The Echinoid Directory

Triadocidaris Doderlein, 1887, p. 39

Diagnostic Features
  • Test up to 25 mm in diameter, depressed; plating imbricate.
  • Apical disc about 50% test diameter; plates not bound to the corona; dicyclic with large genital plates and circular periproct.
  • Ambulacra narrow and slightly sinuate; composed of simple plates throughout with every second or third plate at the ambitus slightly enlarged.
  • Pore-pairs small and non-conjugate. Primary tubercle on each plate.
  • Interambulacral zones wide with about 5 pentagonal plates in a column.
  • Single large primary interambulacral tubercle with massive mamelon; mamelons increase in size adapically and are imperforate and non-crenulate, except adapically where mamelons have a rudimentary perforation.
  • Well developed scrobicular circle surrounds primary tubercles; extrascrobicular zone more or less absent.
  • Peristome large; no buccal notches.
  • No lantern supports developed.
Distribution
Late Triassic (Carnian); Europe.
Name gender feminine
Type
Cidaris subsimilis Munster, in Wissmann & Munster, 1841, p. 40, by original designation. Lectotypes: Bayerische Staatsammlung fur Palaeontologie und Historische Geologie, Munchen, Germany AS VII 437.
Species Included
  • T. subsimilis (Munster, 1841); Carnian, Italy.
  • T. suessi (Laube, 1865); Carnian, Italy.
  • T. venusta (Munster, 1841); Carnian, Italy.
  • T. giauensis (Zardini, 1973); Carnian, Italy.
  • T. persimilis Bather, 1909; Carnian, Hungary.
Classification and/or Status

?Euechinoidea stem group, Triadocidaridae.

?

Remarks

Differs from Levicidaris in having almost no interradial tuberculate zone but is otherwise very similar.

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