Borneo catshark

description

Apristurus platyrhynchus: Garman, 1913: 98 (description, Japan); Nakaya, 1975: 28, fig. 12 (description, Japan); Springer, 1979: 26 (description, Japan); Compagno, 1984: 278 – 279 (description, Japan); Nakaya in Masuda et al., 1984: 4, pl. 335 - B (description, Japan); Nakaya, 1989: 201, fig. 2 (comparative material); Nakaya & Sato, 1999: 316 (taxonomic comments); Nakaya & Séret, 1999: 307 (comparative materials); Nakaya & Sato, 2000: 224 (description, Japan, China, Philippines, and Indonesia; figs 1 – 2; Yoshino & Aonuma, 2002: 130 (key to species, Japan); Compagno et al., 2005: 198, pl. 32 (description, Japan, Philippines and Australia); Kawauchi et al., 2008: 75, figs 1, 3, 6 (description, Japan, East China Sea, Philippines, South China Sea, and Australia); Last & Stevens, 2009: 194, fig. 25, 31.7 (description, Japan, Philippines and Australia); Ebert et al., 2013: 297, pl. 38 (description). Apristurus macrorhynchus: Chen, 1963: 33, fig. 11 (description, Taiwan). Pentanchus verweyi Fowler, 1934: 237, fig. 2 (original description, type locality: Indonesia); Fowler, 1941: 57 (key to species and description, Japan). Apristurus verweyi: Compagno, 1984: 287 (description, Indonesia);

A review of the genus Apristurus (Chondrichthyes: Carcharhiniformes: Scyliorhinidae) from Taiwanese waters

description

Description. Proportional measurements and meristic counts are given in Table 5. Body cylindrical, slender and elongate (Figure 31). Head dorso-ventrally flattened, posterior part of body compressed laterally. Snout rather long; tip bell-shaped. Pre-outer nostril length slightly greater than internarial width. Pre-oral length slightly less than preorbital length, 2.2 – 2.9 times internarial width, slightly greater than mouth width and greater than interorbital width. Pre-orbital length 1.3 – 2.1 times of interorbital length, 2.4 – 4.3 times orbit length. Internarial width subequal to orbit and nostril width. Nostril expanding obliquely inward from snout edge; length about half of pre-inner nostril length. Nostril – mouth space about half of internarial width. Mouth widely arched, with well developed labial furrows; upper labial furrows 1.3 – 1.8 times longer than lower one. Upper labial furrow reaching beyond midpoint between mouth corner and posterior margin of nostril. Orbit narrow and slender, with a weak subocular fold. Spiracle very small placed slightly below level of horizontal axis of orbit. Five small gill slits present; third gill slit above pectoral-fin origin; fifth gil

A review of the genus Apristurus (Chondrichthyes: Carcharhiniformes: Scyliorhinidae) from Taiwanese waters

diagnosis

Diagnosis. A species of Apristurus with the following characters: upper labial furrows much longer than the lowers; first dorsal fin much smaller than second dorsal fin, originating above middle of P 2 – anal space; second dorsal-fin insertion well anterior to anal-fin insertion; snout rather long, tip bell-shaped; abdomen very short; P 1 – P 2 space shorter than three fifths of anal-fin base length (ceratotrichia); pectoral-fin tip always extending beyond midpoint of P 1 – P 2 space; intestinal spiral valves 16 – 20; monospondylous + precaudal diplospondylous vertebrae 33 – 40 + 37 – 45; clasper hook absent on edge of exorhipidion; body uniformly light blown or grey to dark blown; maturing size larger than 55 cm TL in both sex.

A review of the genus Apristurus (Chondrichthyes: Carcharhiniformes: Scyliorhinidae) from Taiwanese waters

discussion

Remarks. Apristurus platyrhynchus was originally described by Tanaka (1909) based on a mature male collected from Suruga Bay, Japan. This species belongs to the ‘ brunneus group’ (sensu Nakaya & Sato, 1999) of the genus Apristurus, characterized by having considerably longer labial furrows on the upper jaw than those on the lower jaw, and a greater number of spiral valves in the intestine. Since the original description of the species, no one worked on it until Nakaya (1975) made a taxonomic revision of Japanese scyliorhinid sharks. Later, Nakaya & Sato (2000) worked on A. platyrhynchus and its five related species, and synonymized both A. verweyi (Fowler, 1934) from the Philippines and A. acanutus Chu, Meng & Li, 1985 from the South China Sea with A. platyrhynchus. Recently, Kawauchi et al. (2008) further examined the specimens from Indonesia and Australia, and suggested that this species is widespread in Japan, Philippines, Indonesia, and even Australia. Among the species of Taiwan, Apristurus platyrhynchus resembles A. macrostomus in having a rather long snout, and a narrower interspace between the pectoral and pelvic fin bases, butit is distinguishable by a more posterior posit

A review of the genus Apristurus (Chondrichthyes: Carcharhiniformes: Scyliorhinidae) from Taiwanese waters