The Echinoid Directory

Elliptechinus Schneider, Sprinkle & Ryder, 2005, p. 753

Diagnostic Features
  • Test oval, composed of thin imbricate plates. In life  taller than wide (holotype 68 mm tall, 45 mm wide).
  • Apical disc small but plating unknown.
  • Ambulacra straight and narrow; biserial, but with alternate plates more or less excluded from the adradial border and with pore-pairs offset forming two discrete columns. Plating simple with rounded pore-pair on each plate.
  • Ambulacral tubercles small and perradial in postition.
  • Internally ambulacral plates form a shallow perradial groove but there are no overartching flanges. The adradial edge of ambulacral plates is not strongly unflooring adjacent interambulacral plates.
  • Interambulacral zones wide; composed of up to seven vertically and horizontally aligned columns of rhomboidal plates. Plates thin and subhexagonal in outline, strongly imbricating adradially.
  • All interambulacral plates bear a small imperforate and non-crenulate primary tubercle aborally and usually two smaller secondary tubercles adorally; the remainder of the plate is devoid of granulation.
  • Peristome small, detailed structure unknown.
  • Lantern present; small.
  • Spines uniform, short and straight, without cortex; forming a dense uniform felt.
Distribution Upper Carboniferous (Kasimovian) of Texas, USA.
Name gender masculine
Type Elliptechinus kiwiaster Schneider, Sprinkle & Ryder, 2005, p. 757, by original designation. Holotype, Texas Memorial Museum 1967TX23a.
Species Included
  • Only the type species.
Classification and/or Status Stem group Echinoidea; Lepidocentridae.

Monotypic; possibly only a subgenus of Pholidechinus.
Remarks This taxon was recently described and figured in excellent detail by Schneider et al. (2005).  They recognized that it was closest to Pholidechinus but distinguished it on the basis of its slightly more unequal-sized tubercles on interambulacral plates and its more extreme offsetting of pore-pairs and adradial pinching of every second plate.  However, these differences are slight and separation from Pholidechinus is hard to justify.

Schneider, C. L., Sprinkle, J. & Ryder, D. 2005. Pennsylvanian (Late Carboniferous) echinoids from the Winchell Formation, North-Central Texas, USA. Journal of Paleontology 79(4), 745-762.