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The Echinoid Directory

Echinopsis Agassiz, 1840, p. 18

[=Hebertia Michelin, 1859, p. 147, type species Hebertia parisiensis Hebert, 1859; =Leiopleurus, Lambert, 1902, p. 37, type species Psammechinus orbignyi Cotteau, 1883; = Stenechinus Arnold & Clark, 1927, type species Stenechinus regularis Arnold & Clark, 1927; =Micropsidia Pomel, 1869, p. 41, type species Echinopsis leymeriei Cotteau, in Cotteau & Leymerie, 1859, p. 326]

Diagnostic Features
  • Test subglobular with rounded ambitus.
  • Apical disc small; plates firmly bound to corona. Plating hemicyclic with ocular plates I and V exsert in type species (dicyclic in others). Periproct large and subcircular with smooth rim.
  • Ambulacra more or less straight; plating trigeminate throughout with pore-pairs uniserial. Plate compounding style with all three elements reaching the perradius but with the lowest of the three distinctly larger.
  • Primary tubercle on each compound plate situated close to the pore zone. Perradial zone broad and covered in fine granules.
  • Interambulacral plates wide; with a small central primary tubercle the remainder of the plate with small granules arranged in two or three horizontal rows.
  • Primary tubercles perforate and crenulate.
  • No sutural pitting.
  • Peristome small, weakly depressed, with deep and sharp buccal notches.
  • Perignathic girdle, lantern and spines unknown.
Distribution
Late Palaeocene - Eocene, Europe, North Africa, Caribbean
Name gender feminine
Type
Echinus elegans Agassiz in Agassiz & Desor, 1846, p. 354, by original designation.
Species Included
  • E. elegans (Agassiz, in Agassiz & Desor, 1846); Eocene, western Europe
  • E. simplex (Hawkins, 1924); Eocene (Lutetian), Jamaica.
  • E. regularis (Arnold & Clark, 1927); Eocene, Jamaica
  • E. parisiensis (Michelin, 1859); Eocene, France
  • E. orbignyi (Cotteau, 1883); Eocene, Spain.
Classification and/or Status
Euechinoidea, Camarodonta, Temnopleuroida.
Remarks
The lack of ornamentation in the form of sutural pits or radiating ridges sets this genus appart from all others in the family. Probably sister group to the unsculpted temnopleurids.