Phylogenetic hypothesis of freshwater crabs of the family Trichodactylidae (Decapoda, Brachyura) in the Neotropical region

• Grant number: 25/00395-2
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: June 01, 2025
• End date: August 31, 2029
• Field of knowledge: Biological Sciences - Zoology - Taxonomy of Recent Groups
• Principal Investigator: Fernando Luis Medina Mantelatto
• Grantee: Tiago Arantes
• 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

Trichodactylidae is a family of freshwater crabs with a wide geographic distribution in the Neotropical region, composed of species with a high degree of endemism. Like other taxa, it has uncertainties regarding its origin and radiation, as well as taxonomic challenges that have resulted in a decline in the frequency of new species descriptions in recent years. This condition raises questions about the reasons behind this trend, whether due to a lack of specialists in the taxon or limited sampling coverage. Species identification and description have traditionally been based on morphological characters; however, molecular tools are now successfully employed alongside morphology to elucidate various aspects of this taxon's diversity. These studies not only contribute to a better understanding of the diversity and evolution of Trichodactylidae but also have important implications for conservation, particularly considering cryptic species, which may be at greater risk of extinction even before being known to science. This thesis project aims to investigate the origin, dispersal routes, and phylogenetic relationships of Trichodactylidae in the Neotropical region, using an integrated approach that combines molecular, morphological, and biogeographical analyses. To achieve the proposed objectives, specimens already deposited in different scientific collections, such as the Crustacean Collection of the Department of Biology (CCDB), other national collections (MZUSP, INPA), and international collections (USNM, NHML, and SMF), will be analyzed. If necessary, new collections will be conducted to supplement the available material. Morphological analysis will involve the examination of the main structural characters described in the specialized literature, comparing them with the specific descriptions of the species. In parallel, the molecular protocol will include the amplification of genetic material from the specimens, followed by purification and sequencing of the molecular markers of interest. The data obtained will be analyzed using computational tools to construct phylogenetic hypotheses, aiming to elucidate the relationships among the genera of Trichodactylidae. (AU)