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The Echinoid Directory

Tylocidaris Pomel, 1883, p. 109

[=Merocidaris Thiery, 1928, p. 180; type species Cidaris honorinae Cotteau, 1880

See also: Tylocidaris (Tylocidaris) Pomel, 1883; Tylocidaris (Oedematocidaris) Smith & Wright, 1989; Tylocidaris (Sardocidaris) Lambert, 1907; Tylocidaris (Psychocidaris) Ikeda, 1935]

Diagnostic Features
  • Apical disc larger in diameter than peristomial opening; plating dicyclic.
  • Ambulacra narrow, weakly sinuous. Pore-pairs narrow, non-conjugate, the two pores closely spaced in each pair.
  • Ambulacral tuberculation uniform throughout; all plates simple.
  • Perradial zone narrow with marginal tubercle and smaller inner tubercle to each plate.
  • Interambulacral zones composed of 5-8 plates. Primary tubercles offset towards adradial suture. Oral and ambital tubercles imperforate, adapical tubercles may have a rudimentary perforation; all tubercles non-crenulate. Areoles sunken, with complete scrobicular circles. Extrascrobicular granules uniform and dense.
  • Peristomial plating composed entirely of ambulacral elements; ambulacral plates biserially arranged in outer part.
  • Spines claviform to glandiform with ribs or noded ornament.
Distribution
Middle Jurassic (Bajocian) to Recent; Cretaceous of Europe, Palaeocene of Europe, central Asia, the Caribbean and North America, Miocene of Sardinia, Recent of Japan.
Name gender feminine
Type
Cidaris clavigera Mantell, 1822, p. 194, by subsequent designation of Lambert & Thiery, 1910, p. 156.
Species Included
  • T. honorinae Cotteau, 1880; Bajocian-Bathonian, Europe.
  • T. propinquus (Munster, in Goldfuss, 1829); Oxfordian, Europe.
  • T. (Tylocidaris) velifera (Agassiz & Desor, 1846): Upper Albian to Cenomanian, western Europe.
  • T. (Tylocidaris) sorigneti (Desor, 1856); Uppermost Cenomanian and Lower Turonian, Europe.
  • T. (Tylocidaris) clavigera (Mantell, 1822); Upper Turonian to Upper Santonian, Europe.
  • T. (Tylocidaris) gosae Schlueter, 1892; Campanian, Europe.
  • T. (Tylocidaris) vexillifera (Schlueter, 1892); Danian, NW Europe.
  • T. (Tylocidaris) inexspectata Jagt & van der Ham, 1995; Maastrichtian, The Netherlands.
  • T. (Tylocidaris) hardouini (Desor, 1855); Danian, Europe, Ukraine, South USA.
  • T. sp. [T. walcotti Clark, 1915]; Thanetian, Eastern USA.
  • T. hemmoorensis Salah & Schmid, 1982; Maastrichtian, Germany.
  • T. (Oedematocidaris) asperula (Roemer, 1841); Cenomanian, Europe.
  • T. (Oedematocidaris) pleracantha (Agassiz & Desor, 1846); Santonian-Campanian, Europe.
  • T. (Oedematocidaris) baltica (Schlueter, 1892); Maastrichtian, Europe.
  • T. (Sardocidaris) ramondi (Leymerie, 1851); Maastrichtian, Spain; Lower Palaeocene, Kopet Dag.
  • T. (Sardocidaris) piae (Lambert, 1907); Miocene, Sardinia.
  • T. (Psychocidaris) ohshimai (Ikeda, 1935); Recent, Japan.
Classification and/or Status

Cidaroida; Psychocidaridae

Monophyletic
Remarks

T. (Oedoematocidaris) was established as a subgenus for forms with glandiform spines in which the cortical stereom hairs are dense and form a fused secondary overgrowth. Psychocidaris was established for the Recent species oshimai by Ikeda, who was unaware of the existence of the fossil Tylocidaris. It is here treated as a subgenus for forms with strongly flanged adoral spines. Sardocidaris is here treated as another subgenus for forms with rather elongate subambital spines with a pustular ornament. Tylocidaris (Tylocidaris) is restricted to forms whose spines are ornamented with beaded ribs or rows of small 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]. p. 1-101, pls 1-32.

Pomel, A. 1883. Classification methodique et genera des echinides vivants et fossils. Thesis presentees a la Faculte des Sciences, Paris. A. Jourdan, Alger, 131 pp.