Neotrygon caeruleopunctata, 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 : 546-553
treatment provided by
Neotrygon caeruleopunctata sp. nov.
Neotrygon kuhlii Clade 6— Puckridge et al., 2013: p. 6.
Holotype. MZB unreg (ex CSIRO H 7852-03) (tissue accession BW-A2572), adolescent male 227 mm DW, Kedonganan fish market, Bali, Indonesia, 8°45′ S, 115°10′ E, 17 Apr 2004.
Paratypes. 9 specimens: CSIRO H 7851-01, adolescent male 295 mm DW, CSIRO H 7851-02, male 273 mm DW, Kedonganan fish market, Bali, Indonesia, 8°45′ S, 115°10′ E, 16 Apr 2004; CSIRO H 7852-01 (tissue accession BW-A2573), female 247 mm DW, CSIRO H 7852-02, female 280 mm DW, collected with holotype; CSIRO H 6202-03, adult male 311 mm DW, CSIRO H 6202-04, female 324 mm DW, Kedonganan fish market, Bali, Indonesia, 8°45′ S, 115°10′ E, 18 Apr 2004; CSIRO H 7850-01 (tissue accession BW-A5731), female 350 mm DW, Sadeng fishing port, Central Java, Indonesia, 8°11.5′ S, 110°48′ E, 18 Oct 2008; CSIRO H 6124-01 (tissue accession BW-A2580), female 264 mm DW, CSIRO H 6124-02, male 245 mm DW, Kedonganan fish market, Bali, Indonesia, 8°45′ S, 115°10′ E, 24 Aug 2002.
Diagnosis. A large Neotrygon of the kuhlii -complex (reaching at least 47 cm DW; males maturing at 31 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 obtuse, angle 125–130°, length 1.8–2.4 times interorbital width; maximum width relatively well forward on disc, length from snout tip to pectoral-fin insertion 1.9–2 times and disc width 2.6–2.9 times horizontal distance from snout tip to maximum disc width; preoral length 1.6–2.3 times mouth width; internasal distance 1.4–1.8 in prenasal length; interspiracular distance 13–14% DW; nostril length 2.5–3.5% DW; nasal curtain width 8–9.4% DW; small mouth, width 6.6–7.9% DW; horizontal distance from cloaca to caudal sting base 51–56% of disc length; thornlets present in nuchal and lumbar regions in large individuals, absent from tail in all sizes; dermal denticles entirely absent from body; pectoral-fin radials 105– 110; total vertebral centra (including synarcual) 133–142, trunk centra (including synarcual) 38–43; blue spots medium-sized, largest spot on disc 0.5–0.8 times eye width; 0–3 (mean 0.8) blue spots on medial belt, largest 1.7– 2.7% DW; mask-like marking dark, not covered with dark peppery spots; ventral surface of disc and pelvic fins with sharply defined dark greyish brown submarginal bands; ventral tail dark before caudal sting; ventral tail fold almost entirely dark in young.
Description. Disc rhombic, straight to weakly convex anteriorly and not produced; much broader than long, width 1.24 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 2.02 (1.86–2.02) times in distance from tip of snout to pectoral-fin insertion; body relatively robust, thickness 9.0 (7.7–9.1) times in disc width, raised slightly above cranium; apex broadly rounded to obtuse, pectoral angle 83° (81–87°); posterior margin straight to weakly undulate; free rear tip narrowly angular. Pelvic fins narrowly subtriangular, anterior margin almost straight, apex narrowly rounded, posterior margin convex, united with inner margin (free rear tip indiscernible); rather small, length 20.9% (20.6–21.9%) DW; 1.21 (1.08–1.28) times width across fin bases. Claspers of adult males relatively small, depressed, tapering, acutely pointed apically; outer length (from axil of pelvic fin) 12.5% DW.
Tail moderately broad-based, tapering rapidly to caudal sting (damaged in all types), with dorsal and ventral skin folds; base moderately depressed, broadly oval in cross-section, weakly convex above and below, width 1.48 (1.25–1.72) times depth; subcircular to rhomboidal in cross-section near origin of ventral skin fold, width 1.20 (1.00–1.21) times height at fold origin; tapering evenly in dorsoventral view posterior to caudal sting(s); moderately compressed beneath broken sections of caudal sting(s); damaged distally beyond folds in largest paratypes; both dorsal and ventral skin folds prominent; tail compressed, narrowly suboval in cross-section above mid ventral fold, width 0.70 (0.57–0.91) times depth; at end of fold subcircular, width 0.86 (0.84–1.12) times height; dorsal surface of tail posterior to caudal-sting bases with a weak naked groove (partly housing ventral-most sting); no skin folds present along lateral margin of tail. Dorsal skin fold well developed, short-based, pronounced, length about 12 (9–12) times its height, 1.35 (1.30–1.66) in snout length, 5.39 (5.20–6.09) in length of ventral fold; its height 1.34 (1.17–1.40) 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, 60.0 (49.9–60.3)% DW, relatively narrow, tapering, deepest forward of dorsal skin fold; much longer based and distinctly taller than dorsal skin fold; length 1.67 (1.66–2.00) in disc width; depth at quarter length 0.67 (0.55–0.75), at mid length 0.65 (0.52– 0.82), at three quarter 1.06 (0.75–0.97) in adjacent tail height; originating almost below or just forward of first sting origin; horizontal distance from cloaca to sting origin 1.59 (1.51–1.60) in precloacal length.
Snout fleshy (more so in large paratypes), short, obtuse; not acute at apex, but without obvious apical lobe; angle 128° (125–130°); narrowly rounded when viewed laterally, becoming slightly more depressed towards apex; preoral snout length 2.01 (1.63–2.34) times mouth width, 2.19 (1.75–2.28) times internarial distance, 0.83 (0.75– 0.95) times distance between first gill slits; direct preorbital snout rather short, length 1.78 (1.91–2.40) times interorbital length; snout to maximum disc width 2.94 (2.64–2.87) in DW; interorbital space narrow, weakly concave; eyes large, dorsolateral, strongly protruding, ventral margin partly covered by thick skin fold; orbit greatly elevated above disc and interorbital space, diameter 0.83 (0.88–1.02) in spiracle length, eye length 1.17 (1.27–1.45) in spiracle length; inter-eye distance 2.93 (3.03–3.37) times eye length. Spiracles large, crescentic with dorsolateral opening; dorsal margin with a medial protuberance. Nostril narrowly oval to slit-like, directed longitudinally to slightly oblique; lateral margin fleshy; anterior nasal fold internal, very narrow, membranous; broad oronasal groove present; internarial space 1.78 (1.43–1.82) in prenasal length, 2.04 (1.92–2.78) times nostril length. Nasal curtain relatively narrow, skirt-like, short, width 1.54 (1.43–1.86) times length; weakly bilobed, posterior margin of each lobe moderately convex; surface crenulated, weakly papillate, sometimes with weak medial groove and covered with minute pores; apex recessible within lateral margin of oronasal groove; lateral margin almost straight, smooth-edged, usually partly enveloped by narrow posterior fold of nostril; posterior margin strongly fringed, concave medially, vaguely following contour of lower jaw, usually overlapping lower jaw when mouth closed.
Mouth small, jaws strongly asymmetric; lateral grooves shallow, 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 very fleshy, strongly papillate; teeth uniformly close-set in both jaws, in oblique rows, not arranged in obvious quincunx, in paratype CSIRO H 6202-03 rows in upper jaw ~26, lower jaw ~33. 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 male paratype ( CSIRO H 6202-03) with a raised row of greatly enlarged teeth with long caniniform cusps (directed lingually) near the middle of each side of jaw; teeth otherwise small, length of cusps more or less subequal to their base length; teeth at symphysis barely larger than those adjacent, directed lingually, with long acute to bluntly pointed cusps, slightly less oblique than those posterolaterally. Teeth in lower jaw smaller than those of upper jaw, broad based, cusps rather long, 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, forming a weakly fringed lobe laterally; length of first gill slit 1.44 (1.18– 1.32) times length of fifth gill slit, 2.32 (2.14–2.55) times in mouth width; distance between first gill slits 2.62 (2.30–2.44) times internarial space, 0.48 (0.43–0.47) times ventral head length; distance between fifth gill slits 1.45 (1.20–1.41) times internasal distance, 0.26 (0.23–0.25) times ventral head length.
Total pectoral-fin radials 109 (105–110); propterygium 43–44 (43–46), mesopterygium 17–18 (14–19), metapterygium 47–49 (45–49). Pelvic-fin radials: 1 (1) + 21–22 (19–21 in male paratypes, 24–26 in female paratypes). Vertebral centra total (including synarcual) 142 (133–140); total (excluding synarcual) 136 (128–134); monospondylous (including synarcual) 43 (38–41); monospondylous (excluding synarcual) 37 (33–36); pre-sting diplospondylous 74 (64–74); post-sting diplospondylous 25 (18–33).
Squamation. Disc and tail of holotype lacking dermal denticles; a single series of very small, developing thornlets along mid-line of disc on nape in holotype. In larger paratypes ( CSIRO H 6202-04 and CSIRO H 7850- 01) median row on nape well developed and continuous, up to 10 thornlets, last 3 much larger than those preceding; median disc beyond shoulder with a continuous or broken row of smaller seed-shaped thornlets extending to above cloaca; no thornlets on lumbar region or tail; median row on nape much shorter in length than interspiracular width; angle at less than 45° to horizontal (appearing saw-shaped in lateral view); lateral scapular thorns absent.
Evidence of a single caudal sting in all types except one paratype ( CSIRO H 6202-04); stings broken in all cases at their base or removed completely by fishers post capture; distance from cloaca to sting base 0.52 (0.51– 0.56) in disc length.
Colour. Live coloration (based on paratype CSIRO 7850-01). Dorsal surface pale greenish brown centrally and blue-spotted, graduating to more intense reddish brown along margin of disc and pelvic fins; eye whitish, orbital membrane similar to disc. Blue spots small to medium-sized, irregularly spaced, ocellate, with pale blue centres and surrounded by darker blue, diffuse-edged outer rings; distributed mainly over central parts of pectoral fins; largely absent through medial belt; thornlets in medial row white and contrasted with skin; dark speckles distributed randomly on disc; mask-like marking on head rather poorly defined, without dense peppering of speckles. Ventral surface colour based on incomplete image, uniformly white on head. Tail similar to disc colour dorsally before caudal sting, becoming paler greyish white then with black and white bands toward its tip; sides of tail white; dorsal fold similar to dorsal tail; ventral fold dusky with narrow black edge.
In preservative (based on holotype). Dorsal surface dark greyish brown, darker greyish on head and slightly darker across mid-disc and tail; slightly paler around disc submargin (disc edge narrowly blackish; less distinct in paratypes); mask relatively indistinct, with weak peppering of small black spots (similar in paratypes); bluish spots small to medium-sized (in paratypes largest spots 2.7–3.9% DW) appearing as almost entirely greyish markings (not or weakly ocellate); larger spots more variable in paratypes (uniformly coloured to ocellate, in paratype CSIRO H 6124-01 spots distinctly ocellate with pale centres); no blue spots in medial belt (mostly also absent but up to 3 spots in paratypes), when present diameter up to 2.7% DW. Ventral surface of disc and pelvic fins largely white with sharply defined dark greyish brown submarginal bands (less defined in largest paratypes) and narrow black edges; submarginal band broad, at pectoral apex exceeding prenarial length; anterior half of ventral disc with a well-defined, black margin (width ~ 2–3 mm wide). Tail slightly darker dorsally than ventrally; ventral surface forward of ventral fold dark brownish and blotchy; ventral fold uniformly dark (in largest paratypes somewhat darker distally than basally); dorsal fold uniformly dark; banding on post-fold tail primarily black with 4 pale bands (widths and positions of bands variable in paratypes); sting bases greyish white. Clasper dorsal surface slightly paler than dorsal tail; ventral surfaces paler.
Size. Type specimens consist of an adult male of 311 mm DW, two adolescent males of 227 and 295 mm DW, and five females of 247–350 mm DW. White & Dharmadi (2007, as Dasyatis cf. kuhlii Bali form) reported a size at 50% maturity in males of 312 mm DW and a maximum size of females and males of 471 and 450 mm DW, respectively. They also reported that pregnant females contained two pups with a size at birth of 170 mm DW.
Distribution. Type specimens collected from fish landing sites in Bali and southern Central Java in Indonesia ( Fig. 8 View FIGURE 8 ). Fishers catching this species from these landing sites operate in adjacent waters close to port and are not translocated from other areas. Probably not found east of the Wallace Line based on the presence of N. australiae from Lombok, the next island east from Bali, between which the Wallace Line runs. Populations further west in the Indian Ocean are unresolved but are close to this form.
Etymology. Derived from the Latin caeruleus (sky blue) and punctum (dot or spot) with reference to its bluespotted coloration and having a wider distribution than other blue-spotted forms. Vernacular: Bluespotted Maskray.
TABLE 2. Morphometric data for the holotype of Neotrygon caeruleopunctata sp. nov. ( MZB unreg [ex CSIRO H 7852-03]),), with ranges and means provided for measured paratypes, and for the holotype of Neotrygon orientale sp. nov. ( MZB unreg [ex CSIRO H 7858-01]), and ranges and means for the measured paratypes. Measurements expressed as a percentage of disc width.
Holotype Paratypes Holotype Paratypes
Min. Max. Mean Min. Max. Mean
Disc width (mm) 227 247 350 213 171 343 ......continued on the next page
Holotype Paratypes Holotype Paratypes Min. Max. Mean Min. Max. Mean Width 1 st gill slit 3.2 2.8 3.2 3.0 3.0 2.9 3.5 3.2 Width 3rd gill slit 3.4 3.4 3.9 3.5 3.4 3.2 3.6 3.3 Width 5th gill slit 2.2 2.1 2.7 2.4 2.6 2.0 2.3 2.2 Head length 37.2 36.6 38.5 37.4 34.8 35.0 37.4 36.1 Distance between 1 st gill slits 17.7 16.1 17.3 16.7 15.4 15.8 17.0 16.2 Distance between 5th gill slits 9.8 8.4 9.7 9.0 8.7 8.4 9.2 8.9 Cloaca length 5.9 6.3 7.1 6.6 6.6 6.9 7.8 7.3 Clasper postcloacal length 8.7 24.3 24.3 24.3 17.4 20.3 20.3 20.3 Clasper length from pelvic axil 4.5 12.5 12.5 12.5 10.9 13.9 13.9 13.9
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