The Echinoid Directory

Eurhodia Haime in d'Archiac & Haime, 1853, p. 213

[=Ravenelia McCrady, 1859, p. 283, type species Pygorhynchus rugosa Ravenel, 1848 ]

Diagnostic Features
  • Test of medium to large size, elongate, low to moderately inflated, flattened adorally.
  • Apical system monobasal, with four gonopores.
  • Petals equal in length, broad, slightly bowed and tapering distally but remaining open.
  • Peristome longer than wide, with vertical-walled vestibule.
  • Periproct marginal to supramarginal, transverse; test slightly projecting above and weakly indented beneath.
  • Bourrelets: basicoronal plates short but with slight swellings; dense tuberculation extend laterally along bourrelets as well as on vertical-walled entrance to peristome.
  • Phyllodes broad, single pored, with two series of pores in each half-ambulacrum. Sphaeridial pits well developed, forming a double series immediately inside the inner series of pores.
  • Tubercles perforate, considerably larger adorally than adapically, and with sunken areoles.
  • Naked and pitted adoral zones both anterior and posterior to the peristome.
  • Eocene of India, Australia and North America.
Name gender feminine
Eurhodia morrisi Haime in d'Archiac & Haime, 1853, p. 214; by monotypy. Syntypes: BMNH E42343 & E42345.
Species Included
  • E. morrisi Haime in d'Archiac & Haime, 1853; Lower Eocene, India.
  • E. rugosa (Ravenel, 1848); Middle Eocene, USA.
  • E. australiae (Duncan, 1877); late Eocene, Australia
Classification and/or Status
Irregularia; Cassiduloida; Cassidulidae.

According to Kier (1962, p. 214) Eurhodia morrisi has previously been credited to d\'Archiac 1850, p. 248, however, it is a nomen nudum in this reference and therefore must date from Haime, 1953.

Eurhodia has all the diagnostic characters of the Cassidulidae including the broad, naked, pitted sternal area, both in front and to the rear of the peristome. It is not clear to us why Kier (1962) assigned this genus to the Pliolampadidae.

Eurhodia is distinguished from other Cassidulidae by its elongate shape, with a longer than wide peristome.

Archiac, E. d'  & & Haime, J. 1853. Description des animaux fossiles du groupe Nummulitique de l’Inde, 373 pp., 36 pls. Gide and. Baudry, Paris.

P. M. Kier. 1962. Revision of the cassiduloid echinoids. Smithsonian Miscellaneous Collections 144, (3), 262 pp.