Who are the Afrotherians? - If you can know one thing about safari that most do not, it is this.
We all know about the comic book superheroes that come as a crew, a motley crew usually, with looks, strengths and powers vastly different from one another. The Afrotherians are a similar gang.
Like the X-men or Avengers, the Afrotheria have an origin story as good as any heroes; forged in times immemorial and emerging from a tumultuous, dawn-world of geologic concussions, isolation and fireballs.
If we look within a modern biology textbook we might see that the Afrotheria is a Superorder of mammals, one of only four among us placental mammals. Technical stuff, but first, who is in the team?
We have the hulking Elephant capable of a tree-blasting physicality that other mortal beings can only dream of. Then we have the underground duo of the Golden Moles and the Aardvarks, so apparently like animals elsewhere on Earth (Anteaters and Moles) but in actual fact, just designs that have converged on similar engineering. The Tenrecs became stuck in Madagascar largely without any competition. They happily filled every niche and every kind of shape imaginable with one species nearly identical to the unrelated hedgehogs. The Senghis or Elephant Shrews are magical creatures that whip along groomed pathways within bush and forest, making their portraiture a vexing challenge for any photgrapher. The Hyraxes or Dassies too are here within the Afrotherians despite the assumption by most visitors to Africa that they are some kind of marmot-like rodent. Before the Antelopes, Bovides, Giraffes and other Artiodactyls proliferated in Africa in large numbers, somewhere about 35 Millon Years ago, the Hyraxes were far more supreme, with one species as large as a Volkswagen Beetle. The hoofed animals and the success they found in Africa drove the hyraxes from most of their habitats and into their last refuges among trees and rocks. The manatees and Dugongs are also in the gang and are the most cosmopolitan of the group, having occupied waters all over the world except for Antarctic. One African pioneer even lived in Alaska and attained a massive 7.5 meters. Sadly the Stellar’s Seacow was promptly driven to extinction only a handful of years after its discovery by our own cruel species (you guessed it, we are the villains in this comic).
We’re are all taught in school of the marsupials in Australia confined to their island continent. So why didn’t the same teachers tell us about the Afrotheria? One reason is that they have only recently been discovered. It wasn’t long ago that it was assumed that the Aardvark was a Pangolin and Anteater relative. The Elephant Shrews or Senghis were put with the insectivores and the Golden Mole just had to be a Mole surely? It has only been in the past 25 years that the Afrotherians have been accepted as a very legitimate biological grouping or class. The reason for the changes in tune reflect the changing tools biologists use to study evolutionary relationships, a move from just morphology (the study of the shape, size and structure of animals) to a wider consideration of the genetic codes (fossils do not produce DNA but with living tissue from living animals scientists can work backwards, using recently sequenced Genomic data across Mammal species to work out relatedness). Before good DNA sequencing biologists had only some peculiar evidence linking the Afrotheres such as internal testicles. Hardly a solid case.
As their name suggests; the Afrotherians are very distinctly African. While you might think of the noble Lion, the stately Giraffes, the Zebras, Rhinos and Antelopes as classically African, they are actually newcomers compared to the Afrotherians. While Rhinos, Zebras, Giraffes and the rest still only looked like Shrew-like ancestors, the Aardvark was splitting from the Golden Moles both going their own subterranean way beneath Africa. This some argue, was 20 Million years before the asteroid that killed the dinosaurs 66 million years ago! 40 Million years before that the Afrotherians split from you. That’s deep time folks.
A quick review of the mammals will remind us that there are Monotremes (The Duck-billed Freak and the Echidnas), Marsupials, and Placentals. The Afrotherians as well as us and all other non-pouch or egg-laying mammals are within 4 large placental groups (sometimes its 3, scientists like to fight about this stuff). The Afrotherians are one of these, a second, the Xenartha represents the funkiest of South America’s wildlife like the Sloths, Armadillos and Anteaters. Another the Laurasiatherians, represent all those even and odd-toed Ungulates mentioned above (Whales included!) as well as the Carnivores that like to eat them. Humans and all our Primate cousins are conveniently filed as Euarchontoglires with the Rats and all the other Rodents and Rabbits. Fitting isn’t it?
See a Cladogram of the Afrotherians within Placentals below from an article in Science Direct by Mark S Springer:
The Afrotherians represent about a third of all the mammal orders on Earth and yet, as for species they only represent 80 species or .01 % of the 6400 species of mammals on the planet. This according to the IUCN Afrotherian Specialist Group, means that with only a few extinctions Africa and the planet would lose a significant amount of its biodiversity and over 100 million years of evolution. Imagine how many millions of years of evolutionary significance lies within an animal like the Dewinton’s Golden Mole which was only recently rediscovered after 80 years of being “missing”.
While you are on safari, impress the guide or your travelers with some kind words about the Afrotherians and with a sundowner you might try to transcend all the deep time between now and their amazing emergence on Island Africa. Get cosmic on this stuff because there is a lot here to get cosmic on.
James Christian
Here is some additional Info: