Strong population structure and shallow mitochondrial phylogeny in the banded guitarfish, Zapteryx exasperata (Jordan y Gilbert, 1880) from the northern Mexican Pacific

The northern Mexican Pacific (NMP), the Gulf of California (GC), and Baja California have been recognized as an ecological and evolutionarily dynamic region having experienced significant tectonic and climatic changes leading to the diversification of terrestrial and marine biotas. Zapteryx exasperata is a predominant ray caught in the artisanal fisheries of the NMP. Morphometric and reproductive differences between rays from the GC and the Pacific Coast of Baja California (PCBC) regions suggest the presence of distinct populations. We investigate whether this distinction correlates with differences in genetic diversity and differentiation using sequences of the mitochondrial ND2 gene and the non-coding control region (CR) in 63 specimens. Contrary to our expectations, ND2 bore significantly more diversity (h = 0.76) than CR (h = 0.39). Geographic patterns of diversity of CR were opposite to those of ND2, with GC being significantly less (ND2) and more (CR) diverse than PCBC. The divers...