7-481: Neodermata is a clade of rhabditophoran flatworms containing the parasitic groups Trematoda , Monogenea and Cestoda . All neodermatans are parasites , in many groups having a free-swimming larval stage. The most striking feature uniting all neodermatans is that the ciliated epidermis (typical of most flatworms) is cast off in adult worms, being replaced by a syncytium called tegument or neodermis . Other characters found in all neodermatans are related to
14-399: Is a subphylum (previously a class) of flatworms . It includes all parasitic flatworms (clade Neodermata ) and most free-living species that were previously grouped in the now obsolete class Turbellaria . Therefore, it contains the majority of the species in the phylum Platyhelminthes , excluding only the catenulids , to which they appear to be the sister group . The clade Rhabditophora
21-415: Is turned into a syncytium in adult forms. Another important synapomorphy of the group is the duo-glandular adhesive system. It is a structure of the epidermis containing three different cell types: anchor cells, adhesive glands and releasing glands. The adhesive glands secrete an adhesive substance that attaches the anchor cells to a surface, while the releasing glands secrete a substance able to release
28-465: The anatomy of the protonephridium and the rootlets of epidermal locomotory cilia . Currently, the monophyly of Neodermata is undisputed, being supported by both morphological and molecular data. It is clear that they evolved from free-living flatworms ( turbellarians ), but their sister-group was for a long time a matter of debate. The first attempts to reconstruct the phylogeny of flatworms, based on morphological evidence, considered Rhabdocoela to be
35-412: The anchor cells from surfaces. This systems allows rhabditophorans to adhere and release quickly from the substrate, even several times in a second. The secretory organs of rhabditophorans, the protonephridia , also have a unique anatomy in which the flame cells and tube cells present a series of cytoplasmic projections that overlap, forming a two-cell 'weir'. The following orders are recognised in
42-424: The sister-group of Neodermata, but this was based on weak morphological similarities and was not supported by molecular studies. The most recent evidences put the order Bothrioplanida as the sister-group of Neodermata, uniting them in a clade called Bothrioneodermata . Rhabditophora See text Rhabditophora (from rhabdito -, rhabdite + Greek -φορος [- phoros ], bearer, i.e., "rhabdite bearers")
49-441: Was originally erected by Ulrich Ehlers in 1985 based on morphological analyses and its monophyly was later confirmed by molecular studies. Rhabditophorans are characterized by the presence of lamellated rhabdites , rodlike granules secreted in the cells of the epidermis and consisted of concentric lamellae . They are absent in the clade Neodermata , most likely due to a secondary loss of this feature because their epidermis
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