The Echinoid Directory

• Test low domal
• Apical disc small, dicyclic. Periproct ovate; ocular plates projecting
• Ambulacral plating trigeminate; plate compounding in echinid style. Pore-pairs arranged in single series throughout. One primary tubercle to each compound plate, adradial in position. Perradial zone relatively wide and with secondary tubvercles and granules.
• Interambulacral plates with small central primary tubercle. remainder of plate eith scattered secondaries and miliaries. Often a radiating sculpture surrounds the primary tubercle.
• Primary tubercles imperforate and strongly crenulate.
• Peristomial small with small but distinct buccal notches.
• Auricles of perignathic girdle slender; generally touch perrradially but not fused.
• Spines unknown.

Miocene, South Australia.

Psammechinus (?) humilior Bittner, 1892, p. 337, by original designation.

• Only the type species.

Euechinoidea; Camarodonta; Temnopleuroida; Trigonocidaridae

Monotypic.

Distinguished from Ortholophus by its more strongly crenulate tubercles, unfused auricles and sharper buccal notches. Very like Asterechinus but distinguished by its ornamentation of anastomosing ridges.

Philip, G. M. 1969. The Tertiary echinoids of South-Eastern Australia IV. Camarodonta (2). Royal Society of Victoria Proceedings 82, 233-275, pls 3-16.