PALEONEUROANATOMY OF TWO CAIMANINES (ALLIGATOROIDEA, CAIMANINAE) FROM THE BRAZILIAN PROTO-AMAZONIA

• Grant number: 25/07350-4
• Support Opportunities: Scholarships in Brazil - Master
• Start date: August 01, 2025
• End date: July 31, 2027
• Field of knowledge: Biological Sciences - Zoology - Paleozoology
• Principal Investigator: Annie Schmaltz Hsiou
• Grantee: Lucas Hariel Martins de Lima
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 25/01077-4 - New frontiers in the fossil record of southwestern Amazonia, AP.R

Abstract

South American caimanines exhibit a vast richness of species and morphological diversity among crocodilians, especially in fossil representatives. Among the extinct taxa, Mourasuchus and Acresuchus stand out due to their significant morphological disparities compared to extant species. These taxa thrived in the lacustrine and fluvial ecosystems of the proto-Amazonia, particularly within the Pebas and Acre systems, favored by the pronounced increase in temperature and humidity during the Miocene.Beyond studies in taxonomy, systematics, and the evolution of fossil crocodilians, the neuroanatomical investigation of their cranial cavities offers great potential for a deeper understanding of their somatosensory capabilities, indicating adaptations to specific habitats and their paleobiology. Interest in such studies has grown in recent decades, especially with the advancement of imaging analysis methods such as Computed Tomography, which pose no risk of damaging specimens due to their non-invasive nature, thus preserving the integrity of the analyzed materials.This study, therefore, aims to contribute to the understanding of the evolution and diversification of Miocene caimanines from the Brazilian proto-Amazonia by describing and analyzing the neuroanatomical structures of Mourasuchus and Acresuchus, through the creation of digital endocasts of their cranial cavities.