Species delimitation of neotropical Characins (Stevardiinae): Implications for taxonomy of complex groups

Abstract

Accurate species delimitation is crucial for studies of phylogeny, phylogeography, ecology, conservation and biogeography. The limits of species and genera in the Characidae family are controversial due to its uncertain phylogenetic relationships, high level of morphological homoplasy and the use of ambiguous morphological characters for descriptions. Here we establish species boundaries for Bryconamericus , Hemibrycon , Knodus and Eretmobrycon (Stevardiinae: Characidae), previously diagnosed with morphology, using three different barcoding approaches (GMYC, PTP, ABGD). Results revealed that species delimitation was successful by the use of a single-gene approach and by following a workflow in the context of integrative taxonomy, making evident problems and mistakes in the cataloging of Characidae species. Hence, it was possible to infer boundaries at genus level for clusters in the trees (GMYC and PTP) and automatic partitions (ABGD) which were consistent with some of recent taxonomic changes proposed in Characidae. We found that discordance cases between methods were linked to limitations of the methods and associated to putative species cluster closely related, some historically problematic in their diagnosis and identification. Furthermore, we suggested taxonomic changes and possibly new species, revealing a high degree of hidden diversity. Finally, we propose a workflow as a fast, accurate and objective way to delimit species from mitochondrial DNA sequences and to help clarify the classification of this group.

Museomics of tree squirrels: a dense taxon sampling of mitogenomes reveals hidden diversity, phenotypic convergence, and the need of a taxonomic overhaul

“…Several studies have employed molecular species delimitation methods either as a standalone tool or as part of an integrative approach to delimit species [60][61][62]. Here, we advocate for the use of molecular species delimitation methods along with other sources of evidence, to avoid misleading species delimitation due to theoretical and/or methodological shortfalls (as exemplified above; see also [57][58][59]).…”

Quantifying shortfalls in the knowledge on Neotropical Auchenipteridae fishes

“…In this context, many Neotropical fish families have been revised through studies focused on delimitating species by molecular techniques (e.g. Characidae—García‐Melo et al., 2019; Curimatidae—Melo & Oliveira, 2017; Loricariidae—Roxo, Ochoa, Costa‐Silva, & Oliveira, 2015). Therefore, the noteworthy scarcity of species delimitations from genetic sequences in Auchenipteridae (with the exceptions of Calegari et al., 2019; Cooke, Chao, & Beheregaray, 2012; Hashimoto, Py‐Daniel, & Batista, 2020) is likely to result in the description of large numbers of new species with the progressive implementation of molecular techniques.…”

The unknown diversity of the genus Characidium (Characiformes: Crenuchidae) in the Chocó biogeographic region, Colombian Andes: Two new species supported by morphological and molecular data

“…Using a phylogenetic tree of the COI gene built‐in RAxML HPC2 on XSEDE v8.2.10 (Stamatakis, 2014) implemented in the CIPRES portal (Miller et al ., 2010), the bPTP model was run in the web portal http://species.h-its.org/ptp/ (Zhang et al ., 2013). The three variations of the molecular species delimitation methods (GMYC, ABGD and bPTP) were evaluated following an iterative process of comparison to define the operational taxonomical unit (OTU; García‐Melo et al ., 2019), and the molecular delimitation was accepted when all or the majority of the consensus methods recovered the OTUs as distinct units.…”