Finetooth Shark - Taxonomy and Phylogeny

Taxonomy and Phylogeny

The finetooth shark was originally described as Carcharias (Aprion) isodon by French zoologist Achille Valenciennes, in Müller and Henle's 1839 Systematische Beschreibung der Plagiostomen. The type specimen is a 65 cm (26 in) juvenile male, possibly caught off the U.S. state of New York. This species was later moved to the genus Carcharhinus. The specific epithet isodon means "equal teeth" in Greek, and refers to the similar number of teeth in the upper and lower jaws. This species may also be referred to as the eventooth shark, smoothtooth shark, or night shark (usually used for C. signatus).

As is the case for most Carcharhinus species, attempts to analyze the finetooth shark's phylogenetic relationships have yielded variable results. In 1988, Leonard Compagno grouped this species with the spinner shark (C. brevipinna), blacktip shark (C. limbatus), graceful shark (C. amblyrhynchoides), and the smooth tooth blacktip shark (C. leiodon), on the basis of morphological characters. Gavin Naylor's 1992 allozyme analysis found that the finetooth shark is the second-most basal member of the genus next to the blacknose shark (C. acronotus). Mine Dosay-Akbulut's 2008 study, based on ribosomal DNA, suggested that the closest relative of the finetooth shark is the smalltail shark (C. porosus), and that the two species form a clade apart from other Carcharhinus species.