Chelomalpheus Koreanus, A New Genus And Species Of Snapping Shrimp From Korea (Crustacea : Decapoda : Alpheidae)

6 Pages·1998·1.8 MB·English

by  W Kim

PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
111(1):140-145. 1998.
Chelomalpheus koreanus, a new genus and species of snapping
shrimp from Korea (Crustacea: Decapoda: Alpheidae)
Won Kim
DepartmentofMolecularBiology, SeoulNationalUniversity, Seoul, 151-742, Korea
—
Abstract. Chelomalpheus koreanus, anew genus and species, isdescribed
on the basis of three specimens collected from the Yellow Sea, Korea. The
new genus differs from all other genera ofAlpheidae by the combination of
thefollowingcharacteristics: thepresenceofanotchontheinferiormarginof
carapace, the presence of an articulated movable plate on the posteroventral
margin of the sixth abdominal somite, and the presence ofroundly elongate
immovableteeth on the transverse sutureoftheuropodal exopod.
Duringrecentcollectionsinamud-sandy maxilliped with coxa bearing one arthro-
beachintheYellow Sea, Korea, specimens branch.
of a new genus and species of the family Firstpereopodssimilarinshapeandsize,
Alpheidae were found. Thenew genus and lackingsexualdimorphism.Chelaelongate,
species is described herein. Holotype and deflexedbelownearbaseofimmovablefin-
ovigerous female paratype are depositedin ger. Movablefingershallowlyarchedalong
the National Museum of Natural History, superior margin, bearing 2 blunt teeth on
Smithsonian Institution, Washington, D.C. inferior margin. Immovable finger with 1
(USNM). blunt tooth at middle of superior margin
and anothersmall toothproximally.
Chelomalpheus, new genus Second pereopods equal, similar, and
— slender. Carpus 5-segmented: first segment
Definition. Generalbodyform asusual as long as fifth, about 2 times as long as
formembers ofthe family Alpheidae. second; second, third, and fourth almost
Body slightly compressed, surfaces equal in size.
smooth and glabrous. Ambulatory pereopods slender, dactyli
Rostrum very small and acute. Orbital simple. Thirdpereopodratherslender;dac-
hoods absent. Carapace with anteroventral tylus acute, slender; ischium with 1 mov-
margin bluntly rounded, not produced an- able spine.
teriorly; inferiormarginwithabroadnotch Abdomen with pleura of first four seg-
at middle part; cardiac notch well devel- mentsbroadlyroundedinbothsexes. Sixth
oped. segment with posteroventral margin with
Eyes well developed, cornea fully ex- articulated, movable triangular plate. Ap-
posed dorsally and laterally. pendix masculina far overreaching distal
Antennules slender. Stylocerite falling end ofappendix interna.
slightlyshortofmiddleofsecondsegment. Telson slender, with 2 pairs of dorsal
Scaphocerite normal, with distal spine and spines located laterally.
innerblade. Carpoceriteslightlyoverreach- Uropodalexopodbearing 1 slendermov-
ing distal endofantennularpeduncle. Bas- able spine laterally; transverse suture (di-
iceritewith sharp lateral spine. aeresis)withabout 10immovableteethand
Mouthparts similar to those in Alpheus endinginsmallimmovable spineonlateral
Fabricius, 1798(Kim&Abele 1988).Third margin.
VOLUME 111,NUMBER 1
Fig.1. Chelomalpheuskoreanus,newspecies,holotypemale,USNM285514,cl4.7mm,lateralview.Scale,
2.0mm.
Epipodspresen—tonfirstthreepereopods. then almost straight; anteroventral margin
Type species. Chelomalpheus korean- bluntly rounded, not produced anteriorly;
us, new specie—s. inferior margin of carapace with a broad
Etymology. The generic name is de- notch at middle part near basis of second
rived from the Greek word "cheloma," peropod; cardiac notch well developed.
meaning "notch," indicating the presence Eyes well developed, cornea fully ex-
ofanotchontheinferiormarginofthecar- posed dorsally andlaterally.
apace. Antennules (Fig. 3A) slender. First seg-
mentlongerthanwide,withshallowcarina
Chelomalpheuskoreanus, new species extending from ventral inner margin. Sec-
Figs. 1-3 ond segment elongate, about 3.3 times as
Material examined.—Holotype (USNM long as broad, 1.9 times as long as visible
285514): Male, cl 4.7 mm, Daecheon, the partoffirst segmentand3 times aslongas
YellowSea,Korea(36°19'05"N, 126°30'25" third segment. Stylocerite narrowing to
E), from pool dug in mud-sandy beach, long sharp point, falling slightly short of
coll.SaHeungKim,6Jun 1996.Paratypes: middle ofsecond segment.
1 male (cl4.0mm), 1 ovigerousfemale(cl Scaphocerite slightly more than 3 times
4.5 mm, USNM 285515), same locality as as long as broad. Lateral margin almost
holotype. — straight. Distal spine directing forward,
Description. Body (Fig. 1) slightly overreachingdistalmarginofsecondanten-
compressed, surfaces smooth andglabrous. nularsegment.Innerbladebroadlyrounded
Rostrum (Figs. 1, 3A) very small, acute, distally, with no cleft between inner blade
and triangular in dorsal view, and clearly and distal spine.
carinateforshortdistanceposteriorly. Carpocerite slightly overreaching distal
Carapace (Fig. 1) with anterior margin endofantennularpeduncle. Basiceritewith
shallowlyconcavenearbaseofrostrumand broadly based, sharp, lateral spine.
142 PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
(i^>
Fig.2. Chelomalpheuskoreanus,newspecies,holotypemale,USNM285514,cl4.7mm:A,mandible;B,
firstmaxilla;C,secondmaxilla;D,firstmaxilliped;E,secondmaxilliped;F,thirdmaxilliped.Scale = 1 mm;
F,0.5mm:A,B,C,D,E.
Mandible (Fig. 2A) with incisorprocess row, attached as strip to penultimate seg-
rather broad and bearing 5 teeth on distal ment;exopodwelldeveloped;epipodfairly
margin; molarprocess bearing someridges large and elongate. Third maxilliped (Fig.
providedwith beds ofsofthairs; palpcon- 2F) slender, extending to almost distal end
sisting of2 distinctsegments. Firstmaxilla of carpocerite; ultimate segment tapering
(Fig. 2B) with upper endite broad, bearing distally with 3-4 small spinules distally,
spinulesondistolateralmargin;endopodbi- about 1.8timesaslongaspenultimate;pen-
lobed, eachlobebearing singlestrongseta. ultimate segment rather elongate, about 4
Secondmaxilla(Fig. 2C)withupperendite times as long as broad neardistal end; an-
entire, provided with setae; lower endite tepenultimate segment rather elongate,
small, bearing 1 seta; endopod narrow and about 7.8 times as long as broad; exopod
simple; scaphognathite large, anterior lobe reaching to far short ofdistal end ofante-
narrow, posterior lobe large. First maxilli- penultimate segment; coxa with 1 arthro-
ped (Fig. 2D) with endites entire, bearing branch.
row of setae on marginal region; exopod First pereopods (Fig. 3B, C) similar in
with exopodal (caridean) lobe narrow but shape and size and no sexual dimorphism,
distinct; endopod slenderwith single,long, almost reaching to tip of lateral spine of
simple setaon distal margin; epipod large, scaphocerite. Chela (Fig. 3D) elongate, 3.6
elongated oval shape with lateral margin timesaslongasbroad,deflexedbelownear
broadly concave. Second maxilliped (Fig. base of immovable finger; fingers slightly
2E) withultimate segmentofendopodnar- deflexedinternally,occupyinglessthandis-
VOLUME 111,NUMBER 1 143
Fig.3. Chelomalpheuskoreanus,newspecies,holotypemale,USNM285514,cl4.7mm:A,anteriorregion,
dorsalview:B,rightfirstpereopod,outerview;C,same,innerview;D,same,chela,outerview;E,rightsecond
pereopod:F.rightthirdpereopod;G,rightfourthpereopod;H,telsonandrighturopod;I,rightsecondpleopod.
Scalea= 1 mm:A;scaleb = 1 mm:E,H,0.5mm: D,I;scalec = 1 mm:B,C,F,G.
1
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tal0.3ofchela;palmentire,subcylindrical, ed, fairly large, movable, triangular plate.
about 2.6 times as long as broad; movable Appendix masculina (Fig. 31) far over-
fingershallowlyarchedalongsuperiormar- reachingdistalendofappendixinterna.
gin, bearing 2 blunt teeth on inferior mar- Telson(Fig. 3H) slender, about2.3times
gin;immovablefingerwith 1 blunttoothat aslongasbroadatanteriorend,lateralmar-
middle ofsuperiormarginfitting spacebe- gins almost straight; posteriormargin con-
tween2immovableteethofmovablefinger vex; 2 pairs ofdorsal spines locatedrather
andanothersmalltoothproximally.Carpus laterally, at about 0.2 and 0.5 of telson
more than 2 times as long as broad near length; posterior margin with 2 pairs of
distal end with about 6 short tufts ofsetae movable spines located laterally, lateral
alonginferiormargin. Merus about4times spine very small, equal to 0.2 oflength of
as long as broad; superior margin with medial.
about6immovablesmallspinulesalongsu- Uropodal endopod (Fig. 3H) bearing
perior margin and with about 6 short tufts small spinules on distal margin. Uropodal
of setae along inferior margin. Ischium exopod bearing 1 slender movable spine
about 2.5 times as long as broad, with5-6 laterally; transverse suture (diaeresis) with
very small spinules along superiormargin. about 10roundlyelongateimmovableteeth
Secondpereopods (Fig. 3E) equal, simi- and ending in small immovable spine on
lar,andslender,notreachingtolateralspine lateralmargin—.
of scaphocerite. Fingers of chela about as Variation. Littlevariationexistsamong
long as palm. Carpus 5-segmented: first the three specimens. Inmales, thenotchof
segment about 2 times as long as second; theinferiormarginofthecarapaceisdeeper
second, third, fourth almost equal in size; compared to the female. In the female, the
fifth segment almost as long as first. carpocerite almostreachestothedistalend
Third pereopod (Fig. 3F) rather slender. of antennular peduncle. The number of
Dactylusacute, slender.Propodusabout6. movable spines on the inferior margin of
times as long as broad, about 2.4 times as the propodus in the third and fourth per-
long as dactylus and 1.3 times as long as eopods varies—from 2-4 in males.
carpus, with 2 smallmovable spinesonin- Etymology. The specific name is after
feriormargin and apair at distal end. Car- the Republic o—fKorea.
pus with 1 small movable spine at distal Discussion. The specimens referred to
end ofinferior margin, 4 times as long as this new genus key out to Potamalpheops
broad. Merus about 5.3 times as long as and Pseudathanas in Holthuis' (1993) ge-
broad, 2 times as long as carpus, unarmed. neric key, though they are easily distin-
Ischiumwith 1 ratherstrongmovablespine. guishedfrommembersofanyknowngenus
Fourth pereopod (Fig. 3G) almost same in the family Alpheidae by having a notch
as third pereopod. Propodus with 4 mov- ontheinferiormarginofthe carapace.The
ablespinesoninferiormarginandapairat present specimens obviously donotbelong
distal end. Ischium with 1 rather strong to Potamalpheops Powell, 1979 (Bruce
movable spine. 1993, Yeo&Ng 1997)becausetheylacka
Fifth pereopod similar to fourth pereo- tooth behind the eye, nor to Pseudathanas
pod, but much more slender. Ischium with Bruce, 1983 because they have immovable
no movable spine. teethinsteadofarowofmovablespineson
Abdomen (Fig. 1) with pleura of first the transverse suture (diaeresis) oftheuro-
foursegmentsbroadlyroundedinbothsex- podal exopod. The present new species is
es. Pleuron of fifth somite subrectangular easily distinguished from the species of
onposteroventralmargin.Sixthsegmental- AthanasLeach, 1814 by having very short
most as long as fifth, posterolateralmargin rostrumandbyhavingnosupracorneal,ex-
acute, posteroventral marginwith articulat- tracomeal, and infracorneal spines usually
VOLUME 111,NUMBER 1
present with varying degrees of develop- genus,newspecies,analphe—idshrimpfromthe
ment inAthanas. The present new species northernterritory,Australia. JournalofCrus-
taceanBiology3:463-471.
misataelsodediMfafenr,ent18f8r8om(Cthhaecesp1e9c8i8es, oHfolAtuhtuoi-s c.ea:19D9e3.capPoodtaa:m—aAllpphheeiodpase)d,artwhientiheinrsdisIn(dCor-uWsetsat-
1993) in having an articulated movable Pacificspecies. ProceedingsoftheBiological
plate on the posteroventral margin of the SocietyofWashington 106:698-704.
sixth abdominal segment. Therefore this Chace,E A.,Jr. 1988. TheCarideanshrimps(Crus-
tacea: Decapoda) of the Albatross Philippine
sahnryiomfptshpeeckineoswins esapseicliyesdiosftitnhgeuifsahmeidlyfrAolm- deaxep.ed—itSimoin,ths1o9n0i7a-n191C0o,ntrpiarbtut5i:onfsamtiolyZAoloplhoegiy-
pheidae by the combination ofthe follow- 466:1-99.
ing characteristics: thepresence ofanotch Fabricius, J. C. 1798. Supplementum entomologiae
ontheinferiormarginofcarapace;thepres- Holthuissy,stLe.maBt.ica1e9.93H.afTnhieae,re5ce7n2tpgpe.neraoftheCari-
ence ofan articulatedplateonthepostero- dean and Stenopodidean shrimps (Crustacea,
ventral margin of sixth abdominal somite; Decapoda):withanappendixontheorderAm-
and the presence of roundly elongate im- phionidacea. [C.H.J.M.Fransen&C.vanAch-
movable teeth on the transverse suture of terberg, editors]. Nationaal Natuurhistorisch
uropodal exopod. Kim,WM.,us&euLm.,G.LeAibdeelne,.321898p8p..Thesnappingshrimp
genusAlpheusfromtheeas—ternPacific(Decap-
Acknowledgments oda: Caridea: Alpheidae). Smithsonian Con-
tributionstoZoology454:1-119.
I am grateful to Mr. Sa Heung Kim for Leach, W. E. 1814. Crustaceology. in D. Brewster,
collecting the specimens. This work was TheEdinburghEncyclopaedia7:383-437.
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totheknowledgeofthealpheidshrimpofthe shrimp genus Potamalpheops Powell, 1979,
Pacific Ocean, partV: Th—e Indo-Pacific mem- (Crustacea: Decapoda: Caridea: Alpheidae)
bersofthegenusAthanas. PacificScience14: fromSoutheas—tAsia,withdescriptionsofthree
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