Macroevolution and biogeography of Neotropical freshwater crabs of the superfamilies Pseudothelphusoidea Ortmann, 1893 and Trichodactyloidea H. Milne Edwards, 1853 (Brachyura, Heterotremata)

• Grant number: 24/11643-4
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: March 01, 2025
• End date: July 31, 2029
• Field of knowledge: Biological Sciences - Zoology - Taxonomy of Recent Groups
• Principal Investigator: Fernando Luis Medina Mantelatto
• Grantee: Felipe Cesar Balbino Santos
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 18/13685-5 - Integrative analysis of the Brazilian fauna of decapod crustaceans: taxonomy, phylogenetic systematics, spermiotaxonomy, morphology of post-embryonic development, ecology and conservation, AP.BTA.TEM

Abstract

Freshwater crabs make up a considerable part of Brachyura's diversity, and taxonomic classifications at broader levels have recently undergone several adjustments, but still without a consensus on the phylogenetic positioning of their representatives within Eubrachyura. The superfamilies from the Neotropical region, Pseudothelphusoidea and Trichodactyloidea, follow this profile of phylogenetic uncertainties. Three hypotheses for the emergence of these groups have already been proposed, one arguing that all large groups emerged separately; another stating that at least a large part of freshwater crabs are descendants of an ancestral freshwater population that gave rise to large groups after the fragmentation of the continents; and the last suggests that freshwater crab superfamilies form a monophyletic group, but the groups invaded freshwater separately. Therefore, with great uncertainties regarding the phylogeny and biogeography of these groups, and due to the scarce fossil record, little is known about their evolution, particularly for groups from the Neotropics. Thus, the present project proposes, in an unprecedented and innovative way, to use molecular tools, such as multigene phylogenetic analyzes and phylogenomics, to elucidate the phylogenetic relationships between these groups, especially the taxa distributed on the American continent. With the construction of new phylogenetic hypotheses, the objective is also to map, through molecular clocks and ancestral distribution reconstruction analyses, the emergence and irradiation of Neotropical groups, using the fossil record as support for the proposed analyses.