Author: Gill, 1862
Field Marks:
Scyliorhinids with short and rounded or pointed snouts, no nasoral grooves, anterior nasal flaps small and not reaching mouth, upper and lower labial furrows short, sometimes absent, inner margins of pelvic fins not connected, second dorsal not greatly smaller than first, caudal fin short, without enlarged denticles on dorsal margin, no supraorbital crests on cranium, colour pattern variably present or absent.
Diagnostic Features:
Body not tadpole-shaped, slender to moderately stout and cylindrical or fusiform, tapering slightly or moderately to caudal fin; body firm and thick-skinned, with dermal denticles well-calcified or weakly so; stomach not inflatable; tail fairly short to rather long, length from vent to lower caudal origin about 2/5 of total length, to about equal to snout-vent length. Head moderately to considerably depressed, narrowly rounded to wedge-shaped in lateral view; head short to moderately long, between 1/4 and 1/5 to less than 1/5 of total length in adults; snout short to moderately long, less than 4/5 of mouth width, thick and slightly flattened, bluntly to narrowly pointed in lateral view; snout not expanded laterally, rounded, parabolic, pointed, or somewhat bell-shaped in dorsoventral view; ampullal pores not greatly enlarged on snout; nostrils of moderate size, with incurrent and excurrent apertures only partly open to exterior; anterior nasal flaps broadly triangular, narrow and elongated, or reduced and pointed, without barbels, well separate from each other and falling slightly to considerably anterior to mouth; internarial space about 0.6 to 1.1 times in nostril width; no nasoral grooves; eyes dorsolateral on head, broad subocular ridges present below eyes; mouth angular, semiangular, or rounded, short to moderately long, with lower symphysis well behind upper so that upper teeth are exposed in ventral view; labial furrows present along both upper and lower jaws, these short to very short and occasionally absent (H. buergeri), ending well behind level of upper symphysis of mouth when present; branchial region not greatly enlarged distance from spiracles to fifth gill slits 1/3 to slightly less than 3/5 of head length; gill slits lateral or dorsolateral on head. Two dorsal fins present, about equal-sized or with the second slightly smaller or larger than first; origin of first dorsal varying from slightly in front of the pelvic midbases to about over their insertions; origin of second dorsal varies from slightly in front of anal midbase to about over anal insertion; pectoral fins moderately large, their width subequal to or somewhat greater than mouth width; inner margins of pelvic fins not fused over claspers in adult males; claspers moderately long, fairly slender to moderately stout, and distally pointed, extending about half of their lengths behind the pelvic fin tips; anal fin moderately large but not greatly elongated, about as large as pelvic fins or slightly smaller or larger, subequal to or larger than the dorsals, its base length subequal to about twice the second dorsal base; origin of anal well behind pelvic bases, and insertion separated from lower caudal origin by a narrow to very broad space less than a fourth to over the length of the anal base; caudal fin short and broad to narrow and moderately elongated, between 1/4 and 1/5 to less than 1/5 of total length in adults; no crests of denticles on the caudal margins. Supraorbital crests absent from cranium. Colour light grey or brown to blackish without markings, or variably patterned with dark spots, saddles and vertical bars.
Remarks:
This genus has been revised by Springer (1966, 1979) and Springer and D'Aubrey (1972); the present arrangement is adopted from their work with some modifications. These revisions removed species with supraorbital crests on their crania from Halaelurus: H. bivius and H. chilensis were included in the genus Schroederichthys, and H. Iabiosus in Aulohalaelurus. In addition, two Australian species without supraorbital crests, H. analis and H. vincenti, were separated from Halaelurus and from each other in the Whitleyian genera Asymbolus and Juncrus, but these genera are defined only on minor clasper and associated pelvic fin characters, and appear to be not separable from each other. Although these Australian taxa appear not to be closely related to typical Halaelurus (H. buergeri and allied species), the differences that distinguish them might be better expressed by ranking them together as a subgenus of Halaelurus. Even without these Australian species, Halaelurus remains a heterogeneous assemblage that may bear subdivision into at least two subgenera. Typical Halaelurus includes a presumably closely related cluster of similar Indo-West Pacific sharks, H. buergeri, H. boesemani, H. natalensis, H. lineatus, and H. quagga; all these species have rather flat, short heads with more or less pointed and sometimes upturned snouts, similar fin shapes and positions, firm skins, barred and spotted colour patterns, and dorsolateral gill slits; they appear to be closely related to the aberrant 'satellite genera' Holohalaelurus and Haploblepharus which share many of their features but are more specialized. It is uncertain if the remainder of Halaelurus species, unspotted, deepwater, often soft-skinned sharks with lateral gills form a coherant group or not, some of these, especially H. canescens, are rather Parmaturus-like. H. alcocki is a poorly known black, canescens-like shark that may or may not belong to this genus. A provisional account of this species is included below, but due to uncertainties on its distinguishing characters it is not included in the key to species.