Whale update 2

We’re still working on the unidentified baleen whale from Carmel Church, which was first opened last March. The image above shows the second of four jackets that contain this skeleton.

The front of the whale is toward the top of the image, and you’re seeing it from the bottom (the whale was belly-up on the seafloor), so the left side of the picture is the right side of the whale. You can see the ribs arranged on each side, and eight vertebrae (the circular objects) going down the middle.

This is an unusual type of preservation, in which the bone are in the correct general regions of the body (left, middle, and right), but are jumbled within those areas. In contrast, we typically either get articulated skeletons (with the bones pretty much in life position), or associated disarticulated skeletons, in which most of the bones are there, but they’re completely disorganized.

Bronwyn and Whitney, who have been working on this jacket for several months, completed their internships last week, after four months of excellent work. They finished up by “vandalizing” the lab whiteboard:

Larry is their nickname for the whale they’ve been working on. See Whitney’s shark here. Cera the animatronic Triceratops was temporarily on exhibit during Dino Day.

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6 Responses to Whale update 2

  1. Anonymous says:

    Wow! That sure takes a long time. I was wondering, what could cause the unusual preservation you found in that whale? Do sharks shake their prey like dogs do and rattle the bones around?

  2. Alton Dooley says:

    Actually, I’m not sure how it preserved this way. Whales usually seem to go one of two ways. One is that they stay mostly intact–there is a lot of connective tissue in a whale’s body that holds it all together. The flippers might get pulled off (finding complete flippers is rare), but the vertebrae and ribs are left mostly intact.

    The other (more common) option is that they float around with their skin mostly intact and kind of turn to goo on the inside. This lets the bones shift around under the skin, and when they finally sink to the bottom you end up with a complete jumble of bones. Often large parts of the skeleton will be missing (including the flippers, sometimes the lower jaws or head, or large numbers of ribs and vertebrae.) This is consistent with shark scavenging, also–they tend to tear things apart, so you just find scattered pieces.

    At first glance this whale seems to have the jumbled bones bones pattern, but there’s a certain amount of order to the bones. We also have the skull with both haves of the lower jaw, and at least half of the vertebrae (no flippers so far), so it’s pretty complete compared to the typical jumbled skeleton.

    The skeleton also shows a ton of evidence of scavenging by sharks, much more than usual for Carmel Church specimens. So there was certainly a lot of scavenging, but why didn’t the sharks tear it apart completely? And how did they move all the vertebrae out of position but mostly leave the ribs in place? Some of the vertebrae are way out of position–we found one neck vertebra way down near the front of the mouth, and a back vertebra (not the next one in the series) right next to it.

    So, basically I’m not sure. One thing I’ve considered is that this whale might have had an unusually large amount of connective tissue along its sides. Dolphins, at least, have sheets of ligaments tying their ribs together, that might stabilize their body during swimming. If this whale had something like that it might have held the ribs more-or-less in place while the vertebrae shifted around in the rotting carcass (a nice image, I know.)

    Of course, this is just speculation at this point, but that’s part of the fun of science!

  3. Doug Shore says:

    Yeah, San Diego museum had a display several years ago talking about how whales can become a “floating bag of bones”. But Carmel Churche’s whales are a bit of a mystery, eh?

  4. Alton Dooley says:

    Yes, Carmel Church’s whales are strange, and this particular whale is only part of it. We have other skeletons that show a whole variety of different preservational styles, that should be more-or-less mutually exclusive. Yet we find them all mixed together, and we’re fairly sure that the bonebed was formed pretty quickly. That’s one of the big mysteries we’re trying to solve there; we already have a long list of hypotheses that we’ve rejected.

  5. Doug says:

    Like what? What were the problems with them? Carmel Church reminds me of the Hancock Mammal Quarry in Oregon. Well, at least they figured out how it was formed.

  6. Alton Dooley says:

    Well, to put it as briefly as I can:

    On the Atlantic Coastal Plain unconformities in the stratigraphic section are typically marked by time-averaged pebble lags that are rich in reworked bones and teeth. We have that sort of thing at Carmel Church–in fact, probably 50% of the sharks’ teeth we find are reworked from older units.

    However, we also have a whole range of other types of preservation of specimens that have not been reworked, including:

    Isolated bones
    Bones with evidence of stranding (cracking and abrasion)
    Isolated skulls
    Disarticulated, associated partial skeletons (5-10 bones)
    Largely complete, disarticulated skeletons (like the whale above)
    Partially complete, mostly articulated skeletons

    None of these is unique. However, each one indicates a different preservation history, and we find them all mixed together (we’ve only excavated a few thousand square feet). Moreover, while we have good evidence that the whales didn’t all die at the same instant, we do fairly good geological evidence that the bonebed doesn’t represent a huge amount of time. So, is it some kind of catastrophic death assemblage? We’ve toyed with that possibility, but we have not come up with any good evidence to support it. Most marine bonebeds (Sharktooth Hill is a good example) are attritional deposits that formed over a very long period of time, and they have a different taphonomic signature.

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