Saturday, March 17, 2012

Dispatches from the field: Baja California, Pt. 3

Today we set out to collect the partial mandibles that were next to the skull that we collected yesterday. We are still not sure which taxon it is (we have some ideas) but to know for sure we'll have to wait until the skull is completely freed from its rocky tomb. But first, we decided to do some prospecting to the east of where the sirenian skull was.

We didn't find anything in the units east of the sirenian skull site so we decided it was time to collect the mandibles. Also, there were some postcranial material that we had started to collect, but with the excitement of finding a skull, they had been neglected. Well, not any more. After this we were supposed to be done with this locality, and could get ready to head out to other localities we've plan to go.

As it sometimes happens, our plans changed. After collecting the fossils we set out to review the stratigraphy of the section we've been prospecting, actually, some of us, Larry and Fernando, had done it, and they wanted our opinion on it, and we could also know exactly how to refer to the units where we were collecting our specimens. At the beginning, near our camp, I stayed behind digging a rib, from one of the lower beds of the formation, after a while I stopped and joined the others, but keeping in mind that on the way back I wanted to collect the rib. So, on the way back, I started digging the rib and to my surprise found something even better next to it. Part of a sirenian skull! Another one!

The fragment that I found consists of part of the left maxilla (see the molar in the maxilla, above), and as I and some of the others kept digging more stuff kept coming out. As the sun settled we kept finding more and more bones along this one bed, next to the sirenian maxilla there were other cranial material most likely belonging to the same individual, obviously the sirenian was juvenile as the skull is disarticulated. Other fossils that we've collected so far include a baleen whale vertebra and some dolphin vertebrae, so in one small spot we've got three different marine mammals. It was another good day of collecting today!

Previous entries in this series:

Dispatches from the field: Baja California, Pt. 1

Dispatches from the field: Baja California, Pt. 2

Fieldwork in Baja California was made possible through an NSF EAR grant to D. P. Domning & L. G. Barnes. The text in these posts reflect my own opinion and not those of the granting agency or institutions to which I’m affiliated.

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