A mosaic of cryptic species among the family Rajidae: moving from phylogenetics to phylo-transcriptomics

none3Nowadays, the cliché depicting speciation as synonym of change seems to be outdated, since more and more marine species reveal, besides analogous ecological traits, also similar morphological patterns. This condition appears to be particularly widespread among elasmobranchs (Quattro et al., 2006; Griffiths et al., 2010), especially within the monophyletic Raja cluster. The peculiar feature that make this group so interesting is the presence of a remarkable number of cryptic and few non-cryptic species. The evolutionary maintenance of a stable architecture between recently diverged clusters could be ascribed to a paleo-hydrogeographical isolation (Valsecchi et al., 2005; Pasolini et al., 2011; Messinetti, 2013) coupled with the preferential use of the electric sense for communication and camouflage as anti-predatory mechanism. For instance, the siblings Raja polystigma and R. montagui have been taxonomically misidentified for a long time (Frodella et al., submitted). The most striking case is the R. miraletus complex, where a significant variation in mtDNA led to recognize at least three parapatric clades in the Mediterranean, Eastern Atlantic and South African waters (McEachran et al., 1989; Ferrari et al., in preparation). DNA barcoding was a trigger for the identification of cryptic species but, currently, shading light on Rajids’ evolution and understanding the morphological cladogenesis have become a challenge. A first attempt of transcriptome profiling of different skin tissues of these non-model organisms will be carried out in order to investigate which loci are linked to skates patterning and establish how they diverge between cryptic and non-cryptic species. To date, a sampling protocol for downstream RNA analyses was established and applied on nine species collected in the Mediterranean Sea, Eastern Atlantic and South African waters. After RNA libraries construction and sequencing, data analysis will target the identification of a pool of loci likely related to coloration differing between cryptic and non-cryptic taxa.mixedAlice Ferrari; Alessia Cariani; Fausto TintiAlice Ferrari; Alessia Cariani; Fausto Tint