Acynodon Explained

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

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.^[1] Recent studies have since resolved Acynodon as a basal eusuchian crocodylomorph, outside of the Crocodylia crown group, and a close relative to Hylaeochampsa.^{[3] [4] [5]}

Description

The skull of Acynodon is extremely brevirostrine; it had a very short and broad snout compared to other known alligatorids.^[6] 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.

Notes and References

1. 10.1111/j.1475-4983.2008.00800.x . Delfino . M. . Martin . J. E. . Buffetaut . E. . 2008 . A new species of Acynodon (Crocodylia) from the Upper Cretaceous (Santonian-Campanian) of Villaggio del Pescatore, Italy . . 51 . 5. 1091–1106 . 2008Palgy..51.1091D . free .
2. Buscalioni . A. D. . Ortega . F. L. . Vasse . D. . 1997 . New crocodiles (Eusuchia: Alligatoroidea) from the Upper Cretaceous of southern Europe . Comptes Rendus de l'Académie des Sciences, Série IIA . 325 . 7 . 525–530 . 10.1016/s1251-8050(97)89872-2. 1997CRASE.325..525B .
3. Michael S. Y. Lee . Adam M. Yates . 27 June 2018 . Tip-dating and homoplasy: reconciling the shallow molecular divergences of modern gharials with their long fossil . . 285 . 1881 . 10.1098/rspb.2018.1071 . 30051855 . 6030529 . free.
4. Tobias Massonne . Davit Vasilyan . Márton Rabi . Madelaine Böhme . 2019 . A new alligatoroid from the Eocene of Vietnam highlights an extinct Asian clade independent from extant Alligator sinensis . PeerJ . 7 . e7562 . 10.7717/peerj.7562 . 31720094 . 6839522 . free .
5. Blanco . A. . Importance of the postcranial skeleton in eusuchian phylogeny: Reassessing the systematics of allodaposuchid crocodylians . 2021 . PLOS ONE . 16 . 6 . e0251900 . 10.1371/journal.pone.0251900. 34106925 . 8189472 . 2021PLoSO..1651900B . free .
6. 10.1671/0272-4634(2007)27[362:NMOTLC]2.0.CO;2 . Martin . J. E. . 2007 . New material of the Late Cretaceous globidontan Acynodon iberoccitanus (crocodylia) from Southern France . . 27 . 2. 362–372 . 130433177 .