The Echinoid Directory

Contributed by Andrew Smith, May 2007

Barnumia Cooke, 1953, p. 29

Diagnostic Features
  • Test inflated and rounded; tallest at apical disc; slight posterior heel; faint anterior sulcus.
  • Apical disc ethmophract, 4 gonopores; all genital plates similar in size.  Positioned close to the anterior.
  • All ambulacra petaloid; more or less flush; open distally.
  • Plastron plating not discernable on any specimen.
  • Peristome small, circular to wekaly subpentagonal; very slightly depressed; situated about one-third test length from anterior; 2-3 phyllode pores in each ambulacrum surrounding peristome.
  • Periproct supramarginal, on steeply sloping posterior face.
  • Peripetalous fasciole passing several plates below the ends of the petals; passes beneath the ambitus around the anterior. No subanal fasciole.
  • On aboral surface primary tubercles set in a dense matrix of granules.
Distribution Upper Cretaceous (?Campanian), Guatamala.
Name gender feminine
Type Barnumia browni Cooke, 1953, p. 29, by original designation. USNM 108407A.
Species Included Only the type species.
Classification and/or Status

Spatangoida, Hemiasterina, Aeropsidae.

A junior subjective synonym of Homoeaster Pomel, 1883.
Remarks I have restudied the type.  This closely resembles other species of Homoeaster in apical disc structure and fasciole development.  It differs primarily in having ambulacra with more developed pore-pairs than in any other species.

Cooke, W. B. 1953. American Upper Cretaceous Echinoidea. Geological Survey Professional Paper 254-A, 1-44, pls 1-16.