Molecular phylogeny of Geoplaninae (Platyhelminthes) challenges current classification: proposal of taxonomic actions

Abstract

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.

Planarian (Platyhelminthes, Tricladida) Diversity and Molecular Markers: A New View of an Old Group

“…Organisms with low dispersal ability and a high specialization, like terrestrial planarians, can therefore improve the resolution of these predictions. In a subsequent work [31], the patterns and levels of nucleotide diversity of the land planarian species Cephaloflexa bergi Riester, 1938 were analysed in 11 SAF conservation units (inside and outside the Serra do Mar corridor, a connection between preserved areas to facilitate gene flow). The results show a high level of nucleotide diversity, genetically structured populations and the molecular mark of an isolation-by-distance process.…”

Insights into the origin and distribution of biodiversity in the Brazilian Atlantic forest hot spot: a statistical phylogeographic study using a low-dispersal organism

“…We used Maximum Likelihood and Bayesian Inference methods to estimate phylogenetic relationships independently for COI and ITS-1 data sets. Outgroup species selection was based on a phylogenetic study of Geoplaninae (Carbayo et al, 2013).…”

Observations on food preference of Neotropical land planarians (Platyhelminthes), with emphasis on Obama anthropophila, and their phylogenetic diversification

“…Capture of woodlice by its close relative I. rezendei (see Carbayo et al 2013) is similar (MC Ramos, unpublished data). The cutaneous longitudinal-ventral muscle fibers of all the species of this clade are disposed to be fan-like, thereby giving rise to a cephalic retractor muscle.…”

“…However, knowledge has accumulated on the diets of species from Luteostriata, Cephaloflexa and Obama. Furthermore, a sound classification of most geoplaninid genera is also currently available (Carbayo et al 2013). Thus, hypotheses relating feeding behavior with phylogeny can now be formulated.…”