New frontiers in the fossil record of southwestern Amazonia

• Grant number: 25/01077-4
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2025
• End date: March 31, 2028
• Field of knowledge: Biological Sciences - Zoology - Paleozoology
• Principal Investigator: Annie Schmaltz Hsiou
• Grantee: Annie Schmaltz Hsiou
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated researchers: Alessandro Batezelli ; Carlos Dapolito Júnior ; Daniel de Simão Oliveira ; Edson Guilherme da Silva ; Fellipe Pereira Muniz ; Francisco Ricardo Negri ; Gabriel de Souza Ferreira ; Gustavo Adolfo Ballen Chaparro ; Ighor Dienes Mendes ; Lidiane de Asevedo Silva ; Pedro Lorena Godoy ; Sidnei mateus ; Thayara Silveira Carrasco ; Thiago Silva Loboda ; Wilfried Klein

Abstract

The fossil diversity of the southwestern Amazonia region has been known for more than a century and a half. It includes well-established fossiliferous sites along riverbanks and the margins of major regional rivers, particularly in the State of Acre. However, many areas remain unexplored, with previous indications suggesting they could hold immense potential for paleontological records, which would provide a more detailed understanding of the paleofauna of the region during the Miocene epoch (from 23 to 5 million years ago). This epoch is known for its rich aquatic and terrestrial fauna and for being the cradle of various Amazonian lineages. Thus, understanding this geological interval better allows us to comprehend how biodiversity in Amazonia was formed. Significant environmental changes at the end of the Miocene, related to Andean uplift, climate changes, and the formation of the current river basin, caused extinctions and the emergence of new environments. Science needs to understand the timing and dynamics of these processes better. The goal of the current proposal is to conduct expeditions to lesser-explored and less-known rivers in more remote localities for the systematic prospecting and collection of fossils, as well as the description of rock outcrops and the collection of samples for geochronological dating using absolute and biostratigraphic methods. The results obtained will be analyzed in terms of the taxonomic identity of each fossil, isotopic geochemistry for paleodiet and paleoenvironment studies, and 3D scanning to create an open virtual database for research and scientific dissemination. The proposal also aims to engage residents ("ribeirinhos" and indigenous peoples) who possess knowledge of fossiliferous localities and have acted as sources, providing them and their communities with recognition and training on preserving regional paleontological heritage. (AU)