTIVUS 

A publication of the San Diego Shell Club 

Special Issue 

ISSN 0738-9388 

June 11, 2009 

Chitons (Mollusca: Polyplacophora) 

Known from Benthic Monitoring Programs 

in the Southern California Bight 

Timothy D. Stebbins and Douglas J. Eernisse

COVER PHOTO 

Live specimen of Lepidozona sp. C occurring on a piece of metal debris collected off San Diego, southern California at a depth of 90 m. 

Photo provided courtesy of R. Rowe.

Vol. XLI(6): 2009 THE FESTIVUS Page 53 

CHITONS (MOLLUSCA: POLYPLACOPHORA) KNOWN FROM BENTHIC 

MONITORING PROGRAMS IN THE SOUTHERN CALIFORNIA BIGHT 

TIMOTHY D. STEBBINS 1, * and DOUGLAS J. EERNISSE 2 

1 City of San Diego Marine Biology Laboratory, Metropolitan Wastewater Department, San Diego, CA, USA 

2 Department of Biological Science, California State University, Fullerton, CA, USA 

Abstract: About 36 species of chitons possibly occur at depths greater than 30 m along the continental shelf and 

slope of the Southern California Bight (SCB), although little is known about their distribution or ecology. Nineteen 

species are reported here based on chitons collected as part of long-term, local benthic monitoring programs or less 

frequent region-wide surveys of the entire SCB, and these show little overlap with species that occur at depths 

typically encountered by scuba divers. Most chitons were collected between 30-305 m depths, although records are 

included for a few from slightly shallower waters. Of the two extant chiton lineages, Lepidopleurida is represented 

by Leptochitonidae (2 genera, 3 species), while Chitonida is represented by Ischnochitonidae (2 genera, 6-9 species) 

and Mopaliidae (4 genera, 7 species). The lepidopleurids Leptochiton rugatus and Hanleyella oldroydi are two of the 

most common chitons, accounting for ~35% of all SCB specimens, while a second recognized species of 

Leptochiton, L. nexus, is also reported. Lepidozona (Chitonida: Chitonina: Ischnochitonidae) is the most diverse 

genus in this study, represented by L. golischi, L. mertensii, L. radians, L. retiporosa, L. scrobiculata, and three 

provisional species (Lepidozona spp. A-C). Of these, L. retiporosa and L. scrobiculata are most common, together 

comprising ~29% of the chitons sampled. Callistochiton (Ischnochitonidae) is represented by C. palmulatus. 

Mopaliidae (Chitonida: Acanthochitonina) is represented by Dendrochiton gothicus, D. thamnoporus, Mopalia 

imporcata, M. lowei, M. phorminx, Placiphorella mirabilis, and Tonicella venusta. Details are presented of the 

distribution, abundance, size, and co-occurrence of the observed chiton species, and a key is provided to those 

species expected to live within the studied depths of the SCB. Additionally, several species not collected during this 

study but considered likely to occur or as dubious records are discussed. 

Introduction 

Chitons (Mollusca: Polyplacophora) are a diverse 

and ancient group of marine mollusks, which include 

more than 940 living (Schwabe, 2005; D. J. Eernisse, 

unpublished compilation) and about 430 fossil 

(Puchalsky et al., 2008) recognized species worldwide. 

Although chitons occur from the intertidal to deep ocean 

trenches, most faunal and ecological studies have 

focused on relatively shallow water species. For 

example, the chitons living in intertidal to shallow 

subtidal habitats along the ecologically diverse western 

coast of North America (West Coast) are fairly well 

known, having been covered in a number of regional or 

site specific natural history guides, taxonomic keys, or 

other useful sources (e.g., Burghardt & Burghardt, 

1969; Brusca et al., 1971; Smith, 1975; Allen, 1976; 

Brusca & Brusca, 1978; McLean, 1978; Haderlie & 

Abbott, 1980; Putman, 1980; Kozloff, 1983, 1996; 

O’Clair & O’Clair, 1998; Slieker, 2000; Lamb & 

Hanby, 2005; Eernisse et al., 2007). In contrast, with 

the exception of the preliminary study by Eernisse 

(1998), no studies have specifically addressed the chiton 

fauna occurring at depths > 30 m of this region. This 

cutoff depth is visited only rarely by scuba divers and 

few of the species seen by divers or in the intertidal 

occur below 30 m. 

More than 30 species of chitons representing 15 

genera and six families are likely to occur in waters 

deeper than 30 m along the continental shelf and slope 

*Corresponding author: City of San Diego Marine Biology Laboratory, 2392 Kincaid Road, San Diego, CA 92101-0811, USA. 

E-mail: tstebbins@sandiego.gov

Page 54 THE FESTIVUS VOL. XLI(6): 2009 

of the Southern California Bight (SCB), which ranges 

from Point Conception, California, USA to Cabo 

Colonet, Baja California, México (see Table 1). Except 

for general geographic and bathymetric range 

information listed in monographs and other taxonomic 

works (e.g., Ferreira, 1978, 1979a, 1979b, 1982, 1983; 

Kaas & Van Belle, 1985a, 1985b 1987, 1990, 1994; 

Watters, 1990; Clark, 1994, 1999), little information is 

available concerning the presence of many species in 

these relatively deep southern California waters. Much 

of the shelf and slope benthos of the region is composed 

of soft sediments, which are the focus of several large 

benthic monitoring programs associated with major 

municipal wastewater outfalls (see City of Los Angeles, 

2007, 2008; Orange County Sanitation District, 2007; 

City of San Diego, 2008a, 2008b; Los Angeles County 

Sanitation Districts, 2008). Although soft sediments are 

typically considered unsuitable habitat for chitons, the 

presence of various types of hard substrates scattered 

across the sea floor provides refuges for these animals 

and also exposes them to incidental capture by regular 

benthic or epibenthic sampling activities (e.g., 

Mullineaux, 1987; Eernisse, 1998). In southern 

California, these chiton microhabitats often include 

small rocks, rocky outcroppings or reefs, mollusk shells 

and shell fragments, as well as man-made debris such as 

bottles, cans, and larger pieces of glass, metal, plastic or 

even rubber (TDS, personal observation). This study 

summarizes the SCB benthic chiton fauna collected by 

the above monitoring programs over the past two 

decades or more. 

Methods 

Most of the chitons examined in this study were 

collected as part of the long-term ocean monitoring 

programs conducted by the City of San Diego, City of 

Los Angeles, Los Angeles County Sanitation Districts, 

and Orange County Sanitation District. Additional 

specimens were collected by these or other agencies 

during several large-scale regional monitoring projects 

that spanned the entire SCB. These bight-wide surveys 

included the 1994 Southern California Bight Pilot 

Project (SCBPP) and subsequent Bight’98, Bight’03 and 

Bight’08 regional monitoring efforts in 1998, 2003 and 

2008, respectively (e.g., Bergen et al., 1998, 2001; 

SCBPP, 1998; Ranasinghe et al., 2003, 2007). Samples 

containing chitons were typically collected using 

standard benthic sampling (e.g., Van Veen grabs) or 

trawling (e.g., otter trawl) gear and procedures. It is 

worth noting that this sampling has not targeted rocky 

areas, e.g., using biological (rock) dredge gear, and 

such future sampling could turn up additional chiton 

species. 

All chitons collected were examined and identified 

using dissecting and compound microscopes. Body 

lengths were measured to the nearest 0.1 mm from the 

anterior-most margin of the girdle in front of valve I 

(head valve) to the posterior-most girdle margin behind 

valve VIII (tail valve) with the chitons flattened as much 

as possible. Lengths for excessively curled or damaged 

specimens were estimated. 

Higher-level chiton systematics and phylogeny have 

been in a state of flux and the focus of subsequent 

research for a number of years (e.g., Smith, 1960; Kaas 

& Van Belle, 1980, 1985a, 1985b, 1987, 1990, 1994, 

1998; Van Belle, 1983, 1985, 1999; Eernisse, 1984; 

Sirenko, 1993, 1997, 2006; Buckland-Nicks, 1995, 

2008; Kaas et al., 1998; Okuso et al., 2003). The 

classification expressed in Table 1 follows Eernisse et 

al. (2007), which is supported by recent molecular 

studies by D. J. Eernisse (unpublished; see also 

Eernisse, 2004a, 2004b, 2006, 2007, 2008a, 2008b; 

Kelly & Eernisse, 2008; Vendrasco et al., 2008). This 

arrangement is similar to the recent system proposed by 

Sirenko (2006) but differs in its reassignment of 

Dendrochiton and Tonicella to Mopaliidae Dall, 1889, 

and not Tonicellidae Simroth, 1894, as in Sirenko’s 

classification. Starobogatov & Sirenko (1975) derived 

Tonicellidae from Simroth’s (1894: 321) “Tribus” (= 

tribe) Tonicelloidea without any proposed change in 

composition. Simroth (1894) clearly intended this taxon 

to correspond to one of three “Ischnochitoninae” 

lineages depicted in Pilsbry’s earlier proposed 

phylogeny (reprinted in Simroth, 1894: 326). 

Tonicelloidea as envisioned by Pilsbry and Simroth 

grouped four disparate genera (including Tonicella) 

whose least inclusive grouping would presently 

correspond with Chitonida. In contrast, Sirenko’s (2006) 

composition of Tonicellidae is similar to 

Lepidochitonidae Iredale, 1914, of other authors (e.g., 

Ferreira, 1982, or as subfamily within Ischnochitonidae 

in Kaas & Van Belle, 1985b). We use Lepidochitonidae 

here instead of Tonicellidae because Lepidochitonidae 

sensu Eernisse et al., 2007, is exclusive of Tonicella, 

which instead is considered part of Mopaliidae (see


Table 1. Systematics and bathymetric distribution of chitons likely to occur in waters deeper than 30 m in the 

Southern California Bight (SCB); classification follows Eernisse et al. (2007); * = species reported from SCB benthic 

monitoring programs; † = not included in key; I = intertidal. 

Taxon/Species Depth Range Sources ‡ 

Class Polyplacophora Gray, 1821 

Order Lepidopleurida Thiele, 1910 

Suborder Lepidopleurina Thiele, 1910 

Family Leptochitonidae Dall, 1889 

Hanleyella Sirenko, 1973 

Hanleyella oldroydi (Bartsch MS, Dall, 1919) * 18 - 455 m 7, 10, 13, 24 

Leptochiton Gray, 1847 

Leptochiton americanus Kaas and Van Belle, 1985 400 - 1400 m 13 

Leptochiton cf. belknapi Dall, 1878 160 - 4206 m 15, 19, 23 

Leptochiton nexus Carpenter, 1864 * I - 144 m 7, 10, 13, 24 

Leptochiton rugatus (Carpenter in Pilsbry, 1892) * I - 458 m 7, 10, 13, 24 

Leptochiton sp. * 116 m 23, 24 

Deshayesiella Carpenter MS, Dall, 1879 

Deshayesiella spicata (Berry, 1919) 18 - 467 m 20, 23 

Oldroydia Dall, 1894 

Oldroydia percrassa (Dall, 1894) I - 730 m 7, 10, 13 

Order Chitonida Thiele, 1910 

Suborder Chitonina Thiele, 1910 

Family Chaetopleuridae Plate, 1899 

Chaetopleura Shuttleworth, 1853 

Chaetopleura gemma Carpenter MS, Dall, 1879 I - 50 m 12, 15 

Family Ischnochitonidae Dall, 1889 

Callistochiton Carpenter MS, Dall, 1879 

Callistochiton crassicostatus Pilsbry, 1893 I - 732 m 7, 9, 17, 18 

Callistochiton decoratus Carpenter MS, Pilsbry, 1893 I - 72 m 7, 9, 17, 18 

Callistochiton palmulatus Carpenter MS, Dall, 1879 * I - 85 m 7, 9, 17, 18, 24 

Lepidozona Pilsbry, 1892 

Lepidozona golischi (Berry, 1919) * 75 - 1281 m 1, 2, 7, 24 

Lepidozona mertensii (von Middendorff, 1847) * I - 100 m 7, 8, 15, 24 

Lepidozona radians (Carpenter in Pilsbry, 1892) * I - 150 m 7, 16, 24 

Lepidozona retiporosa (Carpenter, 1864) * I - 1463 m 7, 8, 15, 24 

Lepidozona scabricostata (Carpenter, 1864) † I - 1460 m 7, 8, 15 

Lepidozona scrobiculata (von Middendorff, 1847) * I - 200 m 5, 7, 8, 15, 24 

Lepidozona willetti (Berry, 1917) 13 - 274 m 7, 8, 15 

Lepidozona sp. A * 101 m 24 

Lepidozona sp. B * 305 m 24 

Lepidozona sp. C * 90 m 24 

Stenoplax Carpenter MS, Dall, 1879 

Stenoplax corrugata (Carpenter in Pilsbry, 1892) I - 107 m 15 

Stenosemus von Middendorff, 1847 

Stenosemus stearnsii (Dall, 1902) 412 - 704 m 16 

Suborder Acanthochitonina Bergenhayn, 1930 

Family Acanthochitonidae Pilsbry, 1893 

Acanthochitona Gray, 1821 

Acanthochitona avicula (Carpenter, 1864) I - 36 m 21, 22

Page 56 THE FESTIVUS Vol. XLI(6): 2009 

Table 1 (continued) 

Taxon/Species Depth Range Sources ‡ 

Family Lepidochitonidae Iredale, 1914 

Lepidochitona Gray, 1821 

Lepidochitona beanii Carpenter, 1857 I - 230 m 6, 11, 14 

Family Mopaliidae Dall, 1889 

Dendrochiton Berry, 1911 

Dendrochiton flectens (Carpenter, 1864) I - 38 m 11, 14 

Dendrochiton gothicus (Carpenter, 1864) * I - 230 m 11, 14, 24 

Dendrochiton semiliratus Berry, 1927 38 -141 m 11, 14 

Dendrochiton thamnoporus (Berry, 1911) * I - 38 m 11, 14, 24 

Mopalia Gray, 1847 

Mopalia acuta (Carpenter, 1855) I - 40 m 17 

Mopalia imporcata Carpenter, 1864 * I - 120 m 17, 24 

Mopalia lowei Pilsbry, 1918 * I – 17 m 17, 24 

Mopalia phorminx Berry, 1919 * 18 - 183 m 17, 24 

Placiphorella Carpenter MS, Dall, 1879 

Placiphorella mirabilis Clark, 1994 * 28 - 155 m 3, 17, 24 

Placiphorella pacifica Berry, 1919 155 - 2000 m 3, 17, 23 

Tonicella Carpenter, 1873 

Tonicella venusta Clark, 1999 * I - 140 m 4, 24 

‡ 

Primary sources: (1) Berry, 1919a; (2) Berry, 1925; (3) Clark, 1994; (4) Clark, 1999; (5) Clark, 2004; (6) Eernisse, 

1986; (7) Eernisse, 1998; (8) Ferreira, 1978; (9) Ferreira, 1979a; (10) Ferreira, 1979b; (11) Ferreira, 1982; (12) 

Ferreira, 1983; (13) Kaas & Van Belle, 1985a; (14) Kaas & Van Belle, 1985b; (15) Kaas & Van Belle, 1987; (16) Kaas 

& Van Belle, 1990; (17) Kaas & Van Belle, 1994; (18) Pilsbry, 1892–1893; (19) Schwabe, 2008; (20) Sirenko & 

Clark, 2008; (21) Slieker, 2000; (22) Watters, 1990; (23) R. N. Clark, personal communication; (24) present study.


above). Genera such as Cyanoplax and Nuttallina within 

Lepidochitonidae are common in southern California but 

are not addressed here because they are largely 

restricted to intertidal or shallow subtidal depths. Of the 

taxa considered subfamilies of Ischnochitonidae by Van 

Belle (1983; also Kaas & Van Belle, 1985-1998), we 

follow Eernisse et al. (2007) in considering 

Chaetopleuridae and Lepidochitonidae to be distinct 

from Ischnochitonidae while, unlike Sirenko (2006), we 

retain Callistochiton (part of Van Belle’s 

Callistoplacinae) within Ischnochitonidae. Likewise, we 

recognize the priority of Leptochitonidae Dall, 1889 in 

preference to Lepidopleuridae Pilsbry, 1892, and use it 

to also include Oldroydia and Deshayesiella, not 

separating these genera to Protochitonidae Ashby, 1925, 

as in Sirenko (2006). Based on preliminary molecular 

evidence, it is likely that the monotypic Oldroydia Dall, 

1894, with type species Lepidopleurus (Oldroydia) 

percrassus Dall, 1894 (currently Oldroydia percrassa), 

could eventually be considered a junior synonym of 

Deshayesiella Carpenter MS, Dall, 1879, whose 

members are mostly found in the western Pacific (D. J. 

Eernisse, in preparation). 

Key to Benthic Chitons of the Southern California Bight 

1. Lateral and pleural areas of intermediate valves distinct from jugal region, latero-pleural areas sculptured with 

numerous, elongate, teardrop-shaped pustules, jugum with deeply incised longitudinal striations; girdle with 

sutural tufts of very long, straight, smooth spicules ..................... Acanthochitona avicula 

S Valves not sculptured as above ................................................ 2 

2. Girdle greatly expanded anteriorly, much wider around head valve than tail valve; mouth region with 

conspicuous cephalic lappets extending anteriorly; intermediate valves at least 4 times wider than long, depressed 

in lateral areas .......................................................... 3 

S 

Girdle not expanded anteriorly, equally wide around head and tail valves; mouth region surrounded by simple 

platform, without lappets; intermediate valves less than 4 times as wide as long, with straight or convex lateral 

areas ................................................................ 4 

3. Tegmentum of valves pinkish or greenish grey and streaked or speckled with white, brown or other colors 

...................................................... Placiphorella mirabilis 

S 

Tegmentum of valves colored solid white, although some orange or black deposits may be present 

......................................................Placiphorella pacifica * 

4. Gill rows not separated by interspace, with left and right rows forming a nearly continuous arch surrounding the 

anus; gills merobranchial, restricted to about posterior third of pallial groove; disarticulated valves without 

insertion plates .......................................................... 5 

S 

Gill rows separated by distinct interspace, with left and right rows not reaching the anus; gills holobranchial, 

extending at least half or more the length of the pallial groove; disarticulated valves with insertion plates . 11 

5. Head valve, lateral areas of intermediate valves, and tail valve with randomly arranged, prominent, relatively 

tall tubercles; central areas with longitudinal rows of smaller, flatter pustules; dorsal girdle with tufts of long, 

smooth, calcareous needles up to 400 m long scattered among shorter spicules .... Hanleyella oldroydi 

* Follows R. N. Clark (personal communication) in recognizing Placiphorella pacifica Berry, 1919, as a valid eastern Pacific 

species, although Kaas & Van Belle (1994) consider this a junior synonym of P. atlantica (Verrill & S. I. Smith, 1882).


S 

Valve sculpturing not as above, without prominent tubercles or pustules; girdle with or without long needlelike 

spines, but not usually in dense tufts if present ...................................... 6 

6. Valves heavy with coarse, irregular sculpturing on end valves and latero-pleural areas of intermediate valves; 

jugal region usually distinct, forming a raised and relatively smooth ridge compared to latero-pleural areas; 

posterior edges of intermediate valves curved or distinctly beaked (V-shaped); girdle encroaches conspicuously 

between valves (~50% valve width or more); dorsal girdle surface with scattered smooth, needlelike spicules 

up to 500 m long (may be broken off) ........................................... 7 

S 

Valves thin with mostly fine, granulose sculpturing, with or without raised, round to oval granules; jugum not 

distinct; intermediate valves rectangular with more or less straight posterior edges and small or inconspicuous 

apices; girdle does not encroach noticeably between the valves; girdle with or without long spicules .... 8 

7. Intermediate valves with “a long jugal area characteristically projecting forward for almost half the length of the 

tegmentum” (Sirenko & Clark, 2008: 1) and with a higher “ratio of jugal length to the length of the postmucronal 

area” (Sirenko & Clark, 2008: 4) than in the next choice ....................Oldroydia percrassa 

S 

Intermediate valves “lacking long, distinct and projecting jugal area” (Sirenko & Clark, 2008: 1), with a lower 

“ratio of jugal length to the length of the postmucronal area” (Sirenko & Clark, 2008: 4) than in the previous 

choice .................................................... Deshayesiella spicata 

8. Tegmental sculpture of minute granules forming subgranulose riblets; riblets arranged into radiating series on 

head valve, lateral areas of intermediate valves and postmucronal area of tail valve, and into longitudinal rows 

on central areas and antemucronal area of tail valve ................................... 9 

S Tegmental sculpture roughly granulose, with raised, well separated, round to oval granules ......... 10 

9. Girdle distinctly spiculose, with long needlelike spines to 400 m scattered dorsally amongst mostly short 

(~70 m), oval, smooth spicules; postmucronal slope distinctly concave; black caps of major lateral teeth of 

radula bicuspid, moderately elongate, inner denticle much larger than outer denticle ... Leptochiton nexus 

S 

Girdle not distinctly spiculose, but comprised dorsally of mostly rectangular, ribbed scales not longer than 

~60 m, although longer, ribbed spicules to 140 m are occasionally evident, especially at the valve sutures; 

postmucronal slope generally straight, often vertical in southern California deep-water specimens, with or 

without small depression just below mucro; black caps of major lateral teeth of radula unicuspid, very long and 

sharply pointed ............................................... Leptochiton rugatus 

10. Head valve much smaller than other valves, about one-half the size of tail valve and 70% the width of 

intermediate valves; tegmental sculpture of raised granules organized in chains, arranged longitudinally in central 

areas and more or less radially in lateral areas and on end valves; girdle covered dorsally with mostly blunt, 

striated spicules up to 100 m, and longer, almost smooth needlelike spines up to 375 m along edges of valves; 

black caps of major lateral teeth of radula bicuspid, inner denticle shorter than outer denticle 

..................................................... Leptochiton americanus 

S 

Head valve about as large as tail valve and similar in width to intermediate valves; tegmentum sculptured with 

round granules, arranged quincunxially and not in chains; girdle covered dorsally with elongate, bluntly pointed 

scales or spicules, ~100-150 m long, each scale with 3-4 riblets; black caps of major lateral teeth of radula 

unicuspid, long and sharply pointed ............................ Leptochiton cf. belknapi † 

† Leptochiton cf. belknapi may represent two similar, but distinct nominal species in SCB waters according to R. N. Clark 

(personal communication): L. belknapi Dall, 1878, and L. mesogonus Dall, 1902.


11. Girdle covered dorsally with strongly imbricating oval to nearly rectangular-shaped scales, or conical scale-like 

spicules or corpuscles .....................................................12 

S 

Girdle without imbricating scales or spicules, dorsal surface covered with minute, non-overlapping corpuscles, 

giving a granular or sandy appearance, with or without short pointed spicules, slender spines, dendritic bristles 

or flexible hairs .........................................................25 

12. Head and tail valves with very heavy, prominent ribs ................................ 13 

S 

Head and tail valves without prominent ribs, although there may be distinct radiating rows of globular tubercles 

....................................................................15 

13. Tail valve bulging prominently above other valves, shaped like a fist (may not be developed in small 

specimens), mucro anterior and not raised relative to highly convex postmucronal slope; head valve 

sculptured with about 9 massive, pustulose radial ribs separated by wide sulci, posterior ribs often 

bifurcated; lateral areas of intermediate valves highly raised, sculptured similar to head valve with 2 radial 

ribs separated by narrow groove; girdle covered dorsally with small, oval, imbricating scales (~70 x 130 

m), each with 10-12 fine riblets .............................. Callistochiton palmulatus 

S 

Tail valve not prominently bulging, mucro subcentral to terminal and higher than postmucronal slope; head 

valve with about 7 or 11 radial ribs; girdle scales with 5-8 broad ribs or 10-14 sharp riblets ........14 

14. Mucro high and terminal, postmucronal slope nearly vertical; head valve with about 7 stout ribs separated 

by wide sulci, radial ribs diverging into pustular to scalloped subribs; lateral areas of intermediate valves 

highly raised and sculptured similar to head valve, with single strong radial ridge diverging laterally into 

3-4 subribs; girdle covered dorsally with small, oval, imbricating scales (~90 x 160 m), each with 5-8 

broad ribs ........................................... Callistochiton crassicostatus 

S 

Mucro of intermediate height and subcentral, postmucronal slope straight to slightly convex; head valve with 

about 11 scalloped ribs without subribs, ribs separated by narrow, relatively shallow sulci; lateral areas of 

intermediate valves raised and sculptured similar to head valve with 2 distinct scalloped radial ribs; girdle 

covered dorsally with oval, imbricating scales (~140 x 220 m), each scale with 10-14 sharp riblets 

..................................................... Callistochiton decoratus 

15. Head valve, postmucronal area of tail valve, and raised lateral areas of the intermediate valves with 4-6 

irregular, concentric corrugations; girdle covered dorsally with small, taller than wide (~96 x 72 m), slightly 

bent, ribbed, round-topped scales ................................. Stenoplax corrugata 

S Valves without irregular concentric corrugations, although a few weak growth lines may be present ...16 

16. Imbricating girdle elements juxtaposed, whitish, glossy, much taller than wide (up to 430 x 160 m); 

tegmentum of head valve, lateral areas, and postmucronal area of tail valve sculptured with fine, 

beaded, divaricating radial riblets; apophyses not connected by a jugal lamina (requires disarticulation) 

........................................................ Stenosemus stearnsii 

S 

Girdle elements armor like, consisting of strongly overlapping, usually wider than tall, oval to rectangular 

shaped scales; tegmentum not as above, either smooth with weak granulations or strongly sculptured with various 

types of ridges and/or tubercles; apophyses connected by a jugal lamina that is notched where it connects on each 

side (requires disarticulation) ................................................ 17


17. Tegmentum of all valves appearing almost uniformly smooth with weak, granular sculpturing; color variable, 

often mottled with olive, brown, orange, yellow, or occasionally white; girdle scales approximately rectangular, 

wider than tall (~270 x 170 m), each scale with about 12 fine striations ........ Lepidozona radians 

S 

Tegmentum distinctly sculptured with various combinations and arrangements of raised pustules, tubercles, pits 

and ridges, often arranged in radial or longitudinal rows; head valve, lateral areas of intermediate valves, and 

postmucronal area of tail valve usually similarly sculptured and distinct from central areas ..........18 

18. Central areas of intermediate valves with longitudinal to arching diagonal rows of distinct but shallow pits, 

but without conspicuous longitudinal ridges; end valves and lateral areas of intermediate valves with 

obsolete radial rows of minute, sparsely set, round, usually bead-like tubercles; girdle scales relatively 

small, nearly as tall as wide (~144 x 120 m), with faint longitudinal striations; color often uniform 

brown or reddish-brown and mottled with white in southern California specimens, but also occasionally 

tan or apricot ............................................. Lepidozona retiporosa 

S 

Central areas of intermediate valves with distinct longitudinal ridges that may or may not extend across the 

jugum, sometimes latticed and appearing pitted between; girdle scales usually wider than tall, small (~100 m) 

to large (~450 m), with or without striations, and with or without nipples at top ...............19 

19. Tegmental sculpture of head valve, lateral areas of intermediate valves, and postmucronal area of tail valve 

highly variable, without raised, neatly separated tubercles, but usually with irregular pustules arranged in radial 

ribs, elongated pustules along posterior sutures usually protruding to give a serrated appearance; central areas 

of intermediate valves with well-spaced, longitudinal ridges extending across the jugum, often latticed in 

between; girdle scales rectangular (~180 x 130 m), slightly convex with distinct longitudinal striations; 

tegmentum color variable, usually of greens or browns .................. Lepidozona scrobiculata 

S 

Tegmentum of end valves and lateral areas not as above, sculptured with neatly separated tubercles of various 

sizes and shapes (minute and round, button-like, globular, digitate), sutural ribs not appearing serrated; central 

areas with closely set or well-spaced longitudinal ridges, with or without distinct latticing ...........20 

20. Tegmentum of end valves and lateral areas of intermediate valves sculptured with small, neatly separated, 

roundish (bead-like) tubercles .................................................21 

S 

Tegmentum of valves without small bead-like tubercles, but sculptured with relatively large button-like (flat and 

round), globular or digitate tubercles ............................................22 

21. Tegmentum mostly microgranulose, with sparsely set bead-like tubercles arranged in ill-defined radial 

rows, distance between tubercles at least several times their width (~5 tubercles per row); central areas 

with closely set, often beaded, longitudinal ridges without distinct cross-hatching; girdle scales oval, 

moderately convex, with distinct longitudinal striations; color mostly a uniform orange brown, with or 

without creamy white banding ................................... Lepidozona golischi ‡ 

S 

Tegmentum of end valves and lateral areas sculptured with radiating ribs separated by fine distinct grooves or 

sulci, each rib bearing numerous, closely set bead-like tubercles, distance between tubercles 1-3 times their width 

(~6-12 tubercles per row); central areas with distinct cross-hatching between longitudinal ribs; girdle scales 

strongly convex or bulbous, with faint longitudinal striations, and crowned with a ribbed nipple (often broken 

off) ...................................................... Lepidozona willetti 

‡ Lepidozona golischi formerly synonymized with L. scabricostata (Carpenter, 1864) (see Ferreira, 1978; Kaas & Van Belle, 

1987), but considered in Clark (2008) and herein as a distinct species (L. scabricostata not included in key).


22. Central areas of intermediate valves appearing deeply pitted with longitudinal ridges distinctly cross-hatched; 

tegmentum with widely spaced digitate tubercles or closely set flat or slightly raised round tubercles; girdle scales 

only slightly convex with distinct longitudinal striations ................................23 

S 

Central areas not pitted, without distinct cross-hatching, although faint horizontal latticing may be apparent 

between the prominent longitudinal ridges; tegmental sculpture of closely set, button-like or globular to digitate 

tubercles, distance between tubercles about 1-2 times their width; girdle scales relatively large (>400 m), 

strongly convex, with or without weak striations, and crowned with a ribbed nipple (often broken off) ..24 

23. Tegmentum of end valves and lateral areas of intermediate valves sculptured with radiating rows of wellseparated, 

digitate tubercles, distance between tubercles at least several times their width; tegmentum and girdle 

coloration of banded reddish-browns and tans (color based on single specimen) ....... Lepidozona sp. A 

S 

Tegmentum of end valves and lateral areas sculptured with relatively flat or slightly raised, round, closely set 

tubercles, distance between tubercles about 1-2 times their width; tegmentum and girdle coloration mostly tan 

to light orange with perhaps a darker jugal ridge (color based on single specimen) ..... Lepidozona sp. B 

24. Head valve, lateral areas of intermediate valves, and posterior region of tail valve sculptured with rows of tall, 

globular to sometimes digitate tubercles; longitudinal ridges prominent throughout central areas, clearly 

extending across jugum; girdle scales typically smooth or with nearly obsolete longitudinal striations; color 

generally reddish-brown and blotched with lighter or darker tones ............. Lepidozona mertensii 

S 

Head valve, lateral areas, and posterior region of tail valve sculptured with rows of numerous, flattened, buttonlike 

tubercles; longitudinal ridges of central areas becoming faint or obsolete across the jugum; girdle scales 

usually with faint longitudinal striations apparent; color reddish-brown with white banding on some posterior 

valves (color based on single specimen) ................................. Lepidozona sp. C 

25. Girdle nude dorsally with microscopic elements appearing uniformly granular or sandy, without conspicuous 

spicules, spines, bristles, or hairs ..............................................26 

S 

Girdle with conspicuous dorsal spicules, spines, bristles, or hairs scattered variably over a more or less granular 

or sandy surface ..........................................................27 

26. Central areas of intermediate valves sculptured with 12-16 fine lateral riblets on each side, the 

remainder of the tegmentum evenly microgranulose; tegmentum color variable but mostly greens or reds 

...................................................... Dendrochiton gothicus 

S 

Tegmental sculpture smooth throughout; tegmentum color typically orange or pink, end valves and lateral 

areas with white zigzag lines, pleural areas with 2-5 large white flammules, although colors may be faint 

.......................................................... Tonicella venusta 

27. Girdle beset dorsally with spicules of different sizes and shapes or slender, hyaline spines, without conspicuous 

bristles or hairs ..........................................................28 

S Girdle beset dorsally with dendritic processes, bristles or flexible hairs .......................29 

28. Tegmentum sculptured with conspicuous, raised, spherical tubercles arranged in radiating, branching rows on 

head valve and lateral areas of the intermediate valves, and forming beaded lirae in central areas; girdle covered 

with spicules or spines of different types and sizes (smooth or ribbed, slender or thick, curved or straight); 

tegmental color usually orange, rarely green, often with tiny black pigment spots, tail valve often black and 

spotted with white ........................................... Chaetopleura gemma


S 

Tegmentum smooth to the naked eye, microgranulose, color variable; girdle with long (>500 m), 

slightly curved, slender hyaline spines or spicules interspersed or occurring in bunches of 3-4 at 

sutures ...................................................Lepidochitona beanii 

29. Tegmentum evenly microgranulose, head valve and lateral areas of intermediate valves appearing smooth, central 

areas with or without fine longitudinal riblets .......................................30 

S Tegmentum coarsely sculptured, with or without strong radial, pustulose ribs ..................32 

30. Central areas with longitudinal riblets or grooves; girdle with tufts of plumose setae, with or without stalked 

calcareous processes; setae restricted to sutures only or occurring both near the sutures and as a supramarginal 

row around the girdle ......................................................31 

S 

Central areas smooth, without riblets; girdle without distinct tufts of plumose setae, but with isolated corneous 

setae or hairs up to 1000 m long that bear stalked, calcareous spicules arising from a groove along one side; 

setae located near sutures and around end valves, but not in a supramarginal row .. Dendrochiton flectens 

31. Plumose setae without stalked calcareous spicules, consisting of tufts of long, curved, yellowish hairs 

surrounding a single thicker, branching bristle; setal tufts located near sutures, around the end valves, and as 

a supramarginal row; postmucronal slope concave .................. Dendrochiton thamnoporus 

S 

Plumose setae with stalked calcareous spicules, consisting of tufts of 3-6 fragile, branching, horny 

processes up to 1000 m long; setal tufts present only at the sutures; postmucronal slope straight 

..................................................... Dendrochiton semiliratus 

32. Head valve with 8 weak, thread-like radiating ribs, tegmentum of head valve and lateral areas of intermediate 

valves pitted by oblique, curved decussations, central areas with numerous fine, longitudinal lirae; girdle densely 

covered with small, stout, blunt-topped spicules up to 55 x 14 m, and sparsely scattered long, hollow, grooved 

chitinous setae with 2 series of shorter, stalked, chitinous hairs arising from the grooves. . . Mopalia acuta§ 

S 

Head valve with prominent, annulated to nodulose radial ribs, intermediate valves sculptured similarly with the 

2 heaviest ribs defining the extent of each lateral area; girdle setae not as above ................33 

33. Girdle setae wispy, many as long as the girdle is wide, each with sparse lateral branches; central areas of 

intermediate valves with distinct longitudinal riblets, between which is a dense lattice of irregular, much finer 

lateral subribs; head valve with about 8-10 heavy radiating ribs, interspersed by one or more radiating rows of 

shorter but distinct pustules, similar rows of short pustules between the heavy defining ribs of the lateral areas; 

mucro subcentral .............................................. Mopalia phorminx 

S 

Girdle setae relatively stout, appearing bushy with dense lateral branches, although branching may be less 

pronounced in juveniles; central areas with or without distinct longitudinal riblets; mucro nearly terminal 

....................................................................34 

34. Setae with slender, usually recurved, bristles arranged in numerous indistinct rows, setal shaft visible between 

bristles, bristles angled away from setal shaft at their attachment point; central areas with distinct longitudinal 

riblets, between which are much finer lateral subribs; head valve with about 10 annulated, cordlike, or almost 

smooth radial ribs, lateral areas bounded by similar diagonal and sutural ribs, transverse nodules defining the 

annuli of the radial ribs fused and not separated, interspaces between radial ribs sculptured with mostly 

coalesced granules not arranged in radial rows ....................... Mopalia imporcata 

§Follows Eernisse et al. (2007) in treating Mopalia acuta (Carpenter, 1855) as a somewhat deeper water species distinct from the 

similar M. plumosa Carpenter in Pilsbry, 1893, which was formerly considered a junior synonym of M. acuta.


S 

Setae long, stout and bearing sharply pointed white or yellow tinged spicules that entirely encircle the shaft; 

central areas without distinct longitudinal riblets, appearing pitted with outwardly curving ribbing crossed by 

more or less finer lateral riblets, although some ribbing may appear less curved and more longitudinally 

pronounced in juveniles; head valve with 7-10 coarsely nodulose radial ribs, lateral areas with similar diagonal 

and sutural ribs, nodules distinctly separate, interspaces between heavy ribs of head valve and lateral areas of 

intermediate valves with irregular, radiating rows of elongated granules ............. Mopalia lowei 

Results 

We report 19 species of chitons from mostly deepwater 

habitats ranging throughout the SCB, including 16 

described and three provisional (undescribed) species 

(Table 2). A fourth possible new species is also reported 

based on a single small juvenile. The chitons reported 

were collected between 1988 and 2009 at 66 different 

sampling sites ranging from northern Baja California to 

the northern Channel Islands and Point Conception 

(Figure 1, Appendix A). Several species are distributed 

widely throughout the region, while others are so far 

restricted to one or a few locations. Most individuals 

were collected from depths between 30 and 305 m, 

which were the primary focus of this study. Records for 

a few species collected from slightly shallower waters 

(9-18 m) by SCB benthic monitoring programs are also 

included because we expect these will eventually be 

found in deeper water. As in Eernisse (1998), we found 

the chiton fauna at the depths sampled herein to be 

largely distinct in comparison to the species commonly 

found in either shallower or deeper waters. Information 

is presented below for each species regarding their 

relative abundance, size, geographic distribution, 

bathymetric range, and co-occurrence with other chitons 

in the region. 

Family Leptochitonidae Dall, 1889 

Hanleyella oldroydi (Bartsch MS, Dall, 1919) 

(Plate 1, Figure 2) 

Hanleyella oldroydi is reported to occur along the 

West Coast from Kosciusko Island, Alaska to Cabo San 

Quintin, Baja California at depths ranging from 18 to 

455 m (Ferriera, 1979b; Baxter, 1983; Kaas & Van 

Belle, 1985a; Eernisse, 1998). This species was one of 

the most commonly encountered chitons in the present 

study, occurring in ~22% of the SCB samples 

containing chitons. All H. oldroydi examined in this 

study were collected in deep waters ranging from 50 to 

191 m at sites located off of San Diego, Palos Verdes, 

Santa Monica Bay and the northern Channel Islands. A 

total of 26 specimens of H. oldroydi have been 

examined so far, representing approximately 11% of the 

chitons collected. The maximum length of SCB 

specimens is 7.4 mm (mean = 4.2 mm), which is 

consistent with published records for this small species 

(see Ferreira, 1979b; Kaas & Van Belle, 1985a). 

Hanleyella oldroydi is commonly collected in samples 

with another lepidopleurid, Leptochiton rugatus, 

although the bathymetric range for the latter species 

includes the intertidal (see below). Other chitons 

collected at the same sites include Leptochiton nexus, 

Lepidozona radians, L. mertensii, L. retiporosa, L. 

scrobiculata, and possibly three undescribed species 

(Lepidozona spp. A and C, and Leptochiton sp.). 

Leptochiton nexus Carpenter, 1864 


Leptochiton nexus is known to occur along the West 

Coast from Cohen Island, Alaska to Punta Abreojos, 

Baja California, as well as in the Gulf of California at 

depths ranging from the intertidal to 144 m (Ferriera, 

1979b; Kaas & Van Belle, 1985a). This chiton is 

reported here for the SCB from seven specimens 

collected at six sites located off of San Diego, Palos 

Verdes, Santa Monica Bay and the northern Channel 

Islands at depths of 18-82 m. The maximum length of 

the SCB specimens is 9.3 mm (mean = 5.9 mm), which 

is less than half the size that L. nexus typically reaches 

(see Ferreira, 1979b; Kaas & Van Belle, 1985a). Other 

chitons collected with L. nexus in the present study 

include Hanleyella oldroydi, Leptochiton rugatus, and 

Lepidozona retiporosa. 

Leptochiton rugatus (Carpenter in Pilsbry, 1892) 


Certain recent authors (Ferreira, 1979b; Kaas & 

Van Belle, 1985a) have considered Leptochiton rugatus 

(Carpenter in Pilsbry, 1892) to be widely distributed


Table 2. Summary of chitons collected by benthic monitoring programs in the Southern California Bight (SCB) 

from 1988-2009. 

Species 

Number of 

Specimens 

Number of 

Samples (Sites) 

Body 

Length 

Depth Range of 

SCB Sites 

Leptochitonidae 

Hanleyella oldroydi 26 20 (13) 1 - 7.4 mm 50 - 191 m 

Leptochiton nexus 7 6 (6) 3.5 - 9.3 mm 18 - 82 m 

Leptochiton rugatus 60 33 (23) 1.2 - 8.5 mm 14 - 305 m 

Leptochiton sp. 1 1 3 mm 116 m 

Ischnochitonidae 

Callistochiton palmulatus 2 2 (2) 7 - 13 mm 80 - 85 m 

Lepidozona golischi 3 2 (2) 20.5 - 23 mm 98 - 101 m 

Lepidozona mertensii 3 3 (3) 13 - 15 mm 56 - 85 m 

Lepidozona radians 7 6 (6) 3.8 - 10 mm 9 - 150 m 

Lepidozona retiporosa 46 22 (19) 2.5 - 19 mm 55 - 305 m 

Lepidozona scrobiculata 24 18 (15) 5.8 - 24 mm 14 - 101 m 

Lepidozona sp. A 1 1 12.1 mm 101 m 

Lepidozona sp. B 1 1 13 mm 305 m 

Lepidozona sp. C 1 1 19.5 mm 90 m 

Mopaliidae 

Dendrochiton gothicus 41 5 (1) 1 - 5.5 mm 16 - 18 m 

Dendrochiton thamnoporus 9 5 (5) 1.6 - 9.3 mm 15 - 38 m 

Mopalia imporcata 3 3 (3) 3.5 - 15 mm 38 - 69 m 

Mopalia lowei 1 1 5 mm 17 m 

Mopalia phorminx 2 2 (2) 20 - 24 mm 100 - 130 m 

Placiphorella mirabilis 4 2 (2) 17 - 43 mm 43 - 104 m 

Tonicella venusta 1 1 ~10 mm 15 m


Figure 1. Stations () where chitons have been collected by benthic monitoring programs in the Southern 

California Bight (n = 66; see Appendix A). A few symbols overlap for sites located close together; 3 stations 

of unknown coordinates not shown, including 1 site off Point conception (150 m) and 2 sites off Palos Verdes 

(100 and 130 m).


throughout the North Pacific, occurring in the Sea of 

Japan, the Okhotsk Sea, the Bering Sea, along the West 

Coast from Alaska to Magdalena Bay, Baja California, 

and in the Gulf of California at depths ranging from the 

intertidal to 458 m. Other authors (e.g., Saito, 2000) 

regard the northwestern Pacific Leptochiton assimilis 

(Thiele, 1909) as distinct. Recent molecular studies have 

revealed even further distinctions (D. J. Eernisse and R. 

P. Kelly, unpublished), but based on its nearby type 

locality, those in at least the intertidal to shallow subtidal 

of California are still regarded as L. rugatus, whereas 

the identity of those from deeper water is still somewhat 

uncertain. This deeper water form of L. rugatus is the 

most common and abundant chiton encountered in the 

present study, occurring in ~36% of all samples. 

Specimens of this chiton have been collected at depths 

ranging from 14 to 305 m throughout the SCB, including 

sites located off of San Diego, Palos Verdes, Santa 

Monica Bay, Point Conception and the northern Channel 

Islands. A total of 60 specimens have been examined so 

far, which represents about 25% of the chitons collected 

in the region. SCB benthic specimens of L. rugatus in 

these deeper waters are relatively small with a maximum 

length of 8.5 mm (mean = 3.8 mm), while the 

maximum recorded size for the species is around 16 mm 

(see Ferreira, 1979b; Kaas & Van Belle, 1985a). 

Leptochiton rugatus has been collected with a number of 

other SCB chitons, including especially Hanleyella 

oldroydi and Lepidozona retiporosa. Other chitons that 

co-occurred at sites with Leptochiton rugatus were L. 

nexus and possibly another undescribed species of 

Leptochiton, as well as at least three members of 

Lepidozona: L. radians, L. scrobiculata, and L. sp. B. 

Leptochiton sp. 

We agree with R. N. Clark (personal communication) 

that a single specimen of Leptochiton could be distinct 

from L. rugatus. However, the specimen is small (3 mm 

length) and further work is needed to verify whether this 

chiton actually represents a nominal or new species or is 

merely a somewhat odd juvenile of L. rugatus. This 

specimen was collected at a depth of 116 m at a site 

located north of Point Loma, San Diego where L. 

rugatus and Hanleyella oldroydi also occur. 

Family Ischnochitonidae Dall, 1889 

Callistochiton palmulatus Carpenter MS, Dall, 1879 


Callistochiton palmulatus is reported to occur along 

the West Coast from Mendocino County, northern 

California to San Pablo Point, Baja California at depths 

ranging from the intertidal to 82 m (Pilsbry, 1892-93; 

Ferriera, 1979a; Kaas & Van Belle, 1994; Eernisse, 

1998). This chiton is reported here from two specimens 

collected at separate sites off San Diego at depths of 80- 

85 m, which represents a slight increase in the 

bathymetric range for this species. This chiton has also 

been observed as perhaps the most common chiton 

collected from rock dredges off San Pedro (DJE, 

personal observation), where it is often found inside 

empty mudstone burrows left behind by burrowing 

bivalves (e.g., Adula spp.). The maximum length of the 

SCB specimens is 13 mm (mean = 10 mm), which is 

consistent with published size records for this species 

(see Ferreira, 1979a; Kaas & Van Belle, 1994). Both 

specimens of C. palmulatus reported off San Diego were 

collected along with Lepidozona mertensii. 

Lepidozona golischi (Berry, 1919) 

(Plate 2, Figures 6-7) 

Lepidozona golischi was originally described by Berry 

(1919a) as a member of Ischnochiton based on a 

specimen collected at a depth of 100 fathoms (~183 m) 

off of Santa Monica, California. Ferreira (1978) 

subsequently synonymized L. golischi with Lepidozona 

scabricostata (Carpenter, 1864) in his review of the 

temperate eastern Pacific Lepidozona, and this species 

has since been reported to occur from the intertidal to 

depths of 1460 m along the West Coast from the Gulf of 

Alaska to Sebastian Vizcaino Bay, Baja California (see 

Ferreira, 1978; Baxter, 1983; Kaas & Van Belle, 1987; 

Clark, 1991; Eernisse, 1998). 

Three chitons that fit this general morphology were 

collected in the present study at two sites off San Diego 

at depths of 98-101 m. The maximum length of these 

specimens is 23 mm (mean = 22 mm). Although we at 

first identified these chitons as L. scabricostata, 

comparison with the approximately 7 mm long holotype 

of that species (USNM 16268; see Figure 6a herein) 

revealed significant differences. As also noted by Berry 

(1917) and Ferreira (1978), the central regions of the L. 

scabricostata holotype’s intermediate valves, in 

particular, are very similar to those of L. willetti (not 

reported in this study), even though their girdle scales 

differ substantially. The central areas of these two 

species are alike in their lattice-like sculpturing with 

cross-hatching. In between the left and right central 

areas, the jugal region differs, with longitudinal ribbing


extending across the jugum in L. willetti, whereas the L. 

scabricostata holotype has almost quincunxially 

arranged granules on its jugum without longitudinal 

ribbing. Unlike Ferreira (1978), we also found the 

central regions of the L. scabricostata holotype to differ 

substantially from the lectotype of Ischnochiton (L.) 

golischi (hereafter as L. golischi) at the Santa Barbara 

Museum of Natural History (SBMNH 34395; see Figure 

6b herein), with the longitudinal ribs of L. golischi 

extending across the jugal region similar to L. willetti. 

Unlike either L. willetti or L. scabricostata, the spaces 

between the finely beaded longitudinal ribs of the L. 

golischi lectotype lack strong cross hatching and instead 

have only irregularly scattered granular pustules. Like 

L. willetti, or even more like L. retiporosa (see below), 

the head valve and the lateral areas of the intermediate 

valves of the L. golischi lectotype have radiating rows 

of small, raised and rounded (bead-like) tubercles. In 

contrast, such bead-like tubercles appear lacking in L. 

scabricostata, although this can only be assumed for the 

missing end valves of the holotype. The lateral areas of 

this specimen, however, are quite different from L. 

golischi with small irregular pustules developing along 

the posterior edges that are more similar to that seen in 

L. scrobiculata (see below). Comparison of the three 

San Diego specimens of L. golischi collected as part of 

this study (e.g., Figure 7) with the L. golischi lectotype 

from the SBMNH (Figure 6b) and specimens identified 

as L. scabricostata for the Santa Maria Basin area at 

depths between 75-123 m (see Figures 3.2C-F in 

Eernisse, 1998) confirmed these differences and that 

these chitons are all the same species. Consequently, we 

herein concur with the treatment of Clark (2008: 80-81) 

in resurrecting L. golischi as a distinct species from L. 

scabricostata (Carpenter, 1864). Additional comparisons 

with specimens identified as L. scabricostata collected 

off San Diego at depths between 110-1281 m and 

housed in the Scripps Institution of Oceanography 

Benthic Invertebrate Collection (SIO Cat. Nos. M1208 

and M1389) reveal these chitons to be L. golischi as 

well. Overall, this gives a confirmed depth range for L. 

golischi of 75-1281 m based on the SBMNH type 

material and specimens examined during this study or 

that of Eernisse (1998). Other chitons that co-occured 

with L. golischi in this study were Lepidozona 

retiporosa, L. scrobiculata, and Lepidozona sp. A. 

As mentioned above, L. golsichi also bears similarities 

to another common species of Lepidozona in the SCB, 

L. retiporosa, especially in terms of its sparsely set, 

minute round tubercles on the end valves and lateral 

areas of the intermediate valves. However, L. golischi 

differs markedly in the sculpturing of the central areas, 

especially in its possession of well-separated longitudinal 

riblets that are unlike anything seen in L. retiporosa. 

The above distinctions mostly agree with Clark (2008). 

The one discrepancy, however, is that Clark mentions 

L. golischi as being sculptured with “relatively large, 

often scattered pustules…,” which seems quite different 

from the minute round or bead-like tubercles noted 

herein for this species. 

Finally, besides finding clear differences between the 

primary type material of L. golischi and L. 

scabricostata, we have further considered whether L. 

scabricostata is distinct from other nominal species of 

Lepidozona discussed in this paper, given that the type 

specimen of this species was collected at comparable 

(but slightly shallower) depths off Santa Catalina Island. 

Our suspicion is that the small holotype of L. 

scabricostata (Figure 6a) is merely a juvenile specimen 

of L. scrobiculata, one of the most commonly dredged 

chitons in the SCB. It is our experience that juvenile 

specimens of L. scrobiculata resemble this holotype, 

especially in terms of the small irregular pustules that 

appear to be developing along the posterior edges of the 

intermediate valves. If true, Lepidopleurus scabricostus 

Carpenter, 1864, would then become a junior synonym 

of Chiton scrobiculatus von Middendorff, 1847. 

However, we stop short of proposing such a synonymy 

here, pending more detailed morphological comparisons 

of the holotype of L. scabricostata with confirmed L. 

scrobiculata juveniles. 

Lepidozona mertensii (von Middendorff, 1847) 


Lepidozona mertensii occurs along the West Coast 

from Auke Bay, Alaska to Sacramento Reef, Baja 

California from the intertidal to depths of 100 m 

(Ferreira, 1978; Kaas & Van Belle, 1987). Reports from 

northern Japan waters (Taki, 1938) are doubtful and 

need to be confirmed. This chiton is reported here for 

the SCB from three specimens collected off of San 

Diego and Santa Monica Bay at depths between 56 and 

85 m. The maximum length of the two SCB specimens 

that could be measured is 15 mm (mean = 14 mm), 

while the third individual was broken and disarticulated. 

This overall body size is relatively small for this species, 

which typically reaches lengths ~40 mm and may 

exceed 50 mm in some individuals (see Ferreira, 1978; 

Kaas & Van Belle, 1987). Lepidozona mertensii has 

been found to co-occur with Hanleyella oldroydi, 

Lepidozona retiporosa, and Callistochiton palmulatus in 

the present study.

Page 68 THE FESTIVUS Vol.XLI(6): 2009 

Lepidozona radians (Carpenter in Pilsbry, 1892) 


Lepidozona interstincta (Gould, 1852) (with L. radians 

considered a junior synonym) has been previously 

reported to occur in the Aleutian Islands and along the 

West Coast from Prince William Sound, Alaska to 

Catalina Island, California from the intertidal to depths 

of 72 m (Kaas & Van Belle, 1990). However, Eernisse 

et al. (2007) restored the more commonly used name for 

California specimens, Lepidozona radians (Carpenter in 

Pilsbry, 1892) (formerly Ischnochiton radians), as 

distinct from the more northern L. interstincta. These 

two species are very similar except for range differences, 

coloration, and consistent DNA sequence differences 

(DJE, unpublished data). Lepidozona interstincta, which 

is uniformly tan in color, is probably the only species 

present in Alaska and extends south to at least the 

subtidal of the San Juan Islands, Washington, whereas 

the more variably colored L. radians extends north to at 

least the intertidal of Port Hardy at the northern end of 

Vancouver Island, and south to the intertidal of some 

cold-water upwelling sites south of Ensenada, Baja 

California, México, including new southern range 

extension records near Colonet (DJE, personal 

observation). Lepidozona radians is not generally found 

in the intertidal of southern California but is known from 

seven specimens in the present study collected at depths 

of 9-150 m ranging from northern Baja California to 

Point Conception and the northern Channel Islands. 

These records extend the maximum depth range of this 

species from 72 to 150 m and would be new 

southernmost records except for the previously 

mentioned Baja California specimens. The chitons 

reported here represent two primary color morphs. 

Specimens from off northern Baja and San Diego were 

mottled with olive-green and/or browns (e.g., Figure 

7a), while specimens from off Point Conception and 

Santa Cruz Island were mostly white (e.g., Figure 7b). 

The maximum length of the SCB specimens is 10 mm 

(mean = 7 mm), which is rather small compared to the 

28 mm in length this species or the similar L. interstincta 

may reach (see Kaas & Van Belle, 1990). Other chitons 

that co-occur with L. radians in SCB waters include 

Hanleyella oldroydi, Leptochiton rugatus and Lepidozona 

scrobiculata. 

Lepidozona retiporosa (Carpenter, 1864) 


Lepidozona retiporosa is reported to occur along the 

West Coast from Kosciusko Island, Alaska to the 

southern tip of Baja California from the intertidal to 

depths of 1463 m (Kues, 1974; Ferreira, 1978; Baxter, 

1983; Kaas & Van Belle, 1987; Eernisse, 1998). This 

species represents one of the most common chitons and 

the second most abundant species in the present study, 

occurring in ~24% of the samples and comprising 

~19% of all individuals. A total of 46 L. retiporosa 

were collected at depths ranging from 55 to 305 m at 

sites located off of San Diego, Palos Verdes, Santa 

Monica Bay and the northern Channel Islands. Many 

SCB specimens of L. retiporosa are relatively large with 

a maximum length of 19 mm (mean = 11 mm), while the 

maximum size previously known for this species is 

17 mm (see Ferreira, 1978; Kaas & Van Belle, 1987). 

Lepidozona retiporosa co-occurs with a number of other 

SCB chitons, including Hanleyella oldroydi, Leptochiton 

nexus, L. rugatus, Lepidozona golischi, L. mertensii, L. 

scrobiculata, Lepidozona spp. A, B and C, and Mopalia 

phorminx. 

Lepidozona scrobiculata (von Middendorff, 1847) 


Lepidozona scrobiculata is reported from along the 

West Coast from Sonoma County, California to Thurloe 

Head on the outer coast of Baja California, and its 

vertical distribution extends from the intertidal to depths 

of 200 m (Ferreira, 1978; Kaas & Van Belle, 1987; 

Clark, 2004). The name, L. scrobiculata, which Clark 

(2004) demonstrated was the senior synonym of the name 

used for over 90 years, L. sinudentata (Carpenter in 

Pilsbry, 1892), refers to a highly variable species that is 

one of the most commonly encountered chitons in the 

present study. Specimens of L. scrobiculata occurred in 

~20% of the SCB samples, which were collected at 

depths from 14 to 101 m located off of northern Baja 

California, San Diego, Palos Verdes, Santa Monica Bay, 

and the northern Channel Islands. A total of 24 

specimens of L. scrobiculata were examined, which 

represents about 10% of the chitons collected. The 

maximum length of these specimens is 24 mm (mean = 

13.5 mm), which is nearly as large as the maximum size 

reported for this species (see Ferreira, 1978; Kaas & Van 

Belle, 1987). Lepidozona scrobiculata occurs on a variety 

of substrates (e.g., rocks, metal, plastic and glass debris) 

collected by either benthic grabs or in trawl samples. One 

specimen from off northern Baja was found living 

adjacent to the operculum on the large turban snail 

Megastraea turbanica (Dall, 1910). Many species of 

southern California chitons co-occur with L. 

scrobiculata, including Hanleyella oldroydi, Leptochiton 

rugatus, Lepidozona golischi, L. radians, L. retiporosa,


Lepidozona sp. A, Dendrochiton gothicus, D. 

thamnoporus, Mopalia lowei, and Placiphorella 

mirabilis. 

Lepidozona sp. A 


A presently unidentified 12.1 mm long specimen of 

Lepidozona, referred to herein as Lepidozona sp. A, 

resembles but differs from the more southerly L. 

guadalupensis Ferreira, 1978 (known from Guadalupe 

Island, Baja California) as well as L. mertensii in terms 

of tegmental sculpturing, an opinion that is shared by R. 

N. Clark (personal communication). Lepidozona sp. A 

can be distinguished from these two species by the 

morphology of its girdle scales, which are only slightly 

convex (relatively flat) with each scale bearing about 

eight distinct longitudinal striations or ridges (see Figure 

12e). In contrast, the scales of both L. guadalupensis 

(see Figures 32-33 in Ferreira, 1978) and L. mertensii 

(Figure 8e herein and Figures 20-21 in Ferreira, 1978; 

see also Kaas & Van Belle, 1987) are strongly convex 

or bulbous appearing, often mammillated, and at best 

may appear only weakly striated under normal 

magnification. Furthermore, the impression of striation 

in L. guadalupensis scales is due to rows of minute 

pustules present on their outer surface (see Ferreira, 

1978), which appears unlike anything observed in 

Lepidozona sp. A. This chiton, also appears somewhat 

similar to another provisional species reported in this 

study, Lepidozona sp. B (see below), in terms of the 

distinctly cross-hatched and strongly pitted central areas, 

but may be distinguished from this and other members 

of the genus by the additional combination of characters 

given in the key. Lepidozona sp. A was collected 

southwest of Point Loma, San Diego at a depth of 101 

m. Several other species of Lepidozona were collected 

with this chiton, including L. golischi, L. retiporosa, 

and L. scrobiculata. 

Lepidozona sp. B 


A second unidentified specimen of Lepidozona 

measuring 13 mm in length was collected at a depth of 

305 m at a site located west of Palos Verdes. This chiton 

appears identical with specimens of another unidentified 

Lepidozona collected at a depth of 425 m from the Santa 

Lucia Bank off of San Luis Obispo County north of the 

SCB (R. N. Clark, personal communication). This 

species, referred to here as Lepidozona sp. B, appears 

unique compared to other known West Coast members 

of the genus, from which it can be distinguished by the 

combination of characters given in the key. Although 

this chiton bears some similarity to Lepidozona sp. A in 

the tegmental sculpturing of the central areas (see 

above), these two provisional species can be easily 

distinguished from each other by the morphology of 

their tubercles, which are round and flat or only slightly 

raised in Lepidozona sp. B compared to elongated or 

digitate in Lepidozona sp. A. Other species collected 

with Lepidozona sp. B were Leptochiton rugatus and 

Lepidozona retiporosa. 

Lepidozona sp. C 


A third unidentified specimen of Lepidozona 

measuring 19.5 mm in length was collected at a depth of 

90 m at a site located off San Diego. This chiton, 

referred to here as Lepidozona sp. C, is similar to L. 

mertensii (see above) and L. willetti (not reported in this 

study) in terms of the morphology of the girdle scales, 

which are strongly convex and crowned with a ribbed 

nipple unless broken off. However, the flat button-like 

tubercles of Lepidozona sp. C, which are especially 

prominent on the end valves, are clearly distinct from 

the large, globular to digitate tubercles of L. mertensii 

or the small, bead-like tubercles of L. willetti. 

Lepidozona sp. C also differs from L. willetti in lacking 

distinct narrow sulci that separate the radial rows of 

tubercles on the end valves and lateral areas of the 

intermediate valves. This species also appears similar to 

another undescribed species of Lepidozona reported for 

depths below 10 m ranging from the Cortez Bank, 

southern California to Sacramento Reef, Baja California 

Norte (R. N. Clark, personal communication). Other 

SCB chitons collected with Lepidozona sp. C include 

Hanleyella oldroydi and Lepidozona retiporosa. 

Family Mopaliidae Dall, 1889 

Dendrochiton gothicus (Carpenter, 1864) 


Dendrochiton gothicus is known to occur along the 

western coast and offshore islands of North America 

from Santa Cruz Island, southern California to Isla 

Asunción, Baja California from the intertidal to depths 

of 230 m (Ferreira, 1982; Kaas & Van Belle, 1985b). 

Although often found in deep waters, D. gothicus is 

reported here from only a single monitoring station (5 

samples) in Santa Monica Bay at a depth of 16-18 m. A 

total of 41 specimens of D. gothicus were present in


these samples, however, which accounts for ~17% of 

all chitons examined in this study. The maximum length 

of the SCB specimens is 5.5 mm (mean = 3.4 mm), 

which is about half the size often reached by this small 

species (see Ferreira, 1982; Kaas & Van Belle, 1985b 

as Lepidochitona gothica). In rock dredges off San 

Pedro, this species has normally been found attached to 

coralline algae including juvenile specimens as small as 

about 1 mm in length (DJE, unpublished observation). 

Other chitons that co-occur with D. gothicus include 

Leptochiton nexus, Lepidozona scrobiculata, 

Dendrochiton thamnoporus, and Mopalia lowei. 

Dendrochiton thamnoporus (Berry, 1911) 


Dendrochiton thamnoporus has been previously 

reported to occur from the intertidal to depths of 29 m 

along the western coast and offshore islands of North 

America from Bodega Bay, California to Punta 

Abreojos, Baja California (Ferreira, 1982; Kaas & Van 

Belle, 1985b as Lepidochitona (Dendrochiton) 

thamnopora). This species is reported from nine 

specimens in the present study with a maximum length 

of 9.3 mm (mean = 5.6 mm), which is consistent with 

published records for this small species (see Ferreira, 

1982; Kaas & Van Belle, 1985b). These chitons were 

collected at depths of 15-38 m, which represents a slight 

extension of the depth range for this species, including 

one site off northern Baja California at a depth of 29 m, 

two sites off San Diego at a depths of 27-38 m, one site 

in Santa Monica Bay at a depth of 17 m, and one site 

just off San Miguel Island in the northern Channel 

Islands at a depth of 15 m. The specimen of D. 

thamnoporus from northern Baja was found living on 

the sides of Megastraea turbanica at a site where 

Lepidozona scrobiculata was also collected from another 

individual of this large turban snail. The specimen 

collected near San Miguel Island was found along with 

another chiton, Tonicella venusta, living on a rock 

covered with a flat, encrusting red coralline alga similar 

to Lithothamnion (D. B. Cadien, personal 

communication). Other SCB chitons that occur at the 

same sites with D. thamnoporus include Leptochiton 

nexus, Dendrochiton gothicus, Mopalia imporcata, and 

M. lowei. 

Mopalia imporcata Carpenter, 1864 


Mopalia imporcata is reported to occur along the 

West Coast from Kachemak Bay, Alaska to Punta Santo 

Tomás, Baja California at depths ranging from the 

intertidal to 120 m (Clark, 1991; Kaas & Van Belle, 

1994). This chiton is reported here from three 

individuals, including a tiny juvenile collected at a depth 

of 46 m off of Santa Rosa Island, northwestern Channel 

Islands, and two adults collected off San Diego and Santa 

Monica Bay at depths of 38 and 69 m, respectively. 

These specimens measured 3.5, 13.5 and ~15 mm in 

length, respectively, while the maximum reported size 

for this species is 23 mm (see Kaas & Van Belle, 1994). 

Another species of chiton collected with M. imporcata 

off San Diego was Dendrochiton thamnoporus. 

Mopalia lowei Pilsbry, 1918 


Mopalia lowei is known to occur along the entire 

coast of California at depths ranging from the intertidal 

to shallow subtidal (Kaas & Van Belle, 1994). This 

chiton is reported here from a single specimen collected 

in Santa Monica Bay at a depth of 17 m. The specimen 

was a juvenile with a body length of 5 mm compared to 

a maximum length of 30 mm reported for this species 

(see Kaas & Van Belle, 1994). Other SCB chitons that 

co-occur with M. lowei include Lepidozona scrobiculata 

and Dendrochiton gothicus. 

Mopalia phorminx Berry, 1919 


Mopalia phorminx is considered a rather 

uncommon chiton with a reported distribution along the 

West Coast ranging from Prince William Sound, Alaska 

to San Pedro, California at depths ranging from 18 to 

183 m (Clark, 1991; Kaas & Van Belle, 1994). This 

chiton is reported here from two specimens collected at 

separate sites off Palos Verdes at depths of 100 and 

130 m, although the exact locations of these sites are 

currently unknown (D. B. Cadien, personal 

communication). The maximum length of the SCB 

specimens is 24 mm (mean = 22 mm), which is 

relatively large for this species (see Kaas & Van Belle, 

1994). This species co-occurs with Lepidozona 

retiporosa. 

Placiphorella mirabilis Clark, 1994 


Placiphorella mirabilis occurs from Santa Barbara, 

southern California to Isla Cedros, Baja California at 

depths of 28-155 m (Clark, 1994; Kaas & Van Belle, 

1994, as Placiphorella species 1). This species is known


from a total of four specimens in the present study that 

were collected during trawls conducted as part of the 

Southern California Bight Pilot Project in 1994. These 

chitons occurred at two different sites off San Diego, 

which ranged in depth from 43 to 104 m. The maximum 

length of the SCB specimens of P. mirabilis is 43 mm 

(mean = 24.5 mm), which is rather large compared to 

previous records for this species (see Clark, 1994). 

Another chiton found with P. mirabilis was Lepidozona 

scrobiculata. 

Tonicella venusta Clark, 1999 


Tonicella venusta occurs along the West Coast 

from south-central Alaska to Isla Cedros, Baja 

California from the intertidal to depths of 140 m (Clark, 

1999). This chiton is reported here from a single 

specimen collected at a depth of 15 m just off of San 

Miguel Island, the westernmost of the northern Channel 

Islands. It should be noted that this island has a chiton 

fauna that is more normally typical of central California, 

not southern California. The chiton was curled with an 

estimated length of ~10 mm, which is consistent with 

published size records for this species (see Clark, 1999). 

This specimen of T. venusta was found living with 

Dendrochiton thamnoporus on a rock covered with a 

flat, encrusting red coralline alga (~Lithothamnion) that 

was brought up in the jaws of a benthic grab (D. B. 

Cadien, personal communication). 

Discussion 

The present study brings to 16 the number of 

described chiton species known to occur along the 

continental shelf and upper slope of the Southern 

California Bight (SCB) in waters mostly deeper than 30 m 

based on collections provided by benthic monitoring 

programs in the region, plus three provisional species as 

well as a fourth possibly undescribed species (see Tables 

1 and 2). Of the two extant chiton lineages, 

Lepidopleurida is represented only by Leptochitonidae 

(3 species), while Chitonida is represented by Chitonina: 

Ischnochitonidae (6 described and 3 provisional species) 

and Acanthochitonina: Mopaliidae (7 species). 

Seventeen other species are also likely to occur based on 

published bathymetric and geographic distributions (see 

Table 1 and below), which brings the region’s estimated 

chiton fauna for these deeper waters to about 36 species. 

In contrast, Eernisse (1998) reported only six species in 

material collected in a survey of relatively deep waters 

(50-250 m) of the Santa Maria Basin and Western Santa 

Barbara Channel (all also sampled here), but he 

cautioned that these were limited samples with at least 

another 13 species likely to occur in the region (i.e., 19 

species total), probably living in rockier bottoms than 

generally sampled in this study. 

It is notable that although the total number of 

chiton species is relatively high in the SCB benthos, 

only three of about 12 total extant taxa typically ranked 

at a family level worldwide are present and the diversity 

of genera within these three families is not impressive. 

The genera that are most diverse are also the most 

diverse in the northern Pacific. This is similar to chitons 

living in shallow waters along the West Coast, where 

higher-level taxonomic diversity is low but certain 

genera (e.g., Cyanoplax, Lepidozona, Mopalia, Tonicella) 

are either exclusively northern Pacific or else are by far 

most diverse there. Our review thus supports the general 

pattern that both the shallow and moderately deep fauna 

of the northern Pacific has both a high degree of 

endemism, with relatively few higher taxa present, but 

those taxa that are present are impressively species-rich. 

The general lack of overlap between the chiton 

fauna above or below about 30 m depth has implications 

for the extent of population connectivity of cooler water 

“northern” species that so far have not been reported in 

shallow water off southern California. These have been 

found in shallow water from especially the coolest sides 

of the northern and western Channel Islands, and also 

from the intertidal of known upwelling sites south of 

Punta Banda, northern Baja California, in the 

southernmost SCB. Are these apparently disjunct 

populations actually connected to central California 

through individuals living at depths > 30 m off 

mainland southern California? Our results suggest not. 

Assuming that these species have not merely been 

overlooked in shallower water along southern California 

shores, we propose that it is more likely that population 

connectivity, if it occurs at all, must be the result of 

relatively long-distance dispersion of larvae from central 

California. Given the predominantly warm nature of any 

return currents to central California via the Davidson 

countercurrent, and the relatively rare occurrence of such 

southern “refugia,” it could be much less likely that 

planktonic larvae from southern disjunct “cool water” 

populations could be expected to recruit back to central 

California. The existence of such “peripheral isolate” 

shallow water southern populations could reflect ongoing 

processes of genetic isolation that could be producing 

incipient species. This opportunity for speciation, 

combined with climate-related latitudinal shifts over 

geological time, could help explain the high diversity of 

certain species-rich genera in the shallow waters of the


cool temperate West Coast. Most previous emphasis in 

the literature has been on the parallel situation of 

northern refuge populations of warm temperate species 

in the anomalously warm parts of central California, 

such as Monterey Bay. This latter well-documented 

pattern of northern refugia is probably most important 

for taxa extending north from the warmer latitudes, 

whereas southern refugia are probably more important 

to those taxa whose primary diversification has been in 

the cool northern Pacific (e.g., Kelly & Eernisse, 

2008). 

Two of the four most widely distributed and 

abundant chitons encountered in this study are 

lepidopleurids of the family Leptochitonidae; each 

occurred in at least 22% of the samples. These 

common species include Leptochiton rugatus (Figure 4) 

and Hanleyella oldroydi (Figure 2), which together 

comprised more than 35% of the chitons examined. As 

mentioned previously, a new study (Eernisse & Kelly, 

unpublished) has provided DNA-based evidence that 

what we have referred to as L. rugatus is actually an 

undescribed deep-water species, which is part of a 

complex of northern Pacific species related to the 

“true” L. rugatus of shallow waters. A second 

Leptochiton species, L. nexus (Figure 3), is reported 

from several specimens, while a third and possibly new 

species of Leptochiton is known from a single small 

individual. At least two other species of Leptochiton 

that are presently known from only depths of 160 m or 

below, L. americanus and L. cf. belknapi, could also 

occur along the SCB continental shelf and slope (see 

Ferreira, 1979b; Wu & Okutani, 1984; Kaas & Van 

Belle, 1985a, 1987; Schwabe, 2008; also R. N. Clark, 

personal communication). Multiple specimens of 

another lepidopleurid, all identified as Oldroydia 

percrassa, have been regularly collected in rock dredge 

samples taken off southern California (DJE, personal 

observation). Their identities need to be reevaluated in 

light of Sirenko & Clark’s (2008) recent revival of the 

similar Deshayesiella spicata (Berry, 1919) from off 

San Diego and elsewhere along the West Coast (see 

below and also Kaas & Van Belle, 1985a). 

Chitonina: Ischnochitonidae is represented by 

Lepidozona and Callistochiton. Lepidozona is the most 

diverse of the SCB chiton genera that occur at depths 

below 30 m, being represented here by five described 

species, including L. golischi, L. mertensii, L. radians, 

L. retiporosa, and L. scrobiculata (Figures 6-11). Of 

these, L. retiporosa and L. scrobiculata are the most 

common species, with each occurring in at least 20% 

of the samples and together accounting for about 29% 

of the chitons examined. Additionally, three likely new 

species of this genus, herein designated Lepidozona 

spp. A, B and C, are reported (Figures 12-14). The 

genus Callistochiton is represented by a single species, 

C. palmulatus (Figure 5), which is known from two 

records in the present study. However, this species is 

probably much more common in deeper SCB waters 

than indicated here, having frequently been observed to 

live in vacant mussel bore holes in soft mudstone 

collected off San Pedro, Los Angeles County (DJE, 

personal observation). Two other species of 

Callistochiton, C. crassicostatus and C. decoratus, may 

also occur in deep water habitats of the region (see 

Ferreira, 1979a; Kaas & Van Belle, 1994; also see 

below). Endnote Additional genera and species of 

Chitonina that may occur in the SCB at the depths 

sampled in this study are Chaetopleura gemma, 

Stenoplax corrugata (see below), and Stenosemus 

stearnsii (see Ferreira, 1983; Kaas & Van Belle, 1987, 

1990). 

Acanthochitonina: Mopaliidae is represented by 

four genera with seven species. These include 

Dendrochiton gothicus and D. thamnoporus (Figures 

15-16), Mopalia imporcata, M. lowei and M. phorminx 

(Figures 17-19), Placiphorella mirabilis (Figure 20), 

and Tonicella venusta (Figure 21). Each of these 

species occurred in no more than five samples in this 

study and, with the exception of D. gothicus, was 

represented by at most a few individuals. Additional 

Acanthochitonina species likely to occur in relatively 

deep waters of the region include Acanthochitona 

avicula within Acanthochitonidae, Lepidochitona beanii 

within Lepidochitonidae, and Mopalia acuta, 

Dendrochiton flectens, D. semiliratus and Placiphorella 

pacifica within Mopaliidae (e.g., Ferreira, 1982; Kaas 

& Van Belle, 1985b, 1994; Eernisse, 1986; Watters, 

1990; Clark, 1994). Another species within Mopaliidae, 

Katharina tunicata, has also long been reported to 

range as far south as Santa Catalina Island and the 

Coronado Islands, and to occasionally reach depths 

down to 40 m (e.g., Pilsbry, 1893; Oldroyd, 1927; 

Ricketts et al., 1985; Kaas & Van Belle, 1994). We do 

not include K. tunicata as part of the SCB benthic fauna 

discussed herein as we consider this normally intertidal 

chiton unlikely to occur in any subtidal samples from > 

30 m depth. Additionally, aside from its presence in 

fossil deposits near San Pedro (see Berry, 1922), we 

have been unable to verify any records of the species 

south of San Luis Obispo County in central California. 

Two additional chitons have been recorded 

previously from monitoring activities in the region, but 

are considered dubious records and are not included 

here as part of the SCB fauna. These include the 

lepidopleurid, Hanleya hanleyi, and an unidentified 

species of Ischnochiton (i.e., Ischnochiton sp. in


SCAMIT, 1994, 1996). 

The H. hanleyi record was based on a single chiton 

collected off Point Conception in 1977 by the Southern 

California Coastal Water Research Project (SCCWRP). 

Unfortunately, the specimen was disposed of long ago (D. 

Tsukada, personal communication), and therefore the 

identification could not be verified. However, we agree 

with Ferreira (1979b) that Hanleya is not present in 

Pacific waters, or at least not in the eastern Pacific. 

Ferreira attributed previous eastern Pacific references to 

H. hanleyi by Oldroyd (1927), Smith (1947a, 1947b), 

Smith & Gordon (1948), and Jakovleva (1952) as 

probable misidentifications of juvenile Oldroydia 

percrassa (Dall, 1894). We agree that this is a good 

possibility, but it might alternatively be the nominal 

species that Sirenko & Clark (2008) have recently 

revived, Deshayesiella spicata (Berry, 1919). These 

authors regard D. spicata to be highly similar to O. 

percrassa but with a less conspicuously elevated jugal 

ridge and less projecting jugal articulamentum (the latter 

seen only in disarticulated valves). Deshayesiella spicata 

was first proposed as Hanleya spicata by Berry (1919b) 

and we have included it in our key, directly quoting their 

(Sirenko & Clark, 2008) primary distinctions between 

these nominal species. The contrast is complicated by the 

small size (4.5 mm length) of the holotype of D. spicata 

and the fact that this holotype has not yet been contrasted 

with typical O. percrassa of a similar size. It remains to 

be seen whether future studies will confirm these as 

distinct species or find instead that the differences reflect 

intraspecific variation, perhaps due to microhabitat 

differences experienced by the chitons. Larger “spicata” 

specimens similar to those described by Sirenko & Clark 

(2008) have been observed by one of us (DJE), taken by 

rock dredges off San Pedro in Los Angeles County, 

whereas several typical specimens of O. percrassa have 

been observed from slightly shallower depths off Point 

Loma in San Diego County (see below) and from the 

subtidal of Monterey County, central California (A. 

Draeger, personal communication). A third possibility is 

that the “Hanleya hanleyi” animal was a misidentification 

of Hanleyella oldroydi, which is relatively common in 

SCB samples, and may bear a superficial resemblance to 

Hanleya to non-chiton workers in terms of valve and 

girdle morphology. 

It is unknown which species or even which genus 

the unidentified “Ischnochiton” may represent. Although 

one species of Stenosemus (considered by some a 

subgenus of Ischnochiton), S. stearnsii, could range into 

the shelf and upper slope depths sampled off southern 

California as noted above, this species is so far known 

from only much deeper waters (> 400 m) and has not 

been confirmed by benthic monitoring programs in the 

region. It is more likely that the specimen represented a 

misidentification of Lepidozona radians or L. retiporosa, 

which are each known from the present study. Both 

species have previously been placed within Ischnochiton, 

probably because neither has the pronounced dorsal 

sculpturing apparent in other members of Lepidozona, and 

their assignment to Lepidozona partly depends on valve 

features only visible after valves are disarticulated (e.g., 

“jugal plate separated from apophyses by small notches” 

in Kaas & Van Belle, 1987). Another, somewhat 

doubtful, possibility is that the specimen could have been 

Ischnochiton newcombi Carpenter in Pilsbry, 1892 (type 

locality “California, Sta. Catalina Island”), which is only 

known from the holotype (see Kaas & Van Belle, 1990). 

Finally, it is remarkable that southern California still 

lacks a complete treatment of chitons for shallower depths 

than those covered here. While intertidal chitons are 

relatively well known, very little is known about subtidal 

chitons accessible by SCUBA. Three examples were 

brought to light by the recent examination of collections 

made by the late David Mulliner while diving about one 

mile off the coast of Point Loma, San Diego, each species 

which is also likely to occur in deeper waters of the 

region (see Table 1). The first is a lot of five specimens 

of typical Oldroydia percrassa (Plate 9, Figure 22), which 

were collected at depths of 15-18 m in October 1972. We 

fully expect that this species will eventually be collected 

at depths that were the focus of this study. Likewise, two 

lots of Callistochiton decoratus (Figure 23), representing 

15 specimens also collected from 15-18 m in 1972 and 

1975, reveal that this species is relatively common at 

those depths, and it seems likely it may also occur in 

deeper waters of the region. Finally, a single individual of 

the rare Stenoplax corrugata (Figure 24), which was the 

first specimen either of us had ever seen, was collected at 

18-20 m in February 1973 and originally identified as 

“Stenoplax sp.” After we had studied this specimen, DJE 

collected a second S. corrugata specimen off San Pedro 

using a rock dredge (February 29, 2008; length ~35 

mm; 23-29 m on a rock). Again, it is likely that this 

species occurs at the depths treated herein, but has been 

missed because of its rarity or because it is restricted to a 

specific unsampled rocky bottom habitat. It is our hope 

that we can next undertake a companion contribution on 

the intertidal and shallow subtidal chitons of southern 

California and northern Baja California, but we will need 

the similar cooperation of those dedicated to discovering 

the habitat and ecology of chitons accessible by diving.


Endnote 

As part of this study we also investigated a 

suggestion made by Coan (1985) and adopted in Turgeon 

et al. (1998) to recognize little-known descriptions 

provided by Josiah Keep in 1887 for two species of 

Callistochiton that occur in southern California waters. 

If valid this would a) affect the authority for C. 

decoratus giving priority to Keep (1887) instead of 

Carpenter MS, Pilsbry, 1893, and b) make C. 

crassicostatus Pilsbry, 1893, a junior synonym of C. 

fimbriatus Keep, 1887. The additional description of C. 

palmulatus Carpenter MS in Keep (1887) would not have 

similar priority because this name was validated earlier 

as C. palmulatus Carpenter MS, Dall, 1879, a name for 

which Ferreira (1979a) has designated a neotype. Below 

is a summary of our findings. 

Briefly, Keep (1887) provided short descriptions of 

C. decoratus, C. palmulatus, and C. fimbriatus, in this 

order and all attributed to Carpenter’s manuscript. No 

figures were provided in support of these descriptions 

and, unfortunately, no specimens identified as C. 

decoratus or C. fimbriatus exist in all that apparently 

remains of the Keep Collection, which is now housed at 

Tohoku University (Sendai, Japan). There is one 

Callistochiton included in the collection, a complete set 

of disarticulated valves, identified on the outside of the 

vial as "Callistochiton palmulatus Cpr Monterey" (H. 

Saito and J. Nemoto, personal communication). Further 

complicating matters, our study of the images of these 

valves provided courtesy of J. Nemoto have revealed 

that they correspond instead to C. crassicostatus. 

Based on our review of the available information, 

we feel that Keep’s descriptions of C. decoratus and C. 

fimbriatus are inadequate to distinguish these taxa from 

each other or any other species of Callistochiton. 

Additionally, given the sparse and inadequate 

descriptions of these species in Keep (1887), the lack of 

identified specimens of either C. decoratus or C. 

fimbriatus in the Keep Collection, and the 

misidentification of Keep’s C. palmulatus material, we 

do not believe it is possible to reliably determine which 

species of Callistochiton Keep was referring to in each 

of his descriptions. Thus, we consider Keep’s 

designations of these two species in 1887 to be nomina 

dubia, and herein retain Callistochiton crassicostatus 

Pilsbry, 1893, and Callistochiton decoratus Carpenter 

MS, Pilsbry, 1893, as the oldest available names and 

authorities for these chitons (see Table 1). 

Acknowledgments 

We thank the staff of the City of San Diego’s ocean 

monitoring program for assistance collecting, processing 

and providing information on many of the chitons 

examined herein, including especially Kelvin Barwick 

(now with Orange County Sanitation District), Dan 

Ituarte, Megan Lilly, Rick Rowe, Wendy Storms and 

Ron Velarde. We are especially grateful to Kelvin 

Barwick for photographic assistance with many 

specimens, Rick Rowe for taking the photographs of live 

specimens of Hanleyella oldroydi (Figure 2b) and 

Lepidozona sp. C (cover), Dan Ituarte for advice and 

help preparing or restoring several of the final images, 

and to Dawn Olson for preparing the map in Figure 1. 

We greatly appreciate the assistance of Don Cadien (Los 

Angeles County Sanitation Districts), Tony Phillips (City 

of Los Angeles), and Christina Thomas and George 

Robertson (Orange County Sanitation District) for 

providing specimens and sampling information from 

their respective monitoring programs. We also thank 

Ananda Ranasinghe of SCCWRP for tracking down 

some elusive station information for the 1994, 1998 and 

2003 SCB regional surveys. We thank David and 

Margaret Mulliner for donation of their chiton 

collections to the University of Michigan Museum of 

Zoology (UMMZ), some of which were photographed 

for this paper (Figures 22-24). Dr. Diarmaid ÓFoighil of 

UMMZ arranged a loan of this material for study. We 

also appreciate the assistance of Paul Valentich-Scott and 

Patricia Sadeghian of the Santa Barbara Museum of 

Natural History for providing digital images (e.g., 

Figure 6b) or type specimens of several chitons for 

comparative purposes. We thank Greg Rouse and Harim 

Cha of the Scripps Institution of Oceanography for the 

loan of specimens from SIO’s Benthic Invertebrate 

Collection. We also thank Eugene Coan (Santa Barbara 

Museum of Natural History), Hiroshi Saito (National 

Museum of Nature and Science, Tokyo), Jun Nemoto 

(Museum of Natural History at Tohoku University, 

Sendai), and Gary Rosenberg (Academy of Natural 

Sciences, Philadelphia) for providing information 

regarding nominal species of Callistochiton described 

briefly by Josiah Keep in 1887. We also appreciate the 

assistance of Enrico Schwabe (Zoologische 

Statssammlung München, Germany) in tracking down 

and providing us with a 19 th century reference. We are 

grateful to Anthony Draeger (Kensington, CA) for useful 

comments on an early draft of the manuscript and for


subsequent discussions, as well as for providing the 

digital image used herein of the Lepidozona 

scabricostata holotype (Figure 6a). We also sincerely 

thank Roger Clark (Eagle Mountain, UT) who 

provided much advice, kindly reviewed and confirmed 

many of the identifications, and for useful comments 

and suggestions that greatly improved our final 

manuscript. Finally, we thank The Festivus Editor-in- 

Chief, Carole Hertz, for her help and patience while 

we finished this paper. TDS acknowledges support 

from the City of San Diego, Metropolitan Wastewater 

Department (Environmental Monitoring and Technical 

Services Division). DJE acknowledges a sabbatical 

fellowship supported by the National Evolutionary 

Synthesis Center (NESCent), NSF #EF-0423641. 

Literature Cited 

ALLEN, RICHARD K. 

1976. Common Intertidal Invertebrates of Southern California. 

Revised Edition. Peek Publications, Palo Alto, CA. 316 pp. 

BAXTER, RAE 

1983. Mollusks of Alaska. China Poot Bay Society Publications, 

Homer, AK. 96 pp. 

BERGEN, MARY, STEVEN B. WEISBERG, DONALD CADIEN, 

ANN DALKEY, DAVID MONTAGNE, ROBERT W. SMITH, 

JANET K. STULL & RONALD G. VELARDE 

1998. Southern California Bight 1994 Pilot Project: IV. Benthic 

Infauna. Southern California Coastal Water Research 

Project, Westminster, CA. 

BERGEN, MARY, STEVEN B. WEISBERG, ROBERT W. SMITH, 

DONALD B. CADIEN, ANN DALKEY, DAVID E. MONTAGNE, 

JANET K. STULL, RONALD G. VELARDE & J. ANANDA 

RANASINGHE 

2001. Relationship between depth, sediment, latitude, and the 

structure of benthic infaunal assemblages on the mainland 

shelf of southern California. Marine Biology, 138: 637- 

647. 

BERRY, S. STILLMAN 

1911. A new Californian chiton. Proceedings Academy of 

Natural Sciences of Philadelphia, 63: 487-492. 

1917. Notes on West American chitons I. Proceedings of the 

California Academy of Sciences, (4) 7 (10): 229-248. 

1919a. Preliminary notices of some new West American chitons. 

Lorquinia, 2 (6): 44-47. 

1919b. Notes on West American chitons II. Proceedings of the 

California Academy of Sciences, (4) 9 (1): 1-36. 

1922. Fossil chitons of Western North America. Proceedings of 

the California Academy of Sciences, (4) 11 (18): 399-526. 

1925. New or little known southern Californian Lepidozonas. 

Proceedings of the Malacological Society of London, 16 

(5): 228-231. 

BRUSCA, GARY J. & RICHARD C. BRUSCA 

1978. A Naturalist’s Seashore Guide. Common Marine Life of 

the Northern California Coast and Adjacent Shores. Mad 

River Press, Eureka, CA. 205 pp. 

BRUSCA, GARY J., WILLIAM MAUCK & RICHARD MEYER 

1971. The Stomatopod’s Guide to the Common Seashore Life of 

Northern California. American Stomatopod Society 

Special Publication, 1: 1-50. 

BUCKLAND-NICKS, JOHN 

1995. Ultrastructure of sperm and sperm-egg interaction in 

Aculifera: implications for molluscan phylogeny. 

Mémoirs du Muséum National d’Histoire Naturelle, 

Paris, 166: 129-153. 

2008. Fertilization biology and the evolution of chitons. 

American Malacological Bulletin, 25: 97-111. 

BURGHARDT, GLENN & LAURA BURGHARDT 

1969. A Collector’s Guide to West Coast Chitons. San 

Francisco Aquarium Society Special Publication, 4: 1-45. 

CARPENTER, PHILIP P. 

1864. Supplementary report on the present state of our 

knowledge with regard to the Mollusca of the West Coast 

of North America. Reports of the British Association for 

the Advancement of Science for 1863: 517-686. 

CITY OF LOS ANGELES 

2007. Santa Monica Bay Biennial Assessment Report 2005- 

2006. Department of Public Works, Bureau of 

Sanitation, Environmental Monitoring Division, Los 

Angeles, CA. 

2008. Los Angeles Harbor Biennial Assessment Report 2006- 

2007. Department of Public Works, Bureau of 

Sanitation, Environmental Monitoring Division, Los 

Angeles, CA 

CITY OF SAN DIEGO. 

2008a. Annual Receiving Waters Monitoring Report for the 

Point Loma Ocean Outfall, 2007. City of San Diego 

Ocean Monitoring Program, Metropolitan Wastewater 

Department, Environmental Monitoring and Technical 

Services Division, San Diego, CA. 

2008b. Annual Receiving Waters Monitoring Report for the 

South Bay Ocean Outfall (South Bay Water Reclamation 

Plant), 2007. City of San Diego Ocean Monitoring 

Program, Metropolitan Wastewater Department, 

Environmental Monitoring and Technical Services 

Division, San Diego, CA. 

CLARK, ROGER N. 

1991. Notes on the distribution, taxonomy, and natural history 

of some North Pacific chitons (Mollusca: 

Polyplacophora). The Veliger, 34 (1): 91-96. 

1994. Review of the genus Placiphorella Dall, 1879, ex 

Carpenter MS (Polyplacophora: Mopaliidae) with 

descriptions of two new species. The Veliger, 37 (3): 

290-311. 

1999. The Tonicella lineata (Wood, 1815) species complex 

(Polyplacophora: Tonicellidae), with descriptions of two 

new species. American Malacological Bulletin, 15 (1): 

33-46. 

2004. On the identity of Von Middendorff’s Chiton stichensis 

and Chiton scrobiculatus. The Festivus, 36 (5): 49-52. 

2008. Two new chitons of the genus Tripoplax Berry, 1919 

from the Monterey Sea Canyon. American Malacological 

Bulletin, 25: 77-86. 

COAN, EUGENE 

1985. A bibliography and list of molluscan names of Josiah 

Keep. The Veliger, 28 (2): 211-215. 

DALL, WILLIAM H. 

1879. Report on the limpets and chitons of the Alaskan and 

Arctic regions, with descriptions of genera and 

subspecies believed to be new. Proceedings of the United 

States National Museum, 1 (for 1878) (48): 281-344. 

1919. Descriptions of new species of chitons from the Pacific 

coast of America. Proceedings of the United States 

National Museum, 55 (2283): 499-516.


EERNISSE, DOUGLAS J. 

1984. Lepidochitona Gray, 1821 (Mollusca: Polyplacophora), 

from the Pacific Coast of the United States: Systematics 

and Reproduction. University of California, Santa Cruz. 

Ph.D. Dissertation. March, 1984. 358 pp. 

1986. The genus Lepidochitona Gray, 1821 (Mollusca: 

Polyplacophora) in the Northeastern Pacific Ocean 

(Oregonian and Californian Provinces). 

ZoologischeVerhandelingen (Leiden), 228: 1-53. 

1998. Class Polyplacophora. Pp. 49-73, in: P. V. Scott & J. A. 

Blake (eds.), Taxonomic Atlas of the Benthic Fauna of 

the Santa Maria Basin and Western Santa Barbara 

Channel. Vol. 8: The Mollusca Part 1. Santa Barbara 

Museum of Natural History, Santa Barbara, CA. 250 pp. 

2004a. The phylogenetic affinities of northern Pacific chitons 

[Abstract]. Pp. 35-36, in: F. E. Wells, (ed.), Molluscan 

Megadiversity: Sea, Land and Freshwater. World 

Congress of Malacology, Perth, Western Australia. 11- 

16 July 2004. Western Australian Museum, Perth. 

2004b. Revival of the genus Cyanoplax Pilsbry, 1892 for a 

clade of West Coast chitons [Abstract]. Pp. 33-35, in: J. 

C. Martínez & R. V. Yeomans, (eds.), Program and 

Abstracts of the 37th Annual Meeting of the Western 

Society of Malacologists, Ensenada, Baja California, 

Mexico. 

2006. Advances in chiton research [Abstract]. Program for 

72nd Annual Meeting of the American Malacological 

Society and 39th Annual Meeting of the Western Society 

of Malacologists, July 29 to August 3, 2006, Seattle, 

WA. 

2007. Chiton phylogeography and new species discovery along 

the Baja California Peninsula [Abstract]. Meeting 

Program for the 40 th 

Annual Meeting of the Western 

Society of Malacologists, La Paz, Baja California Sur, 

Mexico, 26-30 July 2007. 

2008a. Unraveling a tangle: Phylogenetic estimate for Chitonina 

Thiele, 1910 based on 16S ribosomal DNA [Abstract]. 

Program for 41st Annual Meeting of the Western Society 

of Malacologists, June 5 to 8, 2008, Menlo Park, CA. 

2008b. Introduction to the symposium “Advances in Chiton 

Research”. American Malacological Bulletin 25: 21-24. 

EERNISSE, DOUGLAS J., ROGER N. CLARK & ANTHONY 

DRAEGER 

2007. Polyplacophora. Pp. 701-713, in: J. T. Carlton (ed.), 

Light and Smith Manual: The Intertidal Invertebrates of 

Central California to Oregon, 4th Edition. University of 

California Press, Berkeley, CA. 

FERREIRA, ANTONIO J. 

1978. The genus Lepidozona (Mollusca: Polyplacophora) in the 

temperate eastern Pacific, Baja California to Alaska, with 

the description of a new species. The Veliger, 21 (1): 19- 

44. 

1979a. The genus Callistochiton Dall, 1879 (Mollusca: 

Polyplacophora) in the eastern Pacific, with the 

description of a new species. The Veliger, 21 (4): 444- 

466. 

1979b. The family Lepidopleuridae (Mollusca: Polyplacophora) 

in the eastern Pacific. The Veliger, 22 (2): 145-165. 

1982. The family Lepidochitonidae Iredale, 1914 (Mollusca: 

Polyplacophora) in the northeastern Pacific. The Veliger, 

25 (2): 93-138. 

1983. The genus Chaetopleura Shuttleworth, 1853 (Mollusca: 

Polyplacophora) in the warm temperate and tropical 

eastern Pacific, southern California to Peru, with the 

description of two new species. The Veliger, 25 (3): 203- 

224. 

GOULD, AUGUSTUS A. 

1852. United States Exploring Expedition during the years 

1838-1842, under the command of Charles Wilkes, 

U.S.N. 12, Mollusca and shells: I-XV, 1-510 (Boston). 

HADERLIE, EUGENE C. & DONALD P. ABBOTT 

1980. Polyplacophora: the Chitons. Pp. 412-428, in: R. H. 

Morris, D. P. Abbott & E. C. Haderlie (eds.), Intertidal 

Invertebrates of California. Stanford University Press, 

Stanford, CA. 690 pp. 

JAKOVLEVA, ANASTASIA M. 

1952. Shell-bearing Mollusks (Loricata) of the Seas of the 

U.S.S.R. In: Keys to the Fauna of the U.S.S.R., 45, 

Zoological Institute of the Academy of Sciences of the 

U.S.S.R., Moskwa and Leningrad, 127 pp. 

KAAS, PIET, ALLAN M. JONES & KAREN L. GOWLETT- 

HOLMES 

1998. Class Polyplacophora. Pp. 161-194, in: P. L. Beesley, 

G. J. B. Ross, and A. Wells (eds.), Mollusca: The 

Southern Synthesis. Fauna of Australia. Vol. 5. Part A. 

xvi+563 pp., CSIRO Publishing, Melbourne. 

KAAS, PIET & RICHARD A. VAN BELLE 

1980. Catalogue of Living Chitons (Mollusca: Polyplacophora). 

Dr. W. Backhuys, Publisher, Rotterdam, 144 pp. 

1985a. Monograph of Living Chitons (Mollusca: 

Polyplacophora). Volume 1. Order Neoloricata: 

Lepidopleurina. E. J. Brill, Leiden. 240 pp. 

1985b. Monograph of Living Chitons (Mollusca: 

Polyplacophora). Volume 2. Suborder Ischnochitonina. 

Ischnochitonidae: Schizoplacinae, Callochitoninae and 

Lepidochitoninae. E. J. Brill, Leiden. 198 pp. 

1987. Monograph of Living Chitons (Mollusca: 

Polyplacophora). Volume 3. Suborder Ischnochitonina. 

Ischnochitonidae: Chaetopleurinae and Ischnochitoninae 

(pars). Additions to Vols. 1 and 2. E. J. Brill, Leiden. 

302 pp. 


Polyplacophora). Volume 4. Suborder Ischnochitonina: 

Ischnochitonidae: Ischnochitoninae (continued); 

Additions to Vols. 1, 2 and 3. E. J. Brill, Leiden. 298 

pp. 


Polyplacophora). Volume 5. Suborder Ischnochitonina: 

Ischnochitonidae: Ischnochitoninae (concluded), 

Callistoplacinae; Mopaliidae; additions to Volumes 1-4. 

E. J. Brill, Leiden. 402 pp. 

1998. Catalogue of Living Chitons (Mollusca: Polyplacophora). 

Second, revised edition. Backhuys Publishers, Leiden, 

204 pp. 

KEEP, JOSIAH 

1887. West Coast Shells. A Familiar Description of the 

Marine, Fresh Water, and Land Mollusks of the United 

States, Found West of the Rocky Mountains. Bancroft 

Bros., San Francisco. 230 pp. 

KELLY, RYAN P. & DOUGLAS J. EERNISSE 

2008. Reconstructing a radiation: the chiton genus Mopalia in 

the north Pacific. Invertebrate Systematics, 22: 17-28. 

KOZLOFF, EUGENE N. 

1983. Seashore Life of the Northern Pacific Coast. An 

Illustrated Guide to Northern California, Oregon, 

Washington, and British Columbia. University of 

Washington Press, Seattle and London. 370 pp.


1996. Marine Invertebrates of the Pacific Northwest. University 

of Washington Press, Seattle and London. 539 pp. 

KUES, BARRY S. 

1974. New occurrences of Ischnochiton retiporosus Carpenter, 

1864, in the Eastern Pacific Ocean. The Veliger, 16 (4): 

366. 

LAMB, ANDY & BERNARD P. HANBY 

2005. Marine Life of the Pacific Northwest. A Photographic 

Encyclopedia of Invertebrates, Seaweeds and Selected 

Fishes. Harbour Publishing, Madeira Park, BC, 398 pp. 

LOS ANGELES COUNTY SANITATION DISTRICTS 

2008. Joint Water Pollution Control Plant Biennial Receiving 

Water Monitoring Report 2006-2007. Whittier, CA. 

MCLEAN, JAMES H. 

1978. Marine Shells of Southern California. Los Angeles 

County Museum of Natural History, Science Series 24, 

Revised Edition. 104 pp. 

MIDDENDORFF, ALEXANDER T. VON 

1847. Vorlaüfige Anzeige bisher unbekannter Mollusken, als 

Vorarbeit zu einer Malacozoologica Rossica. Bulletin de 

la classe physico-mathématique de l’Académie Impériale 

des Sciences Saint Pétersbourg, 6: 113-122. 

MULLINEAUX, LAUREN. S. 

1987. Organisms living on manganese nodules and crusts: 

distribution and abundance at three North Pacific sites. 

Deep-Sea Research, 34: 165-184. 

O’CLAIR, RITA M. & CHARLES E. O’CLAIR 

1998. Southeast Alaska’s Rocky Shores, Animals. Plant Press, 

Auke Bay, AK. 564 pp. 

OKUSU, AKIKO, ENRICO SCHWABE, DOUGLAS J. EERNISSE 

& GONZALO GIRIBET 

2003. Towards a phylogeny of chitons (Mollusca, 

Polyplacophora) based on combined analysis of five 

molecular loci. Organisms Diversity & Evolution, 3: 

281-302. 

OLDROYD, IDA S. 

1927. Chitons. Pp. 246-323, in: The Marine Shells of the West 

Coast of North America. Vol. II, Part III. Stanford 

University Press, Stanford. 

ORANGE COUNTY SANITATION DISTRICT 

2007. Annual Report, July 2005 - June 2006. Marine 

Monitoring. Fountain Valley, CA. 

PILSBRY, HENRY A. 

1892-1893. Monograph of the Polyplacophora (Chitons), 

Lepidopleuridae, Ischnochitonidae, Chitonidae, 

Mopaliidae. In: G. W. Tryon, Manual of Conchology, 

14: 1-128, plts. 1-30 (1892); 129-350, plts 31-68 (1893). 

Academy of Natural Sciences, Philadelphia. 

1918. Descriptions of new species of Mopalia and 

Trachydermon. The Nautilus, 31(4): 125-127. 

PUCHALSKI, STEPHANEY S., DOUGLAS J. EERNISSE & 

CLAUDIA C. JOHNSON 

2008. The effect of sampling bias on the fossil record of 

chitons (Mollusca, Polyplacophora). American 

Malacological Bulletin, 25: 87-96. 

PUTMAN, BARRY F. 

1980. Taxonomic Identification Key to the Described Species 

of Polyplacophoran Mollusks of the West Coast of North 

America (North of Mexico). Report No. 411-79.342, 

Pacific Gas and Electric Company, Department of 

Engineering Research. 165 pp. 

RANASINGHE, J. ANANDA, DAVID E. MONTAGNE, ROBERT 

W. SMITH, TIMOTHY K. MIKEL, STEVEN B. WEISBERG, 

DONALD CADIEN, RONALD VELARDE & ANN DALKEY 

2003. Southern California Bight 1998 Regional Monitoring 

Program: VII. Benthic Macrofauna. Southern California 

Coastal Water Research Project. Westminster, CA. 

RANASINGHE, J. ANANDA, ARTHUR M. BARNETT, KEN 

SCHIFF, DAVID E. MONTAGNE, CHERYL BRANTLEY, CHRIS 

BEEGAN, DONALD B. CADIEN, CURTIS CASH, GREGORY B. 

DEETS, DOUGLAS R. DIENER, TIMOTHY K. MIKEL, ROBERT 

W. SMITH, RONALD G. VELARDE, SUSAN D. WATTS & 

STEVEN B. WEISBERG 

2007. Southern California Bight 2003 Regional Monitoring 

Program: III. Benthic Macrofauna. Southern California 

Coastal Water Research Project. Costa Mesa, CA. 

RICKETTS, EDWARD F., JACK CALVIN & JOEL W. 

HEDGPETH 

1985. Between Pacific Tides. 5th edition. Revised by D. W. 

Phillips. Stanford University Press, Stanford. 652 pp. 

SAITO, HIROSHI 

2000. Polyplacophora. Pp. 9-17, in: T. Okutani, ed., Marine 

Mollusca of Japan. Tokai University Press, Tokyo. 1170 

pp. 

SCAMIT 

1994. A taxonomic listing of soft bottom macroinvertebrates 

from infaunal monitoring programs in the Southern 

California Bight. Edition 1. Southern California 

Association of Marine Invertebrate Taxonomists, San 

Pedro, CA. 72 pp. 

1996. A taxonomic listing of soft bottom macro- and 

megainvertebrates from infaunal and epibenthic 

monitoring programs in the Southern California Bight. 

Edition 2. Southern California Association of Marine 

Invertebrate Taxonomists, San Pedro, CA. 86 pp. 

SCBPP 

1998. Southern California Bight Pilot Project Reports: Volume 

IV. Benthic Infauna: Volume V. Demersal Fishes and 

Megabenthic Invertebrates. Southern California Coastal 

Water Research Project, Westminster, CA. 

SCHWABE, ENRICO 

2005. A catalogue of recent and fossil chitons (Mollusca: 

Polyplacophora) Addenda. Novapex, 6: 89-105. 

2008. A summary of reports of abyssal and hadal 

Monoplacophora and Polyplacophora (Mollusca). 

Zootaxa, 1866: 205-222. 

SIMROTH, HEINRICH 

1894. Dritter Band. Mollusca. I. Abtheilung: Amphineura und 

Scaphopoda. In: Dr. H. G. Bronn’s Klassen und 

Ordnungen des Thier-Reichs wissenschaftlich dargestellt 

in Wort und Bild. Leipzig. C. F. Winter’sche 

Verlagshandlung. 1892-1894. 

SIRENKO, BORIS I. 

1993. Revision of the system of the order Chitonida (Mollusca: 

Polyplacophora) on the basis of correlation between the 

type of gills arrangement and the shape of the chorion 

processes. Ruthenica, 3 (2): 93-117 [in Russian with 

English summary]. 

1997. The importance of the development of articulamentum 

for taxonomy of chitons (Mollusca, Polyplacophora). 

Ruthenica, 7 (1): 1-24. 

2006. New outlook on the system of chitons (Mollusca: 

Polyplacophora). Venus, 65 (1-2): 27-49. 

SIRENKO, BORIS & ROGER CLARK 

2008. Deshayesiella spicata (Berry, 1919) (Mollusca: 

Polyplacophora), a valid species. Ruthenica, 18 (1): 1-7. 

SLIEKER, FRANS J. A. 

2000. Chitons of the World. An Illustrated Synopsis of Recent 

Polyplacophora. L’Informatore Piceno Ed., Ancona, 

Italy. 154 pp.


SMITH, ALLYN G. 

1947a. Class Amphineura, Order Polyplacophora, Families 

Lepidopleuridae, and Lepidochitonidae. Conchological 

Club of Southern California Minutes (J. Q. Burch, ed.), 

66: 3-16. 

1947b. Check list of west North American marine mollusks: 

Class Amphineura, Order Polyplacophora. 

Conchological Club of Southern California Minutes (J. 

Q. Burch, ed.), 66: 17-19. 

1960. Amphineura. Pp. 141-176, in: R. C. Moore (ed.), 

Treatise on Invertebrate Paleontology, Part 1, Mollusca 

1. Geological Society of America, New York. 

SMITH, ALLYN G. 

1975. Class Polyplacophora (Chitons). Pp. 457-466, in: R. I. 

Smith & J. T. Carlton, eds., Light’s Manual: Intertidal 

Invertebrates of the Central California Coast. 3rd 

edition. University of California Press, Berkeley, Los 

Angeles and London. 716 pp. 

SMITH, ALLYN G. & MACKENZIE GORDON, JR. 

1948. The marine mollusks and brachiopods of Monterey Bay, 

California, and vicinity. Proceedings of the California 

Academy of Sciences, (4) 26 (8): 147-245. 

STAROBOGATOV, YAROSLAV I. & BORIS I. SIRENKO 

1975. On the system of Polyplacophora. Pp. 21-23, in: I. M. 

Likharev, ed., Molluscs, their System, Evolution and 

Signification in the Nature. (5 th Meeting on the 

Investigation of Molluscs). USSR Academy of Sciences, 

Zoological Institute, Leningrad. English translation in 

Malacological Review, 11 (1978): 73-74. 

TAKI, ISAO 

1938. Report of the biological survey of Mutsu Bay. 31, 

Studies on chitons of Mutsu Bay with general discussion 

on chitons of Japan. Sci. Rep. Tôhoku imp. Univ. (4) 

Biol. 12 (3): 323-423, figs 1-7, plts. 14-34, maps. 

TURGEON, DONNA D., JAMES F. QUINN, JR., ARTHUR E. 

BOGAN, EUGENE V. COAN, FREDERICK G. HOCHBERG, 

WILLIAM G. LYONS, PAULA. M. MIKKELSEN, RICHARD J. 

NEVES, CLYDE F. E. ROPER, GARY ROSENBERG, BARRY 

ROTH, AMELIE SCHELTEMA, FRED G. THOMPSON, 

MICHAEL VECCHIONE & JAMES D. WILLIAMS 

1998. Common and Scientific Names of Aquatic Invertebrates 

from the United States and Canada: Mollusks. 2nd 

edition. American Fisheries Society, Special Publication 

26, 526 pp. 

VAN BELLE, RICHARD A. 

1983. The systematic classification of the chitons (Mollusca: 

Polyplacophora). Informations de la Société Belge de 

Malacologie, 11: 1-178. 

1985. The systematic classification of the chitons (Mollusca: 

Polyplacophora). Addenda I (with the description of the 

genus Incisiochiton gen. n.). Informations de la Société 

Belge de Malacologie, 13: 49-59. 

1999. Polyplacophora: classification and synonymy of recent 

(sub)genera. The Festivus, 31 (6): 69-72. 

VENDRASCO, MICHAEL J., CHRISTINE Z. FERNANDEZ, 

DOUGLAS J. EERNISSE & BRUCE RUNNEGAR 

2008. Aesthete canal morphology in the Mopaliidae 

(Polyplacophora). American Malacological Bulletin, 25: 51- 

69. 

WATTERS, G. THOMAS 

1990. A review of the recent Eastern Pacific Acanthochitoninae 

(Mollusca: Polyplacophora: Cryptoplacidae) with the 

description of a new genus, Americhiton. The Veliger, 

33 (3): 241-271. 

WU, SHI-KUEI & TAKASHI OKUTANI 

1984. The deepsea chitons (Mollusca: Polyplacophora) 

collected by the R/V Soyo-Maru from Japan. I, 

Lepidopleuridae. Venus, 43 (1): 1-31.


SPECIES PLATES 

(Figures 2-24) 

and 

APPENDIX A


PLATE 1 

(Figures 2-4) 

Figure 2. Hanleyella oldroydi (Bartsch MS, Dall, 1919). (a) Dorsal view of specimen, 4 mm length, collected west 

of Mission Bay, San Diego County, California at a depth of 88 m; (b) Lateral view of live specimen, ~5 mm length, 

collected southwest of Point Loma, San Diego County, California at a depth of 90 m. 

Figure 3. Leptochiton nexus Carpenter, 1864. Dorsal view of 9.3 mm long specimen collected just south of San 

Miguel Island, northern Channel Islands, California at a depth of 71 m. 

Figure 4. Leptochiton rugatus (Carpenter in Pilsbry, 1892). Specimen, 5.4 mm length, collected southwest of La 

Jolla, San Diego County, California at a depth of 117 m: (a) Dorsal view of whole animal; (b) Lateral view of whole 

animal.

Vol. XLI(6): 2009 THE FESTIVUS Page 81


PLATE 2 

(Figures 5-7) 

Figure 5. Callistochiton palmulatus Carpenter MS, Dall, 1879. Dorsal-lateral view of 13 mm long specimen with 

typical bulging, fist-shaped tail valve, collected southwest of La Jolla, San Diego County, California at a depth of 

85 m. 

Figure 6. Type specimens of Lepidozona scabricostata (Carpenter, 1964) and Ischnochiton (Lepidozona) golischi 

Berry, 1919. (a) Dorsal view of holotype of L. scabricostata (USNM 16268; image courtesy of A. Draeger); (b) 

Dorsal view of lectotype of I. (L.) golischi (SBMNH 34395; image courtesy of P. Valentich-Scott and P. Sadeghian); 

(c) Enlarged view of lateral and central areas of I. (L.) golischi lectotype. 

Figure 7. Lepidozona golischi (Berry, 1919). Specimen, 22.5 mm length, collected west of Imperial Beach, San 

Diego County, California at a depth of 98 m: (a) Dorsal view of whole animal; (b) Head valve region; (c) Tail valve 

region; (d) Lateral areas of intermediate valves; (e) Girdle scales.

Vol. XLII(6): 2009 THE FESTIVUS Page 83


PLATE 3 

(Figures 8-9) 

Figure 8. Lepidozona mertensii (von Middendorff, 1847). Specimen, 15 mm length, collected west of Imperial 

Beach, San Diego County, California at a depth of 80 m: (a) Dorsal view of whole animal; (b) Head valve region; 

(c) Tail valve region; (d) Lateral areas of intermediate valves; (e) Girdle scales. 

Figure 9. Lepidozona radians (Carpenter in Pilsbry, 1892). (a) Dorsal view of olive green and brown specimen, 6.9 

mm length, collected west of the Tijuana River, San Diego County, California at a depth of 14 m; (b) Girdle scales 

of previous chiton; (c) Dorsal view of white specimen, 7.4 mm length, collected off Santa Cruz Island, northern 

Channel Islands, California.



PLATE 4 


Figure 10. Lepidozona retiporosa (Carpenter, 1864). Specimen, 17 mm length, collected west of Imperial Beach, 

San Diego County, California at a depth of 98 m: (a) Dorsal view of whole animal; (b) Head valve region; (c) Tail 

valve region; (d) Lateral areas of intermediate valves; (e) Girdle scales. 

Figure 11. Lepidozona scrobiculata (von Middendorff, 1847). Specimen, 15.8 mm length, collected west of the 

Tijuana River, San Diego County, California at a depth of 28 m: (a) Dorsal view of whole animal; (b) Head valve 

region; (c) Tail valve region; (d) Lateral areas of intermediate valves; (e) Girdle scales.



PLATE 5 


Figure 12. Lepidozona sp. A. Specimen, 12.1 mm length, collected southwest of Point Loma, San Diego County, 

California at a depth of 101 m: (a) Dorsal view of whole animal; (b) Head valve region; (c) Tail valve region; (d) 

Lateral areas of intermediate valves; (e) Girdle scales. 

Figure 13. Lepidozona sp. B. Specimen, 13 mm length, collected off Palos Verdes, Los Angeles County, California 

at a depth of 305 m: (a) Dorsal view of whole animal; (b) Head valve region; (c) Tail valve region; (d) Lateral areas 

of intermediate valves; (e) Girdle scales.



PLATE 6 


Figure 14. Lepidozona sp. C. Specimen, 19.5 mm length, collected southwest of Point Loma, San Diego County, 

California at a depth of 90 m: (a) Dorsal view of whole animal; (b) Head valve region; (c) Tail valve region; 

(d) Lateral areas of intermediate valves; (e) Girdle scales. 

Figure 15. Dendrochiton gothicus (Carpenter, 1864). Dorsal view of 5.2 mm long specimen collected in Santa Monica 

Bay, Orange County, California at a depth of 17 m. 

Figure 16. Dendrochiton thamnoporus (Berry, 1911). (a) Dorsal view of 6 mm long specimen collected west of La 

Jolla, San Diego County, California at a depth of 27 m; (b) Dorsal view of 7.3 mm long specimen collected southwest 

of the Tijuana River, San Diego County, California at a depth of 38 m.



PLATE 7 


Figure 17. Mopalia imporcata Carpenter, 1864. (a) Dorsal view of juvenile chiton, 3.5 mm length, collected just south 

of Santa Rosa Island, northern Channel Islands, California at a depth of 46 m; (b, c) Close-ups of girdle bristles of 

juvenile chiton; (d) Anterior end of 15 mm long adult chiton collected in Santa Monica Bay at a depth of ~69 m; 

(e) Close-up of girdle bristle of adult chiton. 

Figure 18. Mopalia lowei Pilsbry, 1918. Juvenile chiton, 5 mm length, collected in Santa Monica Bay, Orange 

County, California at a depth of 17 m; (a) Dorsal view of whole animal; (b) Close-up of girdle bristles. 

Figure 19. Mopalia phorminx Berry, 1919. Specimen, 20 mm length, collected off Palos Verdes, Los Angeles County, 

California at a depth of 100 m: (a) Dorsal view of whole animal: (b) Close-up of girdle bristles.



PLATE 8 


Figure 20. Placiphorella mirabilis Clark, 1994. Specimens collected southwest of La Jolla, San Diego County, 

California at a depth of 104 m: (a) Dorsal view of ~17 mm preserved “green” specimen; (b) Dorsal view of 

~18 mm preserved “red” specimen; (c) Dorsal view of live specimen, ~25 mm length, showing typical girdle 

pigmentation. 

Figure 21. Tonicella venusta Clark, 1999. Curled specimen, ~10 mm length, collected just off the eastern side of 

San Miguel Island, northern Channel Islands, California at a depth of 15 m: (a) Dorsal view of whole animal showing 

valves I-VI; (b) Enlarged view of valves III-VI.



PLATE 9 


Figure 22. Oldroydia percrassa (Dall, 1894). Specimens collected by D. Mulliner, scuba divng, 1 mile offshore of 

Point Loma, San Diego County, California, depth of 50-60 ft, Oct. 1972, (UMMZ Cat. No. 252687): (a) Dorsal view 

of 22 mm specimen; (b) Dorsal view of 21 mm specimen with girdle spines intact (not broken off). 

Figure 23. Callistochiton decoratus Carpenter MS, Pilsbry, 1893. Dorsal view of specimen, 20 mm length, collected 

by D. Mulliner, scuba diving, 1 mile offshore of Point Loma, San Diego County, California, depth of 50-60 ft, Oct. 

1972, (UMMZ Cat No. 252668). 

Figure 24. Stenoplax corrugata (Carpenter in Pilsbry, 1892). Dorsal view of specimen, 24.5 mm length, collected 

by D. Mulliner, scuba diving, 1 mile offshore of Point Loma, San Diego County, California, depth of 60-65 ft, Feb. 

1973, (UMMZ Cat. No. 252650).



Appendix A. List of stations from North to South where chitons have been collected in the Southern California Bight 

(SCB) by regular or regional benthic monitoring programs (see Figure 1). Species collected at each site from single 

or multiple samples are indicated (N = number of chiton samples/station). Monitoring programs principally 

responsible for sampling each station are City of San Diego (CSD), Orange County Sanitation District (OCSD), City 

of Los Angeles (CLA), Los Angeles County Sanitation Districts (LACSD), 1994 SCB Pilot Project (SCBPP), and 

1998, 2003 and 2008 SCB Regional Monitoring Programs (Bight’98, Bight’03, Bight’08). Main regions within the 

SCB where chitons were collected include northern Baja California (BC), San Diego (SD), Orange County (OC), Palos 

Verdes (PV), Santa Monica Bay (SMB), Point Conception (PC), and the northern Channel Islands (CI), the latter 

including sites off San Miguel Island (SMI), Santa Rosa Island (SRI), Santa Cruz Island (SCI), and Anacapa Island 

(AI). * = coordinates unknown (stations not shown in Figure 1). 

Station 

N 

Depth 

(m) 

Latitude 

(N) 

Longitude 

(W) 

Monitoring 

Program Region Species Present 

103 1 93 34.421 120.184 SCBPP PC H. oldroydi 

PC-1 1 150 * * LACSD PC L. rugatus, L. radians 

2480 1 106 34.150 120.355 Bight98 CI(SMI) L. rugatus 

2477 1 15 34.058 120.405 Bight98 CI(SMI) D. thamnoporus, T. venusta 



4159 1 71 33.995 120.337 Bight03 CI(SMI) L. nexus, L. rugatus 

4417 1 46 33.890 120.082 Bight03 CI(SRI) M. imporcata 

2538 1 120 34.101 119.729 Bight98 CI(SCI) L. radians 

2518 1 112 34.097 119.737 Bight98 CI(SCI) L. rugatus, L. retiporosa 

2493 1 44 34.079 119.888 Bight98 CI(SCI) L. scrobiculata 

2479 1 84 34.069 119.770 Bight98 CI(SCI) L. rugatus 

4029 1 75 34.034 119.352 Bight03 CI(AI) H. oldroydi, L. nexus, 

L. rugatus, L. retiporosa, 

Lepidozona sp. 

E1 1 150 33.988 118.714 CLA SMB L. rugatus 

A1 6 15-18 33.986 118.502 CLA SMB L. nexus, L. scrobiculata, 

D. gothicus, 

D. thamnoporus, M. lowei 

NB1 1 70 33.913 118.555 CLA SMB L. nexus, L. rugatus 

Z2 2 60 33.912 118.521 CLA SMB L. retiporosa, 

L. scrobiculata 

D1 1 74 33.912 118.550 CLA SMB L. retiporosa


Station 

N 

Depth 

(m) 

Latitude 

(N) 

Longitude 

(W) 

Monitoring 


FA13 1 82 33.907 118.568 CLA SMB L. nexus 

Short Bank 2 56 33.893 118.538 CLA SMB H. oldroydi, L. mertensii, 

L. retiporosa 

FA10 1 54 33.885 118.508 CLA SMB L. rugatus 

7415 1 69 33.856 118.516 Bight08 SMB M. imporcata 

T0-60 1 ~60 33.814 118.431 LACSD PV L. retiporosa 

T1-1000 1 305 33.726 118.427 LACSD PV L. rugatus, L. retiporosa, 

Lepidozona sp. B 

V50 1 50 33.667 118.269 LACSD PV H. oldroydi 

V80/V50 1 48-90 33.667 118.273 LACSD PV L. scrobiculata 

E40 1 40 33.666 118.268 LACSD PV L. rugatus 

E60 1 60 33.655 118.274 LACSD PV L. nexus 

E-80 1 82 33.652 118.276 LACSD PV L. retiporosa 

TA-100 1 100 * * LACSD PV M. phorminx 

TA-130 1 130 * * LACSD PV L. retiporosa, M. phorminx 

T3 1 55 33.581 117.956 OCS OC L. retiporosa 

2015 1 109 32.868 117.332 CSD SD L. rugatus 


B5 1 62 32.821 117.327 CSD SD H, oldroydi, L. retiporosa 

2655 1 27 32.818 117.301 CSD SD D. thamnoporus, 


1767 1 85 32.805 117.347 SCBPP SD C. palmulatus, L. mertensii 


1774 1 104 32.793 117.370 SCBPP SD P. mirabilis 

B11 8 88 32.776 117.356 CSD SD H. oldroydi, L. rugatus, 

L.retiporosa 

2023 3 89-91 32.775 117.358 CSD SD H. oldroydi, L. rugatus, 

L. radians 

B13 4 116 32.773 117.377 CSD SD H. oldroydi, L. rugatus, 

Leptochiton sp. 

SD14 1 100 32.738 117.349 CSD SD L. retiporosa


Station 

N 

Depth 

(m) 

Latitude 

(N) 

Longitude 

(W) 

Monitoring 



SD13 1 101 32.714 117.338 CSD SD L. golischi, L. scrobiculata 

A16 1 61 32.676 117.284 CSD SD H. oldroydi 

SD9 3 88-92 32.654 117.314 CSD SD L. retiporosa, 


2125 1 157 32.645 117.433 CSD SD L. rugatus, L. retiorosa 

2035 1 149 32.639 117.431 CSD SD L. retiporosa 

7029 1 150 32.636 117.417 Bight08 SD L. rugatus 

2189 1 191 32.635 117.357 CSD SD H. oldroydi 

2190 1 99 32.628 117.328 CSD SD H. oldroydi 

SD8 3 90-99 32.626 117.323 CSD SD H. oldroydi, L. retiporosa, 

Lepidozona sp. C 

4388 1 141 32.593 117.391 Bight03 SD H. oldroydi, L. retiporosa 

SD7 1 98-101 32.584 117.307 CSD SD L. golischi, L. retiporosa, 

L. scrobiculata, 

Lepidozona sp. A 

2336 1 9 32.577 117.143 Bight98 SD L. radians 

2095 1 80 32.577 117.281 CSD SD C. palmulatus, L. mertensi 

SD19 1 28 32.558 117.185 CSD SD L. scrobiculata 

2334 1 14 32.552 117.143 Bight98 SD L. rugatus, L. radians, 


2001 1 43 32.546 117.232 SCBPP SD L. scrobiculata, P. mirabilis 

2335 1 18 32.545 117.155 Bight98 SD L. scrobiculata 

SD18 1 30 32.543 117.189 CSD SD L. scrobiculata 

I16 1 23 32.538 117.183 CSD SD L. scrobiculata 

I13 1 38 32.538 117.212 CSD SD D. thamnoporus, 

M. imporcata 

SM152 1 31 32.485 117.179 CSD BC L. radians 

SD15 1 29 32.473 117.175 CSD BC L. scrobiculata, 

D. thamnoporus

ERRATA * 

Stebbins, T. D., and D. J. Eernisse. 2009. Chitons (Mollusca: Polyplacophora) known from benthic monitoring 

programs in the Southern California Bight. The Festivus, (Special Issue) 41(6): 53-100 

1. Cover photo caption (facing page 53): The chiton depicted in the cover photo is Lepidozona sp. C (not 

Lepidozona sp. A). The correct legend should be: 

Live specimen of Lepidozona sp. C occurring on a piece of metal debris collected off San Diego, southern 

California at a depth of 90 m. Photo provided courtesy of R. Rowe. 

2. Page 56: The symbol † next to "Sources" at the top right of Table 1on this page should be changed to a ‡ to 

match the footnote at the bottom of the page (i.e., Sources ‡ ). 

3. Page 58: In the footnote at the bottom of the page, Leptochiton cf. belknapi should be spelled with a period 

after the "cf" instead of a comma. 

4. Page 80: In the caption for Figure 2, the sample depth listed for the chiton depicted in Figure 2a should be 

88 m instead of 18 m. The correct legend should be: 

Figure 2. Hanleyella oldroydi (Bartsch MS, Dall, 1919). (a) Dorsal view of specimen, 4 mm length, 

collected west of Mission Bay, San Diego County, California at a depth of 88 m; (b) Lateral view of live 

specimen, ~5 mm length, collected southwest of Point Loma, San Diego County, California at a depth of 

90 m. 

______________________________________________________________________________________ 

The above errata to the original hardcopy version of this paper that was published on June 11, 2009 will be 

published in a forthcoming issue of The Festivus. However, these errors have already been corrected in 

this PDF version of the paper. [TDS, June 2009]

Chitons (Mollusca: Polyplacophora) - Biological Science - California ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?