The Spiralia are a morphologically diverse clade of protostome animals, including within their number the molluscs, annelids, platyhelminths and other...

deuterostome embryos differ in several other ways. Many protostomes (the Spiralia clade) undergo spiral cleavage during cell division instead of radial cleavage...

a pseudocoelom. The Spiralia are a large group of protostomes that develop by spiral cleavage in the early embryo. The Spiralia's phylogeny has been disputed...

(/ləˌfɒtroʊkoʊˈzoʊə/, "crest/wheel animals") is a clade of protostome animals within the Spiralia. The taxon was established as a monophyletic group based on molecular evidence...

more superphyla among the protostomes, Ecdysozoa (molting animals) and Spiralia. The arrow worms (Chaetognatha) have proven difficult to classify; recent...

priapulids), grouped together as Ecdysozoa. While annelids are placed among the Spiralia (making them more closely related to mollusks, flatworms and such), having...

Animals are multicellular eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen...

developmental features are at odds with deuterostomes and are either akin to Spiralia or unique to Chaetognatha. Molecular phylogeny shows that Chaetognatha...

gnathiferans are direct developers. Though gnathiferans are included in Spiralia, rotifers and chaetognaths do not exhibit spiral cleavage. Little is known...

scientists have criticized this argument; saying it’s based on paraphyletic Spiralia, assignments of sexual modes for the phylum level than the species level...