Rhamphosuchus ("Beak crocodile") is an extinct genus of gavialid crocodylians. It lived during the Pliocene and its fossils have been found in two regions; the Siwalik Hills of Pakistan and India as well as the Sindh region of Pakistan. Its type species is Rhamphosuchus crassidens, which is only known from incomplete sets of fossils, mostly teeth and skulls. Four species traditionally placed in the genus Gavialis may be included as well.[1]

Rhamphosuchus
Temporal range: 5.333–2.588 Ma
Pliocene
Life restoration
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauromorpha
Clade: Archosauriformes
Order: Crocodilia
Family: Gavialidae
Subfamily: Gavialinae
Genus: Rhamphosuchus
Falconer & Cautley, 1840
Type species
Rhamphosuchus crassidens
Falconer & Cautley, 1840

Overview

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Rhamphosuchus crassidens jaws
 
An 1868 illustration of specimens of R. crassidens (top and center) compared to other crocodylian fossils from the Sewalik Hills

Traditionally, many palaeontologists estimated that it was one of the largest, if not the largest crocodylian that ever lived, reaching an estimated length of 15 to 18 m (49 to 59 ft).[2] However, a more recent study suggests that the animal may have been 8–11 m (26 to 36 ft) in length, and therefore is not the largest known crocodylian.[3] Another crocodylian, Purussaurus, from the Miocene of Peru and Brazil, is known from an equally incomplete fossil set. It is estimated to have been similar in length to the initial estimates at approximately 9.2m (about 35 ft). However, this would mean that it would have been somewhat larger in size if the more recent size estimates for Rhamphosuchus are correct. If the most recent estimate is correct, then several other extinct crcoodilians and crocodylomorphs likely surpassed Rhamphosuchus in weight , such as the Late Cretaceous alligatoroid Deinosuchus, the Early Cretaceous pholidosaurid Sarcosuchus and the Miocene gavialid Gryposuchus, at 10.6 m, 9.5 m and 10 m, respectively.

Rhamphosuchus was previously regarded as a close relative of the modern false gharial within the subfamily Tomistominae. However, Tomistominae in its traditional sense is now known to be paraphyletic, and a 2022 study by Iijima and colleagues recovered Rhamphosuchus as a derived member of the subfamily Gavialinae instead.[4] Rhamphosuchus probably had a more generalized predatory diet than the piscivory of other "tomistomines".[3]

See also

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References

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  1. ^ Martin, J. E. (2018). "The taxonomic content of the genus Gavialis from the Siwalik Hills of India and Pakistan" (PDF). Papers in Palaeontology. 5 (3): 483–497. doi:10.1002/spp2.1247.
  2. ^ Heilprin, Angelo (1974). The Geographical and Geological Distribution of Animals: The International Science Series Vol. 57. Ayer Publishing. ISBN 0-405-05742-3.
  3. ^ a b Head, J. J. (2001). "Systematics and body size of the gigantic, enigmatic crocodyloid Rhamphosuchus crassidens, and the faunal history of Siwalik Group (Miocene) crocodylians". Journal of Vertebrate Paleontology. 21 (Supplement to No. 3): 59A. doi:10.1080/02724634.2001.10010852. S2CID 220414868.
  4. ^ Iijima, M.; Qiao, Y.; Lin, W.; Peng, Y.; Yoneda, M.; Liu, J. (2022). "An intermediate crocodylian linking two extant gharials from the Bronze Age of China and its human-induced extinction". Proceedings of the Royal Society B: Biological Sciences. 289 (1970): 20220085. doi:10.1098/rspb.2022.0085. PMC 8905159. PMID 35259993.