NAT. 町ST. B 肌L. SIAM Soc. 54(2): 285-293 ，2006

MAKARARAJA CHINDWINENSIS ，A NEW GENUS AND SPECIES OF FRESHWATER DASYATID PASTINACHINE STINGRAY FROM UPPER MYANMAR

Tyson Tyson R. Robert l-

ABSTRACT

Makararaja Makararaja chindwinensis new genus and species is described from a single mature female female specimen from the Chindwin Ri ver ，Irr awaddy basin ， in northem My 飢 m 釘. De spite 白e round round disc and somewhat slender tail ，i臼 relationships 釘 enot with the whiptailed stingrays of 由巳 subfamily Dぉyatinae ，but wi 白 the flagtailed stingray genus Pastinachus. Makararaja and and Pastinachus (of which Hypolophus is a junior synonym)ωge 出巴 rform the new dasyatid subfamily subfamily Pastinachinae.

Key Key words: Dasyatidae ，Makararaja chindwinensis ，Myanm 訂， new genus ，Pas 血 achinae ，stingx 百y

問 TRODUCTION

Despite Despite hearsay accounts of 企'eshwater cart i1 aginous fishes or elasmobranchs 泊出e Irr awaddy basin and elsewhere wi 血in Myanmar ， no reliably docum 叩ted spec 泊lens have come to light un ti1 the distinctive stingray that is the subject of 出is article. 百le only preserved preserved spec 加len was obtained in the Chindwin Ri ver during fieldwork by the author 泊 collaboration collaboration with the Myanmar Department of Fisheries in April 2003. Whi1 e clearly related related to the marine and e町 yhal 泊 e dasyatid genus Pastinachus Ruppell 1829 (formerly Hypolophus Hypolophus Muller and Henle ，1837) ， it differs markedly from previously described species and and represents a new genus. Local fishermen report it is 合equently caught 泊 the Chindwin River River between Kampti and Tam 印刷and also for some distance downs 回 am from Taman 血i. Th e holotype of 血e new species is deposited in the Zoological Reference Collection (ZR C)， Raffles Museum for Biodiversity Research ，National University of Singapore.

Pastinachinae Pastinachinae new subfamily

Pastinachinae 釘 e whiptailed stingrays or Dasyatidae di 百'ering 企om other members of the the fam i1 y in having the upper jaw very strongly 訂 'cuate and with coηespondingly shaped toothplates. toothplates. Lower jaw anteroposteriorly elongate. 百le teeth are pavement-like. Tail thicker ne 紅 base than in Dasyatinae and with sp 加e in 回目ion relatively far posterior. Ventral cutaneous cutaneous ta i1 fold well developed. Two genera ，Pastinachus ， with P. sephen and several unrecognized unrecognized or undescribed species perhaps including P. sankur or P. fluviatilis (Ham i1 ton 1822) 1822) (R OBERTS ， 1998; LAST EI AL. ，2005) ，加 d Ma 初 raraja new genus ， with a single species. 百le new genus di 釘ers markedly from Pastinachus in having a nearly oval disc

IResearch Associate IResearch ，Smithsonian Tropical Resear 官h Institute; tysonregalecu S@ yahoo.com

285 286 TYSON R. ROBERTS

with with the dorsal surface wi 出 minute dermal denticles versus a “di 叩 lond ・shaped" or 丸紅ongly rhomboidal" disc with the central p紅 t of its dorsal surface with relatively large dermal dermal denticles. τ'h e widely used stingray genus name Hypolophus Muller & Henle 1837 (wi 血 generic type type species R 可a sephen Forsskal 1775) is now recognized as a junior synonym of Pastinachus Pastinachus Ruppell 1829 (w 抽出e same generic type species) (PAXTON ET AL. ， 1989: 43; LAST & COMPAGNO ， 1999: 1482; and ROSENBERGER ， 2001: 615). All of the species 訂 e superficially superficially rather sirnilar ， with a thick ， diamond-shaped or rhomboidal disc; heavy dermal denticulation denticulation in middle of 白e upper surface of the disc; a thick-based tail ， with well developed developed ventral cutaneous membrane; and a sting located relatively far pos 旬riorly on 白e tail tail (Figs. 1-2). Pastinachinae Pastinachinae may be referred to by the common name “flag-tailed stingrays" in reference reference to the conspicuous ven 回 1 cutaneous tail membrane (山 o after the 百聞name for P. P. sephen: pla gaben tong). Note on Raja fluviatilis (Fig. 2) ー-S ometimes placed in Hi mantura ，Raja fluviatilis Hamilton Hamilton 1822 (type locality Ganges) belongs in Pastinachus. If the n釘 ne is available (see ROBERTS ， 1998) it is either ajunior synonym of P. sephen or a valid sp 配 ies of Pastinachus. Raja Raja sankur Har 凶lton 1822 is 白e next available junior synonym of R. fluviatilis (op cit ふ

Makararaja new genus

Type species.-Makararaja chindwinensis new species Formerly Formerly all of 出e species of Pastinachinae could be assigned to a single genus ， Hypolophus or Pastinachus (F igs. 1-2). 官 le new genus described here differs 企om all other other dasyatid genera 担 having a nearly round disc with the dorsal surface with pe 紅 I organs organs and other dermal denticles so minute 白紙 it seems to lack them. It also differs 加 tail tail mo 甲hology. Fl oor of mouth with four pap i1l ae: two 泊 the middle and one to each side (versus (versus five in Pastinachus ， with three 也 the middle of 出emou 血). In other past 泊achines the the tail is exceptionally stout proxin 凶 ly ， and the sting insertion is located ti 紅白 er posteriorly. τ'h e tail has a well-developed v印刷1 cutaneous membrane but its depth is much less 白m in in Pastinachus. 官le s由19 泊se 凶on is relatively far posterior comp 釘 'ed to non-pas 血 achines ， but but not so far posterior as in Pastinachus. Th e base of the tail is more slender 由加担 Pastinachus Pastinachus but not so slender as in Himantura and other dasyat 泊 genera. Pectoral Pectoral fm pterygiophores 105-1 07? versus 111-126 泊 Pastinachus (Peter Last ，pers. comm. 11 Jan 2005). In the shape of 由e jaws and toothplates Makararaja is basically s加担紅白 Pastinachus.

Makararaja chindwinensis new species Figures Figures 3-8

Holotype. ー ZRC 50566 ， 385 mm disc width ， mature female ，Chindwin River about 20 km downstream 仕om Kh amti ， 19 April2003 ，Tyson R. Roberts (血 e new species is well known to fishermen 加出 e stretch of the Chindwin River between Kh amti and Taman 也i. According According to 出e fisherman who caught it 出e holotype is full grown. From the remarks of several several fishermen the species does not get much larger). MAKARARA .l A C /-I IN DW INENS IS，A NEW GENUS AN D SPEC IES OF ST INGRA Y 287

Fi gllr e 1. Pa :、lilla c! III S cr se ph ell (from D AY ，1 875)

Figllr e 2. R旬。 Jl lllliali /i s H amilt on 1822 . Thi s nom in al sp巴cles IS 1巴I" erabl e to Pa slina clllls. It is eith 巴ra Jun l or

sy nonym of P ‘l" eph c lI or a va lid spec i es (fro l11 R O tlERT S. 1998) . Not e d iffere n ces in c1 i sc shap e ancl

ve ntral tail -folcl co mp 山 ecl to P. cf seph ell in F ig. 1 288 288 TY SON R. Ro日ERT S

Fig llr e 3. Makararaja chilldwill ell sis. H ololype，Z R C 50566. 385 111111 fe l11 ale

Figure Figure 4 . Pea rl spin es and d巴nli cl巴S near ce nl er of dor sal slI rf ace of di sc. a-b ，P 乱、 tilla c! III S cI seph ell ，Z R C

50645 ，3 15 111m ma le; c-d Makararaja chilld ll' ellsis ，Z R C 50566 ，50 566 ，385 111111 f巴，l11 al e.(a and c al sa l11 e sca le，b= 53% 0 1" d) MAKARAR A .l A C HI N DW INENS IS，A N EW GENUS AND SPEC IES OF ST INGRA Y 28 9

a

FigUl 巴 5. Maka rar aja chindwin ellS is. Jaw t巴巴 th .a，u pper j aw; b，lowe rj aw

Fig ur e 6. Makararaja chilldw ill ell sis . Rad iograp h of jaw sw it h m out h s hut 290 T YSON R. R OBERTS

Figure 7. Makararaja chindwinensis. Porr ion of ta il with stings. a, lateral vie w; b, dorsal view.

Fi gure 8. Makararaja chindwinensis. Spiral va lve. MA ιほ A丸4J AC Hl NDWINENSIS ，A NEW GENUS AND SPECmS OF ST 町 GRAY 291

Comparative material of Pastinachus.-Pastinachus cf sephen ，ZRC 50645 ， 3: 297-315 mm ，Singapore ， Jurong Fish Port ， K. L Iij1 and M. Manj 吋i，Feb 1997. Diagnosis.-A small species of freshwater dasyatid. Maximum disc size reportedly about about 500 mm and maximum weight 3-4 kg. Disc with slightly 住iangul 訂 shape ， but mo 詑 nearly nearly round than in any known species of Southeast Asian freshwater dasyatid species (Fig. (Fig. 3) ， and very distinct 企'O m the tri 個別l訂 or diamond-shaped disc of Pastinachus (Figs. 1-2). 1-2). Pearl buttons and other dermal denticles of dorsal disc surface minute ，f; 紅 smaller than than those of Pastinachus (Fig. 4). Pectoral fm radial pterygiophores (propterygial + mesopterygial mesopterygial + metapterygial=total) 51 + 8 + 46 -4 8? = 105-10 7? Pelvic fm pterygiophores 2ι27. Discrete vertebral centra about 130. Tail with a long but relatively low-ly 同 ventral fin fin fold (F ig. 7). Sting very slender ，stiletto-like ， with very 血le point (Fig. 7). Sting with 59 barbs on left side ，70 on right side. Spiral valve tums 16- 17 (Fig. 8) (versus 20 泊 some Pastinachus). Pastinachus). Morphometric characters.-See Table 1.

Table Table 1. Ma 初 raja chindwinensis measurements of holotype in mm/% of disc width Di sc width 385 mm Disc Disc length 2 390 /1 0 Maximum width across pelvic fins 199/5 1. 6 Extemal Extemal width betw 田 n pelvic f泊 origins 99/25.7 Le ast 泊t釘 spiracular width 68.5/17.8 Extemal Extemal eye bulge 25.0/6 .4 Snout Snout leng 出3 78/20.3 Spiracle Spiracle leng 出 29.5n.7 M 蹴加um intemarial width 48/12 .4 Wid 血 of mouth opening at lower jaw 37ρ.6 Width of first gill slit 12.5β2 Wid 白 of fi 加 1 gill slit 8/2 .1 Least Least distances between successive gill slits: First First and second 84/2 1. 8 Second and 白ird 077/20 Thi rd and fourth 64/16.6 Fourth Fourth and 白血1 54/14.0 Exposed nos 凶 llength 12.6/3 .3 Pr e-sting tail length 312/8 1. 0 First First sting length 113/29 .4 First First sting maximum width 3.8/.98 Second sting length 25/6 .4 Total Total tail length 575/149 .4 Ventral Ventral cutaneous tail membrane len 併1 265/68.8 Ventral Ventral cut 加 eous tail membrane depth 8.2/2.1

2S 位置 ight line me 鎚 urement 針。 m snout tip 10 distal m 訂 gin of pelvic fins 3S佐aight line m 切 surement 仕om snout tip to front of eye 292 TYSON R. ROBERTS

Coloration.-Dorsal Coloration.-Dorsal surface pale grey or tan; ven 回 1 disc surface white (F ig. 3). Tail with with distinct banding continued onto ven 回 1 cutaneous membrane (Fig. 7).

Gu t.ー百 le al 加 entary tract was excised about one inch below the oroph 紅戸1geal cavity cavity and an inch above 出e cloaca or ven t. It was 白en sliced open for its entire leng 白 by as 泊gle mid-ventral cu t.百 le postph 紅 yngeal gut ， with a to ta1 length about 340 mm ， comprises comprises six morphologically distinct sections. Except for the spiral valves ， these sections 紅 e continuous ，i. e. ， not separated by valves or marked cons 凶ctions ， so that the exact limits

紅 e not well defmed. 百le esophagus ， about 50 mm long ， has ι8 佐'ansverse ridges. Th ese grade 泊to an expanded expanded stomach ， about 60 mm long ， with 19-20 1紅 ge ，出 ick ，and rugose folds. 百le stomach stomach is followed by a nearly featureless smooth-walled section of gut 85 mm 泊 leng 白. 百le thickened anterior half of 血is section has a single thick fold ， 35 mm long and up to 10 10 mm wide ， with lateral margins indented 企om main wal l. A very thin-walled featureless section section extends posterior to the fold for 35 mm ， to the beginning of the spiral valve. 四 e thickened spiral valve ， with 16- 17ωms ，is 110 mm long. 百le frrst spiral valve tum is extremely elongate ，its length 40 mm 仕om its orig 泊 to 血e origin of the second ωm. Successive Successive ωms ru:芭 progressively smaller. Th e posterior-most p紅 t of 出e gut ， about 60 mm long ， has almost featureless 血in walls.

Etymology.-Makararaja (gender feminine) is 企om 出e Sanskrit ，makara ，originally meaning crocodile ， but also 血e term for the cosmological arches or gateways of 回ndu temples temples shaped like the open jaws of a crocodile ， in allusion to the shape of the jaws of pastinachine pastinachine stingrays including this new genus; and raja ，Latin ， for a skate or ray fish; chindwinensis chindwinensis for the Chindwin Ri ver ， where the fish lives.

CONCLUSION

Until Until now it was generally considered 出at Pastinachus were essentially marine fishes ， and 白紙血eir occurrence in freshwater was a matter of adult fish 泊血 e tidal or lower p釘 t of of rivers occasionally expa 凶 ated 企om marine populations. 官le pr 回l ence of af 也shwater pastinachine 泊血e upper Irr awaddy basin some 85ι950 km inland was totally unexpected.

Perhaps Perhaps there 釘 'e also species of Pastinachus 白紙 live only in 合esh water. For a summ 釘 y of of riverine and 企eshwater records at 凶buted to P. sephen see COMPAGNO & COOK (1 995: 78). 78). A recent 合eshwater riverine record of Pastinachus (as Hypolohpus sp) is 合om the Bar ru:n River basin 泊 Sarawak (N y 釧百Ef AL. ， 2006: 106).

ACKNOWLEDG 恥ffiNTS

百le author's fieldwork on the Chindwin River and elsewhere 泊 Myanm 訂 is being done done in cooperation with the Myanm 訂 Dep ru:加， ent of Fisheries. U Hl aW 加， Deputy Director-General ， has been p制 icularly helpfu l. Funding for the author's recent fieldwork in in Myanmar has been provided by gran 飽食om 出e Smithsonian Tropical Research In stitute and the Chester Zoological Garden and North of England Zo ological Society. 百lis paper was written 泊 the Center for Conservation Biology at Mahidol University ， Salaya c釘 npus ， MA κARARAJA CHINDWINENSIS ，A NEW GENUS AND SPECIES OF ST 町 GRAY 293

百lailand ， and in the Raffles Museum for Biodiversity Research at the National University of of Singapore. Tan Heok Hui ，M 訂 tyn Low Ern Yee ， and Kelvin P. K. Li m helped with photography. photography.

REFERENCES

COMPAGNO ， L. J. V. 1999. Chec k1 ist of living elasmobranchs.ln: Hamlett ，W. C. (ed.) ，Sharks ，Skates ，and Rays: the the Biology o[ Elasmobranch Fishes. Johns Hopkins Univ. ，Baltirnore & London. COMPAGNO ， L. J. V. ，AND S. F. COOK. 1995. 百 le exploitation and conservation of freshwater elasmobranchs: status status of taxa and prospects for the 釦ture. Pages 62-90 in M. 1. Oetinger and G. D. Zorzi (eds.) ，The Biology Biology o[ Freshwater Elasmobranchs. Journal o[ Aquariculture and Aq 凶 tic Sciences 7: 1-162. DAY ， F. 1875. The Freshwater Fishes o[ lndia ， Being a Natural History o[the Fishes Known to lnhabit the Seas and Fresh Waters o[ lndia ，Burma ，and Ceylon. London ，P制 1: 1-168 ，pls. 1-4 0. LAST ， P. R. ，M. MANIAJI ，AND G. K. YEARSLEY. 2005. Pastinachus solocirostris sp. nov. ，a new species of stingray (Elasmobranchii: (Elasmobranchii: Myliobatiformes) 仕om 出.e In do ・Malay archipelago. Zoo 低 xa 1040: 1-16. LAST ， P. R. ，AND L. J. V. COMPAGNO. 1999. Several family accounts of batoid fishes. In: Carpenter and Niem ， Species Species Identification Guide for Fisheries Pu rposes. Th e Li ving Marine Resources of the Westem Central Pacific. Pacific. Batoid fishes ，chimeras and bony fishes p釘 t 1 (Elopidae to Li nophrynidae). FAO ，Rome 3: iii-vi + 1398-2068 ， I-IV. NYANTI ，L. ， A. K. SAYOK ，AND E. EFRANSJAH. 2006. Fish fauna of Lo agan Bunut National P訂 k，S紅 awak. Pages 102-109 102-109 in A. A. Tuen ， A. Y. Sayok ， A. N. Toh ， and G. T. Noweg (eds.) Scientific Journey through Borneo: Borneo: Loagan Bunu t. Universiti Malaysia Sarawak. PAXTON ，J. R.， D. F. HOESE G. R. ALL 凹 AND J. E. HANLEY. 1989. Pisces. Pe 回 myzontidae to Carangidae. Zoological Zoological Catalogue o[ Australia ，Volume 7. Aus 甘alian Govemment Pu blishing Service ，Canberra. i-xii + 1-6 65 pp. ROBERTS ， T. R. 1998. Francis Hamilton and the freshwater stingrays described in his Gangetic fishes (1822). Arch. Arch. Nat. Hist. (London) 25(2): 267-280. ROSENBERGER ， L. J. 200 1. Phylogenetic relationships within the stingray genus Dasyatis (Chondrichthyes: Dasyatidae). Dasyatidae). Copeia 2001 (no. 3): 615 -6 27.