Lena, your difficulties with distinguishing deciduous equine teeth will be
cleared up when you get the opportunity to examine some complete
dentitions of recent equines that died between foalhood and 6 years.
Particularly seek out those that are 3-4 years old, because it is at this
time that the premolar teeth shed.

You will notice several things. First, that the height of the reserve
crown of a deciduous premolar, even in a yearling where it will be at its
highest, is never all that high. The mandible of a yearling horse or
donkey isn't nearly as deep as it will be by the time the animal is mature
at six years of age.

Second, that by the time the tooth is ready to be shed, it will have worn
down almost to the roots. Thus when you find isolated deciduous premolar
teeth of horses, and the tooth has as little remaining reserve crown
height as those you picture, chances are high that the tooth was "spat"
during life. Often the inferior teeth will be split in half through the
metaconid/metastylid area as well, as the tooth is narrow and weak in this
"waist".

Third, that the occlusal enamel pattern of the tooth is "more advanced"
than that which will develop in the permanent dentition of the same
animal. In the case of the genus Equus, this means that the
antero-posteriorly oriented lines of enamel that bracket the lingual and
buccal edges of the crown are straighter (less bowed) than they would be
in the permanent premolars of the same animal; that the
metaconid/metastylid loops are longer and more flattened; and that the
reentrant formed by the entoflexid, which frequently would penetrate the
"neck" leading up to the metaconid/metastylid in the permanent tooth, is
shallower, leaving the "neck" long and undivided. The degree of
crenellation in the enamel bands generally will also be greater.

Size, as you should know, is no guide at all to the specific identity of
equines. You can have biggish donkeys and quite small horses, and,
particularly in a Roman context, you can have mules too.

Despite all the morphometrics that have been done in my lifetime on
equines, I generally don't believe a word of it. I don't think you can
identify any animal, even when there are large (>50) sample sizes, by
measuring and/or computing statistics. It is, rather, shape that
identifies -- and there is no metrical or mensural way that is adequate to
specify shape. Your eyes and brain work fine for this purpose, however.

You do have to have enough grist for that mill, though. I think that in
order to identify any horse from teeth, you have to have, at minimum, a
whole quarter-dentition, i.e. I1-M3 from one jaw quarter. Even better
would be a half-dentition, superior and associated inferior. Best of all
would be the whole skull, so that you can consider diagnostic features
such as the configuration of the mastoid region, the basiocciput, and the
facial profile. The only responsible thing to do with the tooth you
present, in my opinion, is to identify it as "Equus sp."

Deb Bennett, Ph.D., Director
Equine Studies Institute of California
& Zooarchaeologist, Vindolanda


> Dear all,
>
> Is there a good guide to identifying decidious equine teeth? I looked at
> Cluny Johnstone's thesis, but she only discusses the permanent dentitions.
> I have a very small and narrow equine cheek tooth (30.3x11.3mm) from a
> Late Roman rural settlement (UK). The tooth seems juvenile to me. The
> enamel folds are slightly different from the adult horse mandible I have
> in the reference collection, and they don't follow the illustrated adult
> donkey tooth either.
>
> I've uploaded three pictures if anyone wants to attempt an identification.
>
> http://i893.photobucket.com/albums/ac137/ossamentaDW/Benbilder/Foal-donkeytooth1.jpg
> http://i893.photobucket.com/albums/ac137/ossamentaDW/Benbilder/Foal-donkeytooth2.jpg
> http://i893.photobucket.com/albums/ac137/ossamentaDW/Benbilder/Foal-donkeytooth3.jpg
>
> /Lena
>
>
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