Morphological and genetic study of the genus Cymodocea K.D. König (1805) on Tunisian coasts.
The presence along the Tunisian coasts of different morphological and anatomical Cymodocea specimens suggest the presence of different species while the Mediterranean is threatened by the introduction of a great number of aliens. So, in order to survey any introduction of Cymodocea alien species, we aimed in this work to verify (i) the identity of the new forms and (ii) to evaluate the genetic diversity of the Tunisian Cymodocea populations and (iii) the validity of the existing identification keys. Samples were collected from four stations situated in two regions of the Tunisian coasts located in the eastern Mediterranean basin. We measured on mature leaves the biometric parameters (number of cross veins, width of the apex, absence of teeth on the apex margins and shape of apices). Three chloroplast DNA barcoding was used to discriminate taxonomically between Cymodocea populations. Biometrics parameters leaded to distinguish three Cymodocea nodosa morphotype wish are described here for the first time. However, the DNA markers rbcL, matK and trnHpsbA has not allowed to discriminate taxonomically between the morphological new types. The observed morphological variations might be phenotypical variations induced by different ecological conditions or genetic specific characters that can't be detected by the used markers.