Rafael G. Souza, Rodrigo G. Figueiredo, SÃrgio A. K. Azevedo, Douglas Riff & Alexander W. A. Kellner (2019)
Systematic revision of Sarcosuchus hartti (Crocodyliformes) from the RecÃncavo Basin (Early Cretaceous) of Bahia, north-eastern Brazil.Â
Zoological Journal of the Linnean Society: zlz057,
doi:
https://doi.org/10.1093/zoolinnean/zlz057https://academic.oup.com/zoolinnean/advance-article-abstract/doi/10.1093/zoolinnean/zlz057/5546069Sarcosuchus hartii was a top predator that inhabited the fluvial and coastal areas of north-eastern Brazil during the Early Cretaceous. Several fossil remains were recovered during the late 19th and early 20th centuries from strata that outcrop in the RecÃncavo Basin in the state of Bahia. A re-analysis of this material shows that S. hartii is a valid species. The Brazilian taxon differs from the African Sarcosuchus imperator in the unique pattern of anastomosing ornamentation observed on the enamel surface. The inclusion of S. hartii in a novel phylogenetic analysis recovered it inside Tethysuchia, a large clade comprising South and North American pholidosaurids along Elosuchidae and Dyrosauridae. The evolutionary origin of Sarcosuchus is likely related to a cladogenesis event that resulted from the break-up of Gondwana.
====
Giovanne M. Cidade, Daniel Fortier & Annie S. Hsiou (2019)
Taxonomic and phylogenetic review of Necrosuchus ionensis (Alligatoroidea: Caimaninae) and the early evolution and radiation of caimanines.Â
Zoological Journal of the Linnean Society: zlz051
doi:
https://doi.org/10.1093/zoolinnean/zlz051https://academic.oup.com/zoolinnean/advance-article-abstract/doi/10.1093/zoolinnean/zlz051/5546088Alligatoroidea is the most species-rich crocodylomorph clade of the Cenozoic of South America, with nearly all species belonging to the Caimaninae clade. However, the earliest records of Caimaninae in South America, which are from the Palaeocene, are based mostly on incomplete specimens, which increases the importance of detailed taxonomic and phylogenetic studies on these taxa. This paper offers a taxonomic and phylogenetic review of Necrosuchus ionensis, a caimanine species from the Salamanca Formation of the Palaeocene of Argentina. Necrosuchus ionensis is considered a valid species, albeit with a different diagnosis from that proposed by previous authors. The phylogenetic analysis shows, for the first time, that N. ionensis belongs to the derived Caimaninae clade Jacarea. However, a better understanding of the Jacarea clade is needed, and alternative placements for N. ionensis might be considered. Nevertheless, the placement of N. ionensis as a derived caimanine raises interesting perspectives on the early evolution and radiation of caimanines, which are thoroughly discussed in this paper together with other results obtained in this study, such as the recovery of the North American caimanines Bottosaurus and Tsoabichi as a clade.