The three alcelaphin bovids of the Serengeti: a comparison of adaptive colouration, part 2

...continued from https://www.inaturalist.org/journal/milewski/77492-the-three-alcelaphin-bovids-of-the-serengeti-a-comparison-of-adaptive-colouration-part-1#

AURICULAR FLAGS

Anterior auricular flags refer to the anterior surface of the ear pinnae (usually viewed from in front of the figure), whereas posterior auricular flags refer to the posterior surface of the ear pinnae (usually viewed from behind the figure).

An alcelaphin elsewhere, namely Damaliscus pygargus phillipsi, possesses a posterior auricular flag.

However, the posterior surface of the ear pinnae is not conspicuous in any of the three species in the Serengeti.

In C. mearnsi, this surface is dark, except for its proximal ventral portion (https://www.google.com.au/search?q=Wildebeest+face+close-up&tbm=isch&sxsrf=APwXEdcOhGjX0ZFvTOQP1XppI2zteEjOfw:1680892266560&source=lnms&sa=X&ved=2ahUKEwj5qdDTs5j-AhWLplYBHUOiD6IQ_AUoAXoECAEQAw&biw=1013&bih=552&dpr=2.7#imgrc=Y_E3j3YCjT-uQM and https://focusedcollection.com/196865162/stock-photo-close-white-bearded-wildebeest-connochaetes.html). This is present already in infants (https://www.shutterstock.com/nb/image-photo/ngorongoro-crater-tanzania-africa-march-1-1961972416).
https://www.gettyimages.ie/detail/photo/lions-hunting-a-wildebeest-royalty-free-image/534975584?adppopup=true). This is precocial, being present already in jnfants (https://www.dreamstime.com/wildebeest-full-profile-another-background-wildebeest-full-profile-another-background-masai-image219783802).

In D. jimela, the surface in question has a dark tip, the extent of which is individually variable (https://www.youtube.com/watch?v=yW8XJcnl_eQ and https://www.dreamstime.com/two-topi-look-away-camera-masai-mara-two-topi-look-away-camera-showing-their-hind-quarters-oil-image219782970 and https://www.offset.com/photos/lion-panthera-leo-walking-close-to-topi-damaliscus-lunatus-masai-mara-1017957 and https://www.inaturalist.org/observations/144456049 and https://www.inaturalist.org/observations/128550886).

However, there is no dark/pale contrast or, as far as I know, sheen.

In A. cokii, the surface in question is plain fawn, similar to the ground-colour (https://www.inaturalist.org/observations/149133657).

Turning to the question of anterior auricular flags:

The anterior surface of the ear pinnae has whitish hairs in all three species, which is potentially conspicuous, depending on distance and illumination:

Connochaetes mearnsi (in which the ear pinna seems peculiarly narrow):

https://www.shutterstock.com/it/image-photo/wildebeest-closeup-white-background-2011280906 and https://www.shutterstock.com/it/image-photo/wild-wildebeest-east-africa-1170105076

Damaliscus jimela:

https://www.alamy.com/topi-portrait-damaliscus-lunatus-masai-mara-national-reserve-kenya-image333981016.html?imageid=5F01FDFD-6865-45F8-B5AB-18C665A44955&p=190655&pn=1&searchId=e4a80567726b2329ea71395d057e71cf&searchtype=0 and https://stock.adobe.com/search?k=%22topi+antelope%22&asset_id=64834158

Alcelaphus cokii:

https://www.superstock.com/asset/coke-hartebeest-head-portrait-alcelaphus-bucephalus-cokii-masai-mara-national/1566-1419938 and https://pbase.com/wimdegroot/image/103189097

In summary, the ear pinnae of the three species have definite colouration. However, the only species in which the ear pinnae are somewhat conspicuous is D. jimela, in which the whitish front-of-ear can, in certain illuminations and at certain distances, contrast with the dark of the face.

PEDAL FLAGS

Pedal flags are absent in adults of all three alcelaphin bovids of the Serengeti.

This is true notwithstanding the clear pattern in adults of D. jimela, in which the lower legs and carpals are differentiated from the upper legs (https://www.inaturalist.org/observations/148354403 and https://www.inaturalist.org/observations/139976038 and https://www.inaturalist.org/observations/139823541).

Damaliscus jimela lacks a pedal flag, because the lower legs

  • are not depigmented enough to be conspicuous in terms of pale vs dark (as opposed to hue), and
  • do not seem to be sheeny.

However, infants and juveniles of C. mearnsi have conspicuously pale lower legs, owing to a combination of depigmentation and sheen (https://www.alamy.com/stock-photo-wildebeest-with-a-new-born-calf-wildebeest-migration-serengeti-ecosystem-57497337.html?imageid=A9ED5718-341D-4433-BF05-DEF58289F8DC&p=50837&pn=1&searchId=63161ae63cf8885d338bf6e9703ed92e&searchtype=0 and https://www.pixoto.com/images-photography/animals/other/wildebeest-surviving-6657878905061376 and https://www.dreamstime.com/blue-wildebeest-newborn-calf-blue-wildebeest-connochaetes-taurinus-newborn-calf-ngorongoro-crater-national-park-tanzania-image161274444 and https://www.flickr.com/photos/147061930@N04/39727487574 and https://www.istockphoto.com/photo/baby-gnu-in-the-serengeti-national-park-gm463215041-32611182 and https://www.alamy.com/a-newborn-blue-wildebeest-brindled-gnu-connochaetes-taurinus-nursing-in-serengeti-national-park-tanzania-east-africa-africa-image374626149.html and https://www.dreamstime.com/blue-wildebeest-female-newborn-calf-blue-wildebeest-connochaetes-taurinus-female-newborn-calf-ngorongoro-crater-national-image161274456 and https://www.dreamstime.com/mother-baby-wildebeest-running-together-maasai-mara-savannah-image207464322 and https://www.dreamstime.com/mother-new-born-baby-wildebeest-walking-maasai-mara-savannah-mother-baby-wildebeest-walking-image208029498 and https://www.alamy.com/blue-wildebeest-connochaetes-taurinus-cow-and-days-old-calf-running-image62397886.html?imageid=9171F341-80CE-4163-9FE5-BD55FB97EAA4&p=94604&pn=1&searchId=7a9d75e9925e3ea8c217697d70b14364&searchtype=0).

CAUDAL FLAGS

All three alcelaphins in the Serengeti possess dark tail-tassels.

Furthermore, in A. cokii the tail-tassel is one of only two parts of the figure that are blackish (https://www.inaturalist.org/observations/27633264).

However, caudal flags are poorly-developed in all three species.

In C. mearnsi, the tail-tassel is large, and it is demonstrative in that it is swished during running, prancing and cavorting (https://www.alamy.com/stock-photo-wildebeest-migration-on-the-savannah-masai-mara-kenya-55910922.html?imageid=1AB44349-0B21-4A5A-967F-5A8EDD77A5F0&p=1163&pn=1&searchId=7a9d75e9925e3ea8c217697d70b14364&searchtype=0 and https://www.agefotostock.com/age/en/details-photo/wildebeest-brindled-gnu-connochaetes-taurinus-running-portrait-serengeti-national-park-tanzania/AAM-AAES111429 and https://www.superstock.com/asset/blue-wildebeest-connochaetus-taurinus-adult-running-serengeti-tanzania/4421-22277).w

The following show the relative sizes of the tail-tassels in A. cokii and C. mearnsi (https://www.inaturalist.org/observations/107450322 and https://www.inaturalist.org/observations/509208). The tail of C. mearnsi is perhaps the proportionately longest of any ruminant on Earth, reaching ground-level.

However, the tail of C. mearnsi

In D. jimela and A. cokii (https://www.shutterstock.com/it/image-photo/cokes-hartebeest-alcelaphus-buselaphus-cokii-kenyas-99398321), the tail-tassel is relatively small, and the tail is undemonstrative.

In D. jimela, the tail is held approximately horizontal by mature males in the courtship display (https://www.inaturalist.org/observations/143509509). Please also see comments in part 3.

In A. cokii, the tail is so slight that its blackish tassel

ABDOMINAL FLAGS

An alcelaphin elsewhere, namely Damaliscus pygargus phillipsi, possesses an abdominal flag.

A hint of this pattern can be seen in the following, of

However, all three species in the Serengeti lack abdominal flags.

BUCCAL SEMETS

A buccal semet may be present in adults of C. mearnsi, consisting of the contrast between the relatively dark mouth and the relatively pale beard (https://www.gettyimages.ie/detail/video/gnu-chews-its-cud-stock-video-footage/1173138747?adppopup=true).

This works because the beard extends right up to the mouth, offetting the movements of chewing.

A different buccal semet may possibly occur in juveniles.

The following further illustrate the colouration of the mouth in C. mearnsi (https://www.gettyimages.ie/detail/news-photo/dead-wildebeest-kenya-news-photo/143077326?adppopup=true and https://www.gettyimages.ie/detail/photo/crocodile-catching-blue-wildebeest-masai-mara-royalty-free-image/139813433?adppopup=true and https://www.gettyimages.ie/detail/photo/male-lion-portrait-feeding-on-wildebeest-carcass-royalty-free-image/1148455186?adppopup=true and https://www.alamy.com/stock-photo-lion-panthera-leo-hunting-lioness-biting-into-the-throat-of-a-gnu-15113558.html?imageid=BD1B5D91-66EC-4A96-BF1D-FE5A4C3300E0&p=53661&pn=4&searchId=66ec4ecdc5e720a4fd165f9002141568&searchtype=0).

A buccal semet is absent in D. jimela (https://www.inaturalist.org/observations/147820588 and https://www.inaturalist.org/observations/104585211 and https://www.inaturalist.org/observations/104818132).

However, A. cokii clearly possesses a buccal semet (https://www.shutterstock.com/it/image-photo/portrait-topi-this-subspecies-antelopes-found-1677593251 and https://www.shutterstock.com/it/image-photo/hartebeest-relaxing-grasslands-191758568 and https://www.dreamstime.com/stock-photo-cokes-hartebeest-masai-mara-kenya-aka-kongoni-standing-salt-lick-its-orange-eye-turned-to-camera-its-image83117372 and https://www.shutterstock.com/it/image-photo/cokes-hartebeest-serengeti-national-park-tanzania-1821801560 and https://depositphotos.com/3855301/stock-photo-closeup-portrait-of-hartebeest-antelope.html and https://www.dreamstime.com/coke-s-hartebeest-kongoni-antelope-native-to-kenya-tanzania-can-breed-lelwel-produce-hybrid-known-as-image243431831).

The following shows that, in A. cokii, the lower lips are the only part of the animal, other than the tail-tassel, with blackish pelage (https://www.shutterstock.com/it/image-photo/cokes-hartebeest-serengeti-national-park-tanzania-1821801560).

The following shows the typical situation in which the buccal semet is relevant (https://www.gettyimages.com.au/detail/news-photo/cokes-hartebeest-or-kongoni-bovidae-news-photo/492753751?adppopup=true).

The following footage, although belonging to a different species (Alcelaphus caama), shows the activation of its buccal semet (https://www.facebook.com/watch/?v=916918602674114 and https://www.youtube.com/watch?v=TcU2_qzOkqM.

ADDITIONAL PHOTOS OF ALCELAPHUS COKII (also see comment in part 3)

I have described the colouration of C. mearnsi and D. jimela, but not A. cokii, in previous Posts. The following photos further illustrate A. cokii.

https://www.alamy.com/topi-kenya-africa-image240730512.html?imageid=32B51789-67B4-4E73-B835-37608FE48038&p=788651&pn=1&searchId=2b231e9c97eacc75f20f7a32704237f7&searchtype=0https://es.123rf.com/photo_28728063_a-herd-of-coke-s-hartebeest-in-serengeti-.html

https://www.shutterstock.com/it/image-photo/young-hartebeest-approaches-mother-sunlit-savannah-1730346109

https://www.shutterstock.com/it/image-photo/closeup-cokes-hartebeest-scientific-name-connochaetes-1033695370

https://www.shutterstock.com/it/image-photo/closeup-cokes-hartebeest-scientific-name-connochaetes-773780392

https://www.agefotostock.com/age/en/details-photo/coke-hartebeest-alcelaphus-buselaphus-cokei-masai-mara-national-park-kenia/K77-229014

https://www.inaturalist.org/observations/121920320

https://www.inaturalist.org/observations/18343

https://www.inaturalist.org/observations/20041386

https://www.inaturalist.org/observations/135732653

https://www.inaturalist.org/observations/99045002

https://www.inaturalist.org/observations/18028393

https://www.inaturalist.org/observations/107943660

https://www.inaturalist.org/observations/7035195

DISCUSSION

The following shows that, in C. mearnsi, the darkness conferred by anti-sheen is conspicuous at distances ranging from 50 metres to half a kilometer (https://www.inaturalist.org/observations/151760045).

Alcelaphus cokii and D. jimela have some degree and extent of anti-sheen.

However, D. jimela - which is more intensely pigmented than A. cokii - does not emulate C. mearnsi in seeming dark at distance (https://stock.adobe.com/search?k=%22topi+antelope%22).

Part of the explanation for these differences is that C. mearnsi is migratory and extremely gregarious, whereas A. cokii is sedentary and only moderately gregarious.

The following compare the colouration of A. cokii with that of Eudorcas thomsoni nasalis - which possesses a lateral bleeze, making this gazelle unambivalently conspicuous.

The lateral pattern of E. t. nasalis qualifies as a bleeze, and not merely as a flag. This is because it

  • occupies a large proportion of the figure, and
  • is based on extremes of pigmentation/depigmentation, making it conspicuous under various illuminations.

The last photo in https://www.inaturalist.org/observations/50792870 shows that the lateral bleeze of E. t. nasalis is more conspicuous than any feature of A. cokii.

The moderate pigmentation of the rump, vs moderate depigmentation of the buttocks, in A. cokii cannot rival the boldness of the pattern in E. t. nasalis (https://www.inaturalist.org/observations/14423686).However, when the pale surfaces of A. cokii show sheen, its figure can rival that of E. t. nasalis in conspicuousness (https://www.inaturalist.org/observations/3597207).

All of the genera of alcelaphins represented in the Serengeti show great variation in colouration, depending on species/subspecies. In the case of Connochaetes, C. mearnsi is second only to Connochaetes gnou in overall conspicuousness, despite falling short of Connochaetes albojubatus in terms of a facial flag.

In the case of Damaliscus, D. jimela is not as conspicuous as Damaliscus pygargus, but more so than Damaliscus lunatus.

In the case of Alcelaphus, A. cokii is not as conspicuous as A. caama and Alcelaphus swaynei, but more so than Alcelaphus lelwel and Alcelaphus buselaphus.

To be continued in https://www.inaturalist.org/journal/milewski/77657-the-three-alcelaphin-bovids-of-the-serengeti-a-comparison-of-adaptive-colouration-part-3#...

For an index to my many Posts about the genus Damaliscus, please see https://www.inaturalist.org/journal/milewski/78238-an-index-to-my-posts-on-genus-damaliscus#.

Posted on 09 April, 2023 11:42 by milewski milewski

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