ATIMO VATAE, PANGLAO 2004, PAPUA NIUGINI

The rough pen shell Pinna rudis Linnaeus, 1758 (family Pinnidae) is a mollusc with an Atlantic–Mediterranean distribution, typically inhabiting coarse sandy substrates. Habitat degradation is considered the primary cause of population decline, leading to the designation ‘Vulnerable’ in certain regions. In this study, we conducted a genetic analysis of populations of P. rudis from Cabo Verde and compared them with populations from the Mediterranean and Macaronesia. We based our analysis on two mitochondrial DNA markers, cytochrome oxidase I (COI) and 16S rRNA, and one nuclear marker, 28S rRNA. The results showed a strong genetic structuring among Macaronesia populations, with each island tending to have unique or exclusive haplotypes, though some sharing occurred between islands. We found significant genetic divergence between the population from Cabo Verde and the other sampled population, suggesting that P. rudis is not monotypic, but may include several cryptic species. Bayesian and maximum-likelihood phylogenetic analysis, including all Pinnidae species, indicated that P. rudis from Gorée Island (Senegal) and Baía das Gatas (São Vicente Island) might be undergoing speciation. The high genetic structure found for P. rudis could be influenced by hydrodynamic barriers, local currents and hydrographic isolation, in association with the short larval duration (planktotrophic) reported for this species. Altogether, our findings highlight significant genetic divergence in P. rudis populations, possibly supporting speciation events in the Cabo Verde archipelago among widely distributed taxonomic groups.

BIOPAPUA, CONCALIS, Restreint, EXBODI, INHACA 2011, KARUBENTHOS 2012, PAKAIHI I TE MOANA, Restreint

Molecular data were used to study the diversity of mytilids associated with sunken-woods sampled in the Solomon Islands and discuss the 'wooden steps to deep-sea vent' hypothesis proposed by Distel et al. First, COI data used in a barcoding approach confirm the presence of four distinct species. Analyses of the 18S rDNA and COI dataset then confirmed that these sunken-wood mytilids belonged to a monophyletic group including all species from deep-sea reducing environments. Finally, we analyzed the relationships within this monophyletic group that include the Bathymodiolinae using a COI dataset and a combined analysis of mitochondrial COI and ND4 genes and nuclear rDNA 18S and 28S. Our study supported the 'wooden steps to deep-sea vent' hypothesis: one of the sunken-wood species had a basal position within the Bathymodiolionae, and all described vent and seep mussels included in our analyses were derived taxa within Bathymodiolinae.

SALOMON 2, SANTO 2006