Neotrygon australiae, 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 : 542-545

Neotrygon australiae sp. nov.

( Figs. 5b , 6b , 7b , 9 ; Table 1)

Neotrygon kuhlii Clade 5— Puckridge et al., 2013: p. 6. Neotrygon kuhlii 4— Naylor et al., 2012: p. 77, fig. 58.

Holotype. CSIRO H 7016-01 (tissue accession BW-A6850), juvenile male 235 mm DW, southwest of Weipa, Gulf of Carpentaria , Queensland, 12°53.96′ S, 141°12.71′ E, 36–38 m depth, 20 Feb 2009 .

Paratypes. 8 specimens: CSIRO CA 3236 , adult male 280 mm DW, north of Port Hedland , Western Australia, 19°28.2′ S, 118°49′ E, 38–46 m depth, 20 Aug 1982 ; CSIRO CA 3247 , adult male 379 mm DW, north of Port Hedland , Western Australia, 19°36′ S, 118°22′ E, 34–36 m depth, 21 Aug 1982 ; CSIRO CA 4307 , female 306 mm DW, northwest Australia ; CSIRO H 3914-01, adult male 287 mm DW, west of Weipa, Gulf of Carpentaria , Queensland, 12°26.9′ S, 141°27.6′ E, 28 m depth, 8 Mar 1995 ; CSIRO H 6144-19 (tissue accession BW-A9396), female 180 mm DW, northwest of Prince of Wales Island, Torres Strait, Queensland, 10°36.68′ S, 141°36.42′ E, 17 m depth, 16 Jan 2004 ; CSIRO H 7017-01 (tissue accession BW-A7794), juvenile male 180 mm DW, north of Mornington Island, Gulf of Carpentaria , Queensland, 16°12.92′ S, 138°58.95′ E, 27–28 m depth, 22 Feb 2009 ; CSIRO H 7018-01 (tissue accession BW-A6849), female 145 mm DW, northwest of Mornington Island, Gulf of Carpentaria , Queensland, 16°19.00′ S, 138°39.53′ E, 23–24 m depth, 23 Feb 2009 ; CSIRO T 693, juvenile male 245 mm DW, north of Wessel Islands , Northern Territory, 9°47′ S, 136°20′ E, 50 m depth, 22 Feb 1982 .

Other material. 12 specimens: CSIRO CA 712 , adolescent male 255 mm DW, Mud Cod Bay , Northern Territory, 14°02′ S, 136°24′ E, Jun 1979 ; CSIRO CA 1241 , female 336 mm DW, north of Admiralty Gulf , Western Australia, 12°53′ S, 125°36′ E, 83–91 m depth, 1 Apr 1981 ; CSIRO CA 3248 , adult male 362 mm DW, northwest of Port Hedland , Western Australia, 20°00.2′ S, 117°55′ E, 34–36 m depth, 22 Aug 1982 ; CSIRO CA 4309 , female 190 mm DW, northwest Australia ; CSIRO H 959-3, juvenile male 191 mm DW, north of Wessel Islands , Northern Territory, 10° S, 137° E, Mar 1987 ; CSIRO H 47-1, female 351 mm DW, north of Wessel Islands , Northern Territory, 9°47′ S, 136°20′ E, 50 m depth, 22 Feb 1982 ; CSIRO H 960-02, female 363 mm DW, probably northern Australia , 22 Mar 1987 ; CSIRO H 5590-01, male 300 mm DW, north of Groote Eylandt , 13°09.8′ S, 136°45.4′ E, 27 m depth, 24 Sep 1998 ; CSIRO T 692, juvenile female 157 mm DW, north of Wessel Islands , Northern Territory, 9°47′ S, 136°20′ E, 50 m depth, 22 Feb 1982 ; CSIRO H 7853-01 (tissue accession BW-A5960), female 255 mm DW, CSIRO H 7853-02 (tissue accession BW-A5961), juvenile male 204 mm DW, Tanjung Luar fish landing site, Lombok , Indonesia, 8°45′ S, 116°35′ E, 25 Oct 2008 ; CSIRO H 7304-07 (tissue accession BW-A10112), adult male 383 mm DW, CSIRO H 7304-08 (tissue accession BW-A10113), 318 mm DW, CSIRO H 7304-09 (tissue accession BW-A10114), 305 mm DW, Tanjung Luar fish landing site, Lombok , Indonesia, 8°45′ S, 116°35′ E, 4 Aug 2010 ; CSIRO H 7217-05 (tissue accession BW-A11341), 290 mm DW, CSIRO H 7217-06 (tissue accession BW-A11342), 286 mm DW, Tanjung Luar fish landing site, Lombok , Indonesia, 8°45′ S, 116°35′ E, 24 Jan 2011 ; KFRS unreg (field code 220341), adult male 301 mm DW, KFRS unreg (field code 220342), adult male 301 mm DW, Daru fish market, Western Province, Papua New Guinea, 9°03.91′ S, 143°12.59′ E, 22 Oct 2014 ; MNHN A7931 (syntype of N. kuhlii ), late-term embryo, male 99.7 mm DW, West Papua, New Guinea, 7°30′ S, 132°30′ E, 1827.

Diagnosis. A large Neotrygon of the kuhlii -complex (reaching at least 45 cm DW; males maturing at ~ 28 cm DW) with the following combination of characters: disc much broader than long, width 1.2–1.3 times length; pectoral apices narrowly angular; snout fleshy, broadly rounded to weakly angular, angle 101–103°, length 1.6–2.1 times interorbital width; maximum width relatively well back on disc, length from snout tip to pectoral-fin insertion 1.7–1.8 times and disc width 2.3–2.5 times horizontal distance from snout tip to maximum disc width; preoral length 1.8–2.3 times mouth width; internasal distance 1.3–1.6 in prenasal length; interspiracular distance 14–16% DW; nostril length 3.4–4% DW; nasal curtain width 8.4–9.1% DW; small mouth, width 6.5–7.3% DW; horizontal distance from cloaca to caudal sting base 42–52% 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 105–113; total vertebral centra (including synarcual) 129–134, trunk centra (including synarcual) 37–41; blue spots large, largest spot on disc 0.7–1.2 times eye width; 2–17 (mean 9.4) blue spots on medial belt, largest 3.3–5.6% DW; mask-like marking subtle, usually lightly covered with dark peppery spots (dark spots not widespread over central disc); ventral surface of disc with distinct dark greyish brown submarginal bands; ventral tail fold almost entirely dark.

Description. Disc quadrangular, straight to weakly convex anteriorly and not produced; much broader than long, width 1.21 times length in holotype (1.17–1.25 in paratypes); snout angle 103° (101–103°); axis of greatest width of disc relatively well back on disc, almost over scapular region, its distance from snout tip 1.78 (1.67–1.77) times in distance from tip of snout to pectoral-fin insertion; body relatively robust, thickness 7.9 (7.0–8.5) times in disc width, raised slightly above cranium; apex broadly rounded, narrowly or abruptly angular, pectoral angle 87° (84–89°); posterior margin straight to weakly convex; 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 19.3% (18.4–22.3%) DW; 1.25 (1.14–1.34) times width across fin bases. Claspers of adult males large, depressed, tapering, acutely pointed apically; outer length (from axil of pelvic fin) 18.0% DW.

Tail moderately broad-based, tapering rapidly to caudal stings, with dorsal and ventral skin folds; base moderately depressed, broadly oval in cross-section, weakly convex above and below, width 1.40 (1.33–1.63) times depth; subcircular to rhomboidal in cross-section near origin of ventral skin fold, width 1.06 (0.95–1.22) times height at fold origin; tapering evenly in dorsoventral view posterior to caudal stings; moderately compressed at end of caudal stings; damaged distally beyond folds in one large paratype; both dorsal and ventral skin folds prominent; tail very compressed, narrowly suboval in cross-section above mid ventral fold, width 0.55 (0.52–0.66) times depth; at end of fold weakly depressed, width 1.00 (0.52–0.93) times height; dorsal surface of tail posterior to caudal-sting bases with a weak naked groove (partly housing ventral-most sting and extending for about half to its full length); no skin folds present along lateral margin of tail. Dorsal skin fold well developed, short-based, pronounced, length about 10 (7–19) times its height, 1.31 (1.03–1.46) in snout length, 6.34 (4.00–6.61) in length of ventral fold; its height 1.09 (0.74–1.53) in height of mid-ventral fold; origin sometimes coincident with apex of second sting, sometimes with a short low ridge before elevated portion; elevated portion slightly less than or equal to snout length. Ventral skin fold relatively long, 68.2 (50.1–68.3)% DW, relatively narrow, tapering, deepest forward of dorsal skin fold; much longer based and distinctly taller than dorsal skin fold; length 1.47 (1.46–1.99) in disc width; depth at quarter length 0.78 (0.37–0.67), at mid length 0.72 (0.52–0.63), at three quarter 0.86 (0.40– 0.85) in adjacent tail height; originating almost below or just forward of first sting origin; horizontal distance from cloaca to sting origin 1.91 (1.61–1.97) in precloacal length.

Snout fleshy (more so in large paratypes), short, broadly rounded; not acute at apex, but without obvious apical lobe; angle 103° (101–103°); narrowly rounded when viewed laterally, becoming slightly more depressed towards apex; preoral snout length 1.82 (1.89–2.31) times mouth width, 1.77 (1.74–2.11) times internarial distance, 0.78 (0.79–0.91) times distance between first gill slits; direct preorbital snout length rather short, 1.63 (1.63–2.09) times interorbital length; snout to maximum disc width 2.48 (2.30–2.54) in DW; interorbital space narrow, weakly concave (almost straight in some paratypes); eyes large, dorsolateral, strongly protruding, ventral margin partly covered by thick skin fold; orbit greatly elevated above disc and interorbital space, diameter 0.92 (0.76–0.93) in spiracle length, eye length 1.19 (1.13–1.41) in spiracle length; inter-eye distance 2.94 (2.59–3.07) 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 1.36 (1.26–1.56) in prenasal length, 1.88 (1.78–2.28) times nostril length. Nasal curtain relatively narrow, skirt-like, short, width 1.50 (1.45–1.72) times length; weakly bilobed, posterior margin of each lobe moderately convex; surface crenulated, 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 in holotype and most paratypes.

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 T 693 rows in upper jaw ~24, lower jaw ~31. 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 juvenile male syntype ( CSIRO T 693) with a raised row of greatly enlarged teeth with long caniniform cusps (directed lingually) near the middle of each side of jaw; teeth otherwise similar in shape, cusps more or less subequal to their base length; those at symphysis barely larger than those adjacent. Teeth in lower jaw smaller than those of upper jaw, broad based, low, with semi-truncate to slightly concave distal margins, those toward angle of lower jaw with slightly shorter cusps; no rows of enlarged teeth in jaw. 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 1.09 (1.14– 1.59) times length of fifth gill slit, 2.39 (1.88–2.40) times in mouth width; distance between first gill slits 2.26 (2.12–2.54) times internarial space, 0.45 (0.43–0.46) times ventral head length; distance between fifth gill slits 1.17 (1.14–1.35) times internasal distance, 0.23 (0.22–0.26) times ventral head length.

Total pectoral-fin radials 112–113 (105–111); propterygium 44 (42–45), mesopterygium 17 (14–19), metapterygium 51–52 (46–49). Pelvic-fin radials: 1 (1) + 18–19 (18–19 in male paratypes, 23 in female paratype). Vertebral centra total (including synarcual) 132 (129–134); total (excluding synarcual) 129 (123–130); monospondylous (including synarcual) 37 (39–41); monospondylous (excluding synarcual) 34 (34–36); pre-sting diplospondylous 76 (66–71); post-sting diplospondylous 19 (17–25).

Squamation. Disc and tail of holotype lacking dermal denticles; a single series of variable-length, narrow, spear-shaped to narrow lanceolate thornlets along mid-line of disc on nape; median row continuous on nape, with 11 (8–13) thornlets when developed, anteriormost thornlets smallest; row length slightly shorter than or equal to interspiracular width; two largest thornlets larger than those adjacent, angle at less than 45° to horizontal (appearing saw-shaped in lateral view); no thornlets on lumbar region or tail; lateral scapular thorns absent. In largest paratypes ( CSIRO CA 3236, CSIRO CA 3247 and CSIRO CA 4307), row of thornlets on nape almost connected with a well-developed lumbar row; lumbar series weakly developed in CSIRO H 3914-01; nape and lumbar series both absent in smallest paratypes ( CSIRO H 7017-01 and CSIRO H 7018-01).

Two caudal stings in holotype (1 or 2 in paratypes), intact, second much longer than first; caudal stings very elongate, slender, narrow based, longest sting exceeding preorbital length; enveloping membrane absent; distance from sting base to pectoral-fin insertion 36.9% (32.6–40.3%) DW, 4.02 (1.78–2.44) times first sting length; distance from cloaca to sting base 0.45 (0.42–0.52) in disc length.

Colour. Live coloration (based on holotype). Dorsal surface pale yellowish brown and blue-spotted, barely graduating to slightly paler yellowish pink along margin of disc and pelvic fins; eye dark, orbital membrane darker than disc. Blue spots large, irregularly spaced, ocellate, with pale bluish white centres and surrounded by thick, diffuse-edged darker grey blue outer rings; distributed widely over disc; well represented on medial belt; thornlets in medial row white and contrasted with skin; mask-like marking on head distinct, medium brown with whitish blotch on posterior edge; dark speckles most concentrated on mask and comparatively sparse elsewhere. Ventral surface uniformly white centrally on disc, submarginal band greyish and distinct. Tail slightly darker than disc dorsally before caudal sting, becoming even darker then with black and white bands toward its tip; sides of tail dusky; dorsal and ventral folds blackish.

In preservative (based on holotype). Dorsal surface pale yellowish, darker greyish on head and across mid-disc and tail; palest around disc submargin (disc edge blackish); mask and orbital membranes dark, with a moderate peppering of small black spots; bluish spots large (in paratypes largest spots 4–6.2% DW), appearing as greyish blue markings with pale centres (somewhat ocellate). Ventral surface of disc and pelvic fins almost uniformly white with narrow black edge; submarginal bands barely detectable, weak and diffuse-edged in smallest paratypes. Tail darker dorsally than ventrally; ventral surface forward of ventral fold pale to faintly dusky (slightly darker in some paratypes, but noticeably paler than dorsal surface); ventral fold dark with a very narrow pale base; dorsal fold uniformly dark; banding on post-fold tail primarily black with three narrow, pale bands (banding on paratypes variable); stings greyish white. Claspers distinctly paler than dorsal tail, similar on dorsal and ventral surfaces.

Size. Type specimens consisted of three adult males of 280–379 mm DW, three juvenile males of 180–245 mm DW, and three females of 145–306 mm DW. Other material examined includes and adult male of 383 mm DW, an adolescent male of 255 mm DW and a female of 351 mm DW. Specimens observed at the Tanjung Luar fishing port in Lombok (from local catches) included females of up to 452 mm DW and adult males up to 410 mm DW.

Distribution. Type specimens were collected from northern Australia, from off Port Hedland, east to northeastern Gulf of Carpentaria ( Fig. 8 ) at depths of 23– 50 m. Other specimens taken from off Daru (northern Torres Strait Islands) in Papua New Guinea and Lombok in Indonesia. Found over and adjacent to rocky and coral reefs from shallow water to at least 91 m depth. Specimens recorded off eastern Queensland to northern New South Wales are referrable to Neotrygon trigonoides and it is possible N. australiae does not overlap but additional research is required. The extent of the range of this species in New Guinea needs more research.

Etymology. Epithet demarcates the Australasian distribution of this member of bluespotted mask ray complex of the genus Neotrygon . Vernacular: Australian 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 9. Holotype of Neotrygon australiae sp. nov. (CSIRO 7016 - 01, juvenile male 235 mm DW) from Queensland, Australia (fresh): (A) dorsal view; (B) ventral view.