Peters' gazelle differs from Grant's gazelle in ways resembling genus Gazella

Peters' gazelle (Nanger granti petersi) occurs only in eastern Kenya, and differs from the other subspecies in several ways apart from the shape of the horns in the male.

The body mass of adult males is probably only about 50 kg (similar to that of the male impala, Aepyceros melampus), compared to 60 kg or more in nominate Nanger granti granti. Adult females seem not to have been weighed, but my guess is 35kg or less, compared with an average of 40 kg recorded for the nominate subspecies.

Peters' gazelle is the only subspecies lacking a lateral bleeze - i.e. a pattern on the flanks which is conspicuous enough in profile that it makes the figure stand out rather than blending into the environment - in any individual of either sex and any age. This is because Peters' gazelle retains only the faintest darkening on the posterior part of the flank (above the stifle-fold). This feature is extended into a fully dark flank-band in juveniles of the other subspecies (e.g. see https://www.inaturalist.org/observations/8088622) and retained with additional accentuation by some individual adult females (see https://www.inaturalist.org/observations/26410343) in populations of Nanger granti notata living in the Laikipia region of central Kenya.

All Nanger granti, of all ages and both sexes in all subspecies, have a conspicuous whitish pattern - which I call a posteriolateral bleeze - on the buttocks and spilling on to the rump. In Peters' gazelle, the extension on to the rump is minimal and divided by a fawn mid-line, thus resembling the genus Gazella rather than the rest of Nanger. Furthermore, in Peters' gazelle the white extends minimally on to the tail-stalk, leaving the tail mainly dark.

Other details: in the facial colouration, the dark rostral spot is minimal in all individuals of Peters' gazelle; and whitish wraps so narrowly on to the front of the upper hindleg that it is hardly visible in profile.

Peters' gazelle is the form of genus Nanger most closely resembling Gazella in colouration (e.g. see https://www.facebook.com/NikonIndia/posts/indian-gazelle-one-of-the-finest-posers-in-nature-throughyourlensimage-courtesy-/3607500265928157/), and can be regarded as a replacement for that genus beyond its southernmost limit on the Horn of Africa. However, Peters' gazelle remains larger than any form of Gazella. It emphasises the pygal band (i.e. the dark vertical feature between the haunch and the whitish buttock) and de-emphasises the dark flank-band to a degree unknown in Gazella. The tail is slimmer and less demonstrative in its movements than in any species of Gazella. And the malar stripe forms a dark accentuation of the eye to a degree not seen in Gazella.

פורסם על-ידי milewski milewski, יוני 13, 2021 12:02 לפנה"צ

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