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- The taxonomic status of some Atlanto-Mediterranean species in the subgenus Holothuria (Echinodermata: Holothuroidea: Holothuriidae) based on molecular evidencePublication . Borrero-Pérez, Giomar Helena; Pérez-Ruzafa, Angel; Marcos, Concepción; González-Wangüemert, MercedesMolecular and morphological data were used to evaluate the taxonomic status of the species Holothuria tubulosa Gmelin, 1790, Holothuria stellati Delle Chiaje, 1823, Holothuria mammata Grube, 1840, and Holothuria dakarensis Panning, 1939, belonging to the nominate subgenus Holothuria (Holothuria) (family Holothuriidae) from the Mediterranean Sea and Atlantic Ocean. A 16S rRNA marker distinguished three well-supported clades with clear genetic differentiation amongst them. The morphometric characters, although they reflected the clades, showed great variability, and some specimens from different clades overlapped. The morphological data and the literature suggest that the clades correspond to H. dakarensis (from Cape Verde Islands), H. mammata (from the Atlanto- Mediterranean area) and H. tubulosa (from the Mediterranean Sea). Holothuria stellati is considered here to be a junior subjective synonym of H. tubulosa. Great morphological intraspecific variation within H. tubulosa and H. mammata explains the confusion in the literature. Holothuria tubulosa includes specimens with distinctive ossicles, but others are similar to H. mammata. In these cases, the presence or absence of Cuvierian tubules proved a reliable indicator to the identity of these species; unfortunately this character is difficult to assess in preserved material. According to the results of discriminant analysis we propose a set of ossicle morphometric variables that permit the optimum assignation of individuals to the clades. Our results present a new perspective on the taxonomic status of species in Holothuria (Holothuria), and show how a molecular approach, combined with a morphological approach, can solve taxonomic problems.
- Molecular systematics of the genus Holothuria in the Mediterranean and Northeastern Atlantic and a molecular clock for the diversification of the Holothuriidae (Echinodermata: Holothuroidea)Publication . Borrero-Pérez, Giomar Helena; Gómez-Zurita, Jesús; González-Wangüemert, Mercedes; Marcos, Concepción; Pérez-Ruzafa, AngelThis work investigates the systematics of the genus Holothuria in the Mediterranean Sea and Northeastern Atlantic in the light of a wider molecular phylogenetic hypothesis of Holothuriidae, and it also provides a time-scale for the family diversification using mitochondrial markers and the molecular clock hypothesis. The subgenera Holothuria and Roweothuria are retrieved as paraphyletic. At least four separate lineages, with quite different time frameworks were identified. There are at least three species with an apparent long evolutionary history, H. forskali, H. sanctori and H. impatiens and six species belonging to Holothuria, Roweothuria and Vaneyothuria, which have diverged relatively recently.