Acynodon

Acynodon is an extinct genus of eusuchian crocodylomorph from the Late Cretaceous, with fossils found throughout Southern Europe.

Acynodon Temporal range: Santonian - Maastrichtian, 86–68 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Skull of Acynodon iberoccitanus (ACAP-FXl)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauria
Clade:	Pseudosuchia
Clade:	Crocodylomorpha
Clade:	Metasuchia
Clade:	Neosuchia
Clade:	Eusuchia
Genus:	†Acynodon Buscalioni et al., 1997
Species
†A. iberoccitanus Buscalioni et al., 1997 (type) †A. adriaticus Delfino et al., 2008 †A. lopezi Buscalioni et al., 1997

Classification

The genus Acynodon contains three species: A. iberoccitanus, A. adriaticus, and A. lopezi. Fossils have been found in France, Spain, Italy, and Romania, dating back to the Santonian and Maastrichtian periods of the Late Cretaceous.^[1]

When first described in 1997, it was placed within the family Alligatoridae.^[2] New findings a decade later led to it being reclassified as a basal globidontan.^[3][1] Recent studies have since resolved Acynodon as a basal eusuchian crocodylomorph, outside of the Crocodylia crown group, and a close relative to Hylaeochampsa.^[4][5][6]

Description

The skull of Acynodon is extremely brevirostrine; it had a very short and broad snout compared to other known alligatorids.^[3] Its dentition was quite derived, with enlarged molariform teeth and a lack of maxillary and dentary caniniform teeth, presumably an adaptation to feed on slow prey with hard shells.^[1] The paravertebral osteoderms of Acynodon were distinctively double-keeled.

A. adriaticus was highly specialized to durophagy, likely in shallow, densely vegetated waters. It had an acute lateral snout profile of A. adriaticus in comparison to the more rounded shape of A. iberoccitanus.^[7]