Hall, C. A. Jr. 1962. Evolution of the echinoid genus Astrodapsis. University of California Publications in Geological Sciences, 40(2), 47-180.

177452

Hallr, C. A. J.

1962

40(2): 47-180

Publication

https://archive.org/details/evolutechin00hall

Astrodapsis specimens from several areas of California seem on casual observation to be morphologically distinct from others in the same bed or at the same horizon, but upon closer scrutiny and comparison can clearly be shown to represent members of one variable population. Many of the previously described species are morphologically intergrading taxa that come from the same horizon, and thus represent one population, i. e., a group of freely interbreeding individuals at a locality. Because of these relationships the echinoid genus Astrodapsis is revised: the 59 named species, subpecies, and varieties are reduced to 12 species, These species include, from the oldest to the youngest, A. brewerianus, A. diabloensis, A. pabloensis, and A. cierboensis forming one supraspecific-taxon; A. davisi, A. antiselli, A. spatiosus, A. arnoldi, A. fernandoensis, and A. peltoides forming another; and the closely related A. whitneyi and A. jacalitosensis, a third. Statistical analyses strongly support the reduction in number of species and subspecies and also lend support to the belief that these 12 species have real stratigraphic value. Astrodapsis is a late middle Miocene to early Pliocene genus that is apparently restricted to California.

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