 The morphology of the crocodile shark suggests affinity with the megamouth shark (Megachasmidae), basking shark (Cetorhinidae), thresher sharks (Alopiidae), and mackerel sharks (Lamnidae).More recent phylogenetic analyses, based on mitochondrial DNA, have suggested that the crocodile shark is closely related to either the megamouth shark or the sand sharks (Odontaspididae).Alternately, analysis based on dentition suggests that the closest relatives of the crocodile shark are the thresher sharks, followed by the mackerel sharks.