Alternative spelling: Somasteroida
Full reference: W. K. Spencer. 1951. Early Palaeozoic starfish. Philosophical Transactions of the Royal Society of London, series B 235(B623):87-129
Parent taxon: Asterozoa according to D. B. Blake 2013
See also Blake 1989, Blake 2018, Blake and Guensburg 1993, Dean Shackleton 2005, Hunter and Ortega-Hernández 2021, Owen 1965, Sepkoski 2002, Spencer 1951 and Spencer and Wright 1966
Sister taxa: Asteroidea, Catervaparmasteridae, Eopentaroida, Falloasteridae, Ophiuroidea, Phragmactinidae, Stenuroidea, Auluroidea
Subtaxa: Archegonaster Archegonasteridae Catervaparmaster Chinianasteridae Goniactinida
Distribution:
• Fennian of France (1 collection)
• Arenig of France (1)
• Ordovician of the Czech Republic (1), France (2), Morocco (2), the United Kingdom (1)
• Tremadoc of Morocco (1)
• Ibexian of United States (1: Nevada)
Total: 10 collections including 13 occurrences