A revision of the Zenometridae (new rank) (Echinodermata, Crinoidea, Comatulidina)

Charles G. Messing; Christopher M. White

ABSTRACT.—Hispaniolan cichlids are poorly known, and because of the questionable taxonomic status of two species, the group is reviewed. Nandopsis vombergi (Ladiges, 1938) is regarded here as a junior subjective synonym of the widespread Hispaniolan species Nandopsis haitiensis (Tee-Van, 1935). The holotype and only known specimen of N. vombergi lacks any features that discriminate it from N. haitiensis.

A revision of the Zenometridae (new rank) (Echinodermata, Crinoidea, Comatulidina) Blackwell Science, Ltd CHARLES G. MESSING & CHRISTOPHER M. WHITE Accepted: 15 January 2001 Messing, C. G. & White, C. M. (2001). A revision of the Zenometridae (new rank) ( Echinodermata, Crinoidea, Comatulidina). — Zoologica Scripta, 30, 159 – 180. Three genera of unstalked crinoids, Zenometra, Sarametra and Psathyrometra, formerly included in the subfamily Zenometrinae of the family Antedonidae, are removed and placed in a distinct family, the Zenometridae. Diagnostic features include a cavernous centrodorsal cavity, a complete basal circlet with a large central lumen and cirrus sockets with a concave fulcral bowl around the lumen. Sarametra nicobarica is synonymized under S. triserialis, which is redescribed in detail. Psathyrometra is redefined and includes only the species P. fragilis, P. congesta and P. bigradata, which are redescribed. P. erythrizon is synonymized under P. fragilis. The four other species formerly included in Psathyrometra are removed to Athrypsometra gen. n., retained in the Antedonidae. The other genera formerly included in the Zenometrinae are considered incertae sedis in the family Antedonidae pending detailed re-examination. Cladistic analysis using the antedonids, Poliometra prolixa (a former zenometrine) and Florometra serratissima, and the thalassometrid, Oceanometra annandalei, as outgroups produces the following tree: (O. annandalei((F. serratissima/P. prolixa)(((P. fragilis/P. congesta)P. bigradata) (S. triserialis/Z. columnaris)))). Charles G. Messing and Christopher M. White, Nova Southeastern University Oceanographic Center, 8000 North Ocean Drive, Dania Beach, FL 33004, USA. E-mail: messingc@nova.edu Introduction The family Antedonidae includes over 150 nominal species, about a quarter of all known comatulid crinoids. A. H. Clark (1909a) distinguished six subfamilies — Antedoninae, Bathymetrinae, Heliometrinae, Isometrinae, Perometrinae and Zenometrinae — on the basis of the arrangement and structure of cirri and the structure and composition of oral pinnules (modified by Clark & Clark 1967). These subfamilial distinctions are not entirely satisfactory, however. For example, A. M. Clark (in Clark & Clark 1967) noted that cirrus sockets in columns (i.e. vertical rows), supposedly diagnostic of zenometrines, also appeared in some heliometrines, and that it was difficult to decide whether some species belonged to the Zenometrinae or Bathymetrinae. In fact, the appearance of all intermediate stages of socket arrangements, between well-marked columns on a columnar centrodorsal and completely irregular on a low hemispheric centrodorsal, led A. M. Clark (1980: 199, footnote) to ‘consider that these two subfamilies [Zenometrinae and Bathymetrinae] should be merged’. However, scanning electron microscopic examination of disassociated skeletal ossicles reveals several important characteristics that distinguish species in three zenometrine genera from all other antedonids, recommending their placement in a separate family. New material of several © The Norwegian Academy of Science and Letters • Zoologica Scripta, 30, 3, July 2001, pp159 – 180 species also permits a clearer understanding of specific and generic boundaries. The text includes the following abbreviations for museum catalogue numbers: USNM — National Museum of Natural History, Smithsonian Institution (US National Museum); BMNH — British Museum of Natural History, London; MNHN — Muséum National d’Histoire Naturelle, Paris (EcCh: in alcohol; EcCs: dry); UMML — Invertebrate Museum, Rosenstiel School of Marine and Atmospheric Science, University of Miami; MCZ — Museum of Comparative Zoology, Harvard University. Terminology follows that of Messing (1995, 1997, 1998). Systematic part Family ZENOMETRIDAE Zenometrinae A. H. Clark 1909a: 176. — A. H. Clark & A. M. Clark 1967: 42, 491– 495 (part). Type genus. Zenometra A. H. Clark (1907a) Other included genera. Psathyrometra A. H. Clark, 1907a (part, emended herein); Sarametra A. H. Clark, 1917. 159 A revision of the Zenometridae • C. G. Messing & C. M. White Fig. 1 A–D. Psathyrometra fragilis (USNM E51600). —A. Centrodorsal, oblique lateral view with one attached basal ossicle (B). —B. Cirrus sockets. —C. Zenometra columnaris, cirrus sockets. —D. Sarametra triserialis, cirrus sockets. Scale bars: a, 1.0 mm; b–d, 0.25 mm. 160 Zoologica Scripta, 30, 3, July 2001, pp159 – 180 • © The Norwegian Academy of Science and Letters C. G. Messing & C. M. White • A revision of the Zenometridae Diagnosis A family of comatulid crinoids in which the centrodorsal is completely hollow with little if any overhanging oral rim and without interior radial or interradial pockets or pits (Fig. 1a). Cirrus sockets with a concave fulcral bowl surrounding the central lumen (Fig. 1b–d); the proximal facet of the first cirral with a corresponding large boss. Basals forming a thin, complete circlet with a large central lumen (Fig. 2a– c); each visible externally as a pentagonal extension of one of the interradial ridges (or flat strips) of the centrodorsal, often extending laterally as an extremely narrow strip in deep subradial clefts; adjacent basals may or may not meet midradially in external view. Additional characters shared with some other comatulids. Centrodorsal conical to cylindrical, wider across the base than tall to much taller than wide (Fig. 1a). Cirrus sockets in distinct columns segregated into radial areas by interradial ridges or flat strips; one or more obsolete (i.e. lumen closed, no cirrus) apical sockets per radial area usually present; most sockets with a crenulate margin (Fig. 1a–d). Ray ossicles strongly arched aborally with muscular fossae accounting for at least half the height of the articular faces. At least first segment of proximal pinnules longer than wide; distal pinnulars extremely slender. Remarks Clark & Clark (1967: 492) diagnosed the antedonid subfamily Zenometrinae as follows: ‘… cirri, which are long with numerous, rarely less than 20, segments, are arranged in definite columns, rarely obscured, which are sometimes separated into radial groups by interradial spaces; the centrodorsal is conical, sometimes columnar [= cylindrical] and may be higher than wide, rarely it is low rounded conical; the cirri are usually weakly attached to the centrodorsal; P1 usually resembles P2 and has mostly elongated segments; rarely some of the lower pinnules may be absent.’ Fig. 2 A. Zenometra columnaris, base of centrodorsal showing two basals (B) and one radial (R); centrodorsal margin broken in rear. — B. Sarametra triserialis, basal circlet surrounding centrodorsal central cavity. — C. Psathyrometra fragilis (USNM E51600), two basals. —D. Atelecrinus balanoides, basal ossicle. Scale bars: A–C, 0.5 mm; D, 0.25 mm. © The Norwegian Academy of Science and Letters • Zoologica Scripta, 30, 3, July 2001, pp159 – 180 161 A revision of the Zenometridae • C. G. Messing & C. M. White None of these features is clearly autapomorphic. All extant comatulids have cirrus sockets arranged in a basic double spiral pattern. The growing centrodorsal adds additional cirri at the margin so that adjacent sockets are offset along the aboral/oral axis, not side-by-side (Messing 1997). Similar bispiral arrangements are widespread among plants (e.g. seeds on strawberries and pinecones, florets on Asteraceae). A regular bispiral arrangement may place sockets from adjacent spiral rows along the same aboral/oral line, superimposing columns on the spirals. However, as noted above, distinguishing sockets in columns from those described as ‘in rows’ or ‘arranged irregularly’ is often problematic. Indeed, descriptions of several former zenometrine taxa refer to irregular columns (e.g. Leptometra celtica, Eumorphometra concinna) or columns distinguishable only interradially (e.g. E. hirsuta, E. fraseri, Hybometra senta) (Clark & Clark 1967). Segregation of sockets in radial areas delimited by interradial ridges or flat strips reinforces the appearance of columns (Fig. 1a). Although characteristic of the three zenometrid genera, this feature also appears in thalassometrids, charitometrids, atelecrinids and several other former zenometrines (Balanometra, Anisometra, Adelometra). With respect to the other former diagnostic features, heliometrines and thalassometrids also have long cirri composed of numerous segments, and thysanometrines, such as Coccometra hagenii, have easily deciduous cirri. The short proximal oral pinnule segments of several former zenometrines (e.g. H. senta, L. celtica, E. hirsuta, Poliometra prolixa) have more in common with a variety of non-zenometrine antedonids (e.g. Hypalometra defecta, Perometra robusta) than they do with Zenometra, Sarametra and Psathyrometra. The new familial diagnosis segregates a group of closely similar taxa distinguishable from other antedonids. The distinctive concave fulcral stereom surrounding the cirrus socket lumen (Fig. 1a–d) and completely hollow centrodorsal (Figs 1a, 2b) are autapomorphic. All three genera have thin basals that form a complete circlet with a large central lumen (Fig. 2a– c). In the two dissociated specimens of Psathyrometra fragilis, the medial ends of the basals (= their inner ends, i.e. nearest the oral/aboral axis) bear two openings each: continuations of the aboral nerve canals of the overlying radial ossicles (Fig. 2c). The stereom surrounding these openings corresponds to the interradial and radial processes of the antedonid rosette. However, a rosette as a discrete, centrally perforated, decagonal plate does not exist. The arrangement is similar to but much broader than the ‘compound basals’ of comasterids that consist of a basal ray plus an interradial portion of the rosette (A. H. Clark 1915; Breimer 1978). In the only dissociated specimen of Sarametra triserialis, the basal ossicles are the same shape as in P. fragilis, but the central, perforated stereom is missing (Fig. 2b). The specimen was, according to its label, initially preserved in Bouin’s 162 fixative, which may have partly decalcified the stereom and eliminated more delicate structures. These broad basals differ substantially from those that form a complete circlet in the Atelecrinidae (Fig. 2d). In the two Zenometra columnaris examined, the basals are similar to those of the dissociated S. triserialis, but much narrower; a central rosette is again absent (Fig. 2a). We have examined representatives of seven of the 11 former zenometrine genera not transferred to the Zenometridae: Poliometra prolixa (Sladen) (BMNH 1970.6.3.47.49), Eumorphometra aurora John ( holotype, BMNH 1938.12.7.109), Cyclometra flavescens A. H. Clark ( holotype, BMNH 1910.1.26.1), Anisometra frigida John (holotype, BMNH 1948.1.7.207), Adelometra angustiradia (Carpenter) (holotype, BMNH 88.11.9.86), Balanometra balanoides (Carpenter) (holotype, BMNH 88.11.9.64), Caryometra atlantidis A. H. Clark ( holotype, MCZ 1011; paratypes MCZ 1060; also MCZ 1062–1067), Caryometra spinosa A. H. Clark (holotype, MCZ 1014; also MCZ 1068, 1069) and Psathyrometra acuta A. H. Clark [USNM E3904, a synonym of Caryometra tenuipes (A. H. Clark) ]. All have shallow cirrus sockets with raised rather than concave fulcral stereom. The characteristic zenometrid sockets described above are never present. Published descriptions of the four remaining genera (Kempometra John, Eometra A. H. Clark, Hybometra A. H. Clark and Leptometra A. H. Clark) give no indication of characteristics in common with the three genera removed to the new family. All have closely crowded sockets on centrodorsals that are never taller than wide. In Leptometra celtica, the opening of the centrodorsal cavity (A. H. Clark 1915: 262, fig. 287) is only 0.35 of the centrodorsal diameter, similar to that of other antedonids, but much smaller than in the three zenometrids. Caryometra tenuipes and C. atlantidis are the only former zenometrines (besides the three transferred genera) with basals visible externally, in both cases as small rhombic interradial features (Clark & Clark 1967). C. tenuipes has a tall conical centrodorsal similar to that of some S. triserialis and Psathyrometra, but its cirrus sockets are not segregated into radial areas by interradial spaces or ridges, and the first several segments of P1 are short. A disassociated specimen of C. atlantidis lacks a rosette; its basals are rod-like and forked interiorly, and its centrodorsal cavity, although lacking an overhanging rim, accounts for only 0.42 of the centrodorsal base. In both species, a raised fulcral mound surrounds the cirrus socket lumen. It remains unclear to which subfamilies these 11 former zenometrine genera should be transferred. Variations in socket arrangement and structure and proportions of oral pinnule segments indicate that they do not form a coherent group. As examples, the holotype of Anisometra frigida has poorly defined sockets almost flush with the centrodorsal surface. In the holotype of Adelometra angustiradia, a pair of narrow Zoologica Scripta, 30, 3, July 2001, pp159 – 180 • © The Norwegian Academy of Science and Letters C. G. Messing & C. M. White • A revision of the Zenometridae triangular fulcral ridges flanks the socket lumen. Leptometra and Kempometra have compressed cirrus sockets. Although Cyclometra flavescens was originally placed in the Heliometrinae on the basis of its oral pinnules composed of numerous short segments, A. M. Clark (in Clark & Clark 1967: 493) noted that it was difficult to choose whether to place it in the Zenometrinae or Bathymetrinae. As a result, all (Adelometra, Anisometra, Balanometra, Caryometra, Cyclometra, Eometra, Eumorphometra, Hybometra, Kempometra, Leptometra and Poliometra) are considered incertae sedis at the subfamilial level herein. Genus Zenometra A. H. Clark, 1907a Zenometra A. H. Clark 1907a: 354; Clark & Clark 1967: 495– 496. Type species. Antedon columnaris Carpenter, 1881. Diagnosis A genus of Zenometridae having a cylindrical centrodorsal with well-developed interradial ridges (truncated conical with weak ridges in small specimens). Aboral pole flat or irregularly eroded and excavated. Basals narrow interradially; rosette absent. First segment of P1 with length/width (L/W ) at least 2.0. Additional characters. Centrodorsal taller than wide at the base. Cirrus sockets in two columns per radial area. Distal cirrals shorter than long; all but the basal few cirrals with an aboral distal spine. Socket margins finely crenulate; concave fulcral stereom restricted to central bowl surrounding socket lumen. Proximal ray ossicles bordered by long slender spines webbed with tissue. Zenometra columnaris (Carpenter, 1881) (Figs 1c, 2a, 3) Antedon columnaris Carpenter 1881: 152, 169, pl. 1, fig. 8. Zenometra columnaris A. H. Clark 1907a: 354; 1915: 37, 44, 220, 241 (figs 215, 216), 243 (fig. 217), 301 (fig. 378); 1921: 61, 62 (figs 93, 94), 76, 101, 271, 285, 292, 349 (fig. 754), 378 (fig. 800); Clark & Clark 1967: 496–499; Messing & Dearborn 1990: 16, 26, fig. 12. Zenometra pyramidalis A. H. Clark 1908: 221, 237. Material examined. BLAKE PLATEAU: USNM 34630 (neotype) ‘Albatross’ sta. 2663, 29°39′ N, 79°49′ W, 769 m, 4 May 1886; USNM 22668 (1), USNM 34569 (3, dissociated), USNM 34571 (1), USNM 36141 (1), USNM 36249 (1, centrodorsal and radials only), ‘Albatross’ sta. 2415, 30°44′ N, 79°26′ W, 804 m, 1 April 1885; USNM 36214 (1, dry), ‘Albatross’ sta. 2416, 31°26′ N, 79°07′ W, 504 m, 1 April 1885; USNM E17962 (8), ‘Gerda’ sta. 181, 27°57′ N, 78°56′ W, 779 m, 2 July 1963. STRAITS OF FLORIDA: USNM E17905 (arm fragments), ‘Gerda’ sta. 808, 26°38′ N, 79°33′ W, 751 m, 13 September 1966. SW OF HAITI: USNM E17831 (2), ‘Pillsbury’ sta. 1187, 18°17′ N, 75°07′ W, 1034 m, 2 July 1970. LESSER ANTILLES: (1, lost) ‘Blake’ sta. 222, 13°58′37″ N, 61°04′45″ W, 771 m, 16 February 1879. WEST OF GIBRALTAR: BMNH 1976.7.30.34 (1), ‘Shackleton’ sta. 169 (cruise 3), 3465– 4015 m, 36°17.2′–36°17.9′ N, 12°34.6– 12°35.3′ W, 21 April 1973, J. D. George, coll. Fig. 3 A– C. Zenometra columnaris. —A. Cen- trodorsal (radial view) and bases of three rays (spines omitted). —B. Centrodorsal (radial view, with base of rudimentary cirrus) and bases of three rays. —C. Centrodorsal (interradial view, with bases of two cirri) and bases of four rays. Scale bar: 5.0 mm (from Messing & Dearborn 1990). © The Norwegian Academy of Science and Letters • Zoologica Scripta, 30, 3, July 2001, pp159 – 180 163 A revision of the Zenometridae • C. G. Messing & C. M. White Distribution Geographic distribution. Blake Plateau, northern Straits of Florida and Caribbean Sea (Messing & Dearborn 1990). A single specimen collected west of Gibraltar (BMNH 1976.7.30.34) extends the range to the eastern Atlantic. One other record (USNM 34570, ‘Albatross’ sta. 2400), originally catalogued as fragmentary but currently unidentifiable, exists from the Gulf of Mexico (Fig. 14). with the Mediterranean Outflow in the northeastern Atlantic generates warmer temperatures than found at similar depths in the tropical western Atlantic (although the isotherms shown are strongly smoothed). For example, at 1200 m, they note 5 °C near Florida and 10 °C off Gibraltar. However, the trans-basin temperature difference apparently disappears below about 2000 m, and so it is not certain that this accounts for the range variation seen in Z. columnaris. Bathymetric distribution. Western Atlantic: 504–1034 m, chiefly 750–800 m; the Gulf of Mexico fragment was taken at 308 m (Messing & Dearborn 1990). Eastern Atlantic: 3465– 4015 m. Genus Sarametra A. H. Clark, 1917 Remarks The single species, Z. columnaris, was described in detail by Clark & Clark (1967) and briefly redescribed and illustrated by Messing & Dearborn (1990). Apart from the features of the basal circlet and cirrus sockets noted above, the distinctive appearance of this species makes redescription unnecessary. Z. columnaris joins two other amphi-Atlantic comatulids for which eastern Atlantic records are generally deeper. Messing (1978) records Pentametrocrinus atlanticus (Perrier) from about 400– 800 m in the tropical western and 650 –2115 m in the eastern North Atlantic. Trichometra cubensis (Pourtalès) occurs chiefly between 300 and 900 m in the tropical western (with three of 43 records between 900 and 1200 m) (Clark & Clark 1967; Meyer et al. 1978) and from 1300 to about 2400 m in the eastern North Atlantic (A. M. Clark 1980). According to Levitus & Boyer (1994), the warm tongue associated Type species. Zenometra triserialis A. H. Clark, 1908. Sarametra A. H. Clark 1917: 127, 129; Clark & Clark 1967: 506–507. Diagnosis A genus of Zenometridae with a rounded to acutely conical aboral pole on a conical centrodorsal. Base of centrodorsal with short, weak interradial ridges. Obsolete apical sockets with low horseshoe-shaped rim open aborally. Basals broad and tongue-like interradially; rosette absent. First segment of P1 with L/W = 1.1–1.7. Additional characters. Centrodorsal always taller than wide at the base. Cirrus sockets in two to four columns per radial area (generally increasing with growth). Distal cirrals shorter than wide, carinate or with an aboral distal spine. Socket margins finely crenulate; concave fulcral stereom restricted to central bowl surrounding socket lumen. Proximal ray ossicles bordered by long, slender, webbed spines. Fig. 4 A–D. Sarametra triserialis (all cen- trodorsals in radial view). —A. USNM 22683 (holotype of S. triserialis), centrodorsal, basals and bases of several cirri. —B. MNHN EcCs 5230, centrodorsal and basals (sutures indistinct). —C. MNHN EcCs 5231, centrodorsal, basals and base of one ray. — D. MNHN EcCh 183, centrodorsal and basals. Scale bar: 1 mm. 164 Zoologica Scripta, 30, 3, July 2001, pp159 – 180 • © The Norwegian Academy of Science and Letters C. G. Messing & C. M. White • A revision of the Zenometridae Sarametra triserialis (all centrodorsals in radial view). — A. MNHN EcCh 181, centrodorsal with bases of several cirri, and bases of three rays. —B. BMNH 1927.5.25.35 (holotype of S. nicobarica), centrodorsal with bases of two cirri. Scale bar: 1 mm. Fig. 5 A,B. Sarametra triserialis (A. H. Clark, 1908) (Figs 1d, 2b, 4 –7) Zenometra triserialis A. H. Clark 1908: 213, 219; 1915: 175 (fig. 109), 241 (fig. 214), 301 (fig. 377). Sarametra triserialis A. H. Clark 1917: 129; 1921: 271, 280, 285, 292, 378 (fig. 801), 724, 729; 1929: 661; Clark & Clark 1967: 507– 508. Sarametra nicobarica A. H. Clark 1929: 635, 661–662; Clark & Clark 1967: 508 – 510. Material examined. HAWAII: USNM 22683 [holotype of Z. triserialis (incorrectly listed as USNM 22682 in Clark & Clark 1967: 508) ], ‘Albatross’, sta. 4122, 21°15′ N, 158°08′ W, 351– 644 m, 26 July 1902. NICOBAR IS: BMNH 1927.5.25.35 (holotype of S. nicobarica), Cable ship ‘Patrol’, on the Madras-Penang cable. WALLIS ET FUTUNA IS: MNHN EcCs 5233 (1 specimen), MUSORSTOM Exped. 7, sta. CP550, 790 m, 1992. NEW CALEDONIA: MNHN EcCh 180 (1), BIOCAL Exped., ‘Jean-Charcot’ sta. CP62, 24°19′ S, 167°48′ E, 1395–1410 m, Bouchet, Metivier & Richer, colls., 2 September 1985; MNHN EcCh 181 (1), MUSORSTOM Exped. 4, ‘Vauban’ sta. CP236, 22°11′ S, 167°15′ E, 495– 550 m, B. Richer-ORSTOM, coll., 2 October 1985. KEI IS./ TANIMBAR, INDONESIA: MNHN EcCh 182 (1) and © The Norwegian Academy of Science and Letters • Zoologica Scripta, 30, 3, July 2001, pp159 – 180 MNHN EcCs 5231 (1), KARUBAR Exped., ‘Baruna Jaya’ sta. CP20, 769–809 m, 05°15′ S, 132°52′ E, Bouchet, Kastoro & Metivier, colls., 25 October 1991; MNHN EcCs 5230 (1), KARUBAR Exped., ‘Baruna Jaya’ sta. CP19, 05°15′ S, 133°01′ E, 605–576 m, Bouchet, Kastoro & Metivier, colls., 25 October 1991; MNHN EcCh 183 (1), KARUBAR Exped., ‘Baruna Jaya’ sta. CP38, 07°40′ S, 132°27′ E, 620–666 m, Bouchet, Kastoro & Metivier, colls., 28 October 1991. COMORO IS: MNHN EcCs 5232 (1), BENTHEDI Exped., ‘Suroit’ sta. F68, 12°29.7′ S, 45°02.3′ E, 400 – 460 m, P. Bouchet, coll., 30 March 1977. Diagnosis Same as for genus. Description Centrodorsal tall conical, sometimes with convex sides; height 2.1–8.9 mm; basal diameter 1.4 – 3.7 mm; H/D (ratio of midradial height to basal diameter) = 1.2– 2.4. Functional cirrus sockets in three columns per radial area in basal half of centrodorsal [four columns peripherally in the holotype of S. nicobarica (Fig. 5b), two throughout in the smallest specimen, MNHN EcCs 5231]; obsolete sockets chiefly in two columns in apical half; each column of 2– 6 functional 165 A revision of the Zenometridae • C. G. Messing & C. M. White Fig. 6 Sarametra triserialis. Outlines of centrodorsals and basals of six specimens showing levels at which three and four columns of sockets per radial area first appear (indicated by diagonal rows of three and four dotted circles, respectively). 1. MNHN EcCs 5231 (solid line); 2. MNHN EcCs 5230 (dotted line); 3. MNHN EcCh 182 (solid line); 4. USNM 22683 (dashed line); 5. MNHN EcCh 183 (solid line); 6. BMNH 1927.5.25.35 (dotted line). and 1–9 obsolete sockets; up to two rudimentary peripheral sockets per radial area. Peripheral 1–3 sockets separated interradially by a weak to moderate ridge or, rarely, a narrow flat strip (absent near apex). Aboral pole rounded to acutely conical, accounting for 14–59% of centrodorsal height, at least partly covered with obsolete sockets, rarely with a few papillae. Many obsolete sockets with distinct horseshoeshaped rim open apically; rims often with lateral spines sometimes arranged in continuous spinose longitudinal ridges almost to apex. Cirri XXXVIII to ~ LXXX (functional sockets) with up to XVIII obsolete sockets per radial area. No large peripheral cirri intact. Clark & Clark (1967) indicate cirri of 60 segments, 40 –45 mm long (one cirrus of the holotype of Z. triserialis reconstructed from four fragments is 40 mm with 53 segments). Longest intact cirrus (holotype) mid-sized, 25 mm long, of 46 cirrals. Largest cirrus fragment (MNHN EcCh 180) is 30 mm long with 55 segments. Cirrals increasing in length from c1 to c7 –9; first two to four cirrals short; following cirral with L/W = 1.0–1.4; c7 sometimes through c12 longest, with L/W = 2.4–3.8; following cirrals gradually shorter, reaching L/W of 1.0 by c21–30 and becoming shorter than wide in distal fourth or fifth of cirrus. Proximal several cirrals cylindrical with distinctly concave aboral margins; following cirrals becoming laterally compressed and wider distally. Weak aboral carina gradually developing on middle cirrals, with sharp distally projecting tip, becoming stronger and gabled (with triangular distal face) with straight or convex aboral margin on short distal cirrals. Opposing spine large, compressed and triangular, rising from entire aboral margin of penultimate cirral. Terminal claw weakly curved, or gently hooked, longer than penultimate cirral. Basals visible as low pentagons bridging and extending laterally into deep subradial clefts. Radials short, with shallow U-shaped distal margin, sometimes swollen at proximolateral Fig. 7 A–C. Sarametra triserialis (all cen- trodorsals in radial view). —A. MNHN EcCh 182, centrodorsal and basals. —B,C. Specimens with two columns of sockets per radial area. — B. MNHN EcCs 5232, centrodorsal and bases of three rays. — C. MNHN EcCs 5233, centrodorsal with bases of several cirri, and basals. Scale bar: 1 mm. 166 Zoologica Scripta, 30, 3, July 2001, pp159 – 180 • © The Norwegian Academy of Science and Letters C. G. Messing & C. M. White • A revision of the Zenometridae corners against basals, and bearing transverse fringe of long spines usually webbed with tissue; W/L = 2.4–5.6 (ratio higher, i.e. ossicle proportionally shorter and wider, in larger specimens). Edge of lateral margins of radial articular facets visible interradially, separating bases of adjacent rays. Sutures between adjacent radials or between radials and centrodorsal sometimes indistinct. Ibr1 with straight or converging lateral margins, concave to V-shaped distal margin (incised by axil), and transverse row of strong webbed spines; W/L = 2.9–5.0. Axil (Ibr2) rhombic, wider than Ibr1 (producing distinct gaps, or ‘water pores’, between adjacent rays), with distal margins concave and proximolateral margins straight or slightly concave; W/ L = 1.0–1.3. Spine row strong along proximal margins, weaker along distal margins. Synarthrial swellings weak to strong. Arms 10, none complete. br1 with proximal margin straight (or almost so), distal margin V-shaped (incised by br2), and exterior margin longer than interior margin; W/L = 2.0–3.6; row of webbed spines curving from distolateral corners across proximal margin. Interior margins of adjacent br1 united proximally and diverging distally, producing water pores distal to axils. br2 roughly triangular (the long exterior margin forming a convex hypotenuse) with proximal angle V-shaped, about 90°, and all margins bordered with strong spines; W/L = 1.0 –1.4; synarthrial swellings weak to strong. br3+4, 0.8– 2.1 mm across, squarish, parallelogram-shaped or weakly cuneate with interior lateral margin longer than exterior, and narrowest across syzygy; W/L = 1.0–1.4; spines present along proximal margin of br3 and both proximal and distal margins of br4. br5–8 oblong or slightly cuneate, with concave lateral margins and sometimes with weak alternating articular tubercles; W/L = 1.0–1.8; spines present along proximal and distal margins; distal margins sometimes slightly everted. br9+10 longer than wide. Two to several brachials following br10 oblong or increasingly cuneate, sometimes with weak alternating articular tubercles; distal margins becoming somewhat everted and bearing strong distally directed spines; W/L = 1.25–1.6. Middle brachials cuneate or triangular, laterally compressed; W/L = 1.3–1.5; distal margins strongly raised, spinose and slightly overlapping succeeding brachial (producing serrate aboral arm profile in lateral view). Distal spines often strongest midaborally or slightly off-centre and alternating on successive brachials. Distal brachials becoming weakly cuneate distally and as long as wide or longer, sometimes with weak distal midaboral spines; W/L = 0.9; brachials almost oblong and much more slender as arm narrows nearer tip; W/L = 0.6. Syzygies at br3+4, br9+10 and br14+15; subsequent interval 2 – 9 (usually 3 – 4). Second syzygy occasionally at br7+8 or br8+9; third sometimes br15+16 or br16+17; a single arm of one specimen lacks a normal br1; its first brachial is a typical br2 followed by a syzygy. © The Norwegian Academy of Science and Letters • Zoologica Scripta, 30, 3, July 2001, pp159 – 180 P1 up to 9.6 mm long, 22 segments; proximal pinnulars compressed (flattened), of about equal length, with some corners truncated; following pinnulars gradually shorter and narrower, becoming extremely slender and delicate as pinnule tapers to tip. First pinnular with L/W = 1.1–1.7; next two pinnulars with L/W = 1.0–1.2; middle pinnulars with L/W ~ 4.0; slender distal pinnulars with L/W up to 5.3. Proximal several pinnulars with numerous spines on lateral margin facing arm tip. P2 up to 11 mm long with 21 segments; similar to P1 but more robust with fewer short proximal segments (e.g. in the holotype of Z. triserialis, the sixth pinnular of P1 is 0.5 mm long with L/W = 2.0, while that of P2 is 0.63 mm long with L/W = 3.8; but, at 4.0 mm from the base, P1 is 0.17 mm across and P2 is 0.25 mm across). P3 a genital pinnule. P4 up to 11.3 mm long, similar to preceding but with first two segments squarish and third longer than broad. Pa much shorter and more slender than P1. No middle or distal pinnules intact; the longest remaining attached to an arm fragment is 11.3 mm long with 18 segments [at least several segments missing; Clark & Clark (1967) indicate distal pinnules up to 15 mm]. Middle pinnules stiff and straight except near delicate tips, broader and flattened for more of their length than proximal pinnules, appearing more robust as a result. First pinnular short with diverging lateral margins; second longer but still wider than long, trapezoidal with converging lateral margins; third and following pinnulars abruptly narrower than second (but still flattened) and longer than wide; third to sixth or eighth pinnulars of about equal length, gradually becoming slightly narrower; L/W = 2.8 –4.0, increasing to 6.0 near pinnule tip; second pinnular with one or two strong spines at distal corner facing arm tip. Following pinnulars often bearing spine(s) at both distal corners. Distal pinnules similar but shorter and more slender. Disk naked, domed, with mouth central or subcentral; surface of tegmen level with br5–6. Colour. A. H. Clark (1921) recorded S. triserialis as deep purple wine-coloured (vinaceous); calyx and arm bases brownish. Distribution Geographic distribution. Tropical Indo-West Pacific Region from the Comoro Islands to New Caledonia, Wallis et Futuna and the Hawaiian Islands (Fig. 14). Bathymetric distribution. Of the seven stations with recorded depths, six fall within 460–769 m (possibly 351–809 m). One specimen is recorded as having been collected at 1395–1410 m. Remarks The previously published record of Sarametra includes only two specimens. Clark & Clark (1967) diagnosed the holotype 167 A revision of the Zenometridae • C. G. Messing & C. M. White of S. triserialis as having three columns of cirrus sockets per radial area, with numerous spines and obliterated sockets on the apical third of the centrodorsal (Fig. 4a); P1 and P2 each with 22 segments, 8 and 10 mm long, respectively. They described S. nicobarica as having three or four columns of cirrus sockets, no spines on the centrodorsal (Fig. 5b), and P1 and P2 with 17 and 15 segments, respectively. Comparison of the holotypes with additional specimens collected by a series of French and joint French–Indonesian expeditions indicates that the two nominal species form part of a growth series. All specimens have two columns of cirrus sockets apically. As the diameter of the centrodorsal increases, a third column is intercalated midradially. In the holotype of S. nicobarica, an irregular fourth column appears near the centrodorsal base ( Fig. 5b). Figure 6 superimposes the outlines of the centrodorsals of the two holotypes and four of the new specimens and also shows the levels at which the third and fourth columns of sockets first appear. The smallest specimen has two columns of sockets throughout; the third column appears only in the next larger specimen. Similarly, the fourth column of sockets appears in the holotype of S. nicobarica at a level wider than the basal diameter of the next smaller specimen, which has only three columns. The specimens vary in the development of spines on the centrodorsal apex and in the length and number of pinnulars composing P1 and P2, the tips of which are extremely fine and easily broken. S. nicobarica is treated as a synonym of S. triserialis herein. Three specimens differ somewhat from the pattern described above. The centrodorsal of MNHN EcCh 181 (Fig. 5a) is as tall as that of the holotype of S. nicobarica, but is substantially narrower at the base and bears only three columns of sockets per radial area with fewer functional sockets. The eroded appearance and partly concave profile of the apical half of the centrodorsal suggests possible resorption of skeletal material. MNHN EcCs 5232 and EcCs 5233 (Fig. 7b,c), omitted from the description above, differ from the others in having two columns of sockets per radial area at a size at which the others have three. Their centrodorsals have basal diameters of 2.8 and 3.0 mm; heights of 4.2 and 6.1 mm and H/D of 1.4 and 1.9. Both have proportionally fewer functional sockets; the cirri are XXXVIII and IIIL, up to 54 segments, 53 mm long. They are otherwise similar to the preceding and, because of the limited number of specimens available, are treated as conspecific. Genus Psathyrometra A. H. Clark, 1907a Psathyrometra A. H. Clark 1907a: 353 (part); Clark & Clark 1967: 510–511. Type species. Antedon fragilis A. H. Clark, 1907b 168 Other included species. Antedon bigradata Hartlaub, 1895; Antedon erythrizon A. H. Clark, 1907b; Psathyrometra congesta A. H. Clark, 1908. Diagnosis A genus of Zenometridae having the centrodorsal conical with straight or gently convex sides, H/D about 0.8 –1.5 and rounded or truncated apically. At least basal cirrus sockets separated interradially by narrow flat strip or weak interradial ridge; ridge, when present, no longer than long axis of basal-most cirrus socket. Cirrus socket margins often coarsely crenulate; concave fulcral stereom spreading to lateral margins of sockets. Distal cirrals elongated and tapering; opposing spine weak or absent. Basals broad and tongue-like interradially with a pair of interior openings surrounded by stereom that corresponds to a rosette. Proximal ray ossicles smooth, bearing very fine spinules, or with cluster of small spines restricted to projecting tips of synarthrial tubercles. First segment of P1 with L/W at least 2.0. Additional characters. Cirrus sockets in two to four columns per radial area. Aboral pole ranging from convex or dome-like to flat or excavated. Distal segments of proximal pinnules extremely slender and elongate except for short terminal three. Distribution Geographic distribution. Hawaiian Islands and the Pacific Rim from the Galapagos Islands and Panama to southern Japan ( Fig. 14). Bathymetric distribution. 439–2903 m (possibly as shallow as 197 m). Of the 12 published depth records, eight are about 1000 m or shallower (chiefly 700–1000 m) and include all records of P. bigradata, P. erythrizon and P. congesta; three records fall between 1200 and about 1900 m, and a single record exists from 2903 m. Remarks This re-diagnosis omits four species formerly included in Psathyrometra: P. mira A. H. Clark, P. minima A. H. Clark, P. anomala A. H. Clark and P. gracillima A. H. Clark. Examination of two specimens of P. mira ( USNM 27508, BMNH 1937.2.25.25) and a published figure of P. minima (Clark & Clark 1967: 526) indicates the absence of the characteristic zenometrid cirrus sockets. In P. mira, P. anomala and P. gracillima, at least the first segment of P1 is short (the pinnules are unknown in P. minima). All four apparently lack externally visible basals. These four species are removed herein to Athrypsometra gen. nov. (see below) in the family Antedonidae, although it remains unclear if they belong in a single genus. Because little additional material of Psathyrometra has been collected since Clark & Clark (1967) last described the known Zoologica Scripta, 30, 3, July 2001, pp159 – 180 • © The Norwegian Academy of Science and Letters C. G. Messing & C. M. White • A revision of the Zenometridae Fig. 8 A–D. Psathyrometra fragilis, centro- dorsals and ray bases in radial view. —A. USNM 35739 (type locality). —B. USNM 35784. —C. USNM 22613 (holotype of P. erythrizon). —D. USNM 35787. Scale: 1 mm. species, the following diagnoses and descriptions are chiefly supplementary. Psathyrometra fragilis (A. H. Clark, 1907b) (Figs 1a,b, 2c, 8, 9d, 10a) Antedon fragilis A. H. Clark 1907b: 80. Antedon erythrizon A. H. Clark 1907b: 79. Psathyrometra fragilis: A. H. Clark 1907a: 353; 1915: 241 (fig. 209), 301 (fig. 379), 369 (fig. 502), 375; 1921: 61-63 (figs 91, 92), 77, 271, 281, 292, 299, 300, 373, 724, 729; Clark & Clark 1967: 512–515. Psathyrometra erythrizon A. H. Clark 1907a: 353; 1915: 241 (figs 212, 213); Clark & Clark 1967: 518 –519; Kogo 1998: 133–134, fig. 109. Psathyrometra borealis A. H. Clark 1908: 236; 1915: 176 (fig. 110), 241 (fig. 211); 1921: 271, 281, 292. Psathyrometra profundorum A. H. Clark 1908: 237; 1915: 241 (fig. 210). Psathyrometra alascana A. H. Clark (1918): 223, 226. Psathyrometra fragilis forma fragilis Clark & Clark 1967: 511. Psathyrometra fragilis forma borealis Clark & Clark 1967: 511, 515. Material examined. JAPAN: USNM 35739 (holotype of A. fragilis), ‘Albatross’ sta. 5032, Yezo Strait, between Yezo © The Norwegian Academy of Science and Letters • Zoologica Scripta, 30, 3, July 2001, pp159 – 180 and Kunashir, Kuril Is., 44°04′ N, 145°30′ E, 548–974 m, 30 September 1906; USNM 22613 (holotype of A. erythrizon), ‘Albatross’ sta. 4981, Benkei Misaki, Hokkaido I., 42°58′15″ N, 140°09′10″ E, 713–743 m, 19 September 1906; USNM 35657 (1 specimen, P. erythrizon), ‘Albatross’ sta. 4981, Benkei Misaki, Hokkaido I., Sea of Japan, 42°58′15″ N, 140°09′10″ E, 713–743 m, 19 September 1906. ALASKA: USNM 22670 (holotype of P. borealis), ‘Albatross’ sta. 4780, NE Agattu I., Aleutian Is., 52°01′ N, 174°39′ W, 1813 m, 7 June 1906; USNM 35787 (11), ‘Albatross’ sta. 4230, Behm Canal, Naha Bay, Revillagigedo I., Alexander Archipelago, 55° N, 131° W, 198–439 m, 7 July 1903. CANADA: USNM 35742 (1), ‘Albatross’ sta. 3342, Queen Charlotte Is., British Columbia, 52°39′30″ N, 132°38′ W, 2903 m, 3 September 1890. CALIFORNIA: USNM 35784 (28 of 57 specimens measured), ‘Albatross’ sta. 4537, Point Pinos, Monterey Bay, 36°45′ N, 121°55′ W, 1575–1942 m, 31 May 1904. GULF OF PANAMA: USNM E51600 (2), UMML 44.230 (1) ‘Gilliss’ sta. 22, 07°28′ N, 79°12′ W, 741– 823 m, 18 January 1972. Diagnosis A species of Psathyrometra with centrodorsal H/D = 0.78– 1.53 (rarely less than 0.90, see below); cirrus sockets separated interradially by narrow flat strip with short basal interradial ridge ranging from low but distinct to almost non-existent. 169 A revision of the Zenometridae • C. G. Messing & C. M. White Fig. 9 A–D. Psathyrometra spp., centrodorsals and ray bases in radial view. — A. P. congesta, USNM 22684 (holotype). —B. P. bigradata, USNM E51614. —C. P. bigradata ( plate 1, fig. 5 from Hartlaub 1895). —D. P. fragilis, UMML 44.230. Scale: (lower right) A, B, D = 1 mm. Scale: ( lower left) C ~ 2 mm. ( Note: the centrodorsal in Hartlaub’s original figure is 18 mm across the base; his legend indicates × 3, from which the scale at lower left is calculated.) Distal end of oral margin of middle and mid-distal cirrals often extended distally as triangular spine (visible in oral view); penultimate cirral squarish with weak opposing spine. Axil and br2 with concave proximolateral margins, smooth aborally or with very fine spinules. Proximal brachials with moderately or well-developed alternating articular tubercles. Distal midaboral margins of middle and distal brachials smooth. Description Centrodorsal truncated conical, 2.7–5.7 mm across the base [6.1 mm in a specimen described by Kogo (1998) ], 2.9 – 7.7 mm tall; H/D usually 0.92 –1.53 (0.78–0.85 in specimens formerly attributed to P. erythrizon; 0.84–0.94 in Gulf of Panama specimens). Aboral pole ranging from convex to flat or excavated; sometimes bordered with weak eroded spines or papillae. Cirrus sockets crowded or well separated, in three or four columns per radial area with three to six sockets per column, occasionally reduced to two columns near the 170 apex, separated interradially by narrow flat strip. Four columns, when present, restricted to broader basal portion of centrodorsal. Short basal interradial ridge ranging from low but distinct to almost non-existent. Functional cirri approximately LIV–CXII (including immature peripheral cirri), 33 (few complete), up to 67 mm long; XLIII in a small specimen identified as P. erythrizon ( USNM 35657). Middle cirrals with L/W up to 5.0, compressed, expanded distally, and with the oral distal margin sometimes projecting distally as a triangular spine (visible in oral view), sometimes finely denticulate. Antepenultimate cirral with L/W = 1.25 –1.3; penultimate cirral with L/W = 1.0–1.2, bearing a small, distally pointed opposing spine; terminal claw slightly curved. Basals visible externally as inflated pentagonal extensions of interradial ridges of centrodorsal, often extending laterally as extremely narrow strip in deep subradial clefts; adjacent basals may or may not meet midradially in external view. Zoologica Scripta, 30, 3, July 2001, pp159 – 180 • © The Norwegian Academy of Science and Letters C. G. Messing & C. M. White • A revision of the Zenometridae Fig. 10 A–D. Psathyrometra spp., cirrus tips. —A. P. fragilis, USNM 35784, peripheral. —B–D. P. bigradata. —B. USNM E51616, peripheral. —C. Same, apical. —D. USNM E51615, apical. Scale: 1 mm. Radials short. Combined profile of radial and Ibr1 slightly convex to slightly concave. IBr2 and br1–2 with strong synarthrial tubercles. IBr2 axil and br2 with concave proximolateral margins; smooth or with very fine spinules at midaboral apex (occasionally with traces of apical spines). Arms 10, none complete; R = +100 mm. Diameter of br3+4 1.4–2.8 mm. Proximal brachials with moderately or well-developed alternating articular tubercles. Distal aboral margins of middle and distal brachials smooth. [See Clark & Clark (1967) for descriptions of pinnules.] Distribution Geographic distribution. Pacific Rim from southern Japan northward to the Aleutian Islands and southward to Monterey Bay, California (Clark & Clark 1967); Gulf of Panama. Bathymetric distribution. 439 ( possibly 197) to 2903 m (Clark & Clark 1967). Remarks Clark & Clark (1967) distinguish P. fragilis f. fragilis (four columns of sockets per radial area; found at 439–974 m) from P. fragilis f. borealis (three columns; 1210 –2903 m). However, the two overlap both morphologically and distributionally. At a single station (Alaska; USNM 35787), specimens identified © The Norwegian Academy of Science and Letters • Zoologica Scripta, 30, 3, July 2001, pp159 – 180 as P. fragilis f. fragilis by A. H. Clark have either three or four columns of sockets. As in S. triserialis, column number appears to increase with size, at least to some degree. On the other hand, the centrodorsals of specimens from Japan, Alaska and Canada are generally shorter and have more sockets (which appear more crowded) for a given basal diameter or height than those from California (Figs 11, 12). However, because P. fragilis has only been collected at five localities between Japan and Canada, and at only one station off California, the morphological variations observed between regions may not accurately reflect true geographical, environmental or taxonomic trends. The three specimens from the Gulf of Panama differ somewhat from the other specimens of P. fragilis and approach P. bigradata and P. erythrizon. Two of the Panama specimens resemble the latter two species in having proportionally shorter centrodorsals (H/D = 0.84 and 0.90) than any ‘typical’ P. fragilis (that is, as construed by Clark & Clark 1967). All three resemble P. erythrizon in having fewer cirrus sockets both for a given centrodorsal diameter and for a given H/D ratio than any ‘typical’ P. fragilis (Figs 11b, 12b). Finally, they were collected outside the known range of P. fragilis and within that attributed to P. bigradata (see below). However, one of the Panama specimens has an H/D ratio (0.94) within the range found in ‘typical’ P. fragilis (≥ 0.92), and all three resemble P. fragilis in all other respects (although lacking cirri and arms beyond br3). According to Clark & Clark (1967), P. erythrizon, known only from Japanese waters, has a proportionally shorter centrodorsal than P. fragilis, and has three columns of cirrus sockets per radial area, whereas P. bigradata and P. congesta have four. However, similar variation in the number of columns of sockets among ‘typical’ P. fragilis reduces the diagnostic usefulness of this trait. P. bigradata and P. congesta exhibit other diagnostic features described below. In specimens attributed to P. erythrizon [i.e. the holotype, a small specimen (USNM 35657) and one described and figured by Kogo (1998)], H/D ratios are indeed lower (0.78 – 0.85) than in any ‘typical’ P. fragilis (Fig. 12b). However, the holotype is almost identical to the largest specimen from the Gulf of Panama (compare Figs 8c and 9d). In the Gulf of Panama specimens, the holotype of P. erythrizon and Kogo’s (1998) figure, functional sockets and the bare interradial strip extend from the base to the apex of the centrodorsal. An apical portion with obsolete sockets and poorly defined interradial strip characteristic of ‘typical’ P. fragilis (Fig. 8a,b,d) is absent. Such an apex would generate a greater H/D ratio, rendering these specimens indistinguishable from ‘typical’ P. fragilis (i.e. moving them from left to right in Fig. 12b). Resorption or erosion of the centrodorsal apex is widespread among comatulids (including Z. columnaris and various antedonids), especially in larger and, ostensibly, older specimens. Two of the 171 A revision of the Zenometridae • C. G. Messing & C. M. White Fig. 11 A,B. Psathyrometra spp. Graph of centrodorsal midradial height (A) and basal diameter ( B) plotted against number of functional cirrus sockets. (m) P. fragilis from Japan, Alaska and Canada. (d) P. fragilis from California. (s) P. fragilis from the Gulf of Panama. (h) P. ‘erythrizon’. (e) P. bigradata from the Galapagos Is. (+) P. congesta (holotype). The three specimens of P. erythrizon are the holotype, the small specimen ( USNM 35657) and the specimen described by Kogo (1998). Gulf of Panama specimens, the holotype of P. erythrizon and Kogo’s (1998) figured specimen have among the largest centrodorsals of any measured specimen of Psathyrometra. As a result, given the range of morphological variation outlined above, the appearance of extremely similar specimens at opposite ends of the known geographical range ( Japan and the Gulf of Panama), and the location of the only known specimens of P. erythrizon within the geographical and bathymetric range of P. fragilis, both P. erythrizon and the specimens from the Gulf of Panama are treated as P. fragilis herein. Psathyrometra bigradata (Hartlaub, 1895) (Figs 9b,c, 10b–d) Antedon bigradata Hartlaub 1895: 145, pl. 1, fig. 5. Psathyrometra bigradata A. H. Clark 1907b: 353; Clark & Clark 1967: 515–517. 172 Material examined. GALAPAGOS IS: USNM E51614 (1), ‘Johnson Sea-Link II’ 3100, Cabo Douglas, Fernandina I, 00°17′24″ S, 091°39′00″ W, 612 m, 16 July 1998, Baldwin, C., Pawson, D.L., colls.; USNM E51615 (1), ‘Johnson Sea-Link II’ 3101, Cabo Douglas, Fernandina I, 00°17′30″S, 091°39′36″ W, 740 m, 17 July 1998, Pawson, D.L., Merlen, G., colls.; USNM E51616 (1), ‘Johnson Sea-Link II’ 3108, Marchena I., 00°24′00″ N, 090°26′30″ W, 484 m, 21 July 1998, Pawson, D. L., coll. Diagnosis A species of Psathyrometra with centrodorsal H/D = 0.80– 0.84; cirrus sockets separated interradially by narrow flat strip; interradial ridges absent. Distal end of oral margin of middle and mid-distal cirrals finely denticulate, straight or convex in oral view; penultimate cirral longer than wide, Zoologica Scripta, 30, 3, July 2001, pp159 – 180 • © The Norwegian Academy of Science and Letters C. G. Messing & C. M. White • A revision of the Zenometridae Fig. 12 A,B. Psathyrometra spp. Graph of (A ) centrodorsal basal diameter plotted against centrodorsal midradial height and (B ) centrodorsal height/diameter (H /D) plotted against number of functional cirrus sockets. Symxbols as in Fig. 11. tapered, with opposing spine absent in fully developed cirri of large specimens. Axil and br2 with proximolateral margins gently concave to almost straight, with tuft of spines at tips of synarthrial tubercles. Proximal brachials with alternating articular tubercles weak or absent. Distal midaboral margins of middle and distal brachials spinose. Description Centrodorsal convex conical, wider than tall, 3.4–5.0 mm across, 2.9– 4.0 mm tall; H/D = 0.80 –0.84. Aboral pole flat, irregularly convex or subcylindrical, sometimes rimmed with eroded spines or fused papillae. Cirrus sockets in three or four columns per radial area peripherally, narrowing to two or three columns apically. Peripheral sockets project outwards from deep subradial clefts. Columns of sockets © The Norwegian Academy of Science and Letters • Zoologica Scripta, 30, 3, July 2001, pp159 – 180 separated interradially by narrow flat strip; interradial ridges absent (although flat strip may be slightly inflated adjacent to basals). Functional cirri ~ LV–LXX, 25– 35, 39 – 74 mm long. Middle cirrals with L/W up to 4.3, compressed, expanded distally, with distal oral margins convex or straight in oral view and finely denticulate. Antepenultimate cirral with L/W = 2.0; penultimate cirral longer than wide and tapered, L/W = 1.4 –1.6; opposing spine absent in fully developed cirri [present but small and weak in small specimen (USNM E51615); a trace or swelling present on apical cirri of large specimens]; terminal claw slightly curved. Radials short. Combined profile of radial and Ibr1 concave. IBr2 and br1–2 with strong synarthrial tubercles. Ibr2 axil and br2 with W/L ~ 1.0, sometimes with fine midaboral spinules; 173 A revision of the Zenometridae • C. G. Messing & C. M. White proximolateral margins concave or straight; projecting midaboral tips of synarthrial tubercles with tuft of spines (sometimes also on Ibr1). Arms 10; R ~ 85–165 mm. Diameter of br3+4, 1.5 – 2.5 mm. Proximal brachials with alternating articular tubercles weak or absent. Distal aboral margins of middle and distal brachials spinose. P1 of 20 segments, 14.5 mm long; L/W of first pinnular up to 2.7; fine spinules along lateral margin of pinnulars facing arm tip apparently more abundant and dense than in P. fragilis. Middle pinnule with 28 segments, 20.5 mm long; the first two pinnulars short; following pinnulars longer than wide, compressed, of similar length to near pinnule tip; distal pinnulars shorter. written description is based on the other specimen; Hartlaub does not specify. Although the Galapagos specimens cluster with the low-H/ D P. fragilis (i.e. P. ‘erythrizon’ and Gulf of Panama specimens) separately from ‘typical’ P. fragilis (Fig. 12b), the combined characteristics of the centrodorsal, cirri (Figs 8 –10), brachitaxes and proximal brachials described above still distinguish the Galapagos specimens from all other Pacific Rim Psathyrometra. Of course, additional material, particularly from areas between known localities (e.g. the Cocos Ridge or coast of Mexico), may alter this perception. Distribution Geographic distribution. Galapagos Islands and (possibly) Gulf of Panama. Psathyrometra congesta A. H. Clark 1908: 213, 221; 1915: 241 (fig. 208); Clark & Clark 1967: 517. Bathymetric distribution. 484– 740 m (possibly to 1016 m; Hartlaub 1895). Remarks The preceding diagnosis and description are based on three specimens recently collected in the Galapagos Is. The material on which Hartlaub (1895) based his original description (Galapagos Is., ‘Albatross’ sta. 3404, 01°03′00″ S, 89°28′00″ W, 704 m, 28 March 1891, 1? specimen; off Punto Mariato, Panama, ‘Albatross’ sta. 3358, 06°30′00″ N, 81°44′00″ W, 1016 m, 24 February 1891, 1? specimen) has apparently been lost. The holotype is not included among echinoderm type specimens listed for the Museum of Comparative Zoology, Harvard (C. H. Felton & R. M. Woollacott, unpublished), and Deichmann reports (in Clark & Clark 1967) that it is missing as well. Clark & Clark (1967) give no catalogue number or location for the other specimen, indicating that they never saw it. Unfortunately, Hartlaub’s original description (1895: 145) and figure are not detailed enough to identify his specimens to species, although they appear to be Psathyrometra s. s. His description of the centrodorsal could apply to P. fragilis: [‘ziemlich lang conisch, mit abgestumpfter Spitze und etwas gewölbten Seiten’ (‘moderately long conical, with a truncated tip and somewhat vaulted sides’); about 80 deep cirrus sockets in five ‘fields’ separated by narrow interradial strips, with four columns of four sockets in each field], although the ‘somewhat vaulted sides’ applies more to the new Galapagos material. Clark & Clark (1967) drew their measurements of the centrodorsal of P. bigradata from Hartlaub’s figure: 6 mm across the base and 5 mm tall. However, unlike the description, the figure (reproduced here as Fig. 9c) clearly shows five columns of cirrus sockets with up to six sockets per column, suggesting either that the figure is not accurate or that the 174 Psathyrometra congesta A. H. Clark, 1908 (Fig. 9a) Material examined. USNM 22684 (holotype), ‘Albatross’ sta. 3992, Kaweonui Point, Kauai I., Hawaii, 22°15′50″ N, 159°29′55″ W, 966 m, 12 June 1902. Diagnosis A species of Psathyrometra having the centrodorsal truncated, convex conical and wider than tall (H/D = 0.79), with four crowded columns of cirrus sockets narrowing to two or three apically. Only peripheral sockets separated interradially by a short, weak ridge; middle and apical sockets not separated interradially. Ibr1 with a midaboral tuft of spines; Ibr2 axil and br2 with fine midaboral spinules. Description Centrodorsal truncated conical with convex sides; basal diameter 4.9 mm, height 3.9 mm; H/D = 0.79. Aboral pole flat and very slightly excavated. Tops of basal-most sockets project out from deep subradial clefts bridged laterally by weak interradial ridges and swollen pentagonal basals. Basals forming complete narrow circlet visible in floor of subradial clefts. Radials very short, with corners swollen over basals. Combined profile of radial and Ibr1 strongly concave. Ibr1 and br1 deeply incised distally by elongated synarthrial projections of axil and br2. Axil rhombic with concave margins. Both ossicles of IBr2 series with fine midaboral spinules (also on br2), stronger on Ibr1. Arms broken at br3; diameter at br3+4, 2.3 mm. Broken arm fragments with proximal brachials triangular, W/L = 1.6; following brachials becoming cuneate with W/L = 1.1–1.2; distal brachials with W/L = 0.8. Distal aboral margins all smooth. Syzygial interval 3 –6 (chiefly 3–4). Proximal pinnules all broken, but proximal segments compressed, with L/W ~ 2.0, and with numerous fine short spinules along lateral margins facing aboral surface of arm. Zoologica Scripta, 30, 3, July 2001, pp159 – 180 • © The Norwegian Academy of Science and Letters C. G. Messing & C. M. White • A revision of the Zenometridae Distribution Known only from the type locality: off Kauai I., Hawaii, 966 m. unclear whether these four taxa form a monophyletic group. They are not assigned to subfamily here. Phylogeny of the Zenometridae Remarks The distinct arrangement of cirrus sockets (Figs 9a, 11a) and disjunct distribution of P. congesta support maintaining it as a separate species. Family ANTEDONIDAE Athrypsometra gen. n. Type species. Psathyrometra mira A. H. Clark, 1909b. Other included species. P. gracillima A. H. Clark, 1909c; P. minima A. H. Clark, 1912; P. anomala A. H. Clark, 1912. Material examined. PHILIPPINES: USNM 27508 (1, Psathyrometra mira), ‘Albatross’ sta. 5284, 13°42′05″ N, 120°30′45″ E, 771 m, 20 July 1908. ZANZIBAR: BMNH 1937.2.25.25 (1, Psathyrometra mira), ‘Mahabiss’ sta. 109, 05°10′36″ S, 39°33′48″ E, 640 m. Etymology. Athrypsometra is an anagram of Psathyrometra loosely derived from a-, used in the sense of ‘away’, and thrypsis, a breaking, because members of this genus have been broken away from Psathyrometra. Diagnosis A genus of Antedonidae with a conical centrodorsal as wide across the base as tall, or wider; two columns of cirrus sockets per radial area separated by interradial spaces. Cirrus sockets shallow, almost flush with centrodorsal surface, not bowl-like. Basals sometimes visible as flat interradial triangles. Aboral surface of brachitaxes flattened; synarthrial projections absent; proximal segments of proximal pinnules short or squarish. Remarks The lack of diagnostic cirrus sockets and proximal pinnules clearly places these species outside the Zenometridae. The segregation of columns of sockets into radial areas separated by interradial spaces distinguishes them from the other former zenometrines except Balanometra. However, in Balanometra, the columns of sockets are separated interradially by a broad furrow, the centrodorsal margin undulates (concave interradially and midradially; convex over each peripheral cirrus socket) and the radials form a narrow continuous band so closely fused to the centrodorsal that the suture is indistinct. [Clark & Clark (1967) incorrectly describe the radials as concealed by the centrodorsal.] Nevertheless, it remains © The Norwegian Academy of Science and Letters • Zoologica Scripta, 30, 3, July 2001, pp159 – 180 To gain some understanding of the phylogenetic relationships among the three putative zenometrid genera, a cladistic analysis of 27 characters was performed using PAUP* 4.0b4 and MacClade 3.07 on a Power Macintosh G3. With the exception of Milsom et al.’s (1994) examination of the relationships among the aberrant fossil genera Marsupites and Uintacrinus and several comatulids, White et al.’s (2000) molecular phylogeny of comasterid genera and Rankin’s (2000) cladistic analysis of the genera Stephanometra and Lamprometra, phylogenetic relationships among comatulid groups are unknown and untested at all hierarchical levels. Because comatulid morphology has yet to be examined in detail from a phylogenetic standpoint, the identification of appropriate sister and outgroups is uncertain. In order to test the monophyly of the proposed Zenometridae, the five putative zenometrid species were compared with Poliometra prolixa, an antedonid formerly included within the Zenometrinae (on the basis of the columnar arrangement of its cirrus sockets) and a potential sister group taxon, Florometra serratissima, an antedonid from another nominal subfamily, the Heliometrinae, and Oceanometra annandalei, a member of the Thalassometridae, which is currently placed in the superfamily Tropiometracea (Rasmussen & Sieverts-Doreck 1978). Both Zenometra and Sarametra are currently monotypic. Both P. bigradata and P. congesta include missing data because the few known specimens could not be dissociated for examination of internal structure, and the only known specimen of P. congesta lacks cirri. The 27 characters used in the analysis, 10 of which are multistate, derive from all major skeletal components (i.e. centrodorsal, cirri, calyx and rays). All characters are unweighted and unordered. An exhaustive search (using the ACCTRAN option for character state optimization) was run using the maximum parsimony criterion. The data were re-sampled using the branch and bound bootstrap option (2500 replicates) in order to provide statistical support for the tree nodes. The characters and their states are listed in Table 1 with each of the 19 informative characters indicated by an asterisk (Table 2 shows the character state matrix.). A single most parsimonious tree topology (tree length = 54) (Fig. 13) is recovered. Statistical indices indicate a high level of confidence (CI = 0.96; RI = 0.94; RC = 0.90). Bootstrap re-sampling supports the following: a Z. columnaris/ S. triserialis clade at 84%; a monotypic Psathyrometra at 93%; the Zenometridae (Psathyrometra(Z. columnaris/S. triserialis)) at 100%; and a F. serratissima/P. prolixa clade at 90%. In addition, Bremer’s (1994) ‘branch support’ indices (‘decay indices’; 175 A revision of the Zenometridae • C. G. Messing & C. M. White Table 1 List of characters and character states (*denotes informative characters). 1 *Centrodorsal wall: (0) thick, i.e. approximately equal to central cavity diameter; (1) thin, i.e. central cavity distinctly wider than thickness of surrounding wall A. H. Clark (1931) used the relative size of the cavity as a primary character distinguishing the comatulid suborders Oligophreata (small cavities) and Macrophreata (large cavities), although Gislén (1924) dismissed its usefulness at this level to taxonomic and ontogenetic variability 2 *Oral lip of centrodorsal cavity: (0) absent; (1) present 3 Centrodorsal shape: (0) hemispheric; (1) conical; (2) cylindrical 4 *Centrodorsal interradial space: a narrow longitudinal strip that segregates adjacent cirrus sockets into radial areas: (0) absent; (1) short, no more than about height of most peripheral socket; (2) well developed and often extending to aboral pole, or nearly so 5 *Centrodorsal interradial ridges: (0) absent; (1) weak, restricted to centrodorsal periphery; (2) moderate or strong, at least a third of the centrodorsal height 6 Centrodorsal radial space: similar to number four, but typically triangular and midradial: (0) absent; (1) present 7 *Ratio of centrodorsal height to diameter (H/D): (0) much less than 0.8; (1) ~ 0.8–0.9; (2) 0.9–1.0; (3) much greater than 1 8 *Centrodorsal aboral pole: (0) convex; (1) conical; (2) flat; (3) excavated 9 Obsolete apical cirrus sockets: (0) present; (1) absent 10 Arrangement of cirrus sockets: (0) crowded; (1) columns As noted in the text, cirrus sockets in all comatulids exhibit a basically bispiral arrangement. However, they can be aligned as well in distinct columns along the oral/aboral axis 11 *Fulcral stereom of cirrus sockets: (0) raised; (1) concave In the majority of comatulids, cirrus sockets bear a raised mound consisting of stereom with relatively few small pores surrounding the central lumen. In most cases, the most prominent part of the mound is a pair of low knobs flanking the lumen that apparently serves as the actual fulcrum. In putative zenometrids, the fulcral stereom forms a distinctly concave bowl rather than a raised or convex mound 12 *Fulcral bowl of cirrus sockets: (0) absent; (1) surrounding central lumen; (2) spread to lateral margins of socket 13 *Marginal crenulations of cirrus sockets: (0) absent; (1) coarse; (2) fine 14 *Distal cirrals: (0) shorter than wide; (1) elongated, i.e. much longer than wide 15 *Cirrus tip: (0) not tapered; (1) tapered 16 Opposing spine: (0) present; (1) reduced or absent 17 *Penultimate cirral: (0) short; (1) square; (2) longer than wide and tapered 18 *Basal ossicle circlet: (0) reduced; (1) complete In the majority of comatulids, the basal circlet is modified and reduced after loss of the postlarval stalk to form a delicate central plate called the rosette. It may or may not be accompanied by interradial rods called basal rays that may or may not be visible from the exterior. As noted in the text, the basals of zenometrids form a complete circlet, although they are less well developed than the circlet-forming basals of Atelecrinidae 19 *Basal rosette: (0) discrete; (1) fused; (2) reduced; (3) absent A discrete rosette is a single decagonal central ossicle with a small central perforation; it lacks attachment to interradial processes or basal rays. In Psathyrometra, the stereom surrounding the openings for nerve cords at the inner end of the basal ossicle corresponds to the radial and interradial processes of a discrete rosette, but is broadly fused to the wide tongue-like basal. In P. prolixa, a small remnant of rosette stereom appears to extend inwards from the interior aboral angle of the radials where the paired median canals open. In Z. columnaris and S. triserialis, the inner rosette stereom is absent 20 *Interradial processes of basal ossicles: (0) absent; (1) broad, i.e. about as long as wide; (2) narrow, i.e. distinctly longer than wide 21 *Long fine spines webbed with tissue on proximal brachials: (0) absent; (1) present Spines may be present on the proximal brachials in both F. serratissima and O. annandalei, but they are not as long or fine as in Z. columnaris or S. triserialis 22 *Midaboral spines on synarthrial apex: (0) absent; (1) fine spinules; (2) tuft 23 *Midaboral spines on distal brachials: (0) absent; (1) present 24 Location of second arm syzygy: (0) br9+10; (1) distal to br9+10 25 *Length to width ratio (L/W) of basal pinnulars of proximal pinnules: (0) wider than long; (1) as long as wide to twice as long as wide; (2) twice as long as wide or longer 26 *Pinnule cross-section: (0) prismatic (triangular); (1) round; (2) compressed 27 Ambulacral side and covering plates: (0) absent; (1) present Table 2 Character matrix (eight taxa by 27 characters) used in the cladistic analysis of the Zenometridae. Character and character state data are given in Table 1. Species 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Oceanometra annandalei Florometra serratissima Poliometra prolixa Psathyrometra fragilis Psathyrometra bigradata Psathyrometra congesta Sarametra triserialis Zenometra columnaris 0 0 0 1 ? ? 1 1 1 1 1 0 ? ? 0 0 1 0 1 1 1 1 1 2 0 0 0/1 2 2 1 2 2 0 0 0 1 0/1 1 2 2 1 0 0 0 0 0 0 0 0/1 0 1/2 1/2/3 1 1 3 3 0 0 0 0/2/3 0/2 2 0/1 2/3 0 1 1 0/1 1 1 1 1 1 0 1 1 1 1 1 1 0 0 0 1 1 1 1 1 0 0 0 2 2 ? 1 1 1 0 0 1 1 ? 2 2 0 0 0 1 1 ? 0 0 0 0 0 1 1 ? 0 0 1 1 1 1 0 ? 1 1 0 0 0 1 1 ? 0 0 0 0 0 1 1 1 1 1 0 0 2 1 ? ? 3 3 0 0 0 1 1 1 1 2 0 0 0 0 0 0 1 1 0 0 0 0/1 1/2 1 0 0 1 0 0 0 1 0 1 1 1 0 0 0 0 0 0 0 0 0 0 2 2 2 1 2 0 1 1 2 2 2 2 2 1 0 0 0 0 0 0 0 176 Zoologica Scripta, 30, 3, July 2001, pp159 – 180 • © The Norwegian Academy of Science and Letters © The Norwegian Academy of Science and Letters • Zoologica Scripta, 30, 3, July 2001, pp159 – 180 Labels indicate character numbers and state transformations corresponding to those given in Table 1. Open bars with italicized labels indicate homoplasies. 177 C. G. Messing & C. M. White • A revision of the Zenometridae Fig. 13 Cladogram of the relationships among Psathyrometra, Sarametra, Zenometra, Poliometra, Florometra and Oceanometra. Tree length = 54 steps; CI = 0.96; RI = 0.94; RC = 0.90. A revision of the Zenometridae • C. G. Messing & C. M. White Fig. 14 Distributions of Zenometra (j), Sarametra (d) and Psathyrometra (w) as defined herein. Records for Zenometra and Sarametra are given in the text. Records for Psathyrometra are from Clark & Clark (1967), Kogo (1998) and the text. Donoghue et al. 1992) indicate that the Florometra/Poliometra, Psathyrometra and Sarametra/Zenometra clades collapse one step away from the most parsimonious tree, while the Zenometridae requires five additional steps before collapse. These analyses clearly support the monophyly of the Zenometridae. Although the F. serratissima/P. prolixa clade reflects a separate monophyletic Antedonidae, these two genera represent only a small percentage of the 48 nominal genera in the family, so its stature as a monophyletic group must remain tentative. Within the Zenometridae, a P. fragilis/P. congesta clade is only weakly supported (74%). We maintain Zenometra and Sarametra as distinct genera despite their monotypy on the basis of: (i) substantially lower support for the Z. columnaris/ S. triserialis clade (84%) relative to Psathyrometra (93%); (ii) their geographical separation; and (iii) distinctly narrower basals in Z. columnaris relative to the broad basals shared by S. triserialis and P. fragilis. Biogeography supports the Z. columnaris/S. triserialis clade within the Zenometridae (Fig. 14). Most records of both taxa are tropical or subtropical at bathyal depths (chiefly < 1000 m); the former is Atlantic and the latter Indo-West Pacific, a distribution consistent with a Tethyan origin for their common ancestor. Four published temperature records range from 5.83 °C (possibly 5.72) to at least 12.11 °C (Clark & Clark 1967). Psathyrometra, by contrast, chiefly occurs around the northern Pacific Rim in water colder than 7 °C [published range: 0.39– 6.61 °C (Clark & Clark 1967) ]. Although bottom temperatures were probably not taken at precisely the same location and depth as dredge samples at a given station on sloping bottoms a century ago, the data suggest that Z. columnaris and S. triserialis generally occur in warmer water than Psathyrometra. The single anomalously deep record of Z. columnaris from the eastern Atlantic is inconsistent with the other records 178 of the species and those of S. triserialis, but does conform to the pattern of deeper eastern records for other amphi-Atlantic comatulids (Pentametrocrinus atlanticus and Trichometra cubensis). Sarametra triserialis and Psathyrometra congesta both occur in the Hawaiian Islands, but their records here (a single specimen of each) are separated by at least 300 m. Similar depth differences separate strongly distinct crinoid assemblages elsewhere (Messing 1985; Bourseau et al. 1988; Bourseau & Roux 1989). Florometra serratissima and its probable synonym, F. asperrima, occupy about the same range as P. fragilis — northern Japan to Baja California — but range into much shallower water. Monotypic P. prolixa occurs from Greenland east to Siberia and as far south as the Faeroe Channel (Clark & Clark 1967; A. M. Clark 1970). O. annandalei is known from the Philippines and eastern Indonesia (Messing et al. 2000). With respect to lifestyle, S. triserialis (MNHN EcCs 5233) was collected clinging to an isidid alcyonarian. Z. columnaris has similar cirri and may share this clinging habit, but its cirri are rarely retained. The tapered, non-prehensile cirri of Psathyrometra reflect a distinctly different substrate preference (i.e. sediment, gravel or rock). Zenometrids also share several character states with members of the Atelecrinidae: (i) cavernous centrodorsal cavity; (ii) basals often broad and forming a complete circlet; (iii) horseshoe-shaped rims on some cirrus sockets in S. triserialis; and (iv) elongated basal pinnulars on proximal pinnules. However, it is not clear that any of these are homologous in the two families. The zenometrids lack the blind interradial pockets recently found in the centrodorsals of Atelecrinus (Messing 2000). Broad zenometrid basals may bear an interior rosette-like arrangement (Fig. 2c), but lack the interior paired prongs of atelecrinid basals (Fig. 2d). Finally, the horseshoe-shaped rim characteristic of atelecrinid cirrus Zoologica Scripta, 30, 3, July 2001, pp159 – 180 • © The Norwegian Academy of Science and Letters C. G. Messing & C. M. White • A revision of the Zenometridae sockets extends inward to the socket lumen unlike the narrow rim in S. triserialis. Some of these features may be paedomorphic. Juvenile comatulids tend to possess a proportionally larger centrodorsal cavity (A. H. Clark 1915: 234) and longer basal pinnulars. Also, a complete basal circlet metamorphoses into the rosette during early ontogeny (Breimer 1978). As noted above, comatulid morphology must be re-examined in detail before more robust phylogenetic hypotheses can be offered. Acknowledgements We wish to gratefully thank David Pawson (Smithsonian Institution), Nadia Ameziane (Muséum National d’Histoire Naturelle, Paris) and Sheila Halsey (British Museum of Natural History, London) for permitting us to work in their laboratories and have access to specimens in the collections at their respective institutions. We also wish to thank Nancy Voss (Rosenstiel School of Marine and Atmospheric Science, University of Miami) for permitting us to examine specimens in the R.S.M.A.S. invertebrate collection. Cynthia Ahearn (Smithsonian Institution) exhibited almost alarming celerity in tracking down information and digging up and sending specimens, for which we are most grateful (and spoiled as a result). Thanks are also due to Rich Mooi (California Academy of Sciences) for so helpfully illuminating many of the more obscure byways of cladistics. References Bourseau, J.-P., Cominardi, N. & Roux, M. (1988). La zonation bathymétrique des Crinoïdes pédoncules actuels: un modèle de référence pour les reconstitutions paléobathymétriques. Géologie Méditerranéene, 15 (1), 83–89. Bourseau, J.-P. & Roux, M. (1989). Echinodermes: Crinoïdes Pentacrinidae (MUSORSTOM 2 & CORINDON 2). In J. Forest (Ed.) Résultats des Campagnes MUSORSTOM, Vol. 4. Mémoires du Muséum National d’Histoire Naturelle, Paris (A), 143, 113– 201. Breimer, A. (1978). General morphology Recent crinoids. In R. C. Moore & C. Teichert (Eds) Treatise on Invertebrate Paleontology. Part T, Echinodermata. 2 (1) ( pp. T9 –T58). Boulder, CO and Lawrence, KS: Geological Society of America and University of Kansas. Bremer, K. (1994). Branch support and tree stability. Cladistics, 10, 295–304. Carpenter, P. H. (1881). Preliminary report on the comatulae. Bulletin of the Museum of Comparative Zoology, Harvard, 9 (4 ) 1–20, 1 plate. Clark, A. H. (1907a). New genera of Recent free crinoids. Smithsonian Miscellaneous Collections, 50 (3), 343–364. Clark, A. H. (1907b). Descriptions of new species of Recent unstalked crinoids from the North Pacific Ocean. Proceedings of the United States National Museum, 33, 69 – 84. Clark, A. H. (1908). Descriptions of new species of crinoids, chiefly from the collections made by the U. S. Fisheries Steamer ‘Albatross’ at the Hawaiian Islands in 1902; with remarks on the classification of the Comatulida. Proceedings of the United States National Museum, 34 (1608), 209– 239. Clark, A. H. (1909a). New genera and higher groups of unstalked crinoids. Proceedings of the Biological Society of Washington, 22, 173–178. © The Norwegian Academy of Science and Letters • Zoologica Scripta, 30, 3, July 2001, pp159 – 180 Clark, A. H. (1909b). Descriptions of seventeen new species of Recent crinoids. Proceedings of the United States National Museum, 36 (1691), 633–651. Clark, A. H. (1909c). New Recent Indian crinoids. Proceedings of the Biological Society of Washington, 22, 143–152. Clark, A. H. (1912). Descriptions of twenty new Recent unstalked crinoids belonging to the families Antedonidae and Atelecrinidae from the Dutch East Indies. Notes from the Leyden Museum, 34 (2), 129–155. Clark, A. H. (1915). A monograph of the existing crinoids, 1(1). Bulletin of the United States National Museum, 82, vi + 406, 17 pls. Clark, A. H. (1917). A revision of the crinoid family Antedonidae, with the diagnoses of nine new genera. Journal of the Washington Academy of Science, 7 (5 ), 127–131. Clark, A. H. (1918). The unstalked crinoids of the Siboga Expedition. Siboga Expeditie, 42b, ix + 300, 27 pls. Clark, A. H. (1921). A monograph of the existing crinoids, 1(2). Bulletin of the United States National Museum, 82, xxv + 795, 57 pls. Clark, A. H. (1929). On some Recent crinoids in the collection of the British Museum. Journal of the Linnean Society zZoology), 36, 635–664, pls. 40 – 44. Clark, A. H. (1931). A monograph of the existing crinoids, 1(3). Bulletin of the United States National Museum, 82, vii + 816, 82 pls. Clark, A. H. & Clark, A. M. (1967). A monograph of the existing crinoids, 1(5). Bulletin of the United States National Museum, 82, 1– 860. Clark, A. M. (1970). Echinodermata Crinoidea. Marine Invertebrates of Scandinavia, No. 3. Oslo: Universitetsforlaget. Clark, A. M. (1980). Crinoidea collected by the Meteor and Discovery in the NE Atlantic. Bulletin of the British Museum of Natural History ( Zoology), 38 (4 ), 187–210. Donoghue, M. J., Olmstead, R. G., Smith, J. F. & Palmer, J. D. (1992). Phylogenetic relationships of Dipsacales based on rbcL sequences. Annals of the Missouri Botanical Gardens, 79, 333–345. Gislén, T. (1924). Echinoderm studies. Zoologiska bidrag fran Uppsala, 9, 1–316. Hartlaub, C. (1895). XVIII. Die Comatuliden. Bulletin of the Museum of Comparative Zoology, Harvard, 27 (4 ), 131–152, 4 plates. Kogo, I. (1998). Crinoids from Japan and its adjacent waters. Special Publication of the Osaka Museum of Natural History, 30, 1–148. Levitus, S. & Boyer, T. P. (1994). National Oceanic and Atmospheric Administration Atlas NESDIS 4. World Ocean Atlas 1994, Vol. 4. Temperature (xii + 117 pp.). Washington, DC: US Department of Commerce. Messing, C. G. (1978). Pentametrocrinus atlanticus ( Perrier): (Crinoidea: Echinodermata): a review. Journal of Natural History, 12, 699–708. Messing, C. G. (1985). Submersible observations of deep-water crinoid assemblages in the tropical western Atlantic. In B. F. Keegan & B. D. S. O’Connor (Eds) Proceedings of the Fifth International Echinoderm Conference, Galway (pp. 185–193). Rotterdam: Balkema. Messing, C. G. (1995). Alloeocomatella, a new genus of reef-dwelling feather star from the tropical Indo-West Pacific (Echinodermata: Crinoidea: Comasteridae). Proceedings of the Biological Society of Washington, 108 (3), 436– 450. Messing, C. G. (1997). Living Comatulids. In J. Waters & C. Maples (Eds) Geobiology of Echinoderms, Paleontological Society Papers, 3 (pp. 3–30). Pittsburgh: Carnegie Museum of Natural History. Messing, C. G. (1998). Revision of the Recent Indo-West Pacific comatulid genus Comaster. Part 1. The type species of Comaster and Phanogenia Lovén (Echinodermata: Crinoidea: Comasteridae). Invertebrate Taxonomy, 12, 191– 209. 179 A revision of the Zenometridae • C. G. Messing & C. M. White Messing, C. G. (2000). Just what is Atelecrinus?: unique morphology in a living bathyal feather star (Echinodermata: Crinoidea). In M. Barker (Ed.) Tenth International Echinoderm Conference, Programme & Abstracts (p. 72). New Zealand: University of Otago. Messing, C. G., Ameziane, N. & Eleaume, M. (2000). Comatulid crinoids of the KARUBAR expedition to Indonesia: the families Comasteridae, Asterometridae, Calometridae and Thalassometridae (Echinodermata: Crinoidea). In A. Crosnier & P. Bouchet (Eds) Résultats des Campagnes MUSORSTOM 21. Mémoires de le Museum National d’Histoire Naturelle, Paris, 184, 627 – 702. Messing, C. G. & Dearborn, J. H. (1990). Marine flora and fauna of the northeastern United States. Echinodermata: Crinoidea. National Oceanic and Atmospheric Administration Technical Report NMFS, 91, 1–30. Meyer, D. L., Messing, C. G. & Macurda, D. B. Jr (1978). Zoogeography of tropical western Atlantic Crinoidea (Echinodermata). Bulletin of Marine Science, 28, 412 – 441. 180 Milsom, C. V., Simms, M. J. & Gale, A. S. (1994). Phylogeny and palaeobiology of Marsupites and Uintacrinus. Palaeontology, 37 (3), 595–607. Rankin, D. L. (2000). A taxonomic evaluation of the comatulid genus Stephanometra (Echinodermata). Unpublished M.S. Thesis, Nova Southeastern University, 136pp. Rasmussen, H. W. & Sieverts-Doreck, H. (1978). Articulata classification. In R. C. Moore & C. Teichert (Eds) Treatise on Invertebrate Paleontology, Part T Echinodermata, 2 (3 ) (pp. T813–T928). Boulder, CO and Lawrence, KS: Geological Society of America and University of Kansas. White, C., Messing, C. G., Shivji, M. & Forstner, M. (2000). A phylogenetic reconstruction of the family Comasteridae (Echinodermata: Crinoidea) based on analyses of mitochondrial 16S rRNA sequences. In M. Barker (Ed.) Tenth International Echinoderm Conference, Programme & Abstracts ( p. 99). New Zealand: University of Otago. Zoologica Scripta, 30, 3, July 2001, pp159 – 180 • © The Norwegian Academy of Science and Letters

RELATED PAPERS

RELATED TOPICS

Log In

A revision of the Zenometridae (new rank) (Echinodermata, Crinoidea, Comatulidina)

A revision of the Zenometridae (new rank) (Echinodermata, Crinoidea, Comatulidina)

Related Papers

RELATED PAPERS

RELATED TOPICS