Fig. 1.

(A) Phylogenetic analysis of 23 animal species using partial sequences of 43 genes. Figure modified from Egger et al. (80). (B) Interference contrast image and a diagrammatic representation of an adult M. lignano. (C) Phylogenomic analysis of 27 flatworm species (21 free-living and 6 neodermatan) using >100,000 aligned amino acids. Figure modified from Egger et al. (2). (D) Electron micrograph of a M. lignano neoblast. Note the small rim of cytoplasm (yellow) and the lack of cytoplasmic differentiation. Er, endoplasmic reticulum; mi, mitochondria; mu, muscle; ncl, nucleolus; nu, nucleus (red). (E) Immunofluorescence labeling of dividing neoblasts with EdU (red) in an adult worm. All cell nuclei are stained with DAPI (blue). DE, developing eggs; O – ovaries; T, testes. Asterisks denote eyes.