Variation in pigmentation within genus Nanger

There is no ungulate on Earth that can match Ovis dalli (https://www.inaturalist.org/taxa/42390-Ovis-dalli) for the variation in degree of pigmentation within a lineage.

Ovis dalli stonei:
https://www.alamy.com/stone-sheep-ram-in-the-wild-image379197178.html

Ovis dalli dalli:
https://focusedcollection.com/266524166/stock-photo-dall-sheep-ram-standing-high.html

The two photos above belong to the same species, and adult males are depicted in both cases. Furthermore, this species has the same colouration throughout the year, i. e. it lacks any winter coat as opposed to summer coat.

Yet, in one subspecies there is heavy overall pigmentation, whereas in the other subspecies there is virtually no pigmentation in the pelage.

(This nearly categorical variation in pigmentation, within a species, has never been satisfactorily explained in terms of adaptive colouration.)

The purpose of this Post is to illustrate a parallel - albeit not as extreme - example of the same trend, this time in the gazelle genus Nanger.

Within Nanger, one subspecies of Nanger granti (https://www.inaturalist.org/taxa/74724-Nanger-granti) is particularly heavily pigmented, whereas one subspecies of Nanger dama (https://www.inaturalist.org/taxa/74723-Nanger-dama) is virtually devoid of pigmentation, in some individuals, on the whole figure except for the neck.

NANGER GRANTI NOTATA

In this subspecies, the pigmentation in juveniles and adult females is heavier than in mature males. However, within both sexes there is individual variation.

Exceptionally heavily-pigmented individuals: http://www.awf.org/sites/default/files/media/gallery/wildlife/Thomson%26%23039%3Bs%20Gazelle/thom_teeku1.jpg?itok=x03p1IJ4

Other individuals showing heavy pigmentation for this genus:
https://www.inaturalist.org/observations/66930813
https://www.inaturalist.org/observations/24681299
https://www.inaturalist.org/observations/130937724
https://www.inaturalist.org/observations/37026485

NANGER DAMA RUFICOLLIS

scroll in https://www.columbuszoo.org/guide/animal.html?id=67d2b532-bd2f-67d7-bdc2-ff0000bf4b43
scroll in https://www.columbuszoo.org/guide/animal.html?id=67d2b532-bd2f-67d7-bdc2-ff0000bf4b43
scroll in https://www.columbuszoo.org/guide/animal.html?id=67d2b532-bd2f-67d7-bdc2-ff0000bf4b43
https://www.texasdivide.com/dama-gazelle
https://www.africahunting.com/media/dama-gazelle-full-mount-taxidermy.86134/
https://www.africahunting.com/media/dama-gazelle-full-mount-taxidermy.86133/
https://www.zoochat.com/community/media/wilde-plains-dama-gazelle.538003/
https://whozoo.org/mammals/Hoof/bovids/damas.htm
https://www.youtube.com/watch?v=lv1i8S-lDb0
https://www.wildlifebuyer.com/Listing/Details/12938426/11-DAMA-GAZELLE

Posted on August 26, 2022 08:09 PM by milewski