Bobby Boessenecker
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Hi all,
One possibility for this bone is a phalanx of a primitive mysticete or odontocete. The flattened articular surface is characteristic of Neoceti. Archaeocetes like Eocene basilosauridae (e.g. Dorudon atrox, shown here – from Uhen, 2004) have quite narrow elongate metacarpals and phalanges, unlike extant Neoceti.
This is surprisingly skinny for a neocete, but we’ve got many primitive Neoceti from the Oligocene of Charleston without well-preserved flippers. Most actually lack flippers, so anything is possible.
Hi all, sorry for the delayed response! Thanks for tagging me, Eleanor. Definitely from a large cetacean, and if Pliocene or late Miocene, baleen whale is the most likely possibility. Unfortunately as @lcone stated above, it’s not really possible to say much more about the specimens.
HOWEVER – please keep your eyes peeled for skull fragments and earbones! South Africa has a limited but very critical assemblage of marine mammals that is poorly documented, but efforts by my colleauge Romala Govender are changing that. If you find anything further that is more diagnostic (i.e. skull bits and earbones), then I strongly recommend contacting Dr. Govender at Iziko Museums.
Yeah thanks, the age information is pertinent for those of us unfamiliar with local stratigraphy. Again, I’m not a reptile guy, but you should look into comparisons with sea turtles as well. Don’t know anything about Eocene crocs.
Well it’s procoelous (or possibly amphicoelous) so the most likely options are mosasaur or crocodilian. I have a hunch it’s the former, but I’m not a reptile guy!
Hi Laura,
Unfortunately I’m on the east coast and don’t really have access to that locality. However, I suggest getting in touch with local collector Chris Pirrone (cpirrone [at] pirronelaw.com) who is one of my avocational colleagues in the bay area, and knows the local stratigraphy quite well.
Cheers, Bobby
Hi all and @bmacfadden, I had a successful two hour visit to Capitola yesterday and found some articulated Cetorhinus vertebrae, a dermochelyid turtle shell element (leatherback) as well as the full compliment of calianassid shrimp claws (7-9 specimens) and Dendraster sand dollars (about 7 specimens) you guys need. The shrimp claws are easy enough to put in the mail, but a bit of matrix is still in place on the Dendrasters; I can try and remove as much as possible.
Admittedly the bed which the calianassid claws are so common in was barely exposed owing to a lack of cliff collapses over the past 6-8 years or so; there hasn’t been a good fall since 2007.
Rather than mailing them, could I leave them at your future address in Santa Cruz?
Also for some weird reason I can’t see any text in this text box while I’m typing – the text color comes in as white. Any tips or is it just broken?
Hi @bmacfadden, sure thing – I may be going to Santa Cruz tomorrow, and if so, will collect some calianassid claws; or, if not tomorrow, sometime later in the week. Any other requests for other invertebrates? I could probably include some whale bone fragments as well.
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.
Hi all,
Bruce invited me to join the forum – I’ve done quite a bit of field work in the Purisima Formation, mostly going after fossil vertebrates (my focus is marine mammals) but I am very familiar with the inverts as well and my master’s thesis (published last year in PLOS One) considers the marine vertebrate taphonomy of the unit. Capitola is one of the taphonomically more informative localities as it spans inner-middle shelf depositional settings. Also, I’m quite proud of the fact that in 2004 I helped others in Santa Cruz county stop a seawall from being built that would have covered over this entire locality – so I am absolutely pleased to hear that you all have started using it as a “teaching laboratory” for educational purposes.
Bruce, I see plenty of Anadara trilineata in that collection of mollusks you received. I may be able to make it down to Capitola while I’m home for Christmas, but more likely than not I’ll ask a couple of my buddies in the area who are dedicated, informed amateurs to collect some of the other more common invertebrates.
As for sharks: rare Carcharodon carcharias teeth can be found in a couple of the horizons, but no Carcharocles megalodon; only a single tooth has been collected from the Purisima, and I collected it from a different locality that is geochronologically older (~7 Ma, as opposed to the ~2.5-5 Ma section at Capitola).
I am more than happy to answer any questions you guys have – please pick my brain! This is one of my favorite localities, and I’ve been visiting the spot since I was in high school ~14 years ago. Cheers, Bobby
