Taxonomy and Phylogeny
The Cuban naturalist Felipe Poey published the first description of the blacknose shark in 1860 as Squalus acronotus, in his Memorias sobre la historia natural de la Isla de Cuba. Later authors moved this species to the genus Carcharhinus. The type specimen was a 98-cm (3.2-ft)-long male caught off Cuba.
Based on morphological data, Jack Garrick suggested in 1982 that the blacknose shark has a sister relationship to a group containing the whitecheek shark (C. dussumieri) and the blackspot shark (C. sealei), while Leonard Compagno proposed in 1988 that this shark belongs in a group with five other species, including the silky shark (C. falciformis) and the blacktip reef shark (C. melanopterus). Molecular analyses have been similarly equivocal regarding the blacknose shark's phylogenetic relationships: Gavin Naylor's 1992 allozyme analysis found this species to be the most basal member of Carcharhinus, while Mine Dosay-Abkulut's 2008 ribosomal DNA analysis indicated affinity between it and the blacktip shark (C. limbatus) or the smalltail shark (C. porosus). The whitenose shark (Nasolamia velox), found along the tropical western coast of the Americas, may be descended from blacknose sharks that experienced the teratogenic effects of incipient cyclopia.
Read more about this topic: Blacknose Shark