The Echinoid Directory

• Test relatively small; known from fragments only.
• Apical disc unknown.
• Interambulacra composed of 6 plates per series. Interambulacral plates only slightly wider than tall at ambitus. Primary tubercle with relatively large mamelon which is perforate and with a narrow and occasionally faintly crenulate platform (crenulation developed around adapical side of mamelon adapically); mamelons increasing in size adapically. Areoles circular; strongly incised; only the most adoral two plates with confluent areoles.
• Scrobicular tubercles differentiated and completely surround areole on all but the most adoral plates. Extrascrobicular zone with fine, dense granulation; best developed interradially. Plates depressed towards interradial and adoral/adapical sutures but no pits or naked zone developed.
• Adradial suture of interambulacral plates more or less vertical and tesselate.
• Ambulacra narrow, weakly sinuous. Pore-pairs non-conjugate, the two pores separated by a narrow interporal partition. Perradial tuberculate zone slightly wider than a pore-pair, with a marginal primary tubercle and a smaller inner tubercle. Tubercles uniform throughout.
• Perignathic girdle of well developed apophyses.
• Spines unknown.

Upper Triassic (Norian), Peru.

Triassicidaris peruviensis Smith, 1994, p. 186, by original designation.

• Only the type species.

Cidaroida; Cidaridae, ?Cidarinae.

Monotypic.

The simple ambulacral plating with uniform tuberculation places this genus in the Cidaridae, and its perforate tubercles suggest its affinities lie with Cidarinae. However, a large time gap separates this taxon from other members of the subfamily and some doubt must therefore remain as to the correctness of this placement.

Smith, A. B. 1994. Triassic echinoids from Peru. Palaeontographica A, 233, 177-202, pls 1-6.