Narcine baliensis, De Carvalho, Marcelo R. & White, William T., 2016

De Carvalho, Marcelo R. & White, William T., 2016, Narcine baliensis, a new species of electric ray from southeast Asia (Chondrichthyes: Torpediniformes), Zootaxa 4127 (1), pp. 149-160 : 150-158

Narcine baliensis , new species

( Figs. 1–6 , Tables 1, 2 )

Narcine indica [not of Henle, 1834].— Gloerfelt-Tarp & Kailola, 1984: 36, figure (occurrence in Indonesia, outline illustration of " N. indica " [= N. timlei ] compiled from Day, 1875).

Narcine sp. nov. G.— Carvalho, 1999: 257 –262, figs. 94, 95, tab. 40 (identification, description, distribution, illustrated, color photographs).

Narcine sp. D.— Carvalho et al., 2000: 1442, figure (brief account, identification; illustrated); White et al., 2006: 210, figured (general account; their material is designated as paratypes herein).

Holotype. NHM 1984.4.11.2, 306 mm TL, adult female, Indonesia, between the islands of Bali and Lombok, 8°37'S, 115°59'E, 60–63 m, JETINDOFISH trawling survey of S. Indonesia, 19.viii.1980 ( Fig. 1 ).

Paratypes. (3 specimens). CSIRO H 5858-04, 252 mm TL, juvenile? female, field no. C7, Cilacap fishing port, southern coast of Central Java, Indonesia, 7°40'S, 109°E, Indo-Oz market survey project, 2001 or 2002 ( Fig. 2 ); CSIRO H 5858-03, 143 mm TL, juvenile male (same data as CSIRO H5858-04) ( Fig. 3 ); MZB 23016, 160 mm TL, juvenile male, field no. C66 (same data as CSIRO H5858-04) ( Fig. 3 ).

Diagnosis. A species of Narcine distinguished from congeners by its unique dorsal color pattern, composed of large, circular, ovoid or elongate dark brown blotches on dorsal disc, interspersed with more numerous small (about eye-sized or greater) brownish, circular to ovoid spots, with large and small spots and blotches surrounded by a very slender creamy-white pattern, on a light brown to tan background color. Narcine baliensis is distinguished from N. brevilabiata and N. atzi , species that also possess few large brownish spots or blotches and numerous smaller spots, by having much fewer small spots or blotches, and by having the creamy-white, slender outline surrounding large and smaller spots and blotches on dorsal mid-disc. Additionally, N. baliensis is distinguished from N. brevilabiata by having much fewer small dark spots, and tooth bands of subequal width that are broadly circular in outline (vs. many small dark spots, and strongly subtriangular tooth bands, with upper tooth band clearly wider than lower tooth band in N. brevilabiata ), and from N. atzi by having fewer smaller spots, and dorsal fins subequal in height and length of base or first dorsal fin just slightly greater than second (vs. more numerous small spots, smaller than eye-diameter, and first dorsal fin conspicuously greater and with longer base than second dorsal fin in N. atzi ). Narcine baliensis is also distinguished from the Indo-West Pacific and Indian Ocean species N. maculata , N. lingula and N. prodorsalis , by having the preoral distance greater than preorbital distance (about equal in former three species); and from the western Indian Ocean N. oculifera and N. insolita , N. baliensis is further distinct in having dorsal fins of subequal size (first dorsal fin much larger than second in N. oculifera and N. insolita ).

Description. Disc thick, fleshy, and somewhat circular, wider than long (disc width 51.3% TL, disc length 47.1% TL). Disc tapers slightly as of level of eyes, anterior to level of greatest disc width. Disc widest slightly posterior to mid-disc. Snout rounded and broad, relatively long (preorbital snout length 11.5% TL; preoral snout length 13.8% TL); preorbital snout length around one-fourth of disc length. Disc barely overlapping origin of pelvic fins posteriorly, and projecting forward only slightly before contacting lateral aspect of trunk (leaving a faint notch in between disc and trunk). Electric organs extend from level of eyes to posterior four-fifths of disc; electric organ length 22.9% TL, electric organ width 9.3% TL. Gill slits relatively close together. Gill slits straight, not semi-circular, and slightly directed anteriorly at mid-line. Gill slits situated progressively closer to mid-line from first to last gill slit. Eyes and spiracles without gap in between. Eye diameter and spiracle width about equal.

Spiracles broad circular, wider than long, and situated at a slight angle in relation to eyes. Spiracles with slightly elevated borders (usually flattened in preserved specimens).

NHM 1984.4.11.2 CSIRO H5858-04 CSIRO H5858-03

Holotype Paratype Paratype

betw. Bali and Lombok Java Java

Character adult female juvenile (?) female juvenile male Mean S.D. ......continued on the next page Nasal curtain short and wide, more than twice as wide as long, with more or less straight posterior margin, and lacking significant median posterior projection ( Fig. 4 ). Lateral margins of nasal curtain straight, without lateral lobes. Nasal curtain only partially covering upper exposed tooth band, but nasal curtain pulled anteriorly due to preservation. Nasal curtain pores continue posteriorly to just beyond level of nostrils. Nostrils small and circular, with very small and inconspicuous elevated border posteriorly, but not flap-like. Prenasal snout length just over one-tenth in total length, about equal to preorbital snout length. Mouth wider than internarial width, mouth corners project laterally to just beyond level of outer margin of nostrils. Upper exposed tooth band slightly wider than lower exposed tooth band; both tooth bands broadly circular in outline, much wider than long. Teeth very small and numerous, in 26/21 vertical exposed rows in holotype. Teeth with small cusps even on inner, non-exposed tooth rows; teeth with posteriorly rounded, rhomboidal bases.

Pelvic fins relatively long and wide; pelvic fin width 37.4% TL, pelvic fin length 20.2% TL. Pelvic fins conspicuously wide anteriorly, with prominent, curved apices. Pelvic fin lateral margin slightly concave in preserved specimens. Pelvic fins originate just underneath posterior aspect of disc and extend caudally to level of mid-base of first dorsal fin. Pelvic fin insertion leaves a small free lobe. Tail stout, its length almost equal to disc length, and 47.4% TL as measured from cloaca. Tail tapers significantly from base to tip of caudal fin (tail width measured at base more than 20% TL). Lateral tail folds prominent, flap-like, originating on lateral tail at level in between first and second dorsal fin base, and continuing caudally to insert on ventrolateral caudal peduncle. Dorsal fins large and about equal in height and length of base (holotype), or first dorsal slightly greater than second dorsal fin (paratypes). Dorsal fins slightly differently shaped in holotype; first dorsal fin more erect and more rounded at apex, second dorsal fin with more slanted anterior margin and more pointed apex. First dorsal fin originates over posterior lobes of pelvic fins. First dorsal fin also broader at mid-height compared to second dorsal fin. Dorsal fins leave slight free lobe posteriorly as they inflect anteriorly to insert on dorsal tail; dorsal fins with more or less straight or upright posterior margins. Caudal fin tall and prominent. Upper caudal lobe moderately slanted, with rounded but elongated apex. Posterior margin of caudal fin relatively straight but with curved lower lobe (more apparent in holotype). Dorsal lobe of caudal fin slightly greater than ventral lobe. Dorsal and ventral lobes of caudal fin begin at same level on caudal peduncle.

Pores of lateral line difficult to observe, not highlighted with darker pigments. Dorsal coloration of specimens prohibit clear observation of pores, but few and scattered pores visible dorsal to lateral tail fold (posterior extension of lateral canal), running parallel to it, and continuing caudally to end on lateral aspect of caudal fin base. Ventrally, many ampullary pores present on snout region, evenly distributed and closely packed. Pores continue to just posterior to level of nostrils on nasal curtain, present lateral to nostrils and mouth; two small groups of pores present posterior to mouth and close to branchial openings. Pores ventrally outlining anterior and lateral aspects of electric organs.

Coloration. Dorsal coloration highly distinctive, composed of relatively few, large (usually close to size of interorbital space), light and dark brown, circular to ovoid spots or blotches (slightly faded in holotype), with numerous smaller brown spots (close to spiracle length or eye-diameter in size). Lighter creamy white color present surrounding brown spots or blotches and in between darker spots and blotches especially on central disc (forming what appears to be a reticulate creamy white pattern in holotype) ( Figs. 1–6 ). The large brown spots or blotches vary greatly in size, ranging from larger than dorsal-fin base length to slightly smaller spots and blotches especially on central and peripheral disc regions. The smaller spots are more numerous and relatively smaller in larger specimens, as are the larger blotches (cf. Figs. 1 and 2 with Fig. 3 ). Larger blotches are fewer in number, and situated directly posterior to eyes, on mid-line of disc posterior to eyes, on central and lateral disc areas at mid-disc, and at tail base. Some of these larger blotches are circular, others are laterally elongated and oval, while others appear to be the result of fused smaller spots, such as on snout and lateral disc in paratypes. Dark, undefined blotches and streaks are present on dorsal region of pelvic fins, and over apex of dorsal and caudal fins. Pelvic and caudal fins outlined in creamy white. Ventrally, coloration uniform pale white, with darker, undefined gray bands on posterior pelvic and disc areas, and diffuse gray blotches sometimes on anterolateral disc. Light brown blotches also present on ventral tail region.

Geographical distribution. Known from four specimens from southern Indonesia ( Fig. 7 ). The holotype was collected during the JETINDOFISH Survey ( Gloerfelt-Tarp & Kailola, 1984) from between the islands of Bali and Lombok in depths of about 60 m. The paratypes were collected from the Cilacap fishing port in Central Java from bycatch landings of the local trammel net fishery, which operates off southern Java where it is based. The image of the live specimen ( Fig. 6 ) was taken farther east on the other side of Wallace's line from the island of Komodo. Narcine baliensis probably occurs at least off most of Java and the western Lesser Sunda Islands, therefore crossing Wallace's line between Bali and Lombok. As far as presently known, N. baliensis and the Australian species of Narcine (= Narcinops Whitley, 1940 ; Carvalho et al., unpubl.) are the only numbfishes to occur east of the line.

Etymology. Named in reference to the nearby island of Bali, close to the type locality between the islands of Bali and Lombok, Indonesia.

Biology. Largely unknown, but presumably feeds on small benthic invertebrates as do other numbfishes. The holotype and largest known specimen is female and presumably sexually mature at 306 mm TL. The largest male specimen is a juvenile 160 mm TL ( Fig. 3 C).

Comparisons with congeners. Although known from only a few specimens, N. baliensis is distinct from all other species of Narcine in possessing large spots or blotches together with small spots surrounded by a lighter creamy color on central disc, in conjunction with having broadly circular tooth bands that are similarly shaped and of subequal width, and dorsal fins of subequal size. In the Indo-West Pacific region, only N. brevilabiata and N. atzi have a color pattern that is similar in presenting few, large spots or blotches coupled with numerous small spots, but both of these species lack the whitish pattern surrounding the spots on dorsal disc present in N. baliensis .

Narcine brevilabiata , although similar to N. baliensis in aspects of dorsal color, has fewer large spots or blotches and more numerous smaller spots (usually smaller than eye-diameter), and has very narrow, triangular tooth bands, especially the lower tooth band, which is much narrower than the upper tooth band ( Bessednov, 1966; Carvalho, 1999; Carvalho et al., 2000). Narcine brevilabiata also occurs in the Indo-West Pacific (described from the Gulf of Tonkin off Vietnam), and is relatively common off Thailand ( Monkolprasit, 1984, 1990) and Vietnam ( Bessednov, 1966, 1969), and is present in China (as N. lingula by Liu, 1932; pers. obs.), Taiwan (as N. maculata , e.g. Teng, 1962; Chen & Chung, 1971; Chen & Joung, 1993), and surrounding shallow water regions (possibly in the Philippines as well). It has not been officially recorded from Indonesia but probably occurs at least off Sumatra.

Narcine baliensis is distinct from N. atzi , known from the Arabian Sea and Bay of Bengal, probably its most similar congeneric species in characters other than color pattern, on the basis of dorsal and caudal fin configuration, meristics, and coloration. Narcine atzi , as in N. brevilabiata , has more numerous smaller spots, smaller than eyediameter, which are present even inside spiracles, and fewer large spots than N. baliensis ; also, N. atzi does not have the whitish pattern surrounding spots on central disc as in N. baliensis ( Carvalho & Randall, 2003) . The first dorsal fin of N. atzi is distinctively larger than the second, and both dorsal fins are about equal in size or first dorsal is just slightly greater than second dorsal fin in N. baliensis . The pelvic fins of N. baliensis have broad, rounded apices, very different from the pelvic fins of N. atzi , which are relatively not as long and lack prominent lateral apices; however, more specimens are needed to verify this character. Both species have similarly shaped, broadly circular tooth bands. However, N. atzi has fewer teeth (20/ 19 in adult female holotype of 310 mm TL vs. 26/ 21 in 306 mm TL adult female holotype of N. baliensis ), and more vertebral centra (holotypes with 117 vs. 105, respectively; also Table 2 ) ( Carvalho & Randall, 2003); but comparisons with more specimens of both species are required.

Identification of species of Narcine in the Indo-West Pacific is still poorly known despite recent revisionary work on the genus in the region (e.g. Monkolprasit, 1990; Carvalho, 1999, 2008; Carvalho et al., 2000; Carvalho & Randall, 2003). This is mostly due to the lack of extensive series of specimens, as only few specimens from distant localities have been sampled and are available for study. There is significant morphological variation in species of Narcine from the area (as great or greater than in tropical to subtemperate western Atlantic Narcine ; Carvalho, 1999). In particular, the separation between the "uniformly spotted" species N. maculata , N. lingula and N. prodorsalis , and between them and N. brevilabiata , N. atzi and N. baliensis , is tenuous and requires more in depth study. All three "uniformly spotted" species also present variation in coloration, and although not typically characterized by having few larger spots or blotches and numerous smaller spots, as in N. brevilabiata , N. atzi and N. baliensis , their spots may vary in size within a single individual (especially in N. maculata and N. prodorsalis ). Furthermore, specimens of N. prodorsalis frequently have the dorsal and caudal fins with dark brown apices as in N. baliensis . These species, however, have proportionally longer preorbital snout areas, about equal to preoral snout distances ( Carvalho, 1999), whereas N. brevilabiata , N. atzi and N. baliensis have a shorter preorbital snout compared to preoral snout. But even given the variation observed in Indo-West Pacific Narcine species, it is clear that N. baliensis does not fall within the known variation of congeners with similar color patterns ( N. atzi and N. brevilabiata ) and oral morphology ( N. atzi ).

Figures

FIGURE 1. Holotype of Narcine baliensis, sp. nov., in dorsal (A) and ventral (B) views (NHM 1984.4. 11.2, 306 mm TL adult female, from between Bali and Lombok, Indonesia). Note disc slightly curled dorsally in B.

FIGURE 2. Female paratype of Narcine baliensis, sp. nov. (CSIRO H 5858 - 04, 252 mm TL, juvenile?) in dorsal (A) and ventral (B) view.

FIGURE 3. Male paratypes of Narcine baliensis, sp. nov. Dorsal (A) and ventral (B) view of CSIRO H 5858 - 03 (143 mm TL, juvenile), and dorsal view (C) of MZB 23016 (160 mm TL, juvenile). All specimens from southern coast of Central Java, Indonesia.

FIGURE 4. Illustration of Narcine baliensis, sp. nov., based on holotype (NHM 1984.4. 11.2, 306 mm TL, adult female; modified from Carvalho et al., 2000, courtesy of FAO).

FIGURE 5. Detail of oronasal region of Narcine baliensis, sp. nov., showing morphology of tooth bands (holotype, NHM 1984.4. 11.2, 306 mm TL, adult female).

FIGURE 6. Live specimen of Narcine baliensis, sp. nov., photographed off the Indonesian island of Komodo (specimen not collected; photograph courtesy of G. R. Allen).

FIGURE 7. Map showing known distribution of Narcine baliensis, sp. nov. Indicated are holotype (asterisk) and paratypes (western locality, Java); eastern occurrence is specimen from the island of Komodo (see Fig. 5).

Tables

TABLE 2. Meristic data taken from specimens of Narcine baliensis, sp. nov. B – D are paratypes. A: NHM 1984.4. 11.2 (holotype, adult female); B: CSIRO H 5858 - 04 (juvenile? female); C: MZB 23016 (juvenile male); D: CSIRO H 5858 - 03 (juvenile male). * = conservative count, one or more additional elements probably present. See Appendix for abbreviations.

Character	A	B	C	D	Mode
PRO	17	18	16*	18	18
MES	1 0	1 0	1 0	1 0	1 0
MET	6	6	–	–	6
TPR	3 3	3 4	–	–	–
PVR	18	18	16*	16	18
FDR	8	–	–	–	–
SDR	6	–	7	–	–
DCR	2 1	2 0	–	–	–
VCR	2 8	1 9	–	–	–
TCR	4 9	3 9	–	–	–
UTR	2 6	1 8	1 8	1 7	–
LTR	2 1	1 5	1 6	1 3	–
TC	24	26	25	26	26
PC	59	61	62	60	–
CC	22	18	20	19	–
TV	105	105	107	105	105
RIB	8	–	7	–	–