Integrative approach revealing a species complex in the Neotropical freshwater crab Dilocarcinus septemdentatus with a description of a new species

• Published in: Arthropod systematics & phylogeny Vol. 82; no. 1–2; pp. 385 - 405
• Main Authors: Felix Caetano França, Nielson, Magalhães, Célio, Mantelatto, Fernando Luis
• Format: Journal Article
• Language: English
• Published: Dresden Pensoft Publishers 15-05-2024; Senckenberg Gesellschaft für Naturforschung
• Subjects: Bats; Bayesian analysis; Biodiversity; Crustaceans; Discovery and exploration; Fresh water; Genes; Haplotypes; Miocene; Morphology; Museums; New species; Oligocene; Physical characteristics; rRNA 16S; Taxonomy; Brazil; United Kingdom; Argentina; Netherlands; French Guiana; Germany; United States > US
• ISSN: 1863-7221; 1864-8312
• DOI: 10.3897/asp.82.e115268

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. Keywords: CT-scan, DNA barcode, Haplotype diversity, Molecular systematics, Taxonomy