Rev. Biol. Trop., 46(2): 439-446, 1998

Gymnothorax. phalarus, a new eastern Pacific moray (Pisces: Muraenidae)

William A. Bussing 1

Escuela de Biología & Centro de Investigación en Ciencias del Mar y Limnología (CIMAR), Universidad de Costa Rica, 2060 San José, Costa Rica; [email protected]

Received 2-111-1997. Corrected 27-1-1998. Accepted 19-11-1998.

Abstract: Gymnothoraxpllalarus is describedfrom 23 individuals taken in trawl and dredge collections made on the Pacific coast of Costa Rica. The new species is nearly always syntopic with a similar species, . The new moray is distinguished by its white-spotted pattem, uniserial, slightly serrated teeth in adults, four infraorbital pores andmean vertebral formula of 6-58-140. Ofthe total of 21 valid species of morays recorded from thePacific coast of Costa Rica, only the new species and G. equatorialis form part of the trawl fishery as the remainder are almost entirely restricted to nearshore rocky habitats. The known range of G. plla/arus is from Baja Californiato Pern.

Key words: New species, eastern Pacific, Pisces: Muraenidae, .

The moray eel fauna of the Pacific coast members of Neomuraena which have three of Costa Rica is abundant and diverse. To date, infraorbital pores, the new species, described 19 valid species of morays have been recorded herein, possesses four infraorbital pores and from nearshore rocky habitats and another two slight1y serrated uniserial teeth and possibly species by trawling in deeper waters over soft belongs to another subgenus. substrata. Nine of these , inc1uding the two deep-water species, belong to the Methodology follows (Bohlke 1982 & Gymnothorax. In addition, Bohlke et al. Bohlke et al. 1989). Institutional acronyms (1989:149;172) referred to the presence in the follow Leviton et al. (1985). AH measurements eastem Pacific of oQe or two unidentified are expressed in millimeters (mm) and length species of Gymnothorax of the subgenus is total length (TL) throughout. Specimens are Neomuraena similarto several Neomuraena in deposited at LACM and UCR. the westem Atlantic.

Trawl samples on the Pacific coast of Gymnothoraxphalarus, new species Costa Rica routinely yield fair numbers of the (Figs. 1-4) white-spotted Gymnothorax (Neomuraena) equatorialis (Hildebrand) and a similar less­ Gymnothorax sp. nov. Bus�ing & López common, undescribed species (Fig. 1). Unlike 1993 (figure legend and description inverted 440 REVISTA DE BIOLOGIA TROPICAL

Fig. J. Gymnothorax phalarus, n. sp., holotype, LACM 47317-1, 565 mm TL, Isla del Caño, Costa Rica.

with G. equatorialis); Bussing & López 1, 2 (468-620), SW of Cabo Blanco, Nicoya 1996 (listed). Peninsula, 275-339 m, 7-8 May 1970. LACM 47320-1,5 (352-598),8 km offshore of Bahía Holotype: LACM 47317-1, an adult Henadura, 184 m, 10 Feb. 1984. LACM female of 565 mm total length (TL),W side of 47319-1, 1 (523), off Punta Coyote, Nicoya Isla del Caño off Osa Peninsula, Costa Rica. Peninsula,83 m,31 Oet. 1983. VCR 427-16,1 (8°47'00" N; 84°03'48" W). Colleeted with 3 (339), between Cabo Blanco and Punta m dredge at 136-237 m depth on 12 Feb. 1994 Henadura,220 m,19-21 May 1970. VCR 489- by M.L W.A. Bussing and crew of RN Victor 17, 1 (570), Golfo de Nicoya, 23-25 m, 26-29 Hensen,(ex VCR 2373-12). Oel. 1970. VCR 1242-4, 1 (660), coast N of Cabo Velas, 118-139 m, 5 Dec. 1977. UCR Paratypes: Data is presented as follows: 1555-1,3 (397-927),off Punta Coyote,Nicoya catalog number, number of specimens, length Península,80 m, 30 OcL 1983. VCR 1711-2,1 in mm TL and collection data. AH speeimens (283), 1.2 km offsbare of Punta Leona, 54 m, are from Costa Rica. Additional data are 7 Dec. 1983. VCR 1730-6, 2 (420-437),6 km available on the Internet. offshore of Malpaís,Nícoya Peninsula,295 m, 12 Feb. 1984. VCR 1963-4, 1 (603), off Punta LACM 32560-13, 1 (485 mm), Isla del Coyote, Nicoya Peninsula, 65 m, 23 May Caño, 55-73 m, 17 Mar. 1972. LACM 47318- 1987. UCR 2353-14, 3 (505-755). Golfo BUSSING: Gymnthorax phalarus, a new eastern Pacific moray eel (Pisces: Muraenid<\e) 441

Dulce, at center of entrance to gulf, 130-268 at gill opening greatest in large specimens, 11.2- m, 15 Dec. 1993. UCR 2366-1,1 (402),Golfo 19.2 (11.9) times in 1L, depth at anus 14.1-25.4 Dulce, just outside entrance to gulf, 200 m, 10 (15.2) in 1L; tapering gradually and becoming Feb. 1994. UCR 2372-6,1 (400),off mouth of more compres sed posteriorly. Predorsal distance Río Sierpe, 103 m, 12 Feb. 1994. 7.2-11.1 in 1L(determined on radiographs of 8 paratypes). Anus slightly before or after Comparative Material: Gymnothorax rnidbody, preanal distance 1.9-2.2 (2.2) in 1L; equatorialis from Mexico(3 specimens) and tail length 1.9-2.2 (1.9) in 1L. from Costa Rica (63 specimens) are deposited at LACM and UCR. Gymnothorax castaneus Head length 5.-4-6.4 (5.6) in Tl:;; eye - (13 specimens) and G. dovii (33 specímens) slight1y in advance of mid-jaw, 10.4-21.4 (13.7) from Costa Rica and Isla del Coco are in head length(HL). Fleshy interorbital space deposited at UCR. Additional data for UCR convex, width 7.2-11. 2 (9. 2) in HL. Snout collections is available on Internet. length 5.1-6.9 (6.6) in HL. Anterior nostril tubular, near tip of snout; posterior nostril with Diagnosis: A moderately deep-bodied a slightly raised margin, near anterodorsal moray of the genus Gymnothorax, with: margin of eye. Gill opening in form of an medium to . dark brown coloration overlain oblique slit slightly aboye or at rnid-side. with white dots bt?coming larger posteriorly; jaw teeth urlisetial ahd serrate; one or two Head pores(Fig. 2) usually rimmed with vomerine teeth in adu1ts; four infraorbital darker pigment. Four conspicuous infraorbital pores; and mean vertebral formula(MVF) 6- pores; three smaller supraorbital pores; 58-140. mandibular pores 5-7, usually 6(holotype with 6-7). Description: Measurements in percentage of 1L appear in Table 1. In the following, Jaws of equal length or lower jaw proportions of the holotype are in parentheses extending slightly, snout to rictus(upper jaw following the mnge of 15 paratypes. Body depth length) 2.1-2.9 (2.6) in HL. Teeth sharp, slender and uniserial with margins most strongly serrated on posterior edge. On upper jaw usually an anterior median fang, followed on each side by three or four widely-spaced TABLE 1 long intermaxillary teeth, and followed by Proportional measurements in percentage of total length about eight maxillary teeth, the teeth evenly of holotype, 15 paratypes of Gymnothorax phalarus from spaced and decreasing in size posteriorly(Fig. the Pacific coast of Costa Rica 3A). On lower jaw, a single row of 11-15 teeth,

Holotype Paratypes Paratypes N=lO N=5

Total length (mm) 565 283-445 577-929 Head length 17.9 15.6-17.6 16.5-18.7 Eye diameter 1.3 1.0-1.6 0.9-1.3 Fleshy interorbital 2.0 1.4-2.2 1.7-2.6 Snout length 2.7 2.3-3.2 2.6-3.4 Jaw length 6.9 5.6-8.1 5.8-7.4 Body depth at gill open. 8.4 5.2-8.2 6.3-9.0 Body depth at ¡\nus 6.6 4.6-6.8 3.9-7.1 Predorsal distance 11.7 9.0-11.8 12.5-13.8 Preanal distancé 46.6 46.0-53.1 49.2-53.1 Fig. 2. Gymnothorax phalarus, n. sp., UeR 2353-14,505 Tail length 53.4 47.4-52.9 45.1-51.5 mm TL, head pore distribution. 442 REVISTA DE BIOLOGIA TROPICAL

Fig. 3. Comparisonof dentition of two deep-water morays from the same collection site, Peninsula de Nicoya, Costa Rica. A: Gymnothorax pha/arus, n. sp., paratypeLACM 47319-1, 462 mm TL. B: Gymnothorax equatorialis, 'VCR 1556-6, 460 mm TL. '

the anterior three to five, similar in size and vertebrae 138-144(140. 1). Holotype' with VF shape to intennaxillary teeth, the remainder value of 5-56-144. decreasing gradually in size posteriorly, but less so than in upper jaw. Depressible Coloration: Color of liveand preserved replacement teeth present, in process of specimens the same. Head and: trunk brown, becoming functional. Median intermaxillary becoming darker posteriorly to dusky teeth absent. One or two conical vomerine chocolate brown or black on tall. Eye rimmed teethonly on large specimens. in darkerpigment. Numerous small, pale, spots behind head, becoming fewer an'd larger(pupil Vertebral,counts (Table 2) based on to eye-diameter size) posteriorly; round or oval radiographs of holotype and 13 paratypes white spots very conspicuous on tail(Fig. 4A). (mealis in parendíeses): predorsal vertebrae 5- Spots on trunk fewer and less diktinct on sorne 8(6.3); preanal vertebrae 56-61(58.2); total specimens, more numerous and distínctly BVSSING: Gymnthoraxphalarus, a new eastern Pacific moray eel (Pisces: Muraenidae) 443

TABLE 2

Frequency distribution of numbers of vertebrae in Gymnothorax phalarus and G. equatorialis

Predorsal vertebrae: 5 6 7 8 x

G. phalarus 3 5 5 6.3 G. equatorialis 3 3 7.3 Preanal vertebrae: 51 52 53 54 55 5() 57 58 59 60 61 x

G. phalarus 4 2 3 2 58.2 G. equatorialis 3 4 1? 53.1 Total vertebrae: 138 139 140 141 142 143 144 145 146 147 148 149 x

G. phalarus 3 2 2 3 140.1 G. equatorialis 2 2 145.6

A B

Fig. 4. Comparison of tail pigmentation of two deep-water morays from Costa Rica. A: Gymnothorax phalarus, n. sp., paratypes VCR 1711-2 and 1209-3. B: Gymnothorax equatorialis, VCR 2364-2, 1209-3 and 2023-6.

white on others; head and abdomen brown or An immature specimen (283 mm) has straw-colored with few or no spots. Dorsal fin small white spots commencing at snout tip; also white-spotted, becoming nearly black on becoming larger ovals on branchial region; tail; anal fin black with few or no white spots. eye-sized white spots behind gill opening well- 444 REVISTA DE BIOLOGIA TROPICAL separated and contrasting with nearly black The reef morays Gymnothorax castaneus tail. The largest specimen, a 927 mm adult Gilbert and G. dovií (Günther) may be related male, is dark brown, nearly black on mid­ to and share several characteristics with G. dorsal line from snout to tail tip; head with a phalarus. They also have four infraorbital wide black ring around orbit; few well­ pores, similar MVF values, uniserial teeth(but separated white specks on trunk, becoming with an inner, median intermaxillary tooth) and more numerous and larger(pupil-sized) round anus near midbody. However the tail is more or oval spots on tail; dorsal fin black with robust, ending in a blunt tip and the median fins white spots, anal fin black without spots. are more elevated. The teeth are extremely finely serrated even on large specimens, Etymology: From the Greek phalaros whereas the teeth of G. phalarus are more meaning white-spotted; to be treated as an conspicuously serrate. Both reef species are adjective. found in nearshore rocky habitats and have not been collected by trawls in deeper water. Distribution: Known from Baja California, Mexico to Peru,(only Costa Rican Gymnothorax dovii is a dark brown or material was utilized in the present study). black eel covered with small (less than pupil Specimens of G. phalarus labeled size) white spots and can be. more readily "Gymnothorax C' or "Gymnothoraxsp." were confused with G. phalarus. whereas G. examined by the B6hlkes during their survey castaneus is brown or brownish green with on the -marginatus­ few white or yellow flecks mostly on the saxicola complex, and are deposited at several posterior half of body and dorsal fin institutions including SIO, LACM and USNM (McCosker & Rosenblatt 1975). (E. B6hlke, pers. comm.). Taken by trawl and dredge on soft substrata between 23 and at Two other, somewhat similar species, G.

least 295 m depth in Costa Rican waters. angusticeps (Hildebrand) andG. . serratidens (Hildebrand), reported only from Peru, have quite differentMVF values: 5-73-170 and 8-68- 156 respectively(B6hlke, 1982)"and differ in a REMARKS number of otherrespects (Hildebrand, 1949).

Although not necessarily closely related, Three other spotted .eels have been in general appearance, body shape and habitat, reported from the mid Pacific at Easter Island Gymnothorax phalarus resembles G. (Randall & McCosker, 1975). Gymnothorax equatorialis. Both species are dark, white­ nasuta De Buen has a dark reticulum spotted eels with uniserial jaw teeth and few or overlaying white spotting, the anterior nostril no vomerine teeth. The anus is located near is exceptionally long(6-7% of HL), several midbody and the tail tapers to a slender tipo inner median intermaxillaryfangs and a row of Gymnothoraxequatorialis is distinguished by several vomerineteeth. Gymnothorax eurostus its three infraorbital pores, different MVF (Abbott), in addition to a dense covering of values(Table 2), different jaw shape(Fig. 3B), minute white spots, presents larger (pupil often a median intermaxillary tooth, and by a diameter) black spots on the anterior third of narrower tai1 with very elongate(longer than the body; biserial maxillary teéth, three rows

eye diarneter), widely-spaced, terminal spots of intermaxillary fangs, a . .fQW of several (Fig. 4B). Terminal spots on the tail of G. vomerine teeth and the .. Easter Island phalarus(Fig. 4A) are round or oval, smaller specimens have 124-128 total vertebrae. than eye diarneter, and more closely spaced. Randall & McCosker (1975) placed BUSSING: Gymnthorax phalarus, a new eastem Pacific moray eel (Písces: Muraenidae) 445

Gymnothorax dentex De Buen in the nothorax equatorialis. La nueva morena se distingue por synonymy of G. eurostus and described the su patrón de puntos blancos, dientes ligeramente aserrados y uniseriales en adultos, cuatro poros infraorbitales y MVF deep-water(250 m) Gymnothorax bathyphilus. (Fórmula de Vértebras) de 6-58-140. México a Perú. The latter species has similar dentition, but presents a light yellowish gray color with scattered dark brown blotches, mostly larger than eye and 145 total vertebrae. REFERENCES

B6hlke, E.B. 1982. Vertebral formulae for type specimens G. phalarus No attempt is made to place in of eels (Pisces: Anguilliformes). Proc. Acad. Nat. Sci. one oftne provisional sllogeneraofBéihlke et al. Plllladelphia 134: 3149. (1989) until further study and comparison with Indo-Pacific spycies is carried out. B6hlke, E.B., J.E. McCosker & J.E. B6hlke. 1989. Family Muraenidae. In: (E.B. B6h1ke, ed.) of the western North Atlantic. Sears Fdn. Mar. Res. Mem. (New Haven) 1: 104-206.

ACKNOWLEDGMENTS Bussing, WA. & M.I. López. 1993. Peces demersales y pelágicos costeros del Pacífico de Centro América meridional. Guia ilustrada (SpanlEnglish) Special I appreciate the assistance of B. Burgos, Pub. Rev. Biol. Trop. 164 p. C. Gamboa, M. Gauthier, E. Quesada and R. Rojas for collecting material; R. Lavenberg, R. Bussing, WA. & M.l. López. 1996. Fishes collected Feeney and J. Seigel(LACM) for providing during the Victor Hensen Costa Rica Expedition radiographs and G. Serrano for drawing the (1993/1994). Rev. Biol. Trop. 44, Suppl. 3: 183-186. figures. Previous drafts of the paper greatly Hildebrand, S.F. 1949. A collection of fishes from Talara, benefited from the critical scrutiny of E. Perú. Smithsonian Mise. Coll. 111: 1-36. Béihlke, J. McCosker and R. Rosenblatt. Contribution No. 111, Museo de Zoología, Leviton, A.E., R.H. Gibbs, Jr, E. Heal & C.E. Dawson. Universidad de Costa Rica and CIMAR 1985. Standards in herpetology and ichthyology: Part 1. Copeia 1985: 802-832. Contribution No. 281.

McCosker, J.E. & R.H. Rosenblatt. 1975. The moray eels (Pisces: Muraenidae) of the Galapagos Islands, with new records and synonymies of extralimital species. RESUMEN Proc. Calif. Acad. Sci. (Ser. 4) 40: 417-427.

Gymnothorax phalarus se describe con base en 23 Randall, J.E. & J.E. McCosker. 1975. The eels of Easter individuos de colecciones hechas por redes de arrastre y Island with a description of a new moray. Contrib. Sci., dragas en la costa Pacífica de Costa Rica. La especie nue­ Nat. Hist. Museum Los Angeles County 264: 1-32. va es casi siempre sintópica con la especie similar, Gym-