Maculabatis arabica, 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 : 337-344

Maculabatis arabica sp. nov.

( Figs. 1 –6,14; Table 1)

Himantura sp. C: Manjaji, 2004, 5.145–151, figs.

Himantura sp.: Henderson et al., 2016 (molecular tree, fig. 4). Himantura sp. 2: Last et al., 2016 (molecular tree, fig. 3). Maculabatis sp. 2: Last et al., 2016 (molecular tree, fig. 5).

Holotype. LACM 38133-74 , female 325 mm DW, 3–4 km west of Turshian Creek , Sind, Pakistan, Arabian Sea, 2405' N, 6736' E, 15–29 m, 26 Apr 1978.

Paratypes. 12 specimens. BPBM 27511 , adult male 438 mm DW, Cochin fish landing, India, 30 January 1980 ; CSIRO H 7997-01 (formerly part of LACM 38318-11 ), female 251 mm DW, Baluchistan, Pakistan, 22–27 m, 4 Feb 1979 ; LACM 38311-34 , immature male 234 mm DW, Sonmiani Bay , Baluchistan, Pakistan, 22–27 m, 4 Feb 1979 ; LACM 38312-27 , immature male 251 mm DW, Sonmiani Bay , Baluchistan, Pakistan, 26–37 m, 5 Feb 1979 ; LACM 38318-11 , immature male 268 mm DW, Baluchistan, Pakistan, 22–27 m, 4 Feb 1979 ; USNM 216232 , female 433 mm DW, Gujarat, India, Arabian Sea , 2254' N, 6836' E, 19 Nov 1963 ; USNM 216235 , female 500 mm DW, Gujarat, India, Arabian Sea , 2300' N, 6810' E, 19 Nov 1963 ; USNM 216238 , female 634 mm DW, Gujarat, India, Arabian Sea , 2300' N, 6810' E, 19 Nov 1963 ; USNM 216239 , female 360 mm DW, Gujarat, India, Arabian Sea , 2316' N, 6750' E, 19 Nov 1963 ; USNM 216246 , adult male 450 mm DW, Pakistan, Arabian Sea , 2457' N, 6556' E, 7 Dec 1963 ; USNM 216247 , immature male 360 mm DW, Pakistan, Arabian Sea , 2457' N, 6556' E, 7 Dec 1963 ; USNM 216248 , female 285 mm DW, Pakistan, Arabian Sea , 2457' N, 6556' E, 7 Dec 1963 .

Other material. One specimen. CAS 29630, female 173 mm DW, off Karachi , Pakistan, Arabian Sea, 23 Oct 1973.

Diagnosis. A species of Maculabatis (to at least 63 cm DW) distinguished by a combination of the following characters: disc broadly rhomboidal, length 89–93% DW; snout moderately elongate with small apical lobe, snout angle 113–121°; pectoral-fin apices narrowly rounded; orbits small, protruding slightly; mouth relatively narrow, width 1.1–1.6 in internasal width; distance between first gill slits 2.1–2.3 times internasal distance; distance between fifth gill slits 1.4–1.5 times internasal distance, 28–30% of ventral head length; pelvic-fin base narrow, 12–13% DW; small yellow, seed-shaped suprascapular denticle followed by a slightly larger white, heart-shaped denticle; weak primary denticle band present in young but soon becoming inconspicuous; secondary denticle band irregularly suboval, relatively narrow with well-defined lateral margins, rounded forward of orbit and not extending lateral to orbit even in large adults; band broad near tail base in adults; dorsal disc uniformly brownish (lacking white spots); ventral disc pale with broad, weakly-defined and slightly darker margins; anterior tail lightbrown on dorsal surface and usually without white lateral spots; tail banded dorsally behind caudal-sting base, bands more obscure or absent with age; pectoral-fin radials 127–135; total vertebral count, including synarcual centra 102–111, monospondylous centra 41–47, pre-sting diplospondylous centra 55–68.

Description. Disc rhomboidal, width 1.11 in holotype (1.08–1.13 in paratypes) times length; moderately well raised in scapular region, maximum disc thickness 0.12 (0.09–0.14) in DW; pointed apical lobe of snout relatively narrow and distinct, angle 121 (113–118); anterior margins of disc undulate, lateral apices narrowly rounded, posterior margin broadly convex, free rear tip narrowly rounded. Pelvic fins moderately small, length 18.5% (18.6– 20.2%) DW, width across base 12.8% (11.7–12.5)% DW; largely concealed by disc. Mature male specimen unavailable for examination of clasper structure. Tail slender and whip-like, tapering weakly and evenly towards caudal sting and tail tip; base suboval, base slightly depressed in cross-section, width 1.45 (1.56–1.70) times height; subcircular below caudal sting; somewhat depressed towards apex; tip damaged in holotype, length 2.23– 2.62 times DW in paratypes.

Snout moderately elongate, depressed; preoral length 3.06 (2.75–3.61) times mouth width, 2.52 (2.31–2.44) times internarial distance, 21.2% (20.5–22.0%) DW; direct snout length 1.76 (1.75–1.83) times interorbital length; distance from snout tip to axis of maximum disc width 42% (41–43%) DW; interorbital space flat; eye lateral, moderately large, diameter 2.16 (1.78–2.22) in spiracle length; orbits protruded slightly, diameter 1.35 (0.98–1.26) in spiracle length, interorbital distance 2.23 (1.72–2.05) times orbit diameter. Spiracles subrectangular, large, situated dorsolaterally. Nostrils moderately elongate, slit-like, slightly oblique; outer margin with a weak double concavity, length 1.82 (1.90–2.14) in internasal distance; internasal distance 1.88 (1.74–1.87) of prenasal length. Nasal curtain skirt-shaped, relatively narrow, width 1.62 (1.60–1.79) times length; lateral margin almost straight, smooth edged; posterolateral apex lying within broad groove; posterior margin very finely fringed, weakly double concave. Mouth well arched, oronasal groove prominent; skin on ventral surface of lower jaw well corrugated, confined to narrow strip around lower lip. Mouth floor with 2–4 papillae; medial pair simple, rounded distally, subequal in size (almost three times larger than outer pair), located close to each other; outer pair located at each corner of mouth when present, widely separated from inner pair. Teeth small, subequal in size in upper and lower jaws; cone-shaped with blunt peaks and prominent horizontal groove. Gill slit margins smooth, straight; length of first gill slit 1.61 (1.41–1.90) times length of fifth, 2.11 (1.83–2.33) in mouth width; distance between first gill slits 2.25 (2.12–2.27) times internasal distance, 0.43 (0.42–0.44) of ventral head length; distance between fifth gill slits 1.48 (1.38–1.46) times internasal distance, 0.28 (0.28–0.30) in ventral head length.

Squamation. Ontogenetic stages 0, 1, 2 and 4 present; stages 3, 5 and 6 not applicable. Denticle development stages with size overlap; secondary denticle band on dorsal surface of disc developing relatively slowly, possibly faster in females than males.

Stage 0: Disc entirely smooth at birth (probably <170 mm DW), or with one, small yellowish seed-shaped suprascapular denticle in early postnatal juveniles (CAS 29630, 173 mm DW).

Stage 1: ~ 230–270 mm DW, 1–2 additional, white, heart-shaped suprascapular denticle(s) just posterior to seed-shaped denticle (first usually larger than heart-shaped denticle); much smaller seed-shaped and narrow heartshaped primary denticles forming a linear extension anteriorly, arranged in a narrow series (1–2 rows) along most of nuchal region. Band becoming obscure with age.

Stage 2: ~ 250–325 mm DW, initial stages of development of secondary denticle band; onset laterally around primary band on mid-disc, followed by development of cranial patch; margins of band weakly-defined, some denticles embedded beneath skin. Denticles in band compact, close-set, small- and large-sized denticles interspersed (length of larger denticles 1.3-1.5 mm); uniform in size along margins. During mid-stage, sparse spinulose (minute cone-shaped) denticles develop along dorsal surface on posterior half of tail.

Stage 4: ~ 360–630 mm DW, USNM 216235 female 500 mm DW and USNM 216238 (female 634 mm DW) with denticle band well-developed and continuous along tail; band relatively narrow, absent laterally beside orbit and spiracle, with irregular margins; margin broadly rounded on preorbit, extending anteriorly from orbit to orbit; suprascapular denticles small but distinct from remnant primary denticle row on nape; denticles extending over entire dorsal and most of ventral tail. Band in USNM 216239 (female 360 mm DW) similar to largest specimens, converging posteriorly on disc (rather than being truncate).

Meristics. Total pectoral-fin radial count for types 129-130 (127–135) (n=5); propterygium 52 (51–54), mesopterygium 16 (18–21), metapterygium 61-62 (58–61). Pelvic-fin radials 28-29 (24–28). Vertebral centra, including synarcual 109 (102–111); monospondylous 43 (41–47), pre-sting diplospondylous 66 (55–68); and poststing diplospondylous 0.

TABLE]. Measurements expresseđ as a percentage of đisc wiđth (DW) for holotypes of Maculabatis arabica n. sp. (LACM 38133-74, female 325 mm DW), M. bineeshi sp. (LACM 38131-43, immature male 241 mm DW) anđ M. randalli ( CSIRO H 7254.01, ađult male 412 mm DW). Ranges are given for paratypes.

M. arabica M. bineeshi M. randalli

Holotype Paratypes Holotype Paratypes Holotype Paratypes

Range Range Range

Disc wiđth (mm) 325 234 268 241 198 250 412 245 414

Total length đamageđ 300.0 338.0 322.0 273.4 337.4 264.2 251.9 319.0

Disc length 90.2 88.8 92.5 93.8 92.5 98.0 97.7 92.5 97.6

Snout to pectoral-fin insertion 80.4 77.7 83.0 84.4 82.9 88.3 85.2 85.9 87.1

Orbit to pectoral-fin insertion 57.1 53.3 58.6 60.7 59.6 60.9 58.9 57.4 64.3

Snout to maximum đisc wiđth 42.4 40.9 43.2 41.5 39.4 41.4 39.7 39.1 42.6

Snout to origin of cloaca 74.2 72.8 76.6 77.5 76.3 81.9 81.9 77.1 79.9

Cloaca origin to tail tip đamageđ 223.4 261.6 244.5 234.7 255.4 182.3 172.1 241.8

Cloaca origin to cauđal sting 37.1 31.7 36.5 37.6 36.1 39.9 36.8 36.3 41.7

Pectoral-fin insertion to cauđal sting (horiz.) 34.1 27.6 33.8 32.2 31.5 35.1 32.5 30.8 34.7

Disc thickness 12.3 9.2 14.1 12.0 10.6 13.2 13.6 12.3 16.9

Snout (preorbital) length 20.7 20.5 21.2 20.5 20.4 23.4 22.4 20.1 22.7

Snout (preorbital horiz.) length 19.3 18.5 19.4 19.2 17.7 21.7 20.3 18.0 21.7

Orbit điameter 5.3 5.9 6.5 6.9 6.2 6.9 5.2 4.6 5.7

Eye điameter 3.3 3.4 3.7 3.9 3.0 4.0 3.1 2.6 3.7

Spiracle length 7.1 6.4 7.6 5.9 6.4 7.2 6.1 6.1 6.7

Orbit anđ spiracle length 9.6 9.6 10.8 10.1 10.2 11.4 9.4 9.3 10.6

Interorbital wiđth 11.8 11.2 12.1 12.8 12.6 13.8 12.8 12.8 15.0

Inter-eye wiđth 17.7 17.0 17.8 20.0 19.0 20.7 17.5 18.4 20.3

Interspiracular wiđth 17.0 16.4 18.0 18.8 18.8 19.2 17.5 17.5 18.9

Heađ length 43.8 43.2 45.6 44.6 44.0 48.6 46.8 44.5 46.0

Preoral length (to lower jaw) 21.2 20.5 22.0 21.4 20.5 23.3 22.6 21.9 21.9 ……continued on the next page TABLE]. (Continueđ)

M. arabica M. bineeshi M. randalli

Holotype Paratypes Holotype Paratypes Holotype Paratypes Range Range Range Colour. Holotype (preserved): Disc uniformly light brown, plain without white spotting; ventral surface uniform pale (whitish); weakly-defined, moderately broad yellowish-brown margins, beginning near disc apices and continuing to rear tip of pectorals; free rear tips of pelvic fins similar. Tail uniformly light brown anteriorly on dorsal surface; strongly banded on upper half behind caudal-sting base in juveniles (smaller than 33 cm DW); becoming plainer and darker brown in subadults and adults (bands indistinct or absent); occasionally faint, evenly spaced white spots present along dorsolateral surface between tail base and caudal sting in small juveniles.

Size. Largest specimen USNM 216238 (female 634 mm DW); adult males 438 mm DW (BPBM 27511) and 450 mm DW (USNM 216246); male immature at 360 mm DW (USNM 216247). Birth size probably slightly smaller than 17 cm DW.

Distribution. Arabian Sea, off Pakistan (Sonmiani Bay, Baluchistan and west of Turshian Creek, Sind) and eastward to nearby Gujarat Province, India ( Fig. 14 ). A specimen taken near Cochin ( India) appears to be this species so it is possibly more widespread along the Indian west coast.

Etymology. Epithet given as a noun in apposition for this Arabic whipray. Vernacular: Pakistan Whipray ( Manjaji, 2004).

Remarks. Types of M. arabica sp. nov. are based on specimens from localities in Pakistan and India and possibly previously misidentified as Himantura gerrardi . Records from elsewhere in the northern Indian Ocean, may be misidentifications in part (e.g. Anon. 1955, on H. uarnak ) or were not recorded (e.g. Bianchi, 1985). Knowledge of the distribution of M. arabica is further complicated as it is sympatric with the very similar Arabian banded whipray, M. randalli . Additional specimens are required to determine the actual ranges of these species.

Figures

FIGURE 1. Holotype of Maculabatis arabica sp. nov., juvenile female 325 mm DW (LACM 38133 - 74, preserved) from Sind, Pakistan: (A) Dorsal view; (B) 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.