Scientists have described a new species of shark in the waters of northern Australia.
The new Weasel shark has just been named Hemigaleus australiensis in a paper in the systematics journal Zootaxa, and is only the second known member of the genus.
The description, written by William White of Murdoch University, Perth, Peter Last of CSIRO and Leonard Compagno of the Shark Research Centre, Cape Town, says that the new Hemigaleus species differs from its congener, H. microstoma, in the presence of a black mark on the tip of the second dorsal fin, as well as having far fewer vertebrae and lots more teeth on its lower jaw.
The new fish Hemigaleus australiensis, which is a member of the Carcharhiniformes family Hemigaleidae, is known from inshore bays on the continental shelves of northern Australia and lives in water up to 170m/557' deep.
Its closest relative, H. microstoma, commonly known as the the Weasel shark or Sicklefin weasel shark, is a small and slender species roughly the same shape and size as the Smooth hound sharks, Mustelus spp. native to UK waters, which reaches around 1m/39" in length.
H. microstoma is relatively common in the waters around Indonesia, Thailand and Singapore and has paler fins often with white spots on the tips of the fins and the flanks. It lacks the black mark seen on the second dorsal of australiensis.
H. microstoma feeds on crustaceans and cephalopods, particularly octopuses, and is often caught as a food species.
For more details on the new shark species see the paper: White, WT., Last, PR. and JV Compagno (2005) - Description of a new species of weasel shark, Hemigaleus australiensis n. sp. (Carchariniformes: Hemigaleidae) from Australian waters. Zootaxa 1077: 37-49.