What is Syndermata?

Syndermata is the phylogenetic clade containing the phyla Rotifera and Acanthocephala. It is nested within the clade Lophotrochozoa, a clade of Bilatarians according to the new synthesis of animal phylogeny (Halanych, 2004). The phylogenetic structure of each phyla are as follows:

Phylum Rotifera
Class Monogonta; Order Ploima, Flosculariacea, Collothecacea
Class Bdelloidea; Order Habrotrochidae, Philodinavidae, Philodinidae, Adinetidae
Class Seisonidea
Phylum Acanthocephala
Class Archiacanthocephala; Order Apororhynchida Gigantorhynchida, Moniliformida, Oligacanthorhynchida
Class Palaeacanthocephala; Order Echinorhynchida, Polymorphida
Class Eoacanthocephala; Order Gyracanthocephala, Neoechinorhynchida
Class Polyacanthocephala