DNA barcoding identification of the macroalgal flora of Tunisia

Tunisia has a key position in the Mediterranean and constitutes a transition area with a rich habitat diversity between eastern and western basins. The latest inventory of marine macrophytes dates back to 1987, updated in 1995. The target of this thesis was to carry on a molecular-assisted alpha taxonomy (MAAT) survey of macroalgae, which allowed to reveal cryptic species, allochthonous introductions and to identify problematic taxa. Twenty-six genetic species of Florideophyceae were resolved, including five new reports, two of which considered as doubtful for the Mediterranean, and two others as alien species. Of the remaining 21, one was an alien, showing cryptic diversity among the Mediterranean reports of this taxon, two revealed cryptic diversity in other geographical regions, five required a taxonomic update and three a nomenclature update. Nine genetic species groups were resolved within the genus Ulva (Chlorophyta), including the non indigenous species Ulva ohnoi, newly reported for Tunisia. The actual picture of the taxonomy of Ulva spp. in the Mediterranean as a whole is far to be clarified and the present data on Tunisian collections aim to be a step towards its clarification. This is the first DNA barcoding study on macroalgae in Tunisia. This paper is useful to add records to the BOLD system catalogue, amplifying the biodiversity knowledge linked to geographical information, and making them freely available for the scientific community. An effective monitoring of the biodiversity changes by means of a quick and accurate tool, such as DNA barcoding, is essential to provide the basis for a correct environmental management.