this week in urban paleontology

Busy, busy excavators we have been!


The photo above shows the 50+ fossils we've measured out over the last two weeks. Extremely note-worthy finds include:
- a metacarpal (hand bone) of a Capromeryx (an extinct and fairly rare species of dwarf pronghorn)
- numerous saber-toothed cat and dire wolf ribs
- at least 6 sub-adult thoracic vertebrae (vertebrae from the rib cage) of a saber-toothed cat. We think they're all from the same individual animal! They were all found in the same 50cm X 50cm x 25cm area of the fossil deposit, and all appear to be about the same age. This is the sort of semi-articulation or association that we've been so excited about finding, because we very rarely (if ever) find it in Pit 91.
- part of a dire wolf skull
- at least four coyote jaw pieces
- a sloth sternal rib (a rib from the front of the ribcage, rather than the back. If you can't find one in your own torso, don't worry -- humans do not have sternal ribs. If you do find one in your own ribcage, please let us know! We'd be extremely interested in studying you...)
- the astragalus (an ankle bone, AKA the talus in humans), scapula, and pelvis (pictured below) of an American Lion

the measured pelvis, in it's natural environment: a metal bucket and a plastic bag. more on this tomorrow

What does this mean? Well, we've found not just one, but TWO of Rancho La Brea's rarer species (the American Lion and the Dwarf Pronghorn) in our first month of digging, not to mention another unique instance of fossil association! This first deposit is already adding to our knowledge base, and these discoveries bode well for the rest our excavation.

And remember this?

(l to r: sloth left scapula, sloth right scapula, ryan)

it now looks like this:

(l to r: dustpan, sloth left scapula, yet another tibia, sloth rib, sloth right scapula, michelle)

Progress!

The story thus far

Between February and July of 2006, 16 ginormous fossil deposits were found underneath what used to be Ogden Dr. (and what is now LACMA’s fancy new underground parking garage). With construction deadlines looming and fossils constantly appearing underfoot, Robin Turner over at APRMI came up with a brilliant plan: rather than halting construction for an indefinite period of time to excavate each and every fossil, she boxed the deposits up as if they were colossal oak trees, lifted them out of the earth with an equally colossal crane, and set them aside for later study. These 16 deposits took up 23 tree boxes, and thus….

"PROJECT 23" WAS BORN!
(Well, “Project 23 plus 2 fossil trees, 327 buckets, a whole bunch of film canisters and plastic baggies filled with other assorted fossils, and 20 plaster jackets containing the bones of one semi-articulated mammoth with complete tusks," but you get the idea, right?)

So what's in these boxes? We don't know! It's a mystery! We won't know until we open up them up! It's like a paleontological Christmas! If the deposits are anywhere as dense as Pit 91, we could have literally hundreds of thousands of fossils on our hands. And if we were to include all of the microfossils (bug parts and tiny shells) in that estimate: maybe even millions.

That having been said, we do know this:

This is the top of Deposit 1, and these are the bones of a sabertoothed cat. But furthermore, these are the semi-articulated bones of a sabertoothed cat: a hip bone and a lower hind leg, to be exact. Further furthermore, we know that these are the bones of a fairly young sabertoothed cat; since the epiphyseal line between the main part of the bone (the diaphysis) and the end of the bone (the epiphysis) is visible, we know that the animal was young enough that his bones hadn't finished fusing. We rarely, if ever, find this sort of articulation in Pit 91. The fact that we're finding this sort of thing right off the bat is fairly-to-extremely awesome.

Further further furthermore:

This is the scapula (shoulder blade) of a giant ground sloth (and Ryan's feet) (please note the tar-y socks). Giant ground sloths are AMAZING and made entirely of WIN, and their presence in this first deposit is an extremely good omen.

More soon...