Clade of worm-like animals
Nematoida is a clade of pseudocoelomate free living or parasitic animals . It consists of phyla Nematoda and Nematomorpha .[ 2] [ 3] [ 4] The two groups share a number of features in common; the presence of a cloaca in both sexes, aflagellate sperm, and a cuticle made of collagen .[ 5]
Its position within Ecdysozoa is uncontroversial, but the identity of their closest relatives has been debated. Under the Cycloneuralia hypothesis, the nematoids are considered to be closest to Scalidophora , named for the ring-shaped brains found in these animals.[ 6] However, this group has seen less support in phylogenetic analyses, with the Cryptovermes hypothesis being more consistently supported,[ 5] [ 7] [ 8] which groups the nematoids with the panarthropods , although the issue is still not completely settled.
^ Poinar, George (January 2008). "Palaeonema phyticum gen. n., sp. n. (Nematoda: Palaeonematidae fam. n.), a Devonian nematode associated with early land plants" . Nematology . 10 (1): 9–14. doi :10.1163/156854108783360159 .
^ "articulata" . Archived from the original on 2010-05-10. Retrieved 2009-06-28 .
^ Telford MJ, Bourlat SJ, Economou A, Papillon D, Rota-Stabelli O (April 2008). "The evolution of the Ecdysozoa" . Philos. Trans. R. Soc. Lond. B Biol. Sci . 363 (1496): 1529–37. doi :10.1098/rstb.2007.2243 . PMC 2614232 . PMID 18192181 .
^ Telford MJ, Bourlat SJ, Economou A, Papillon D, Rota-Stabelli O (April 2008). "The evolution of the Ecdysozoa" . Philos. Trans. R. Soc. Lond. B Biol. Sci . 363 (1496): 1529–37. doi :10.1098/rstb.2007.2243 . PMC 2614232 . PMID 18192181 .
^ a b Telford, Maximillian; et al. (11 January 2008). "The evolution of the Ecdysozoa" . Philosophical Transactions . 363 (1496): 1529–1537. doi :10.1098/rstb.2007.2243 . PMC 2614232 . PMID 18192181 .
^ Hejnol, Andreas (2015). "Cycloneuralia". Evolutionary Developmental Biology of Invertebrates 3 . pp. 1–13. doi :10.1007/978-3-7091-1865-8_1 . ISBN 978-3-7091-1864-1 .
^ Howard, Richard. "The Deep Evolution of Ecdysozoa" . ProQuest .
^ Howard, Richard; et al. (10 March 2022). "The Ediacaran origin of Ecdysozoa: integrating fossil and phylogenomic data". Journal of the Geological Society . 179 (4). Bibcode :2022JGSoc.179..107H . doi :10.1144/jgs2021-107 . hdl :2445/186596 .