Hidden Mediterranean biodiversity: molecular evidence for a cryptic species complex within the reef building vermetid gastropod Dendropoma petraeum (Mollusca: Caenogastropoda)

Abstract

The reef building vermetid gastropod Dendropoma petraeum inhabits the warmest waters of the Mediterranean Sea and is considered a threatened marine species. The aim of this study was to characterize its genetic structure throughout its whole distribution range using mitochondrial and nuclear sequence data. Because of its sessile adult lifestyle and lack of a pelagic larval stage, we expected a markedly subdivided population structure with limited levels of gene flow. Fragments of the mitochondrial genes cytochrome c oxidase subunit I (COI) and 16S rRNA (16S), were sequenced, along with the nuclear ribosomal cluster (internal transcribed spacer; ITS) in specimens from 18 localities. Our analyses identified four highly distinct phylogroups separated by a mean divergence of > 14% according to the COI sequence data or > 9% according to 16S, but differing only slightly in morphology. The nuclear data (ITS) indicated a lower substitution rate (divergence among groups of around 1%). These large genetic distances among the four lineages clearly point to the existence of a cryptic species complex within D. petraeum comprising at least four species. Differences in the characteristics of intracapsular larval development and protoconch were also detected among these lineages. The allopatric distribution of these cryptic species supports a predominantly vicariant-based cladogenetic pattern for the genus Dendropoma in the Mediterranean.

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.…”

A new species of Novastoa Finlay, 1926 (Mollusca: Gastropoda: Vermetidae) from coral reefs of the Pacific Ocean

“…In the few cases in which population-level molecular data are available for vermetids (i.e., Faucci 2007;Calvo et al 2009Calvo et al , 2015Golding et al 2014;Templado et al 2016), a high level of cryptic diversity has been documented even at much smaller scales. The best-studied example is a Mediterranean reefforming vermetid, usually called Dendropoma petraeum (Monterosato, 1884), which is also one of the most studied vermetids due to its intrinsic potential use as sea level indicator (see Schiaparelli et al 2006 and references therein).…”

“…The best-studied example is a Mediterranean reefforming vermetid, usually called Dendropoma petraeum (Monterosato, 1884), which is also one of the most studied vermetids due to its intrinsic potential use as sea level indicator (see Schiaparelli et al 2006 and references therein). The nominal species was recently shown (Calvo et al 2009;Templado et al 2016) to be a complex of four species.…”

Vermetid reefs in the Mediterranean Sea as archives of sea-level and surface temperature changes

“…A typical vermetid reef is the outcome of complex synergistic building activity by the vermetid mollusc Dendropoma (Novastoa) petraeum (Monterosato, 1892) and the encrusting red alga In a recent article, Calvo et al [10] genetically characterised D. petraeum throughout its entire distribution range in the Mediterranean Sea. Data from different sites indicate the existence of a cryptic species complex within D. petraeum, comprising at least four species.…”