Decoding the genetic puzzle of Raja miraletus species complex in the Central-Western Africa

The Raja miraletus species complex represents an emblematic case of cryptic speciation in elasmobranchs. Taxa within this complex are characterised by strong morphological similarity but also by significant genetic divergence, especially along the Atlantic coast of Africa. Recent taxonomic revisions have led to the identification of several species and lineages not yet formally described, making it necessary to conduct an in-depth assessment of the genetic structure of the populations located along West Africa. The genetic variability of these populations was analysed using seven microsatellite loci (Simple Sequence Repeats, or SSRs), and a total of 149 samples from ten geographical areas distributed from Morocco to South Africa were genotyped. The results obtained highlighted a strong genetic structuring among sampled populations, showing the presence of several distinct genetic clusters along the West African coastline. These clusters were also confirmed by multivariate analyses, suggesting a possible influence of oceanographic barriers in the differentiation of these populations. Overall, this study provides new insights into the phylogeographic structure of the Raja miraletus species complex and highlights the importance of genetic approaches for understanding biodiversity and population connectivity in morphologically conserved marine taxa.