Rhamphosuchus ("Beak crocodile") is an extinct genus of gavialidcrocodylians. 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]
Overview
Rhamphosuchus crassidens jawsAn 1868 illustration of specimens of R. crassidens (top and center) compared to other crocodylian fossils from the Sewalik Hills
Historically, 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 9.2–10.3 m (about 30–34 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 CretaceousalligatoroidDeinosuchus, the Early CretaceouspholidosauridSarcosuchus and the MiocenegavialidGryposuchus, 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]
^Heilprin, Angelo (1974). The Geographical and Geological Distribution of Animals: The International Science Series Vol. 57. Ayer Publishing. ISBN0-405-05742-3.
^ abHead, 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. S2CID220414868.
