Voay
Voay | |
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Skull, American Museum of Natural History | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Clade: | Archosauromorpha |
Clade: | Archosauriformes |
Order: | Crocodilia |
Family: | Crocodylidae |
Subfamily: | Crocodylinae |
Genus: | †Voay Brochu, 2007 |
Type species | |
†Voay robustus (Grandidier & Vaillant, 1872)
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Synonyms | |
Crocodylus robustus Grandidier & Vaillant, 1872 |
Voay is an
Description
V. robustus would have measured around 3.5–4 m (11–13 ft) long and weighed about 170 kg (370 lb).[5][6] These estimates suggest that V. robustus was the largest predator to have existed in Madagascar in recent times. Its size, stature, and presumed behavior is similar to the modern Nile crocodile (Crocodylus niloticus). Because V. robustus shared so many similarities with the Nile crocodile there must have been a great deal of interspecific competition for resources between the two crocodile genera if they were to have coexisted with one another. It has recently been proposed that the Nile crocodile only migrated to the island from mainland Africa after V. robustus had become extinct in Madagascar.[5] However, this was subsequently disproved after some Crocodylus specimens from Madagascar were found to be at least 7,500 years old and contemporaneous with Voay.[7]
Phylogenetics
When V. robustus was first described in 1872, it was originally assigned to the genus Crocodylus.[8] It was later found to morphologically have had more in common with the extant Osteolaemus, or dwarf crocodile, than Crocodylus. Some features it shared with Osteolaemus include a depressed pterygoid surface that forms a choanal "neck" on the palate. Because it was not close enough to be placed in the same genus as the dwarf crocodile, it was assigned to the new genus in 2007. Before this reassignment, the species was considered by some to be synonymous with Crocodylus niloticus. However, this was most likely due to a misinterpretation of remains from the living C. niloticus with V. robustus and the poor description of the original material from which the species was described.[9][10] In contrast to the morphological similarities with Osteolaemus, a 2021 study using paleogenomics found Voay to be a sister group to Crocodylus, with both genera diverging in the mid-late Oligocene; this indicates that the apparent similarities with Osteolaemus are likely due to convergent evolution.[11]
The below cladogram shows the results of the latest study:[11]
Crocodylidae
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(crown group) |
References
- PMID 34567843.
- .
- S2CID 85731694.
- ^ Hill, R. V. & Lucas, S. G. (2006). "New data on the anatomy and relationships of the Paleocene crocodylian Akanthosuchus langstoni". Acta Palaeontologica Polonica. 51 (3): 455–464.
- ^ .
- PMID 11724953.
- S2CID 249146169.
- ^ Grandidier, A. and Vaillant, L. (1872). Sur le crocodile fossile d'Amboulintsatre (Madagascar). Comptes Rendus de l'Académie des Sciences Paris 75:150–151.
- ^ Mook, Charles C. "Description of a skull of the extinct Madagascar crocodile, Crocodilus robustus Vaillant and Grandidier" (PDF). Bulletin of the American Museum of Natural History. 44 (4): 25.
- ^ Brochu, C. A. and Storrs, G. W. (1995). The giant dwarf crocodile: a reappraisal of ‘Crocodylus’ robustus from the Quaternary of Madagascar. In: Patterson, Goodman, and Sedlock, eds., Environmental Change in Madagascar. p. 70.
- ^ PMID 33907305.