The Echinoid Directory

• Small, discoidal test with flat base, margin moderately sharp.
• Apical disc slightly anterior; 4 gonopores.
• Petals well developed; anterior petal widely open distally, others slightly closing distally.
• Peristome central.
• Basicoronal circlet with interambulacral plates only slightly projecting.
• Interambulacra all discontinuous adorally, separated by first post-basicoronal ambulacral plates; anterior interambulacra only just separated.
• Periproct opening marginal to just supramarginal opening in third post-basicoronal pair of interamulacral plates.
• Food grooves simple, not forming well-marked grooves.
• Internal partitioning unknown.

Upper Miocene of California, USA.

Scutella gabbi var. tenuis Kew, 1920 [= Echinarachnius gabbii kleinpelli Grant & Hertlein 1938], by original designation.

• Only the type species.

Clypeasteroida, Scutellina, Scutelliformes, Echinarachniidae.

Monotypic; Subjective junior synonym of Scutellaster.

Durham (1955) gave the distinguishing features of this genus as three pairs of post-basicoronal plates on oral surface, and marginal ambulacral plates without reduced altitude. In oral plating the type is not much different from that found in Echinarachnius and there seems little justification in separating the two on such minor characters.

J. W. Durham 1955. Classification of clypeasteroid echinoids. University of California Publications in Geological Sciences 31(4), 73-198.