A new sebecid mesoeucrocodylian from the Rio Loro Formation (Palaeocene) of north-western Argentina

Abstract

A new basal mesoeucrocodylian, Lorosuchus nodosusgen. et sp. nov., from the Palaeocene of north‐western Argentina is presented here. The new taxon is diagnosed by the presence of external nares facing dorsally, completely septated, and retracted posteriorly, elevated narial rim, sagittal crest on the anteromedial margins of both premaxillae, dorsal crests and protuberances on the anterior half of the rostrum, and anterior‐most three maxillary teeth with emarginated alveolar margins. This taxon is most parsimoniously interpreted as a bizarre and highly autapomorphic basal member of Sebecidae, a position supported (amongst other characters) by the elongated bar‐like pterygoid flanges, a laterally opened notch and fossa in the pterygoids located posterolaterally to the choanal opening (parachoanal fossa), base of postorbital process of jugal directed dorsally, and palatal parts of the premaxillae meeting posteriorly to the incisive foramen. Lorosuchus nodosus also shares with basal neosuchians a suite of derived characters that are interpreted as convergently acquired and possibly related to their semiaquatic lifestyle. The phylogenetic analysis used for testing the phylogenetic affinities of L. nodosus depicts Sebecidae as the sister group of Baurusuchidae, forming a monophyletic Sebecosuchia that is deeply nested within Notosuchia. Alternative phylogenetic placements of Sebecidae, such as the recently proposed affinities with peirosaurids, were also evaluated within the context of the present data matrix and found to be only marginally suboptimal. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163, S7–S36.

Reptiles Extintos - Volumen en Homenaje a Zulma Gasparini

“…One of the most relevant contributions was the creation of Notosuchia (Gasparini, 1971) (Gasparini, 1972) and Peirosauridae (Gasparini, 1982), which were not considered part of Notosuchia until recently Pol, 2003;Turner and Sertich, 2010;Pol and Powell, 2011;Pol et al, 2012Pol et al, , 2014 (Gasparini, 1982) by recognizing the distinctness of Peirosaurus torminni from all other crocodyliforms, while studying the type materials of this taxon described originally by Price (1955), and more complete material discovered in Patagonia. These studies therefore organized the known diversity of Cretaceous crocodyliforms from South America by recognizing four basic groups: Notosuchidae, Uruguaysuchidae, Peirosauridae, and Baurusuchidae.…”

“…see Pol and Powell, 2011) or to peirosaurids (forming the clade Sebecia; see Larsson and Sues, 2007). Irrespective of their debated affinities, this distinct clade of notosuchians has its closest relatives in the Cretaceous and therefore must have been originated prior to the K/Pg boundary.…”

The evolution of jaw mechanism and dental function in heterodont crocodyliforms

“…Edentosuchus (Pol et al 2004, Pol andPowell 2011) and in some analyses (e.g. Pol et al 2004) they are the sistergroup of the Protosuchus-Hemiprotosuchus clade.…”

Revisão sistemática e ontogenética dos materiais cranianos atribuídos ao gênero Mariliasuchus (Crocodyliformes, Notosuchia) e suas implicações taxonômicas e paleobiológicas

“…Alguns autores consideram uma associação íntima entre Sebecidae e Peirosauridae (Larsson & Sues, 2007;Sereno & Larsson, 2009), enquanto outros unem Sebecidae a Baurusuchidae (Turner & Calvo, 2005;Pol & Powell, 2011). Um táxon frequentemente problemático, principalmente por seu estado de preservação e consequente ausência de dados, é Pabwehshi pakistanensis Wilson et al, 2001, que alguns autores classificam como Baurusuchidae (Turner & Calvo, 2005;Nascimento & Zaher, 2011), enquanto outros pontuam uma associação maior com Sebecus (Riff, 2007) ou, ainda, como um grupo-irmão do clado {Peirosauridae + Sebecidae} (Larsson & Sues, 2007).…”

“…Um táxon frequentemente problemático, principalmente por seu estado de preservação e consequente ausência de dados, é Pabwehshi pakistanensis Wilson et al, 2001, que alguns autores classificam como Baurusuchidae (Turner & Calvo, 2005;Nascimento & Zaher, 2011), enquanto outros pontuam uma associação maior com Sebecus (Riff, 2007) ou, ainda, como um grupo-irmão do clado {Peirosauridae + Sebecidae} (Larsson & Sues, 2007). Outra divergência de opinião se dá no posicionamento de Sebecidae, dentro de Neosuchia (Larsson & Sues, 2007;Sereno & Larsson, 2009) ou dentro de Notosuchia (Ortega et al, 2000;Pol & Powell, 2011).…”