Dendraster venturaensis
Echinoid
Late Pliocene
Las Posas Formation
South Mountain, Ventura County, California, USA

Excellent 96mm big echinoid.

Dendraster is a genus of sand dollar (an echinoderm group) that appeared late in the Miocene and still lives today.  Dendraster venturaensis is extinct and larger than D. gibbsi (also extinct) and tends to be larger than the modern species, D. excentricus.

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