How to distinguish two confusing species of sand gazelles

True gazelles, of the genus Gazella, are bewilderingly speciose in Arabia and North Africa. Each species is individually variable. Many of the species have local subspecies. Photographers tend to focus on males. As a result, identification from photos - particularly in the case of females - can be difficult even for naturalists with plenty of experience with ungulates.

In the case of two species of sand gazelles inhabiting the desert dunes, the confusion is aggravated by the indiscriminate use of similar common names derived from the Arabic. 'Rhim' refers to the Saharan Gazella leptoceros while 'rheem' refers to the Arabian Gazella marica, and the two seem to be mislabelled interchangeably on the internet even when the specimens are in zoos.

The name 'slender-horned gazelle' for G. leptoceros hardly helps because both species have long, slender, somewhat asymmetrical horns in most females.

In reality, the two can easily be told apart if you know what to look for, as follows.

All species of true gazelles have are more or less fawn with whitish ventral parts separated from the fawn by a relatively dark flank-band. All also have intricate markings on the face.

First, look at the fawn of the body, neck and legs. In G. leptoceros, this is the most uniform of any species of true gazelle, whereas in G. marica it is clearly carved into a pale upper flank-band, a pale lower-haunch, and pale legs. Another difference which I have never seen mentioned in field guides is that the feet of G. leptoceros are marked with subtle dark/pale contrasts near the hooves, whereas those of G. marica are the same plain pale as the legs.

Now look at the face. In G. leptoceros there is just the standard, inconspicuous pattern typical of gazelles, except for a small whitish patch above the nose in about half of all individuals. In G. marica, the whole face tends to be conspicuously whitened.

פורסם על-ידי milewski milewski, ספטמבר 20, 2020 12:21 לפנה"צ

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