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

Big 2″ bitten echinoid with healing.  Unusual.

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 localities in California.  Hundreds can be collected in a day which allows for growth series to be constructed and odd examples to be examined in a short time.  Occasionally, specimens showing healed injuries are found.  They exhibit highly-irregular outlines but with the edges unbroken.  This sand dollar was perhaps saved by a rogue wave or its attacker was otherwise distracted.