Extinct genus of reptiles
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 .[ 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.
References
^ a b c 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" . Palaeontology . 51 (5): 1091–1106. Bibcode :2008Palgy..51.1091D . doi :10.1111/j.1475-4983.2008.00800.x .
^ 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. Bibcode :1997CRASE.325..525B . doi :10.1016/s1251-8050(97)89872-2 .
^ a b Martin, J. E. (2007). "New material of the Late Cretaceous globidontan Acynodon iberoccitanus (crocodylia) from Southern France". Journal of Vertebrate Paleontology . 27 (2): 362–372. doi :10.1671/0272-4634(2007)27[362:NMOTLC]2.0.CO;2 . S2CID 130433177 .
^ 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" . Proceedings of the Royal Society B . 285 (1881). doi :10.1098/rspb.2018.1071 . PMC 6030529 . PMID 30051855 .
^ 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. doi :10.7717/peerj.7562 . PMC 6839522 . PMID 31720094 .
^ Blanco, A. (2021). "Importance of the postcranial skeleton in eusuchian phylogeny: Reassessing the systematics of allodaposuchid crocodylians" . PLOS ONE . 16 (6): e0251900. Bibcode :2021PLoSO..1651900B . doi :10.1371/journal.pone.0251900 . PMC 8189472 . PMID 34106925 .