Dentition of etmopterid shark Miroscyllium (Squaliformes) with comments on the fossil record of lanternsharks
Résumé
Although modern lantern sharks (Etmopteridae, Squaliformes) are taxonomically diverse, their phylogenetic relationships remain unclear. Numerous fossil etmopterids have been recently discovered, and their geologic occurrences are reviewed here. The dentition of the rare recent etmopterid Miroscyllum sheikoi is described. The species shows peculiar ontogenetic changes in the morphology of lower and upper teeth, and allows to assign some fossil material described as Centroscyllium by Ledoux (1972) to Miroscyllium. Moreover, the presence, in Miroscyllium sheikoi, of a morphological transitional dental type between Etmopterus and Centroscyllium, and its discovery in the fossil record allow to propose an alternative way to contribute to the phylogenetic frameworks.