Sperm whales of the Harvard Museum of Natural History
June 17, 2012
Check this baby out:
I know, I know what you’re thinking. “Enough with the vulgar overexposed skull of this beast, Taylor”, you cry: “Show us its zygapophyses!”
But of course.
This is from the anterior part of the tail, in right lateral view: the vertebrae that you see here are the third to seventh of those that carry chevrons.
The hot news here is of course that sperm whales go to all the bother of developing zygapophyses, right up at the top of their neural arches, down in a region of the body where they don’t come close to articulating and are of no conceivable use.
Anyone know why? Care to hazard a guess?
For previous adventures in the Harvard Museum of Natural History, see here (monotremes) and here (bird eggs).
Sauropod Vertebra Picture of the Week 
June 18, 2012 at 1:13 am
Because ancestors?
June 18, 2012 at 6:20 am
Zygapophyses? Where? Aren’t the dorsal structures neural spines and the lateral ones transverse processes, or am I being too dino-centric?
June 18, 2012 at 7:51 am
Look near the top of the neural spines, Micky – there are paired processes.
June 18, 2012 at 7:51 am
*Mickey; apologies for the misspelling.
June 18, 2012 at 12:23 pm
Christopher suggested:
Everything has ancestors; not everything has pointless non-articulating zygapophyses at the tops of its caudal neural spines.
June 18, 2012 at 1:57 pm
Zygapophyses aside, I can’t get past all the (fake) cartilage in that whale’s tail.
June 18, 2012 at 11:24 pm
Ah, I see. I was assuming those were just anteriorly divided neural spines like in some theropods. Dino-centric…
June 21, 2012 at 8:59 am
Non-articulating zygapophyses are seen in various cetaceans; I can recall reading that they play a role in providing attachment sites for interspinous ligaments (in which case, this is a novel co-option) but I don’t think there’s any work on their role or function. I’ll ask Emily Buchholtz.
June 21, 2012 at 9:47 am
Ok, John Hutchinson has brought my attention to Long et al. (1997). It’s on dolphins – not sperm whales – but describes how non-articulating zygapophyses play a role in ligament attachment and overall vertebral stiffness.
June 22, 2012 at 7:02 am
Question. You say the photo is of the third to the seventh vertebrae that carry chevrons. The chevron is located more or less between centra: which one is counted as “carrying” it: th one above and to the front, or the one above and to the back.
And– this is a problem I have every time I try to describe a whale skeleton– does the “caudal” series start with the first chevron-carrying vertebra?
June 23, 2012 at 7:40 am
Interesting, Darren. So I was analogously right, just not homologously right. ;)