Description

Dendraster venturaensis

Pliocene

Las Posas Formation

South Mountain, Ventura County, CA USA.

Excellent 87mm big echinoid.

Dendraster is a genus of sand dollar (an echinoderm group) that appeared late in the Miocene and still lives today.  D. venturaensis is a Pliocene species that apparently died out by the Pleistocene.  Specimens tend to be larger than those of the modern species, D. excentricus.

Specimens were easily available on the market thirty years ago and then they seemed to disappear.  Here’s one from a small group recently acquired.