Evolução do sistema reprodutor masculino e Spermiotaxonomia dos caranguejos-de-galha Cryptochiridae (Thoracotremata, Brachyura)

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 the 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 rrelationship 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 kinship relationships within Cryptochiridae and Thoracotremata, leading us to better understand how evolved these characters within the group.