Ikanogavialis had a dorsoventrally deep snout and a distinctive notch between the dentary and maxillary alveoli.[3] The external nares projected anterodorsally from the rostrum. This can be seen as a plesiomorphic characteristic in crocodilians, but given that the earliest gavialoids possessed dorsally projecting external nares, this feature can be seen as having been a reversal from the gavialoid apomorphy back to the crocodilian plesiomorphy rather than having been directly obtained from an early crocodilian ancestor.
Additionally, a Pleistocene gavialoid found on Woodlark Island of Papua New Guinea was initially named Gavialis papuensis in 1905, but has since been proposed to be a member of Ikanogavialis,[4] although the poor quality of the preserved material makes it difficult to determine.[1]
Paleobiology
Ikanogavialis may have lived in a coastal paleoenvironment along with other gavialids such as Gryposuchus. The strata of the Urumaco formation were deposited in both marine and fluvial settings, although it is unclear to which portion both genera belong.[5][6] Other gavialoids such as Siquisiquesuchus and Piscogavialis are known to have lived in coastal environments, and it is likely that extant freshwater gavialoids such as Gavialis may have originated from these coastal forms.[7][8]Ikanogavialis also existed with many other crocodilians in Venezuela during the late Miocene including the giant caimanPurussaurus and an extinct species of Melanosuchus.[9]
"Gavialis" / Ikanogavialis papuensis was similarly fully marine, having been found in association with sea turtles and sirenians. It represents the youngest fully marine crocodilian to date.[10]
^Langston, W.; Gasparini, Z. (1997). "Crocodilians, Gryposuchus, and the South American gavials". In Kay, R. F.; Madden, R. H.; Cifelli, R. L.; Flynn, J. J. (eds.). Vertebrate Paleontology in the Neotropics: The Miocene fauna of La Venta, Colombia. Washington, D.C.: Smithsonian Institution Press. pp. 113–154. ISBN1-56098-418-X.
^Sill, W. D. (1970). "Nota preliminar sobre un nuevo gavial del Plioceno de Venezuela y una discusion de los gaviales sudamericanos" [Preliminary note on a new gharial Pliocene of Venezuela and a discussion of the South American gavials]. Ameghiniana. 7: 151–159.
^Linares, O. J. (2004). "Bioestratigrafia de la fauna de mamiferos de las Formaciones Socorro, Urumaco y Codore (Mioceno Medio–Plioceno Temprano) de la region de Urumaco, Falcon, Venezuela". Paleobiologia Neotropical. 1: 1–26.
^Sánchez-Villagra, M. R.; Aguilera, O. A. (2006). "Neogene vertebrates from Urumaco, Falcón State, Venezuela: diversity and significance". Journal of Systematic Palaeontology. 4 (3): 213–220. doi:10.1017/S1477201906001829. S2CID84357359.
^Kraus, R. (1998). "The cranium of Piscogavialis jugaliperforatus n. gen., n. sp. (Gavialidae, Crocodylia) from the Miocene of Peru". Paläontologische Zeitschrift. 72 (3–4): 389–406. doi:10.1007/BF02988368. S2CID84214781.
^Brochu, C. A.; Rincon, A. D. (2004). "A gavialoid crocodylian from the Lower Miocene of Venezuela". Special Papers in Palaeontology. 71: 61–78.
^Aguilera, O. A.; Driff, D.; Bocquentin-Villanueva, J. (2006). "A new giant Purussaurus (Crocodyliformes, Alligatoridae) from the Upper Miocene Urumaco Formation, Venezuela". Journal of Systematic Palaeontology. 4 (3): 221–232. doi:10.1017/S147720190600188X. S2CID85950121.
^Molnar, R. E. (1982). "A longirostrine crocodilian from Murua (Woodlark), Solomon Sea". Memoirs of the Queensland Museum. 20: 675–685.
