More sperm whales

Some time ago I posted a photo of the tooth shown on the left above when I was talking about sperm whales from the Calvert Formation. I didn’t mention at the time that it was the only known tooth from the Calvert Formation at Carmel Church. (There is a sperm whale from the St. Marys Formation at Carmel Church.) However, that’s no longer the case.

Today I was showing a high school student around the collections as part of a job shadow program. Since I’ve been going through the type Eobalaenoptera material in preparation for my SEAVP talk I decided to show her some of the material in those cases (it has never been completely prepared and sorted). While scanning over this material I spotted the tooth on the right above, the second Calvert sperm whale tooth identified from Carmel Church (although it was the first one collected, by 15 years!). Like the other tooth, it’s a fairly typical “Orycterocetus”-type tooth, small and with no enamel.

The next picture is intended to intrigue Brian Beatty, who has done some work on tooth wear. The wear patterns in these two teeth are quite different. The 2006 tooth (on the left) has a strong curved wear facet along one side of the tip of the tooth, while the 1991 tooth (on the right) has a broadly worn tip, which I think is more similar to the wear seen in modern sperm whales.

Of course, as can be seen in the Rappahannock sperm whale (as well as other large-toothed sperm whales like Zygophyseter) the wear patterns on physeteroid teeth can vary substantially in a single individual from one part of the mouth to the other, so this is likely not of any taxonomic significance. However, it may be useful in determining feeding habits in these whales, especially once a larger sample size is collected.

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This entry was posted in Carmel Church odontocetes, Carmel Church Quarry, Chesapeake Group and tagged . Bookmark the permalink.

7 Responses to More sperm whales

  1. Brian Beatty says:

    You got my attention!!!
    Hmmm… I believe that this illustrates something about odontocete tooth wear in general that Alex Werth and I are getting ready for submitting. Though we are putting it together with tooth sharpness, spacing, diet, and enamel microstructure, the gross wear part is interesting in its own right. Maureen O’Leary and Mark Uhen pointed out some interesting features of early whale tooth wear, particularly the formation of a shearing facet. This is partly due to tooth spacing and interdigitation, and this can be sen in varying degrees among modern odontocetes. The rounded wear facets on crowns appears to be something else entirely, and the only fitting explanation seems to be that food and/or exogenous grit is causing it.
    Ok, enough technicalities…. what is perhaps weirdest about this tooth is that if that facet is due to interdigitating wear from an opposing tooth, then did this sperm whale have large, lower AND upper teeth? I guess many fossil taxa did, but when one considers modern Physeter, it just seems odd.
    Way cool, Butch, thanks for sharing that!!!

  2. Interesting specimens!! A similar tooth with a wear facet (although not as extreme) was described from the Burdigalian of Cuba by MacPhee et al. (2003). They compare it with Orycterocetus, unfortunately that (and another tooth) is all there is in terms of fossil cetaceans from the Greater Antilles :/

  3. Alton Dooley says:

    Orycterocetus was originally erected (by Cope, I think) based on an isolated tooth. Kellogg later referred some skulls from the Calvert to Orycterocetus, and those skulls have upper sockets, although no teeth were preserved in those specimens. Aulophyseter, on the other hand, seems to have had Orycterocetus-type teeth in the lower jaw only (although there is a slight upper dental groove, IIRC).

    As I think about it, though, I think this is the only small sperm whale tooth I’ve seen with an occlusive wear facet, although they’re common in large, enamel-crowned sperm whale teeth.

  4. Alton Dooley says:

    And, while I’m writing my comment, someone mentions another tooth with that type of wear facet!

  5. shrieking denizen says:

    Hello Dooley. Someone from the team was on the local radio this morning, I thought that might interest you. Your April 1’s legless otter was quite funny by the way; the squeleton was a nice touch.

    “Canadian scientist Natalia Rybczynski’s team finds an early pinniped ancestor in the high Arctic, on Devon Island. It looks like something between an otter and a seal. A 3-D model will be on display at the Canadian nature museum this summer.

    http://nature.ca/puijila/index_e.cfm

    The beeb has made a blurb on it.
    http://news.bbc.co.uk/1/hi/sci/tech/8012322.stm

  6. Alton Dooley says:

    Hey, sd, good to see you here! Glad to hear you liked the wooly snakes.

    There’s a lot of discussion on the paleo email groups about this new critter, Puijila, from the early Miocene of Canada. I haven’t read the paper yet, but they’ve certainly got a lot of material in this specimen. It’s very intriguing that they found it in a fresh water deposit, since there aren’t a lot of those around. I’m assuming the authors list some specific characters in Puijila to link it to the seals rather than some independent lineage of aquatic carnivore. Certainly a factor to consider, though, will be the age. At only 23 million years, it seems a little on the young side to be a direct pinniped ancestor, although that doesn’t eliminate it from being close to the ancestor.

    I seem to recall seeing an undescribed mustelid in a museum somewhere, from the Green River Formation. The Green River is a lake deposit, and is much older (Eocene). I’m not suggesting that as a pinniped ancestor, just pointing out that there seem to have been a number of aquatic and semi-aquatic carnivore lineages, so clearly linking Puijila to the seals will be key.

  7. ScienceSpouse says:

    Something about the typeface causes me to read “pinniped” as “pimped”.

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