The Echinoid Directory

Triplacidia Bittner, 1891, p. 143

[Acrocircus Lambert, 1911, p. 7, type species Micropsis biarritzensis Cotteau, 1863]

Diagnostic Features
  • Profile low domal; oral surface tumid; ambitus below mid-height.
  • Apical disc small; plating loosely connected to corona and almost always missing; monocyclic where preserved.
  • Ambulacral plating trigeminate in echinid style. Pore-pairs arranged more or less uniserially to peristome, though slightly offset in triads at the ambitus and adapically in large specimens. Two subequal primary tubercles to each compound plate; perradial zone with small granules only and slightly depressed.
  • Interambulacral plates wide and low with row of small subequal tubercles; interradial zone of fine horizontally aligned rows of granules from ambitus to apex.
  • Primary tubercles imperforate and weakly crenulate.
  • No sutural pits or test sculpturing.
  • Peristomial relatively small and a little sunken, with sharp and relatively deep buccal notches.
  • Lantern and spines unknown.
Distribution
Eocene, southern Europe, North Africa, Arabian Peninsula, India.
Name gender feminine
Type
Micropsis veronensis Bittner, 1883, p. 444, by original designation.
Classification and/or Status
Euechinoidea; Camarodonta; unnamed family (triplacidiids).
Remarks

Bittmer 1891. Verh. geol. Reichsanst. Wien, 1891, p. 143

 Mortensen, T. (1943) A monograph of the Echinoidea Part III.2, Camarodonta 1. C. A. Reitzel, Copenhagen.