Horse with 17 pairs of ribs

[Dinesh Maheshwari]

Dear list members,
    My quest to find the horse with 17 pairs of ribs elicited some
unexpected data. The relevant excerpts from the emails I received
on the issue are as follows.

"The modern horses with 17 pairs are the Timor horse, the Sulu horse
and other horses of southeastern Asia.
The distribution of the above breeds is confined, as far as I know, to
Southeast and South Asia.  The 'purest' types are found in Timor and
Sulu, probably due to their isolation from intermixture with other
breeds. These breeds also have other features such as Sivalensis-like
dentition and pre-orbital depression that link them with ancient equids
in the region.
As far as I know, the Przewalski and their descendants all
have 18 pairs.
The Barb horses of Africa also sometimes have only 17 pairs of ribs.
They are somewhat different than the South/Southeast Asian horses
though, in that they have only five lumbar vertebrae rather than
six, and a convex facial profile. The S/SE Asian horses have a
slight depression near the orbit.
I don't know whether Barb horses have the large first premolars of
the upper jaw found in S/SE Asian horses."


Best regards,
Dinesh Maheshwari
Fremont, California, USA