Spotted Handfish

description

Description. D 1 2, n = 80 non types; D 2 17 – 19, usually 18, n = 69; A 8 – 10, very rarely 8, n = 69; Pc 6 – 8, usually 7; Pv i, 4; C 1 + 5 – 7 (usually 6) + 1 – 3 (usually 2) = 9; Vt 9 – 11 + 13 – 15 = 22 – 26 (usually 23 – 24), n = 14; Br 5, n = 1. Body moderately elongate, weakly compressed; upper anterior profile convex, elevated slightly, upper eye close to dorsal margin; subtriangular when viewed anteriorly; nape usually humped in large individuals; anterior ventral profile weakly convex to flattened; abdomen globose; caudal peduncle elongate, length 7 – 11 % SL. Head relatively short, 45 – 48 % SL; snout short, 4.8 – 5.8 times in head; eye small, 5.4 – 6.7 times in head length; gill opening small, aperture smaller than pupil, located slightly above and behind insertion of pectoral fin; nostrils large, openings mostly protruding slightly; posterior opening elevated above anterior opening, adjacent orbit. Mouth relatively small, terminal, moderately protractile; upper jaw slightly oblique, 3.6 – 4.1 in head; upper lip very fleshy; lower lip fleshy medially, connected laterally to lower jaw by fleshy dorsoventrally flattened fold; angle of jaw partly retracting into groove; t

A new handfish, Brachionichthys australis sp. nov. (Lophiiformes: Brachionichthyidae), with a redescription of the critically endangered spotted handfish, B. hirsutus (Lacepède)

diagnosis

Diagnosis. Esca small, 15 – 26 (mean 20) % of illicium length (including esca); illicium very slender, without dermal spinules, length 19 – 20 (mean 20) % SL, 2.3 – 2.4 times in head length; eye moderate, exceeding 5.4 times in head; body entirely covered with close-set, non-imbricate scales; scale bases subcircular with long unicuspid spinules (except for those closely-associated with pores of the acoustico-lateralis system); spinules originating from middle of scale base, variable in length over body; second dorsal-fin rays 17 – 19 (mean 18), fin base 61 – 64 (mean 62 %) SL; length of first ray of first dorsal fin 0.7 – 1.0 times length of longest ray of second dorsal fin; anal-fin rays 8 – 10; usually with 7 pectoral-fin rays; upper body usually covered with fine dark spots or short streaks (rarely with long streaks on head); caudal fin with dense coverage of fine spots, forming a dark submarginal bar in juveniles.

A new handfish, Brachionichthys australis sp. nov. (Lophiiformes: Brachionichthyidae), with a redescription of the critically endangered spotted handfish, B. hirsutus (Lacepède)

discussion

Remarks. The Spotted Handfish, Brachionichthys hirsutus, was reasonably common in the Derwent Estuary in the latter half of the 20 th Century (Last et al., 1983). In 1976 – 77, during a year-long, fortnightly survey of the fish community of this estuary, B. hirsutus was collected in 15 % of day and 12 % of night samples using a beach seine (Last, 1983). During the 1980 ’ s, it was ‘ commonly encountered by divers’ (Edgar et al., 1982). More recently, populations of B. hirsutus have become severely depleted (Barrett et al., 1996) and the species is considered to be critically endangered by multiple agencies, including the World Conservation Union (IUCN) Red List of Threatened Species (listed as Critically Endangered), the Australian Government (listed as Endangered under the Environment Protection and Biodiversity Conservation Act 1999) and The State Government of Tasmania (listed as Endangered under the Threatened Species Protection Act 1995). Brachionichthys hirsutus does appear to have undergone a recent range reduction. In the 1960 ’ s to late 1980 ’ s, collection data suggest that it was well established in the interconnected bays of southeastern Tasmania, including the D’Entre

A new handfish, Brachionichthys australis sp. nov. (Lophiiformes: Brachionichthyidae), with a redescription of the critically endangered spotted handfish, B. hirsutus (Lacepède)

distribution

Distribution. Demersal inshore, with an extremely narrow geographic and depth distribution. It is restricted to the Derwent Estuary and the adjacent bays of southeastern Tasmania. Populations appear to have been reduced significantly since its discovery and it is now considered to be critically endangered (IUCN, 2006). Hence, locality data in the materials section has been generalised to protect extant populations from selective poaching. A few specimens have locality records from well beyond the current known geographic range. The northern-most record is from near Coles Bay, central eastern Tasmania (near 42 ° 0 6 ′ S, 148 ° 0 9 ′ E), and the most southerly recorded is listed as Lymington, in the Cygnet Estuary (near 42 ° 0 9 ′ S, 147 ° 0 4 ′ E), an arm of the D'Entrecasteaux Channel. Occurs at depths of 1 – 60 m but anecdotal evidence suggests a range commonly of ca. 5 – 15 m.

A new handfish, Brachionichthys australis sp. nov. (Lophiiformes: Brachionichthyidae), with a redescription of the critically endangered spotted handfish, B. hirsutus (Lacepède)