The skull of Sanajeh indicus, a Cretaceous snake with an upper temporal bar, and the origin of ophidian wide-gaped feeding

Autor(es)

Zaher, Hussam ; Mohabey, Dhananjay M. ; Grazziotin, Felipe G. ; Wilson Mantilla, Jeffrey A.

• Tipo de documento: Artigo Científico
• Fonte: ZOOLOGICAL JOURNAL OF THE LINNEAN SOCIETY; v. N/A, p. 42-pg., 2022-05-13.

Resumo

Recent phylogenetic analyses differ in their interpretations of the origin and interrelationships of snakes, resulting in polarized views of snake ecology, habit and acquisition of features associated with wide-gaped feeding (macrostomy). Here, we report a new specimen of the Late Cretaceous nest predator Sanajeh indicus that helps to resolve the origin of macrostomy. The new specimen preserves an ossified upper temporal bar and a posteriorly expanded otooccipital region that lacks a free-ending supratemporal bone and retains a lizard-like palatomaxillary arch that allows limited movements during swallowing. Phylogenetic analyses of a large-scale total evidence dataset resolve Sanajeh near the base of Pan-Serpentes, as the sister group of Najash, Dinilysia and crown-group Serpentes. The Cretaceous Tetrapodophis and Coniophis represent the earliest-diverging members of Pan-Serpentes. The Cretaceous hindlimbed pachyophiids and Cenozoic Australian 'madtsoiids' are inside crown Alethinophidia, whereas mosasaurs are recovered invariably within anguimorphs. Our results suggest that the wide-gape condition in mosasaurs and snakes might have evolved independently, as functionally distinct mechanisms of prey ingestion. The intermediate morphology preserved in Sanajeh indicates that ingestion of large prey items (macrophagy) preceded wide-gaped, unilateral feeding (macrostomy), which appeared 35 Myr later, in the common ancestor of pachyophiids, Cenozoic Australian 'madtsoiids' and alethinophidians. (AU)

• Processo FAPESP: 18/11902-9 - Origem e diversificação dos grandes grupos de serpentes: fósseis-chaves basais e a irradiação Cenozóica de Colubroides (Squamata)
• Beneficiário: Hussam El Dine Zaher
• Modalidade de apoio: Bolsas no Exterior - Pesquisa
• Processo FAPESP: 11/50206-9 - Origem e evolução das serpentes e a sua diversificação na região neotropical: uma abordagem multidisciplinar
• Beneficiário: Hussam El Dine Zaher
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Temático