The Echinoid Directory

Pyrina Desmoulins, 1835, p. 192

Diagnostic Features
  • Test ovate in outline, depressed in profile with rounded ambitus. Oral surface flat.
  • Apical system central, tetrabasal with four gonopores; genital plates subequal in size and all in contact. The posterior ocular plates abutting to the rear of the genital plates.
  • Periproct small, ovate and pointed adapically, inframarginal in position. Similar in size to peristome.
  • Ambulacra narrow, straight, pore-pairs small, simple, uniserial aborally and at the ambitus, becoming offset in lines of three adorally. No buccal pores.
  • Ambulacral plating pyrinoid throughout; every third element small and confined to the adradial border.
  • Interambulacra wide. Tuberculation of small uniform primaries with slightly sunken areoles scattered over plates; in between there is dense uniform granulation. No oral/aboral differentiation.
  • Peristome subcentral, slightly oblique with long axis running from Iamb. 3 to amb. 1, a little depressed.
  • No lantern or perignathic girdle in adults. Spines unknown.
Cretaceous (Middle Albian - basal Turonian), Europe.
Name gender feminine
Nucleolites castanea Brongniart, 1822, p. 336, 614, by subsequent designation of Wagner & Durham, 1966, p. U445.
Species Included
  • Numerous species have been assigned to this genus over the years.
Classification and/or Status

Irregularia; Echinoneoida, Conulidae.

Subjective junior synonym of Conulus Leske, 1778.


Differs from the type species of Conulus only in being less conical in profile and with a slightly less oral periproct.

Desmoulins, C. 1835. Actes de la Societe Linneenne Bordeaux 7, p. 192.

Smith, A. B. 1985. Cenomanian and Lower Turonian echinoiderms from Wilmington, Devon. Echinoids. Bulletin of the British Museum (Natural History) London (Geology Series) 42, 16-189.