Neodermata is a clade of containing the parasitic groups Trematoda, Monogenea and Cestoda.
Description
All neodermatans are
, in many groups having a free-swimming
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 the anatomy of the
protonephridium and the rootlets of epidermal locomotory
cilia.
Phylogeny
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 (
), 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 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.
