Gray whale rib cage

From: Phil Clapham (phillip.clapham@noaa.gov)
Date: Fri Oct 12 2001 - 08:43:24 EDT


Hi:

Here's the response from my friend Jim Mead at Smithsonian:

Ok vertebral counts from:

Andrews, R. C.
1914
Monographs of the Pacific Cetacea. 1. The California gray whale
(Rhachianectes glaucus Cope).
Memoirs of the American Museum of Natural History, New Series,
1(5):227-287, pls. 19-27.

     The vertebrae of Rhachianectes, through the combination of
characters, differ widely from those of the other known genera of
baleen whales, the general resemblance being rather more toward
Megaptera than Balaenoptera or Eubalaena.

     The extremely rugose surfaces of practically all of the
bones of the skeleton is interesting. I know of no other large
Cetacean, except Physeter macrocephalus, in which this condition
is so pronounced. Fifty-six vertebrae seems to be the normal
number for Rhachianectes glaucus, the formulae of three
skeletons being as follows:

C D L Ca. Total
7 14 12 23 = 56 (R. C. A.) Am. Mus. Nat. Hist.
7 14 12 23 = 56 (R. C. A.) U. S. Nat. Mus.
7 14 14 21 = 56 (Beddard) British Mus.

     I think the question involving the ribs, which is prefaced by: "In
humans and sea lions
the ribs articulate twice, articulating with both the centrums and the
transverse processes of
the vertebrae." has to do with whether the ribs are double-headed. The
first 7 ribs are
double-headed in the gray whale, the last 7 are single-headed.

    The only author who had much to say about the ribs was Slijper:

Slijper, Everhard Johannes
1936
Die Cetaceen - Vergleichend-Anatomisch und Systematisch. Ein Beitrag
zur vergleichenden Anatomie des Blutgefa"ss-, Nerven- und
Muskelsystems, sowie des Rumpfskelettes ser Sa"ugetiere, mit Studien
u"ber die Theorie des Aussterbens und der Foetalisation.
Capita Zoologica, VI, VII:1-590, 253 figs.

    He wrote so much and in a language in which I am not fluent -

Perhaps steer them to:

Slijper, E. J.
1962
Whales.
Hutchinson and Co., London, 475 pp.

Hope this answers your questions.

Phil Clapham

> Joe wrote:
>
> Hi,
> I'd like to thank you for your quick response to my prior question.
> And your assumptions are correct that the other person who asked you
> the same question is in my group as well, I actually just found out
> today that she wrote to you too, kinda funny.
>
> For the gray whale skeleton in the Monterey Bay Aquarium, I wrote down
> C7, D 13, L 13, Ca 21. The thoracic part was a bit confusing to me
> because of the first part of the thoracic cavity which looks like it
> could be a clavicle, sternum, or a pair of ribs which would make D
> 14. I'd ask my professor but he's out of town until the project is
> due. I'll attach a picture of the thoracic cavity, hope it shows under
> this paragraph. Maybe you can figure it out. I'm assuming that the
> number of ribs--including the floating ribs-- is the number of
> Thoracic vertebrae.
>
> But I've got another quick question about the gray whale's ribs, incl.
> the floating ribs. How does it compare to rib cages of the human and
> the sea lion? How extensive is the sternum compared to that of the
> sea lion?
>
> I wrote down:
>
> In humans and sea lions the ribs articulate twice, articulating with
> both the centrums and the transverse processes of the vertebrae. In
> gray whales, the ribs are free and not connected down the middle, its
> not attached to the sternum, they are attached to the thoracic
> vertebrae. The ribs only articulate with the transverse processes of
> the thoracic vertebrae unlike humans and sea lions.
>
> "I'm pretty sure about the humans & gray whales info, but I'm just
> guessing on the sea lions--again because I can't find any in-depth
> info on skeletal anatomy other than humans. If you can verify any of
> the info I just mentioned it would be quite helpful."
>
> Thank you in advance.
>
> Joe
>
> ----- Original Message -----
> From: "Phil Clapham" <phillip.clapham@noaa.gov>
> To: "Joe" <nueno@pacbell.net>
> Cc: "Ask2, Address" <ask@whale.wheelock.edu>; "Williamson, Mike"
> <pita@whale.wheelock.edu>
> Sent: Thursday, October 11, 2001 5:28 AM
> Subject: Re: Grey whale vertebrae
>
> > Hi:
> >
> > Assume you're in the same class as the other person who just asked
> mne
> > this question! here's what I said to her...
> >
> > I'm not surprised you haven't been able to find this - this sort of
> > information is very obscure and you have to dig back into some very
> old
> > and not readily available sources that only us weird whale
> biologists
> > know about.
> >
> > Anyway, the vertebral formula for the gray whale, based on a
> skeleton in
> > the British Museum is: C 7, D 14, L 14, Ca 21. Typically, these
> vary
> > somewhat from one individual to another.
> >
> > According to an old source, "the... cervical vertebrae are quite
> > independent of each other as in the Rorquals, and they have the wide
> > lateral foramina formed by the transverse processes, which is so
> > conspicuous a feature of those vertebrae in Balaenoptera and
> Megaptera."
> > (Beddard 1900, cited in True 1904).
> >
> > Am checking with a friend at Smithsonian to see if there is any more
> on
> > this. Hope this helps!
> >
> > Phil

-- 
The Society for Marine Mammalogy will be holding its 14th Biennial
Conference from 28 November to 3 December 2001, in Vancouver, BC.  Visit
the conference Web site at www.smmconference.org for full details of
this important meeting.

Phillip J. Clapham, Ph.D. Large Whale Biology Program Protected Species Branch Northeast Fisheries Science Center 166 Water Street Woods Hole, MA 02543, U.S.A.

tel. 508 495-2316 fax 508 495-2066 email: phillip.clapham@noaa.gov



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