Integrative approach revealing a species complex in the Neotropical freshwater crab Dilocarcinus septemdentatus (Herbst, 1783) (Decapoda: Trichodactylidae) with a description of a new species

Author(s)

Franca, Nielson Felix Caetano ; Magalhaes, Celio ; Mantelatto, Fernando Luis

• Document type: Journal article
• Source: ARTHROPOD SYSTEMATICS & PHYLOGENY; v. 82, p. 21-pg., 2024-05-15.

Abstract

The taxonomic status of the freshwater crab Dilocarcinus septemdentatus (Herbst, 1783) is still not well established. Currently, the main issue involves synonymization with D. spinifer H. Milne Edwards, 1853, based on a variation of the angulation of the gonopod apex. These species are distributed along rivers and lakes in northern South America, with disjunct occurrences in central-west Brazil and Argentina. Due to these inconsistencies, an integrative approach was performed to elucidate these questions, with morphological (including NanoCT-Scan) and molecular analysis (Maximum Likelihood Trees, Bayesian Inference, Genetics Distance Matrix, and Haplotype Network), based on mitochondrial markers COI and 16S rRNA. Both analysis revealed and supported the existence of a species complex under the name of D. septemdentatus. Based on the results obtained, we propose the revalidation of D. spinifer, the description of a new species, and the redescription of D. septemdentatus s. str., with a neotype designation for this species. The hypothesis that this species complex originated in the Pebas System, an extensive mega wetland system that existed along the lowlands of Western Amazonia from late Oligocene to late Miocene (c. 23-11 mya) is discussed. (AU)

• FAPESP's process: 09/54931-0 - Improvement and management of biological specimen collections at the Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo
• Grantee: Carlos Alberto Garofalo
• Support Opportunities: Research Infrastructure Program - Biological specimen collections
• FAPESP's process: 18/13685-5 - Integrative analysis of the Brazilian fauna of decapod crustaceans: taxonomy, phylogenetic systematics, spermiotaxonomy, morphology of post-embryonic development, ecology and conservation
• Grantee: Fernando Luis Medina Mantelatto
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 21/08075-6 - Training of specialized human resources in the molecular taxonomy field: decapod crustaceans as a training model
• Grantee: Fernando Luis Medina Mantelatto
• Support Opportunities: BIOTA-FAPESP Program - Regular Research Grants
• FAPESP's process: 10/50188-8 - Decapod crustaceans: multi-disciplinary characterization of the sea biodiversity of the State of São Paulo (taxonomy, spermiotaxonomy, molecular biology and population dynamics)
• Grantee: Fernando Luis Medina Mantelatto
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants