Platyhelminthes) Challenges Current Classification: Proposal of Taxonomic Actions FERNANDO CARBAYO,MARTA ALVAREZ-PRESAS,CLAUDIA T
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Zoologica Scripta Molecular phylogeny of Geoplaninae (Platyhelminthes) challenges current classification: proposal of taxonomic actions FERNANDO CARBAYO,MARTA ALVAREZ-PRESAS,CLAUDIA T. OLIVARES,FERNANDO P. L. MARQUES, EUDOXIA M. FROEHLICH &MARTA RIUTORT Submitted: 8 December 2012 Carbayo, F., Alvarez-Presas, M., Olivares, C.T., Marques, F.P.L., Froehlich, E.M. & Accepted: 17 April 2013 Riutort, M. (2013). Molecular phylogeny of Geoplaninae (Platyhelminthes) challenges cur- doi:10.1111/zsc.12019 rent classification: proposal of taxonomic actions. —Zoologica Scripta, 42, 508–528. Despite likely being the most diverse group within the Tricladida, the systematics of land pla- narians (Geoplanidae) has received minor attention. The most species-rich ingroup, the sub- family 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 evolu- tionary 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-1a) and a mito- chondrial 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. *Corresponding author: Fernando Carbayo, Laboratorio de Ecologia e Evolucß~ao, Escola de Artes, Ci^encias e Humanidades (EACH), Av. Arlindo Bettio, 1000, S~ao Paulo, SP 03828-000, Brazil. E-mail: [email protected] Fernando Carbayo, Laboratorio de Ecologia e Evolucß~ao, Escola de Artes, Ci^encias e Humanidades (EACH), Universidade de S~ao Paulo (USP), Av. Arlindo Bettio, 1000, S~ao Paulo, SP, 03828- 000, Brazil. E-mail: [email protected] Marta Alvarez-Presas, Departament de Genetica, Facultat de Biologia and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Avinguda Diagonal, Barcelona, 643 E-08028, Spain. E-mail: [email protected] Claudia T. Olivares, Fernando P. L. Marques, and Eudoxia M. Froehlich, Departamento de Zoologia, Instituto de Bioci^encias, Universidade de S~ao Paulo (USP), Rua do Mat~ao, Travessa 14 Cidade Universitaria, S~ao Paulo, SP, 05508-900, Brazil. E-mail: [email protected], [email protected], [email protected] Marta Riutort, Departament de Genetica, Facultat de Biologia and Institut de Recerca de la Biodiv- ersitat (IRBio), Universitat de Barcelona, Avinguda Diagonal, Barcelona, 643 E-08028, Spain. E-mail: [email protected] Introduction throughout the world, especially in tropical regions. These There are over 800 species of land planarians (Geoplani- often colourful invertebrates range mostly from a few dae) predominantly inhabiting moist terrestrial habitats millimetres to over 20 cm in length and prey on soil 508 ª 2013 The Norwegian Academy of Science and Letters, 42, 5, September 2013, pp 508–528 F. Carbayo et al. Systematics of Geoplaninae invertebrates, including other land planarians (Winsor et al. 1998). The diversity of these tricladid flatworms is cur- rently organized into four subfamilies, Geoplaninae Stimp- son (1857), Bipaliinae Graff (1896), Microplaninae Pantin (1953) and Rhynchodeminae Graff (1896) (Sluys et al. 2009; see Riutort et al. 2012 for a revision). While subfami- lies Microplaninae, Rhynchodeminae and Bipaliinae are distributed in both hemispheres, the original distribution of Geoplaninae is confined within the limits of Neotropical region. Land planarians probably comprise the most specious taxon within tricladid flatworms. However, the group Fig. 1 Scheme of the phylogenetic relationships of the main remains poorly known despite its long taxonomic history in groups of land planarians after Alvarez-Presas et al. (2008) using which renowned scientists such as Charles Darwin, Fritz Sluys et al. (2009) nomenclature. Muller€ and Libbie H. Hyman, among others, have contrib- uted to its description, circumscription of taxonomic units and earlier notions of interrelationships among taxa (Muller€ (1953) and Froehlich (1967), who postulated that members 1774; Darwin 1844; Hyman 1951). As with many other of Microplaninae were the first to diverge based on the groups of invertebrates, progress in understanding this ele- morphology of the copulatory organs. None of these ment of our biodiversity has been undermined by the hypotheses were generated by any rigorous objective ana- restricted number of systematists interested in the group lytical protocol, and since then, no phylogeny of land pla- (Carbayo & Froehlich 2008), the unavailability of type narians based on the morphological data has been material for reference and the lack of adequate morpho- proposed. logical features to delimit species (Ogren & Sluys 1998; Although some studies used morphological characters to Winsor 2006) leading to poor descriptions and lack of a infer sister-group relationships among major lineages of phylogenetic framework upon which to base the classifica- Tricladida (e.g. Ball 1977, 1981; Sopott-Ehlers 1985; Sluys tion (Carbayo & Leal-Zanchet 2003). Nonetheless, land 1989), those proved to be insufficient to provide fully planarians have recently become of interest for various resolved phylogenetic hypotheses for this group. Our pres- reasons. On the one hand, some tropical species have ent knowledge on the phylogenetic relationships within become invasive, even considered pests, in Great Britain this group therefore has profited from the incorporation of and the United States (Cannon et al. 1999; Ducey et al. molecular data into the systematic study of planarians 1999; Iwai et al. 2010). On the other hand, they have been (Riutort et al. 2012). According to Sluys et al. (2009), shown to be good models for low-scale phylogeographical molecular data have provided radical shifts in our views of studies (Sunnucks et al. 2006; Alvarez-Presas et al. 2011). the phylogenetic relationships between the major lineages The evolutionary relationships among land planarians of triclads. A major finding was that land planarians were remain virtually unstudied. Early hypotheses of sister-group not sister of freshwater and maricolan triclads but they relationships among major lineages of land planarians have shared a common ancestor with only some members of pa- relied on biogeographical narratives involving breakage of ludicolan planarians, that is, Dugesiidae (Carranza et al. continents and dispersal events or a priori assumptions of 1998a,b; Sluys et al. 2009). However, the number of phylo- morphological character evolution. von Graff (1899) postu- genetic molecular studies for major tricladid lineages lated that land planarians originated in the lost continent remains scarce and with low taxonomic representation, and of Gondwana and, as a consequence of the geological phylogenetic hypothesis for geoplaninid land planarians breakage of the continent, they split into two groups. based on the molecular data has never been published. According to him, a lineage diversified in Australia and Geoplaninae is comprised of land planarians that posses a New Zealand (members of Caenoplaninae, currently Cae- broad ciliated creeping sole covering most of the ventral noplanini), and the other colonized South America (i.e. surface; dorsal testes; subepithelial or cutaneous longitudi- Geoplaninae) (Froehlich 1967). More recently, Winsor nal musculature well developed, arranged in bundles; and et al. (1998) proposed that rhynchodemids (at that time longitudinal parenchymal muscle absent or not well devel- Rhynchodeminae + Microplaninae, and currently split into oped, not forming a ring zone (Ogren & Kawakatsu 1990). two not sister groups, Microplaninae and Rhynchodemini) However, as new taxonomic studies come to light, these are the earliest divergent land planarians based on their characters are considered less robust because they have worldwide distribution. This view contradicts Marcus been revealed to be non-exclusive. For instance, species of ª 2013 The Norwegian Academy of Science and Letters, 42, 5, September 2013, pp 508–528 509 Systematics of Geoplaninae F. Carbayo et al. the geoplaninid taxon Anzoplanini Winsor 2006; possesses Here, we attempt to provide phylogenetic refinement for dorsal and ventral testes, and some geoplaninids have well- the Geoplaninae, based on the molecular data and using rig- developed parenchymal muscle fibres. In the only molecu- orous phylogenetic inference methods, which we consider lar phylogenetic study in which Geoplaninae have been desirable to reach a meaningful (i.e. phylogenetic) classifica- represented, the subfamily was classified as the sister group tion for these groups and to understand their evolution. of a clade comprised of members of Rhynchodeminae (cur- rently