The Echinoid Directory

• Test relatively small with raised ambulacra on aboral surface.
• Coronal plating weakly imbricate.
• Apical disc unknown.
• Ambulacral plating trigeminate with pore-pairs biserial at ambitus; plate compounding diadematid (demiplates at ambitus above and below major element).
• Two or three subequal tubercles on ambulacral plates.
• Interambulacral plates very wide and low. Multiple subequal tubercles on each plate, in two irregular rows adradially. Tubercles perforate and non-crenulate or effectively non-crenulate.
• Buccal notches extremely large and deep, associated with adradial tags.
• Peristome small.
• Spines slender, non-verticillate and hollow.

Early Eocene (Ypresian), Somalia.

Pedinopsis melo Kier, 1957, by original designation. Holotype (now lost) Sedgwick Museum, Cambridge C3007.

• Only the type species.

Acroechinoidea, Micropygoida, Micropygidae.

Monotypic.

The holotype and only known specimen of this interesting taxon has been lost. Luckily Philip (1963) provided a detailed description of the taxon. It is very similar to Micropyga in pore-pair arrangment and spine structure, but is readily distinguished by its smaller and denser tuberculation. Kierechinus has two or three subequal ambulacral tubercles and a double adradial row of interambulacral tubercles to each plate whereas Micropyga has just a single primary tubercle and a single row of large, rather spaced interambulacral tubercles.

Philip, G. 1963. A new genus of regular echinoid from the Lower Eocene of British Somaliland. Journal of Paleontology 37, 1104-1109.