A pug-nosed crocodyliform from the Late Cretaceous of Madagascar

Abstract

Although the image of crocodyliforms as 'unchanged living fossils' is naive, several morphological features of the group are thought to have varied only within narrow limits during the course of evolution. These include an elongate snout with an array of conical teeth, a dorsoventrally flattened skull and a posteriorly positioned jaw articulation, which provides a powerful bite force. Here we report an exquisitely preserved specimen of a new taxon from the Late Cretaceous of Madagascar that deviates profoundly from this Bauplan, possessing an extremely blunt snout, a tall, rounded skull, an anteriorly shifted jaw joint and clove-shaped, multicusped teeth reminiscent of those of some ornithischian dinosaurs. This last feature implies that the diet of the new taxon may have been predominantly if not exclusively herbivorous. A close relationship with notosuchid crocodyliforms, particularly Uruguaysuchus (Late Cretaceous, Uruguay) is suggested by several shared derived features; this supports a biogeographical hypothesis that Madagascar and South America were linked during the Late Cretaceous.

The Late Triassic pseudosuchian Revueltosaurus callenderi and its implications for the diversity of early ornithischian dinosaurs

“…All herbivore-like archosaur teeth must have evolved from a laterally compressed, serrated and recurved plesiomorphic tooth form, so there is limited variability in the Bauplan of herbivore-like archosaur teeth. This can be seen in the similarity among teeth in a variety of archosaurs such as Revueltosaurus, aetosaurs, Silesaurus, ornithischians, prosauropods, therizinosaurs and some crocodylomorphs (Buckley et al 2000;Harris et al 2000).…”

Reptiles Extintos - Volumen en Homenaje a Zulma Gasparini

“…The biochron of most notosuchian clades is restricted to the Cretaceous, and ranges from the Aptian (Early Cretaceous) to the Maastrichtian (Late Cretaceous), although a lineage of notosuchians of debated affinities (Sebecidae) is recorded after the K/Pg extinction event, and survived until the Miocene in South America (Gasparini, 1972Kellner et al, 2014). O 'Connor et al, 2010;Sertich and O'Connor, 2014) and Madagascar (Buckley and Brochu, 1999;Buckley et al, 2000;Simons and Buckley, 2009). Furthermore, fragmentary (but still informative) remains found in Indo-Pakistan (Wilson et al, 2001;Prasad and de Broin, 2002;Prasad et al, 2013), Central Asia (Chimaerasuchus; Wu and Sues, 1996), and Europe (Company et al, 2005;Dalla Vechia and Cau, 2011;Rabi and Sebök, 2015) suggests that the geographic distribution of Notosuchia was broader than previously thought.…”

“…5.1). An important contribution to the Campanian-Maastrichtian diversity is found in Madagascar (Maevarano Formation; Buckley and Brochu, 1999;Buckley et al, 2000;Turner, 2006;Rasmusson Simons and Buckley, 2009). Other regions have provided records of ziphodont crocodyliforms by the end Cretaceous linked to different groups of notosuchians, such as Europe (Company et al, 2005) or Pakistan (Wilson et al, 2001).…”

O estudo dos répteis fósseis-cresce a contribuição da ciência brasileira

“…Existem formas com dentes possuindo várias cúspides (pontas) como os encontrados em Candidodon, que chegou a ser equivocadamente classificado como um mamífero (34). Também foram encontradas espécies com dentes em forma de folha sugerindo hábitos herbívoros (35); outros com dentes curtos e robustos, dispostos diagonalmente nas arcadas, possuindo lâminas indicando que eram utilizados para quebrar material resistente, como ossos, (36); e até mesmo uma espécie que possuía dentes dispostos em uma plataforma formada pela região do dentário (principal osso da mandíbula), possivelmente utilizados para amassar e triturar o alimento (37). Todas essas variações dentárias, que são encontradas sobretudo (mas não unicamente) em espécies de depósitos brasileiros e africanos, demonstram que os notossúquios foram, sob o ponto de vista ecológico, os mais diversificados membros de Crocodylomorpha.…”