Himantura javaensis Last & White, 2013, sp. nov.
Creators: name: Last, Peter R.
name: White, William T.
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Elasmobranchii
Myliobatiformes
Dasyatidae
Himantura
Himantura javaensis

description: Himantura javaensis sp. nov.
Figs 8–13; Table 3
Himantura cf walga: White et al., 2006: 260, figs (images are of the nominated holotype); White & Dharmadi, 2007: 1811. Himantura sp. 1: Ward et al., 2008: accessory publication 1 (page 1 of tree; 4 of the H. javaensis paratypes)
Holotype. MZB 21461, female 164 mm DW, Cilacap landing site, Central Java, Indonesia, 10 Jun. 2002.
Paratypes. (11 specimens) CSIRO H 5859-01, female 190 mm DW, CSIRO H 5859-03, adult male 212 mm DW, Cilacap landing site, Central Java, Indonesia, 17 Apr. 2001; CSIRO H 5860-08 (Genbank accession EU398861), female 197 mm DW, CSIRO H 5860-11 (Genbank accession EU398860), female 234 mm DW, CSIRO H 5860-12, female 198 mm DW, CSIRO H 5860-14, female 170 mm DW, Cilacap landing site, Central Java, Indonesia, 22 Mar. 2002; CSIRO H 6129-01, adolescent male 173 mm DW, Cilacap landing site, Central Java, Indonesia, 23 Mar. 2002; AMS I 46280-001, juvenile male 120 mm DW, NMV A 30997-001, adult male 210 mm DW, MZB 15053 (Genbank accession EU398859), female 171 mm DW, MZB 15060 (Genbank accession EU398858), male 169 mm DW, Cilacap landing site, Central Java, Indonesia, 10 Jun. 2002.
Other material. (3 specimens) MZB 15055, male 144 mm DW, Cilacap landing site, Central Java, Indonesia, 23 Mar. 2002; MZB 15057, female 231 mm DW, MZB 15061, female 173 mm DW, Cilacap landing site, Central Java, Indonesia, 10 Jun. 2002.
Diagnosis. A very small species of Himantura (to at least 23 cm DW) distinguished by the following combination of features: disc suboval with a long, and broadly pointed snout, angle 104–111°, its length equal to or slightly longer than its width; pectoral-fin apices very broadly rounded, angle 101–104°; orbits small, weakly protrusible, 5–6% DW; short nostrils 3–4% DW; narrow internasal width, 9–10% DW; undamaged tail long, 2.1– 2.2 times DW; sting situated relatively posteriorly on tail, distance from cloaca origin to sting 38–42% DW; pelvic fins relatively small, length 17–20% DW; relatively short claspers, 18–19% DW in adult males; 1–3 (usually 1) small, seed- or heart-shaped suprascapular denticles, no large scute-like thorns or spines on dorsal surface; secondary denticle band well formed and sharply demarcated in adults, very narrow over branchial region, broadest over abdomen, then converging posteriorly near pectoral-fin insertions; tail usually entirely naked; dorsal surface mainly uniformly brownish when skin undamaged, disc margin slightly paler brown; ventral disc and tail white with dark margins on pectoral and pelvic fins, and dark blotches over first four gill slits; pectoral-fin radials 103– 108; total vertebral count (excluding first synarcual centra) 96–100.
Description. Disc variably suboval and pointed anteriorly, width 0.99 times length in female holotype (0.95– 1.00 in the 5 paratypes,> 173 mm disc width, DW); depressed, not greatly raised at mid-scapular region, maximum thickness 9% (7–9%) of DW; preorbital snout long, forming broad lobe at the snout tip, angle 109° (104–111°); disc width 2.07 (2.04–2.14) and distance from snout tip to pectoral-fin insertion 1.88 (1.89–1.98) times distance from snout tip to point of maximum width respectively; anterior margin of disc strongly concave, apex very broadly rounded, posterior margin broadly and evenly convex, free rear tip rounded, angle of pectoral-fin apex 101° (101–104°). Pelvic fins subtriangular, short, length 19.1% (17.3–19.7%) DW; lateral margin almost straight, apex narrowly pointed; free rear tip broadly rounded, combined with inner and posterior margins to form strongly convex edge; width across base 16.2% (15.1–17.9%) DW, 1.17 (1.06–1.19) in pelvic-fin length. Clasper of adult male relatively short, stout basally, tapering strongly, depressed slightly, its postcloacal length 18.4–18.9% DW in adult and late adolescent males; lining of pseudopera smooth; hypopyle short, about 40% of length of clasper outer margin; without prominent anterior notch. Tail very slender, semi-rigid, long, its length 2.09 (2.10–2.21) times DW, 2.42 (2.35–2.49) times precloacal length; tapering gradually and evenly toward sting, then with very weak taper beyond sting to finely pointed tail tip; base relatively narrow, moderately depressed, its width 1.84 (1.41–1.66) times its height; slightly less depressed below sting base, its width 1.38 (1.32–1.46) times its height; sting not positioned well forward on tail, distance from cloaca origin to sting 2.16 (2.09–2.33) in precloacal length, 40% (37–40%) disc length; dorsal groove housing stinging spine tapering gradually and persistent for about snout length behind sting base; in adults posterior tail subrectangular, its dorsal surface almost flat, ventral surface with shallow median furrow, lateral edge weakly convex.
Snout elongate, bluntly pointed, very depressed; preoral snout length 3.48 (3.23–3.80) times mouth width, 3.11 (2.85–3.26) times internarial distance, 1.32 (1.34–1.43) times distance between first gill slits; direct preorbital snout length 2.49 (2.28–2.62) times interorbital length; distance from snout tip to maximum disc width 48% (47– 49%) DW; interorbital space almost flat, weakly concave across preorbit; eye small, length 1.94 (1.54–1.78) in spiracle length; orbits not greatly protrusible, diameter 1.22 (0.95–1.19) in spiracle length, interorbital distance 2.15 (1.91–2.45) times orbit, intereye distance 2.92 (2.51–3.15) times orbit. Spiracles large 6.6 (5.6–6.5)% DW, suboval, situated dorsolaterally. Nostrils short, narrow, slightly oblique, outer margin raised slightly with a weak double concavity; internasal distance 2.63 (2.35–2.77) in prenasal length, 2.43 (2.44–2.80) times nostril length. Nasal curtain relatively broad compared to its length, width 2.05 (1.85–2.16) times length; lateral margins straight to weakly concave, smooth edged, barely to weakly diverging posteriorly; apices narrowly rounded, situated within broad groove; posterior margin very finely fringed, almost straight.
Mouth narrow, width 8.4% (7.5–9.1%) DW, 1.12 (1.07–1.23) in internasal width; profile moderately arched but variably, not obviously more so in adult male holotype than in large females; upper jaw strongly double concave, dorsal to lower jaw; lower jaw concave near symphysis, largely concealing and slotting into expanded symphysial knob of upper jaw; oronasal groove prominent, deep; skin along margin of lower jaw barely corrugated, confined to narrow strip around lips. Teeth of adult male paratype (NMV A 30997-001) with larger cusps in upper jaw than in lower jaw; upper jaw teeth suboval to rhomboidal, largest near symphysis and on lateral knobs, more strongly cuspid near jaw angle; lower jaw teeth in strong quincunx, suboval near symphysis, more cuspid near jaw angle. In female paratype (CSIRO H 5860-11) teeth more broadly oval, in strong quincunx, largely acuspid. Tooth rows (in paratypes NMV A 30997-001and CSIRO H 5860-11) about 38–42 in upper jaw; holotype not dissected. Floor or mouth with 4 well-developed, simple, slender, elongate papillae (in paratypes NMV A 30997-001 and CSIRO H 5860-11); a pair situated close together centrally, and one on either side of mouth near its corners; medial papillae slightly longer than those near corner.
Gill opening margins moderately S-shaped, smooth-edged; length of first gill slit 1.27 (1.15–1.65) times length of fifth, 3.06 (2.28–2.97) in mouth width; distance between first gill slits 2.35(2.09–2.43) times internasal distance, 0.42 (0.39–0.41) of ventral head length; distance between fifth gill slits 1.43 (1.30–1.55) times internasal distance, 0.25 (0.24–0.26) in ventral head length.
Holotype Paratypes (n=5)
Min. Max. Disc width (mm) 164 173 234 Total length 296.3 299.5 309.2 Disc length 101 99.8 105.5 Snout to pectoral-fin insertion 90.9 90.9 96.6 Disc thickness 11.4 11 13.5 Snout (preorbital) length 28.8 28.3 30.2 Snout (preorbital) horizontal length 27.3 26.2 29.1 Pelvic-fin (embedded) length 19.1 17.3 19.7 Width across pelvic-fin base 16.2 15.1 17.9 Greatest width across pelvic fins 42.2 33.7 41.6 Cloaca origin to tail tip 209.8 210 220.7 Tail width at axil of pelvic fins 9.6 8.3 10
Tail height at axil of pelvic fins 5.2 5.4 6.7 Pectoral-fin insertion to sting origin 39.1 33.9 36.1 Cloaca origin to sting 40.1 38.1 42.1 Tail width at base of sting 4.3 3.8 4.6 Tail height at base of sting 3.1 2.9 3.2 Sting 1 length - - -
Snout preoral (to lower jaw) length 29.3 28.6 30.7 Mouth width 8.4 7.5 9.1 Distance between nostrils 9.4 9 10.3 Interorbital width 11.5 11.4 12.9 Inter-eye width 15.6 15.1 16.7 Snout to maximum width 48.3 46.8 49
Eye length 3.4 3.2 3.8 Orbit diameter 5.4 5.1 6
Spiracle length 6.6 5.6 6.5 Interspiracular width 17.9 17 18.4 Orbit and spiracle length 9.6 9.3 9.9 Nostril length 3.9 3.3 3.9 Snout prenasal length 24.8 24.1 26
Nasal curtain length 10 10 11.9 Nasal curtain width 4.9 4.8 5.7 Orbit to pectoral-fin insertion 57.2 57.4 61.5 Snout to origin of cloaca 86.5 83.8 89.5 Width 1st gill slit 2.8 2.8 3.4 Width 3rd gill slit 2.8 3 3.3 Width 5th gill slit 2.2 2 2.8 Head length 53.1 52.1 55.5 Distance between 1st gill slits 22.1 20.5 22.3
......continued on the next page Squamation. Ontogenetic stages (definitions following Manjaji, 2004) 2 and 4, evident from type series; stages 3, 5 and 6 appear to be inapplicable; denticle development relatively rapid, no obvious sexual dimorphism. Secondary denticle band well defined in adults, expanded over abdomen, constricted over branchial region, poorly developed on tail, and with sharply-defined margins; no enlarged spines or scutes on tail or disc; suprascapular denticles 1–3 (mainly 1), seed- or heart-shaped, length 1.1–2.1% DW, their distance from edge of spiracle 18.9– 19.9% DW; distance of denticle band from snout tip 24.8–27.5% DW; width of band across interorbit 10.2–11.1% DW; narrowest width of band preceding scapular region 6.8–9.3% DW; width of band at scapulocoracoid 20.3– 25.0% DW; width of band over abdomen 25.1–30.6% DW; width of band at pectoral-fin insertion 0.9–5.8% DW. Stinging spines missing from all types, except CSIRO H 5860-08 which has two spines, both broken off at their bases.
Developmental Stages 0–1: no specimens available.
Stage 2 (based on single paratype, 120 mm DW, AMS I 46280-001): squamation consisting of 2 slightly enlarged, seed-shaped, suprascapular denticles surrounded by narrow band of primary denticles; primary denticles small, flattened, heart-shaped; a smaller patch of denticles either side of suprascapular denticles. Small median patch of interspiracular denticles anteriorly, forming loose connection with scapular band. Posterior-most denticles of scapular band about an orbit diameter behind suprascapular denticles. Remainder of body naked, apart from small, widely spaced, upright denticles on dorsal surface of tail behind sting.
Stage 4 (164–234 mm DW): Secondary denticle band well developed, but its extension of band onto tail (as for Stage 3) variable; tail patches weak or absent. Secondary denticle band relatively consistent in shape in adults, with most variability in width across branchial region; its margin sharply defined; band semi-truncate just forward or orbit, covering most of interorbit, usually narrowing slightly at interspiracular space, then constricting over branchial region; usually broadest over abdominal region with its lateral margins converging posteriorly to merge at about level of pectoral-fin insertion; holotype lacking secondary denticles on pre-sting tail (in some paratypes, these denticles extending onto tail in a very narrow medial band only a few denticles wide); remainder of disc and pre-sting tail naked. Denticles on post-sting tail of paratypes in paired dorsolateral and lateral rows, absent from dorsal mid-line of tail; small partly embedded.
Meristics. Total pectoral-fin radials 103–104 (103–108, n=8); propterygials 47–48 (46–49), mesopterygials 11–13 (11–13) and metapterygials 43–45 (44–47). Total pelvic-fin radials 25 (23–27 in females; 17–19 plus clasper in males). Total vertebral segments (excluding first synarcual centra) 99 (96–100; n=4); monospondylous centra (excluding first synarcuals) 35 (36–37; n=8); diplospondylous centra 64 (60–64; n=4).
Coloration. When fresh (based on image of holotype MZB 21461. Dorsal surface of disc and pelvic fins more or less uniformly brownish or tan, often with blotchy areas due to skin abrasion or pinkish due to blood vessel rupture; outer margin of disc slightly paler brown; tail similar to disc with considerable abrasion on tail of holotype. Main denticle band slightly paler brown and well defined; eye blackish, darker than rest of orbit. Ventral surface mainly white with broad, well-defined, continuous, dusky band along outer margins of pectoral and pelvic fins; dusky area commencing at about level of mouth then extending to hind part of pectoral fin, its greatest width (slight exceeding width of internasal flap) near pectoral fin apex; prominent dusky blotches over anterior four gill slits; tail uniformly white. Colour in preservative similar, dusky areas on ventral surface becoming more greyish brown and dark branchial region becoming more contrasted with pale ventral surface.
Skeletal morphology. No dissections were carried out on this material. However, based on radiographs, the shape of the neurocranium is that of a ‘typical’ Himantura (Manjaji, 2004).
Size. Type specimens ranged in size from 120–234 mm DW; one adolescent male was 169 mm DW, one mature male was 212 mm DW. White & Dharmadi (2007) recorded 654 specimens during surveys of the Cilacap fish landing site between 92 and 243 mm DW. They reported a size at maturity for males of 171–176 mm DW and one pregnant female of 179 mm DW which contained a single embryo of 51 mm DW.
Distribution. Known only from the types collected from the Cilacap fish landing site in southern central Java, Indonesia (Fig. 13). Exact fishing grounds not known, but caught commonly by trammel net fishers operating in coastal waters in central Java and not caught further afield. Not observed at fish landing site surveys in western and eastern Java, or at Bali and Lombok, suggesting it has a very restricted distribution.
Himantura fai EU398839 Lombok, Indonesia
Himantura javaensis EU398858 Java, Indonesia Himantura javaensis EU398860 Java, Indonesia Himantura javaensis EU398861 Java, Indonesia Himantura javaensis EU398859 Java, Indonesia
Himantura walga EU398875 Jakarta, Indonesia Himantura walga HQ955940 Vietnam
Himantura walga EU398876 Jakarta, Indonesia Himantura walga EU398872 Jakarta, Indonesia Himantura walga EU398873 Jakarta, Indonesia Himantura walga EU398874 Jakarta, Indonesia
Himantura walga HQ956148 Sabah, Malaysia Himantura walga KF604912 Sabah, Malaysia Himantura imbricata GU673374 Qatar Himantura imbricata KF604917 Kuwait Himantura imbricata KF604909 Kuwait
2%
Etymology. Named with reference to the regional occurrence of this ray, off the coast of Java, Indonesia. Presently considered to be locally abundant and endemic to the region.
Barcode results. The 4 paratypes of H. javaensis with sequences available in the BOLD database (www.boldsystems.org) grouped closest to H. imbricata from the Arabian Gulf and H. walga from Indonesia, Vietnam and Malaysia using the CO1 marker (Fig. 12). The new species had an average sequence divergence of 13.4% (minimum interspecific divergence of 13.0%) from H. imbricata and 12.3% (minimum interspecific divergence of 11.7%).
Comparisons. Himantura javaensis belongs to a group of small, plain coloured, marine whiprays, with a distinctive oval-shaped disc and a long pointed snout, which includes Himantura imbricata and Himantura walga. Both H. imbricata and H. walga share a state uncommon in the genus Himantura in possessing a row of enlarged, spear-shaped thorns along the dorsal midline of the tail in adults. In H. javaensis, such thorns are absent from the tail, which is either naked or with a very narrow row of small denticles similar to those of the secondary denticle band of the disc. Himantura javaensi s has a very narrow known geographic range but its distribution overlaps with H. walga in Indonesia. These species are superficially similar but differ in meristics and some aspects of their morphometry and squamation. Comparing these species, based on data for H. walga presented by Manjaji (2004), H. javaensis has more vertebrae (total segments excluding first synarcual centra 96–100 vs. 84–96 in H. walga), generally a more brownish rather than greenish coloration, a longer tail (length 2.1–2.2 vs. 1.0–1.7 times DW), smaller eye (diameter 3.2–3.8% vs. 3.7–5.0% DW) and orbit (diameter 5.1–6.0% vs. 5.9–7.9% DW), a more posteriorly positioned sting (distance from pectoral-fin insertion to sting origin 34–39% vs. typically 20–32% DW), shorter adult claspers (post-cloacal length 18–19% vs. 22–23% DW), shorter pelvic fin (length 17.3–19.7% vs. 18.6–24.5% DW), shorter head (length 52.1–55.5% vs. 55.1–59.3% DW), shorter distance between the 5th gill slits (length 13.2–14.3% vs. 14.1–16.7% DW), and a mainly shorter nostril (length 3.3–3.9% vs. 3.5–5.2% DW) and nasal curtain (length 4.8–5.7% vs. 5.3–8.2% DW). The secondary denticle band appears to develop slightly earlier in H. javaensis and, apart from differences in the presence/absence of enlarged thorns on the tail, there are clear differences in squamation. For example, in H. walga, the secondary denticles of the disc continue in a broad band along the dorsal surface of the pre-sting tail (either weakly represented or absent in H. javaensis), the denticle band is subrectangular above the abdomen in adults (rather than laterally expanded), and the naked part on the snout is relatively shorter (distance 50–60% vs. 94–98% of horizontal snout length). The genus Himantura is presently under revision by the first author and Mabel Manjaji-Matsumoto, and this work will evaluate the supraspecific status of taxa and provide a key to species.
description: Published as part of Last, Peter R. & White, William T., 2013, Two new stingrays (Chondrichthyes: Dasyatidae) from the eastern Indonesian Archipelago, pp. 1-21 in Zootaxa 3722 (1) on pages 11-18, DOI: 10.11646/zootaxa.3722.1.1, http://zenodo.org/record/285126