Revista Mexicana de Biodiversidad 79: 91- 102, 2008
A new record and redescription of Schizopera (Schizopera) knabeni (Copepoda:
Harpacticoida: Miraciidae) from north-western Mexico
Un registro nuevo y redescripción completa de Schizopera (Schizopera) knabeni (Copepoda:
Harpacticoida: Miraciidae) del noroeste de México
Samuel Gómez* and Febe Elizabeth Vargas-Arriaga
Instituto de Ciencias del Mar y Limnología-Unidad Académica Mazatlán, Universidad Nacional Autónoma de México. Joel Montes Camarena s/n, 82040
Mazatlán, Sinaloa, México
*Correspondent: samuelgomez@ola.icmyl.unam.mx
Abstract. Specimens of Schizopera Sars, 1905 were found during sampling in 2 brackish systems in central and southern
Sinaloa (north-western Mexico). The specimens turned out to belong to Schizopera (Schizopera) knabeni Lang, 1965 which
was originally described from Monterey Bay (the type locality) and is known from Cocodrie (Louisiana). Amendments to
Lang’s (1965) original description and Fiers and Rutledge’s (1990) partial redescription are given.
Key words: Copepoda, Harpacticoida, Schizopera, north-western Mexico, taxonomy.
Resumen. Durante una serie de muestreos se hallaron ejemplares del género Schizopera Sars, 1905 en 2 sistemas salobres en
el centro y sur de Sinaloa (México). El material recolectado resultó ser Schizopera (Schizopera) knabeni Lang, 1965, una
especie de copépodo harpacticoide originalmente descrita de material recolectado en la Bahía de Monterey (localidad tipo)
y hallada también en Cocodrie (Louisiana, EUA). Se proporcionan enmiendas a la descripción original de Lang (1965) y
a la redescripción parcial de Fiers y Rutledge (1990).
Palabras clave: Copepoda, Harpacticoida, Schizopera, noroeste de México, taxonomía.
Introduction
Since its erection, the genus Schizopera has been the
subject of discussions of its phylogenetic relationships
(Lang, 1948, 1965; Apostolov, 1982; Mielke, 1992).
Lang (1965) was of the opinion that this genus was
monophyletic on the basis of a number of character states
(see below). In 1976 Wells and Rao (1976) suggested
that at least 1 of the species that had been described
(Sch. [Sch.] anomala Coull, 1971) could be regarded as a
minor departure from the Schizopera plan and suggested
that the group composed of Sch. arenicola Chappuis and
Serban, 1953 (=Schizoperopsis (Schizoperopsis) arenicola
(Chappuis and Serban, 1953)), Sch. gauldi Chappuis and
Rouch, 1961 (=Schizoperopsis (Psammoschizoperopsis)
gauldi (Chappuis and Rouch, 1961)) and Sch. varnensis
Apostolov, 1967 (=Sch. (Sch.) varnensis (Apostolov, 1967))
could represent an advanced evolutionary trend within the
genus. Since then, the genus Schizopera has undergone
various changes, the most important being the reallocation
of some species to the genus Eoschizopera Wells and Rao,
Recibido: 03 marzo 2006; aceptado: 12 septiembre 2007
1976 and the subdivision of the genera Schizopera and
Eoschizopera by Apostolov (1982), and the creation of the
genus Schizoperopsis Apostolov, 1982 with 2 subgenera.
Several authors (Mielke, 1992, 1995, Ax, 1987) rejected
Wells and Rao’s (1976) and Apostolov’s (1982) views
because these groups probably represent paraphyla based
on symplesiomorphies. In contrast, Boxshall and Halsey
(2004) adopted Wells and Rao’s (1967) and Apostolov’s
(1982) schemes.
Lang (1965) did not describe or illustrate most of
the mouth parts of Sch. (Sch.) knabeni from Monterey
Bay. Later, Fiers and Rutledge (1990) presented some
amendments to Lang’s (1965) original description based on
material collected in Louisiana, but they did not describe
all the mouth parts. The present paper offers a complete
redescription based on material collected in 2 brackish
systems in northwestern Mexico.
Material and methods
Sediment samples for meiofaunal analyses were taken
during a number of sampling campaigns in 2 brackish
92
Gómez and Vargas-Arriaga.- New record of Schizopera (Schizopera) knabeni from Mexico
systems in central and southern Sinaloa state (Ensenada
del Pabellón lagoon and El Verde estuary) during the early
1990s (see Gómez Noguera and Hendrickx, 1997) and
during 2005. Sediment samples were sieved through 500
μm and 40 μm sieves and benthic copepods were separated
from the rest of the meiofauna with a stereomicroscope
at 40X magnification. Specimens were stored in 70%
ethanol. Observations and drawings at a magnification of
1000X were made from whole and dissected specimens
mounted in lactophenol with a Leica compound microscope
equipped with phase contrast and a drawing tube. The type
material was deposited in the Copepoda collection of the
Instituto de Ciencias del Mar y Limnología, Mazatlán
Marine Station. The terminology proposed by Huys and
Boxshall (1991) for the general description was adopted.
Abbreviations used in the text and tables are: CIII, third
copepodite; CIV, fourth copepodite; CV, fifth copepodite;
P1-P6, first to sixth swimming legs; Exp, exopod; Enp,
endopod; P1 (P2-P4) Exp (Enp) 1 (2, 3) denotes the
proximal (middle, distal) exopodal (endopodal) segment
of P1, P2, P3 or P4.
Redescription
Order: Harpacticoida Sars
Family: Miraciidae Dana, 1846
Subfamily: Diosaccinae Sars, 1906
Genus: Schizopera Sars, 1905
Subgenus: Schizopera Sars, 1905
Schizopera (Schizopera) knabeni Lang, 1965 (Figs. 1-8)
Female. Body fusiform, tapering posteriorly (Fig. 1A). Total
length ranging from 520 to 534 μm from tip of rostrum to
posterior margin of caudal rami. Rostrum (Fig. 3A) distinct,
somewhat elongated, triangular, with 1 setule on each side
laterally. Cephalothorax with surface sensilla and plain
hyaline frill. Dorsal and ventral surface of prosomites and
first urosomite, genital double-somite and fourth urosomite
with spinular pattern as figured (Figs. 1A, B; 2A). P2-P4bearing somites with plain caudal frill; P5-bearing somite,
genital double-somite, and fourth urosomite with finely
serrated frill. Genital double-somite fused dorsally (Fig. 1A)
and ventrally (Fig. 2A), with lateral trace of division between
second and third urosomites (Fig. 1B); ventral surface plain
except for transverse rows of minute spinules close to P6,
the latter represented by 1 outer, short, plumose seta and 1
inner, long, slender element (Fig. 2A). Fifth urosomite with
dorsal and ventral spinular pattern as figured (Fig. 1A, B;
2A), with finely serrated frill; dorsally with posterior frill
bulging medially. Anal somite ornamented as figured (Fig.
1A, B; 2A); anal operculum with fringing spinules, and with
long ventrolateral spinules close to articulation with caudal
rami, the latter tapering posteriorly, about 1.3 times as long
as wide, with 6 elements as shown (Fig. 2B, C, D).
Antennule (Fig. 3A) 8-segmented; surface of segments
smooth; second segment about 1.5 times as long as wide.
Armature formula as follows: 1-(1), 2-(9), 3-(5), 4-(3+ae),
5-(2), 6-(2), 7-(5), 8-(5+acrothek). Acrothek consists of 2
setae basally fused to an aesthetasc.
Antenna (Fig. 3B) with allobasis armed with 1 abexopodal
seta and ornamented with short rows of spinules along
inner and outer margin proximally and at base of exopod.
Exopod two-segmented; first segment with 1 seta, second
segment with 2 setae and ornamented with spinules distally.
Endopodal segment with longitudinal row of long spinules
along inner margin, with 2 strong spines and 1 slender seta
laterally and 7 distal elements (2 outermost elements fused
basally).
Mandible (Fig. 4A). Gnathobasis with dentate pars
incisiva, some spinules, and 1 seta. Coxa-basis with
spinules as figured and 3 plumose setae distally. Endopod
1-segmented, with 2 setae laterally and 5 elements distally.
Exopod consisting of a small segment with 2 setae, 1 of them
small.
Maxillule (Fig. 4B). Praecoxal arthrite with 6 strong
spines and 1 seta distally, 2 pinnate lateral elements, and
2 surface setae. Coxa with 2 setae. Basis with 7 elements.
Endopod 1-segmented with 3 setae. Exopod minute, fused to
basis, with 2 setae.
Maxilla (Fig. 4C). Syncoxa with 3 endites; proximal
endite minute with 2 setae; middle and distal endites well
developed, with 2 and 3 setae respectively. Basis with 1 claw,
1 strong and 2 slender elements. Endopod 2-segmented; first
segment with 2, second segment with 4 setae.
Maxilliped (Fig. 4D). Basis with spinules and armed
with 1 subdistal and 2 apical pinnate setae. First endopodal
segment with spinules along inner margin and with 2 setae;
second segment with strong claw and 2 accompanying setae
(1 of them very small).
P1 (Fig. 5A). Coxa with transverse spinular rows as
figured. Basis with spinules at base of inner and outer spines
and between rami. Exopod 3-segmented, smaller than first
endopodal segment; third exopodal segment with 4 elements.
Endopod 3-segmented; first segment about 6 times as long
as wide, longer than second and third segments combined,
with 1 strong element subdistally; second segment without
armature; third segment with 1 inner slender, small seta, 1
geniculate seta, and 1 spine.
P2 (Fig. 5B). Coxa furnished with short spinular rows as
figured. Basis with spinules at base of outer spine and at base
of endopod. Rami 3-segmented. Exopod slightly shorter than
endopod; Exp1 and 3 without, Exp2 with inner seta; Exp3
with 4 elements. First endopodal segment without, second
Revista Mexicana de Biodiversidad 79: 91- 102, 2008
Figure 1. Schizopera (Schizopera) knabeni Lang, female. A,
habitus, dorsal; B, habitus, lateral, showing only a portion of the
egg sac. Scale bar: 200 μm.
93
Figure 2. Schizopera (Schizopera) knabeni Lang, female. A,
urosome, ventral (P5 bearing-somite omitted); B, caudal ramus,
ventral; C, caudal ramus, dorsal; D, caudal ramus, lateral. Scale
bar: A, 160 μm; B-D, 109 μm.
94
Gómez and Vargas-Arriaga.- New record of Schizopera (Schizopera) knabeni from Mexico
Figure 3. Schizopera (Schizopera) knabeni Lang, female. A, rostrum and antennule; B, antenna. Scale bar: A, 100 μm; B, 70 μm.
Revista Mexicana de Biodiversidad 79: 91- 102, 2008
95
Figure 4. Schizopera (Schizopera) knabeni Lang, female. A, mandible; B, maxillule; C, maxilla; D, maxilliped; E, P5. Scale bar: A-D,
70 μm; E, 100 μm.
96
Gómez and Vargas-Arriaga.- New record of Schizopera (Schizopera) knabeni from Mexico
Figure 5. Schizopera (Schizopera) knabeni Lang, female. A, P1; B, P2. Scale bar: 100 μm.
Revista Mexicana de Biodiversidad 79: 91- 102, 2008
and third segments with 1 inner seta (inner seta of Enp3 very
strong); Enp3 with 4 setae in all.
P3 (Fig. 6A). Coxa with short spinular rows as figured.
Basis with spinules at base of outer spine and at base of
endopod. Rami 3-segmented. Exopod slightly longer than
endopod; Exp1 and 3 without, Exp2 with inner seta; Exp3
with 4 elements. Endopodal segment with 1 inner seta (inner
seta of Enp3 very strong); Enp3 with 4 setae in all.
P4 (Fig. 6B). Coxa and basis as in P3. Exopod as in P3;
visibly longer than endopod. Endopod as in P3 except for
lack of inner seta on P4Enp3.
Armature formula as follows:
P1
P2
P3
P4
Exp
Enp
I-0;I-0;II,2,0
I-0;I-1;II,2,0
I-0;I-1;II,2,0
I-0;I-1;II,2,0
0-1;0-0;I11
0-0;0-1;I,2,12
0-1;0-1;I,2,1
0-1;0-1;I,20
P5 (Fig. 4E). Rami distinct. Baseoendopodal lobe
with 2 inner and 2 distal setae. Exopod reaching beyond
baseoendopod, with 6 setae.
Male. Habitus (not shown) as in female, except for genital
double-somite (see Fig. 7A). Total body length ranging from
518 to 528 μm from tip of rostrum to posterior margin of
caudal rami. Anal somite and caudal rami as in female (Fig.
7A).
Antennule (Fig. 7B) haplocer; 8-segmented; third
segment narrow; fourth segment swollen; with aesthetasc on
fourth and seventh segments.
Mouth parts (not illustrated) as in female.
P1 as in female, except for dimorphic inner process of
basis (Fig. 8A).
Coxa, basis, and exopod of P2 (not shown) as in female.
Endopod 2-segmented (Fig. 8B); proximal segment with
slender spinules on inner and outer margin; distal segment
with outer apophysis, with 4 elements in all.
Coxa, basis, and endopod of P3 (not shown) as in female.
Exopod 3-segmented; first and second segment as in female;
third segment with hyaline subdistal spine (Fig. 8C).
P4 (not illustrated) as in female.
Both P5 fused medially. Baseoendopodal lobe
with 2 strong, pinnate spines. Exopod reaching beyond
baseoendopodal lobe, with 5 elements as figured.
P6 (Fig. 7A) represented by asymmetrical smooth plates,
without armature.
Variability. One female had a 7-segmented antennule, third
and fourth segments being partially fused.
97
Taxonomic summary
Material examined. Five dissected females (EMUCOP080405-03, EMUCOP-030192-70, EMUCOP-03019271, EMUCOP-300392-59, EMUCOP-300392-60) and
6 dissected males (EMUCOP-090205-05, EMUCOP010591-61, EMUCOP-230691-49, EMUCOP-30039257, EMUCOP-300392-58, EMUCOP-300491-51), 1
(EMUCOP-090205-06), 10 (EMUCOP-300392-63) and 18
females (EMUCOP-300392-72), and 12 (EMUCOP-30039276), 1 (EMUCOP-080405-04), and 19 males (EMUCOP300392-64) preserved in alcohol. Collected: 30 April, 1 May,
and 23 June 1991; 3 January and 30 March 1992 (Ensenada
del Pabellón lagoon (stn. 2, 6, 7, 9, 12 [for more information
regarding environmental variables see Gómez Noguera and
Hendrickx (1997)]), coll. S. Gómez; 8 April and 9 February
2005 (El Verde Estuary (stn. 7 and 2, Gómez, unpubl data),
dissolved oxygen content from 2.6 to 4.9 ml l-1, biochemical
oxygen demand from 0.3 to 2.2 ml l-1, sand, clay, and silt
content in the sediment from 5.7% to 26.1%, from 24.2%
to 51.2%, and from 32.8% to 80.5% respectively, salinity
from 20‰ to 21 ‰, bottom-water temperature from 21.5 ºC
to 24.8 ºC, sediment deposition from 0.0007 kg m-2 day-1 to
0.9 kg m-2 day-1, coll. F. E. Vargas-Arriaga, F. N. MoralesSerna, and S. Gómez.
Additional material available. 39 females, 23 males, 4 CI,
15 CII, 13 CIII, 12 CIV, 15 CV collected on 30 April and
23 June 1991 and 3 January and 30 March 1992 (Ensenada
del Pabellón lagoon (stn. 2, 4, 6, 7, 9, 10, 12 [for more
information regarding environmental variables see Gómez
Noguera and Hendrickx 1997]), 9 February and 8 April
2005 (El Verde Estuary (stn. 1, 2, 6, 7, Gómez, unpubl data),
dissolved oxygen content from 2.4 to 3.7 ml l-1, BOD from
0.5 to 0.8 ml l-1, sand, clay, and silt content of the sediment
from 3.4% to 9.4%, from 45.3% to 64.4%, and from 32.2%
to 45.3% respectively, salinity from 20‰ to 21 ‰, bottomwater temperature from 20.8 ºC to 25 ºC, sediment deposition
from 0.0003 kg m-2 day-1 to 0.001 kg m-2 day-1
Distribution. Monterey Bay, Elkhorn Slough (type locality)
(Lang, 1965), Cocodrie (Louisiana) (Fiers and Rutledge,
1990); Mexico: Ensenada del Pabellón lagoon (24°19’24°35’N, 107°28’-107°45’W) and El Verde estuary
(23º25’30”N 106º33’30”W) (Sinaloa State) (present study).
Remarks
Since its creation to accomodate Sch. longicauda Sars,
1905 (=Sch. (Sch.) longicauda Sars, 1905), the genus
Schizopera has been the subject of discussions regarding its
phylogenetic relationships (Lang, 1948, 1965; Apostolov,
1982; Mielke, 1992). In Lang’s (1948) monograph, 38
98
Gómez and Vargas-Arriaga.- New record of Schizopera (Schizopera) knabeni from Mexico
Figure 6. Schizopera (Schizopera) knabeni Lang, female. A, P3; B, P4. Scale bar: 100 μm.
Revista Mexicana de Biodiversidad 79: 91- 102, 2008
Figure 7. Schizopera (Schizopera) knabeni Lang, male. A,
urosome, ventral (P5 bearing-somite omitted); B, antennule.
Scale bar: A, 71 μm; B, 50 μm.
99
Figure 8. Schizopera (Schizopera) knabeni Lang, male. A, basis
of P1; B, P2Enp; C, P3Exp3; D, P5. Scale bar: 50 μm.
100
Gómez and Vargas-Arriaga.- New record of Schizopera (Schizopera) knabeni from Mexico
species were included in the genus Schizopera. In Lang
(1965), after reallocation of the species at that time
described, the number of species belonging to Schizopera
increased to 42 (Lang, 1965, :324-326). Lang (1965) was
of the opinion that this genus was monophyletic on the
basis of a), the presence of a modified hyaline spine on the
inner edge of the third exopodal segment of the male P3
(the “universal” presence of this hyaline spine within the
genus and related genera was later confirmed by Wells and
Rao (1976), even for the species for which this information
was not available); b), the uniform transformation of the
inner spine of the basis of the first leg in the males; c),
the conformity of the female genital area; d), the loss
of the proximal outer spine on the terminal exopodal
segment of P1-P4, and e), the antenna with allobasis
and 2-segmented exopod. By 1976, 5 species had been
reported that departed from the Schizopera antennal plan.
Wells and Rao (1976) were of the opinion that 1 of those
species, Sch. (Sch.) anomala, could be regarded as a minor
departure from the Schizopera plan, because it had an
allobasis but a 1-segmented exopod. They suggested that
the group of species composed of Sch. (Sch.) arenicola,
Sch. (Ps.) gauldi and Sch. (Sch.) varnensis, which have a
2-segmented P4Enp, and the species with a 2-segmented
P1Enp could represent an “advanced evolutionary trend”
within the genus. On the other hand, following Wells
and Rao (1976), the more primitive antenna (with basis
and a 2- or 3-segmented exopod), and setation of P2-P4
of some other species could not be explained with such a
simple model and erected Eoschizopera Wells and Rao,
1976 to include Sch. crassispinata Chappuis, 1954 (=E.
(Praeoschizopera) crassispinata (Chappuis, 1954)), Sch.
gligici Petkovski, 1957 (=E. (P.) gligici (Petkovski, 1957)),
Sch. indica Rao and Ganapati, 1969 (=E. (P.) indica (Rao
and Ganapati, 1969)), Sch. syltensis Mielke, 1973 (=E.
(E.) syltensis (Mielke, 1973)), E. (E.) reducta Wells and
Rao, 1976 and Sch. marlieri Rouch and Chappuis, 1960
(=E. (P.) marlieri (Rouch and Chappuis, 1960)), the
latter considered as incertae sedis because the state of its
antenna was in doubt. At that time, several genera had
been erected and were supposed to be related to some
extent to the Schizopera-group (Psammotopa Pennak,
1942, Actopsyllus Wells, 1967, Protopsammotopa Geddes,
1968, Balucopsylla Rao, 1972, Helmutkunzia Wells and
Rao, 1976, Paraschizopera Wells, 1981, and questionably
Goffinella Wilson, 1932 and Schizoperoides Por, 1968).
In an attempt to clarify the identity of the species
belonging to the groups related to Schizopera, Apostolov
(1982) created 2 subgenera of the genus Schizopera
(characterized primarily by an antenna with allobasis
and a 2-segmented antennal exopod): Schizopera
(Schizopera) and Schizopera (Neoschizopera) Apostolov,
1982 on the basis of the structure of the P1Enp (3- and
2-segmented in Sch. (Sch.) and Sch. (N.) respectively).
Additionally, Apostolov (1982) divided the species of
the genus Eoschizopera into 2 subgenera: Eoschizopera
(Eoschizopera) Wells and Rao, 1976 (E. (E.) syltensis)
and Praeoschizopera Apostolov, 1982 (E. (P.) indica,
E. (P.) crassispinata, E. (P.) marlieri and E. (P.) gligici),
mainly based on the structure of P1Enp (3-segmented in
E. (E.) and 2-segmented in E. (P.)), antennal exopod (3and 2-segmented in E. (E.) and E. (P.) respectively), and
chaetotaxy of the female P5Exp (with 5 and 6 setae in E.
(E.) and E. (P.) respectively). Apostolov (1982) also erected
the genus Schizoperopsis Apostolov, 1982 (characterized
primarily by a 2-segmented P4Enp), with 2 subgenera:
Schizoperopsis (Schizoperopsis) Apostolov, 1982 and
Schizoperopsis (Psammoschizoperopsis) Apostolov, 1982
on the basis of the presence of a 2-segmented endopod of
P1 and P4.
According to Mielke (1992, 1995) and Ax (1987), the
erection of the genera Eoschizopera and Schizoperopsis,
and of all the subgenera created by Apostolov (1982),
should be refused on the basis that they probably represent
paraphyla based on symplesiomorphies, while Mielke’s
group B (1992: 90) (Eoschizopera, Schizopera, and
Schizoperopsis) should be interpreted as a monophylum
because the hyaline spine on the male P3Exp3 is restricted
to this group and can be equated with the genus Schizopera.
However, the division by Apostolov (1982) is at least
of diagnostic value, and some authors (Boxshall and
Halsey, 2004) have adopted Wells and Rao’s (1967) and
Apostolov’s (1982) schemes.
The Mexican material resembles the original description
of Sch. (Sch.) knabeni in the shape and relative length of
the segments of the antennule, armature complement of the
endopod and exopod of the antenna, armature formula and
relative length of the rami and setae of P1-P5, and shape of
the caudal frill of urosomites (minutely serrate). In fact, the
only differences observed between the Mexican specimens
and Lang’s (1965) description were a), the setation of
the maxillulary exopod (with 1 small seta only in Lang’s
(1965: 331) description, with 2 long setae in the Mexican
specimens), and b), the relative length of the dimorphic
hyaline spine of the male P3 third exopodal segment
(not reaching the tip of the supporting segment in Lang’s
(1965) description, reaching the tip of the third exopodal
segment in the Mexican material). Unfortunately, Lang
(1965) omitted the illustrations and written description
of the other mouth parts because they agreed “almost
exactly with those” of Sch. (Sch.) californica Lang, 1965.
If this is the case, then a), the armature complement of the
mandibular exopod (with 1 small seta in Lang’s (1965)
illustration, with 2 setae in the Mexican material); b),
Revista Mexicana de Biodiversidad 79: 91- 102, 2008
the relative length of the lateral setae on the mandibular
endopod (1 of them small in Lang’s (1965) illustration,
but of about the same length in the Mexican material);
c), the apical armature complement of the mandibular
endopod (with 4 setae in Lang’s (1965) illustration,
with 5 setae in the Mexican specimens; this can be a
misinterpretation though); d), the armature complement of
the maxillulary basis (with 5 setae only in Lang’s (1965)
illustration, with 7 setae in the Mexican specimens); e),
the armature complement of the maxillulary endopod
(with 2 short setae in Lang’s (1965) illustration, with 3
setae (1 of them smaller) in the Mexican specimens); f),
armature complement of maxillary endopod (1-segmented
and armed with 4 setae in Lang’s (1965) illustration, 2segmented and armed with 6 setae in all in the Mexican
specimens), and g), armature complement of the basis and
second endopodal segment of the maxilliped (basis with 2
setae and second endopodal segment with 1 accompanying
seta in Lang’s (1965) illustration, basis with 3 setae and
second endopodal segment with 2 accompanying setae in
the Mexican material) are also different. Of course, this
required careful inspection of Lang’s (1965) material. One
of us (SG) had the opportunity to examine Lang’s material
of Sch. (Sch.) knabeni. The material was deposited in the
collection of the Swedish Museum of Natural History
under the catalogue number SMNH-Type-2203 syntype(s).
In the label appears the following: Schizopera knabeni
Lang, 1965; USA, Monterey Bay, Elkhorn Slough; Mud,
amongst cast away Enteromorpha; Leg. K. Lang 17
Sep 1960. In the vial there was only 1 male somewhat
damaged and with the prosome and urosome separated.
Since this was the only specimen in the vial we refrained
from dissecting it and the observations were made from
the whole specimen. Regarding the differences above, we
confirmed the presence of 2 long setae on the maxillulary
exopod in Lang’s material, as in the Mexican specimens.
Also, the relative length of the dimorphic hyaline spine in
Lang’s material is the same as in the Mexican specimens.
Regarding the mouth parts whose descriptions were
omitted by Lang (1965) (see above), it was confirmed
that the armature complement of the mandibular exopod,
the relative length of the lateral setae on the mandibular
endopod, the apical armature complement of the
mandibular endopod, as well as the armature complements
of the maxillulary basis and endopod, of the maxillary
endopod and of the basis and second endopodal segment of
the maxilliped of the Mexican and Lang’s material are the
same. Also, Lang’s material has short transversal spinular
rows on free prosomites and urosomites and the spinular
pattern is similar to that of the Mexican specimens and to
that showed by Fiers and Rutledge (1990).
Fiers and Rutledge (1990) gave a partial redescription/
101
amendment of the species based on specimens collected
in Cocodrie (Louisiana). These amendments (except for
the presence of seta I in the caudal rami of Fiers and
Rutledge’s (1990: 107, Fig. 1b, f)) agree well with the
description by Lang (1965) and the description herein
presented for the Mexican material. Fiers and Rutledge
(1990) mentioned the following differences between their
material from Louisiana and Lang’s (1965) description:
a), the dorsal spinular ornamentation of the prosomites
and urosomites: upon careful inspection of Lang’s type
material, the presence of short transverse spinular rows
on free prosomites and urosomites was verified; b), the
spinular ornamentation of the ventral surface of second
and third abdominal somites: such spinular ornamentation
is also present in Lang’s type material; c), the presence
of hyaline frills in the cephalothorax, prosomites and
urosomites (except for the anal somite): on this regard, the
hyaline frill of cephalothorax of Lang’s type material is
definitely plain, while the hyaline frill of free prosomites
and urosomites is finely serrated. Dr. Guilherme Lotufo
(U. S. Army Engineer Research and Development Center)
kindly sent to us some cultured specimens of Sch. (Sch.)
knabeni. The original stock of this material comes from
Cocodrie (Louisiana), the same locality where Fiers and
Rutledge (1990) found the specimens upon which they
based their redescription. Upon careful examination of the
specimens sent to us by Dr. Lotufo, we concluded that the
cephalothorax of the specimens from Louisiana possesses
a plain hyaline frill as in Lang’s type material and as in the
Mexican specimens; d), the shape of the inner spines of
the female P5 baseoendopod: unfortunately there is only 1
male in the vial containing Lang’s type material. However,
the shape of the spines of the female P5 baseoendopod
observed for the material from Louisiana and Mexico is
the same, thus being probable that the more slender shape
of these elements in Lang’s (1965) description is simply
a slip of the pen; e), the presence of an aesthetasc on the
last male and female antennular segment: in this regard
Fiers and Rutledge (1990) noted that Lang (1965) omitted
this aesthetasc in both Sch. (Sch.) knabeni and Sch. (Sch.)
californica Lang, 1965, and suggested that the presence of
such aesthetasc could be a common feature for the genus.
Unfortunately, Lang’s type material of the species is badly
damaged and the presence of such aesthetasc could not be
verified; f), the shape of the dimorphic inner spinule and
the inner projection of the basis of the male P1: both the
dimorphic spinule and the inner projection of the basis of
the male P1 of Lang’s type material are identical to those
observed by Fiers and Rutledge (1990) in specimens from
Louisiana and to those observed in the Mexican specimens,
and g), presence of the male P6: the male P6 showed by
Fiers and Rutledge’s (1990) is identical to that observed in
102
Gómez and Vargas-Arriaga.- New record of Schizopera (Schizopera) knabeni from Mexico
Lang’s type material and in the Mexican specimens.
More evident are the following differences between
Lang’s (1965) description and the Mexican specimens,
and Fiers and Rutledge’s (1990) material: a), the different
shape of the frill of the fifth urosomite (overlapping the
anal segment almost entirely in Fiers and Rutledge’s
(1990) illustration, barely overlapping the proximal half
of the anal segment in Lang’s (1965) illustration and in
the Mexican specimens), and b), the armature complement
of the caudal rami (with 7 setae in Fiers and Rutledge’s
(1990) specimens (seta I present), with 6 setae only in
Lang’s (1965) and in the Mexican material (seta I absent).
The condition of the frill of the fifth urosomite as shown
in Fiers and Rutledge (1990) is the result of the intrusion
of the anal somite into the fifth urosomite, therefore being
identical to that of Sch. (Sch.) knabeni as described by
Lang (1965) and in the present paper. On the other hand,
and after careful inspection of the material sent to us by
Dr. Lotufo, it is clear that the seta I of the caudal rami as
shown in Fiers and Rutledge’s (1990: 107, Fig. 1b, f) is
in fact 1 of several spinules normally present at the base
of seta II. All the evidence above supports the presence
of Sch. (Sch.) knabeni in California, south-eastern Gulf
of California (Mexico) and Louisiana (Gulf of Mexico,
U.S.A.).
Acknowledgements
The authors are grateful to Sergio Rendón Rodríguez
and Neptalí Morales-Serna for their help during field work
and sample processing. The authors are also grateful to D.
John Fleeger (Louisiana State University) for his kind help
in attempting to obtain specimens of Sch. (Sch.) knabeni
from Louisiana. We are deeply indebted to Dr. Guilherme
Lotufo (U. S. Army Engineer Research and Development
Center) for providing us with specimens of Sch. (Sch.)
knabeni from Louisiana. This paper is a contribution
to project IN217606-2 financed by the Research and
Technological Innovation Projects Support Programme
(Programa de Apoyo a Proyectos de Investigación e
Innovación Tecnológica) of the Office for General Affairs
of the Academic Staff (Dirección General de Asuntos
del Personal Académico) of the National Autonomous
University of Mexico (UNAM).
Literature cited
Ax, P. 1987. The phylogenetic system. The systematization of
organisms on the basis of their phylogenesis. John Wiley,
Chichester. 340 p.
Apostolov, A. 1982. Genres et sous-genres nouveaux de la famille
Diosaccidae Sars et Cylindropsyllidae Sars, Lang (Copepoda,
Harpacticoidea). Acta Zoologica Bulgarica 19:37-42.
Boxshall, G. A. and S. H. Halsey. 2004. An introduction to copepod
diversity, 1-2. The Ray Society, London. 966 p.
Fiers, F. and Ph. Rutledge. 1990. Harpacticoid copepods
associated with Spartina alterniflora culms from the marshes
of Cocodrie, Louisiana (Crustacea, Copepoda). Bulletin
del’Institut Royal des Sciences Naturelles de Belgique
60:105-125.
Gómez Noguera, S. E. and M. Hendrickx. 1997. Distribution and
abundance of meiofauna in a subtropical coastal lagoon in the
South-eastern Gulf of California, Mexico. Marine Pollution
Bulletin 34:582-587.
Huys, R. and G. A. Boxshall. 1991. Copepod evolution. The Ray
Society, London. 468 pp.
Lang, K. 1948. Monographie der Harpacticiden. Håkan Ohlsson,
Lund, Sweden, Vols. 1,2. 1682 p.
Lang, K. 1965. Copepoda Harpacticoidea from the Californian
Pacific coast. Kungliga Svenska Vetenskapsakademiens
Handlingar Fjárde Serien, 10:1-560.
Mielke, W. 1992. Description of some benthic Copepoda from
Chile and a discussion on the relationships of Paraschizopera
and Schizopera (Diosaccidae). Microfauna Marina 7:79100.
Mielke, W. 1995. Species of the taxon Schizopera (Copepoda)
from the Pacific coast of Costa Rica. Microfauna Marina
10:89-116.
Wells, J. B. J. and G. C. Rao. 1976. The relationship of the genus
Schizopera Sars within the family Diosaccidae (Copepoda:
Harpacticoida). Zoological Journal of the Linnean Society
58:79-90.