Acta Palaeontologica Polonica

Phylogenetic position of the crocodylian Megadontosuchus arduini and tomistomine palaeobiogeography

Paolo Piras, Massimo Delfino, Letizia Del Favero, and Tassos Kotsakis

Acta Palaeontologica Polonica 52 (2), 2007: 315-328

A cladistic analysis of Megadontosuchus arduini from the middle Eocene of Monte Duello ( NE Italy ) confirms its tomistomine relationships, but the low number of scorable characters determines a low resolution within the tomistomine clade. However, Megadontosuchus is clearly distinct from the other Eocene European or North African tomistomines, in having a moderate elongated but robust rostrum, massive maxillary and dentary teeth and large supratemporal fenestrae. The rostrum and teeth characteristics could indicate that M. arduini had a degree of feeding specialization intermediate between Maroccosuchus zennaroi and the Eocene European tomistomines. A summary of tomistomine palaeobiogeography suggests that despite only one species with a rather restricted range survives at present, such a clade had a glorious past with a world wide distribution documented by a conspicuous fossil record that starts at least in the early Eocene. At present, a detailed knowledge of tomistomine palaeobiogeography is hindered by the lack of modern taxonomic revisions of some fossil remains and therefore by the poor understanding of phylogenetic relationships.

Key words: Crocodylidae, Tomistominae, Tomistoma schlegelii, palaeobiogeography, Eocene, Italy.

Paolo Piras and Tassos Kotsakis, Dipartimento di Scienze Geologiche, Universitŕ Roma Tre, Largo S. Leonardo Murialdo 1, I-00146, Roma, Italy; Massimo Delfino, Dipartimento di Scienze della Terra, Universitŕ di Firenze, Via La Pira 4, I-50121 Firenze, Italy; Letizia Del Favero, Museo di Geologia e Paleontologia, Universitŕ degli studi di Padova, Via Giotto 1, I-35137, Padova, Italy.

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