Cephalorhyncha, Priapozoa Scalidophora is a group of marine pseudocoelomate ecdysozoans that was proposed on morphological grounds to unite three phyla: the Kinorhyncha, the Priapulida and the Loricifera.

[4] The introvert and abdomen are separated by a distinct neck region in all groups, but in adult macroscopic priapulids it becomes rudimentary in Priapulus and is completely absent in Halicryptus.

[5] However, the monophyly of the Scalidophora was not supported by two molecular studies, where the position of the Loricifera was uncertain[2] or as sister to the Panarthropoda.

[3] Both studies supported a reduced Scalidophora comprising the Kinorhyncha and Priapulida as sister phyla.

The two species in the genus Markuelia, known from fossilized embryos from the middle Cambrian, are thought to be stem scalidophorans.