Fossil Friday – camel lumbar vertebra

While we only have one well-preserved skull of the extinct camel Camelops hesternus from Diamond Valley Lake, we have a large number of post-cranial remains.

The bone shown above is a lumbar vertebra, seen in anterior view. This seems to be the 7th lumbar, the last one in the series before the sacrum (which was also recovered from this individual, along with several other bones). The prominent curved structures above and on each side of the neural canal are the prezygopophyses. These articulated with the postzygophyses of the 6th lumbar. The strong curvature would largely lock the two vertebrae together, resulting in a relatively inflexible lumbar region.

Here is the posterior view, with the postzygophyses visible:

And the left lateral view:

The neural spine is broken on this specimen, as are the transverse processes (the right one is missing entirely). The broken surfaces are packed with sediment and abraded, indicating that they were broken off before burial. That is interesting considering that there are multiple associated bones with this specimen; that makes it less likely that the bone was damaged by, say, washing down a river. Could this damage have been caused by scavenging? I tried looking at the bone with low-angle light, which sometimes helps reveal bite marks on the surface:

Sure enough, these are apparent bite marks on the bottom edge of the centrum. Below is the preserved part of the left transverse process, with apparent bits marks along its entire length:

There are other possible bite marks scattered across this vertebra. Moreover, close examination also revealed possible insect feeding traces in various places, including on one of the prezygapophyses:

These possible traces seem to be extremely common on bones from Diamond Valley Lake, possibly occurring on half or more of the large specimens. Clearly, besides studying the bones themselves, there’s a lot of potential in the DVL trace fossils as well.


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