Shamosuchus
| Shamosuchus Temporal range: Late Cretaceous,
| |
|---|---|
| Holotype specimen | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Pseudosuchia |
| Clade: | Crocodylomorpha |
| Clade: | Neosuchia |
| Family: | †Paralligatoridae |
| Genus: | †Shamosuchus Mook, 1924 |
| Type species | |
| †Shamosuchus djadochtaensis Mook, 1924
| |
Shamosuchus is an extinct genus of neosuchian crocodyliform that lived during the Late Cretaceous (Campanian) period in what is now the Djadochta Formation of Mongolia, approximately 75 million to 71 million years ago.
Description
Shamosuchus reached up to 4 m (13 ft) long and had a rostrum of moderate length.[2] In S. djadochtaensis, a perinarial fossa extended along the ventrolateral region of the narial opening. Where the premaxilla and maxilla articulate, the alveolar margin is continuous and is characterised by the absence of a notch for receiving the opposing mandibular tooth.[3]
Taxonomy
The genus was named in 1924 by Charles C. Mook.[4] Paralligator was synonymized with Shamosuchus by several authors.[5][6][7] However, recent cladistic analysis of Paralligatoridae found the former genus to be distinct from the latter.[8]
Phylogeny
Below are the results of a phylogenetic analysis by Pol et al., 2009 showing the position of Shamosuchus within Neosuchia:[3]
Palaeobiology
The eye and nasal openings were not raised above the skull as in modern crocodilians, so that the animal would have to raise its head completely out of the water to breathe. As this cranial morphology does not suit an ambush predator, it lends support to the idea of a diet of aquatic invertebrates. The morphology of the teeth of Shamosuchus suggests they were adapted to crush bivalves, gastropods, and other animals with a shell or exoskeleton.[4]
References
- ^ Rio, Jonathan P.; Mannion, Philip D. (6 September 2021). "Phylogenetic analysis of a new morphological dataset elucidates the evolutionary history of Crocodylia and resolves the long-standing gharial problem". PeerJ. 9 e12094. doi:10.7717/peerj.12094. PMC 8428266. PMID 34567843.
- ^ G. Storrs, M. B. Efimov. (2000). "Mesozoic crocodyliforms of north-central Eurasia". In book: The Age of Dinosaurs in Russia and Mongolia (pp.402-419) Publisher: Cambridge University PressEditors: Michael J. Benton, Michael A. Shishkin, David M. Unwin, Evgenii N. Kurochkin
- ^ a b Pol, Diego; Turner, Alan H.; Norell, Mark A. (30 June 2009). "Morphology of the Late Cretaceous Crocodylomorph Shamosuchus djadochtaensis and a Discussion of Neosuchian Phylogeny as Related to the Origin of Eusuchia". Bulletin of the American Museum of Natural History. 324: 1–103. doi:10.1206/0003-0090-324.1.1. Retrieved 21 October 2025 – via BioOne Digital Library.
- ^ a b Mook, C. C. (1924). "A new crocodilian from Mongolia" (PDF). American Museum Novitates (117): 1–5.
- ^ Efimov, M. B. (1983). "Review of fossil crocodiles of Mongolia". Transactions of the Joint Soviet–Mongolia Paleontological Expedition. 24: 76–95.
- ^ Rozhdestvenskiy, A. K. (1974). "History of the dinosaur fauna of Asia and other continents and questions concerning paleogeography". Transactions of the Joint Soviet–Mongolia Paleontological Expedition. 1: 107–131.
- ^ Storrs, G. W.; Efimov, M. B. (2000). "Mesozoic crocodyliforms of north-central Eurasia". In Michael J. Benton; Mikhail A. Shishkin; David M. Unwin; Evgenii N. Kurochkin (eds.). The Age of Dinosaurs in Russia and Mongolia. Cambridge University Press. pp. 402–419.
- ^ Turner, A. H. (2015). "A Review of Shamosuchus and Paralligator (Crocodyliformes, Neosuchia) from the Cretaceous of Asia". PLOS ONE. 10 (2) e0118116. Bibcode:2015PLoSO..1018116T. doi:10.1371/journal.pone.0118116. PMC 4340866. PMID 25714338.