Molecular data reveal cryptic lineages within the northeastern Atlantic and Mediterranean small mussel drills of theOcinebrina edwardsiicomplex (Mollusca: Gastropoda: Muricidae)

Abstract

We used a molecular phylogenetic approach to investigate species delimitations and diversification in the mussel drills of the Ocinebrina edwardsii complex by means of a combination of nuclear (internal transcribed spacer 2, ITS2) and mitochondrial [cytochrome oxidase subunit I (COI) and 16S] sequences. Our sample included 243 specimens ascribed to seven currently accepted species from 51 sites. Five of the samples were from either the type locality of a nominal species or a close nearby locality (O. edwardsii from Corsica, O. carmelae and O. piantonii from the Kerkennah Islands, O. hispidula from the Gulf of Gabès and O. leukos from the Canary Islands), one from the inferred original locality (O. ingloria from Venice Lagoon), and specimens assigned in the recent literature to O. nicolai. We used a combination of distance‐ and tree‐based species delimitation methods to identify Molecular Operational Taxonomic Units (MOTUs) to compare with the a priori species identifications. The consensus tree obtained by BEAST on the COI alignment allows the recognition of several distinct clades supported by the three species delimitation methods employed. The eight‐MOTUs scenario, shared by the Automatic Barcode Gap Discovery (ABGD) and Generalized Mixed Yule‐Coalescent (GMYC) methods, comprises the following major clades: clade A contains the south Tunisian species Ocinebrina piantonii Cecalupo, Buzzurro & Mariani from which the sympatric taxon O. carmelae Cecalupo, Buzzurro & Mariani (new synonym) cannot be separated; clades B and C bring together all populations from the Aegean Sea and some from the Ionian Sea, respectively; clade D groups, on the one hand, the south Tunisian samples morphologically assigned to O. hispidula Pallary and, on the other, Atlantic and Alboran Sea samples (including the Canarian taxon O. leukos Houart); clade E includes a sample from the type locality of O. edwardsii and several samples from the Tyrrhenian Sea; clades F and G correspond to a few samples from the Venice Lagoon and the Tyrrhenian Sea, respectively; clade H groups the bulk of samples from the Adriatic Sea, including samples from the Venice Lagoon morphologically identified as Ocinebrina ingloria (Crosse), and some from the Ionian Sea. No final conclusions could be reached to reconcile the currently recognized morphological taxa with the clades suggested by the COI data. The geographical structure proposed by the mitochondrial markers is similar to that found in other marine invertebrates and partially corresponds to the species defined by shell characters. We propose here a framework for the revision of the Ocinebrina edwardsii species complex, suggesting a geographical pattern for the diversification of this group in the studied area. © 2013 The Linnean Society of London

Cryptic diversity in Mediterranean gastropods of the genus <em>Aplus</em> (Neogastropoda: Buccinidae)

“…The relatively large genetic divergence among the species of this complex (>10%), notwithstanding their morphological similarity (and the frequently overlapping morphological variation) is not infrequent in Mediterranean gastropods. Similar patterns have been recently observed in the sessile vermetids of the genus Dendropoma (Calvo et al 2009(Calvo et al , 2015 and in the small muricids of the genus Ocinebrina (Barco et al 2013). The fossil history of this complex is documented by a relatively large record (Brunetti and Della Bella 2014), which would be crucial to date nodes of molecular phylogenetic hypotheses and then infer biogeographical dynamics.…”

“…The relative congruence between the species hypotheses defined with ABGD and the morphological and geographical data is a further support to the claim that ABGD can be used as a good proxy for species delimitation in gastropods when only molecular data are available (Puillandre et al 2012, Barco et al 2013, Prockow et al 2013. Seven species hypotheses were eventually retained, corresponding to lineages that are divergent and reciprocally monophyletic, thus satisfying two of the criteria of species delimitation derived from the lineages species concept (Barberousse and Samadi 2010).…”

“…The fossil history of this complex is documented by a relatively large record (Brunetti and Della Bella 2014), which would be crucial to date nodes of molecular phylogenetic hypotheses and then infer biogeographical dynamics. However, it is here highlighted that, similar to what occurs with the small mussel drills Ocinebrina (Barco et al 2013), classification of fossil shells of Aplus might underestimate actual diversity and probably requires more sophisticated tools (e.g. morphometrics) to disentangle their actual variation.…”

Cryptic lineages and high population genetic structure in the exploited marine snail Hexaplex trunculus (Gastropoda: Muricidae)

“…This divergence estimate of ~5 Mya is compatible with the end of the Messinian salinity crisis, during which the Mediterranean basin was split into several sub-basins with varying salinity, and may have led to allopatric divergence (eventually speciation) (Sabelli & Taviani, 2014;Calvo et al, 2015). Lineages with distinct or allopatric geographic distributions were reported in other Mediterranean gastropods with a short larval phase, as in the muricid species complex Ocinebrina edwardsii (Barco et al, 2013) and the vermetid Dendropoma petraeum (Calvo et al, 2009(Calvo et al, , 2015. As for H. trunculus, their distribution also spanned the eastern Atlantic coasts and their history was probably similar.…”

Shallow water sea slugs (Gastropoda: Heterobranchia) from the northwestern coast of the Sea of Japan, north of Peter the Great Bay, Russia

“…It is commonly used for species delimitation analyses, including the latest works on molluscan taxa (Jörger et al, 2012; Barco et al, 2013; Krug et al, 2013; Ekimova et al, 2015; Katugin et al, 2015). The ABGD program is available at the web-site http://wwwabi.snv.jussieu.fr/public/abgd/abgdweb.html.…”