The Echinoid Directory

• Test known from cast of aboral surface only.
• Apical disc small, monocyclic; genital plates larger than oculars and projecting interradially; multiple gonopores on each genital plate arranged as an arc.
• Ambulacra narrow aborally, straight, multiserial, with 6 columns of small hexagonal plates, the innermost series being more elongate with perradial zone; medial zone of ambulacra convex.
• Pore-pairs forming wide adradial bands.
• Interambulacra of up to five columns of rather regular, hexagonal plates.
• A large primary tubercle on some adradial plates; with sunken areole. Other plates apparently with secondary granulation only. All plates rather tumid.
• Oral surface, spines and lantern all unknown.

Lower Carboniferous, Ireland.

Archaeocidaris harteiana Bailey, 1874, p. 42 by original designation.

• Only the type species.

Stem group Echinoidea; Proterocidaridae.

Monotypic.

The presence of large primary tubercles on some adradial plates suggests this does not belong to the Palaechinidae, despite the similarity between its ambulacral plating and that of Maccoya. The closest taxon appears to be Pholidocidaris, which also has occasional large primary tubercles on adradial interambulacral plates adapically, and has multiserial ambulacra adapically.

Jackson, R. T. 1912. Phylogeny of the Echini, with a revision of Palaeozoic species Memoirs of the Boston Society of Natural History 7, 491 pp. 76 pls.

Neumayr, M. 1881. Sitzber. Akad. Wiss. Wien. math. nat. Cl. 84, p. 174