@article {9, title = {Molecular phylogeny of land and freshwater planarians (Tricladida, Platyhelminthes): from freshwater to land and back}, journal = {Molecular Phylogenetics and Evolution}, volume = {47}, number = {2}, year = {2008}, month = {05/2008}, pages = {555-568}, chapter = {555}, abstract = {

The suborder Tricladida (phylum Platyhelminthes) comprises the well-known free-living flatworms, taxonomically grouped into three infraorders according to their ecology: Maricola (marine planarians), Paludicola (freshwater planarians), and Terricola (land planarians). Molecular analyses have demonstrated that the Paludicola are paraphyletic, the Terricola being the sister group of one of the three paludicolan families, the Dugesiidae. However, neither 18S rDNA nor COI based trees have been able to resolve the relationships among species of Terricola and Dugesiidae, particularly the monophyly of Terricola. Here, we present new molecular data including sequences of nuclear genes (18S rDNA, 28S rDNA) and a mitochondrial gene (COI) of a wider sample of dugesiid and terricolan species. The new sequences have been analyzed, together with those previously obtained, in independent and concatenated analyses using maximum likelihood and bayesian methods. The results show that, although some parts of the trees remain poorly resolved, they support a monophyletic origin for Terricola followed by a likely return of some species to freshwater habitats. Relationships within the monophyletic group of Dugesiidae are clearly resolved, and relationships among some terricolan subfamilies are also clearly established and point to the need for a thorough revision of Terricola taxonomy.

}, doi = {10.1016/j.ympev.2008.01.032}, url = {http://www.sciencedirect.com/science/article/pii/S1055790308000390}, author = {Marta {\'A}lvarez-Presas and Jaume Bagu{\~n}{\`a} and Marta Riutort} } @article {18, title = {Molecular barcoding and phylogeography of sexual and asexual freshwater planarians of the genus Dugesia in the Western Mediterranean (Platyhelminthes, Tricladida, Dugesiidae).}, journal = {Molecular Phylogenetics and Evolution}, volume = {52}, number = {3}, year = {2009}, month = {09/2009}, pages = {835-845}, chapter = {835}, abstract = {

Planarians of the genus Dugesia have a worldwide distribution with high species diversity in the Mediterranean area. In this area, populations with a triploid karyotype that reproduce by fissiparity are exceptionally frequent, outnumbering the sexual populations. This situation poses interesting questions, such as the age of these asexual lineages, whether they all belong to the same species or whether the triploidization event is recurrent, and what factors (climatic, geographical, historical...) explain the prevalence of these asexual forms. However, asexual populations cannot be assigned to a species due to the lack of copulatory apparatus - the main structure used in species identification. In this study, we have developed a DNA barcoding method, based on COI and ITS-1 sequences, which allows the assignment of the fissiparous forms to sexual species. At the same time, phylogenetic analysis from species of the western Mediterranean have unveiled the presence of species with highly differentiated populations alongside species with a wide distribution and almost no genetic variation. The roles of habitat instability, dispersal capacity and human activities are briefly discussed.

}, doi = {10.1016/j.ympev.2009.04.022}, author = {Eva M. L{\'a}zaro and Ronald Sluys and Maria Pala and Giacinta Angela Stocchino and Jaume Bagu{\~n}{\`a} and Marta Riutort} } @article {302, title = {Evidence for the persistence of the land planarian species Microplana terrestris (M{\"u}ller, 1774) (Platyhelminthes, Tricladida) in microrefugia during the Last Glacial Maximum in the northern section of the Iberian Peninsula}, journal = {Molecular Phylogenetics and Evolution}, volume = {64}, number = {3}, year = {2012}, pages = {491-499}, author = {Marta {\'A}lvarez-Presas and Mateos, E. and Vila-Farre, M. and Sluys, R. and M Riutort} } @article {312, title = {Fluvial basin history in the northeastern Mediterranean region underlies dispersal and speciation patterns in the genus Dugesia (Platyhelminthes, Tricladida, Dugesiidae)}, journal = {Molecular Phylogenetics and Evolution}, volume = {66}, year = {2013}, month = {2013/3//}, pages = {877 - 888}, abstract = {

In this study we analyzed the phylogenetic relationships of eastern Mediterranean freshwater planarians of the genus Dugesia, estimated divergence times for the various clades, and correlated their phylogeographic patterns with geological and paleoclimatic events, in order to discover which evolutionary processes have shaped the present-day distribution of these animals. Specimens were collected from freshwater courses and lakes in continental and insular Greece. Genetic divergences and phylogenetic relationships were inferred by using the mitochondrial gene subunit I of cytochrome oxidase (COI) and the nuclear ribosomal internal transcribed spacer-1 (ITS-1) from 74 newly collected individuals from Greece. Divergence time estimates were obtained under a Bayesian framework, using the COI sequences. Two alternative geological dates for the isolation of Crete from the mainland were tested as calibration points. A clear phylogeographic pattern was present for Dugesia lineages in the Eastern Mediterranean. Morphological data, combined with information on genetic divergences, revealed that eight out of the nine known species were represented in the samples, while additional new, and still undescribed species were detected. Divergence time analyses suggested that Dugesia species became isolated in Crete after the first geological isolation of the island, and that their present distribution in the Eastern Mediterranean has been shaped mainly by vicariant events but also by dispersal. During the Messinian salinity crisis these freshwater planarians apparently were not able to cross the sea barrier between Crete and the mainland, while they probably did disperse between islands in the Aegean Sea. Their dependence on freshwater to survive suggests the presence of contiguous freshwater bodies in those regions. Our results also suggest a major extinction of freshwater planarians on the Peloponnese at the end of the Pliocene, while about 2 Mya ago, when the current Mediterranean climate was established, these Peloponnese populations probably began to disperse again. At the end of the Pliocene or during the Pleistocene, mainland populations of Dugesia colonized the western coast, including the Ionian Islands, which were then part of the continent.

}, keywords = {Aegean, Biogeography, COI, Divergence times, Freshwater planarians, ITS-1, Molecular clock, Phylogeography}, isbn = {1055-7903}, doi = {10.1016/j.ympev.2012.11.010}, url = {http://www.sciencedirect.com/science/article/pii/S1055790312004423}, author = {Eduard Sol{\`a} and Ronald Sluys and Gritzalis, Konstantinos and Marta Riutort} }