The evolution of mammal-like crocodyliforms in the Cretaceous Period of Gondwana.
Nature
; 466(7307): 748-51, 2010 Aug 05.
Article
em En
| MEDLINE
| ID: mdl-20686573
ABSTRACT
Fossil crocodyliforms discovered in recent years have revealed a level of morphological and ecological diversity not exhibited by extant members of the group. This diversity is particularly notable among taxa of the Cretaceous Period (144-65 million years ago) recovered from former Gondwanan landmasses. Here we report the discovery of a new species of Cretaceous notosuchian crocodyliform from the Rukwa Rift Basin of southwestern Tanzania. This small-bodied form deviates significantly from more typical crocodyliform craniodental morphologies, having a short, broad skull, robust lower jaw, and a dentition with relatively few teeth that nonetheless show marked heterodonty. The presence of morphologically complex, complementary upper and lower molariform teeth suggests a degree of crown-crown contact during jaw adduction that is unmatched among known crocodyliforms, paralleling the level of occlusal complexity seen in mammals and their extinct relatives. The presence of another small-bodied mammal-like crocodyliform in the Cretaceous of Gondwana indicates that notosuchians probably filled niches and inhabited ecomorphospace that were otherwise occupied by mammals on northern continents.
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Base de dados:
MEDLINE
Assunto principal:
Evolução Biológica
/
Fósseis
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Mamíferos
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article