Genetic evidence for separation of two sharks,Carcharhinus limbatus andC. tilstoni,from Northern Australia

Allozyme electrophoresis was used to show that the two morphologically different groups ofCarcharhinus limbatus co-existing in waters to the north of Australia were distinct species. Forty-eight loci were examined in 967 specimens of the normal form and 20 specimens of the dark pelvic form collected between 1982 and 1985. Two loci exhibited nearly fixed allelic differences between the two forms, indicating that they must be considered as two distinct species. Further genetic analysis ofC. limbatus specimens from the West Indies (the typelocality) and South Africa showed that the rare dark pelvic form is the trueC. limbatus, while the normal form in Australian waters isC. tilstoni.