Palaeoenvironmental characterization of a crocodilian nesting site from the Late Cretaceous of Brazil and the evolution of crocodyliform nesting strategies

Author(s)

Marsola, Julio C. de A. ; Batezelli, Alessandro ; Montefeltro, Felipe C. ; Grellet-Tinner, Gerald ; Langer, Max C.

• Document type: Journal article
• Source: PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY; v. 457, p. 221-232, SEP 1 2016.
• Web of Science Citations: 3

Abstract

Despite the vast crocodyliform fossil record, little is known about the reproductive biology and nesting strategies of the extinct members of the group. Here we report a large accumulation of crocodilian fossil eggs from the type locality of the baurusuchid Pissarrachampsa sera. Sedimentary fades and architectural elements of the site support a palaeoenvironmental model with a shallow lacustrine, playa-lake system interacting to ephemeral braided fluvial channels, with aeolian influence and development of sandy soils. The presence of pedogenic calcretes in the palaeosols indicates arid to semi-arid conditions. The crocodilian affinity of the eggs is supported by the thin eggshell which bears wedge-shaped shell units with tabular microstructures. Furthermore, taphonomic data support an autochthonous assemblage of eggs and skeletal remains, hinting at a monotypical stratigraphic horizon and suggesting P. sera as the egg-laying taxon. The repeated pattern of four (eventually five) eggs per clutch at the site demonstrates that P. sera laid fewer eggs compared to modern crocodilians, indicating that k-selected reproductive strategy pattern is pervasive in the fossil record of Notosuchia. In the crocodyliform phylogenetic framework, the k-strategy and the ``egg clutch sizes{''} optimization of Notosuchia is opposite to the strategy with larger clutches consistently occurring in modern Crocodylia and Neosuchia, the sister Glade to Notosuchia. Yet, the lack of data on more early-branching taxa renders unclear which pattern is plesiomorphic for Crocodyliformes as a whole. (C) 2016 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 13/23114-1 - Review of the Carnian (Neotriassic) Sauropodomorpha (Dinosauria) with description of new elements of Saturnalia tupiniquim
• Grantee: Júlio Cesar de Almeida Marsola
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 10/19787-2 - Stratigraphic relationship and Paleogeography of the Upper Cretaceous in the Bauru, Sanfranciscana and Parecis basins
• Grantee: Alessandro Batezelli
• Support type: Regular Research Grants
• FAPESP's process: 10/14797-0 - Fossil eggs of Crocodyliforms from Upper Cretaceous of Bauru Group, regions of Campina Verde, Minas Gerais State, and Presidente Prudente, São Paulo State
• Grantee: Júlio Cesar de Almeida Marsola
• Support type: Scholarships in Brazil - Master
• FAPESP's process: 14/03825-3 - The origin and rise of dinosaurs in Gondwana (late Triassic - early Jurassic)
• Grantee: Max Cardoso Langer
• Support type: Research Projects - Thematic Grants
• FAPESP's process: 13/11358-3 - The Crocodyliformes OTIC region, evolutive and PALEOEBIOLOGICAL implications
• Grantee: Felipe Chinaglia Montefeltro
• Support type: Scholarships in Brazil - Post-Doctorate