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The Echinoid Directory

Prenaster Desor, 1853, p. 279

[= Saviniaster Lambert, 1911, p. 33, type species S. miqueli Lambert, 1911; = Parabrissus Bittner, 1880, objective]

Diagnostic Features
  • Test ovate without anterior sulcus; posterior face truncate.
  • Apical disc ethmolytic with four gonopores; strongly anterior of centre.
  • Anterior ambulacrum flush aborally; narrow; pore-pairs small.
  • Paired ambulacra petaloid aborally; weakly sunken. Anterior petals widely divergent, almost at 180 degrees; pore-pairs slightly flexed distally; parallel with little perradial space between columns. Posterior petals similar.
  • Plastron plating with short labrum and long, symmetrical sternal plates. Episternal plates biserially offset.
  • Periproct high on posterior truncate face.
  • Peripetalous fasciole indented behind anterior paired petals and crossing ambs about 3-4 plates below the end of the petals. Lateroanal fasciole present. Fascioles merge behind anterior petals and pass subambitally around the anterior.
Distribution
Lower Eocene to Recent, Europe, North Africa, Madagascar, Australia, Japan.
Name gender masculine
Type
Prenaster alpinus Desor, 1853, p. 279; by original designation.
Species Included
  • P. alpinus Desor, 1853; Lower and Middle Eocene, southern Europe (Spain to Bulgaria), North Africa, Madagascar.
  • P. boninensis de Loriol, 1902; Middle Eocene (Lutetian), Bonin Islands.
  • P. migueli Lambert, 1911; Eocene, France.
  • P. enodatus Chesher, 1968; Recent Caribbean.
  • P. excentricus (Wright, 1855); Upper Miocene, Malta.
  • P. jeanneti Pijpers, 1933; Late Eocene, Sardinia.
  • P. parvus Palmer, in Sanchez Roig, 1949; Late Eocene, Cuba.
  • P. aldingensis Hall, 1907; late Middle to early Late Eocene, southern Australia.
Classification and/or Status

Spatangoida, Paleopneustina, Prenasteridae.

Presumed monophyletic.
Remarks

Distinguished from Agassizia by its anterior petals being almost at 180 degrees to each other, and by having pore-pairs in the anterior column of anterior petals equally as developed as those in the posterior column.

Brissomorpha is very closely related, having a similar fasciole pattern and petal arrangement.  It differs in having a much larger periproct that is inframarginal, with the posterior face strongly undercut.

Kroh, A., 2005: Catalogus Fossilium Austriae. Volume 2 Echinoidea neogenica. lvi+202 pp., 82 pls., 94 figs., 11 tabs., Österr. Akad. Wiss., Wien