The Ecdysozoa are a large group of protostomian animals, erected by Aguinaldo et al. in 1997 primarily based on 18s rRNA data. They are sometimes ranked as a superphylum. The name comes from the Greek words ecdysis (molting) and zoon (animal) after a character common to the group.
Phyla considered Ecdysozoa are:
Besides the rRNA (and other nucleinic acid) sequencing data, some morphologic characters are common to the Ecdysozoa:
- inner insemination in many species
- lack of locomotory cilia
- females and males present (though some groups are parthenogenetic and may have lost males during evolution)
The Ecdysozoa concept is contradictory to the more traditional Articulata concept, where the Panarthropoda are combined to one taxon with the annelids. The annelids do not belong to Ecdysozoa but instead to the Trochozoa.
- Aguinaldo, A. M. A., J. M. Turbeville, L. S. Linford, M. C. Rivera, J. R. Garey, R. A. Raff, & J. A. Lake, 1997. Evidence for a clade of nematodes, arthropods and other moulting animals. Nature 387: 489-493.