A New Hemerocostine Fish,Osopsaron Karlik(Percophidae, Trachinoidei)From the Nazca Submarine Ridge

魚類学雑誌 Japanese Journal of Ichthyology 31巻4号1985年 Vol.31,No.41985

A New Hemerocostine Fish,Osopsaron karlik(Percophidae, Trachinoidei)from the Nazca Submarine Ridge

Nikolay V.Parin (Received February7,1984)

Abstract A new species of the Hemerocoetinae,Osopsaron karlik is described from11specimens 20-42mm in SL collected on the Nazca Submarine Ridge at300-395m.It differs from other species of Osopsaron,O.verecundum(Jordan et Snyder)of Japan,O.incisum(Gilbert)of Hawaii and O.natalensis Nelson of Natal in number of gill rakers and fin rays,peculiar pigmentation of first dorsal fin,and longer head.

dorsal fin with 19-20 unbranched soft rays. Eleven small specimens belonging to the Anal fin with 22-23 soft rays,all except the percophid subfamily Hemerocoetinae were extreme ones branched.Pectoral fin rays19 dredged at two unnamed seamounts of the 20.Head 2.6-2.8 in SL,length of snout 1.3 Nazca Submarine Ridge in the eastern South 1.7 in orbit length.Dorsal operculum in the Pacific.They are described here as the types of a new soecies.Osopsaron karlik. eye present.Gill rakers 11-14.Vomerine In the following description,terminology as teeth well developed. well as methods of counts and main measure Description.Body elongate,subcylindrical, ments follow Nelson(1982).Data of the para tapering to tail.Scales large,cycloid,deciduous; types(when different from holotype)are given two rows between base of dorsal fins and lateral in parentheses. line;(about30to31in a straight lateral line as counted partially from scale pockets in 2 para Osopsaron karlik sp.nov. types).(Vertebrae 32 including hypural plate Fig.1) ( in stained paratype). Pteropsaron incisum(?):Parin,1982:75-76,fig.2 Head large,depressed;no evidence of scales brief description( from the same specimens as anywhere(a few scales traced on opercles in treated in the present paper). larger paratypes).Mouth terminal,with lower Holotype.ZIL(Zoological Institute of the Academy jaw slightly shorter than upper.Upper jaw of Sciences USSR,Leningrad)46748,30.5mm in protractile,ending below center of eye,its standard length(SL);Nazca Ridge(25•‹48'S, posterior end slightly notched,anterior tip of 86•‹13'W)at 300 m,October 3,1980;benthic dredge; maxillary with strong spine directed forward, coll.S.D.Chistikov.

Paratypes.ZIL 46749,2 specimens 24mm protruding through skin.Eye with dorsal operculum(=dorsal iris flap or iris lappet;see (damaged)and 29mm SL,same data as holotype; ZIL 46750,4 specimens 20-42mm SL(one speci Nelson,1982);diameter of orbit1.4(1.3-1.7) men 33mm SL stained with alizarin red),Nazca times of snout length;interorbital very narrow.

Ridge(25•‹44'S,86•‹27.5'W)at 370-395 m,October Anterior nostril tubed,posterior one a simple 3,1980;Sigsbee trawl,same collector;USNM pore.Feeble spine along dorsal margin of

(United States National Museum of Natural History, opercle;subopercle pointed posterodorsally into Washington,D.C.)265048,2 specimens 27 and 28 another feeble spine(not evident in some para mm SL,Nazca Ridge(25•‹27'S,85•‹05.5'W)at 330m, types).Opercular membrane enlarged,with October 6,1980,benthic dredge,same collector; serrations along upper margin.Branchiostegal BPBM(Bernice P.Bishop Museum,Honolulu, membranes separated,extending far forward; Hawaii)29194,2 specimens SL 20.5 and 27mm, same data as USNM 265048. (7 branchiostegals in stained paratype).Gill Diagnosis.First dorsal fin low,with 5 or 6 rakers short and broad,1+11(0 to1+10to 13,total1-14in10 paratypes).Teeth small, feeble closely set spines and large jet-black spot on the middle part of membrane.Second villiform in two bands on both jaws.Each side

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B C

Fig.1.Osopsaron karlik,holotype,ZIL 46748,30.5mm SL.A,lateral view(modified from Parin, 1982);B,dorsal view of head and predorsal region;C,ventral view of head and pelvic fin region . of the head of vomer with 3 teeth arranged trans branched in larger paratypes),elements increas versely(3-9teeth in one or two rows in para ing in length from first,fourth soft ray longest. types).Palatine teeth absent. Caudal fin truncate,with 14 rays,8 of them Two dorsal fins with bases well separated. branched. D1V(VI in2paratypes);spines subequal,thin Selected proportional measurements(in per and flexible(damaged in most paratypes),their centage of standard length)of holotype and10 bases contiguous and very slightly offset from paratypes(or 1 paratype 35mm SL when in midline.D2 19(20in1paratype only);all rays dicated by an asterisk):head length35.7(35.2 unbranched.A23(22in1paratype);all except 38.4),head width 16.4(15.018.7),snout length first and last branched.P1 20(19-20),most 7.9(7.6-9.2),postorbital length 17.4(15.2 rays branched.Pelvic fins well separated,in 17.3),length of orbit 10.8(10.714.2),least bony serted much before pectoral fins.P2 I,5,first interorbital width0.7(0.5-0.7),length of upper and last soft rays unbranched(first soft ray also jaw13.8(13.115.2),body depth13.1(9.8-

Table1.Comparison of O.karlik and three species placed in Osopsaron by Nelson(1982).

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14.0),caudal peduncle depth5.0(4.3-5.2),1st acterized by dorsal spines closely set(as in both predorsal length39.0(36.942.5),2nd predorsal Pteropsaron and Osopsaron),by high median length51.5(50.753.6),preanal length48.5 fins and absence of dorsal operculum in the eye (46.050.8),interdorsal length(between last (as in Pteropsaron),and by branched anal fin dorsal spine and first soft ray)10.5(9.412.4), rays(as in Osopsaron).Among other features length of 2nd dorsal fin base 42.7(37.343.2), these specimens differ from descriptions of the length of anal fin base50.8(45.851.7),length two known species of Pteropsaron,P.evolans of dorsal fin spines:1st12.8,2nd13.1,3rd13.8, Jordan et Snyder of Japan and P.heemstrai 4th13.8(11.4*),5th 13.8,longest dorsal soft ray Nelson of Natal(P.neocaledonicus Fourmanoir 13.4(10.0*),longest anal fin ray 9.8(8.0*), et Rivaton,1979 should be excluded from this longest pectoral fin ray 20.0(16.2*),length of genus as well as,probably,from the Hemero coetinae)in having not the fourth but first dorsal pectoral fin 20.6(19.521.4),length of pelvic fin 25.6(25.027.2),interpelvic distance 4.3 spine most elongated(extends near to the end of second dorsal fin)and in less numerous (4.1-5.1). Colour in alcohol:body and fins almost median fin rays(D V,19vs.VI,21-22;A23vs. entirely pale except for large jet-black spot(or 25-27).They also have some minor morpho broad band)on the middle part of first dorsal metric and meristic differences distinguishing fin membrane and a few scattered melanophores them from every species of Osopsaron:O.karlik, on trunk as shown in Fig.1. for example,has more numerous pectoral fin Relationship.The generic placement of O. rays(P119-20vs.usually18,one count of17 karlik is open to discussion.Clearly,the new and one of19recorded in 34 examined fins) species is a member of the percophid subfamily and longer interdorsal distance(9.4-12.4% SL Hemerocoetinae and belongs to that poorly vs.6.5-8.9%). differentiated group of genera which includes Thus,the undescribed Hawaiian species shares Acanthaphritis Giinther,Pteropsaron Jordan et diagnostic characters with both Pteropsaron and Snyder and Osopsaron Jordan et Starks.Most Osopsaron considered in the narrow sense of of all it resembles O.verecundum(Jordan et Nelson(1982).The necessity of revising the Snyder),O.incisum(Gilbert)and O.natalensis generic criteria in the Hemerocoetinae is evident. Nelson assigned by Nelson(1982)to Osopsaron Etymology.The name karlik(meaning"a as having low dorsal and anal fins,branched dwarf"in Russian)is proposed in accordance rays in anal fin and scaled cheeks(two last with the small size of examined specimens. characters were not checked in all species). Grammatically,it should be treated as a noun Therefore the new species is considered here in in apposition. the same genus rather than in Pteropsaron where Acknowledgments it was tentatively placed as P.incisum(?)earlier (Parin,1982). I am indebted to two of my colleagues at the Differences among the four known species P.P.Shirshov Institute of Oceanology,S.D. of Osopsaron are not sharp but permit species Chistikov for collecting the types and G.N. recognition by combination of characters listed Pokhilskaya for drawing the figures.I wish in Table 1.Also,their distributional ranges also to thank Dr.J.E.Randall for the loan of appear to be restricted and widely separated material from BPBM and Dr.T.Uyeno for (0.verecundum,O.incisum and O.natalensis critical reading of the manuscript. are known,correspondingly,only from Japan, Literature cited Hawaii and Natal). Fourmanoir, P. and J. Rivaton. 1979. Poissons de Remarks.Regretably,I had no opportunity la pente recifale externe de Nouvelle-Caledonie to examine personally any species of Osopsaron et des Nouvelles-Hebrides. Cah. IndoPacif., 1 (4): other than O.karlik.All17specimens of 405-443. "incisum"borrowed from the Bernice P.Bishop Gilbert, C. H. 1905. The deep-sea fishes of the Museum in Honolulu(4 lots:BPBM nos.23681, Hawaiian Islands. Bull. U. S. Fish Comm., 23: 23727,24260 and 24871)proved to represent 577-713, pls. 66-101. another undescribed hemerocoetine species char Jordan, D. S. and J. O. Snyder. 1902. A review of

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the trachinoid fishes and their supposed allies Russian with English abstract). found in the waters of Japan.Proc.U.S.Natn. (P.P.Shirshov Institute of Oceanology,Academy of Mus.,24(1263):461-497. Sciences U.S.S.R.,Moscow 117218,U.S.S.R.) Nelson,J.S.1982.Pteropsaron heemstrai and Osopsaron natalensis(Perciformes:Percophidae), Nazca Submarine Ridgeから採集されたホカケトラギ new fish species from South Africa,with com- ス科の1新種Osopsaron karlik ments on Squamicreedia obtusa from Australia Nikolay V.Parin and on the classification of the subfamily Heme- rocoetinae.Spec.Pubi.J.L.B.Smith Inst.Ich- Nazca Submarine Ridgeの水深300～395mから, thyol.,(25):1-11. 11個体のホカケトラギス科の新種Ososaron karlil Parin,N.V.1982.Additions to the list of fishes が採集された。本種は日本のヒメトラギスO.vere- of the Nazca Submarine Ridge and adjacent area. cundum,ハワイのO.incisumおよびナタールのO. In Insufficently studied fishes of the open ocean. natalensisから,鰓紀数,鰭条数,第1背鰭の色彩お Inst.Okeanol.Akad.Nauk SSSR:48-54.(In よび長い頭部などの形質で区別される。

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