New Miocene Caribbean gavialoids and patterns of longirostry in crocodylians

Jaramillo, C.; Moreno-Bernal, J.W.; Scheyer, T.M.; Salas-Gismondi, R.; Sánchez-Villagra, M.R.

dc.contributor.author	Salas-Gismondi, R.
dc.contributor.author	Moreno-Bernal, J.W.
dc.contributor.author	Scheyer, T.M.
dc.contributor.author	Sánchez-Villagra, M.R.
dc.contributor.author	Jaramillo, C.
dc.date.accessioned	2019-04-24T18:23:54Z
dc.date.available	2019-04-24T18:23:54Z
dc.date.issued	2018
dc.identifier.uri	https://hdl.handle.net/20.500.12866/6478
dc.description.abstract	Gavialoidea is a clade of slender- and long-snouted crocodylomorphs with a single living species, the Indian gharial Gavialis gangeticus. Because elongated snouts (longirostry) have evolved independently in several crocodylomorph clades, this head shape has been interpreted as an ecological adaptation. How this condition affected patterns of diversification and how longirostrine-associated cranial features changed through adaptive radiations remain poorly understood. Two new small gryposuchine gavialoids, Dadagavialis gunai gen. et sp. nov. (early Miocene, Panama) and Aktiogavialis caribesi sp. nov. (late Miocene, Venezuela), evidence remarkable Miocene diversification of longirostrine forms in the Neotropics and support transmarine biogeographical relations between northern South America, the Caribbean, and southernmost North America before the Isthmus of Panama was fully established. By integrating phylogenetics and geometric morphometrics, we focus on this gavialoid diversity to investigate patterns of longirostry across the crown group of crocodylomorphs (Crocodylia). Analyses revealed that the snout shape of gavialoids has occupied a small, distinct and almost invariable morphospace since the Cretaceous, in contrast with the morphologically labile snout shape of other crocodylians (crocodyloids and alligatoroids). Our results suggest iterative environmental shift occupations throughout gavialoid evolution without major changes in snout proportions, but involving conspicuous rearrangements of the circumorbital bones. The longirostrine gavialoid morphotype is a distinct adaptation for seizing small prey and typically includes short and wide premaxillae and enlarged ‘caniniform’ teeth only at the tip of the snout. In longirostrine crocodyloids (Tomistoma, Crocodylus intermedius), the conservation of powerful bites and ‘caniniforms’ closer to the jaw joints allowed them to exploit a wider range of prey sizes, which could explain their snout shape plasticity. Therefore, the Mio–Pliocene extirpation of gryposuchine gavialoids from the Caribbean by the arrival of Crocodylus is quite unlikely. The last gryposuchine survived throughout the Pliocene in the south-eastern Pacific, where Crocodylus has never been documented.	en_US
dc.language.iso	eng
dc.publisher	Taylor and Francis
dc.relation.ispartofseries	Journal of Systematic Palaeontology
dc.rights	info:eu-repo/semantics/restrictedAccess
dc.rights.uri	https://creativecommons.org/licenses/by-nc-nd/4.0/deed.es
dc.subject	evolution	en_US
dc.subject	Pacific Ocean	en_US
dc.subject	Pacific Ocean (Southeast)	en_US
dc.subject	Miocene	en_US
dc.subject	adaptation	en_US
dc.subject	morphology	en_US
dc.subject	phylogenetics	en_US
dc.subject	adaptive radiation	en_US
dc.subject	Alligatoroidea	en_US
dc.subject	conservation status	en_US
dc.subject	Cretaceous	en_US
dc.subject	crocodilian	en_US
dc.subject	Crocodylidae (all crocodiles)	en_US
dc.subject	Crocodylomorpha	en_US
dc.subject	Crocodylus	en_US
dc.subject	Crocodylus intermedius	en_US
dc.subject	Gavialinae	en_US
dc.subject	Gavialis gangeticus	en_US
dc.subject	Gavialoidea	en_US
dc.subject	Isthmus of Panama	en_US
dc.subject	morphometrics	en_US
dc.subject	morphometry	en_US
dc.subject	morphotype	en_US
dc.subject	Neotropical Region	en_US
dc.subject	Neotropics	en_US
dc.subject	North America	en_US
dc.subject	Panama [Central America]	en_US
dc.subject	Pliocene	en_US
dc.subject	reptile	en_US
dc.subject	Tomistoma	en_US
dc.subject	Venezuela	en_US
dc.title	New Miocene Caribbean gavialoids and patterns of longirostry in crocodylians	en_US
dc.type	info:eu-repo/semantics/article
dc.identifier.doi	https://doi.org/10.1080/14772019.2018.1495275
dc.subject.ocde	https://purl.org/pe-repo/ocde/ford#1.05.03
dc.relation.issn	1478-0941