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Aarchaeocidaris Webster, 1997, p. 37

Diagnostic Features	Semi-rigid test Four columns of interambulacral plates, two columns of ambulacral plates, ambulacral plates slightly overlap interambulacral plates Pore pairs uniserial Lacking large central boss on interambulacral plates (after Webster 1997)
Distribution	Lower Carboniferous (Mississippian - Tournaisian) of northern Utah, western Wyoming. Upper part of Lodgepole Formation, Strawberry Creek, Lincoln Co., Wyoming; Brush Creek Member, Henderson Canyon Formation, Beirdneau Hollow, Logan Canyon, Cache Co., Utah.
Name gender	feminine
Type	Aarchaeocidaris strawberryensis Webster, 1937, p. 37, by original designation. Holotype USNM 487247, paratypes USNM 487248, 487249
Species Included	Only the type species.
Classification and/or Status	Junior synonym of Palaechinus
Remarks	Additional diagnostic characters of the types are relatively thick, non-imbricate interambulacral plates with fine tuberculation; ambulacral plates all equal in size, slightly imbricate over interambulacral plates along adradial suture; pores biserial, located along adradial edge of plates; apical system small, monocyclic, 2-3 gonopores per gential plate. These characters are diagnostic for Palaechinidae, and suggest a closer affinity with Palaechinus than Maccoya. Webster, Gary D. 1997. Lower Carboniferous Echinoderms from Northern Utah and Western Wyoming. Bulletin of the Utah Geological Survey 128, 1-65.