Reduction of the labial and mandibular vibrissae as part of extreme adaptation to anti-parasite grooming in impalas (Aepyceros), part 2

...continued from https://www.inaturalist.org/journal/milewski/90233-reduction-of-the-labial-and-mandibular-vibrissae-as-part-of-extreme-adaptation-to-anti-parasite-grooming-in-impalas-aepyceros-part-1#

DISCUSSION

It turns out that impalas are peculiar in having reduced vibrissae at the mouth and jaws.

Please compare https://www.dreamstime.com/impala-extreme-close-up-rams-face-base-lyre-shaped-horns-ear-pattern-clearly-visible-image186103431 with 2nd photo in https://animalia.bio/kob.

Nothing in the literature that could have led us to anticipate this discovery.

Of the above, particularly comparable genera, it is Odocoileus that has the longest and most obvious vibrissae. In the case of the mandibular vibrissae, the length is probably up to 10 centimeters.

At the other extreme, Tragelaphus differs less from impalas than do the other genera.

The remaining genera are intermediate. The vibrissae in question seem to be about 3-6 centimeters long, compared to the estimated 2 centimeters of impalas.

Unlike impalas, the cervid genera examined here (Odocoileus, Dama, and Axis) groom by means of the tongue (https://www.youtube.com/watch?v=FKztz7xHxkA and https://www.youtube.com/watch?v=iX6yquvGm7E and https://www.alamy.com/stock-photo-a-whitetail-deer-buck-licking-its-tail-27502925.html?imageid=34A0C1E0-C189-4C7B-9AE1-DA181BA90DC0&p=461&pn=1&searchId=bb2a56afdbfa89699f16c93e8f5304e2&searchtype=0 and https://www.shutterstock.com/video/clip-3792569-fallow-deer-cervus-dama-2-does-grooming and https://www.youtube.com/watch?v=JCIqhvscVEo and https://www.alamy.com/one-fawn-baby-deer-with-white-spots-all-over-licking-its-back-with-a-pink-tongue-on-a-black-background-image353470710.html?imageid=F679AF19-7672-4ABD-B65F-242CFFACC4F1&p=1248493&pn=1&searchId=bb2a56afdbfa89699f16c93e8f5304e2&searchtype=0 and https://www.istockphoto.com/photo/spotted-deer-gm1412756103-462066875?phrase=axis+deer+deer+close+up+macro&searchscope=image%2Cfilm).

I have yet to find information on the method of grooming in Antilope and Kobus.

However, other gazelles use the unspecialised incisiform teeth, not the tongue (https://www.shutterstock.com/video/clip-26357267-beautiful-shot-israeli-mountain-gazelle-licks-his and https://www.shutterstock.com/video/clip-26357333-beautiful-shot-israeli-mountain-gazelle-licks-his and https://www.dreamstime.com/male-springbok-licking-self-grassland-tan-brown-white-male-springbok-small-horns-seen-cleaning-licking-itself-image234306213 and https://www.dreamstime.com/grant-s-gazelle-nanger-granti-grooming-image267309277 and https://www.alamy.com/springbuck-calf-antidorcas-marsupialis-grooming-itself-a-single-young-springbuck-is-born-after-a-6-month-gestation-period-this-gazelle-like-antelo-image335481515.html and https://www.alamy.com/springbok-grooming-himself-in-the-kalagadi-transfrontier-park-south-africa-image333968143.html and https://www.freepik.com/premium-video/panning-shot-revealing-thomson-gazelle-licking-itself-ensuring-it-is-clean_326759 and https://www.shutterstock.com/image-photo/thomson-gazelle-head-turned-back-that-2169074853).

The same method is probably used by Antilope and Kobus, the teeth of which are shown in https://sketchfab.com/3d-models/blackbuck-skull-8f347ff041b24897b33a448cd3461ac6 and https://sketchfab.com/3d-models/waterbuck-skull-dc2abd4f5f5c4f4cb9f90407cfcbf916.

In summary,

• the bovids in this comparison groom by means of the teeth, whereas the cervids groom by means of the tongue;
• among the bovids, the teeth are specialised in the order Aepyceros > Tragelaphus > Antilope and Kobus;
• the differences in the lengths of the labial and mandibular vibrissae correspond approximately with the above distinctions;
• impalas seem to epitomise a syndrome in which both the dentition (in the form of a toothcomb) and the vibrissae (extremely shortened) are modified; and
• the significance of this combination of specialisations may be that facilitation of foraging (particularly on shrubs at night) has been traded off for facilitation of anti-parasite grooming.

Julkaistu maaliskuu 25, 2024 09:22 IP. käyttäjältä milewski