Saturday, January 1, 2011

Associated dolphin vertebrae

Sorry for the delay in posting; I've been enjoying a lazy winter break so far. Over thanksgiving break, I spent some time at a Purisima Formation locality which I had just received a new collections permit for. I went out with my friend Chris Pirrone to this new locality. Unfortunately, there hadn't been much storm activity since the summer. Storm activity achieves two things: it washes off a ridnd of weathered clay minerals off (in addition to algae), and it transports sand from the beach to offshore bars, which during fairweather, are slowly eroded and the sand is transported back onshore.
After a while of not finding anything, I spotted these three associated vertebrae - from some kind of a small odontocete. Two of the vertebrae lie in near articulation, and the other is slightly displaced.

Here's a closeup view of the specimens.

Chris Pirrone applies vinac to the fossil vertebrae.

We collected these three vertebrae, but it was too cold to stay and dig through the sediment for more bones. I'm sure there are more; some forelimb or cranial elements would be great. I'll return to the locality once some more storm activity cleans off the cliff exposures.

During the course of my taphonomic research of fossil vertebrates in the Purisima Formation, I've found that associated vertebrate remains (two or more elements which in life are only joined by soft tissue) are extremely rare in the shallow marine fossil record (if the Purisima Formation is taken to be a representative shallow marine deposit). Indeed, this is one of a couple dozen specimens showing any degree of association or articulation.

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