• Teresa Adell
  • José M. Martín-Durán
  • Emili Saló
  • Francesc Cebrià


The phylum Platyhelminthes comprises dorso-ventrally flattened worms commonly known as flatworms (from the Greek platys, meaning flat, and helminthos, meaning worm) (for a general overview of this phylum, see Hyman 1951; Rieger et al. 1991). Platyhelminthes are one of the largest animal phyla after arthropods, mollusks, and chordates and includes more than 20,000 species, more than half of which are parasitic flatworms. Free-living flatworms (classically referred to as ‘Turbellaria’) live in a large variety of habitats, from freshwater springs, rivers, lakes, and ponds to the ocean and moist terrestrial habitats. Their size ranges from microscopic worms to the 30 m long tapeworms found in the sperm whale. Free-living flatworms are most often white, brown, grey, or black; polyclads (marine flatworms) and terrestrial species usually display bright colours and patterns. Molecular phylogenetic studies place the Platyhelminthes within the Spiralia (=Lophotrochozoa) clade. The most recent internal phylogenies support the subdivision of the Platyhelminthes into two main groups: the earliest branching lineages grouped into the paraphyletic ‘Archoophora’ and the more divergent monophyletic Neoophora (Laumer and Giribet 2014; Riutort et al. 2012). The ‘Archoophora’ includes those groups with endolecithal eggs. They are exclusively free-living organisms and are classified into three orders: Catenulida, Polycladida, and Macrostomida (Fig. 3.1). The Neoophora includes all groups with ectolecithal eggs. It comprises several free-living orders, together with the parasitic groups (the classes Trematoda, Cestoda, and Monogenea) united under the monophyletic Neodermata.


Hull Cell Parasitic Flatworm Yolk Cell Spiral Cleavage Indirect Development 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



We thank Bernhard Egger for providing platyhelminth images showed in Fig. 3.1, the schemes of platyhelminth embryogenesis in Fig. 3.2, and the images of larvae in Fig. 3.3. We thank Iain Patten for advice on the English. This work was supported by grant BFU2012-31701 (Ministerio de Economía y Competitividad, Spain) to F.C; grant BFU2008-01544 (Ministerio de Economía y Competitividad, Spain) to ES and TA; grant 2009SGR1018 (Agència de Gestió d’Ajuts Universitaris i de Recerca) to ES, FC, and TA; and grant AIB2010DE-00402 (Ministerio de Economia y Competitividad Accion Integrada). J.M.M-D. is supported by Marie Curie intra-European fellowship 329024.


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Copyright information

© Springer-Verlag Wien 2015

Authors and Affiliations

  • Teresa Adell
    • 1
  • José M. Martín-Durán
    • 2
  • Emili Saló
    • 1
  • Francesc Cebrià
    • 1
  1. 1.Department of Genetics, Faculty of BiologyInstitute of Biomedicine, University of BarcelonaCatalunya, BarcelonaSpain
  2. 2.Sars International Centre for Marine Molecular BiologyUniversity of BergenBergenNorway

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