Australian Blacktip Shark - Taxonomy and Phylogeny

Taxonomy and Phylogeny

The Australian blacktip shark was described by Australian ichthyologist Gilbert Percy Whitley in a 1950 issue of the scientific journal Western Australian Naturalist. He named it Galeolamna pleurotaenia tilstoni in honor of Richard Tilston, assistant surgeon at Port Essington, Northern Territory. The type specimen is a 1.5 m (4.9 ft) long female caught from Van Cloon Reef in Joseph Bonaparte Gulf. Later authors have regarded Galeolamna as a synonym of the genus Carcharhinus. This shark may also be referred to as blacktip whaler, Tilston's whaler shark, and Whitley's blacktip shark.

After Whitley's initial description, C. tilstoni was generally regarded as synonymous with C. limbatus, the common blacktip shark. In the 1980s, additional morphological and life history data again favored the recognition of C. tilstoni as a separate species, which was eventually confirmed by allozyme studies performed by Shane Lavery and James Shaklee. Several molecular phylogenetic studies based on allozymes, mitochondrial DNA, and nuclear DNA have found that that the Australian and common blacktip sharks form a closely related clade with the graceful shark (C. amblyrhynchoides) and the smoothtooth blacktip shark (C. leiodon). The interrelationships between them have not been fully resolved, but available data suggest that C. tilstoni and C. limbatus are not the most closely related species within the clade despite their similarity.