The Echinoid Directory

• Apical disc opening moderately large; plating unknown.
• Ambulacra almost straight, narrow; not expanded adorally. Plates compound into triads but details of plating unknown.
• Pore-pairs non-conjugate and arranged in weak arcs; a single primary tubercle to each plate.
• Interambulacral plates with single large primary tubercle and a distinct but much smaller interradial secondary tubercle. Remainder of plate covered in rather heterogeneous tuberculation.
• Interambulacral tubercles imperforate and non-crenulate throughout. Areoles of primary tubercles separated by granules above ambitus.
• Spines, lantern and perignathic girdle unknown.

Miocene, Patagonia.

Stereopedina ameghinoi de Loriol, 1903, by original designation.

Only the type species.

Acroechinoidea, Pedinoida, Pedinidae.

Monotypic; a subjective synonym of Caenopedina Agassiz, 1869

Unfortunately rather poorly known, having never been studied since de Loriol\'s original designation. The original illustrations lack detail, but the weakly arcuate columns of pore-pairs, large ambulacral and interambulacral primary tubercles suggest close similarity to Caenopedina.

Loriol, P. de 1903 (January). Notes pour servir à l’étude des échinodermes, Serie 2, 1. p. 11. Georg, Basle & Genève.