Plotosus Fisadoha, A New Species Of Marine Catfish (Teleostei : Siluriformes : Plotosidae) From Madagascar

6 Pages·2002·2.2 MB·English

by  H H Ng

PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
115(3):564-569. 2002.
Plotosusfisadoha, a new species of marine catfish
(Teleostei: Siluriformes: Plotosidae) from Madagascar
Heok Hee Ng and John S. Sparks
(HHN & JSS) Fish Division, Museum of Zoology, University of Michigan, 1109 Geddes Avenue,
Michigan 48109-1079, U.S.A.
—
Abstract. A new species ofplotosid catfish, Plotosusfisadoha, is described
from the coastal waters of southeastern Madagascar. Plotosusfisadoha can be
distinguished from congeners by the following unique combination of char-
acters: head length 23.7-23.9 %SL; head width 13.7-15.2 %SL; head depth
11.5-11.8 %SL; body depth at dorsal-fin origin 13.1-13.3 %SL; pectoral-fin
length 14.9-15.0 %SL; pelvic-fin length 9.7-9.8 %SL; snout length 39.0-39.2
%HL; interorbital distance 32.9-33.4 %HL; eye diameter 13.1-14.3 %HL; na-
sal barbel length 40.7-44.0 %HL; maxillary barbel length 47.0-52.3 %HL;
outer mandibular barbel length 47.0-47.7 %HL; 58-59 vertebrae; 10 caudal-
fin rays; 164-171 total confluent median fin rays; and uniform brown colora-
tion.
The family Plotosidae (eel-tailed catfish- lor 1982; Ferraris in Randall & Lim 2000),
es) is a small assemblage of marine and viz. Plotosus abbreviatus Boulenger 1895,
freshwater catfishes found throughout the P. canius Hamilton 1822, P. limbatus Va-
& &
Indo-Pacific. Allen Feinberg (1998) rec- lenciennes, in Cuvier Valenciennes 1840,
ognized 31 species in 10 genera. The sys- P. lineatus (Thunberg 1787), P. nkunga
tematics of Plotosidae are poorly under- Gomon & Taylor 1982, and P. papuensis
stood, and there have been few revisionary Weber 1910.
studies (e.g., Gomon & Taylor 1982, Allen While conducting a survey of the fresh
1998), none encompassing the entire as- and brackish water fishes of Madagascar,
semblage. Plotosus is primarily marine and the second author obtained specimens of
distributed throughout the Indo-Pacific. Plotosus from the southeastern coast of the
Plotosus is distinguished from other ploto- island that are morphologically distinct
sid genera by the following unique combi- from any previously described species. The
nation of characters (Gomon & Taylor description of this material forms the basis
1982): a dendritic organ posterior to the of this contribution.
anus, gill membranes separate and free
from the isthmus, four pairs ofbarbels, lips Methods
without lobes or barbel-like extensions, tu-
bular anterior nostril at or above the edge Measurements were made with dial cal-
of the upper lip, and teeth on the premax- ipers and data recorded to 0.1 mm. Counts
illa. Ofthe characters described above, only and measurements were made on the left
the presence of a dendritic organ is a syn- side of the specimens whenever possible.
apomorphy of some plotosids, although it Vertebral and median fin-ray counts were
is not unique to Plotosus (present also in taken from radiographs. In tables and text,
Paraplotosus, Cnidogtanis, Euristhiuus and subunits of the head are presented as pro-
Otoplotosus). Six species of Plotosus are portions of head length (%HL). whereas
currently considered valid (Gomon & Tay- head length and measurements of body
VOLUME 115, NUMBER 3 565
UMMZ mm
Fig. 1. Plotosusfisadoha, holotype, 232679, 191.8 SL, Madagascar: southeastern coast: Fian-
arantsoa Province: Farafangana market.
parts are given as proportions of standard and a body lacking pale horizontal stripes
length (%SL). (vs. stripes pres—ent).
Measurements and terminologies follow Description. Morphometric and meris-
those of Gomon & Taylor (1982), except tic data presented in Table 1. Body laterally
for vertebral counts, which include the compressed and somewhat anguilliform, ta-
complex anterior vertebra and count the pering posteriorly. Anus and urogenital
first free vertebra as the sixth. Institutional openings located at vertical through mid-
acronyms follow Leviton et al. (1985). point of appressed pelvic fin. Dendritic or-
gan located posterior to anus. Skin smooth.
Plotosusfisadoha, new species Lateral line complete and midlateral in po-
Fig. 1 sition.
Head depressed and broad. Snout margin
Holotype.—\JMMZ 235269, 191.8 mm rounded viewed from above. Upper lip
SL; Madagascar: southeastern coast Fian- fleshy, plicate and papillose. Gill openings
arantsoa Province; Farafangana market; ac- wide, extending from posttemporal region
quired from fisherpersons; J. S. Sparks, K. to beyond isthmus (i.e., to a vertical
J. Riseng, & P. N. Reinthal, 18 Jun 1994. through anterior orbital margin). Gill mem-
Paratypes.—\5MMX 238723, 1 ex., branes free from isthmus and each other.
mm
180.4 SL—; data as for holotype. Four pairs of barbels, each barbel some-
Diagnosis. Plotosusfisadoha can be di- what broadened and flattened. Maxillary
agnosed from congeners except for P. ab- barbel extending posteriorly to preopercle
breviatus and P. lineatus in having fewer when appressed. Nasal barbel extending to
total rays in confluent median fins (139- posterior margin of orbit. Origin of inner
200 vs. 202-281) and vertebrae (54-63 vs. mandibular barbel near to midline; barbel
72—85). Plotosus fisadoha differs from P. thicker and longer than nasal barbel and ex-
abbreviatus in having a longer pelvic fin tending to vertical through posterior orbital
(9.7-9.8 %SL vs. <8.6), deeper body margin. Outer mandibular barbel originat-
(13.1-13.3 %SL vs. <12.3), larger eye ing posterolateral to inner mandibular bar-
%HL
(13.1-14.3 vs. 8.1) and shorter nasal bel, extending to level of preopercle.
%HL
barbels (40.7-44.0 vs. 69.6), and Eye ovoid, horizontal axis longest; locat-
from P. lineatus in having a more slender ed entirely in dorsal half of head.
head and body (head depth 11.5-11.8 %SL Mouth subterminal. Oral teeth small,
vs. 12.0-13.0; body depth at dorsal-fin or- peg-like or molariform, in irregularrows on
igin 13.1-13.3 %SL vs. 13.4-15.2), a all tooth-bearing surfaces. Premaxillary
%HL
smaller eye (13.1-14.3 vs. 15.1-18.4) tooth band rounded, of equal width
566 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
—
Table 1. Morphometric and meristic data for Plotosusfisadoha.
UMMZ235269 UMMZ238723
(holotype) (paratype)
Morphometries
SL 191.8 180.4
%SL
In
Head length 23.9 23.7
Head width 13.7 15.2
Head depth 11.5 11.8
Predorsal distance 28.4 28.8
Preanal length 45.6 42.8
Prepelvic length 37.7 37.3
Prepectoral length 22.5 21.0
Body depth at dorsal-fin origin 13.3 13.1
Pectoral-fin length 15.0 14.9
Length ofdorsal-fin base 5.8 4.9
Pelvic-fin length 9.7 9.8
Caudal-fin length 7.8 8.3
%HL
In
Snout length 39.2 39.0
Interorbital distance 32.9 33.4
Eye diameter 13.1 14.3
Nasal barbel length 44.0 40.7
Maxillary barbel length 52.3 47.0
Inner mandibular barbel length 41.4 43.0
Outer mandibularbarbel length 47.7 47.0
Meristics
Dorsal fin rays 1,4 1,4
Pectoral fin rays 1,12 Lll
Pelvic fin rays iii,8 iii,7
Procurrent caudal rays in dorsal lobe 89 89
Caudal fin rays 10 10
Anal fin rays 65 72
Branchiostegal rays 11 11
Gill rakers on first gill arch 6+16 6+16
Vertebrae -h 43 = 59 17 + 41 = 58
throughout. Dentary tooth band much nar- Anal and caudal fins confluent, forming a
rower than premaxillary tooth band at sym- continuous median fin along posterior two
physis, tapering laterally. Vomerine tooth thirds of body dorsally, posterior half of
patch a median triangle ofmolariform teeth. body ventrally. Pelvic-fin origin at vertical
Dorsal fin located above anterior third of through anterior end of upper procurrent
body; origin nearer tip of snout than caudal caudal-fin rays. Pelvic-fin margin slightly
flexure. Dorsal-fin margin convex, first fin convex, tip of appressed fin reaching anal-
ray longer than others. Dorsal-fin spine fin origin. Pectoral fin with stout spine (bro-
straight and robust (broken in both speci- ken off in both specimens). Pectoral-fin
mens). Anal fin with long base and extend- margin straight anteriorly, convex posteri-
ing along posterior half ofbody. Caudal fin orly. —
lanceolate, with greatly enlarged upper pro- Coloration in presen'otive. Dorsal and
current rays forming a second dorsal fin ex- lateral surfaces of head and body uniform
tending along posterior two thirds of body. brown; ventral surfaces of head, breast and
VOLUME 115, NUMBER 3 567
USNM
belly lighter brown, with scattered mela- Plotosus nkunga: 226490, 3 ex.,
mm
nophores. Barbels brown, gradually fading paratypes, 432-489 SL; South Africa:
in color distally. Dorsal and confluent anal eastern Cape, Kasonga.
+ caudal fins hyaline, with dark brown dis- Plotosus papuensis: USNM 217106,
tal margin. Pectoral and pelvic fins hyaline, 30.7-146.5 mm SL; Papua New Guinea:
with sporadically distributed small, dark- mainstream of Palmer and lower end of
brown spots. — small tributary about 1 km up the Palmer
Distribution. Known only from the from Thompson junction (mouth of Wai
coastal waters off the southeastern coast of Mungi), 65 km NE of Kiunga, 930 km up-
Madagascar, Fianarantsoa Province, near river from Toro pass (6°46'48"S 141°
town of Farafangana (22°49'S, 47°49'E). 36'36"E).
There are no coral reefs in this region of Additional data of the last five species
Madagascar, and the new species likely in- listed above obtained from Gomon & Tay-
habits sandy and muddy coastal lagoons lor (1982). —
and estuaries, as opposed to P. lineatus Remarks. Plotosus fisadoha and P. li-
which inhabits coral reefs. It is likely that neatus are the only species of Plotosus
with more intensive survey ofMadagascar's known from Madagascar to date (see Sau-
nearshore marine fauna additional collec- vage 1891, Pellegrin 1933, Kiener 1963,
&
tion localities—will be discovered. Bauchot Bianchi 1984).
Etymology. From a Malagasy contrac- Plotosus fisadoha differs from all con-
tion of the words fisaka, meaning flat and geners except P. lineatus (and possibly P.
loha, meaning head. In reference to the abbreviatus) in having fewer total rays in
broad, flattened head of this species, espe- confluent median fins and vertebrae (Table
cially when compared with the sympatric P. 2). It further differs from P. canius in hav-
lineatus. An unlatinized specific epithet ing longer pectoral and pelvic fins, barbels
used as a noun in appositio—n. and snout, a longer and deeper head, and a
Comparative material. Plotosus ab- larger eye (Table 2); from P. limbatus in
BMNH
breviatus: 1894.8.3.35, 1 ex., ho- having longer pelvic fins, head and barbels
mm
lotype, 382 SL; Borneo: Sarawak, (Table 2); from P. nkunga in having a lon-
mouth of Baram River. ger, narrower head and wider interorbital
UMMZ
Plotosus canius: 225087, 1 ex., distance (Table 2); and from P. papuensis
mm
156.0 SL; Thailand: Cholburi, Gulf of in having longer pelvic and pectoral fins,
UMMZ
Thailand, shore near Ban Si Racha. snout, barbels, a narrower and more slender
mm
227490, 1 ex., 228.0 SL; Vietnam: Ba head, more slender body, wider interorbital
Xuyen province, Giao, 3 km S of Truong distance and larger eye (Table 2).
UMMZ
Binh at mouth of Bassac. 234299, Plotosus fisadoha resembles P. lineatus
mm
1 ex., 211.0 SL; Thailand: market at most closely in the number of total rays in
Chantaburi. confluent median fins and vertebrae. How-
USNM
Plotosus limbatus: 219576, 4 ex., ever, it can be easily distinguished from P.
mm
343-366 SL; Sri Lanka: Kakaithivu lineatus in having a more slender head and
fish landing, about 3 miles S of Vadduk- body, and a smaller eye (Table 2). The color
kodai. patterns of P. fisadoha and P. lineatus also
UMMZ
Plotosus lineatus: 185455, 24 differ substantially. The former species is
mm
ex., 78.8-165.0 SL; Madagascar: Tu- uniform brown in coloration and lacks pale
USNM mm
lear. 350021, 24 ex., 28.6-36.9 horizontal stripes on the body, whereas the
W
SL; Mauritius: coast, Bale de la Petite latter species usually possesses two or three
Riviere, around and off rocks at N end of pale horizontal stripes on the dorsal and lat-
public beach at Albion, just S ofPointe Pe- eral surfaces of the body, with two of the
tite Riviere. stripes extending to the head.
'
568 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
Boulenger (1895) distinguished P. ab-
^l/^ O^ ^r—<-ic>v^rd)^-rsto-oomor>-mm—^vmoo—*t< ^o ro breviatus from congeners on the basis of
r-; rO tN VDI y-H fewer caudal-fin rays (10 vs. 18). Exami-
00 iri 00 ON nation of a radiograph of the holotype
shows that the caudal region was damaged
and subsequently healed, as evidenced by
<Nvdoirn^~:o6>or<-ir--r^"moo the lack of both hypurals and epurals and
the asymmetric nature of the regenerated
oIqr-I;00Ir<I-)—I'OINtINtIN-I^—I;0I0{1NrMI(NI
Ou-i -"-r- caudal region. Such damage and regenera-
tion is often seen in catfishes with anguil-
liform bodies (and most notably in Clarias;
t^OOCN^OONrn-^rnoo'^Q Lim & Ng 1999). Caudal region deforma-
tion in the only known specimen of P. ab-
\tINq'rIr~^;cI NprI^oprIroooIdri-1r;)0^I>—nI<^^oI\cdoIr^od[I 2o'In'^^I breviatus makes comparison to congeners a
little more difficult. Morphometric ratios
based on %SL cannot be reliably estab-
O(_NN^C*T„; „np-i^-V^^DtoO^nO'*—imr>^r(n^'IvOT-)iN^cOi vvrsOIO•'(I<-*NIm^r.^00 alrieshleidkealnydintfhleatveadlu(ie.se.,prSeLseonftetdheindeTfaobrlmeed2
Oi 00I nI ONi [^I "I *1 t^I 00I. OJN. \0 ON O r^ specimen is less than it would be ifundam-
00 ro
aged). Nevertheless, Plotosus fisadoha is
still easily distinguished from P. abbrevia-
tus in having a longer pelvic fin, deeper
r—-;< CirNi ro-; CrNnj >—o>' ^t-N-'O"cIT<Pt^dmti«-;oOCoNNJodo"i*rr-(iN-o(„oNiooo body, larger eye and shorter nasal barbels
r^oI idnI r--:I ^IioI mrI NI|'I*^I "iI >CNIlooI (TaTbhlee 2M)a.lagasy nearshore marine fauna is
extremely poorly studied and desperately in
need of survey. To date, nearshore marine
vi(VNonrv—V-D^O——VN-Hr—V-iiri—V^roi\o^o/iNOmin—O —o6oNNNOOiNn/Drii(nnNr>^-niOAnN tcoelrleedctlioocnasliatrieesk,nopawrntifcourlaornllyy caolfleewctsicoants-
made by Bardach and Mauge in the late
1960's from the region of Tulear in south-
Or(Nnn (irNi —00 CmO piri 00 COcMnN CC*OO 2C;O p CiCNnO rr^- iwnetsetnesrinfieMdadsaugravsecyaref.foIrttsisoflitkheilsyftahuanta,wiatdh-
11 rn-S ^in1 rn!1 J^n1 ON1 iOCON1 OCNO11 CO1 d p1 ndietwionsapleclioecsa.lities will be discovered for the
Acknowledgments
C£/2 £ We thank James Maclaine (BMNH).
C 3 ^ t/3 Douglas Nelson (UMMZ) and Susan Jewett
[5) X c 2 (USNM) for permission to examine mate-
CJ/5 0J0 a^«ooc 0^sJ^MC0z 0£J0 £ £JI2uc ^^ £IJ6c0j^^Wc:^)XXJruaI)J3 cIEccccDa riLminuoagnludstubhneedrreepgrvh,iotetChwoeaegirrrroalcfpeaohrr.eBcaWarlniedtdwiaciDarnlae,lvygiradrantedBevfaiaueylnwiftaoonnrgJotontahyhk-ne-
C •'i5 •Q1a). EIcC IccC ^_cu '"'B3B CE3 •e _>2. E 1co3) X>) tmaatneudscbryipBt.. ACnoldlreicatmianhgajefafoarntsd wtheereMIfaCciEliT-
iX ^ a1) ao co5i I 0Oc30 uC t<SU^ 'k o(3U 1t52 fB2 E(Innvsitirtountmeenfotrs,thMeaCdoangsaesrcvaart)iosntafoff, Tarnodpicwael
VOLUME 115, NUMBER 3 569
are grateful for their support. Collection dix-septieme. SiluroTdes. Pitois, Paris, 540 pp.
permits were obtained from the Direction + pis. 421-455.
des Eaux et Forets and the Association Na- Gomon,anJ.eRw.,sp&ecWie.sRo.fTcaaytlfiosrh.f1r9o8m2.SPoluotthoAsfursicnak,unwgiat,h
tional pour la Gestion des Aires Protegees a redescription of Plotosus limbatus Valenci-
(ANGAP), Madagascar. Field work was ennes and a key to the—species ofPlotosus (Sil-
funded by grants from the National Science uriformes: Plotosidae). J. L. B. SmithInstitute
ofIchthyology Special Publication 22:1-16.
Foundation (DEB-9300996), and the Unit- Hamilton, F. 1822. An account of the fishes found in
ed States Agency for International Devel- the river Ganges and its branches. Archibald
opment (University Development Linkage Constable & Company, Edinburgh, 405 pp. -I-
Program, USAID Cooperative Agreement, pls. 1-39.
PCE-5063-A-00-3035-00) to P Reinthal. Kiener, A. 1963. —Poissons, peche et pisciculture a
Madagascar. Publication du Centre Technique
This study has been supported by the Rack- ForestierTropical 24:1-244, pis. 1-160.
ham School ofGraduate Studies ofthe Uni- Leviton, A. E., R. H. Gibbs, Jr., E. Heal, & C. E.
versity of Michigan. Dawson. 1985. Standards in herpetology and
ichthyology: Part I. Standard symbolic codes
for institutional resource—collections in herpe-
Literature Cited tology and ichthyology. Copeia 1985:802-
832.
Allen, G. R. 1998. A review ofthe marine catfish ge- Lim, K. K. R, & H. H. Ng. 1999. Clarias batu. a new
nus Paraplotosus (Plotosidae) with the descrip- speciesofcatfish (Teleostei: Clarii—dae)fromPu-
tion o—fa new species from north-western Aus- lau Tioman, PeninsularMalaysia. The Raffles
tralia. The Raffles Bulletin of Zoology 46: Bulletin ofZoology, Supplement 6:157-167.
123-124. Pellegrin, J. 1933. Les poissons des eaux douces
n,e&w gMe.nuNs.aFnedinfboeurrg.ne1w99s8p.ecDieesscroifptfiroensshwoaftear dSeeycMhaedlalgeas,scarMaestcadreesigtnieess)v.o—isiMneemso(iCroemsoredse,
cJaotufrinsahlesof(PIlcohttohsyiodlaoeg)yfarnodmAqAuuasttriacliBai.o—loAgqyua3,: RandalltI,h'eAJ.cfaiEsd.h,eems&ioefKM.tahelKg.SaocRuhteLhiCm1h4.:i1n2-a0202S02e.a,.AP—isc.ThheIec-kIIlRIia.sftfleosf
9-18.
Bauchot, M.-L., & G. Bianchi. 1984. Guide des poi- SauvageB,ullHe.tiEn.of18Z9o1o.loHgiys,toiSrueppplheymseinqute,8:n5a6t9u—r6el6l7e.et
sons commerciaux de Madagascar(especesma- politique de Madagascar. Volume XVI. Histoire
rinesetd'eauxsaumatres). FAO,Rome, 135pp. naturelle des poissons. Imprimerie Nationale,
+ pis. 1-16. Paris, 1-543, Pis. 1-50.
Boulenger, G. A. 1895. Descriptions oftwo n—ew fishes Thunberg, C. P. 1787. Museum naturaliumAcademiae
obtained by Mr. C. Hose in Sarawak. Annals Upsaliensis. Partem primam. Doctoral disserta-
and Magazine ofNatural History (Series 6) 15: tion, Uppsala Academy, 32 pp.
Cuvier,2G4.7,.&A. Valenciennes. 1840.Histoirenaturelle Weber,NMe.u-1G9u1i0n.eaN.e—ueNoFitsecshefraoumstNhieedLeeryldaenndiMscuhsSeiuidm-
des poissons. Tome quinzieme. Suite du livre 32:225-240.