Reply To: K-5 lesson plans–Santa Cruz, California

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Bobby Boessenecker

Hi @bmacfadden – I’ll be visiting California for the holidays Dec 17-Jan 4, and might have time for a trip to pick up some supplementary fossils for your educational packages. Thalassinidean shrimp claws are fairly easy to find, but only within two bonebeds, which take a bit of practice to spot – I’m happy to pick up a bunch for you. The Dendraster request will be tough to fill, simply because A) they are present only within vertical cliff exposures that are illegal to dig into (boulders on beach OK, but cliff is off limits) and B) the matrix is notoriously difficult to remove and sort of requires abrasive preparation and sanding/polishing.

Again about the sharks – the exhibit at the SC Natural History Museum is on sharks from the stratigraphically lower Santa Margarita Sandstone in Scotts Valley – not the Purisima Formation. Carcharocles megalodon is only known from two specimens in the Purisima, one of which is in a private collection and the other of which is a specimen I collected at a separate locality that is geochronologically older – so in my opinion, it’d be better to stick with Carcharodon carcharias teeth rather than C. megalodon teeth for the kits. The sharks that are by and large the most common are Carcharodon carcharias, Hexanchus sp., and Myliobatis sp. Actually, Myliobatis is far more common than all other elasmobranchs combined. Cetorhinus gill raker fragments are found semi regularly; a single tooth has been collected. Alopias and Carcharinus are known from the Purisima Formation at Capitola by a single tooth each (SCMNH collections); I’ve found additional isolated teeth of Raja, Galeorhinus, and Dasyatis by screening bonebed matrix from Capitola. And that’s effectively the extent of the elasmobranch fauna of the Purisima at Capitola. I hope that helps.