New turtle remains from the Late Cretaceous of Monte Alto-SP, Brazil, including cranial osteology, neuroanatomy and phylogenetic position of a new taxon

Abstract

A high diversity of land vertebrates is known from the Late Cretaceous deposits of the Bauru 21 Basin, Brazil, including at least five turtle taxa, all belonging to the clade Podocnemidoidae. Some of the 22 richest fossil sites of this basin are in the area of Monte Alto, which yielded several squamate, dinosaur, 23 and crocodyliform taxa. Yet, the single turtle reported so far from this area was only briefly described. 24Here, we further describe that specimen, a complete but very crushed shell, as well as a partial skull, both 25 found in outcrops of the Adamantina Formation. Comparison of the shell to other podocnemidoid taxa 26 reveals its affinities to Roxochelys wanderleyi, a turtle originally described from that same stratigraphic 27 unit. The comparative description of the skull and its inclusion in a phylogenetic study, supports the 28 proposal of a new taxon representing a lineage (Peiropemydodda) so far known only from the Marília 29 Formation of the Bauru Basin and the early Paleocene of Bolivia. The digitally reconstructed endocast 30 and inner ear of the new taxon were also described, as not previously done for a fossil pleurodire.31 32

Cretaceous Blind Snake from Brazil Fills Major Gap in Snake Evolution

“…The fossil comes from a rural road between the municipalities of Monte Alto and Taiaçu, in the Northwest of the state of São Paulo, Brazil ( Figure 1 B) (S21° O9′53.9″/W48°29′54.0″). The outcrop bearing the new material is a rich fossiliferous locality that preserves an abundant fauna including crocodyliforms ( Carvalho et al., 2007 ; Iori and de Souza Carvalho, 2009 ; Iori and Carvalho, 2011 ; Iori and Garcia, 2012 ; Iori et al., 2013 ; Iori and Campos, 2017 ), testudines ( Ferreira et al., 2018 ), and dinosaurs such as sauropods and non-avian theropods ( Méndez et al., 2014 ; Santucci and Arruda-Campos, 2011 ; Tavares et al., 2014 ). The sediments in the outcrop consist of the typical reddish muddy sandstones of the Adamantina Formation (Bauru Basin) found in the Monte Alto region ( Batezelli, 2017 ).…”

A new pelomedusoid turtle,Sahonachelys mailakavava, from the Late Cretaceous of Madagascar provides evidence for convergent evolution of specialized suction feeding among pleurodires

“…The semicircular canals are relatively slender and accordingly have small diameters in comparison with most turtles [ 50 ]. However, the semicircular canals are somewhat thicker than those of most extant pleurodires [ 50 , 57 ] and described fossil pleurodires [ 14 , 43 ]. The semicircular canal cross-sections are approximately circular, although the LSC is somewhat more oval (dorsoventrally compressed) than the vertical canals, as is the case in most turtles [ 50 ].…”