Despite likely being the most diverse group within the Tricladida, the systematics of land planarians (Geoplanidae) has received minor attention. The most species‐rich ingroup, the subfamily Geoplaninae, is restricted to the Neotropics. The systematics of Geoplaninae remains uncertain. Unique features supporting the genera are scanty; moreover, parts of the known species have been poorly described, making comparative studies difficult. Likewise the evolutionary relationships among land planarians remain insufficiently understood. In the present study, a phylogenetic hypothesis for selected taxa of Geoplaninae based on the molecular data is presented and discussed in the light of morphological features. Our phylogenetic inference is based on the fragments of three nuclear regions (18S, 28S rDNA and EF‐1α) and a mitochondrial marker (cytochrome oxidase I) for which we considered three optimality criteria (parsimony, maximum likelihood and Bayesian inference). Although our data provide little support for most basal nodes, our phylogenetic trees show a number of well‐supported clades, unveiling morphologically homogeneous groups. According to these results, we propose to separate Geoplana into Barreirana (formerly considered a subgenus), Cratera gen. n., Imbira gen. n., Matuxia gen. n., Obama gen. n. and Paraba gen. n., emend the diagnoses of Barreirana, Geoplana, Notogynaphallia, Pasipha and Xerapoa and review the classification of the species within these genera. For Geoplana goetschi sensu Marcus, (1951), a new name is proposed.

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Mitochondrial genomes (mitogenomes) are useful and relatively accessible sources of molecular data to explore and understand the evolutionary history and relationships of eukaryotic organisms across diverse taxonomic levels. The availability of complete mitogenomes from Platyhelminthes is limited; of the 40 or so published most are from parasitic flatworms (Neodermata). Here, we present the mitogenomes of two free-living flatworms (Tricladida): the complete genome of the freshwater species Crenobia alpina (Planariidae) and a nearly complete genome of the land planarian Obama sp. (Geoplanidae). Moreover, we have reanotated the published mitogenome of the species Dugesia japonica (Dugesiidae). This contribution almost doubles the total number of mtDNAs published for Tricladida, a species-rich group including model organisms and economically important invasive species. We took the opportunity to conduct comparative mitogenomic analyses between available free-living and selected parasitic flatworms in order to gain insights into the putative effect of life cycle on nucleotide composition through mutation and natural selection. Unexpectedly, we did not find any molecular hallmark of a selective relaxation in mitogenomes of parasitic flatworms; on the contrary, three out of the four studied free-living triclad mitogenomes exhibit higher A+T content and selective relaxation levels. Additionally, we provide new and valuable molecular data to develop markers for future phylogenetic studies on planariids and geoplanids.

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 upto-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

Many tropical terrestrial planarians (Platyhelminthes, Geoplanidae) have been introduced around the globe. One of these species is known to cause significant decline in earthworm populations, resulting in a reduction of ecological functions that earthworms provide. Flatworms, additionally, are a potential risk to other species that have the same dietary needs. Hence, the planarian invasion might cause significant economic losses in agriculture and damage to the ecosystem. In the Iberian Peninsula only Bipalium kewense Moseley, 1878 had been cited till 2007. From that year on, four more species have been cited, and several reports of the presence of these animals in particular gardens have been received. In the present study we have: (1) analyzed the animals sent by non-specialists and also the presence of terrestrial planarians in plant nurseries and garden centers; (2) identified their species through morphological and phylogenetic molecular analyses, including representatives of their areas of origin; (3) revised their dietary sources and (4) used Species Distribution Modeling (SDM) for one species to evaluate the risk of its introduction to natural areas. The results have shown the presence of at least ten species of alien terrestrial planarians, from all its phylogenetic range. International plant trade is the source of these animals, and many garden centers are acting as reservoirs. Also, landscape restoration to reintroduce autochthonous plants has facilitated their introduction close to natural forests and agricultural fields. In conclusion, there is a need to take measures on plant trade and to have special care in the treatment of restored habitats.