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.
^Howard, Richard; et al. (10 March 2022). "The Ediacaran origin of Ecdysozoa: integrating fossil and phylogenomic data". Journal of the Geological Society.
doi:
10.1144/jgs2021-107.
hdl:2445/186596.