Caprella arimotoi, a new species (Crustacea: Amphipoda, Caprellidea) from the Seto Inland Sea, Japan

7 Pages·1993·3.1 MB·

by  I Takeuchi

PROC. BIOL. SOC. WASH.
106(1), 1993, pp. 115-121
CAPRELLA ARIMOTOI, A NEW SPECIES
(CRUSTACEA: AMPHIPODA: CAPRELLIDEA)
FROM THE SETO INLAND SEA, JAPAN
Ichiro Takeuchi
—
Abstract. Caprella arimotoi is described based on the material collected
from the red alga Pterocladia capillacea (Gmelin) on the Mukaishima Island
in the Seto Inland Sea. The new species is close to C. verrucosa Boeck, 1872,
but differs in having few plumose setae on antenna II, forwardly vented pro-
jection on head and elongate gills. Caprella (Spinicephala) pseudoverrucosa
(nomen nudum) mentioned in Arimoto's essay of 1978 is synonymous with
the present species.
Caprella is the largest genus of the sub- Caprella arimotoi, new species
order Caprellidea (Crustacea: Amphipoda), Figs. 1-3
widely distributed from temperate to boreal
Caprella {Spinicephala) verrucosa, Arimo-
regions occurring primarily on seaweeds,
to, 1976, 122-129 (in part), fig. 67-D. (non
seagrasses, and hydroids. So far about 130
Caprella verrucosa Boeck, 1872)
speciesofthisgenushavebeenreported (e.g.,
McCain 1968; Laubitz 1970, 1972; McCain Caprella {Spincephala [sic.]) pseudoverru-
& cosa Arimoto, 1978, 14, fig. 7C. (nomen
Steinberg 1970; Vassilenko 1974; Ari-
nudum)
moto 1976; Takeuchi 1989). During my
short visit to the Mukaishima Marine Bi- Material examined.—HoXoXypt (NSMT
ological Station ofHiroshima University in 11191), male from Pterocladia capillacea
June 1989, the author found numerous ma- (Gmelin) Bomet & Thuret found at the
ture individuals ofCaprella on the red alga highest level ofsubtidal zone, Mukaishima
Pterocladia capillacea (Gmelin) in the sub- Island, Seto Island Sea (34°22'N, 133°13'E),
tidalzone. Acloseexamination ofthose ma- June 6, 1989, coll. I. Takeuchi. Allotype
terials revealed that some ofthem are iden- (NSMT 11192), female collected together
NSMT
ticalwith whathasbeencalled "youngmale" with holotype. Paratypes: 1 1 193 (14
C USNM
of {Spinicephala) verrucosa Boeck, 1872 males and 4 premature females),
C
in Arimoto (1976) and with (5.) pseu- 251762 (10 males and 1 mature and 2 pre-
NMCC
doverrucosa in Arimoto (1978). In this pa- mature females), and 1992-0603 (10
per, the specimens are described as a new males and 1 mature and 3 premature fe-
species. males), all collected together with holotype.
The type specimens have been deposited Arimoto's private collection No. 877-8, 1
in the National Science Museum in Tokyo male from Sargassum sp., Tsushima Is-
(NSMT), National Museum ofNatural His- lands, December 1946 (?).
tory in Washington, D.C. (USNM), and Ca- Diagnosis.—Head with triangular for-
nadian Museum of Nature in Ottawa wardly pointing projection above eye. Pere-
(NMCC). The definition ofmature stages in onites II to VI each with 1 or 2 rounded
females was referred to Takeuchi & Hirano dorsal projections. Antenna II oflarge male
(1991). with 4-5 pairs ofplumose setae on each of
116 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
V
peduncular segments II and III. Basis of Basis ofpereopod withlaterally expanded
gnathopod II shorter than halfofpereonite projection carrying granulations; merus ex-
II; propodus oval, palm with pointed pro- panded on outer side; palm of propodus
jection near proximal end and shallow tri- convex, coarsely setose, withapairofgrasp-
angular projection near distal end. Gills ing spines on a small knob near proximal
V
elongate, small. Propodus of pereopods end. Features ofpereopods VI andVII close
V
to VII each with a pair ofproximal grasping to that ofpereopod V. Pereopods to VII
spines. longerprogressively; pereopodVIIespecial-
Description. —Holoiype (Male; Figs. lA, ly large, twice as long as pereopod VI.
2A-F', 3A-H). Body length 6.97 mm; length Abdomen. Distal segment of appendage
ofhead 0.45 mm; length ofpereonites I to oval, shallowly divided into 3 apical teeth;
VII 0.34, 1.42, 1.37, 1.23, 1.05, 0.66, and basal segment with 5 or 6 setae surrounding
0.47 mm, respectively. Head anteriorly distal segment. Lobes bearing several long
round; dorsal projection curved and point- setae. Penes medial.
ed forward from posterior end. Pereonite I Mouthparts. Inner plate of maxilliped
with small posterodorsal projection; pere- round and distally expanded with 2 spini-
onites II to IV each bearing a mid-dorsal form setae on distal margin and a facial row
and a posterodorsal blunt rounded projec- of several plumose setae; outer plate, sub-
V
tion. Pereonite with a minute anterolat- equal to inner plate, round and bearing 2
eral and a mid-dorsal blunt rounded pro- curved spiniform setae and 3 long setae on
jection. Pereonite VI with a mid-dorsal inner margin; segment II of palp with
triangular projection. scarcely setose inner margin; segment III
Antenna I about Vi of body length. Pe- expanded distally, scarcely setose on lateral
duncular segments longer in the order ofII, face; segment IV, longerthan III, with sharp
I, and III; flagellum composed of 11 seg- claw. Outer plate of maxilla I rectangular
ments and somewhat longer than peduncle. and slightly curved, with 7 spiniform teeth;
Antenna II about % length of antenna I. distal segment of palp rectangular with 4
Peduncular segments III and IV fringed with spiniform teeth on distal margin, 3 stout
5 pairs of plumose setae and with 5 pairs setae on distal part of inner margin, and a
and a plumose setae, respectively; flagellar row of 5 long setae followed by a short seta
segment I with 4 pairs of short plumose on lateral face. Maxilla II with oval inner
setae; flagellar segment II with a short plu- and rectangular outer plate; both with
mose setae followedby 3 setae ondistalend. densely setose margins. Incisor ofleft man-
Gnathopod I with propodus twice as long dible divided into 6 teeth; lacinia mobilis
as width; palm serriform, setose with a pair separated into 5 teeth followed by 3 setae;
ofgrasping spines near proximal end. molarwithalongsetanearouteredge. Right
Gnathopod II with vestigial coxa insert- mandible with 5-toothed incisor, lacinia
ing V3 from anterior margin ofpereonite II. mobilis carrying minute teeth on middle
Basis about % of pereonite II. Propodus marginfollowedby 2 setae; molarlarge, with
oval, V3 of pereonite II. Palm with 2 pro- along setaandbushybundle ofsetae. Upper
jections; proximal one V^ from proximal end, lip finely setose. Inner lobe of lower lip
pointing distally, and carrying 4 setae on round, finely setose on distal part.
basal part; distal one low triangular and Female(allotype, figs. IB, 2G-I, 31). Body
sparsely setose. Dactylus stout, distal % of length 5.91 mm. Head 0.43 mm. Pereonites
inner margin serrated. I to VII 0.22, 1.12, 0.97, 0.86, 0.87, 0.52,
Gills small, elongate, 3 times longer than 0.49, and 0.44 mm, respectively.
width. Gnathopod II situated near anterior of
V
Pereopods to VII with vestigial coxae. pereonite II. Basis slightly shorter than V2
VOLUME NUMBER
106, 1 117
Fig. 1. Caprella arimotoi, n. sp. from Mukaishima Island in the Seto Inland Sea. A, holotype (male), 6.97
mm; B, allotype (female), 5.91 mm.
ofpereonite 11. Propodus oval, subequal to (Arimoto 1976) and Amatsu-Kominato
basis; palm smooth, convexandsetose, with (Takeuchi 1989; as Caprella sp. C), Chiba.
a grasping spine near proximal end. Remarks.—The present new species is
Oostegite III setose on margin; oostegite close to Caprella verrucosa Boeck, 1872 in
IV minutely setose on anterior margin and having blunt dorsal projections on pereon-
moderately on posterior margin. Gills on ites I to VI, short basis and oval-shaped
pereonite III oval and those on pereonite propodus in gnathopod II, and grasping
IV smaller, elliptical. Abdomen with a pair spines on pereopods V to VII.
oflobes without setae. Caprella verrucosa was first reported from
Etymology.—The specific name, arimo- somewhere near San Francisco, California
toi, is in honor ofthe late Dr. Ishitaro Ari- (Boeck 1872), and later recorded from both
moto, who made contributions to the tax- sides of the North Pacific; from the Queen
onomy of the Japanese caprellidean Charlotte Islands, British Columbia to Santa
&
amphipods and was the first person to find Catalina Island, California (Dougherty
the present species. Steinberg 1953, Laubitz 1970, McCain &
Localities.—Type locality: Mukaishima Steinberg 1970, Martin 1977, MarelH 1981),
Island, Seto Inland Sea (34°22'N, 133°1 3'E). in the east, and from the Tsugaru Straight
Others: Tsushima Islands, and Tateyama to the Kyusyu Islands along both Japanese
PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
118
0.20mm
A:
0.10mm
B:
C-G: 0.20mm H, 0.20mm
I:
Fig. 2. Caprella arimotoi, n. sp. from the Mukaishima Island in the Seto Inland Sea. Holotype (male), 6.97
mm
.„m. A, antenna II; B, gnathopod I; C, gnathopod II; D, pereopod V; D', coxa ofpereopod V; E, pereopod VI;
E', coxa ofpereopod VI; F, pereopod VII; F', coxa ofpereopod VII. Allotype (female), 5.91 mm. G, gnathopod
II; H, gill and oostegite on pereonite III; I, gill and oostegite on pereonite IV.
VOLUME NUMBER
106, 1 119
Fig. 3. Caprella arimotoi, n. sp. from the Mukaishima Island in the Seto Inland Sea. Holotype (male), 6.97
mm. A, maxilliped; B, maxilla I; C, maxilla II; D, right mandible; E, left mandible; F, upper lip; G, lower lip;
H, abdomen. Allotype (female), 5.91 mm. I, abdomen.
coasts (Utinomi 1943, 1947, 1964; Arimoto euchi 1989) and British Columbia (Laubitz
1976; Takeuchi 1989) and the south coast 1970) with the following characters: 1) An-
ofthe Korean Peninsula (Kim & Lee 1975, tenna I equal to Vi ofthe body length {% in
Lee 1988) in the west. C. verrucosa), 2) pedunclar segments ofan-
C
Mature males of arimotoi can be sep- tenna I slender, each about 4 times longer
C
arated from those of C. verrucosa from the than width (2 to 3 times in verrucosa),
Japanese coast (Utinomi 1943, 1947; Tak- 3) antenna II carrying 4-5 pairs ofplumose
120 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
setae on peduncular segments II and III prella sp. C in Takeuchi (1989) is also syn-
(more than 8 pairs oflonger plumose setae onymous with C. arimotoi.
in C. verrucosa), 4) mid-dorsal projection In conclusion, Caprella arimotoi, n. sp.
C
on the head curved forward, (straight for- clearly differs from verrucosa in several
C
ward in verrucosa), 5) lacking ventrolat- characters, and the slender "young male"
eral projections on pereonites III to IV (C. of C. {Spinicephala) verrucosa in Arimoto
verrucosa with distinct ventrolateral projec- (1976) and C. {S.) pseudoverrucosa in Ari-
C C
tions on pereonites III and IV), 6) in moto (1978) arejunior synonyms of ari-
verrucosa, additional paired projections motoi.
on pereonites IV to V, and 7) gills 3 times
C
longer than width (1.5 times longer in Acknowledgments
verrucosa).
C The author thanks Prof. Ju-shey Ho and
The author examined the specimens of
Dr. M. Takeda for reviewing the manu-
verrucosa collected from Vancouver Island,
script. Dr. H. Katayama for use ofthe lab-
British Columbia, and deposited at the Ca-
nadian Museum of Nature (NMC 10867). oratory facility at the Mukaishima Marine
Biological Station ofHiroshima University,
The characters given above were found ap-
Dr. S. Yamato for assistance in the field,
plicable also to these Canadian specimens.
Arimoto (1976) described two types ofC. and the family of the late Dr. I. Arimoto
for the loan of the specimens. Mrs. D. R.
(Spinicephala) verrucosa from the Japanese
my
Laubitz kindly arranged for short visit
coast. His robust type is identical with C. to the Canadian Museum of Nature (for-
verrucosa as described by Utinomi (1943,
merly National Museum of Natural Sci-
1947) and Takeuchi (1989), while the slen-
ences) in Ottawa. This study was partially
der type belongs to the new species. Ari-
supported by the Research Aid of Inoue
moto (1976) statedthatthe slendertyperep-
C Foundation for Science, Tokyo.
resented the young stage of verrucosa,
mm
although its body was 6.5 long. Later, Literature Cited
in his essay (Arimoto 1978), he showed the
lateral view of slender type labelled "Ca- Arimoto, I. 1976. Taxonomic studies of caprellids
prella {Spincephala [sic.]) pseudoverrucosa.^^ (tChreusJtaapcaena,esAempahnidpoaddjaa,ceCnatprewlaltiedrase.)—foSpuencdiailn
Duringthe reexamination ofArimoto's col-
Publications from the Seto Marine Biological
lection, a specimen labelled "C. pseudover- Laboratory, Series III:i-v + 1-229.
rucosa'' from the Tsushima Islands was 1978. NipponnoWarekara [TheCaprellidea
.
found. The specimen, representing a large ofJapan].—DobutsutoShizen [AnimalandNa-
mm
mature male of 8.79 long, is identified ture] 8:10-15 (in Japanese).
Boeck, A. 1872. Bidrag til Califomiens Amphipo-
with C. arimotoi. This indicates that Ari-
defauna.—Forhandlinger i Videnskabs-selska-
moto had come to the same conclusion as bet i Christiania: 32-51.
the present author that the slender type was Dougherty, E. C, & J. E. Steinberg. 1953. Notes on
C
not ajuvenile stage of verrucosa, but rep- theskeletonshrimps(Crustacea: Caprellidae)of
resented another species. His essay (Ari- California.—Proceedings of the Biological So-
moto 1978), however, was written in Jap- ciety ofWashington 66:39-49.
International Commission on Zoological Nomencla-
anese and without any taxonomic account. ture. 1985. Pp. i-xx + 1-338 z>7 W. D. L. Ride
Thus, it does not constitute a valid publi- et al., eds., International code ofzoological no-
XX
cation as specified by the International menclature. Third edition adopted by the
Commission on Zoological Nomenclature general assembly ofthe International Union of
A Biological Sciences. University of California
(1985; Article 8-(a)-(l) on pp. 12-13).
C Press, Berkeley and Los Angeles, U.S.A.
taxonomic account of (S.) pseudoverru- Kim, H. S., & K. S. Lee. 1975. Faunal studies onthe
cosa was never prepared by Arimoto. Ca- genus Caprella (Crustacea: Amphipoda: Ca-
VOLUME NUMBER
106, 1 121
prellidae) in Korea.—Korean Journal of Zool- Takeuchi, I. 1989. Taxonomicandecological studies
ogy 18:115-126. ofthe Caprellidea (Crustacea, Amphipoda) in-
Laubitz, D. R. 1970. Studies on the Caprellidae habiting the Sargassum zone. Doctoral thesis.
(Crustacea,Amphipoda)oftheAmericanNorth Faculty of Agriculture, The University of To-
Pacific—National Museums of Canada, Pub- kyo, Tokyo, 244 pp (in Japanese).
lications in Biological Oceanography 1:1-89. ,&R.Hirano. 1991. Growthandreproduction
1972. The Caprellidae (Crustacea, Amphip- ofCaprelladanilevskii(Crustacea: Amphipoda)
.
oda) ofAtlantic and Arctic Canada.—National reared in the laboratory.-Marine Biology 1 10:
Museums ofCanada, Publications in Biological 391-397.
Oceanography 4:1-82. Utinomi, H. 1943. Caprellids obtained in Onagawa
Lee, K. S. 1988. Fauna ofCaprellidae (Amphipoda) Bay, northern Japan.—Science Reports of To-
of Cheju Island and its adjacent waters, Ko- hoku University, Series 4. Biology 17:271-279.
rea.—The Korean Journal ofSystematic Zool- 1947. Caprellidae ofJapan and adjacent wa-
.
ogy, Special Issue 2:97-106. ters.—Seibutsu Supplement 1:68-82 (in Japa-
Marelli, D. C. 1981. New records for Caprellidae in nese).
California, and notes on a morphological vari- . 1964. Caprellidea. Pp. 11-15, pis 1-3 in T.
ant of Caprella verrucosa Boeck, 1871.—Pro- Kikuchi, ed., Fauna and flora ofthe sea around
ceedingsoftheBiologicalSocietyofWashington theAmakusaMarineBiologicalLaboratory. Part
94:654-662. V. Amphipod Crustacea. Amakusa Marine Bi-
Martin, D. M. 1977. A survey ofthe family Caprel- ological Laboratory, Kyusyu University, Ku-
lidae(Crustacea,Amphipoda)fi-om selectedsites mamoto, Japan (in Japanese).
along the northern California Coast.—Bulletin Vassilenko, S. V. 1974. [Caprellids ofthe seas ofthe
ofthe SouthernCaliforniaAcademyofSciences USSR and adjacent waters.]—Opredeleliteli po
76:146-167. Faune SSSR 107:1-288 (in Russian).
McCain,J. C. 1968. TheCaprellidae(Crustacea:Am-
phipoda)oftheWesternNorthAtlantic.—Unit- Otsuchi Marine Research Center, Ocean
edStatesNational Museum Bulletin 278:i-vi +
Research Institute, The University of To-
1-147.
, & J. E. Steinberg. 1970. Amphipoda I. Ca- kyo, Akahama, Otsuchi, Iwate 028-11, Ja-
prellidea I. Fam. Caprellidae. Pp. 1-78 in H.- pan.
E. Gruner& L. B. Holthuis, eds., Crustaceorum
Catalogus, Pars 2. Dr. W. Junk Publishers, The
Hague, The Netherlands.