Chordates • Earth.com

Australian grey smooth-hound

(Mustelus ravidus)

Description

The Australian grey smooth-hound or also known as the grey gummy shark (Latin Mustelus ravidus, meaning ‘greyish weasel’) is a species of houndshark classified under the large family Triakidae. It is one of the twenty-eight species belonging to the genus Mustelus, which are often small in length. While members of the genus Mustelus may be found globally in tropical and temperate waters, the grey gummy shark in particular is native to the Pacific Ocean and Indian Ocean waters surrounding Australia and is particularly widespread in deep coastal waters. The grey gummy shark is known to be a viviparous species and gives birth to live young. With little data available, it is regarded to have a relatively stable population and possesses little threat to humans. The grey gummy shark’s scientific name, Mustelus ravidus, is derived from the Latin words for weasel (mustela) and grey, respectively. Hence, the literal translation of Mustelus ravidus is ‘greyish weasel’. Mustelus is a reference to how sharks were addressed in ancient times as weasels or mustela. However, this is to be distinguished from the genus Mustela which is scientifically used for weasels. On the other hand, ravidus denotes the grey gummy shark’s dorsal colour. In general, the population distribution of the genus Mustelus, which the grey gummy shark is a part of, requires active swimming and is heavily associated with coastal-benthic (or ground-dwelling) areas. Specifically, the grey gummy shark is endemic to Australia. It is commonly found in continental shelves, particularly the north-west shelf off Western Australia, and usually at the depth range 106-300 metres. This oceanic range is usually referred to as the twilight zone which spans from 200 metres to 1000 metres and is partly or wholly impenetrable by sunlight. Notably, the grey gummy shark is often found in the upper range of the twilight zone. Like most members of the family Triakidae, the grey gummy shark has two large dorsal fins, an anal fin, and nictitating eyelids. It has a pale grey skin colour with no white or other coloured spots. A further analysis of the shark’s fins shows that it has an expanded and curved ventral caudal lobe. Furthermore, the grey gummy shark’s dorsal fins are curved slightly backwards; its front and back dorsal fin have a white and dusky tip, respectively while its terminal caudal lobe has a distinct black tip.

Taxonomic tree:

Domain:
Kingdom: Animalia
Phylum:
Class: Elasmobranchii
Order:Carcharhiniformes
Family:Triakidae
Genus:Mustelus
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