Orthonectida
/ˌɔːθə(ʊ)ˈnɛktɪdə
/plural noun Zoology
A minor phylum of mesozoan worms which are internal parasites of a range of marine invertebrates.They are now believed to be made up of two, possibly unrelated, groups: the Dicyemida and Orthonectida....
- As it turns out, the Orthonectida are almost certainly metazoans, particularly under our stem group definition; but it's anyone's guess whether they, or any other members of the mysterious Mesozoa, are also bilaterians.
Derivatives
orthonectid
- In some orthonectids, circular and longitudinal muscles occur beneath the epidermis.
Origin
Modern Latin (plural), from Greek orthos 'straight' + nektos 'swimming' (see nekton).