The Echinoid Directory

Agassizia Valenciennes, in Agassiz & Desor, 1847, p. 20

[= Agassisia Valenciennes, in Du Petit-Thouars, 1846 (original incorrect spelling); ?=Eoagassizia Grant & Hertlein, 1938, p. 115, type species E. alta A. Clark in Grant & Hertlein, 1938 ]

Diagnostic Features
  • Test ovate with no anterior sulcus at ambitus; rounded in profile.
  • Apical disc ethmolytic, with 4 gonopores; central.
  • Anterior ambulacrum narrow and weakly depressed adapically; pore-pairs specialised bearing small penicillate tube-feet; uniserially arranged.
  • Other ambulacra petaloid and weakly sunken, anterior petals considerably longer than posterior petals and flexed anteriorly; anterior column with rudimentary pore-pairs; anterior and posterior columns made up of the same number of plates.
  • Posterior petals shorter; weakly depressed and with both columns equally developed in type species (A. excentrica has reduced pores in the outer column).
  • Periproct on vertical, truncate face. Two or three subanal penicillate tube-feet.
  • Peristome large and D-shaped; labral plate not projecting strongly and peristome facing downwards.
  • Labral plate short and wide; not extending beyond first ambulacral plate; in broad contact with both sternal plates.
  • Aboral tuberculation fine, uniform and dense. Oral tubercles also dense and uniform.
  • Well-developed peripetalous fasciole passing a little below the anterior petals (ca. 3 plates below end) and inframarginal anteriorly, crossing plate 3 in anterior interambucrum. Lateroanal fasciole present.

Middle Eocene to Recent, North America, Caribbean, Middle East, East Pacific.

Shallow water silts and muds - infaunal.

Name gender feminine
Agassizia scrobiculata Val. Agassiz & Desor, 1847, p. 20, by original designation [Valenciennes reference to this genus the year before is a nomen nudum].
Species Included
  • A. scrobiculata Valenciennes, 1846; Recent, west coast of central America, Galapagos.
  • A. algarbiensis Ferreira, 1961; Miocene, Portugal.
  • A. excentrica Agassiz, 1869; Recent, Caribbean.
  • A. powersi Kier, 1972; Miocene, Dam Formation, Saudi Arabia.
  • A. wilmingtonica Cooke, 1942; Middle Eocene, South East USA.
  • A. persica Clegg, 1933; Middle Miocene, Qatar.
  • A. lovisatoi Cotteau, 1895; Lower and Middle Miocene, France, Sardinia.
  • A. alta Grant & Hertlein, 1938; Eocene, California USA.
Classification and/or Status

Spatangoida, Paleopneustina, Prenasteridae.

Presumed monophyletic.


Differs from Anisaster in having no respiratory tube-feet (and associated pore-pairs) in the anterior column of the anterior paired petals. Prenaster also lacks a frontal groove, but its apical disc lies much closer to the anterior border and the paired anterior petals diverge at almost 180 degrees.

Agassiz, L. & Desor, E. 1846-1847. Catalogue raisonné des familles, des genres, et des espèces de la classe des échinodermes. Annales des Sciences Naturelles, Troisième Série, Zoologie: 6 (1846), 305-374, pls 15-16; 7 (1847), 129-168; 8 (1847), 5-35, 355-380.

Mortensen, T. 1951 A. monograph of the Echinoidea. V. Spatangoida 2. C. A. Reitzel, Copenhagen.

Kier, P. M. 1972. Tertiary and Mesozoic echinoids of Saudi Arabia. Smithsonian Contributions to Paleobiology 10, 1-242.

Kier, P. M. 1980. The echinoids of the Middle Eocene Warley Hill Formation, Santee Limestone and Castle Hayne Limestone of North and South Carolina. Smithsonian Contributions to Paleobiology 39, 1-102.