Maculabatis bineeshi, Manjaji-Matsumoto, B. Mabel & Last, Peter R., 2016

Manjaji-Matsumoto, B. Mabel & Last, Peter R., 2016, Two new whiprays, Maculabatis arabica sp. nov. and M. bineeshi sp. nov. (Myliobatiformes: Dasyatidae), from the northern Indian Ocean, Zootaxa 4144 (3), pp. 335-353 : 344-352

Maculabatis bineeshi sp. nov.

( Figs. 7–14 ; Table 1)

Dasyatis uarnak (not Forsskål): Jones & Kumaran, 1970, fig. 16, two specimens 425 and 480 mm DW (compiled distribution partly in error).

? Himantura gerrardi (not Gray): Ishihara et al. 1998, 44, pl. 3, brief description of two specimens, MTUF 30005 figured (misidentification, in part).

Himantura sp. D: Manjaji, 2004, 5.152–159, figs (thesis).

Himantura sp. 3: Last et al., 2016 (molecular tree, fig. 3).

Maculabatis sp. 3: Last et al., 2016 (molecular tree, fig. 5).

Holotype. LACM 38131-43 , immature male 241 mm DW, 6–8 km south of Hajambro Creek , Sind, Pakistan, Arabian Sea, near coast, 25 April 1978.

Paratypes. 4 specimens. CSIRO H 7998-01 (formerly part of LACM 38130-47 ), female 250 mm DW, off Hajambro Creek , Sind, Pakistan, 13–22 m, 25 April 1978 ; LACM 38130-47 (2 specimens), immature male 241 mm DW, immature male 198 mm DW, collected with specimen above; LACM 38133-75 , female 248 mm DW, off Turshian Creek , Sind, Pakistan, Arabian Sea, 15–29 m, 26 Apr 1978 .

Other material. 8 specimens (Cestode database, http://tapewormdb.uconn.edu/). Photographic images (IN-35, IN-36, IN-52, IN-55) and tissues only, DNA reference codes GN 13965, 13966, 13968, 13981, 13982, 13998, 14001, 14006, 222– 660 mm DW, Odisha, India, Bay of Bengal, June 2013.

Diagnosis. A species of Maculabatis (to at least 66 cm DW) distinguished by a combination of the following characters: disc weakly rhomboidal to suboval, length 93–98% DW; snout moderately elongate with weak apical lobe, snout angle 116–121°; pectoral-fin apices broadly rounded; orbits small to medium-sized, barely protruding; mouth relatively narrow, width 1.2–1.3 in internasal width; distance between first gill slits 2.2–2.5 times internasal distance; distance between fifth gill slits 1.4–1.6 times internasal distance, 28–30% of ventral head length; pelvicfin base broad, 14–15% DW; main suprascapular denticle large, yellowish, broadly ovate, usually followed by smaller subtriangular denticle; secondary denticles developing rapidly, forming broad band extending from interorbit to tail base by 24 cm DW; dorsal disc uniformly light brown, without white spots; pale ventrally with broad, faint and slightly darker lateral margins; tail dark brown to blackish dorsally and white ventrally forward of caudal sting; plain blackish posteriorly or with weak, irregular pale dorsal banding (in young); pectoral-fin radials 127–131; total vertebral count, including synarcual centra 108–114, monospondylous centra 44–46, pre-sting diplospondylous centra 64–69.

Description. Disc weakly rhomboidal to suboval, width 1.07 in holotype (1.02–1.08 in paratypes) times length; robust, strongly raised in midscapular region, maximum thickness 0.12 (0.11–0.13) in DW; snout with a weak apical lobe, angle 121 0 (116–121 0); anterior disc margin almost straight, lateral apices broadly rounded, posterior margin broadly convex, free rear tip relatively broadly rounded. Pelvic fins moderately small, 18.6% (18.4–19.7%) DW; width across base 14.7% (14.3–15.0%) DW; largely concealed by disc. Mature male specimens unavailable for examination of clasper structure. Tail slender and whip-like, tapering gently and evenly toward caudal sting and beyond, length 2.44 (2.43–2.55) times DW; base depressed oval in cross-section, width 1.58 (1.49–1.87) times height at base.

Snout moderately elongate, depressed; preoral length 3.05 (2.88–3.10) times mouth width, 2.31 (2.24–2.60) times internarial distance, 21.4% (20.5–23.3%) DW; direct snout length 1.60 (1.62–1.75) times interorbital length, distance from snout tip to axis of maximum disc width 42% (39–41%) DW; interorbital space flat to weakly convex; eye moderately large, diameter 1.52 (1.62–2.32) in spiracle length; orbits very slightly protruded, diameter 0.85 (0.92–1.14) in spiracle length, interorbital distance 1.87 (1.82–2.23) times orbit. Spiracles subrectangular, large, situated dorsolaterally. Nostrils moderately large, slit-like, oblique; outer margin weakly double concave, length 2.01 (2.09–2.21) in internasal distance; internasal distance 1.73 (1.72–1.92) in prenasal length. Nasal curtain skirt-shaped (diverging slightly posteriorly), relatively broad, width 1.60 (1.70–1.98) times length; lateral margin straight, smooth edged; posterolateral corner lobe-like, recessible within broad groove; posterior margin very finely fringed, concave. Mouth arched weakly to prominently, oronasal groove prominent; skin on ventral surface of lower jaw moderately well-corrugated, confined to narrow strip around lips. Mouth with 4 well-developed oral papillae; medial pair simple, rounded distally, longitudinally flattened, sub-equal in size and much larger than outer pair; medial papillae much closer to each other than to outer papilla; outer papillae located at each corner of mouth. Teeth small, subequal in upper and lower jaws; cone-shaped with blunt peaks, with prominent horizontal groove. Gill opening margins smooth, straight; length of first gill slit 1.49 (1.47–1.53) times length of fifth, 2.39 (2.19– 2.56) in mouth width; distance between first gill slits 2.23 (2.23–2.50) times internasal distance, 0.46 (0.43–0.48) of ventral head length; distance between fifth gill slits 1.41 (1.45–1.56) times internasal distance, 0.29 (0.28–0.30) of ventral head length.

Squamation. Ontogenetic stages with size ranges broadly overlapping; rate of denticle development rapid, secondary denticle band well-developed by 240 mm DW. Stages 3, 5 and 6 not applicable for this species. Single elongate caudal sting present in all types.

Stages 0–1: from birth (probably ~ 150–170 mm DW), no representative specimens available for study, but disc of newborns most likely entirely smooth or with 1–3 suprascapular denticles, and possibly a median primary denticle series that become inconspicuous with age.

Stage 2: ~ 190–250 mm DW, initial stage for development of secondary denticle band; smallest specimen (LACM 38130-47(2 of 3), 198 mm DW) with marginal denticles of scapular region still embedded within skin; minute spinulose denticles developing on dorsal surface of tail beyond caudal sting. Primary denticle band inconspicuous. Main suprascapular denticle large, yellowish and broadly ovate (3.6–4.7 mm in length); usually followed (and occasionally preceded) by smaller subtriangular denticle (distinctly larger than surrounding secondary denticles).

Stage 4:> 240 mm DW, secondary denticle band with sharply-defined margin; band continuous along trunk from interorbital region almost to pectoral-fin insertion (LACM 38130-47(1 of 3), 241 mm DW). In another slightly larger paratype (LACM 38133-75, 248 mm DW), denticle band extends forward onto preorbital region. In larger specimens (e.g. non-types IN-35 390 mm DW), band extends across mid-dorsal surface well onto tail before caudal sting; anterior margin extending well forward of orbits (naked part of snout ~63% snout length). In largest available specimen, an adult male (IN- 55, 660 mm DW), denticle band very broad (width at level of spiracles exceeding twice interspiracular width); its anterior margin broadly rounded, convex beside eyes, converging slightly posteriorly, almost truncate at pectoral-fin insertion. Skin outside denticle band, skin smooth, without denticles. Denticles in band, closely set; subequal in size, only slightly smaller along margins than at mid-disc.

Meristics. Total pectoral-fin radial counts (for types, n=5) 130–131 (127–131); propterygium 50–52 (50–52), mesopterygium 19–20 (17–21), metapterygium 60 (57–61). Pelvic-fin radials 25–26 (23–30). Vertebral centra (including synarcual) 112 (108–114); monospondylous 46 (44–45), pre-sting diplospondylous 65 (64–69); and post-sting diplospondylous 0.

Colour. Holotype (preserved): Disc uniform medium brown, plain without any white spots; ventral surface uniformly pale brown (probably artefactual from preservation) with faint, slightly darker yellowish brown margins; marginal markings beginning near lateral apices of pectorals, continuing to posterior tip of pectorals, and including posterior margins of pelvic fins. Tail dark brownish to blackish dorsally and pale ventrally forward of caudal sting; white spots on dorsolateral margin very few or more typically absent; white banding behind sting inconspicuous, very weak (narrow and irregular) or absent even in juveniles, width of black bands 2–7 times width of white (pale) bands; ventral tail beyond caudal sting plain dark greyish to black.

Fresh images of non-types. IN-52 (GN 13998), immature male 222 mm DW: Dorsal disc plain dark greenish brown, slightly paler towards outer disc margins; dorsal tail greenish brown to caudal sting, then becoming dark greyish or black with a few, narrow and irregularly spaced white bands anteriorly; ventral disc white with narrow, sharply defined greyish brown margins extending from forward of pectoral-fin apices to its insertions, symmetric patch of irregular submarginal blotches beside mid-anterior margins; ventral tail white forward of caudal sting, then becoming dark greyish to black distally. IN-35 (GN 13981), female 390 mm DW: Dorsal disc and tail base greenish brown, reddish along outer disc margin (probably due to damage); posterior tail darker greyish but without distinct bands; ventral surface of disc whitish with dusky (or bluish) outer margins, no patches of darker blotches beside anterior margins; ventral tail white forward of caudal sting, then becoming dark greyish to black distally, possibly weakly blotched medially. IN-55 (GN 14001), adult male 660 mm DW: Dorsal disc and tail brownish, tail beyond caudal sting weakly mottled brown and white; clasper blackish apically; ventral surface white with prominent, narrow, greyish brown marginal band (its mesial edge sharply defined), patches of dark blotches present beside anterior margins; ventral tail faintly mottled brown and white (much paler than smaller specimen above).

Size. Types based on immature individuals. Largest specimen, an adult male, was 66 cm DW and ~ 2 m TL (IN-55, Caira & Jensen, 2013). The claspers of the next largest known male (IN-36, 51 cm DW) were not expanded. Smallest specimen (LACM 38130-47 (2 of 3), immature male 20 cm DW) is postnatal; birth size unknown, probably ~ 150–170 mm DW.

Distribution. Pakistan and off India, in the western Bay of Bengal; probably more widely distributed between but its occurrence may be strongly habitat dependent. In Pakistan, off Sind, south of Karachi, from coastal waters to offshore in 2–22 m depth. Bay of Bengal, off Odisha (Talasari to Digha). Possibly in West Bengal Province, in Diamond Harbour and as far north in Farakka, India ( Ishihara et al., 1998).

Etymology. Patronym recognising the research efforts of Indian biologist K.K. Bineesh, who has worked closely with local Indian colleagues to build a better understanding of the shark and ray fauna of the northern Indian Ocean. Vernacular: Short-tail Whipray ( Manjaji, 2004).

Remarks. The five type specimens of Maculabatis bineeshi sp. nov., all collected from Pakistan (Sind and near Karachi), were previously identified as M. gerrardi (as Himantura gerrardi ). The only images available to us of fresh material of M. bineeshi were obtained through a global assessment of cestode parasites of elasmobranchs, led by Janine Caira and Kirsten Jensen. None of these specimens was retained, but images of them provide important information on coloration and denticle band development in the host species.

Other specimens, tentatively assigned to this taxon by Manjaji (2004) from India and Bangladesh, MTUF 3000 (Farakka, India) and CAS 141048 (Megna River, Bangladesh), need further investigation as they may be other species of Maculabatis . Both specimens have a blackish tail with weak alternating bands, and a slight marbled appearance behind the caudal sting, especially on the ventral surface. The Indian specimen, figured by Ishihara et.al. (1998) with disc width given as 676 mm (subsequently remeasured by MM as 421 mm DW), resembles a large M. pastinacoides , except for its shorter and weakly banded tail (not banded in M. pastinacoides ); morphometric and meristic data for M. bineeshi and M. pastinacoides overlap slightly.

Comparisons. Maculabatis arabica sp. nov. belongs to a subgroup of plain-coloured species consisting of M. pastinacoides ( Bleeker, 1852) from the Indo–Malay region, and M. randalli (Last, Manjaji-Matsumoto & Moore) and M. bineeshi sp. nov. from the Indian Ocean. It is also sympatric in the Arabian Sea with a more common, white-spotted species Maculabatis gerrardi ( Gray, 1851) . Molecular data suggests that M. arabica is most closely related to M. randalli with which it is also sympatric in the Arabian Sea ( Last et al., 2016). Based on data available, Maculabatis arabica is distinguishable from other plain-coloured Indian Ocean species by a combination of characters, i.e. disc more distinctly broader than long (width 1.08–1.13 vs. 1.02–1.08 times length in both M. randalli and M. bineeshi ), interorbital space narrower (width 11.2–12.1% DW vs. 12.8–15.0% DW in M. randalli and 12.6–13.8% DW in M. bineeshi ), interspiracular space narrower (width 16.4–18.0% DW vs. 17.5–18.9% DW in M. randalli and 18.8–19.2% DW in M. bineeshi ), tail base more depressed (height 4.0–4.5% DW vs. 4.4–5.5% DW in M. randalli and 4.4–5.3% DW in M. bineeshi ), precloacal length typically shorter (length 73–77% DW vs. 77–82% DW in M. randalli and 76–82% DW in M. bineeshi ) and pelvic-fin base narrower (length 11.7–12.8% DW vs. 13.3–16.8% DW in M. randalli and 14.3–15.0% DW in M. bineeshi ). Compared to M. bineeshi , mid-scapular denticles of M. arabica are smaller seed to heart-shaped (larger and ovate and triangular), the rate of denticle development of the dorsal band is slower (similar to M. gerrardi ), denticles in the band are smaller, and the tail is more prominently banded (especially so in juveniles but less so with increasing size) rather than weakly banded dorsally (dark bands 2–7 times wider than white rings) with an almost entirely black rear portion in M. bineeshi . Other morphometric differences between M. arabica and M. randalli include a relatively longer total length (when tail undamaged) in M. arabica (length 3–3.4 times DW vs. 2.5–3.2% DW), shorter prenasal length (15.7–16.5% DW vs. 16.5–17.4% DW), broader internasal width (8.4–8.9% DW vs. 7.9–8.1% DW) and narrower interspace between the 1st gill slits (width 18.9–19.9% DW vs. 19.9–21.3% DW).

Differences between M. arabica and M. bineeshi include a marginally shorter disc in M. arabica (length 89– 93% DW vs. 93–98% DW), narrower tail at base of caudal sting (width 2.1–2.4% DW vs. 2.6–2.8% DW), narrower nasal curtain (width 9.5–10.7% DW vs. 10.7–11.2% DW), and narrower interspace between the 1st gill slits (width 18.9–19.9% DW vs. 20.3–21.9% DW).

Additional differences between M. bineeshi and M. randalli include a larger orbit in M. bineeshi (length 6.2– 6.9% DW vs. 4.6–5.7% DW), broader tail base (width 7.0–8.8% DW vs. 5.9–6.9% DW), and broader internasal space (width 8.8–9.4% DW vs. 7.9–8.1% DW).

The two new species described here differ other than in morphometrics. Maculabatis bineeshi has a longer and more broadly rounded disc than M. arabica , midscapular denticles differ in shape and are associated with a more rapid denticle band development, the posterior tail is darker and feebly banded even in juveniles (vs. strongly banded in juveniles but bands indiscernible in adults), and M. bineeshi has marginally more vertebrae (centra including synarcual 108–114 vs. 102–111).

Comparative material. Maculabatis randalli : CSIRO H 7254–01, adult male 412 mm DW, Persian Gulf, Kuwait (holotype) ; BPBM 33201 (2 specimens), female 151 mm DW, female 245 mm DW, Persian Gulf , Kuwait (paratypes) ; BPBM 29480 , early adolescent male 325 mm DW, Persian Gulf , Bahrain ; MTUF 20642 , female 414 mm DW, Persian Gulf (paratype) ; CSIRO H 7296–01, female 251 mm DW, Persian Gulf , Kuwait (paratype) .

Figures

FIGURE 7. Holotype of Maculabatis bineeshi sp. nov., juvenile male 241 mm DW (LACM 38131 - 43, preserved), from Karachi, Pakistan: (A) Dorsal view; (B) Ventral view.

FIGURE 8. Fresh coloration of non-type of Maculabatis bineeshi sp. nov., small juvenile male 222 mm DW (IN- 52, not retained), from Odisha, India, Bay of Bengal: (A) Dorsal view; (B) Ventral view.

FIGURE 9. Fresh dorsal coloration of non-types of Maculabatis bineeshi sp. nov. from Odisha, India, Bay of Bengal: (A) immature female 390 mm DW (IN- 35, not retained); (B) adult male 660 mm DW (IN- 55, not retained).

FIGURE 10. Oronasal region the holotype of Maculabatis bineeshi sp. nov., juvenile male 241 mm DW (LACM 38131 - 43, preserved), from Karachi, Pakistan.

FIGURE 11. Squamation of the mid-disc of the holotype of Maculabatis bineeshi sp. nov., juvenile male 241 mm DW (LACM 38131 - 43, preserved), from Karachi, Pakistan.

FIGURE 12. Lateral view of tail (at caudal sting) of the holotype of Maculabatis bineeshi sp. nov., juvenile male 241 mm DW (LACM 38131 - 43, preserved), from Karachi, Pakistan.

FIGURE 13. Post caudal-sting tail the holotype of Maculabatis bineeshi sp. nov., juvenile male 241 mm DW (LACM 38131 - 43, preserved), from Karachi, Pakistan. A. Dorsal view; B. Lateral view; C. Ventral view.

FIGURE 14. Map showing specimen locations of Maculabatis arabica sp. nov. (red) and Maculabatis bineeshi sp. nov. (yellow). Stars denote primary types (holotypes), solid circles secondary types and non-type material.