Caprella Kuroshio, A New Species (Crustacea : Amphipoda : Caprellidae), With A Redescription Of Caprella Cicur Mayer, 1903, And An Evaluation Of The Genus Metacaprella Mayer, 1903

17 Pages·1999·7.1 MB·

by  A Mori

PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
112(4):722-738. 1999.
Caprella kuroshio, a new species (Crustacea: Amphipoda:
Caprellidae), with a redescription of Caprella cicur Mayer, 1903, and
an evaluation of the genus Metacaprella Mayer, 1903
Atsushi Mori
Seto Marine Biological Laboratory, Kyoto University, Shirahama, Wakayama 649-2211, Japan
—
Abstract. A new species of Caprella, C. kuroshio, is described based on
the specimens collected from the Pacific coast of central Japan. Caprella cicur
Mayer, 1903, closely related to the new species, is redescribed based on the
type material. The new species differs from C. cicur in the shape of the per-
eonites and the second gnathopod. The female of the new species has a pair
of abdominal appendages, which is a diagnostic character of the genus Meta-
caprella Mayer, 1903. However, the abdominal appendage is considered to be
a polymorphic and symplesiomorphic character in Caprella and Metacaprella.
Therefore, the genus Metacaprella is not recognised, and the new species is
assigned to the genus Caprella.
In 1991, during a study of the caprellid Prefecture, Japan. Paratypes (SMBL Type
fauna of the west coast of Shikoku, western No. 392): 10 males, 10 females, collected
Japan, numerous specimens of a caprellid together with holotype.
—
species were collected by the author from Additional material examined. 10
the red algae, Gelidium elegans Kiitzing, at males, 10 females, 4 Jun 1992, on Gelidium
m
Kashiwajima Island, Kochi Prefecture. Af- elegans, 1 in depth, Sabiura, Kushimoto
terward, many individuals of the same spe- (33°28'N, 135°46'E), Wakayama Prefec-
cies also were found on G. elegans in Ku- ture, Japan; 1 male, 10 Apr 1993, on drift-
shimoto and Shirahama, Wakayama Prefec- ing Sargassum sp., off the mouth of Fuji
ture, in 1992 and 1996 respectively. Fur- River, Suruga Bay (35°04'N, 138°39'E),
thermore, a single specimen of the species Shizuoka Prefecture, Japan; 5 males, 5 fe-
was collected from the drifting brown al- males, 16 Jun 1996, on Gelidium elegans,
gae, Sargassum sp., in Suruga Bay in 1993. depth unrecorded, Rinkai, Shirahama
Detailed examination revealed that all of (33°42'N, 135°21'E), Wakayama Prefec-
these specimens belong to a new species.
ture, Japan.
—
The description of the species is presented Description of holotype. Body (Fig.
here. mm
lA) 9.65 long, smooth. Head with
The type series is deposited in the Seto
blunt triangular projection directed straight
Marine Biological Laboratory, Kyoto Uni-
forward; pereonite 1 shorter than head; per-
versity (SMBL).
eonite 2 longer than pereonite 3, with single
acute projection on ventral surface between
Caprella kuroshio, new species
insertions of second gnathopods (Fig. IB).
Figs. 1-5
Antenna 1 (Fig. lA) longer than a half
—
Type material. Holotype (SMBL Type of the body length; flagellum consisting of
No. 391): male, 26 Apr 1991, on Gelidium 14 segments, shorter than peduncle. Anten-
m
elegans, 2 in depth, Sankaku-bae, Kash- na 2 (Fig. lA) shorter than peduncle of an-
iwajima Island (32°46'N, 132°38'E), Kochi tenna 1; peduncular segments 3-5 with 2
VOLUME 112, NUMBER 4 723
®
B
Fig. 1. Caprella kuroshio, new species, holotypic male: A, body, lateral view; B, pereonite 2, lateral view;
C, abdomen. Scales: A, B = 1.0 mm; C = 0.1 mm.
724 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
rows of dense long setae on ventral surfac- tylus falcate, bearing rows of numerous
es; flagellar segment 1 with 2 rows of dense teeth on grasping margin.
long setae on ventral surface. Gnathopod 2 (Figs. lA, 3C) attached to
Upper lip (Fig. 2A) semicircular, slightly midpoint of pereonite 2. Basis shorter than
concave on apical margin, densely pubes- pereonite 2 in length, bearing laterodistal
cent. Inner and outer lobes of lower lip and mediodistal triangular projections. Is-
(Fig. 2B) well-developed, round, densely chium bearing lateral triangular projection.
pubescent on apicomedial margins; man- Propodus oblong, two times longer than ba-
dibular process developed. sis. Palmar comer produced, bearing single
Mandible (Fig. 2C-D) without palp. Left large grasping spine on apex. Palmar mar-
and right sides consisting of 5- and 4- gin slightly concave, bearing a pair of small
toothed incisor, 5- and 6-toothed lacinia grasping spines on proximal end, subdistal
mobilis, and setal row of 3 and 2 plumose poison tooth, and distal triangular projec-
setae respectively. Molar process well-de- tion. Dactylus curved and narrowed distal-
veloped, with 1 plumose seta; left molar ly-
with triangular stout projection; right molar Gills (Fig. lA) present on pereonites 3-
with pubescent molar extension. 4, large, oval.
Maxilla 1 (Fig. 2E) without inner lobe. Pereopods 5-7 (Figs. 4A-C) morpholog-
Its outer lobe rectangular, with 3 simple and ically similar, but increasing in size poste-
4 serrate spines on apical margin. Palp 2- riorly. Basis bearing triangular dorsal pro-
segmented. Its distal segment bearing a row jection at posterior end. Merus inflated dor-
of teeth and 6 spines on apical margin, 7 sally. Propodus longest; palm bearing a pair
setae on inner margin, 2 rows of setae on of grasping spines on proximal comer, and
ventral surface. rows of short setae on slightly concave
Inner lobe of maxilla 2 (Fig. 2F) shorter grasping margin. Dactylus bearing minute
than outer lobe, oval, with 2 rows of nu- serration on curved grasping margin.
merous setae on apicomedial margin. The Abdomen (Fig. IC) consisting of a pair
outer lobe rectangular, with 2 rows of setae of appendages, a pair of lateral lobes, and
on apical margin. single dorsal lobe. Abdominal appendage 2-
Inner lobe of maxilliped (Fig. 3A) small, segmented; three setae present on both
with 3 short spines on apical margin, and proximal and distal segments; tip of distal
numerous marginal setae. Outer lobe small, segment round. Lateral lobes bearing 6—7
subequal to palpal segment 1 in length, proximal and 4-5 distal setae. Penes large,
bearing 1 long stout seta on apex, 7 short situated medially. —
spines on medial margin, and numerous Description ofparatypic female. Body
mm
marginal setae. Palp 4-segmented; segment (Fig. 5A-B) 6.90 long. Pereonite 2
1 short; segments 1—2 bearing numerous subequal to pereonite 3 in length.
long setae on medial margins, and segment Antenna 1 (Fig. 5A) subequal to a half
3 on apicomedial surface; segment 4 fal- of the body length. Flagellum consisting of
cate, longer than apical setae on segment 3, 13 segments, subequal to peduncle in
with rows of setulae on grasping margin. length. Antenna 2 (Fig. 5A) longer than pe-
Gnathopod 1 (Fig. 3B) robust. Its ischi- duncle of antenna 1.
um and merus short, with setae on ventral Gnathopod 2 (Figs. 5A, C) attached to
surfaces. Carpus expanded ventrally, bear- anterior end of pereonite 2. Propodus oval.
ing numerous setae. Propodus bearing rows Palmar margin slightly convex, bearing
of setae on medial surface. Palm bearing a subdistal small poison tooth and distal tri-
pair of grasping spines at the proximal cor- angular projection. Dactylus slightly
ner, its grasping margin straight and mi- curved.
nutely serrate, bearing rows of setae. Dac- Abdomen (Fig. 5D) consisting of a pair
VOLUME 112, NUMBER 4 725
Fig. 2. Caprella kuroshio, new species, holotypic male: A, upper lip; B; lower lip; C, left mandible; D, right
mandible; E, maxilla 1; F, maxilla 2. Scales; 0.1 mm.
726 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
Fig. 3. Caprella kuroshio, new species, holotypic male: A, maxilliped; B, gnathopod 1; C, gnathopod 2 with
details of palmar projections indicated by arrows. Scales: A, B = 0.1 mm; C = 1.0 mm.
VOLUME 1 12, NUMBER 4 727
Fig. 4. Caprella kuroshio, new species, holotypic male: A, pereopod 5; B, pereopod 6; C, pereopod 7.
Scales: 0.1 mm.
728 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
Fig. 5. Caprella kuroshio, new species, female: A, body, lateral view; B, pereonite 2, lateral view; C,
^nathopod 2; D, abdomen. Scales: A, B = 1.0 mm; C, D = 0.1 mm.
VOLUME 112, NUMBER 4 729
of appendages, a pair of lateral lobes, and nite 2 longer than pereonite 3, with acute
single dorsal lobe. Abdominal appendage ventral projections between insertions of
unsegmented, small, bearing 1 subterminal second gnathopods, and acute lateral pro-
seta. Lateral lob—e with 2 distal setae. jection on insertion of second gnathopod;
Color in life. Specimens occurring on pereonites 3-4 with ventrolateral small pro-
the red algae Gelidium elegans are scarlet jections on anterior end; pereonite 5 with
A
to wine red. single male collected from dorsolateral small projections and lateral
the drifting Sargassum sp. in Suruga Bay is blunt knobs on anterior end; pereonite 6
yellowish. with a pair of dorsal minute projections.
—
Etymology. The specific name is from Antenna 1 (Fig. 6A) longer than a half
the Kuroshi—o current. of the body length; flagellum consisting of
Remarks. Caprella kuroshio resembles 14 segments, shorter than peduncle. Anten-
Caprella penantis Leach, 1814 in general na 2 (Fig. 6A) shorter than peduncle of an-
appearance. However, the former is distin- tenna 1; peduncular segments 3-5 with 2
guishable from the latter by: pereonite 2 rows of dense long setae on ventral surfac-
with ventral projection; male antenna 1 lon- es; flagellar segment 1 with 2 rows of dense
ger than half the body length; basis of male long setae on ventral surface.
gnathopod 2 with mediodistal triangular Upper Hp (Fig. 7A) semicircular, slightly
projection; palmar margin of male gnatho- concave on apical margin, densely pubes-
pod 2 with subdistal poison tooth; female cent. Inner and outer lobes of lower lip
abdomen bearing a pair of appendages. (Fig. 7B) well-developed, round, densely
Caprella kuroshio is also similar to Ca- pubescent on apicomedial margins; outer
prella cicur Mayer, 1903, an endemic spe- lobe with an apicolateral incomplete fold;
cies to South African waters (Griffiths mandibular process developed.
1974a, 1974b, 1975, 1976). The species has Mandible (Figs. 7C-D) without palp. Its
never been redescribed in detail since May- left and right sides consisting of 5-toothed
er's original description. Here, C. cicur is incisor, 5-toothed and irregularly-toothed
redescribed below using the type material lacinia mobilis, and setal row of 3 and 2
C
and compared to kuroshio. plumose setae respectively. Molar process
The type series has been deposited in the well-developed, with 1 plumose seta, and
South African Museum, Cape Town triangular stout projection.
(SAM). Maxilla 1 (Fig. 8A) without inner lobe.
Its outer lobe rectangular, with 7 bifid
Caprella cicur Mayer, 1903 spines on apical margin. Palp 2-segmented.
Figs. 6-10 Its distal segment bearing a row of teeth
and 8 spines on apical margin, 4 setae on
Caprella cicur Mayer, 1903:75, 97, pi. 4
inner margin, rows of setae on ventral sur-
(figs. 5-7), pi. 8 (figs. 3-5); Griffiths,
face.
1974a:255; Griffiths, 1974b:331; Grif-
Inner lobe of maxilla 2 (Fig. 8B) shorter
fiths, 1975:174; Griffiths, 1976:86, 104.
than outer lobe, oval, with 2 rows of nu-
—
Material examined. Syntypes (labeled merous setae on apicomedial margin. The
as "Cotypes"): 1 male, 1 female (SAM outer lobe rectangular, with 2 rows of nu-
1312), Table Bay, Cape Town, on Palinurus merous setae on apical margin.
lalandi, collected by W. F. Purcell, June Maxilliped removed.
1897. — Gnathopod 1 (Fig. 8C) robust. Its ischi-
Description of male. Body (Fig. 6A) um short. Ventral margin of merus pro-
mm
10.40 long. Head with small, acute tri- duced anteriorly, bearing numerous setae on
angular projection directed straight for- anteroventral surface. Carpus expanded
ward; pereonite 1 longer than head; pereo- ventrally, bearing numerous setae. Propo-
730 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
Fig. 6. Caprella cicur Mayer, 1903, syntypes: A, male, lateral view; B, male abdomen, ventral view; C,
female, lateral view; D, female abdomen, ventral view. Scales: A, C = 1.0 mm; B, D = 0.1 mm.
VOLUME 112, NUMBER 4 731
B
Fig. 7. Caprella cicur Mayer, 1903, syntypic male: A, upper lip; B, lower lip; C, left mandible; D, right
mandible. Scales: 0.1 mm.
dus bearing rows of setae on medial sur- poison tooth, with distal triangular projec-
face. Palm bearing a pair of grasping spines tion. Dactylus curved and narrowed distal-
at the proximal comer, its grasping margin ly-
straight, bearing rows of setae. Dactylus fal- Gills (Fig. 6A) present on pereonites 3-
cate. 4, large, elliptical.
Gnathopod 2 (Fig. 6A) attached to per- Pereopods 5-7 fell off.
eonite 2 posteriorly. Basis shorter than per- Abdomen (Fig. 6B) consisting of a pair
eonite 2 in length, bearing laterodistal and of appendages, a pair of lateral lobes, and
mediodistal triangular projections. Ischium single dorsal lobe. Abdominal appendage 2-
bearing lateral triangular projection. Merus segmented, bearing 10 setae; tip of distal
acutely produced anteroventrally. Propodus segment round. Lateral lobe bearing 4 prox-
oblong, 2.5 times longer than basis. Palmar imal and 1 distal setae. Penes large, situated
comer produced, bearing single large grasp- medially.
—
ing spine on apex. Palmar margin without Description offemale. Body (Fig. 6C)