@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 {162, title = {Schmidtea mediterranea phylogeography: an old species surviving on a few Mediterranean islands?}, journal = {BMC Evolutionary Biology}, volume = {11}, number = {1}, year = {2011}, chapter = {274}, doi = {10.1186/1471-2148-11-274}, url = {http://www.biomedcentral.com/content/pdf/1471-2148-11-274.pdf}, author = {Eva M. L{\'a}zaro and Harrath, Abdul Halim and Stocchino, Giacinta and Maria Pala and Jaume Bagu{\~n}{\`a} and Marta Riutort} } @article {274, title = {Evolutionary history of the Tricladida and the Platyhelminthes: an up-to-date phylogenetic and systematic account}, journal = {International Journal of Developmental Biology}, volume = {56}, year = {2012}, pages = {5-17}, chapter = {5}, abstract = {

Within the free-living platyhelminths, the triclads, or planarians, are the best-known group, largely as a result of long-standing and intensive research on regeneration, pattern formation and Hox gene expression. However, the group\’s evolutionary history has been long debated, with controversies ranging from their phyletic structure and position within the Metazoa to the relationships among species within the Tricladida. Over the the last decade, with the advent of molecular phylogenies, some of these issues have begun to be resolved. Here, we present an up-to-date summary of the main phylogenetic changes and novelties with some comments on their evolutionary implications. The phylum has been split into two groups, and the position of the main group (the Rhabdithophora and the Catenulida), close to the Annelida and the Mollusca within the Lophotrochozoa, is now clear. Their internal relationships, although not totally resolved, have been clarified. Tricladida systematics has also experienced a revolution since the implementation of molecular data. The terrestrial planarians have been demonstrated to have emerged from one of the freshwater families, giving a different view of their evolution and greatly altering their classification. The use of molecular data is also facilitating the identification of Tricladida species by DNA barcoding, allowing better knowledge of their distribution and genetic diversity. Finally, molecular phylogenetic and phylogeographical analyses, taking advantage of recent data, are beginning to give a clear picture of the recent history of the Dugesia and Schmidtea species in the Mediterranean.

}, doi = {10.1387/ijdb.113441mr}, url = {http://www.ijdb.ehu.es/web/paper.php?doi=113441mr}, author = {Marta Riutort and Marta {\'A}lvarez-Presas and Eva M. L{\'a}zaro and Eduard Sol{\`a} and Jordi Paps} } @article {524, title = {Dugesia sicula (Platyhelminthes, Tricladida): the colonizing success of an asexual Planarian}, journal = {BMC Evolutionary Biology}, volume = {13}, year = {2013}, chapter = {268}, abstract = {

Background Dugesia sicula is the only species of its genus not presenting an endemic or restricted distribution within the Mediterranean area. It mostly comprises fissiparous populations (asexual reproduction by body division and regeneration), most likely sexually sterile, and characterized by an extremely low genetic diversity interpreted as the consequence of a recent anthropic expansion. However, its fissiparous reproduction can result in an apparent lack of diversity within the species, since genetic variation within individuals can be as large as between them because most individuals within a population are clones. We have estimated haplotype and nucleotide diversity of cytochrome oxidase I within and among individuals along the species distribution of a broad sample of D. sicula, including asexual and the two only sexual populations known today; and predicted its potential distribution based on climatic variables. Our aim was to determine the centre of colonisation origin, whether the populations are recent, and whether the species is expanding. Results The species presents 3 most frequent haplotypes, differing in a maximum of 11 base pairs. As expected from their fissiparous mode of reproduction, in half of all the analysed localities many individuals have multiple heteroplasmic haplotypes. The distribution of haplotypes is not geographically structured; however, the distribution of haplotypes and heteroplasmic populations shows higher diversity in the central Mediterranean region. The potential distribution predicted by climatic variables based modelling shows a preference for coastal areas and fits well with the observed data. Conclusions The distribution and frequency of the most frequent haplotypes and the presence of heteroplasmic individuals allow us to gain an understanding of the recent history of the species, together with previous knowledge on its phylogenetic relationships and age: The species most probably originated in Africa and dispersed through the central Mediterranean. After one or multiple populations became triploid and fissiparous, the species colonized the Mediterranean basin, likely both by its own means and helped by human activities. Its present distribution practically fulfils its potential distribution as modelled with climatic variables. Its prevalence in coastal regions with higher water temperatures predicts a likely future expansion to northern and more interior areas following the increase in temperatures due to climate change.

}, doi = {doi:10.1186/1471-2148-13-268}, url = {http://www.biomedcentral.com/content/pdf/1471-2148-13-268.pdf}, author = {Eva M. L{\'a}zaro and Marta Riutort} }