Neotrygon orientale, Last & White & Séret, 2016

Last, Peter R., White, William T. & Séret, Bernard, 2016, Taxonomic status of maskrays of the Neotrygon kuhlii species complex (Myliobatoidei: Dasyatidae) with the description of three new species from the Indo-West Pacific, Zootaxa 4083 (4), pp. 533-561 : 553-556

Neotrygon orientale sp. nov.

( Figs. 5d , 6d , 7d , 12 ; Table 2)

Neotrygon kuhlii Clade 2— Puckridge et al., 2013: p. 6. Neotrygon kuhlii 1— Naylor et al., 2012: p. 76, fig. 58.

Holotype. MZB unreg (ex CSIRO H 7858-01) (tissue accession GN4267), late-adolescent male 213 mm DW, Muara Kintap, South Kalimantan, Indonesia, 3°54.26′ S, 115°15.53′ E, 30 Nov 2006.

Paratypes. 5 specimens: CSIRO H 6130-01, female 254 mm DW, Muara Angke fish market, Jakarta, Indonesia, 6°06′ S, 106°48′ E, 4 Apr 2001 ; CSIRO 6136-01, female 240 mm DW, CSIRO 6136-04 , adult male 220 mm DW, Muara Angke fish market, Jakarta, Indonesia, 6°06′ S, 106°48′ E, 31 Jan 2003 ; CSIRO H 7099-09 (tissue accession GN4754), female 171 mm DW, Flamboyan Market , Pontianak, West Kalimantan, Indonesia, 0°2.34′ N, 108°59′ E, 12 Jul 2008 ; CSIRO H 7848-01 (tissue accession GN4619), female 343 mm DW, Singkawang fish market, West Kalimantan, Indonesia, 0°55.11′ N, 108°59′ E, 28 Jul 2007 .

Other material. 6 specimens: CSIRO 6136-02, adult male 238 mm DW, CSIRO 6136-03, female 223 mm DW, CSIRO 6136-05 , adult male 215 mm DW, Muara Angke fish market, Jakarta, Indonesia, 6°06′ S, 106°48′ E, 31 Jan 2003 ; CSIRO H 7099-10 (tissue accession GN4755), female 145 mm DW, CSIRO H 7099-11 (tissue accession GN4756), female 145 mm DW, Flamboyan Market , Pontianak, West Kalimantan, Indonesia, 0°2.34′ N, 108°59′ E, 12 Jul 2008 ; CSIRO H 7849-01 (tissue accession BW-A7737), female 290 mm DW, Muara Angke fish market, Jakarta, Indonesia, 6°06′ S, 106°48′ E, 8 Oct 2009 .

Diagnosis. A small Neotrygon of the kuhlii -complex (reaching at least 38 cm DW; males maturing at 22 cm DW) with the following combination of characters: disc much broader than long, width 1.2–1.3 times length; pectoral apices abruptly angular; snout fleshy, broadly rounded to weakly angular, angle 124–129°, length 1.9–2.5 times interorbital width; maximum width relatively well forward on disc, length from snout tip to pectoral-fin insertion 1.8–2 times and disc width 2.7–2.9 times horizontal distance from snout tip to maximum disc width; preoral length 1.8–2.2 times mouth width; internasal distance 1.3–1.6 in prenasal length; interspiracular distance 13–16% DW; nostril length 3.1–3.8% DW; nasal curtain width 8.9–10% DW; small mouth, width 7–7.5% DW; horizontal distance from cloaca to caudal sting base 48–56% of disc length; thornlets present in nuchal region and weakly developed in the lumbar regions in adults, absent from tail in all sizes; minute, widely-spaced dermal denticles present on mid-disc of large adults; pectoral-fin radials 105–110; total vertebral centra (including synarcual) 125–141, trunk centra (including synarcual) 36–42; blue spots on disc moderately large, largest 0.5–0.9 in eye width; few blue spots on medial belt, 0–6 (mean 0.4), largest 2.8–3.3% DW; mask-like marking rather pronounced, covered with dark peppery spots; ventral surface of disc with diffuse greyish submarginal bands; ventral tail fold dusky with darker edge.

Description. Disc rhombic, straight to convex anteriorly and not produced; much broader than long, width 1.26 times length in holotype (1.20–1.25 in paratypes); axis of greatest width of disc relatively well forward on disc, slightly forward of scapular region, its distance from snout tip 1.91 (1.82–2.03) times in distance from tip of snout to pectoral-fin insertion; body relatively robust, thickness 8.0 (7.6–8.1) times in disc width, raised slightly above cranium; apex broadly rounded, narrowly or abruptly angular, pectoral angle 88° (85–90°); posterior margin straight to undulate; free rear tip narrowly angular. Pelvic fins narrowly subtriangular, anterior margin almost straight, apex narrowly rounded, posterior margin moderately convex, united with inner margin (free rear tip indiscernible); rather small, length 21.4% (21.0–22.4%) DW; 1.22 (1.06–1.15) times width across fin bases. Claspers of adult males relatively small, narrow, depressed, tapering, acutely pointed apically; outer length (from axil of pelvic fin) 13.9% DW.

Tail moderately broad-based, tapering rapidly to caudal sting(s), with dorsal and ventral skin folds; base moderately depressed, broadly oval in cross-section, weakly convex above and below, width 1.51 (1.35–1.80) times depth; subcircular to rhomboidal in cross-section near origin of ventral skin fold, width 0.98 (0.99–1.17) times height at fold origin; tapering evenly in dorsoventral view posterior to caudal stings; moderately compressed below broken tips of caudal stings; sometimes damaged distally beyond folds; both dorsal and ventral skin folds prominent; tail very compressed, narrowly suboval in cross-section above mid ventral fold, width 0.62 (0.66–0.87) times depth; at end of fold weakly depressed, width 0.95 (0.82–0.98) times height; dorsal surface of tail posterior to caudal-sting bases with a weak naked groove; no skin folds present along lateral margin of tail. Dorsal skin fold well developed, short-based, pronounced, length about 9 (9–12) times its height, 1.91 (1.57–2.08) in snout length, 6.68 (6.58–7.50) in length of ventral fold; its height 1.06 (1.45–2.01) in height of mid-ventral fold; origin usually with a short low ridge before elevated portion; elevated portion much shorter than snout length. Ventral skin fold relatively long, 49.9 (47.1–60.1)% DW, very narrow, tapering, deepest forward of dorsal skin fold; much longer based and slightly taller than dorsal skin fold; length 2.01 (1.66–2.12) in disc width; depth at quarter length 0.34 (0.52–0.82), at mid length 0.54 (0.76–0.87), at three quarter 0.42 (0.70–1.01) in adjacent tail height; originating almost below or just forward of first sting origin; horizontal distance from cloaca to sting origin 1.66 (1.48–1.72) in precloacal length.

Snout fleshy (more so in large paratypes), short, broadly rounded; not acute at apex, but without obvious apical lobe; angle 126° (124–129°); narrowly rounded when viewed laterally, becoming marginally more depressed towards apex; preoral snout length 1.99 (1.75–2.15) times mouth width, 1.81 (1.70–2.13) times internarial distance, 0.91 (0.74–0.95) times distance between first gill slits; preorbital snout short, direct length 2.45 (1.90–2.42) times interorbital length; snout to maximum disc width 2.83 (2.67–2.85) in DW; interorbital space almost flat, narrow; eyes large, dorsolateral, strongly protruding (less obvious in some paratypes), ventral margin partly covered by thick skin fold; orbit greatly elevated above disc and interorbital space, diameter 0.84 (0.80–1.06) in spiracle length, eye length 1.14 (1.10–1.40) in spiracle length; inter-eye distance 2.63 (2.54–3.77) times eye length. Spiracles large, crescentic with dorsolateral opening; dorsal margin with a medial protuberance. Nostril slit-like, directed longitudinally to slightly oblique; lateral margin fleshy; anterior nasal fold internal, very narrow, membranous; broad oronasal groove present; internarial space 1.46 (1.33–1.61) in prenasal length, 2.03 (2.08– 2.38) times nostril length. Nasal curtain relatively narrow, skirt-like, short, width 1.69 (1.59–1.99) times length; weakly bilobed, posterior margin of each lobe moderately convex; surface crenulated, weakly papillate, medial groove not obvious, sparsely covered with minute pores; apices recessible within lateral margin of oronasal groove; lateral margin almost straight, smooth-edged, usually partly enveloped by narrow posterior fold of nostril; posterior margin lightly fringed, concave medially, vaguely following contour of lower jaw, usually overlapping lower jaw when mouth closed.

Mouth small, jaws strongly asymmetric; lateral grooves shallow, sometimes almost indistinct, curved slightly, extending from nostril to slightly below lower jaw, length much shorter than nasal curtain length; not projecting forward when open, not protrusible; skin on chin and margin of lower jaw not particularly fleshy, papillate; teeth of paratype CSIRO H 7848–01 uniformly close-set in both jaws, in oblique rows, not arranged in obvious quincunx, rows in upper jaw ~31, lower jaw ~35. Upper jaw strongly arched, strongly double convex; teeth of anterior part of upper jaw concealed when mouth closed; symphysial part of jaw projecting anteroventrally. Lower jaw strongly convex with a truncate to weakly concave anterior margin, interlocking into upper jaw when mouth closed; teeth not visible when mouth closed. Upper jaw of adult female paratype ( CSIRO H 7848–01) with a raised row of enlarged teeth with elongate blunt cusps (directed lingually) near the middle of each side of jaw; teeth otherwise similar in shape, cusps shorter than their base length; teeth at symphysis barely larger than those laterally, cups small and directed lingually. Teeth in lower jaw broad based, low, with short knob-like cusps and convex anterior margins; those toward angle of lower jaw with slightly shorter cusps. Floor of mouth in paratypes with two very long, lobe-like, very closely spaced, medial oral papillae (holotype not dissected); no smaller papillae near angle of each jaw.

Gill openings elongate S-shaped, fringe not discernible; length of first gill slit 1.14 (1.28–1.59) times length of fifth gill slit, 2.36 (2.05–2.43) times in mouth width; distance between first gill slits 2.00 (2.03–2.30) times internarial space, 0.44 (0.43–0.46) times ventral head length; distance between fifth gill slits 1.13 (1.13–1.26) times internasal distance, 0.25 (0.24–0.25) times ventral head length.

Total pectoral-fin radials 109 (105–110); propterygium 42–43 (42–44), mesopterygium 17–19 (16–18), metapterygium 48–49 (45–49). Pelvic-fin radials: 1 (1) + 19–20 (19 in a male paratype, 23–26 in female paratypes). Vertebral centra total (including synarcual) 140 (125–141); total (excluding synarcual) 135 (122–141); monospondylous (including synarcual) 41 (36–42); monospondylous (excluding synarcual) 36 (33–35); pre-sting diplospondylous 65 (61–70); post-sting diplospondylous 34 (25–29).

Squamation. Disc and tail of holotype lacking dermal denticles; a single median row of 4–8 variable-length, spear-shaped to narrow lanceolate thornlets on nape, anteriormost thornlets slightly smaller than those at end of row; no thornlets on lumbar region or tail; row length 8–11% DW when present, less than ¾ of interspiracular width; angle much less than 45° to horizontal (appearing vaguely saw-shaped in lateral view); lateral scapular thorns absent. In largest paratype ( CSIRO H 7848-01), row of thornlets on nape disjunct from short anterior lumbar row (no thornlets on posterior disc or tail); wide band of minute, upright, widely-spaced dermal denticles extending from interorbit to tail base (evident to the eye as minute specks and barely detectable to touch).

One caudal sting on holotype (two broken stings in largest paratype), not intact; enveloping membrane absent; distance from cloaca to sting base 0.48 (0.48–0.56) in disc length.

Colour. Live coloration (based on holotype). Dorsal surface pale yellowish brown centrally and blue-spotted, graduating to translucent margin of disc and pelvic fins; eye whitish, orbital membrane similar to disc. Blue spots medium-sized, irregularly spaced, weakly ocellate, with faint blue centres and surrounded by only slightly darker blue, diffuse-edged outer rings; distributed mainly over central parts of pectoral fins; present on through medial belt; thornlets in medial row white and contrasted with adjacent skin; dark speckles mostly concentrated around mask; mask-like marking on head rather pronounced, with dense peppering of dark speckles on and around orbits. Ventral surface largely white, marginal band around disc greyish and diffuse edged. Tail similar to disc colour dorsally before caudal sting, darker with black and white or yellowish bands toward its tip; dorsal fold pale, similar to dorsal tail; ventral fold dusky with darker edge.

In preservative (based on holotype). Dorsal surface pale greyish brown; mask well-developed and contrasting with anterior disc, distributed over orbital membranes and in bands between orbits, forward of orbits and blotches besides orbits (two large pale blotches on interorbital space), peppering of small black spots well-developed on mask (less obvious in paratypes); dark blotch but no extended marking on nape; bluish spots medium-sized (in paratypes largest spots 2.5–5% DW), appearing as greyish blue markings with no or indistinct pale centres (rarely ocellate). Ventral surface of disc and pelvic fins predominantly white with narrow dusky edges; submarginal bands barely detectable, weak and diffuse-edged in smallest types (absent in largest paratype). Tail much darker dorsally than ventrally; ventral surface forward of ventral fold largely pale (occasionally with some dusky patches); ventral fold dark distally, sometimes with a very narrow pale base, strongly contrasted with ventral surface of tail anteriorly; dorsal fold uniformly dusky; banding on post-fold tail primarily blackish with 4 pale dusky bands (banding on paratypes variable); sting bases greyish white. Claspers only marginally paler than dorsal tail; ventral surface slightly paler than dorsal surface.

Size. Type specimens consisted of an adult male of 220 mm DW, a late-adolescent male of 213 mm DW, and four females of 171–343 mm DW. White & Dharmadi (2007, as Dasyatis cf. kuhlii Java form) reported a size at 50% maturity for males of 237 mm DW and a maximum size for females and males of 379 and 324 mm DW, respectively. They also reported that pregnant females contained only a single pup with a size at birth of ~ 120 mm DW.

Distribution. Type specimens taken from fisheries bycatch and fish landing sites in Kalimantan and West Java (Jakarta) in Indonesia ( Fig. 8 ). Additional specimens also taken from Malaysian Borneo and the Philippines ( Naylor et al., 2012). Specimens taken from the Muara Angke landing site in Jakarta were predominantly caught by trap fisheries operating off Sumatra thus its presence in Java is not confirmed. Accurate depth information not available but probably found mostly inshore in depths of less than 100 m.

Etymology. Epithet demarcates the South-East Asian distribution of this member of the bluespotted maskray complex within the genus Neotrygon . Vernacular: Oriental Bluespotted Maskray.

Figures

FIGURE 5. Oronasal region of: (A) Neotrygon kuhlii (CSIRO 7723 - 01, female 295 mm DW); (B) Neotrygon australiae sp. nov. (CSIRO CA 3247, adult male 379 mm DW); (C) Neotrygon caeruleopunctata sp. nov. (CSIRO H 6202 - 03, adult male 311 mm DW); (D) Neotrygon orientale sp. nov. (CSIRO H 6130 - 01, female 254 mm DW).

FIGURE 6. Lateral view of the post-caudal sting tail of: (A) Neotrygon kuhlii (CSIRO 7723 - 01, female 295 mm DW); (B) Neotrygon australiae sp. nov. (CSIRO CA 4307, female 306 mm DW); (C) Neotrygon caeruleopunctata sp. nov. (CSIRO H 6202 - 04, female 324 mm DW); (D) Neotrygon orientale sp. nov. (CSIRO H 7848 - 01, female 343 mm DW).

FIGURE 7. Lateral view of the mid-tail showing respective heights of the dorsal and ventral tail folds: (A) Neotrygon kuhlii (CSIRO 7723 - 01, female 295 mm DW); (B) Neotrygon australiae sp. nov. (CSIRO CA 4307, female 306 mm DW); (C) Neotrygon caeruleopunctata sp. nov. (CSIRO H 6202 - 04, female 324 mm DW); (D) Neotrygon orientale sp. nov. (CSIRO H 7848 - 01, female 343 mm DW).

FIGURE 8. Map showing the locations of the type material and other specimens examined of Neotrygon kuhlii (blue), Neotrygon australiae sp. nov. (red), Neotrygon caeruleopunctata sp. nov. (green) and Neotrygon orientale sp. nov. (yellow). Stars denote primary types (holotype or lectotype), solid circles denote secondary types, and open circles denote non-type material examined.

FIGURE 12. Holotype of Neotrygon orientale sp. nov. (MZB unreg [ex CSIRO H 7858 - 01]), late-adolescent male 213 mm DW) from South Kalimantan, Indonesia (fresh): (A) dorsal view; (B) ventral view.