Eusuchian
| Eusuchia Temporal range: Early Cretaceous - Recent, 130–0 Ma |
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| Three species of living eusuchian: Gharial (left), American Alligator (center), and American Crocodile (right). | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Neosuchia |
| Clade: |
Eusuchia Huxley, 1875 |
| Subgroups | |
The Eusuchia ("true crocodiles") are a clade of crocodylomorphs that first appears in the Early Cretaceous with Hylaeochampsa. Along with Dyrosauridae and Sebecosuchia, they were the only crocodyliformes who survived the K-T extinction. Since the other two clades died out 35 and 11 million years ago, all living crocodilian species are eusuchians, as are many extinct forms.
Unlike primitive crocodylomorphs, crocodyliforms have secondary bony palates. This feature enables living crocodylians to safely breathe in through their nostrils while the rest of the head (including the mouth) remains submerged. This structure reaches its greatest elaboration among eusuchians, in which the internal nares are completely surrounded by the pterygoid bones.
Cladogram after Holliday and Gardner, 2012:
Brevirostres (alligators and crocodiles)
Below is a cladogram after Puértolas, Canudo and Cruzado-Caballero, 2011:
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