The muzzle-ring as a deep ancestral marker in deer, part 1

Deer are divided into two subfamilies: cervine deer, originating in Eurasia, and odocoileine deer, which have undergone an evolutionary radiation in the Americas (see http://www.ultimateungulate.com/artiodactyla/Capreolinae.html).

Widespread among deer is a pattern of colouration on the facial fur, which I call the muzzle-ring.

The dark next to the bare skin of the nose (rhinarium) extends down to the sides of the lips. Separating this dark from the rest of the face is a vague pale band. The combination of dark and pale bands defines the muzzle-ring.

I show many photos below but the following of the white-tailed deer (Odocoileus virginianus) is a particularly clear illustration: .https://www.welcomewildlife.com/white-tailed-deer/#prettyPhoto/5/.

The muzzle-ring can be seen, at least vestigially, in both subfamilies of deer. This indicates that it was already present in the last common ancestor, which lived as long as 15 million years ago (see https://www.nature.com/articles/s41598-017-12848-9).

However, the subfamilies differ.

In odocoileine deer the muzzle-ring is common, occurring in females and males alike, and in most of the genera. By contrast, in cervine deer the muzzle-ring occurs mainly in males, and in a minor proportion of genera: e.g. Axis (https://thejeantys.net/india-ranthambore-chital) and https://lightfieldstudios.net/109219014/stock-photo-chital-cheetal-deer-axis-axis.html), Elaphurus (https://www.alamy.com/stock-photo-a-profile-portrait-of-a-pere-davids-deer-29920714.html), Dama (https://unsplash.com/photos/GS4lhheTNzY) and Cervus (Cervus elaphus: https://www.alamy.com/red-deer-cervus-elaphus-stag-head-details-england-image345138433.html and https://www.alamy.com/stock-photo-red-deer-cervus-elaphus-stag-close-up-portrait-22707357.html and https://www.alamy.com/stock-photo-red-deer-cervus-elaphus-116460490.html).

I have mentioned in previous Posts that the odocoileine genus Mazama is odd in combining a primitive appearance with advanced genetic complexity. This is one of the few genera in its subfamily in which the muzzle-ring is absent, making Mazama even more puzzling.

The rest of this post is devoted to illustrating the muzzle-ring in the various odocoileine deer. At least a faint vestige of it occurs in most odocoileine genera. In those species with seasonal changes in colouration, the muzzle-ring tends to be clearest in the winter coat. To keep the comparisons as simple as possible I have chosen photos of only females.

In Alces alces, there is a faint trace of the muzzle-ring despite the plainness of the colouration and the extreme modification of the muzzle: https://www.dreamstime.com/stock-photo-one-big-mosse-lay-grass-resting-image83534292 and https://www.dreamstime.com/reindeer-head-closeup-forest-rangifer-tarandus-fennicus-reindeer-head-closeup-forest-rangifer-tarandus-fennicus-image143041673 and https://www.dreamstime.com/close-up-wild-female-moose-elk-close-up-wild-female-moose-elk-image105889967 and https://www.cbc.ca/news/canada/thunder-bay/identify-moose-mnrf-1.4839353.

In the white-tailed deer (Odocoileus virginianus), the following show the muzzle-ring in frontal and profile views: https://www.dreamstime.com/stock-photo-white-tail-deer-doe-close-up-image41518812 and https://www.dreamstime.com/adult-doe-forest-comes-close-photo-female-deer-gets-up-woods-image203814599 and https://www.dreamstime.com/whitetail-deer-doe-winter-sniffing-air-danger-close-up-her-head-neck-ears-nose-big-brown-eyes-details-image213574799 and https://www.dreamstime.com/close-up-shot-virginia-doe-deer-image135420057 and https://www.dreamstime.com/white-tailed-deer-doe-close-up-winter-canada-white-tailed-deer-doe-close-up-winter-canada-image165378709 and https://www.dreamstime.com/royalty-free-stock-photography-whitetail-deer-doe-image17078327 and https://www.dreamstime.com/white-tailed-deer-odocoileus-virginianus-closeup-portrait-young-doe-snow-winter-minnesota-image142363197.

Although those subspecies of O. virginianus occurring in tropical forest look more like Mazama than the typical white-tailed deer, the muzzle-ring is retained:
see sixth photo in https://www.alittleofftrack.com/manuel-antonio-national-park-a-complete-guide/ and eight photo in https://www.birdgehls.com/manuel-antonio-national-park/.

In Odocoileus hemionus hemionus, the muzzle-ring is fainter than in O. virginianus: https://www.dreamstime.com/mule-deer-female-doe-close-up-standing-grasses-shoshone-national-forest-cody-wyoming-odocoileus-hemionus-image192503942 and https://www.dreamstime.com/doe-mule-deer-picture-up-close-image102167544 and https://www.alamy.com/close-up-of-reindeer-image272808293.html.

In Rangifer tarandus, the muzzle-ring is absent because only the dark component is present: https://www.freepik.com/free-photo/vertical-closeup-shot-deer-snowy-forest-winter_13785957.them.

In Capreolus capreolus, the muzzle-ring is present despite the small size of the muzzle: https://photodune.net/item/portrait-of-roe-deer-capreolus-capreolus-in-winter/24080730 and https://www.freepik.com/premium-photo/female-roe-deer-with-fluffy-winter-coat-open-mouth_9885511.htm and https://www.dreamstime.com/elegant-roe-deer-capreolus-capreolus-doe-looking-back-standing-partially-hidden-behind-small-green-spruce-tree-glade-image180799462.

In Blastocerus dichotomus, the muzzle-ring is present: https://www.gettyimages.com.au/detail/photo/white-tailed-deer-odocoileus-virginianus-in-the-royalty-free-image/1333523388?adppopup=true and https://www.istockphoto.com/photo/female-marsh-deer-gm936497224-256202781.

In Ozotoceros bezoarticus, the muzzle-ring is faintly present in at least some individuals: https://www.flickr.com/photos/walfridotomas/5710784047 and https://www.allposters.com/-sp/Pampas-Deer-Fawn-Ozotoceros-Bezoarticus-Serra-Da-Bodoquena-Mato-Grosso-Do-Sur-Province-Posters_i2635611_.htm?sizesMoveExp=true.

In Hippocamelus bisulcus, the muzzle-ring is present: https://www.flickr.com/photos/rodchile/309003716 and https://www.istockphoto.com/photo/guemal-hippocamelus-bisulcus-in-deep-snow-on-a-mountain-side-in-winter-in-torres-del-gm947670896-258749642 and https://www.quasarex.com/patagonia/animals/huemul-deer

I have yet to find any photos of Mazama showing even a faint version of the muzzle-ring. The closest is the following of Mazama gouazoubira: https://fineartamerica.com/featured/marsh-deer-blastocerus-dichotomus-claus-meyer.html. The following is labelled Mazama but I suspect it to be a tropical form of Odocoileus virginianus: https://eol.org/media/6823432.

In Pudu puda, there is a faint vestige of the muzzle-ring: https://www.alamy.com/stock-photo-southern-pudu-pudu-puda-tiny-deer-of-patagonian-forest-chiloe-island-135111483.html and https://www.alamy.com/stock-photo-worlds-smallest-deer-pudu-26274806.html and https://www.alamy.com/southern-pudu-pudu-pudu-is-worlds-smallest-deer-9-15-kg-lives-in-rainforests-image6294897.html.

פורסם על-ידי milewski milewski, אוגוסט 28, 2021 02:56 לפנה"צ

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