gastroliths in mammals [was Re: Again: origin of bird flight]

[Oliver Wings <wings@uni-bonn.de>]

Dear list,

Ahh, finally my favorite topic again ;-)

philidor11 wrote:

> HP Marjanovic:
> Though Taylor, in the following article which is all what I have on this
> hypothesis, makes a reasonably good case IMHO for *Caudipteryx* being an
> insect-eater, like the aardwolf, which also has gastroliths.)

> You:
> A mammal with gastroliths? Really?!

Gastroliths (swallowed stones) are very common in some marine mammals
(seals, sea lions, sporadic in whales). 
Furthermore, pathological gastroliths (stones which originate as an
accumulation of minerals in the stomach - see my web site
http://go.to/gastrolith for more info) are sometimes found in the
stomachs of herbivores like goats or dromedaries.

Anyhow, the only reference for coarse sand / gravel in the aardwolf is:

Anderson, M.D., Richardson, P.R.K. & Woodall, P.F. (1992): Functional
analysis of the feeding apparatus and digestive tract anatomy of the
Aardwolf (Proteles cristatus).- J. Zool., 228, pp. 423-434.

A list of gastrolith-bearing species (including mammals) was published
recently:

Whittle, C.H. & Everhart, M.J. (2000): Apparent and implied evolutionary
trends in lithophagic vertebrates from New Mexico and elsewhere.- In:
S.G. Lucas & A.B. Heckert (Eds.): Dinosaurs of New Mexico - New Mexico
Museum of Natural History and Science Bulletin, 17, pp. 75-82.

Unfortunately, this is far from being complete. 
But I try my best to improve our knowledge about this peculiar behavior
of stone-swallowing and its results. ;-)

Cheers,
Oliver

---------------------------------------------
"MUTATIO SOLA PERPETUA EST!"

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Do you know something about gastroliths?
Please let me know!
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Oliver Wings (Dipl.-Geol.)
Institut fuer Palaeontologie
Nussallee 8
D-53115 Bonn
Germany
phone:   ++49 (0)228 734683
Fax:     ++49 (0)228 733509
E-mail:  wings@uni-bonn.de
Website: http://go.to/gastrolith