Ctenocystoidea

Ctenocystoidea Temporal range: Wuliuan–Sandbian PreꞒ Ꞓ O S D C P T J K Pg N
A specimen of Ctenocystis
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Superphylum:	Deuterostomia
Clade:	Ambulacraria
Phylum:	Echinodermata
Class:	†Ctenocystoidea Robison & Sprinkle, 1969
Type genus
Ctenocystis Robison & Sprinkle, 1969
Genera
†Conollia †Courtessolea †Ctenocystis †Etoctenocystis †Gilcidia †Jugoszovia †Pembrocystis

Ctenocystoidea is an extinct clade of echinoderms, which lived during the Cambrian and Ordovician periods. Unlike other echinoderms, ctenocystoids had bilateral symmetry, or were only very slightly asymmetrical. They are believed to be one of the earliest-diverging branches of echinoderms, with their bilateral symmetry a trait shared with other deuterostomes. Ctenocystoids were once classified in the taxon Homalozoa, also known as Carpoidea, alongside cinctans, solutes, and stylophorans.^[1] Homalozoa is now recognized as a polyphyletic group of echinoderms without radial symmetry. Ctenocystoids were geographically widespread during the Middle Cambrian, with one species surviving into the Late Ordovician.