The Echinoid Directory

• Test small (8 mm diameter), depressed; plating rigid.
• Apical disc slightly less than half the test diameter; plates not bound to the corona; plating unknown.
• Ambulacra narrow and almost straight; composed of simple plates throughout. No bevelling of ambulacral plates under interambulacral plates.
• Pore-pairs small and non-conjugate. Perradial tuberculate zone very narrow (equal to pore-pair width); with a primary tubercle to each element.
• Interambulacral zones wide with about 5 pentagonal plates in a column.
• Single large primary interambulacral tubercle on each plate surrounded by scrobicular circle of enlarged tubercles. No extrascrobicular granulation.
• Primary interambulacral tubercles with crenulate and perforate mamelon; mamelons increase in size adapically.
• No buccal notches.
• No lantern supports around the inner edge of the peristome.

Late Triassic (Carnian); Italy.

Cidaris rinbianchi Zardini, 1973, p. 11, by original designation. Holotype: Museo di Cortina d'Ampezzo, Italy, 125-M-Z.

• Only the type species.

?Stem group Euechinoidea; Paurocidaridae.

Monotypic.

Differs from Triadocidaris and other triadocidarids in having crenulate tubercles and ambulacral zones that are not bevelled beneath the interambulacral zones. Differs from more advanced Cidaroidea in lacking a perignathic girdle of apophyses.

Kier, P.M. 1977. Triassic echinoids. Smithsonian Contributions to Paleobiology 30, 1-88.