Rusty Catshark

description

Description. Proportions as percentages of total length for the holotype and paratypes (7) are presented in Table 1. H. maculosus n. sp. (n = 6) H. sellus n. sp. (n = 14) Mean Min Max Mean Min Max Egg case length (mm) 47.5 45.4 49.5 49.0 44.9 51.0 Posterior case width 39.2 38.3 40.2 41.2 38.1 45.0 Waist width 25.7 25.3 25.9 25.2 20.0 29.8 Anterior case width 30.1 29.4 30.5 31.2 28.9 34.4 Anterior border width 17.9 16.7 19.1 19.1 17.2 21.0 Posterior border width 4.1 2.9 4.9 4.8 3.1 6.1 Egg case height 18.1 16.0 19.4 18.8 16.4 20.7 Body tapering, anterior trunk wide and somewhat depressed; length of trunk from fifth gill openings to vent 1.13 (1.00 – 1.31) times head length; tail long and slender, almost circular in cross-section at second dorsal-fin insertion; no lateral keels; height 0.99 (0.99 – 1.30) in width at second dorsal-fin insertion, 2.83 (2.72 – 3.45) in dorsal – caudal space; no postnatal ridge between anal fin base and lower caudal-fin origin; multiple weak longitudinal ridges on dorsal surface, extending from head to about second dorsal fin, usually indistinct, no other obvious lateral ridges. Head short, length 1.15 (1.01 – 1.18) to pectoral – pelvic space; wide and s

Halaelurus maculosus n. sp. and H. sellus n. sp., two new species of catshark (Carcharhiniformes: Scyliorhinidae) from the Indo – West Pacific

diagnosis

Diagnosis. Member of the genus Halaelurus with the following combination of characters: a relatively short, parabolic snout, preoral length 4.5 – 5.2 % TL; predorsal length 39.1 – 41.8 % TL, 3.4 – 3.8 times anal – caudal space; anal – caudal space 10.8 – 12.3 % TL; mouth relatively short, length 2.1 – 2.9 % TL; upper labial furrows very short (7.1 – 12.9 in eye length) but conspicuous; eyes of moderate size, eye length 2.9 – 3.3 % TL; pectoral fin with a rather angular apex, anterior margin 9.6 – 10.7 % TL, 1.5 – 1.9 times inner margin; anal fin of moderate size, length 9.3 – 10.8 % TL, anterior margin 6.9 – 7.9 % TL; adult clasper very elongate and narrow, outer length 8.1 – 8.8 % TL, 6.3 – 6.5 times clasper base length, extending past the pelvic-fin free rear tip by 0.68 – 0.80 times pelvic-fin inner margin length, clasper tip sharply pointed; total vertebral centra 126 – 132, precaudal centra 79 – 83; dorsal surface with broad, dark brownish saddles bordered with variable, dark brown spots; spots absent from interspaces between saddles. Small adult size, attaining about 420 mm TL.

Halaelurus maculosus n. sp. and H. sellus n. sp., two new species of catshark (Carcharhiniformes: Scyliorhinidae) from the Indo – West Pacific

distribution

Distribution. Occurs off northwestern Australia from off Shark Bay (Western Australia) to the Arafura Sea (Northern Territory) (see Fig. 9). Habitat. Demersal on the continental shelf at depths of 62 – 164 m.

Halaelurus maculosus n. sp. and H. sellus n. sp., two new species of catshark (Carcharhiniformes: Scyliorhinidae) from the Indo – West Pacific

etymology

Etymology. Derived from the Latin sella meaning saddle in allusion to the primary colouration of dark saddles on the head and body. Comparisons. Halaelurus sellus is similar in appearance to H. buergeri, but is separable based on morphometrics and colour. Halaelurus sellus possesses very short (<1.8 mm) labial furrows, similar to H. buergeri, but differs from this species in the consistency of their development (Fig. 6). The colour pattern of H. sellus differs from that of H. buergeri in having smaller and less defined (occasionally barely visible) dark spots bordering the saddle markings (Figs 5 and 10). Halaelurus sellus also differs from H. buergeri in morphometrics: first dorsal-fin height 3.8 – 4.3 vs. 4.9 – 5.1 % TL; eye length 2.9 – 3.3 vs. 3.4 – 4.3 % TL, 4.1 – 5.3 The two new species described here, H. maculosus and H. sellus, not only differ remarkably in colour pattern, but also in several morphometric and meristic characters: pectoral-fin anterior margin length 10.8 – 11.7 in H. maculosus vs. 9.6 – 10.7 % TL in H. sellus; anal-fin size (length 11.0 – 12.2 vs. 9.3 – 10.8 % TL, base length 9.0 – 10.2 vs. 7.6 – 8.9 % TL); adult clasper outer length 7.3 – 7.5 vs. 8.1 – 8.8

Halaelurus maculosus n. sp. and H. sellus n. sp., two new species of catshark (Carcharhiniformes: Scyliorhinidae) from the Indo – West Pacific