Disentangling the Taxonomic Status of Caprella penantis sensu stricto (Amphipoda: Caprellidae) Using an Integrative Approach

Abstract

Despite its importance in intertidal and shallow-water marine ecosystems, Caprella penantis continues to be one of the most taxonomically challenging amphipods in the world. A recent molecular study focusing on C. penantis sensu stricto pointed out the existence of three highly divergent lineages, indicating the possible existence of a process of ongoing speciation and, thus, casting doubt on the taxonomic status of this species. In the present study, we used an integrative approach to continue to shed light on the taxonomy and distribution of this caprellid. To this end, we combined morphological and genetic data (COI and 18S) and included, for the first time, populations from its type locality. Our analyses provide strong evidence of the existence of potentially three distinct species, genetically and geographically restricted, within C. penantis sensu stricto, with the distribution of the true C. penantis sensu stricto restricted to the UK (type locality), the northern coast of the Iberian Peninsula, and the Azores. Results show the co-occurrence of two of these species in a locality of northern Portugal and indicate the existence of distinct evolutionary and diversification patterns along the eastern Atlantic region. Overall, our study highlights the use of an integrative approach to properly assess species boundaries and unravel hidden biodiversity in amphipods.

Inventario de Amphipoda (Peracarida: Senticaudata y Amphilochidea) del Río Miño Internacional, Península Ibérica

“…Apart from pioneer European Amphipoda systematic works covering some specific areas like Bate & Westwood (1863) and Lincoln (1979) for British Isles, Sars (1895) and Stephensen (1923aStephensen ( , 1923bStephensen ( , 1931 for Norway, Stebbing (1906) compilation or Chevreux & Fage (1925) work on French amphipods, modern and comprehensive monographs based on local fauna are still far from completion and an enormous amount of work is still needed to meet the requirements of modern taxonomy. Portuguese amphipod fauna remains poorly studied with few dedicated surveys (van Maren, 1975;Marques and Bellan-Santini, 1987, 1990, 1991, 1993Ortiz & Jimeno, 2001;d'Udekem d'Acoz, 2010;Carvalho et al, 2012;Plicanti et al, 2017;Cabezas et al, 2022), despite recent ecological studies (Cunha et al, 1999(Cunha et al, , 2011Pereira et al, 2006;Izquierdo & Guerra-García, 2011;Guerra-García et al, 2012;Martins et al, 2013;Sampaio et al, 2016;Dauvin et al, 2021). In this study we provide an overview on Amphipoda fauna collected on the Minho River estuary (with brief diagnosis, ecological notes, global and Portuguese distributions), belonging to 34 species, in which 23 are new records for the Minho River (including one new record for Portugal).…”