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Posts Tagged ‘African golden wolf’

We spend a lot of time debating about how wolves became dogs. A huge debate exists in the archaeological and paleontological literature about how one can determine whether the remains of a canid represent a wolf, a dog, or a transitional form between wolves and dogs. This debate is why the oldest dog remains are dated to around 14,000 years ago and come from the Bonn-Oberkassel site. Anything older than that, a big debate exists among experts about what can be used to define a wolf, a dog, or a transitional form.

But this debate does not exist solely in relatively recent transition between wolves and dogs. The entire evolution of Canis lupus is a hotly contested and often contradictory, depending upon which source one reads and whether one is looking a source that relies upon paleontological and morphological analysis or one that looks at the molecular evolution of the species.

It is well-accepted in European paleontology that Canis lupus evolved from Canis mosbachensis. Mark Derr paid particular attention to this evolution in his How the Dog Became the Dog. He posits that the extinction of the large hunting dog, Xenocyon lycaonoides, created an ecological niche that could be filled by the Mosbach wolf evolving into the gray wolf.

Yes, the Mosbach wolf was smaller than the modern gray wolf. Individuals from Northwestern Europe were mostly about the size of a modern Indian wolf or a “red wolf.” Indeed, the similarities between some of these mosbachensis wolves and red wolves are the best evidence for a unique red wolf species, for one can argue that red wolves are just a relict form of the Mosbach wolf that held on in Eastern North America. Of course, the genetic data do not agree with this assertion, but it is an interesting idea nonetheless.

My reading is that the Mosbach wolf gave rise to Canis lupus in Eurasia between 300,000 and 500,000 years ago. The coyote, though often posited as a primitive Canis, is actually derived from a divergent form of Canis lupus that got marooned in the American Southwest some 50,000 years ago and evolved to fit a jackal-like niche on a continent already dominated by dire wolves.

The Mosbach wolf disappeared from the fossil record around 300,000 years ago, but there is always a debate as to the possibility that it held on longer. The red wolf and Indian wolf are certainly possibilities for its continued existence today, but as we’ve looked at more wolf genomes both of those don’t come out so distinctive. Every study that I’ve seen that uses Indian wolf genomes finds that they are divergent Canis lupus, and the red wolf is a cross between wolves that are of that coyote type and relict Southeastern gray wolves from a later invasion of the continent. I do think there is pretty good historical data that some smaller wolves that we would define as coyotes lived in the Eastern states at the time of contact, particularly the small brown wolf of Pennsylvania mentioned by Shoemaker and the small “wolues” of Jamestown mentioned by John Smith. My guess is that no one really took stock of what they were killing when they killed off the wolves of Eastern states. It is very possible that coyote-like wolves were killed off in great numbers along with the big ones, and later on, coyotes from the plains came East, crossing with wolves and even relict original Eastern coyotes to form the modern Eastern coyote. The red wolf and the larger Eastern coyote are thus recreations of the Mosbach wolf that have happened in modern times.

In Europe, one potential late surviving Mosbach wolf was thought to have been found in Apulia, Italy, at the Grotta Romanelli site. Wolf remains have been found in the cave that date to between 40,000 and 69,000 years ago and they were often described as belonging to a late surviving Mosbach wolf. A recent morphological analysis revealed that these remains were of a peculiar form of Canis lupus that lived in that part of Southern Italy, and they were not of any kind of Mosbach wolf.

However, the Mosbach wolf is particularly intriguing. Occasionally, it has been posited as a direct ancestor of the domestic dog, but because we don’t have an overlap between the signs of the earliest dog domestication and the existence of Canis mosbachensis in the fossil record, one should be very careful in making such an assertion.

This same caveat should be placed when one sees Canis variabilis posited as dog ancestor. For one thing, there is no such thing as Canis variabilis. Instead, all the specimens listed as this species that come from the Zhoukoudian site in China have now been reassigned to Canis mosbachensis. This reassignment posits them as Canis mosbachensis variabilis, so whenever one encounters that “Canis variabilis” in a paper, just remember that they are discussing a particular East Asian form of the Mosbach wolf.

From my own speculative meta-analysis, it seems that the Mosbach wolf is ancestral to the entire wolf/dog/coyote species complex, which may include the African golden wolf, and the Eurasian golden jackal. A genome comparison study that included dogs, wolves, and one Israeli Eurasian golden jackal found that the divergence between the golden jackal and the dog and wolf species happened just before the anatomically modern Canis lupus replaced Canis mosbachensis in the fossil record. The Eurasian golden jackal could potentially be derived from a diminutive form of Canis mosbachensis that moved toward a more generalist scavenger form.

We also have some evidence of small Mosbach wolves in Europe that could have potentially gone in the direction of the golden jackal. This specimen was found not far from the Grotta Romanelli wolf that were found to be anatomically modern and not Mosbach wolves. It was found at the Contrada Monticelli site in Apulia. It was unusual in that it was quite a bit smaller than the Mosbach wolves found in other parts of Europe, and the authors found that Mosbach wolves were as morphologically variable as modern wolves are.

In North Africa, we also have a recent discovery of a canid that was much like the Mosbach wolf. The authors thought it was a bit different from the Eurasian form, and they decided to call this species Canis othmanii. This African wolf-like canid was found at a site in Tunisia and dates to the Middle Pleistocene, and it could potentially be the basal gray wolf that hybridized with the Ethiopian wolf to make the African golden wolf. More work needs to be done on this specimen, for it very well could wind up like Canis variabilis, a regionally distinct form of the Mosbach wolf.

The really fuzzy part about Canis mosbachensis isn’t that it is the ancestor of the gray wolf. The educated speculations I make about its relationship to the golden jackal and the golden wolf could be debated, and we need lots more data to figure out if I am right or not.

The really fuzzy part is what came before the Mosbach wolf. Most scholars think that Etruscan wolf (Canis etruscus), which makes an appearance in the fossil record around 2 million years ago, is the ancestor of the Mosbach wolf. For years, there was a debate about whether the Mosbach wolf was a chrono-subspecies of the Etruscan wolf or a chrono-subspecies of the gray wolf. All these suggestions would be technically true, simply because we could regard the Etruscan wolf-Mosbach wolf-gray wolf as a species that lasted and evolved over this time period.

However, a bit of a debate now exists as to whether the Etruscan wolf is the ancestor of the Mosbach wolf. An extensive morphological analysis of Etruscan wolf remains and those of another Canis species called Canis arnensis, which compared both to the modern black-backed jackal, the gray wolf, the golden jackal, and the golden wolf, found that our previous delineation between arnensis as being jackal-like and etruscus as being wolf-like were over-simplifications. Some characters of arnensis are much more like modern gray wolves than etruscus is, and it is possible that arnesis gave rise to the Mosbach wolf. Still, the bulk of scholarship thinks that the Etruscan wolf is the ancestor of the Mosbach wolf.

However, because the Mosbach wolf was not included in the analysis, it might be difficult to make such a conclusion. However, maybe the Etruscan wolf or something like it is the ancestor of the Ethiopian wolf. The ancestral Ethiopian wolf must have had an extensive range in Northern Africa for it to have hybridized with Canis mosbachensis, Canis othmanii, or a basal modern gray wolf to form the African golden wolf.

I have focused most of this post on the origins of gray wolves in the Old World, but the first Canis species to evolve were found in North America. Canis lepophagus first appeared in the fossil record 5 million years ago. It was very similar to a coyote or a Canis arnensis of the Old World. This is the part of the story where the molecular data has largely shaken up what we used to believe about coyotes. Lepophagus is thought to have evolved into the larger Edward’s wolf (Canis edwardii), which is sometimes called Canis priscolatrans. These animals might have been the same species or very closely related to the Etruscan wolf. The modern coyote is thought to have derived from edwardii/priscolatrans/estrucus 1 million years ago, but genome-wide comparisons put the existence of most recent common ancestor of gray wolves and coyotes at less than 51,000 years ago.

The dire wolf derived from Armbruster’s wolf (Canis armbrusteri). Armbruster’s wolf derived from Canis edwardii/priscolatrans/etruscus 1.8 million years ago. The dire wolf then evolved from that species 125,000 years ago, which means the dire wolf’s most recent common ancestor with modern wolves and the coyote may have been as far back as 2 or even 3 million years ago.

This analysis is still being worked out. The molecular data is constantly throwing wrenches into the machinery of paleontology, especially the paleontology of canids. The most successful extant canid lineage are full of parallel evolution and phenotypic plasticity, and in this way, it has become quite a challenge to sort out the evolutionary history of these species. At various times, large wolf-like forms have evolved as have smaller coyote or jackal-like forms.

The story of Canis starts with a coyote-like lepophagus, but right now, its likely niche is adopted by the modern coyote, which also very similar to it. But the molecular data suggest that the coyote evolved to adopt this similar niche from a larger Eurasian gray wolf and that it did not directly descend from lepophagus over 5 million years in only North America. Instead, it evolved into wolves that wandered into Eurasia, becoming the Mosbach wolf and then anatomically modern gray wolf. Some of these wolves wandered back into North America and became generalist scavengers in the land of the dire wolf.

Very similar stories likely are lost to us, but we must understand that the history of wolves is not just about getting bigger and developing pack-hunting behavior. That is one part of the story, but another part is about evolving to fit niches, which sometimes means evolving a smaller size and more generalist diet.

Some of my ideas here are very speculative, but I think they are nested in my reading of the available literature. Do not assume that I have the final story of how these creatures evolved, but just understand that the molecular side is so rarely considered in paleontology literature that it is almost like we’re reading evolutionary history of two different lineages.

More work must be done to formulate a synthesis between these two disciplines. Otherwise, there will be continued conflict, and the one using an older methodology and often working with much more incomplete data-set will fall by the wayside. And that is not the one using full genomes.

If we know what problems exist using morphological studies on extant and recently extinct canids, it is very likely that we’re missing important data on many extinct species, one for which there is no DNA to test.

Still, paleontology has much to tell us about the way early wolves lived. It can tell us much about how the ecosystems were and why wolves evolved in the way they did. But its methodologies often miss relationships between extant forms and miss the tendency toward parallel evolution.

I tried for about two years to watch Joe Rogan’s interview with Dan Flores, who wrote a book on coyotes that I think is quite full of misunderstandings about canid taxonomy. When Rogan questioned him about the papers that show a recent origin for the red wolf, Flores pretty much just dismissed those papers because they didn’t look at fossil.

That’s not how it works. Within canids, we know that parallel evolution is a big thing, and it is very possible that coyote-like and red wolf-like canids have evolved more than once on this continent. Indeed, a careful reading of the paleontology and molecular data strongly suggests that this is the case.

In fact, it has always been the case with these wolf-like canids. Big ones evolved from small ones, but sometimes, the big ones become small, because it is a better fit for survival.

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When I was a kid, Nature on PBS had a documentary about Simien jackals in the Ethiopian Highland. I remember being so fascinated by these jackals, particularly how they lived in extended family groups centered around a breeding pair. Even then, I marveled at how these animals had such a similar social structure to wolves, and my childish speculations made me wonder if these jackals could have told us how pack behavior in wolves first evolved.

But I grew up in an era before the internet, and I didn’t spend time looking at Simien jackals until I was in undergrad. I was at an old Borders bookstore, which don’t exist anymore, and I picked up a guide to African mammals. I perused my way to the canid section, hoping to find the section on bat-eared foxes. I had just read a book that documented the touching paternal behavior of this species, and I wanted to see if the guide mentioned this behavior. As I flipped through the pages, I came across the photo of the Simien jackal, but the caption under it said “Ethiopian wolf.”

I was somewhat confused by this new designation, so I read through entry on this new “wolf.”  The entry elucidated that some new DNA studies had found that the Simien jackal was found to be much more closely related to wolves than to other jackals in Africa, and the new name reflected this genetic discovery.

At the time, I was much more science illiterate than I am now, and I began to wonder if wolves had truly lived throughout Africa during the Pleistocene. Maybe these wolves were the source of the domestic dog, because we humans were a truly African species.

Later on, more studies came out.  Lots of papers suggested that some North African golden jackals were some kind of relict form of wolf in Africa, but most strongly suggested that there still were golden jackals in Africa. It was only 2015, that more in depth analysis of golden jackal, wolf, and coyote DNA revealed that all golden jackals in Africa were actually derived from a gray wolf-like ancestor. The current move it to call these animals African wolves or golden wolves, but a huge debate exists on what the exact scientific name should be: Canis lupus lupaster? Canis lupaster? Canis anthus?

I remain agnostic on what the exact scientific name for the golden wolf should be. I need more evidence, more data, before I’m going to latch  onto something. All of these problems are greatly complicated by the discovery that coyotes and gray wolves are much more closely related to each other than we thought, and the proposed million-year split between the two species was often used to gauge when the rest of the genus diverged.  These animals might all be much more closely related to each other than we imagined. 

But an even more surprising discovery just came out.  A recent genome comparison study revealed that hybridization was a major part of the evolution of wolf-like canids, but it also revealed that the golden wolf was itself a hybrid between Ethiopian wolf and the gray wolf. The authors did not estimate when this hybridization happened, but it clearly did.

This discovery points to this possible story about the Ethiopian wolf. Ethiopian wolves and gray wolves are not in any way sympatric. When the Ethiopian wolf was thought to be the only wolf in Africa, it was marveled at how a wolf managed to hold on in Africa, holding onto the last remaining cold parts of East Africa in the Ethiopian Highlands.

But if the golden wolf is really a hybrid between the gray wolf and the Ethiopian wolf, the Ethiopian wolf must have had a wider range. I bet it was even more generalist in its predation habits to have had such a wide range than the current rodent-filled diet of its surviving population. 

And then at some point, gray wolves began to wander down into Africa. These were probably primitive forms of the species, perhaps explaining why Himalayan wolves, a supposed basal form of gray wolf, share an x-chromosome with the golden wolf.

These gray wolves swamped the Ethiopian wolf range in North and East Africa, mating with the Ethiopian wolf.  This African gray wolf evolved to become smaller and more generalist, much like a jackal, but in the main, it retained a hybrid genome that is 72 percent gray wolf and 28 percent Ethiopian wolf.

For whatever reason, the gray wolf and the hybrid golden wolf never spread into the Ethiopian Highlands, where the Ethiopian wolf remained as relatively pure species.  These Ethiopian Highlands wolves had adapted to a rodent-rich diet in some of the harshest terrain in Africa, and there, they live on a relics from a time that has since passed.

They are like the last woolly mammoths of Wrangel and St. Paul Islands. The woolly mammoth of North America and Eurasia went extinct 10,000, but the ones on these two islands held on for much longer. The one on St. Paul went extinct 5,600 years ago, while the Wrangel Island population went extinct around 4,000 years ago. The St. Paul population went extinct as the lake on the island failed to provide them enough water, while the Wrangel population suffered a damaging blow when a deleterious mutation, which caused the mammoths to develop coats much like “satin” rabbits in which the coat grew shiny but less dense and useful for protection against the element, spread throughout the very inbred population.

By the time those mammoths went extinct, human civilizations were already well-advanced. We were already moving well into the agrarian epoch of Mesopotamia and Egypt, and we ceasing to be creatures of nature and becoming what we think we now are.

If the mammoths of Wrangel had never developed that deleterious mutation, we might be able to see them today, just as we can with the Ethiopian wolf.

Ethiopia today promotes the Ethiopian wolf as a major attraction in ecotourism. The country is doing all it can to preserve the species, and it very well be saved, so long as diseases from domestic dogs are held at bay and inbreeding issues don’t result the gene pool becoming swamped with a deleterious mutation or just general inbreeding depression.

No Ethiopian wolf will ever be on display at a Western zoo. You have to go to Ethiopia to see one. They hold onto this precious relic and treasure it as a vital natural resource and national treasure.

And that is how an endangered species should be treated. 

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golden wolf vs. black backed jackal

Not the best photo, but this is golden wolf on the left and a black-backed jackal on the right. I screen-captured this image from this documentary, which was made before the big golden jackal revision that happened a few years ago.

There is still a big debate on how classify the creature formerly known as the African golden jackal. It is clearly closer to gray wolves and coyote than to the Eurasian golden jackal, but the exact closeness requires further research.

The black-backed jackal on the right is a much older species. It has been known from the fossil record in Africa for over two million years, and the wolf-coyote-golden wolf lineage last shared a common ancestor with it around 4.5 million years ago.

Depending upon when we finally determine when the golden wolf diverged from the modern gray wolf, it may have evolved from larger ancient gray wolves that adapted to fit the generalist jackal-like niche, or it may have evolved from a African population of Canis mosbachensis.

The black-backed jackal is derived from the earliest wolf-like canids to have entered the Old World from North America. Those early wolves were all smaller and jackal-like, and its appearance and adaptations are of the primitive type.

So here we have two species that look like they might just be color phases of the same species but actually are divided by millions of years of evolution. One is a truly primitive member of its lineage. So primitive and basal that its now classified in a different genus (Lupullela). The other came from a more derived source that evolved parallel characteristics with the primitive one.

Parallel evolution is a hell of a thing, especially when it comes to canids. So much of this parallel evolution has been missed in paleontology and in the conventional methods of taxonomy that use only morphology. Not recognizing the parallel evolution issues is why we didn’t notice that coyotes and gray wolves were much more closely related than we ever could have imagined. It’s also why we thought bush dog belonged with the dhole and African wild dog, just because their teeth are so similar, and it is also why an affinity has been suggested between crab-eating foxes and raccoon dogs, even though they are in entirely different lineages. It is also why there was a suggestion that red wolves represent an ancient lineage of North American wolves, when they are now probably hybrids between coyotes and gray wolves.

Parallel evolution messes up a lot of things. Our eyes and our measuring instruments can fail us.

But the correction of these failures reveals a much more mysterious world.

That’s the inherent beauty of science. Each correction is a revelation.

 

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African golden wolf (Canis anthus).

African golden wolf (Canis anthus).

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!

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