Thursday, April 15, 2010

Prep update: Purisima Formation mysticete skull 3

Here are some pictures of the balaenopterid skull after preparation was completed. I finished preparation the tuesday before spring break. On wednesday and thursday I made the cradles, and friday loaded it into my car to drive back to California (on saturday).

Oblique posterolateral view of the Purisima balaenopterid skull.
Ventral view of the Purisima balaenopterid skull.Lateral view of the Purisima balaenopterid skull.The skull with the completed ventral cradle.The skull with both ventral and dorsal cradles.

On Friday of Spring Break, I met UCMP Curator Mark Goodwin at the oversize storage facility to drop the specimen off. UCMP is getting a new storage facility which will be a vast improvement over the current warehouse at the Clark Kerr campus (conveniently located right on the Hayward Fault).


Alton Dooley said...

Well done!

I can't tell from the photos; is the anterior end of the supraoccipital squared off, or does it come to a point?

Robert Boessenecker said...

Hey Butch,

The anterior tip of the SOS is indeed slightly squared off; a large skull figured by Barnes (1973) from the San Diego Formation potentially referable to this taxon has a slightly squared off SOP, about this stage or so, and very little parietal exposed.

How does this compare with your new cranial material of Eobalaenoptera?

Alton Dooley said...

Eobalaenoptera doesn't have the squared-off anterior margin of the supraoccipital that balaenopterids have, and it has little if any ascending processes of the maxillae (hard to tell, but it looks like your guy may have this). Eobalaenoptera does seem to have widely divergent zygomatic processes, and it also has large, swollen exoccipitals (this might be an apomorphy of the genus). Seems like your specimen is about the same size as Eobalaenoptera.

Of course, the Purisima is much younger than the Calvert (at least 7 million years).

Doug said...

awesome specimen.

Robert Boessenecker said...

Hey Butch,

I only recently saw the pictures of the new Eobalaenoptera material, and the referred cranium; beautiful material! There certainly is more material of the skull than was indicated when you guys described it. It does look *somewhat* similar to Protororqualus cortesii - unfortunately, that material is now destroyed, but I'm sure there's some similar material to Eobalaenoptera in Italy.

Alton Dooley said...

A lot of the Eobalaenoptera type material hasn't been completely prepared, and when we described it we didn't actually know we had that much of the skull. The skull had already weathered out and broken up when the specimen was first discovered. Weathered material at Carmel Church gets a hard crust that's almost impossible to remove. So for many years some of these skull fragments were encased in this crust, and we didn't even know it was skull material (we knew in 2004 that we had the condyles and bits of squamosal, but that's all). The pictures I posted on the blog is actually a sandbox reconstruction; I still haven't put the skull back together permanently because we may still have some unprepped pieces.

The other skull was actually collected in the early 1970's, but I wasn't aware of it until around 2006 (had I known about it in 2004, I'd have possibly have made it the holotype).

I've been working on a paper about those two skulls for awhile, maybe I'll get it out this year!