milewski's Journal
https://theworldlink.com/news/local/2-month-old-bontebok-debuts-at-zoo/article_961cedbc-bb8a-11ec-b170-673e9365c94b.html and https://www.oregonzoo.org/node/7361/media and https://www.facebook.com/watch/?v=1029640830966480 and last few seconds of https://www.pond5.com/stock-footage/item/65434541-springbok-impala-wildebeest-and-blesbok
I have recently described the colouration of the bontebok (https://www.inaturalist.org/journal/milewski/76311-adaptive-colouration-in-the-bontebok-damaliscus-pygargus-pygargus-part-1-adults# and https://www.inaturalist.org/journal/milewski/76336-adaptive-colouration-in-the-bontebok-damaliscus-pygargus-pygargus-part-2-infants-juveniles-and-adolescents#).
However, my use of the term 'infant' is, in a way, misleading.
This is because the 'infantile' colouration in Damaliscus pygargus actually persists over a trebling of body mass after birth.
The back of neonates only reaches the height of the maternal udder:
https://www.thetablemountainfund.org.za/species-in-focus-the-bontebok/
After three months of growth, the back of 'infants' (really juveniles that have retained infantile colouration as the tips of the horns appear) reaches the height of the maternal anus:
This means that the latter are really 'juveniles dressed as infants'.
An important point about adaptive colouration in the bontebok thus emerges:
The ostensibly cryptic 'infantile' colouration, which is countershaded plain fawn (https://en.wikipedia.org/wiki/Crypsis#:~:text=Many%20animals%20have%20evolved%20so,animal%20itself%20(disruptive%20coloration), cannot actually function cryptically.
This is because
Among ruminants, the bontebok is extreme in the dichotomy between the infantile and adult patterns of colouration. These patterns are so different that the only elements in common are:
These elements are functionally trivial, and cannot outweigh the categorical difference in pattern.
The infantile colouration of the bontebok resembles that of adults of a thoroughly inconspicuous ruminant, the bohor reedbuck (https://www.inaturalist.org/taxa/42304-Redunca-redunca).
Were it the case that infants hide for several weeks, and that the infantile colouration is lost at several weeks old, then the infantile colouration of the bontebok could be interpreted as adaptive. However, such is not the case.
So, how has the evolutionary process resulted in the infantile colouration of the bontebok?
This adds to at least two other unsolved questions about the colouration of the bontebok, viz.
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I have recently scrutinised all of the thousands of photos, on the Web, of Damaliscus pygargus (https://www.inaturalist.org/taxa/42275-Damaliscus-pygargus).
The following are my findings, w.r.t. the differences in appearance between the two subspecies.
In all cases, I show the blesbok (Damaliscus pygargus philipsi) first, and the bontebok (Damaliscus pygargus pygargus) second.
Please note that sexual dimorphism is greater in the blesbok than in the bontebok.
MALE BODY FORM STOUTER IN BLESBOK
Blesbok https://es.123rf.com/photo_27663869_a-blesbok-antelope-damaliscus-pygargus-standing-in-grassland-south-africa.html
Bontebok https://www.krugerpark.co.za/africa_bontebok.html
HORNS LONGER IN BLESBOK
Female:
Blesbok https://www.dreamstime.com/royalty-free-stock-photos-blesbok-antelope-image3045098
Blesbok https://www.agefotostock.com/age/en/details-photo/blessbock-damaliscus-pygargus-phillipsi-suedafrika-afrika-gruppe-blesbok-damaliscus-pygargus-phillipsi-south-africa-group/ZON-2448458/1
Bontebok https://www.alamy.com/bontebok-female-with-young-de-hoop-nature-reserve-western-cape-south-africa-africa-damaliscus-dorcas-dorcas-image228117439.html?imageid=373F25EB-E0E9-443A-8DD5-4194A60EEA24&p=205512&pn=1&searchId=e1c83791dbb28b2649d55bb669e0fbda&searchtype=0
Male:
Blesbok https://www.agefotostock.com/age/en/details-photo/blesbok-damaliscus-pygargus-phillipsi-adult-in-open-grassland-feeding-on-dry-grass-mountain-zebra-national-park-eastern-cape-south-africa-africa/ZI6-3207749/1
Bontebok https://www.alamy.com/bontebok-damaliscus-pygargus-damaliscus-dorcas-damaliscus-dorcas-dorcas-on-grassland-south-africa-bredasdorp-de-hoop-nature-reserve-image255390786.html
MALE HORNS PALER IN BLESBOK
Blesbok https://www.agefotostock.com/age/en/details-photo/blesbok-damaliscus-pygargus-phillipsi-mountain-zebra-national-park-south-africa-africa/RHA-764-3210/1
Bontebok https://www.gettyimages.com.au/detail/photo/bontebok-damaliscus-dorcas-at-bontebok-national-royalty-free-image/523049311?phrase=bontebok&adppopup=true
TAIL:
PALE STALK LONGER IN BONTEBOK
TASSEL PALER AND LONGER IN BLESBOK
Blesbok https://www.alamy.com/blesbok-damaliscus-pygargus-phillipsi-an-antelope-endemic-to-south-africa-and-swaziland-grazing-in-grassland-image344938371.html
Blesbok https://www.gettyimages.no/detail/photo/blesbok-antelopes-in-heat-royalty-free-image/547464562?adppopup=true
Bontebok https://www.dreamstime.com/stock-image-bontebok-antelope-image14126791
BACK-OF-EAR SHEENIER IN BLESBOK
Blesbok https://www.agefotostock.com/age/en/details-photo/blesboks-damaliscus-pygargus-phillipsi-two-adults-standing-in-open-grassland-alert-mountain-zebra-national-park-eastern-cape-south-africa-africa/ZI6-3207754/1
Bontebok https://www.inaturalist.org/observations/71049460
LOWER LEGS CLEARER IN BONTEBOK
Blesbok https://upload.wikimedia.org/wikipedia/commons/3/3a/Damaliscus_pygargus_phillipsi.jpg
Bontebok https://www.alamy.com/stock-photo-bontebok-antelope-17066360.html?imageid=AFA96455-2E25-41C8-91B0-1B7B94A1EA3C&p=4877&pn=1&searchId=abde0ec3b06a08943ffb523ff66f0db0&searchtype=0
RUMP CLEARER IN BONTEBOK
Blesbok https://www.istockphoto.com/photo/beautiful-blesbok-antelope-with-a-white-face-standing-in-the-green-field-gm1455330187-490697231?phrase=pics%20of%20a%20blesbok
Bontebok https://www.inaturalist.org/observations/57714646
PALE FACE MORE EXPANSIVE IN BLESBOK
Blesbok https://www.shutterstock.com/it/image-photo/antelope-wild-blesbok-blesbuck-lying-down-2223739223
Blesbok https://www.inaturalist.org/observations/70027286
Bontebok https://stock.adobe.com/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=damaliscus&order=relevance&safe_search=1&limit=100&search_page=10&search_type=pagination&get_facets=0&asset_id=271748733
TORSO:
VENTRAL PALE MORE EXTENSIVE IN BONTEBOK
BACK MORE CONTRASTING WITH FLANKS IN BONTEBOK
Blesbok https://www.agefotostock.com/age/en/details-photo/bontebok-blesbok-damaliscus-dorcas-stands-in-african-savanna-south-africa-eastern-cape-mountain-zebra-national-park/BWI-BS420963
Bontebok https://www.gettyimages.com.au/detail/photo/bontebok-damaliscus-dorcas-endemic-species-of-royalty-free-image/139810109?phrase=bontebok&adppopup=true
BACK-OF-FORELEG MORE DISTINCT IN BLESBOK
Blesbok https://stock.adobe.com/search/images?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=0&filters%5Bcontent_type%3Atemplate%5D=0&filters%5Bcontent_type%3A3d%5D=0&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=blesbok&order=relevance&price%5B%24%5D=1&safe_search=1&limit=100&search_page=3&search_type=pagination&get_facets=0&asset_id=514194342
Bontebok https://www.gettyimages.com.au/detail/photo/bontebok-side-view-royalty-free-image/200214468-001?phrase=bontebok&adppopup=true
Bontebok https://www.gettyimages.com.au/detail/photo/bontebok-bushmans-kloof-private-game-reserve-royalty-free-image/925965224?phrase=bontebok&adppopup=true
INFANTS PALER IN BLESBOK
Blesbok https://www.shutterstock.com/it/image-photo/blesbok-mother-small-calf-leaning-against-91405400
Blesbok https://stock.adobe.com/search/images?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=0&filters%5Bcontent_type%3Atemplate%5D=0&filters%5Bcontent_type%3A3d%5D=0&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=blesbok&order=relevance&price%5B%24%5D=1&safe_search=1&limit=100&search_page=3&search_type=pagination&get_facets=0&asset_id=410239969
Bontebok https://www.inaturalist.org/photos/40826355
Bontebok https://www.dreamstime.com/royalty-free-stock-image-mother-calf-blesbok-antelope-image21744916
Bontebok https://www.mediastorehouse.com.au/ardea-wildlife-pets-environment/danita-delimont/bontebok-rare-antelope-bushmans-25400655.html
INFANTILE FACIAL MARKINGS CLEARER IN BONTEBOK
Blesbok https://www.shutterstock.com/it/image-photo/blesbuck-newborn-baby-89983321
Blesbok https://stock.adobe.com/search/images?k=blesbok&asset_id=544432933
Bontebok https://www.shutterstock.com/it/image-photo/bontebok-calf-national-park-swellendam-western-2090432353
Bontebok https://www.inaturalist.org/observations/137997739
Bontebok https://upload.wikimedia.org/wikipedia/commons/e/e4/Bontebok_%28Damaliscus_pygargus_pygargus%29_young_..._%2832834333045%29.jpg
Bontebok https://www.flickr.com/photos/berniedup/50179826247
JUVENILE FACE DARKER IN BLESBOK
Blesbok https://www.agefotostock.com/age/en/details-photo/juvenile-blesbok-damaliscus-pygargus-phillipsi-mountain-zebra-national-park-south-africa-africa/RHA-764-4222/1
Blesbok https://www.agefotostock.com/age/en/details-photo/juvenile-blesbok-damaliscus-pygargus-phillipsi-mountain-zebra-national-park-south-africa-africa/RHA-764-4226/1
Bontebok https://www.gettyimages.com.au/detail/photo/bontebok-damaliscus-dorcas-at-bontebok-national-royalty-free-image/523049313?phrase=bontebok&adppopup=true
PALE SPOT ON FOREHEAD APPEARS AT >1 YEAR IN BLESBOK, VS 4 MONTHS IN BONTEBOK
Blesbok https://www.inaturalist.org/observations/21633759
Blesbok https://www.istockphoto.com/photo/young-blesbok-gm947259792-258650817
Blesbok https://www.agefotostock.com/age/en/details-photo/blesbok-damaliscus-pygargus-phillipsi-young-walking-in-open-grassland-alert-mountain-zebra-national-park-eastern-cape-south-africa-africa/ZI6-3207756
Bontebok https://es.123rf.com/photo_10162424_bontebok-damaliscus-dorcas-at-bontebok-national-park-in-south-africa.html
Bontebok https://www.shutterstock.com/it/image-photo/bontebok-antelope-calf-national-park-south-124597081
Bontebok https://www.shutterstock.com/it/image-photo/bontebok-antelope-female-calf-national-park-124597063
DISCUSSION
I have not featured the usual distinction, viz. that of a separation between the pale rostrum and the pale patch on the forehead (https://www.dreamstime.com/stock-image-blesbok-buck-head-image29082851).
This is because it has been overrated, given the individual variation and a tendency for coalescence with age in the blesbok.
Of the distinctions I have featured above, a few are well-known, but most have been previously underplayed - or completely overlooked.
Features which seem never to have been previously mentioned in the literature are those involving
Regarding the ears and tail-tassel, the previous oversight is understandable, because a particular search-image is needed. However, regarding expansion of pale on the face, the previous oversight is surprising. This is because dozens of photos of the blesbok on the Web, particularly from zoological gardens, show the phenomenon clearly.
The distinctions between the blesbok and the bontebok at the infantile and juvenile stages deserve further scrutiny, beyond the limited photographic evidence.
This is partly because ontogenetic differences - as well as those of sexual dimorphism - are likely to be particularly revealing, taxonomically.
Given this comprehensive list of phenological clues, it remains possible that the blesbok and the bontebok are different species, not merely subspecies.
@tonyrebelo @jeremygilmore @ludwig_muller @botswanabugs @oviscanadensis_connerties @tandala @capracornelius @michalsloviak @henrydelange @ray_turnbull @bit @matthewinabinett @fdoucet @felix_riegel @jaunnemarelize @dbeadle @paradoxornithidae @geichhorn @alexiadievart @coyotehog2 @lswift @stanvrem @cheekychew @jandutoit @bobby23 @jwidness @gigilaidler @simontonge @markheystek @bluehillescape
...continued from https://www.inaturalist.org/journal/milewski/76311-adaptive-colouration-in-the-bontebok-damaliscus-pygargus-pygargus-part-1-adults#
The bontebok is well-known for its extreme colouration. However, what is not generally appreciated is how complex the facial colouration is, as it develops from birth to adulthood.
This complexity has never, as far as I know, been described, let alone explained.
At birth, the colouration of the bontebok is fairly plain (https://www.alamy.com/bontebok-damaliscus-pygargus-dorcas-three-ewes-with-their-calves-dehoop-nature-reserve-western-cape-south-africa-september-image262940011.html?imageid=37BEF09A-E8CD-4363-BA0C-D7A889A5A0DE&p=215617&pn=4&searchId=dca6a568865628209af3d56514ac1f36&searchtype=0).
This is puzzling, given that infants do not hide in this species, instead accompanying their mothers from the start.
However, the puzzle of plain colouration in infancy is eclipsed by a greater puzzle as the animal grows into the juvenile stage.
This is because the facial pattern goes through a series of changes that seem superfluous to the relatively simple conversion of the fawn-coloured rostrum of infants to the white rostrum of adults.
It is almost as if Nature has used the juvenile face of the bontebok as a canvas, on which to paint - merely for their own sake - a series of organised designs, before erasing them (https://www.shutterstock.com/it/image-photo/bontebok-antelope-calf-national-park-south-124626181 and https://www.shutterstock.com/it/image-photo/young-bontebok-waiting-cross-road-national-1012848241 and https://pixels.com/featured/bontebok-tony-camachoscience-photo-library.html).
INFANTS
At birth, the bontebok is fawn-coloured with countershading, plus
The pattern on the head may seem negligible at first glance. However, on closer examination it poses a fundamental evolutionary puzzle.
I describe this pattern as follows:
The facial pattern of infants of the bontebok is inconspicuous, because
However, what is remarkable is that this pattern is not merely a nebulous or incipient version of the adult colouration, as is the case in hippotragin bovids (https://www.inaturalist.org/journal/milewski/76424-which-ruminant-is-born-with-the-most-conspicuous-facial-pattern-of-colouration-part-1-hippotragin-and-alcelaphin-bovids#).
Instead, the pattern is different from that in adults. It is as if infants and adults are different species.
To be precise, the only parts of the head of infants that already show adult colouration are:
The following show infants close-up:
https://www.inaturalist.org/observations/63400386
https://www.inaturalist.org/observations/115686906
https://www.inaturalist.org/observations/99722303
The following show infants with their mothers:
https://www.dreamstime.com/royalty-free-stock-image-mother-calf-blesbok-antelope-image21744916
https://pixels.com/featured/bontebok-mother-and-calf-peter-chadwickscience-photo-library.html
The infantile pattern of colouration persists to the age of three months. At this stage the horn-tips have appeared, and the body mass exceeds a quarter of maternal body mass:
JUVENILES
The following series provides one of the clearest illustrations of juvenile colouration in the bontebok:
https://www.shutterstock.com/it/image-photo/bontebok-damaliscus-pygargus-pygarus-south-africa-560325085 and https://www.shutterstock.com/it/image-photo/bontebok-damaliscus-pygargus-pygarus-south-africa-560325091 and https://www.shutterstock.com/it/image-photo/bontebok-damaliscus-pygargus-pygarus-south-africa-560325112.
At the juvenile stage, the colouration on the neck, body, and legs changes directly towards that of the adult.
However, the colouration of the head goes through convoluted changes.
The first change on the head is a darkening of the rostrum (https://www.alamy.com/m2-304d-yearling-bontebok-head-image6516263.html?imageid=6FB7B5E5-32AD-4555-AD1C-BE8C66B0C857&p=1787&pn=6&searchId=d7a105eea18d32dc6155ddf3de390174&searchtype=0).
The following (https://www.shutterstock.com/it/image-photo/bontebok-antelope-calf-national-park-south-124597081 and https://www.shutterstock.com/it/image-photo/bontebok-antelope-calf-earlymorning-light-125978060 and https://www.shutterstock.com/it/image-photo/bontebok-antelope-calf-de-hoop-nature-126157526 and https://www.shutterstock.com/it/image-photo/bontebok-antelope-mother-calf-national-park-124597057 and https://www.dreamstime.com/bontebok-damaliscus-pygargus-jonge-young-image129038812) show that there is a brief stage at which the darkest part of the juvenile figure (apart from the developing tail-tassel) is a particular panel on the front of the face.
This is closely followed by a darkening of the orbits, and the appearance of a complex, pale streak from the cheek, through the temple, to the crown (third photo in https://www.inaturalist.org/observations/121214288 and https://www.shutterstock.com/it/image-photo/bontebok-damaliscus-pygargus-pygarus-south-africa-560325085 and https://animals.sandiegozoo.org/animals/bontebok).
The following shows the dark/pale differentiation on the cheek (https://www.shutterstock.com/it/image-photo/bontebok-antelope-calf-national-park-south-124626181).
The following shows the maximum extent of pale on and near the temples (https://www.shutterstock.com/it/image-photo/baby-bontebok-looking-right-mediumsized-generally-485672296).
The pale on the temples is among the last signs of the juvenile colouration to disappear (https://www.inaturalist.org/observations/137506000).
The whitish ventral surface of the mandibles remains in the juvenile stage (https://www.shutterstock.com/it/image-photo/young-playful-antelope-1327148681). The following shows the discrete pattern that arises at 0.5-1 year old, only to vanish in adulthood (https://www.dreamstime.com/wild-african-animals-bontebok-one-rarest-antelope-world-beautiful-grassland-etosha-national-park-namibia-image183764936).
The following show juveniles about 4-5 months old:
https://www.inaturalist.org/observations/10843075
https://www.dreamstime.com/stock-images-bontebok-damaliscus-dorcas-image20906614
https://www.inaturalist.org/observations/104575032
The following show juveniles 0.5-1 year old, when the dark on the rostrum is being gradually replaced by the white hairs of adulthood:
https://www.inaturalist.org/observations/16478604
The following show juveniles about one year old:
The following (https://www.inaturalist.org/observations/52622577 and https://www.alamy.com/stock-photo-i-see-you-bontebok-the-bontebok-is-a-medium-sized-generally-dark-brown-119828808.html?imageid=262BD3B2-8140-4150-8B1D-BB20F2C8C369&p=260684&pn=4&searchId=29c543d132619cf1217ce0a23a3945c6&searchtype=0 and https://www.dreamstime.com/young-bontebok-grazing-young-bontebok-grazing-cape-point-national-park-cape-town-south-africa-image245392763 and https://www.dreamstime.com/stock-photo-baby-bontebok-medium-sized-generally-dark-brown-antelope-prominent-wide-white-blaze-its-face-image77372211) show particularly clearly the tardiness of the posterior surface of the upper foreleg, above the carpal, in turning dark.
Throughout the juvenile stage, the ventral surface of the neck retains the countershading that will eventually be lost in adulthood (https://www.inaturalist.org/observations/131702545).
The following, of juveniles more than one year old (https://www.alamy.com/bontebok-female-with-young-de-hoop-nature-reserve-western-cape-south-africa-africa-damaliscus-dorcas-dorcas-image228117439.html?imageid=373F25EB-E0E9-443A-8DD5-4194A60EEA24&p=205512&pn=1&searchId=abde0ec3b06a08943ffb523ff66f0db0&searchtype=0 and https://www.alamy.com/bontebok-female-and-juvenile-de-hoop-national-park-western-cape-south-africa-damaliscus-dorcas-dorcas-image414952533.html?imageid=304942E1-F18D-4D68-AE40-F31399C02086&p=1420153&pn=4&searchId=29c543d132619cf1217ce0a23a3945c6&searchtype=0), show several aspects particularly clearly, viz.
When the horns reach three-quarters of their full length (https://www.shutterstock.com/it/image-photo/yes-cute-bontebok-mediumsized-generally-dark-484356040 and https://www.shutterstock.com/it/image-photo/baby-bontebok-497894932), the few juvenile features remaining include
ADOLESCENTS
One of the last features to form completely is the dark pelage on the posterior surface of the upper foreleg, just below the white patch on the ulna (https://www.dreamstime.com/stock-photo-bontebok-perfect-pose-medium-sized-generally-dark-brown-antelope-prominent-wide-white-blaze-its-image77512322 and https://www.inaturalist.org/observations/146638259).
As the rostrum rapidly lengthens and the facial colouration approaches completeness, a dark periphery to the pale features on the forehead and rostrum can intensify and linger (https://www.istockphoto.com/photo/bontebok-antelope-gm136712138-18853032?phrase=pics%20of%20a%20blesbok and https://www.alamy.com/stock-photo-portrait-of-an-endangered-bontebok-antelope-damaliscus-pygargus-dorcas-22757989.html?imageid=D0FE2C16-1433-4C7A-9D18-B2AC8938DBEE&p=70019&pn=1&searchId=abde0ec3b06a08943ffb523ff66f0db0&searchtype=0).
The colouration becomes complete before the horns have attained their full length (https://www.dreamstime.com/stock-image-bontebok-antelope-handsome-large-eyes-grass-mouth-image34760281). However, a trace can remain of the last juvenile feature to disappear, namely the pale vertical streak on the temples, even when the horns seem full-length.
DISCUSSION
The complexity of the changes in facial colouration can be contrasted with the simplicity of the changes on the hindquarters (https://www.alamy.com/bontebok-damaliscus-dorcas-adult-and-juvenile-in-a-flower-meadow-south-image8795878.html?imageid=BEFC3720-6ABE-438B-9767-B86189806239&p=33533&pn=11&searchId=909e0db787de943a5f89073993791964&searchtype=0 and https://www.inaturalist.org/observations/47971842).
Unlike the facial bleeze, the pygal bleeze of the bontebok starts to appear at the end of infancy (https://www.inaturalist.org/observations/10980014), and then simply and directly continues to completion within a mere three months.
The pygal bleeze is complete at about six months old (https://www.shutterstock.com/it/image-photo/young-bontebok-grazing-1349950382), when the face is still unrecognisably different from that of adults.
Almost every aspect of the ontogenetic development of colouration in the bontebok is puzzling, from the viewpoint of adaptation and evolution.
The main questions arising from this examination are as follows:
@tandala @simontonge @paradoxornithidae @tonyrebelo @jeremygilmore @oviscanadensis_connerties @davidbygott @dejong @michalsloviak @christiaan_viljoen @capracornelius @gigilaidler @maxa11an
Various ruminants have bold facial markings in both sexes, helping to make the animals adaptively conspicuous.
An example is https://www.sa-venues.com/wildlife/wildlife_roan_antelope.php.
However, in most ruminants, infants hide for a period (https://www.jstor.org/stable/3061529). This makes it adaptive for the colouration to be inconspicuous at birth.
In this Post, I examine four species of bovids with boldly-marked faces, and I illustrate the colouration in infancy, relative to that in adulthood.
These are
ORYX GAZELLA (https://www.inaturalist.org/taxa/42308-Oryx-gazella)
In this species of hippotragin bovid, adults possess a facial bleeze.
At birth, the facial pattern is not plain. However, it is so nebulous that it is certainly inconspicuous (https://upload.wikimedia.org/wikipedia/commons/0/05/Oryx_gazella_3_-_Gemsbok_cub.JPG).
As infants grow, the facial pattern, like the horns, develops precocially.
https://www.zoochat.com/community/media/gemsbok-calf-whipsnade-04-jul-2014.262375/
https://www.alamy.com/gemsbok-oryx-gazella-calf-image4734981.html
https://www.alamy.com/gemsbok-oryx-gazella-calf-image4734984.html
HIPPOTRAGUS EQUINUS (https://www.inaturalist.org/taxa/42332-Hippotragus-equinus)
This hippotragin bovid probably qualifies for a facial bleeze in adults (https://www.inaturalist.org/observations/138018015).
The relationship of infants to adults is similar to that in Oryx gazella.
However, the pattern is so precocial that an argument can be made for at least a facial flag in infants. If so, H. equinus may exemplify the presence at birth of a facial flag, in ruminants.
https://es.123rf.com/photo_27725369_roan-antelope-hippotragus-equinus-calf.html
https://www.zoochat.com/community/media/roan-antelope-calf.55666/
https://www.zoochat.com/community/media/roan-antelope-calf.145764/
https://www.inaturalist.org/observations/33354786
DAMALISCUS PYGARGUS (https://www.inaturalist.org/taxa/42275-Damaliscus-pygargus)
This species of alcelaphin bovid certainly qualifies for a facial bleeze in adults.
As in the hippotragins shown above, infants are born with a trace of the facial pattern of adults. However, the relative placement of dark/pale is puzzlingly inverted (see https://www.inaturalist.org/journal/milewski/76336-adaptive-colouration-in-the-bontebok-damaliscus-pygargus-pygargus-part-2-infants-juveniles-and-adolescents# and https://www.inaturalist.org/journal/milewski/75995-adaptive-colouration-in-the-blesbok-damaliscus-pygargus-phillipsi-part-2-infants-juveniles-and-adolescents#).
https://www.zooborns.com/zooborns/2012/04/meet-blossom-the-blesbok-calf-born-at-belfast-zoo.html
CONNOCHAETES ALBOJUBATUS (https://www.inaturalist.org/observations?taxon_id=525438)
Unlike the three species shown above, the facial colouration of Connochaetes albojubatus is ambivalent in its boldness. However, I include it here because it is the form of wildebeest with the most conspicuous facial colouration.
In the case of wildebeests, the patterns tend to be obfuscated by
However, in adults of C. albojubatus, the cheeks tend to be clearer and paler than in other forms of wildebeest, and equally sheeny. This means that C. albojubatus is the wildebeest most likely to qualify for a facial flag.
What is noteworthy is that the facial pattern is also more preocial in C. albojubatus (https://inaturalist.ca/observations/110949669) than in other wildebeests, with the possible exception of another form with a pale beard, viz. Connochaetes mearnsi.
Adults:
The facial pattern in adults of C. albojubatus is, owing to individual variation and the effects of illumination, not consistent enough to qualify for a bleeze. Its maximum expression is seen in https://www.dreamstime.com/stock-photo-young-male-antelope-wildebeest-standing-marshy-lowland-sunn-sunny-afternoon-image89889139.
This pattern - which does qualify as a facial flag - consists of
https://www.alamy.com/single-wildebeest-in-amboseli-national-park-image362840009.html
https://www.dreamstime.com/blue-wildebeest-wander-grasslands-tsavo-east-park-kenay-image208617369
https://www.dreamstime.com/wildebeest-gnu-portrait-standing-savannah-africa-image155054207
https://inaturalist.ca/observations/5784993
https://www.dreamstime.com/wildebeest-gnu-portrait-standing-savannah-africa-image155054207
https://inaturalist.ca/observations/102105372
https://www.dreamstime.com/stock-photos-three-wildebeest-run-image16846173
https://www.dreamstime.com/royalty-free-stock-photos-wildebeest-image7626258
https://zooinstitutes.com/animals/eastern-white-bearded-wildebeest-almaty-zoo-26267.html
https://inaturalist.ca/observations/19542826
Infants:
There are too few photos available to assess individual variation. However, the black rostrum tends to be fully expressed at birth.
The cheeks of infants are not as obviously pale as in most adults, and the pale beard (although precocial) is inconspicuous at birth.
However, a previously overlooked aspect is that, unlike adults, the blackish of the face extends ventral to the eyes (https://www.agefotostock.com/age/en/details-photo/wildebeest-calf-in-plains-amboseli-national-park-kenya/AAM-AAES71424). The facial insignia are thus, in a limited sense, better-developed in infants than in adults, making wildebeests unusual among ruminants.
It is noteworthy that Damaliscus pygargus, another alcelaphin, also has a distinction between infants and adults in the colouration of the orbits. The difference is that, in infants of D. pygargus, the orbits are noticeably pale, not noticeably dark (https://www.zooborns.com/zooborns/antelope/).
https://www.flickr.com/photos/sdzooglobal/9270596187
Scroll in https://movementoflife.si.edu/species/wildebeest/
Scroll in https://www.zoonewengland.org/franklin-park-zoo/our-animals/mammals/hoofed/white-bearded-wildebeest/
https://inaturalist.ca/observations/106811995
Juveniles:
The facial pattern in juveniles of C. albojubatus is as conspicuous as that in adults (https://www.dreamstime.com/stock-photo-big-wildebeest-migration-african-safari-amboseli-national-park-kenia-image84361100).
As growth proceeds, the pelage below the eye loses its black pigmentation (https://inaturalist.ca/observations/6812082).
DISCUSSION
I know of no ruminant that is born with a facial bleeze.
A facial flag at birth seems plausible in Hippotragus equinus. This would be consistent with
Since infants of H. equinus hide initially, it is unknown how the precociality of the facial pattern is adaptive. Even in adults, the adaptive value of bold facial colouration in hippotragins remains poorly understood.
What is more complex, and even more intriguing, is the ontogeny of the facial pattern in certain alcelaphins.
The facial pattern in infants of wildebeests ranges from inconspicuous in Connochaetes gnou (https://www.zooborns.com/zooborns/wildebeest/ and https://www.irishnews.com/magazine/daily/2019/08/27/news/rare-baby-wildebeest-born-at-newquay-zoo-1696156/ and scroll to fifth photo in https://africafreak.com/black-wildebeest) to conspicuous in C. albojubatus.
The remaining forms are intermediate, with Connochaetes mearnsi and Connochaetes taurinus mattosi (https://www.dreamstime.com/stock-photo-blue-wildebeest-side-view-mosi-oa-tunya-nation-park-zambia-africa-image61435936) apparently exceeding Connochaetes taurinus taurinus, C. t. cooksoni, and C. t. johnstoni.
For infants of wildebeests to have conspicuous colouration seems consistent with extreme adaptation for gregariousness in open environments, and extreme precociality at birth.
However, it remains unexplained why wildebeests vary in this respect.
It remains possible that C. mearnsi (see first comment below) exceeds C. albojubatus in the consistent boldness of the facial pattern in infants. This depends on further photographic evidence.
Given that, in adults, the facial pattern in C. mearnsi is less conspicuous than that in C. albojubatus, this might make C. mearnsi unique among ruminants, in having a facial pattern more conspicuous at birth than in adulthood.
In this context, I remind readers that infants of wildebeests also possess a pedal flag (https://www.dreamstime.com/stock-photo-blue-wildebeest-connochaetes-taurinus-young-calf-playing-rain-kruger-national-park-south-africa-image60301989), absent in adults.
The bontebok (Damaliscus pygargus pygargus) is one of the most vividly-coloured wild ungulates on Earth.
However, its colouration has not previously been described coherently, relative to a conceptual framework based on adaptation. Furthermore, previous descriptions have been limited by the lack of suitable terms.
A reminder of the difference between a bleeze and a flag:
A bleeze is a large-scale feature of colouration, so bold that it makes the whole figure conspicuous even at a distance, and even when the animal is stationary.
A flag is a relatively small, or normally hidden, feature of colouration, which becomes conspicuous with motion.
The bontebok can be described as 'pied' (https://dictionary.cambridge.org/dictionary/english/pied). However, this is unsatisfactory, because
Various wild ungulates possess bleezes. However, what makes the bontebok unusual is that
In this account, I ignore the hues on the pelage of the bontebok, and consider only the tones (white, shades of grey, and black). This is because ungulates and their carnivoran predators do not perceive hues in the same ways as humans do.
OVERALL VIEWS
https://www.inaturalist.org/observations/11251852
https://www.dreamstime.com/bontebok-damaliscus-pygargus-image129038646
https://www.dreamstime.com/bontebok-damaliscus-pygargus-image129038241
FACIAL BLEEZE
The conspicuously pale patch on the rostrum of adults of Damaliscus pygargus (https://www.inaturalist.org/taxa/42275-Damaliscus-pygargus) constitutes what is probably the clearest example of a facial bleeze, in any mammal.
In the bontebok, this patch is pure white, contesting with the dark ground-colour of the face and neck.
There is minimal variation in the facial bleeze, between the sexes, and among individuals. However, a few individuals show slight expansion at the base of the horns (https://www.alamy.com/stock-photo-blesbok-or-bontebok-damaliscus-dorcas-dorcas-syn-damaliscus-pygargus-78567725.html?imageid=967A4632-A630-4F22-84B5-7F50172963C0&p=183822&pn=2&searchId=dff47d9894fdcd82529cde91c8758091&searchtype=0).
Comparison with blesbok (https://www.inaturalist.org/journal/milewski/75748-adaptive-colouration-in-the-blesbok-damaliscus-pygargus-phillipsi-part-1-adults#):
The pale rostral patch on the face seems proportionately slightly smaller in the bontebok than in the blesbok, owing to what I perceive to be a difference in the size of the head.
Furthermore, in the bontebok the pale on the face tends not to expand with age, as it does in the blesbok (https://www.shutterstock.com/it/image-photo/blesbok-antelope-damaliscus-pygargus-standing-grass-1329980789 and https://www.inaturalist.org/journal/milewski/75871-a-previously-overlooked-expansion-of-the-bles-in-the-blesbok-signifying-full-maturity-beyond-adulthood#).
However, the facial bleeze is as well-developed in the bontebok as in the blesbok, because it seems exempt from the glandular staining seen in males of the blesbok (https://www.alamy.com/a-blesbok-antelope-damaliscus-pygargus-south-africa-image66899227.html?imageid=AA000BC4-7506-4457-96A0-B91FB81FCF46&p=70019&pn=1&searchId=a83f931787d9571cb0a25aca9f82d745&searchtype=0 and https://www.alamy.com/stock-photo-portrait-of-a-blesbok-antelope-damaliscus-pygargus-south-africa-59076858.html?imageid=9FB1F37F-B684-4FE4-A0A4-9A9AC4C55B63&p=70019&pn=1&searchId=a83f931787d9571cb0a25aca9f82d745&searchtype=0).
LATERAL BLEEZE
The lateral bleeze of the bontebok is, proportionately, one of the largest bleezes seen in any ungulate. It extends from the withers and the back to the ventral edge of the thorax and the belly. It also Includes the posterior surface of the upper foreleg, and the anterior surface of the hindleg just below the knee (https://www.inaturalist.org/observations/3985830 and https://www.inaturalist.org/observations/38720040).
The pattern is one of horizontal banding on a broad design, in which the upper and lower panels are pale, with the flanks forming a dark median panel.
However, an important qualification is that the upper panel appears pale partly owing to sheen. Its conspicuousness thus depends on illumination.
https://www.inaturalist.org/observations/113481398
https://www.inaturalist.org/observations/115575412
https://www.inaturalist.org/observations/80586175
The design of the lateral bleeze of the bontebok is such that in bright sunlight at midday, when the ventral white is inconspicuous owing to shading, the dorsal sheen is 'switched on' owing to sheen (https://www.inaturalist.org/observations/27337501 and https://www.inaturalist.org/observations/27289820).
Comparison with blesbok:
A categorical difference is that, unlike the bontebok, the blesbok lacks a lateral bleeze.
The pelage of the flanks is not necessarily any paler in the blesbok than in the bontebok. However, the differences are that, in the blesbok,
Furthermore,
PYGAL BLEEZE
The pygal bleeze of the bontebok is about as large as the facial bleeze, but located at the opposite pole of the figure (https://www.alamy.com/stock-photo-a-pair-of-bontebok-antelopes-damaliscus-pygargus-dorcas-south-africa-85437994.html?imageid=8C3973B1-D533-4CA3-B604-463AAB155B2F&p=70019&pn=1&searchId=abde0ec3b06a08943ffb523ff66f0db0&searchtype=0 and https://www.dreamstime.com/stock-photo-bontebok-antelopes-pair-damaliscus-pygargus-dorcas-south-africa-image56821286).
The pale posterior feature of the bontebok
https://www.inaturalist.org/observations/80650367
https://www.inaturalist.org/observations/57714646
https://www.inaturalist.org/observations/53977868
Comparison with blesbok:
The pygal flag of the blesbok bears the same relationship to the pygal bleeze of the bontebok as the abdominal flag of the blesbok (https://www.alamy.com/blesbok-in-savannah-south-africa-image151809725.html?imageid=3B900166-AC81-4937-96B6-1CA462655F62&p=703420&pn=10&searchId=26e0b007d6f642f3bb26a9cc6900a5cf&searchtype=0) bears to the white ventral panel of the lateral bleeze of the bontebok.
Furthermore, the pygal flag of the blesbok depends mainly on sheen effects, whereas the pygal bleeze of the bontebok depends mainly on the depigmentation of the pelage.
PEDAL FLAG
The lower legs of adults of the bontebok are largely white, making them conspicuous in locomotion.
https://www.inaturalist.org/observations/127885416
https://www.dreamstime.com/stock-photo-bontebok-antelope-running-velt-image65832109
Comparison with blesbok:
Both the bontebok and the blesbok possess a pedal flag. However, this feature is better-developed in the bontebok, in which
LACK OF AURICULAR FLAG
In the bontebok, there is a considerable sheen on the short, sparse pelage on the posterior surface of the ear pinnae. In some.views this produces a noticeably pale aspect to the back-of-ear.
However, after perusing hundreds of photos, I have not found this effect to be strong or consistent enough to qualify as an auricular flag. It is better-regarded as an incipient/residual version of the pattern in the blesbok (see below).
https://www.agefotostock.com/age/en/details-photo/bontebok-antelope/ESY-001254401/1
https://www.inaturalist.org/observations/84604329#data_quality_assessment
https://www.inaturalist.org/observations/115550547
Comparison with blesbok:
The ear pinnae seem identical in size and pigmentation in the bontebok and the blesbok.
However, perusal of hundreds of photos shows that the sheeny quality of the posterior surface is better-developed in the blesbok (https://www.agefotostock.com/age/en/details-photo/blesboks-damaliscus-pygargus-phillipsi-two-adults-standing-in-open-grassland-alert-mountain-zebra-national-park-eastern-cape-south-africa-africa/ZI6-3207754/1 and https://www.agefotostock.com/age/en/details-photo/bontebok-south-africa/FHR-88889-04144-075/1) than in the bontebok.
This, together with the relatively poorly-developed sheen on the withers and back, qualifies the blesbok, in my view, for an auricular flag (https://www.inaturalist.org/journal/milewski/75905-unlike-the-blesbok-the-bontebok-damaliscus-pygargus-pygargus-lacks-an-auricular-flag#).
The lack of an auricular flag in the bontebok is significant evolutionarily. This is because all of the postcranial pale features are better-developed in the bontebok than in the blesbok.
LACK OF CAUDAL FLAG
The tail of the bontebok is large enough to be conspicuous, particularly because the white tail-stalk contrasts with the black tail-tassel (https://www.agefotostock.com/age/en/details-photo/bontebok-antelope/ESY-008277294/1). However, in terms of colouration, the tail is subsidiary to the pygal bleeze, which is the more conspicuous feature.
Furthermore, the bontebok displays its tail only in a few social contexts (e,g. courtship, https://www.alamy.com/stock-photo-bontebok-blesbok-antelope-damaliscus-damaliscus-dorcas-bovidae-male-36820913.html?imageid=D177A04E-5BB2-42A8-8538-B839CCC540E6&p=26096&pn=5&searchId=78e3c36a9917c21e07efdd82f4c4fbc0&searchtype=0), and not in alarm or fleeing. It does not seem to wag/swish the tail except in reaction to insects.
As a result, the bontebok does not, in my view, qualify for a caudal flag.
Comparison with blesbok:
The tail of the blesbok differs from that of the bontebok in that
However, the blesbok likewise fails to qualify for a caudal flag. This is because
DISCUSSION
The colouration of adults of the bontebok is configured in such a way that the figure is conspicuous, regardless of whether
to be continued in https://www.inaturalist.org/journal/milewski/76336-adaptive-colouration-in-the-bontebok-damaliscus-pygargus-pygargus-part-2-infants-juveniles-and-adolescents#...
...continued from https://www.inaturalist.org/journal/milewski/75748-adaptive-colouration-in-the-blesbok-damaliscus-pygargus-phillipsi-part-1-adults#
The blesbok has uniform pale colouration at birth, which differs categorically from that of adults.
In juveniles of Damaliscus pygargus, the facial colouration is the inverse of that of adulthood, with the facial bleeze beginning dark, and the adjacent cheeks beginning pale (https://www.dreamstime.com/stock-photo-blesbuck-late-afternoon-field-blesbok-antelope-endemic-to-south-africa-has-distinctive-white-image77761757 and https://www.dreamstime.com/stock-photo-blesbuck-late-afternoon-field-blesbok-antelope-endemic-to-south-africa-has-distinctive-white-image77761766).
INFANTS (birth to three months old, including first appearance of horns)
The colouration of infants of the blesbok is categorically different from that of adults.
The ground-colour (including the posterior surfaces of the ear pinnae) is pale, with countershading. The tail-tassel is merely incipient.
The only distinct pattern is seen on the face, where the ground-colour of the rostrum and upper lips is crisply separated from whitish cheeks. Whitish extends on to the orbits except for the anterior side of the orbits.
https://www.zoobrno.cz/en/our-animals/animals-kept/mammals/2019-01-17-damaliscus-pygargus-phillipsi
https://www.zooborns.com/zooborns/2016/07/how-to-feed-a-baby-blesbok.html
https://www.shutterstock.com/it/image-photo/blesbuck-newborn-baby-89983321
https://www.shutterstock.com/it/image-photo/blesbok-blesbuck-calf-stays-close-members-1671765892
https://www.shutterstock.com/it/image-photo/blesbok-mother-small-calf-leaning-against-91405400
https://www.inaturalist.org/observations/37983324
https://www.zooborns.com/.a/6a010535647bf3970b016764fa98c6970b-popup
https://www.gettyimages.no/detail/photo/blesboks-royalty-free-image/74077088?adppopup=true
https://stock.adobe.com/search/images?k=blesbok&asset_id=544432933
https://www.inaturalist.org/observations/10039715
https://www.inaturalist.org/observations/87530537
https://www.inaturalist.org/observations/41711968
https://unsplash.com/photos/ODftot2S_8g
The maximum body size reached by offspring within the infantile colouration is shown in the second photo in https://www.inaturalist.org/observations/151282742.
JUVENILES
3-6 months old:
https://pixabay.com/photos/africa-animals-blesbok-herd-2643568/
https://www.shutterstock.com/it/image-photo/blesbuck-143669233
https://www.inaturalist.org/observations/122366216
https://www.dreamstime.com/stock-images-young-blesbok-side-walking-past-image32075944
Six months old (see https://journals.co.za/doi/pdf/10.10520/EJC116862 ):
https://www.inaturalist.org/observations/11088490
https://www.istockphoto.com/photo/spring-joy-gm157229462-22242556?phrase=pics%20of%20a%20blesbok
6-12 months old:
https://www.inaturalist.org/observations/66790174
ADOLESCENTS (1-2 years old, see https://journals.co.za/doi/pdf/10.10520/EJC116862)
https://www.dreamstime.com/blesbok-antelope-blesbok-southern-african-savanna-image107648073
ADULTS (>2 years old, see https://journals.co.za/doi/pdf/10.10520/EJC116862)
https://www.shutterstock.com/it/image-photo/blesbok-blesbuck-damaliscus-dorcas-phillipsi-497011045
Fully mature adults:
DIFFERENCES FROM THE BONTEBOK
I have noticed then following tentative differences, which depend on further photographic evidence for verification:
What this means is that infants, and particularly juveniles, are more conspicuous in the blesbok than in the bontebok - the inverse of the relationship between these two subspecies in adulthood.
(writing in progress)
The following photo-pair shows the two subspecies in posteriolateral view.
Both have a facial bleeze, that of the blesbok being proportionately larger owing to the difference in the relative sizes of the head.
The bontebok has an extremely well-developed pedal flag, whereas this individual of the blesbok, viewed in this perspective, lacks a pedal flag.
The pygal flag of the blesbok is replaced by a pygal bleeze in the bontebok.
In the blesbok, the abdominal and ulnar flags are separate, but in the bontebok there is a white ventral panel that subsumes both the abdominal and the ulnar pattern.
Bontebok
https://www.inaturalist.org/observations/130669553
POSTERIOLATERAL VIEW
Blesbok
https://www.inaturalist.org/observations/5141221 and https://www.inaturalist.org/observations/10924282
Blesbok
https://www.inaturalist.org/observations/31573500
Blesbok
https://www.inaturalist.org/observations/85742476
Blesbok
https://www.inaturalist.org/observations/7916986
Blesbok
https://www.inaturalist.org/observations/71536880
Adult male bontebok
https://www.inaturalist.org/observations/115575412
https://www.inaturalist.org/observations/110874507
(writing in progress)
@paradoxornithidae @jeremygilmore @henrydelange @louws @andrewdeacon @embrenhar @koosretief @douglasriverside @tonyrebelo @simontonge @michalsloviak @fionahellmann @adamwelz
I have been closely familiar with Damaliscus pygargus for 60 years.
More than half a century ago, I was already sketching both subspecies with as much precision as possible, based on the limited photographic material available at the time.
Furthermore, I have collected what is perhaps the largest dossier of hard-copy photos of the blesbok (https://dewetswild.com/2016/06/23/blesbok/) and the bontebok (https://dewetswild.com/2018/02/02/bontebok/) in the world, clipped from brochures, books, and every other pre-electronic source available.
So, it should be hard to surprise me with any aspect of the appearance of the blesbok and the bontebok.
However, it was only in the last week, when I took the trouble to scrutinise every one of the thousands of relevant photos on the Web, that several surprisingly large differences have dawned on me.
In recent Posts, I have covered the
Now, in this Post, I would like to point out that even the body-conformations of the blesbok and bontebok differ.
Based on many photos in which postures and perspectives can be standardised, I now see that the blesbok differs from the bontebok in that the blesbok has
When these two main differences are combined, we can compare adult male blesbok with adult female bontebok as follows.
https://www.inaturalist.org/observations/51830740
Dear reader, to appreciate this maximum contrast, please toggle back-and-forth between https://upload.wikimedia.org/wikipedia/commons/8/84/Blesbok%2C_Damaliscus_pygargus_phillipsi%2C_at_Krugersdorp_Game_Reserve%2C_Gauteng%2C_South_Africa_%2826872993194%29.jpg and https://www.inaturalist.org/observations/51830740
The different body-conformations give the visual impression that the bontebok is the larger-bodied of the two forms. This is mainly because, in the allometry (https://en.wikipedia.org/wiki/Allometry) of ruminants, the larger the animal, the proportionately smaller the head tends to be.
Instead, it has been stated (https://animaldiversity.org/accounts/Damaliscus_pygargus/) that it is the bontebok that is, on average, about 8 kg lighter than the blesbok.
If this is true, it makes the differences even more profound.
Both the bontebok and the blesbok are 'miniaturised' within the genus Damaliscus. However, they are miniaturised along different lines, as follows
Worth emphasising here is that the major differences in colouration between the blesbok and the bontebok, which most South African naturalists have long known, are congruent with differences in body-proportions that - until now - have been overlooked.
I might even suggest that the colouration, which is relatively superficial even if completely adaptive, has distracted our eyes from the more basic differences.
Overall, I now see that the blesbok and the bontebok are about as biologically different from each other as the tessebe (Damaliscus lunatus/superstes) is from the topi (Damaliscus topi/jimela/korrigum/tiang, https://en.wikipedia.org/wiki/Damaliscus_lunatus).
Until now, only 'lumpers' would classify topi and tsessebe as the same species, whereas only 'splitters' would classify blesbok and bontebok as different species. Instead, I suggest that we should apply the same standards to the two complexes of species/subspecies.
As a result of these realisations, I now recommend that we should classify the blesbok and the bontebok as separate (albeit interfertile) species, viz. Damaliscus phillipsi and Damaliscus pygargus.
PHOTO-COMPARISONS STANDARDISED BY POSTURE AND PERSPECTIVE
Blesbok adult male
https://www.istockphoto.com/photo/blesbok-antelope-gm497409595-41786378?phrase=pics%20of%20a%20blesbok
Blesbok adult male
https://es.123rf.com/photo_27663869_a-blesbok-antelope-damaliscus-pygargus-standing-in-grassland-south-africa.html
Bontebok adult male
https://stock.adobe.com/search/images?k=blesbock&asset_id=103184585
Blesbok adult female
http://www.safaribound.co.za/wp-content/uploads/2015/12/Blesbok.jpg
Blesbok adult female
https://www.istockphoto.com/photo/blesbok-damaliscus-pygargus-phillipsi-gm487763834-73141255?phrase=pics%20of%20a%20blesbok
Bontebok adult female
https://www.istockphoto.com/photo/bontebok-gm151545556-10145249?phrase=pics%20of%20a%20blesbok
Bontebok adult female
https://www.istockphoto.com/photo/bontebok-antelope-gm182930579-14039835?phrase=pics%20of%20a%20blesbok
Bontebok adult female
https://www.inaturalist.org/observations/78211094
