Mariliasuchus
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Mariliasuchus Temporal range: Late Cretaceous |
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| Mariliasuchus amarali | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Family: | †Notosuchidae |
| Genus: |
†Mariliasuchus Carvalho and Bertini, 1999 |
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Mariliasuchus ("Marilia crocodile") is an extinct genus of Late Cretaceous notosuchian mesoeucrocodylian found near Marilia, Brazil. The first bone remains were found and collected in 1995 by Brazilian paleontologist William Nava, in red rocks from Adamantina Formation. Four years later, it was described as "Mariliasuchus amarali", by Brazilian palaeontologists Ismar de Souza Carvalho and Reinaldo J. Bertini.
Its type species M. amarali, in honour of Sérgio Estanislaw do Amaral, Brazilian naturalist. A second species, M. robustus, was named in 2007.
Several specimens of M. amarali have been found close to eggs, eggshells and coprólites to date: UFRJ DG 50-R (holotype): a partially complete and articulated skeleton, including a nearly complete skull and partially preserved axial and appendicular skeletons. It belongs to a juvenile specimen. UFRJ DG 105-R. UFRJ DG 106-R. MZSP-PV 50. MZSP-PV 51. MN 6298-V. MN 6756-V. URC R 67. URC R 68. URC R 69. MPM 114 Ic V - 4 eggs. MPM 115 R. MPM 116 R. MPM 117 R. MPM 119 R.
All of these specimens have been recovered in a road cut, 10 km south from the city of Marilia, in outcrops known as "Estrada Velha" pto. 1 and 2. They come from the upper part of the Adamantina Formation, indicating a Late Cretaceous (possibly Campanian/Maastrichtian) age.
A phylogenetic analysis done by Zaher et al. (2006) found Mariliasuchus amarali to share a close relationship with Comahuesuchus. Andrade et al. (2006), while studying the palate and choanae of some mesoeucrocodylians, reached this same conclusion. Though no name was given to this clade in either publication, it is referred in this article as Comahuesuchidae.
Mariliasuchus, unlike modern crocodylians, was an animal of terrestrial habits (though see below). Its nostrils were located on the front of the skull, unlike modern crocodiles, in which the nostrils face upwards, to help the animal breathe while its almost completely submerged. Furthermore, the eyes in M. amarali are faced laterally (in modern crocodiles they face upwards). It had a very modified dentition, differentiated in incisiforms, caniforms and molariforms. Strangelly, in particular, were the anterior-most teeth, which were directed horizontally rather than vertically. The function of this strange arrangement is not yet clear, but Vasconcellos et al. (2002) made comparisons with the dentition of pigs, indicating that their dietary preferences may be convergent. It also had strong jaw muscles, indicating a good degree of mandibular activity.
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