Potomac sperm whale completed

I’ve finally completed the preparation work on the small sperm whale jaw from Westmoreland County brought to the museum by John Parker last month. The jaw was crushed flat in the sediment, and required a fair amount of reassembly to restore it to three dimensions. As is clear in the image above, some pieces of the very thin bone at the back end of the jaw were missing, but considering that the bone there is only about 1 mm thick it’s preserved pretty well.

Here’s the medial side of the jaw, with the posterior end of the mandibular canal visible above the center of the scale bar:

This is a quite small sperm whale. The difference is really noticeable if it’s compared to the slightly younger Rappahannock River sperm whale:

What’s really fascinating about the Potomac River specimen is its teeth. Five teeth were found in situ (still in the sockets):

These teeth all have large occlusion wear facets on their posterior margins, caused by rubbing against the upper teeth (and showing that this whale, in fact, had upper teeth). An additional 10 teeth were found loose in the sediment (eight of them are shown below). Almost all of these have wear facets on their anterior margins, suggesting that they were upper teeth that fell out of the skull.

One tooth in particular was very interesting, because of the huge bulge located near the middle of the tooth:

Seen end-on, you can see that the bulge in the tooth is associated with a small puncture (below). I think this tooth suffered a puncture injury and developed an abscess.

All in all this is an interesting specimen that’s going to give us a lot to think about, and I’m thrilled that we were able to add it to the VMNH collection. I’d like to again thank John Parker, who collected the jaw and brought it to the museum, and William Tune, the landowner who allowed John to collect on his property and donated the specimen to VMNH.

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8 Responses to Potomac sperm whale completed

  1. Doug says:

    wow, it almost look like a killer whale jaw. If the break wasn’t so obvious you could have fooled me. And it’s so small. Any chance this could be a juvenile?

  2. Alton Dooley says:

    Judging from the amount of tooth wear, I’d say it’s unlikely to be a juvenile.

    Small as they are, the teeth are actually a little larger than teeth with similar morphology from Carmel Church.

  3. Doug says:

    That small huh? Then i would say this guys rivals a midget whale i saw at the California Academy of Sciences (a baleen whale probably no more than 12 feet long). Shame there wasn’t more of this guy preserved.

  4. Boesse says:

    Beautiful dentary! That simply looks spectacular. It does strike me as being very small. And hooray, it looks like I can finally post again.

    Doug: what was this mysticete skeleton at CAS? …fossil or modern?

  5. Doug says:

    It was a fossil. Like i said, it was probably no more than 12 feet long. I don’t have any pictures of it (i was pretty young at the time), but i do have a few seconds of video of it. I could try and upload it to my new youtube channel once i get my video capture device working again.

  6. Alton Dooley says:

    While I haven’t done the measurements yet, I think it’s about the size that would be expected for the Calvert skulls that were referred to Orycterocetus by Kellogg. Those are definitely tiny sperm whales.

  7. Dave Bohaska says:

    We have a small mandible from the same area, and a larger set from Chesapeake Beach, MD. Modern sperm whale is one of most size sexually dimorphic mammals, which might explain the size difference. Also probably multiple species in the Calvert, although at least one has enamel crowned teeth. So far, mandibles in shorter supply than skulls (and not enough of those).

  8. Alton Dooley says:

    I’ve never really been convinced that the two skulls Kellogg referred to Orycterocetus are in fact the same taxon.

    If those are different from each other, I’d say there are at least 4 sperm whale taxa in the Calvert, two with enamel and two without.

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