The Echinoid Directory

Temnocidaris (Hirudocidaris) Smith & Wright, 1989, p. 78.

[= Hirudocidaris Smith & Wright, 1989, p. 78]

Diagnostic Features
  • Apical disc opening similar in diameter to peristome; plating unknown.
  • Ambulacra weakly sinuous; pore-pairs not conjugate with the interporal ridge not much larger than a pore. Perradial zone with horizontal row of subequal tubercles.
  • Interambulacral zones with single adapical plate with rudimentary tubercle. Primary tubercles perforate and non-crenulate (adapical tubercles with traces of crenulation on their adapical side). Areoles sunken.
  • Scrobicular tubercles fully developed; areoles circular and separated throughout. Extrascrobicular zones moderately well developed and densely covered in uniform secondary tubercles.
  • Small pits on horizontal plate sutures in interambulacral zones.
  • Primary spines shorter than test diameter; fusiform; ornamented with rather sharp, weakly beaded ribs; ending in small cap.
Distribution Cretaceous (Upper Albian to Campanian); Europe.
Name gender feminine
Type Cidaris hirudo Sorignet, 1850, p. 17, by original designation.
Species Included
  • H. uniformis (Sorignet, 1850): Upper Albian to Cenomanian, western Europe.
  • H. hirudo (Sorignet, 1850); Turonian to Campanian, Europe.
  • H. silesiaca (Schlueter, 1892); Turonian to Coniacian, Europe.
Classification and/or Status Cidaroida; Cidaridae; Stereocidarinae.

Monophyletic; a subgenus of Temnocidaris.
Remarks Close to Temnocidaris (Stereocidaris) but distinguished by the form of its spines: those of Hirudocidaris are short and ornamented with rather well-developed narrow ribs, while those of Stereocidaris are elongate and swollen near the base, with rather well-developed rows of thorns.

Smith, A. B. & Wright, C. W. 1989. British Cretaceous echinoids. Part 1, General introduction and Cidaroida. Monograph of the Palaeontographical Society [publication no. 578, issued as part of volume 141].