Haliotis marmorata from Senegal; a sister species of Haliotis tuberculata: Morphological and molecular evidence

Two abalone species were described in Senegal by Linnaeus in 1758: Haliotis tuberculata and Haliotis marmorata. The present study investigates differences at the molecular level by comparing 18S rDNA - ITS1 and mitochondrial sequences, in addition to making a morphological description of 35 OTUs from the Senegalese coast. A comparison was made between the two sympatric sub-species: Haliotis tuberculata tuberculata, present throughout Northern Europe, and H. t. coccinea, present in the Canary Islands and on Northern Atlantic coasts. Although shell morphology cannot be used to easily differentiate Senegalese specimens, the number of open respiratory pores in the shells was significantly lower. Nuclear 18S rDNAs showed 0.6% differences and ITS1 0.37% between H. marmorata and H. tuberculata sub-species. The divergence of the coding genes of mitochondrial DNA ranged from 4.5 to 13.3%, between H. tuberculata and H. marmorata whilst it ranged from 1.2 to 5.5% between H. tuberculata sub-species. These variations are lower for tRNAs. A phylogenetic analysis using three different markers (ITS1, COI and 16S) from Haliotidae revealed a robust cluster for the species complex H. tuberculata and H. marmorata. Seven different haplotypes were found inside the 35 OTUs from Senegal, by using COI, that are unrelated to the defined H. tuberculata sub-species haplotypes. The ancient geographical isolation during the Quaternary period may explain their allopatric speciation. From Our results we consider these two species as sister species but, other studies are necessary to verify their status. (c) 2010 Elsevier Ltd. All rights reserved.