Combined multigene and morphological analysis reveals lineage-specific diversification of the neotropical freshwater crabs of the genus Fredius Pretzmann, 1967 (Brachyura, Pseudothelphusidae)

Abstract

The pseudothelphusid freshwater crabs of the genus Fredius Pretzmann, 1967 are distributed throughout northern South America and currently include 15 species. We investigated the phylogenetic relationship within the genus using mitochondrial (16S rRNA and COI) and nuclear (H3) genes for most of its representatives. Our set of molecular results (10 species) indicate that Fredius, as currently recovered, is formed by species included in three main lineages. In addition, the results revealed inconsistencies in the morphological identification of some species against the molecular positioning in the topology and suggested the presence of cryptic species, which must be morphologically reanalysed.

Key words:

• Amazon region
• cryptic species
• Decapoda
• Kingsleyinae
• nanoCT scan
• systematics

Acknowledgements

This research is part of a multidisciplinary long-term project aiming to access the decapod freshwater biodiversity with support provided by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) (Projetos Temáticos Biota 2010/50188-8 and INTERCRUSTA 2019/13685-5; Coleções Científicas 2009/54931-0 and PROTAX 2016/50376-5) to FLM. We also thank additional support from the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) – Código de Financiamento 001 (2005/2014-23038.004308/201414, Ciências do Mar II) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq – Brazil) (PIBIC 151788/2015-4 and 144787/2016-4 to SRA; PQ 308968/2018-2 to CM; PQ 302253/2019-0 to FLM). The Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP), Universidade de São Paulo (USP), and Instituto Nacional de Pesquisas da Amazônia (INPA) provided logistic support. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We are grateful to the National Museum of Natural History (NMNH), Instituto Nacional de Pesquisas da Amazônia (INPA) and Museu de Zoologia da Universidade de São Paulo (MZUSP) and respective collection curators for specimens donations and loans and to many colleagues and friends (Allysson Pinheiro, Ana Francisca Tamburus, Daniel Cavallari, Eduardo Almeida, Flávio Bockmann, João Pantaleão, Joana d’Arc Pinto, Marcos Tavares, Rafael Robles, and all other members of LBSC) for help in field collections, for lending us material from their collections, for some analysis and for critical discussions, corrections and suggestions during the research. CM thanks his INPA’s colleagues Douglas A. Bastos, Francisco F. Xavier, Jansen Zuanon, Marcio L. Oliveira, and Thiago Mahlmann for making available the freshwater crabs collected during the Serra da Mocidade expedition; Victor Py-Danuel (in memoriam) and Ulysses C. Barbosa are especially acknowledged for the substantial collection of Fredius specimens made during their entomological research expeditions into the Yanomami Indigenous Reserves in northern Brazil that made this study possible. The collections of species conducted in this study complied with current applicable state and federal laws of Brazil (permanent license to FLM for collection of Zoological Material No. 11777-1 MMA/IBAMA/SISBIO). Thanks are also due to anonymous reviewers for useful comments during the review process.

Competing interests

The authors declare there are no competing interests.

Associate Editor: Polly Hayes