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Figure 1 | EvoDevo

Figure 1

From: Developmental diversity in free-living flatworms

Figure 1

Diversity of body plans and phylogeny of free-living platyhelminthes. Left side, consensus tree of various published phylogenetic reconstructions. The Catenulida is the sister group of the Rhabditophora [15–18], the Macrostomorpha the sister group to all other Rhabditophora [2, 15, 19]. The Polycladida is the sister group to the Neoophora [2], and the Lecithoepitheliata is sister group to all other Neoophora [2, 20]. Subsequently, the Proseriata is the sister group of all other Neoophora except the Lecithoepitheliata [16, 20, 21], while the Neodermata is sister group to Rhabdocoela and Adiaphanida (Fecampiida, Prolecithophora, Tricladida) [15, 16, 20, 21]. The Rhabdocoela is sister group to Adiaphanida [15–17, 20, 21]. Within the Adiaphanida, Fecampiida is sister group to Prolecithophora plus Tricladida [15–17, 20, 21]. According to Willems and coworkers, the Bothrioplanida is sister group to Adiaphanida plus Neodermata, although their overall tree topology is different than depicted here, where Bothrioplanida is sister group to the Eulecithophora [22]. 1 entolecithal eggs, 2 quartet spiral cleavage, 3 hull cells made from macromeres, 4 larvae, 5 ectolecithal eggs, 6 hull cells made from micromeres, 7 loss of spiral cleavage, 8 disperse cleavage (Blastomerenanarchie), 9 hull cells made of yolk cells (at least in some representatives), 10 embryonic pharynx and "yolk larvae". Right side, live images of adult representatives of the major taxa of free-living flatworms with their developing embryos. Stenostomum sthenum with two developing zooids, fresh water, about 1 mm long. Mid-stage embryo, about 150 μm in diameter. Macrostomum lignano, marine, about 1 mm long. 4-cell stage, about 150 μm in diameter. Prosthiostomum siphunculus, marine, about 1 cm long. Several embryos per cocoon, several cocoons per egg plate. Embryos about 130 μm in diameter. Geocentrophora sphyrocephala, fresh water, about 1 mm long. No embryonic stage provided. Monocelis fusca, marine, about 1.2 mm long. Egg capsule of an unidentified proseriate, about 150 μm in diameter. Rhynchomesostoma rostratum, fresh water, about 1.3 mm long. Egg capsule with late embryo (note eyes) of a summer egg, about 170 μm in diameter. Procerodes littoralis, marine, about 4 mm long. 2 cocoons, the one to the right opened. Cocoon about 1 mm in diameter. Lower left corner hatched juvenile. Anterior of adult specimens to the left.

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