Graceful Shark - Taxonomy and Phylogeny

Taxonomy and Phylogeny

Australian ichthyologist Gilbert Percy Whitley originally described the graceful shark as Gillisqualus amblyrhynchoides, in an 1834 issue of Memoirs of the Queensland Museum. He based his account on a 60 cm (24 in)-long immature female caught off Cape Bowling Green in Queensland, hence the alternate common name Queensland shark. Later authors have synonymized Gillisqualus with Carcharhinus.

As with most Carcharhinus species, the evolutionary relationships of the graceful shark are poorly resolved. Based on morphology, Jack Garrick concluded in 1982 that its closest relative was the blacktip shark (C. limbatus), and that the two were closely related to the spinner shark (C. brevipinna). Leonard Compagno, in his 1988 phenetic study, also grouped those species together, along with the smoothtooth blacktip shark (C. leiodon) and the finetooth shark (C. isodon). However, molecular phylogenetic techniques have since found this interpretation to be invalid for the spinner, blacktip, and finetooth sharks.