Cinterohynchus Manningi, A New Shrimp (Crustacea: Decapoda: Caridea: Rhynchocinetidae) From The Western Atlantic

6 Pages·1996·2.1 MB·

by  J Okuno

PROCEEDINGS OF THE BIOLOGICAL SOCIETY OFWASHINGTON
109(4):725-730. 1996
Cinetorhynchus manningi, a new shrimp
(Crustacea: Decapoda: Caridea: Rhynchocinetidae)
from the western Atlantic
Junji Okuno
Natural History Museum and Institute, Chiba, 955-2 Aoba-cho, Chuo-ku, Chiba 260, Japan
—
Abstract. A new rhynchocinetid shrimp, Cinetorhynchus manningi, is de-
scribed and illustrated based on two ovigerous female specimens from the
western Atlantic Ocean. The new species is readily distinguishedfrom theother
seven congeners by the absence of arthrobranchs on the second and third per-
eiopods, and constitutes the second rhynchocinetid from the Atlantic ocean.
Shrimps of the family Rhynchocinetidae ural History, Smithsonian Institution,
differ from other caridean shrimps by hav- Washington, D.C.
ing a typically movable rostrum, fine trans-
verse striae on the surfaces of the carapace Cinetorhynchus manningi, new species
and abdominal somites, first two pairs of Figs. 1, 2
—
pereiopods robust, fingers bearing long lat- Rhynchocinetes rigens. Manning, 1961:1
eral and terminal spines, and secondpereio- (in part) (not Rhynchocinetes rigens Gor-
pod with carpus entire, not subdivided. Hol- don, 1936).
thuis (1995) divided the genus Rhynchoci- — USNM
Material. Caribbean Sea:
netes s.l. into two subgenera, Rhynchoci-
277772, holotype, ovigerous female, 8.5
netes H. Milne-Edwards, 1837 and Cineto- mm
CL, Virgin Islands, Eagle Shoal, 10.5
rhynchus Holthuis, 1995. Okuno (in press) USNM
m, 1 Feb 1961; 277773, paratype,
elevated these subgenera to generic rank, mm
ovigerous female, 8.0 CL, Florida, off
and included in Cinetorhynchus six species EUiot Key, Bache Shoals, 4.5 m, 4 May
from the Indo-Pacific and one from the At-
1960, coll. C. —R. Robins.
lantic Ocean. A
Description. rather robust rhyncho-
During this study, I examinedCseveral cinetid shrimp of subcylindrical body form
specimens previously identified as rigens
(Fig. 1).
(Gordon, 1936) captured from various lo- Carapace with many fine transverse stri-
calities in the Atlantic Ocean. In these ma- ae. Three acute teeth on dorsal carina be-
terials, two ovigerous female specimens of hind rostral articulation, anterior tooth larg-
an undescribed species were found. The est. Antennal spine sharply pointed, consid-
new species differs from the other seven erably exceeding anterior margin of cara-
congeners by the absence of arthrobranchs pace. Anterolateral angle of carapace
on the second and third pereiopods. I pro- rounded, without pterygostomian spine.
vide herein the description and illustrations Rostrum (Fig. 2A) well developed, indis-
for this second Atlantic rhynchocinetid tinctly articulated with carapace, distinctly
shrimp. overreaching apex of scaphocerite; length
Method of measuring follows Okuno (in 1.7 times as long as carapace; lateral carina
press). The postorbital carapace length is distinct, reaching end of proximal third of
abbreviated as CL. The abbreviation rostrum, continuous with upper orbital mar-
USNM indicates National Museum of Nat- gin; dorsal margin with 2 large proximal
726 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
Fig. L Cinetorhynchus manningi, new species. Ovigerous female, holotype (USNM 277772, 8.5 mm CL),
lateral view. Scale equals 5 mm.
teeth, 2 small teeth subterminally; ventral dominal somite, ratherconvex dorsally; spi-
margin with 10 teeth, proximal 4 teeth nation of dorsal surface in holotype abnor-
strong, separated by distinct interval from mal, with 2 small spines on right side and
proximal tooth ofdistal series, distal 6 teeth a single small spine at left side, paratype
considerably smaller than proximal four has normal spination, armed with 3 pairs of
teeth, decreasing in size distally. small spines; posterior margin prominent,
Abdominal somites with fine transverse bearing 3 pairs of spinules at each side, in-
striae; pleura of first 3 somites rounded; termediate spinules longest.
fourth somite with small, distinct or indis- Eye with pigmented, rounded cornea,
tinct protrusion posteroventrally; fifth so- eyestalk much slenderer than cornea.
mite with acute protrusion posteroventrally; Antennular peduncle (Fig. 2C) reaching
posterolateral margin offourth and fifth so- end ofproximal third ofrostrum; thickened
mites each with acutely pointed tooth di- part of the upper flagellum reaching to
rected posteriorly; sixth somite rather about rostral apex; proximal segment with
compressed, 0.6 times as long as carapace, distal margin acutely pointed, inner margin
2.1 times as long as its width, with acutely ventrally with acute spine, surface concave;
pointed posteroventral spine directed stylocerite well developed, reaching distal
obliquely backwards, with acute anal spine margin of distal segment; statocyst longi-
between uropodal basicerites. tudinally oval.
Telson (Fig. 2B) 0.6-0.7 times as long as Scaphocerite (Fig. 2D) well developed,
carapace, 1.1-1.2 times as long as sixth ab- reaching midlength ofrostrum, 0.8 times as
VOLUME 109, NUMBER 4 727
Fig. 2. Cinetorhynchus manningi, new species. A-H, ovigerous female, holotype (USNM 277772, 8.5 mm
CL); I, ovigerous female, paratype (USNM 277773, 8.0 mm CL). A, anteriorpart ofcarapace withrostrum; B,
telson and right uropod; C, antennular peduncle; D, scaphocerite; E, first pereiopod; F, second pereiopod; G,
third pereiopod; H, dactylus ofthird pereiopod; I, gill complement ofpereiopods. Scales equal 5mm (A), 2 mm
mm
(B-G, I), and 0.5 (H).
—
728 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
Table 1. Cinetorhynchus manningi, new species. small; distal endite expanded distally,
Branchial formula. broader than proximal endite, with distal
margin with dense setae; proximal endite
Maxillipeds Pereiopods
I II III I II III IV V rounded, with dense setae distally; exopod
— — well developed, caridean lobe slender, fla-
Pleurobranchs 1 1 1 1 1 gellum with numerous setae distally; epipod
AProtdhorborbarnacnhcshs — 1 2 1 large, rounded. Second maxilliped with
Epipods 1 1 1 —1 1 1 1 oval epipod having well developed podo-
Exopods 1 1 1 branch; distal margin of dactylus almost
straight, with long dense setae; propodus
with distal margin rounded, inner margin
long as carapace, 3.3-3.4 times as long as feebly expanded. Third maxillipedreaching
its maximum width; external distal spine distal third of scaphocerite; antepenultimate
acute, reaching level of distal margin ofla- segment with acute spine distolaterally;
mella; basicerite covered with fine trans- penultimate segment 0.3 times as long as
verse striae, with acute spine directed an- carapace, with sparse setae on outer sur-
teriorly and terminal rounded lobe just face; ultimate segment 0.5 times as long as
above spine; carpocerite reaching end of carapace, 1.5-1.6 times as long as penulti-
proximal third of scaphocerite. mate segment, with 6-8 dark homy claws
Branchial formula as shown in Table 1. at apex, covered uniformly with dense setae
Mouthparts typical of genus. Mandible except distal fourth.
with three-segmented palp, distal segment First pereiopod (Fig. 2E) stout, reaching
rounded distally, with short dense setae, in- end ofproximal third ofscaphocerite; chela
termediate segment longest of all, distal slightly compressed, 0.4 times as long as
margin with long sparse setae; incisor pro- carapace, 1.6-1.7 times as long as carpus,
cess stout, with sharp distal teeth; molar palm with short dense setae on proximal
process subcylindrical, broad, with feeble ventral margin, both fingers slightly curved
distal setae and numerous corneous slits. mesially, with dark claws terminally; carpus
First maxilla with feebly bifid slender palp, 0.2 times as long as carapace, distal margin
with denticulate long setae distally; distal truncate, with dense cluster of rather long
lacinia broad, lateral margin convex, with setae.
sparse setae, distal margin straight, with 2 Second pereiopod (Fig. 2F) slenderer
rows of small, stout spinules; proximal la- than first pereiopod, falling short of mid-
cinia broader than distal lacinia, feebly length of scaphocerite; chela 0.3 times as
square distally. Second maxillawithdistinct long as carapace, both fingers slightly
palp, proximally broad, distally slender; curved inside, with dark homy claws ter-
coxal endite broad, distal margin truncate, minally; carpus long, 0.4-0.5 times as long
with numerous long setae distally; distal en- as carapace, 1.5-1.6 times as long as chela.
dite bilobed, upper lobe feebly square dis- Third to fifth pereiopods rather slender,
tally, broader than lower lobe, with dense similar; dactyli (Fig. 2H) with three homy
setae distally, lower lobe with rather claws posterior to terminal largest claw, de-
straightdistal margin, with dense setae; sca- creasing in size proximally; propodi with
phognathite well developed, anterior lobe slightly dense setae on upper margin, with
with feebly square distal end, posteriorlobe sparse spinules at distal % oflower margin,
very slender, inner margin convex, elongat- terminal spinule largest ofall; ischia with 2
ed posteriorly, reaching anterior part of articulated spines on outer surface and low-
third pleurobranch. First maxilliped with er margin. Third pereiopod (Fig. 2G) reach-
elongate, 3-segmented palp, intermediate ing level of distal end of scaphocerite; me-
segment longest of all, distal segment very rus 0.6-0.7 times as long as carapace, 2.0
VOLUME 109, NUMBER4 729
times as long as carpus, with 4-5 articulat- distinguished from the other Atlantic spe-
ed spines on outer surface, proximal spines cies, C. rigens (Gordon, 1936), by having
equidistant, distal spine subterminal, dis- three accessory claws on the inferior mar-
tinctly separated from proximal series, with gin of the dactyli of the third to fifth per-
3 spines on lower margin, and sparse long eiopods, a small posteroventral protrusion
setae dorsodistally; carpus 0.3 times as long on the fourth abdominal somite, a well de-
as carapace, with 2-3 articulated spines on veloped podobranch on the second maxil-
outer surface, with sparse long setae at up- liped and the distinct interval between the
per margin preterminally; propodus 0.5-0.6 proximal four teeth and the distal smaller
times as long as carapace, 1.7 times as long teeth on ventral margin of rostrum. Cine-
as carpus. Fourth pereiopod falling short of torhynchus rigens possesses only two ac-
distal end of scaphocerite; merus 0.6 times cessory claws on the dactyli of the ambu-
as long as carapace, with 4-5 articulated latory pereiopods, unarmed, rounded pos-
spines on outer surface, 2-3 articulated teroventral angle of the fourth abdominal
spines on lower margin; carpus 0.3-0.4 somite, an oblong vestige ofpodobranch on
times as long as carapace, with 2 articulated the second maxilliped, and ventral teeth on
spines on outer surface, with sparse long the rostrum decrease regularly in size dis-
setae at upper margin preterminally; prop- tally (Gordon 1936, Okuno 1996).
odus 0.6 times as long as carapace, 1.6-1.8 The dorsal spination of the telson in the
times as long as carpus. Fifth pereiopod holotype is an abnormal condition, and can
reaching midlength of scaphocerite; merus be attributed to intraspecific variation. The
0.5-0.6 times as long as carapace, 1.5-1.6 paratype does exhibit the normal condition.
times as long as carpus, with three articu- The holotype of the present new species
lated spines on outer surface, a single spine was included in the various specimens re-
situated at distal third oflower margin; car- ported as Rhynchocinetes rigens (= C. ri-
pus 0.4 times as long as carapace, spination gens) by Manning (1961). In his report.
similar to that of fourth pereiopod; propo- Manning (1961) mentioned that there are
dus 0.6 times as long as carapace, 1.6 times two patterns of colorations in the western
as long as carpus. Atlantic population of C. rigens. However,
Uropodal exopod (Fig. 2B) with articu- the type specimens of C. manningi had lost
lated and non-articulated spines at distal their color pattern when I examined them.
third of outer—border. In some publications, beautiful underwater
Coloration. Unknown. photographs have been included of an un-
—
Etymology. The present new species is identified Atlantic rhynchocinetid species,
named for Dr. Raymond B. Manning, in the coloration of which definitively dis-
honor of his valuable contributions to our agrees with that of C. rigens (see Baensch
&
knowledge of western Atlantic rhynchoci- Debelius 1992; Debelius 1983, 1984;
netid shrimp. — Humann 1992). This unidentified species
Distribution. Known only from the Vir- has the red ground color on the whole body
gin Islands a—nd Florida. surface covered with fine pale white spots
Remarks. Cinetorhynchus manningi on the carapace, and five pale white trans-
differs from the other seven congeners by verse bands on the abdominal somites. I
the absence of arthrobranchs on the second have not seen any specimen having the col-
and third pereiopods (Fig. 21), whereas oth- oration mentioned above. Although the col-
er species of Cinetorhynchus have an ar- oration is diagnostic in rhynchocinetids
throbranch on each ofthe first three pereio- (Nomura & Hayashi 1992; Okuno 1994a,
pods. Cinetorhynchus manningi is the sec- 1994b, 1996; Okuno & Takeda 1992), I
ond species of Rhynchocinetidae from the could not determine that ofthe new species
Atlantic Ocean. The present new species is during this study.
—
730 PROCEEDINGS OFTHE BIOLOGICAL SOCIETY OFWASfflNGTON
Acknowledgments Milne-Edwards, H. 1837. Histoirenaturelle des Crus-
taces, comprenant 1'anatomic, la physiologic et
I wish to express my sincere gratitude to la classification de ces animaux. Librairie en-
Dr. F. A. Chace, Jr., for arranging the loan cyclopedique de Rorent, Paris 2:1-532, atlas,
of the Smithsonian specimens. I sincerely pis. 1-42.
thank Dr. R. B. Manning for reading the Nomura, K., & K.-I. Hayashi. 1992. Rhynchocinetes
manuscript. striatus, a new species (Decapoda, C—aridea,
Rhynchocinetidae) from southernJapan. Zoo-
logical Science 9:199-206.
Literature Cited Okuno,J. 1994a. Anewspeciesofhinge-beakshrimp
Baensch,H., &H. Debelius. 1992. MeerwasserAtlas. fRhryonmchtohceiwneesttidearen)P.a—cifTihce(CBreuasgtlaec,ea,RDeceocradpsodao,f
Mergus, Melle, 1216 pp. the Museum and Art Galleries ofthe Northern
Debelius, H. 1983. Gepanzerte Meerestritter. Kernen Territory 11:29-37.
GordonVV,.eerrI.ll1aa9gg81,,49.3EE6ss.AsseerOnnm,,nor11te22hd00e mppkppan..icgrhutrsanofgetnhuessReah.ynKcehroncein- nIs.enhsdreoi1-m9SpW9oe4cbsi(.teCtaryPiRaodchfeiyafnSi:cyc.hsR—othceymiPnanrcteohitcoceecseZidonioecntolgnioscdgoayloeof)(r5,t2fh)re:ao6m2J-an7pte4ahw.-e
netes, with the description ofa new species.
Proceedings of the Zoological Society ofLon- . 1996. Crustacea, Decapoda: Review on the
genus Cinetorhynchus Holthuis, 1995 from the
don 1936:75-88.
HolthuiCsr,usLt.acBe.a D19e9c5a.poNdoateIsI otno IInXd.o—-WZeosotloPgaicsicfhiec IInndBo.-WeRsicthPearcidfiecF(oCragreisd,ea;edR.,hyLncehobceinntehtoisdaed)e.s
Mededelingen, Leiden 69(13):139-151. fondsmeublesdeslagonsdeNouvelle-Caledon-
Humanni,daP.Car19i9b2b.eanReeBfahCarmeaast.ureNeIdwentWiofircladtioPnu:blFilcoar-- i,e&(inMp.resTsa)k.eda. 1992. Description of a new
tions, Jacksonville, Florida, 320 pp. hinge-beak shrimp, Rhynchocinetes conspici-
Manning, R. B. 1961. Notes on the caridean shrimp, ocellus, from southern Japan, with desig—nation
Rhynchocinetes rigens Gordon (Crustacea, De- ofthe lectotype of/?, uritai Kubo, 1942. Bul-
capoda), in the western Atlantic-—Notulae Na- letin ofthe National Science Museum, seriesA
turae (348):1-7. (Zoology) 18(2):63-72.