Reappraisal of the hyperdiverse

Abstract

Morphologically similar species are often overlooked but molecular techniques have been effective in signalling potential hidden diversity, boosting the documentation of unique evolutionary lineages and ecological diversity. Platynereis dumerilii and Platynereis massiliensis are part of a recognised species complex, where differences in the reproductive biology have mainly been highlighted to date. Analyses of DNA sequence data (COI, 16S rDNA and D2 region of the 28S rDNA) of populations of the apparent morphotype of P. dumerilii obtained from a broader sampling area along European marine waters, including the Azores and Webbnesia islands (Madeira and Canaries), provided compelling evidence for the existence of at least 10 divergent evolutionary lineages. Complementing the genetic data, morphological observations of the better represented lineages revealed two major groups with distinctive paragnath patterns. Two new Platynereis species were erected: P. nunezi sp. nov., widespread in the Azores and Webbnesia islands, and P. jourdei sp. nov., restricted to the western Mediterranean. The new combination P. agilis is also proposed for Nereis agilis, previously unaccepted for one of the lineages present both in the Northeast Atlantic and western Mediterranean. Platynereis dumerilii is redescribed based on topotypic material. However, uncertainty in the identity of P. massiliensis due to the original brief description and the absence of type and topotypic material prevents the unequivocal assignment to the lineage assumed in this and previous studies. The remaining five lineages are represented by only a few small specimens with morphological features poorly preserved and were therefore not described in this study. ZooBank: urn:lsid:zoobank.org:pub:50079615-85E5-447E-BDD7-21E81C2A6F4D

Two new records and description of a new Perinereis (Annelida, Nereididae) species for the Saudi Arabian Red Sea region

“…1A ), despite being divergent lineages, with genetic distances that are in the range used for delimitating polychaete species (i.e., Kvist 2016 ; Lobo et al 2016 ; Nygren et al 2018 ). This situation, together with the absence or subtle morphological differences previously overlooked, resembles cryptic lineages within a species complex ( Teixeira et al 2022b , 2023 ), and further sampling efforts between the Red Sea to the Indo-Pacific region are needed to assess this.…”

“…For measuring length of dorsal ligules, not only the lengths of the tips were considered, but the proximal part of the ligules was also included (e.g., Conde-Vela and Salazar-Vallejo 2015 ; Villalobos-Guerrero and Carrera-Parra 2015 ; Teixeira et al 2022b ). Like Hutchings et al (1991) , a specimen is described as having a greatly expanded dorsal notopodial ligule posteriorly only if the dorsal ligule is more than two times as long as the ventral ligule.…”

“…Thanks to molecular data, it is now easier to screen for potential new species with apparent similar morphotypes. Recent evidence comparing populations from different regions has shown that when specimens differ genetically, further analysis of the diagnostic morphological features often leads to the recognition of distinct features that were previously overlooked (i.e., Sampértegui et al 2013 ; Teixeira et al 2022b ). A recent review on meiofauna ( Cerca et al 2018 ) and recent polychaete studies (i.e., Abe et al 2019 ; Tilic et al 2019 ; Martin et al 2020 ), including from Nereididae ( Glasby et al 2013 ; Sampieri et al 2021 ; Teixeira et al 2022a , b ) also demonstrate that cryptic and pseudo-cryptic species often have geographically restricted distributions, with the range of cryptic species being smaller than the parent morphospecies.…”

The Nereididae (Annelida) – diagnoses, descriptions, and a key to the genera

“…Taxonomic research on Nereididae is active, with nearly 100 papers published in the past decade, and the family currently comprises 45 genera and 719 species ( Read and Fauchald 2023 ). Prominent among recent studies are investigations using molecular evidence leading to discovery of cryptic species ( Glasby et al 2013 ; Villalobos-Guerrero and Bakken 2018 ; Tosuji et al 2019 ; Teixeira et al 2022a , 2022b ) and new phylogenetic hypotheses ( Tosuji et al 2018 ; Alves et al 2020 , 2023 ; Villalobos-Guerrero et al 2022b ). The past decade has also seen description of 40 new species, revision of eight genera and a review of the diversity, biology, anatomy, and ecology of the family Bakken et al (2022) .…”

A new species of Perinereis Kinberg, 1865 (Annelida: Nereididae) from the Western Mediterranean Sea revealed by morphological and molecular approaches

“…The combined use of morphology and DNA evidence is a powerful tool for disentangling nereidid species complexes or discovering previously unknown species (Glasby et al, 2013;Sampértegui et al, 2013;Kara et al, 2020;Tosuji et al, 2019;Drennan et al, 2021;Wang et al, 2021;Teixeira et al, 2022). In particular, the mitochondrial cytochrome c oxidase I (COI) gene has been used to explain the interspecific relationships between nereidid species and their phylogeographic relationships; hence, used to analyze population structure, evolutionary relatedness, and delimitation of species (e.g., Park & Kim, 2007;2017;Villalobos-Guerrero & Carrera-Parra, 2015;Kara et al, 2018;Villalobos-Guerrero et al, 2022).…”