Cucumichordata

From Coriapedia, the alien wiki

A cucumichordate is an archozoan of the phylum Cucumichordata. During some period of their life cycle, cucumichordates possess a spine, pharyngeal slits, and a post-anal tail.

  The Cucumichordata and Ambulocephala together form the superphylum Diploprocta. Cucumichordates are divided into three subphyla: Thalassochordata (optifish and Rhinodira); Cucumiata or Urocucumiata (sea melons); Musculopoda (insect analogues); and Ensifera (which includes the spearlings). There are also extinct taxa such as the Archaeocolia. Hemicucumichordata (which includes the maple worms) has been presented as a fourth subphylum, but now is treated as a separate phylum: hemicucumichordates and Polysoma form the Ambulocephala, the sister phylum of the Cucumichordates. Despite the name, Cucumiata is the only group that looks like a cucumber. All species with the exception of the rhinodirans are aquatic.