Dendraster gibbsi
Echinoid
Late Pliocene
Etchegoin Formation
Kings County, California, USA

43mm bitten echinoid.

Dendraster is a genus of sand dollar (an echinoderm group) that appeared late in the Miocene and still lives today.  The species, D. gibbsi, is common at some Pliocene localities in California.  Occasionally, specimens showing healed injuries are found.  They exhibit highly-irregular outlines but with the edges unbroken. 

The severity of the damage in this specimen testifies to a narrow escape from death. Perhaps the predator was interrupted by an incoming wave or the attack of one its own predators.