Molecular phylogeny of land and freshwater planarians (Tricladida, Platyhelminthes): from freshwater to land and back

Publication Type:Journal Article
Year of Publication:2008
Authors:M. Álvarez-Presas, Baguñà, J., Riutort, M.
Journal:Molecular Phylogenetics and Evolution
Volume:47
Start Page:555
Pagination:555-568
Date Published:05/2008
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.

URL:http://www.sciencedirect.com/science/article/pii/S1055790308000390
DOI:10.1016/j.ympev.2008.01.032
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith