Macrocephenchelys brachialis Fowler, 1934

Lin, James, Shao, Kwang-Tsao & Smith, David G., 2018, The eel genus Macrocephenchelys (Anguilliformes: Congridae) in Taiwan, with description of a new species, Zootaxa 4454 (1), pp. 186-199 : 188-192

Macrocephenchelys brachialis Fowler, 1934

FIg. 2 , 3A ; TABLe 1

Macrocephenchelys brachialis FoWler, 1934:277 , Fig. 36. (type locality: Makassar Strait, betWeen Borneo and SulaWesi, Indonesia, Albatross station 5667, 2°56'00"S, 118°47'30"E, depth 367 fathoms [671 m]). Robins & Robins, 1971:128 (redescription and osteology); Karrer, 1983:48 (specimen from Western Indian Ocean). Ho et al., 2015:148 (TaiWan).

Material examined (93 SPeCIMeNS, 155–765 MM TL): Holotype: USNM 92347 (1, 490), MACASSAR STRAIT, 2°56’S, 118°47’30”E, 671 M, 29 DeC. 1909 . Paratype: USNM 93294, (1, 440), SIPADAN I., BORNeO, 4°06’50”N, 118°47’20”E, 635 M, 28 SeP. 1909. Non-types : Daxi, Yilan, northeastern Taiwan: ASIZP 59924 (1, 306), 200–400 M, 20 MAR. 1998 ; ASIZP 60165 (5, 282–422), 200–400 M, 5 OCT. 1997; ASIZP 62538 (1, 472), 308–310 M, 28 MAR. 2003; ASIZP 62539 (1, 457), SAMe; ASIZP 63088 (1, 462), 210–340 M, 2 APR. 2004; ASIZP 63090 (10, 306–495), 350–650 M, 24 APR. 2004; ASIZP 63135 (1, 632), 350–650 M, 24 APR. 2004; ASIZP 63252 (6, 315–428), 21 MAR. 2004; ASIZP 70151 (3, 269–475), 27 MAR. 2004; ASIZP UNCAT. 2009-9-12 (2, 204–207), TAIWAN, NO fURTHeR DATA; CAS 216685 (2, 380–578), 19 JUL. 2001 ; NMMB-P20807 (1, 765 MM TL), 20 JUL. 2012; TOU-AE 6687 (1, gRAVID feMALe, 561 MM TL), 21 NOV. 2012; TOU-AE 6735 (1, gRAVID feMALe, 530), 10 JAN. 2012; TOU-AE 6736 (1, 396), 10 JAN. 2012; TOU-AE 6737 (1, 385), 10 JAN. 2012; TOU-AE 6743 (1, 369), 26 SeP. 2011; TOU-AE 6744 (1, 387), 26 SeP. 2011; TOU-AE 6745 (1, MATURe feMALe, 498), 26 SeP. 2011; TOU-AE 6746 (1, MATURe feMALe, 560), 26 SeP. 2011; TOU-AE 6747 (1, MALe, 330), 26 SeP. 2011; TOU-AE 7030 (1, MATURe feMALe, 426), 9 MAY 2013; USNM 377316 (30, 216–510), 27 MAR. 2004; USNM 391645 (2, 396–415), 8 DeC. 2006. Donggang , Pingtung, southwestern Taiwan: ASIZP 62315 (4, 213–254), 300 M, 1 MAR. 2001 ; USNM 399864 (1, 208), 10 NOV. 2009; USNM 401078 (2, 187–247), 14 NOV 2009. Dongsha Island, South China Sea: ASIZP 60166 (1, 512), 15 MAY 1993 . Taiwan (no further data): USNM 399949 (1, 262), 2009 ; USNM 399950 (3, 155–201), 2009; USNM 402415 (1, 201), 2009; USNM 404319 (1, 170+), 2009. Vanuatu : MNHN 2014-0935 (1, 210), 14°55’48”S, 166°51’46.8”E, DePTH 930–1012 M, 13 OCT. 2006 .

Diagnosis. Macrocephenchelys brachialis IS DISTINgUISHeD fROM THe OTHeR SPeCIeS BY THe fOLLOWINg CHARACTeRS: BODY MORe eLONgATe (DA 2.2–5.9 %TL), MORe DeLICATe AND fLexIBLe; HeAD SHORTeR (7.1–9.5 %TL, 25.6–36.2 %PAL, 1.8–2.8 TIMeS IN TRUNK); DORSAL-fIN ORIgIN WeLL BeHIND TIP Of PeCTORAL fIN; VeRTeBRAe MORe NUMeROUS (173–183); ST PORe PReSeNT; fLeSHY PAPILLAe PReSeNT ON LOWeR jAW BUT NOT DORSALLY ON HeAD; SeNSORY PITS ON VeNTRAL SURfACe Of HeAD AND ANTeRIOR BODY ABSeNT.

Description. MeASUReMeNTS IN %TL: PAL 24.8–31.0 TAIL 69.8–74.9, TR 16.1–22.6, PDL 14.9–17.9, HL 7.1–9.5, DA 2.2–5.9. IN % PAL: TR 63.4–80, PDL 55.4–64.8, HL 25.6–36.2. IN % HL: S 11.2 –20.5, E 10.0 –18.7, IOW 6.9–18.4, UJ 16.0–21.9, LJ 10.4–15.2, GO 3.9–6.7, IB 22.9–46.8, PL 42.4–74.5. POReS: PDLL 16–18, PALL 33–36, SO 3, IO 5, POM 5 (2+3), ST 1. FIN RAYS: PAD 39–42, PR 11–14. VeRTeBRAe: PDV 14–20, PAV 28–38, PCV 45–54, TV 173–183.

BODY eLONgATe, DORSAL-fIN ORIgIN BeHIND TIP Of PeCTORAL fIN BY A DISTANCe ABOUT eqUAL TO LeNgTH Of PeCTORAL fIN. HeAD SMOOTH, WITHOUT fLeSHY PAPILLAe DORSALLY, AND WITHOUT ROWS Of SMALL SeNSORY PITS VeNTRALLY ON HeAD AND ABDOMeN. ANTeRIOR eND Of UPPeR AND LOWeR LIPS WITH fLeSHY LOBeS AND RIDgeS. TeeTH SMALL, CONICAL, MULTISeRIAL ON

MAxILLA AND DeNTARY, ROWS WIDeR AT ANTeRIOR eND; INTeRMAxILLARY TeeTH SOMeWHAT LARgeR, CONICAL, IN ABOUT 2 IRRegULAR TRANSVeRSe ROWS; VOMeRINe TeeTH SMALL, IN A SHORT OVAL PATCH, ReACHINg LeSS THAN HALfWAY TO eND Of MAxILLARY TOOTH ROW.

BODY gReY WITH A HINT Of PINK-PURPLe COLOR; HeAD PINK-ReD IN COLOR WHeN fReSH, DeeP-PURPLe WHeN PReSeRVeD. SMALLeR SPeCIMeNS WITH A feW SMALL BUT DISTINCT MeLANOPHOReS AT INTeRVALS ALONg MIDDLe Of BODY, PROBABLY ReMNANTS Of LARVAL PIgMeNT.

MAxIMUM SIze ABOUT 800 MM TL.

Distribution. KNOWN fROM A feW WIDeLY SCATTeReD LOCATIONS IN THe INDIAN OCeAN AND WeSTeRN CeNTRAL PACIfIC: eAST COAST Of MADAgASCAR; MAKASSAR STRAIT, INDONeSIA (HOLOTYPe); NORTHeASTeRN BORNeO, MALAYSIA (PARATYPe); TAIWAN; AND VANUATU. DePTH 635–1012 M.

Remarks. THe NUMBeR AND PLACeMeNT Of THe POM POReS DeSeRVeS COMMeNT. We COUNTeD fIVe Of THeSe, ALL VeRY SMALL, THe fIRST TWO IN THe MANDIBULAR SeCTION NeAR THe TIP Of THe LOWeR jAW, AND THe LAST THRee IN A ROW IN THe LOWeR PART Of THe PReOPeRCULAR SeCTION BefORe IT TURNS DORSALLY TOWARD THe ANTeRIOR eND Of THe LL CANAL. ROBINS AND ROBINS (1971) DeSCRIBeD THeSe SOMeWHAT DIffeReNTLY, fROM BACK TO fRONT, BegINNINg WITH TWO SMALL POReS AT THe UPPeR eND Of THe PReOPeRCULAR CANAL CLOSe TO ITS jUNCTION WITH THe LL CANAL. We SAW THeSe TWO POReS, VeRY SMALL AND PAPILLA- LIKe, ON THe LefT SIDe AS ILLUSTRATeD IN ROBINS AND ROBINS (1971: fIg. 1), BUT We DID NOT fIND THeM ON THe RIgHT SIDe OR IN OUR SPeCIMeNS fROM TAIWAN. THeY MAY Be ANOMALOUS OR IRRegULAR. WHAT ROBINS AND ROBINS DeSCRIBeD AS THe SIxTH POM PORe LOCATeD BeHIND THe gAPe We INTeRPReT AS THe fIfTH IO PORe, WHICH IS IN THe SAMe POSITION IT OCCUPIeS IN MOST OTHeR CONgRIDS. ROBINS AND ROBINS DeSCRIBeD A SeVeNTH POM PORe “jUST ANTeRIOR TO THe CORNeR Of THe gAPe ALONg THe NeARLY TRANSVeRSe LOWeR jAW.” We WeRe UNABLe TO fIND THIS PORe IN THe HOLOTYPe OR IN OUR SPeCIMeNS.

THIS IS THe MOST DISTINCTIVe SPeCIeS Of Macrocephenchelys , WITH ITS gReATLY eLONgATe BODY, SMALL HeAD, POSTeRIOR DORSAL-fIN ORIgIN, AND THe ABSeNCe Of SeNSORY PITS VeNTRALLY. THe fLeSHY LOBeS AND RIDgeS ON THe SNOUT ARe MORe eLABORATeLY DeVeLOPeD HeRe THAN IN THe OTHeR SPeCIeS. THIS SPeCIeS WAS ORIgINALLY DeSCRIBeD fROM INDONeSIA AND MALAYSIA, BUT THe gReAT MAjORITY Of SPeCIMeNS KNOWN TODAY ARe fROM TAIWAN, WHeRe IT SeeMS RATHeR COMMON IN DeeP WATeR . TAIWAN SPeCIMeNS WeRe ALL COLLeCTeD fROM MARKeTS, AND THeRe IS NO PReCISe INfORMATION ON DePTH Of CAPTURe. THe HOLOTYPe AND PARATYPe WeRe COLLeCTeD AT 635 AND 1012 M, WHICH IS SIgNIfICANTLY DeePeR THAN THe OTHeR THRee KNOWN SPeCIeS. THe RATHeR fLABBY AND DeLICATe BODY IS CHARACTeRISTIC Of fISHeS THAT LIVe IN gReATeR DePTHS. THe ADDITIONAL ReCORDS fROM MADAgASCAR ( KARReR, 1983) AND VANUATU (THe PReSeNT STUDY) SUggeST THAT IT PROBABLY OCCURS IN MUCH Of THe INTeRVeNINg AReA AS WeLL.

KARReR (1983:48) ReCORDeD A SINgLe LARge Macrocephenchelys brachialis SPeCIMeN (MNHN 1979-68, 703 MM TL) fROM THe MOzAMBIqUe CHANNeL. IT IS THe fIRST AND ONLY ReCORD Of Macrocephenchelys SPeCIeS fROM INDIAN OCeAN. THIS SPeCIMeN HAS A SMALLeR eYe THAN THe PACIfIC SPeCIMeNS (6.5 VS. 10.0–18.7 % HL), WHICH MIgHT INDICATe THAT IT IS SPeCIfICALLY DISTINCT. HOWeVeR, IT IS NOT CeRTAIN HOW KARReR ReCORDeD THAT MeASUReMeNT. If SHe USeD THe PIgMeNTeD eYe RATHeR THAN THe PORTION Of THe eYe COVeReD BY THe CLeAR “SPeCTACLe,” THeN THe ReCORDeD SIze WOULD Be SMALLeR. IN LIgHT Of THIS UNCeRTAINTY AND THe LACK Of COMPARATIVe MATeRIAL, We ReTAIN THIS SPeCIMeN IN Macrocephenchelys brachialis . THe VANUATU SPeCIMeN IS A jUVeNILe AND DOeS NOT SHOW ANY SIgNIfICANT DIffeReNCeS fROM THe MORe NORTHeRN SPeCIMeNS.

ROBINS AND ROBINS (1971:132) RePORTeD 182 VeRTeBRAe (exPReSSeD AS 45 PRe-CAUDAL AND 137 CAUDAL) IN THe HOLOTYPe , BUT SMITH (1994:9) gAVe THe TOTAL NUMBeR AS 179. We x-RAYeD THe SPeCIMeN AgAIN AND COUNTeD 177 OR 178. THe UNCeRTAINTY IS CAUSeD BY THe 173rd VeRTeBRA , WHICH APPeARS TO Be DOUBLe. DePeNDINg ON WHeTHeR THIS IS COUNTeD AS ONe OR TWO VeRTeBRAe, THe TOTAL COUNT IS 177 OR 178 . BASeD ON THe fORM Of THe HYPURAL, THe TAIL APPeARS TO Be COMPLeTe.

Figures

FIGURE 2. Macrocephenchelys brachialis, TOU-AE6687, 561 mm TL, B. NMMB-P20807, 765 mm TL.

FIGURE 3. Head and anterior body With pores of three species of Macrocephenchelys. A. M. brachialis. B. M. brevirostris. C. M. nigriventris sp. nov.