Worth pointing out that while Deb is IMHO right that shape cannot be ascertained from linear caliper measurements, it CAN be both measured and statistically analysed using geometric (as opposed to traditional) morphometrics - GMM - and a landmark approach based on carefully taken photographs. This is often applied to occlusal surfaces of teeth, certainly for bears and pigs thus far.
However, I don't know if this approach has yet been applied to horse teeth. Probably. If anyone does know of such work I'd be grateful for the reference. Otherwise, there's a project for someone!
Best,
David
> On 19 Jul 2014, at 08:26, "Deb Bennett" <[log in to unmask]> wrote:
>
> Jonathan, there is a large body of literature on this subject; the two
> authors to go to first are Vera Eisenmann and Ann Forsten. For a handy
> start on getting the references, look in the bibliography to Bruce
> MacFadden's book "Fossil Horses."
>
> Though they take somewhat different approaches, both Eisenmann and Forsten
> are of the opinion that if you take enough measurements on enough
> specimens, that you will then be able to tell equines apart
> "statistically". I have never felt real comfortable with this, any more
> than I feel that morphometrics per se can lead you to a grasp of the true
> relationships within any group of animals. In short, I think that the
> thing that most powerfully and accurately distinguishes one sort of animal
> from another is shape, but shape cannot be ascertained by any set of
> calipers, and cannot be specified by any manipulation, statistical,
> algebraic, or otherwise, of the set of linearities that repeated caliper
> measurements produce. In short: size cannot really proxy shape, no, not
> even when you proxy it "to a limit of infinity".
>
> Nonetheless, using size to proxy shape is the current professional norm,
> and unless you bow to the god of the caliper and the T-test, you are more
> likely to perish than be able to publish.
>
> So I'm not asking you to take my advice -- only giving it out, like just
> any other old fogey -- my advice might help you solve the problem, it
> might foster your level of insight as to what equines are all about, but
> it's not likely to help get you a job. I think that the only RELIABLE way
> to tell equine species apart is to have complete, or nearly complete,
> skulls. You can reference my "Stripes Do Not a Zebra Make" paper in
> Systematic Zoology from 1982 to get the characters by which this
> differentiation can be made.
>
> Shy of having complete skulls, complete jaw rami and/or complete
> associated rows of cheekteeth are pretty good. One can usually tell a
> horse's jaw from a mule's or donkey's on sight. If you've got teeth, you
> can look at the depth to which the ectoflexid penetrates, the separation
> of the metaconid-metastylid loops, and the shape of the linguaflexid. In
> the upper teeth you can look at the shape and relative length of the
> protocone and the degree of wrinkling exhibited by the enamel, especially
> that which rims the fossettes.
>
> Shy of skulls, jaws, or teeth, you have cannon bones -- those of asses are
> smaller and more slender, those of horses usually larger, but even if not
> larger (or longer), then certainly broader and stouter, especially the
> fore cannons. Mules will be intermediate. You can also pretty well make
> the same assessment on proximal phalanges, i.e. horsemens' term "long
> pastern bones", or indeed on any of the phalanges, again especially those
> pertaining to the forefeet.
>
> Next best after that would be just about any limb bone, the best perhaps
> being the pelvis. If very small, it's almost certainly a donkey; if very
> large, and especially if the ischium is relatively long, it's almost
> certainly a horse.
>
> Thoracic vertebrae esp. about T4-T8 of horses have longer dorsal spines
> than those of donkeys, because domestic horses have been bred to have high
> withers, whereas donkeys almost always retain the primitive condition,
> which was pretty muttony.
>
> Can't help you too much beyond this, except to say that it is very unwise
> to stick your neck out farther than a tentative assignment or "c.f." for
> anything shy of a complete or nearly complete skull. If you have a lot of
> loose unassociated teeth, you may very well be better off with Eisenmann
> and Forsten than me.
>
> For the other old fogeys reading here, by the way, I had the amusing
> experience this evening (at a wedding reception) of teaching a teenaged
> boy how to use a manual typewriter (we were to type messages of
> congratulations to the happy couple, who are also both silverhairs). This
> young man now knows what a "ribbon reverse" and a "warped platen" are.
> What will the world come to next. Cheers -- Deb Bennett
>
>
>> Hello All,
>>
>> I am working on a faunal corpus containing equid bones. For the period
>> under question there were known to be horses, donkeys, and mules at the
>> site. How can these be distinguished (esp. mule and horse)? Any tips,
>> references, or helpful advice will be greatly appreciated.
>>
>> Best,
>> Jonathan
>>
|