Evolution of the Male Reproductive System and Spermiotaxonomy of the gall-crabs Cryptochiridae (Thoracotremata, Brachyura)

• Grant number: 24/03821-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Effective date (Start): May 01, 2024
• Effective date (End): September 30, 2025
• Field of knowledge: Biological Sciences - Morphology - Histology
• Principal Investigator: Fernando Jose Zara
• Grantee: Gisele Rodrigues Tiseo
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , 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

The gall crabs belonging to the Family Cryptochiridae constitute a unique cryptic and little-known group of obligate symbionts of scleractinian corals (Anthozoa, Cnidaria). In Brazil, even with unique species making up the important national biodiversity (e.g. Opecarcinus hypostegus, Troglocarcinus corallicola, Troglocarcinus hirsutus and Kroppcarcinus siderastreicola) such associated fauna has not been the target of much research. Data on the reproductive biology of the group are scarce, with no record of description of the morphology of the male reproductive system and sperm ultrastructure. Based on molecular data, even with the monophyly of Cryptochiridae within Thoracotremata, there is no consensus on the phylogenetic relationship between other representatives of related superfamilies (e.g. Cryptochiroidea, Grapsoidea, Pinnotheroidea and Ocypodoidea). Within this problem, the main objective of this project is to answer the question of how the male reproductive system and spermiotaxonomy evolve within the Brazilian representatives of Cryptochiridae, highlighting the need to search for effective and informative morphological characters that help to elucidate and resolve the history evolution of the group at the species, genus and family level. To this end, we will characterize the morphology of the reproductive system and the spermiotaxonomy of the group through computed microtomography and light, interdifferential phase contrast (DIC) and transmission microscopies. Subsequently, homology hypotheses will be tested using the reconstruction of ancestral character states, investigating the concatenated evolution of the aforementioned characteristics. Additionally, the comparative analysis of the morphologies of both, the male reproductive system, and the sperm, linked to the results of molecular data from other subprojects, can help in solving problems of phylogenetic relationships within Cryptochiridae and Thoracotremata, leading us to better understand how evolved these characters within the group.