Cerrejonisuchus
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Cerrejonisuchus Temporal range: Mid-Late Paleocene (Peligran-Itaboraian) ~60–58 Ma |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Family: | †Dyrosauridae |
| Genus: |
†Cerrejonisuchus Hastings et al., 2010 |
| Type species | |
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†Cerrejonisuchus improcerus Hastings et al., 2010 |
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Cerrejonisuchus is an extinct genus of dyrosaurid crocodylomorph. It is known from a complete skull and mandible from the Cerrejón Formation in northeastern Colombia, which is Paleocene in age. Specimens belonging to Cerrejonisuchus and to several other dyrosaurids have been found from the Cerrejón open-pit coal mine in La Guajira. The length of the rostrum is only 54-59% of the total length of the skull, making the snout of Cerrejonisuchus the shortest of all dyrosaurids.
At an estimated length of 1.22 metres (4.0 ft) to 2.22 metres (7.3 ft), Cerrejonisuchus was small for a dyrosaur. This size estimate is based on the dorsal skull lengths of specimens UF/IGM 29 and UF/IGM 31. Cerrejonisuchus has the shortest body length of any known dyrosaur, much smaller than that of the longest dyrosaur, Phosphatosaurus gavialoides, which was 7.22 metres (23.7 ft) to 8.05 metres (26.4 ft) in length.
Currently the only known specimens of Cerrejonisuchus are UF/IGM 29 (the type specimen), UF/IGM 30, UF/IGM 31, and UF/IGM 32. Of these, UF/IGM 29 and UF/IGM 31 are thought to represent fully mature individuals while UF/IGM 32 is thought to represent a less mature individual. In UF/IGM 31, the neurocentral sutures of the anterior dorsal vertebrae are closed, an indication of morphological maturity. Additionally, the presence of well-developed osteoderms is likely to be an indication that the animal was mature because in living crocodylians, the osteoderms begin calcification after 1 year and grow to articulate with other osteoderms to form a dermal shield at maturity. Also, the sutures that separate the bones of the skull in both specimens are fully fused, suggesting that the individuals have reached a late ontogenic stage. In contrast, UF/IGM 32 has an unfused nasal suture, suggesting that it was less mature than the other individuals. UF/IGM 32 is also noticeably smaller than the other specimens.
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