Adaptive colouration of northwestern oribi (Ourebia montana quadriscopa), part 2: buccal semet

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...continued from https://www.inaturalist.org/journal/milewski/70081-adaptive-colouration-of-northwestern-oribi-ourebia-montana-quadriscopa-part-1#

BUCCAL SEMET

Buccal semets are any markings that serve to accentuate the chewing movements of the Jaws, particularly in ruminants.

Like flags, semets are activated by motion. However, semets tend to be smaller-scale than flags, and are so subtle that they have been overlooked by naturalists and zoologists until now.

Various ruminants possess a subtle pattern of dark/pale contrast at the junction of the 'chin' and the rest of the lower jaw. I hypothesise that this aids social monitoring within the species, particularly during rumination.

When bovids or cervids rest in small groups, vigilance depends on hearing as much as eyesight.

Cud-chewing would tend to interfere with hearing, because of the 'white noise' of grinding by the teeth.

When any individual detects cause for suspicion, it stops chewing, in order to listen up. This is potentially signalled to other members of the group by the interruption of the motion of the lower jaw.

Any distinctive pattern on the lower jaw, although conspicuous only at close range, can potentially aid this collective vigilance by emphasising the chewing movements, and thus also their sudden cessation.

The following illustrate typical situations in which a buccal semet would function, in Ourebia:
https://www.inaturalist.org/observations/17121843 and https://www.inaturalist.org/observations/39848905 and https://www.inaturalist.org/observations/39220728.

To acquire a search-image for a buccal semet in Ourebia montana, let us first examine one species of cervid, and two other spp. of bovids.

Also see https://www.inaturalist.org/journal/milewski/55532-previously-overlooked-facial-expressions-in-the-wapiti#.

Rusa unicolor:

https://twitter.com/D_Supriya/status/1270262947986767872

https://stock.adobe.com/search?k=%22rusa+unicolor%22&asset_id=170943770

https://es.123rf.com/photo_21215015_closeup-face-of-deer-muntiacus-feai-side-profile-in-the-jungle-environment.html

Taurotragus oryx:

https://stock.adobe.com/au/search?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=male+eland&order=relevance&safe_search=1&limit=100&search_page=7&search_type=pagination&get_facets=0&asset_id=196960936

https://stock.adobe.com/au/search?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=male+eland&order=relevance&safe_search=1&limit=100&search_page=2&get_facets=0&search_type=pagination&asset_id=300232095

https://stock.adobe.com/au/search?as_audience=srp&as_campaign=Freepik&get_facets=1&order=relevance&safe_search=1&search_page=0&as_content=api&k=male+eland&as_camptype=test-density-b&tduid=86f6bb255d68643c6d65a89810a8b212&as_channel=affiliate&as_campclass=redirect&as_source=arvato&asset_id=464125923

https://stock.adobe.com/au/search?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=male+eland&order=relevance&safe_search=1&limit=100&search_page=2&get_facets=0&search_type=pagination&asset_id=384537149

https://stock.adobe.com/au/search?as_audience=srp&as_campaign=Freepik&get_facets=1&order=relevance&safe_search=1&search_page=0&as_content=api&k=male+eland&as_camptype=test-density-b&tduid=86f6bb255d68643c6d65a89810a8b212&as_channel=affiliate&as_campclass=redirect&as_source=arvato&asset_id=294140010

https://www.freepik.com/premium-photo/large-male-eland-antelope_5818988.htm#query=male%20eland&position=40&from_view=keyword

https://www.freepik.com/premium-photo/large-male-eland-antelope_5818980.htm#query=male%20eland&position=38&from_view=keyword

https://stock.adobe.com/au/search?as_audience=srp&as_campaign=Freepik&get_facets=1&order=relevance&safe_search=1&search_page=0&as_content=api&k=male+eland&as_camptype=test-density-b&tduid=86f6bb255d68643c6d65a89810a8b212&as_channel=affiliate&as_campclass=redirect&as_source=arvato&asset_id=294139960

https://stock.adobe.com/au/search?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=male+eland&order=relevance&safe_search=1&limit=100&search_page=3&search_type=pagination&get_facets=0&asset_id=46484692

https://stock.adobe.com/au/search?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=male+eland&order=relevance&safe_search=1&limit=100&search_page=4&search_type=pagination&get_facets=0&asset_id=402656831

https://www.dreamstime.com/large-male-eland-antelope-large-male-eland-antelope-tragelaphus-oryx-natural-habitat-image160358444

https://www.dreamstime.com/large-male-eland-antelope-large-male-eland-antelope-tragelaphus-oryx-natural-habitat-image160358548

https://www.dreamstime.com/eland-antelope-solitario-comiendo-taurotragus-oryx-one-largest-antelopes-animals-very-difficult-to-approach-image161904009

Aepyceros melampus:

https://www.dreamstime.com/close-up-profile-portrait-impala-horns-grazing-field-image254412051

https://www.dreamstime.com/stock-photo-impala-ram-profile-image19333840

https://www.dreamstime.com/stock-photo-side-profile-male-black-faced-impala-etosha-national-park-namibia-image90694760

https://www.dreamstime.com/stock-images-male-impala-antelope-fighting-tarangire-national-park-image37475334

https://www.dreamstime.com/impala-aepyceros-melampus-males-fighting-masai-mara-park-kenya-image196305617

https://www.dreamstime.com/impala-aepyceros-melampus-males-fighting-masai-mara-park-kenya-image198642974

https://www.dreamstime.com/royalty-free-stock-images-portrait-impala-image3779909

https://www.dreamstime.com/impala-antelope-close-up-portrait-female-head-moremi-game-reserve-botswana-image157882201

Ourebia montana quadriscopa:

https://www.inaturalist.org/observations/8490559

https://www.inaturalist.org/observations/67005610 (compare this with https://stock.adobe.com/search?k=%22rusa+unicolor%22&asset_id=170943770)

Ourebia montana cottoni/masakensis:

https://www.inaturalist.org/observations/104527551

https://www.inaturalist.org/observations/100799069

Discussion:

There is a pattern, in Ourebia montana, that is shared with ruminants as diverse as Rusa, Taurotragus, and Aepyceros.

However, in O. montana the pattern is so faint, to the human eye, that nobody would have noticed it, but for a search image,

I suspect that there is an ultraviolet component to the pattern in Ourebia, which the human eye can hardly detect.

Posted on September 19, 2022 05:52 AM by milewski milewski

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