The Echinoid Directory

Family Triadotiaridae Hagdorn, 1995, p. 249

[=Triadotiaroida Hagdorn, 1995, p. 249]


 Stem group cidaroids with:

  • test large, plating imbricate
  • ambulacral plating pseudocompound; pore-pairs in oblique arcs of 3, each associated with a primary tubercle
  • interambulacral plates wide with single large primary tubercle; primary tubercle perforate and crenulate, and with sunken areole. Areoles confluent at ambitus and adorally; scrobicular tubercles weakly differentiated
  • perignathic girdle well developed; composed of large apophyses
  • lantern with grooved teeth
  • primary spines stout, cylindrical, without cortex.
Middle Triassic, Europe

This cidaroid resembles Lenticidaris in its interambulacral structure and tuberculation, but is immediately distinguished from this, and indeed from most other cidaroids, by its unique pseudocompound ambulacra and broad pore zones. Only Heterocidaris and Serpianotiaris have comparable ambulacra, and they both have different tuberculation and perignathic girdle. The taxon was described in admirable detail by Hagdorn (1995).

Hagdorn, H. 1995. Die Seeigel des germainischen oberen Muschelkalks. Geologisches und Palaontologisches Mittelilungen, Innsbruck. 20, 245-281.