A study was released today in the journal Current Biology that will radically change how we classify the genus Canis.
Using genome-wide analysis, researchers led by Klaus-Peter Koepfl found that African golden jackals, including those that have recently been classified as African wolves (Canis lupus lupaster), are all genetically distinct from Eurasian golden jackals.
But they are also distinct enough from wolves to be considered their own species, which has been posited as Canis anthus, the African golden wolf. Previous studies had suggested that certain African golden jackals were actually a primitive form of wolf, but these studies were based upon mitochondrial DNA alone.
This study compared a relatively large sample of nuclear DNA from several related Canis species, and it found that golden jackals of Eurasia and those of Africa were not even closely related to each other. African golden jackals split from the coyote/wolf lineage some 1.3 million years ago, while Eurasian golden jackals split off about 1.8 million years ago.
This pretty much ends the question of Canis lupus lupaster, but it does create an interesting question.
In the Guardian‘s article on the study, Koepfli thinks that the reason these two species, the golden jackal of Eurasia and the African golden wolf, were considered the same species is because of parallel evolution.
I actually disagree with this assessment. If you go back and start looking at fossils of old wolf-like canids, they all start to look very jackal-like.
Indeed, as I’ve pointed out here many times, the black-backed and side-striped jackals are quite genetically divergent from the other wolf-like canids. They are more genetically distinct from the rest of Canis than the African wild dog and the dhole are, and both the dhole and African wild dog each has its own genus. (My remedy for this paraphyly in Canis is to put the dhole and African wild dog in Canis, but it also could be solved by creating a genus for the side-striped and black-backed jackals, which is what I think the move will be).
The reason why these two jackals look like both forms of golden jackal and the coyote is that all of these animals represent primitive forms of Canis. The ancestor of the large northern wolves that everyone knows was a coyote- or jackal-like canid, as was the ancestor of the African wild dog and the dhole.
“Primitive,” as I am using it here, means that an animal retains traits of the ancestor that sister taxa have lost. So in this perspective, the various jackal and coyote species still look very much like the common ancestor of all Canis. This type of dog is quite versatile, for it is big enough to defend itself from many other predators but it is small enough to subsist on rodents and carrion.
So now, genome-wide studies have done the following to canid taxonomy:
1. Found that the eastern wolf and red wolf are recent hybrids between wolves and coyotes and are not actually an ancient wolf species.
2. Found that red foxes in North America may be a distinct species from those of Eurasia and North Africa
3. Found that there are two species in what we used to call the golden jackal: the African golden wolf and the Eurasian golden jackal, which we might just drop to “Eurasian jackal” for common nomenclature.
So we’ve lost two species in the dog family and gained two.
And I would argue that we should recognize the tanuki of Japan as a disctinct species from the rest of the raccoon dog species, and I would also argue that the island fox of the Channel Islands is a subspecies of the mainland gray fox. It is far less genetically distinct from the gray fox than the domestic dog is from the wolf.
We also need to do similar studies on South Indian and Himalayan wolves, which have distinct mtDNA lineage.
I would really like to know what the genome-wide analysis would reveal on those two wolves.
I would also like to see an examination of black-backed and side-striped jackal populations, because I suspect there is some interbreeding where the ranges of the two species overlap.
Jackals have never been really interesting to scientists studying the dog family, but it is likely that the first canids that wandered the camps of our hunter-gatherer ancestors were black-backed jackals. It was their barks that alerted us to approaching leopards, and they got to lick some of our pots and eat some offal.
But they never made the same leap that wolves did. It is for this reason alone that I think one should be skeptical of hypotheses on dog origin that rely upon scavenging and the inheritances flight distances alone as the determining factor. No one has seen a spotted jackal of any species or one with floppy ears, but they are the world champions of scavenging.
Jackals just lack the charisma of the larger dog species, but I do know that if I ever get to Africa, the first species I want to see is the black-backed jackal. Then we’ll worry about the big cats.
Yep. I’m that much of a canid enthusiast!