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Posts Tagged ‘Sardinian dhole’

xenocyon and cynotherium

Depiction of Xenocyon lycaonoides (in the back) with Cynotherium sardous (in the front).

The “hunting dogs” are sister lineage to the true wolves. They were once widespread across Eurasia, Africa, and into North America. Today, the lineage is survived by two species, the dhole (Cuon alpinus) and the African wild dog or painted dog (Lycaon pictus).

But during the Pleistocene, a third species, much larger than two extant species, was ubiquitous. This species, called Xenocyon lycaonoides, was found all over Africa and all over Eurasia.  It ranged into North America, where its remains have been described as Xenocyon texanus.

It was long accepted in paleontology that the dhole and African wild dog derived from Xenocyon lycaonoides, but new evidence that shows the African wild dog deriving from a Pliocene African species called Lycaon sekowei casts that idea into doubt. Further, because the dhole and African wild dog are so closely related to each other, it is doubtful that either derives from Xenocyon.

My take, based upon simple chronology and the genomic analysis of living species, is that Xenocyon and its offshoots were a sister lineage to that which leads to the dhole and African wild dog.

The best way to think of Xenocyon lycaonoides is that it was the gray wolf before there was a gray wolf. It was a pack-hunting canid that was able to expand its range over a wide range. It was roughly the size of a large northern gray wolf, and it would have been a formidable predator of large game.

On islands, though, Xenocyon evolution went a bit weird. On Java, two descendants of Xenocyon lycaonoides evolved. One was Merriam’s dog (Megacyon merriami). It was even larger than the mainland form, but over time, it was replaced by a smaller form that averaged 22 kg (48.5 pounds) called the Trinil dog (Mececyon trinilensis). A new analysis of these Pleistocene canids places both in the genus Xenocyon (which fits a cladistic classification model) and shows that the smaller Trinil dog derived from the larger Merriam’s dog.  Increased competition from tigers and other large predators forced the larger Merriam’s dog to target smaller prey, and over time, they became smaller.

Anothe even more extreme insular form of Xenocyon evolved on the Pleistocene island of Corsica-Sardinia. This island is now two islands in the Mediterranean, but during the Pleistocene, they were connected to each other. On that Pleistocene island, Xenocyon lycaonoides became isolated on an island that was full of small prey, especially a species endemic pika.  This Corsica-Sardinian canid became a specialist in hunting burrowing prey.  It had the ability to thrust its head out laterally better than any living canid, which would have given it an advantage in catching quick-moving prey that would take refuge in burrow.

This species is called the Sardinian dhole (Cynotherium sardous), but it is not directly related to the modern dhole. It was the size of a golden jackal or a small coyote, and it went extinct after humans colonized Corsica-Sardinia at the very end of the Pleistocene. It was the last of the Xenocyon derivatives to go extinct.

The Mosbach wolf (Canis mosbachensis) was a contemporary of the larger Xenocyon lycaonoides.  It was smaller canid that varied in size from an Eastern coyote to an Indian wolf.  It eventually would evolve into the larger gray wolf, which would have a similar evolutionary trajectory to the Xenocyon. It would spread over much of the world. Many regional forms would evolve.

Domestication, of course, would give the gray wolf lots of opportunities for weirdness to come about. Yes, as weird as the so-called Sardinian dhole was, it was never as bizarrely put together as some of our domestic dog breeds.

These extinct “wolves in parallel” do tell us a lot about how a large canid can radiate across the a broad swathe of the planet and adapt to regional conditions and thrive.

 

 

 

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The endangered African wild or "painted wolf" is a descendant of the larger Xenocyon lycanoides-- the so-called "African wolf."

Xenocyon lycaonoides.

The way the Greek rolls of the tongue suggests something like a Spartan general who led his phalanxes against the Persians.

It was actually a large  canid that lived between 1. 8 million and 126,000 thousand years ago. Although its name suggests a totally African range, it was also found in Eurasia.

It was larger than the typical modern wolf, and it was probably a major predator of  all sorts of wildlife. It is even suggested that this hulking wolfish creature preyed upon early man.

It was not a true wolf as we would know it today. It came from a different line of large wild dogs.

Its most likely descendant is the African wild dog or “painted wolf” (Lycaon pictus). However, Xenocyon was a much more robust animal than these multicolored carnivores.

Xenocyon was a very successful species from which several different forms descended. The so-called Sardinian dhole, which lived on the island that became Sardinia and Corsica, was probably descended from Xenocyon. It is often suggested that the Sardinian dhole (Cynotherium sardous) was nothing more than a dwarf insular form of Xenocyon.  Two extinct Javanese dogs may have also been descendant of Xenocyon.

Current research of the modern dhole’s molecular evolution suggests that it did not descend from Xenocyon. It is an early offshoot of the line that gave us the genus Canis. It’s more closely related to wolves, jackals, and coyotes than the African wild dog, which it superficially resembles.

There is a move in some academic circles to move Xenocyon and its variants into the genus Lycaon.

Of course, we could put all of them in the genus Xenocyon, but it would make more sense to put them in the same genus as the living species.

After all, it is now accepted that the African wild dog is the only living descendant of Xenocyon, and it would make sense that we would move all of these related dogs into the same genus.

I am trying to imagine what Xenocyon may have looked like.  A piece of me sees it as mottled in different colors with rounded ears, as is the case of the African wild dog.

But another part of me sees it as a more robust animal.

Maybe dire wolf crossed with African wild dog is a better way of imagining it.

The African wild dog evolved as a specialized form of Xenocyon that could prey almost exclusively on antelope and other ungulates native to the savannas of Africa.

The robust Xenocyon went extinct, as did all of those possible insular forms, leaving only the specialized Lycaon pictus as a relict of what was once a more diverse line.

The African wild dog is truly a unique species, and to think of its story within this context should increase the urgency to conserve this species.

It’s truly a remarkable animal.

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One should note that there are other species that are called African wolves. All of these are members of the genus Canis and are in no way related to African wild dogs or Xenocyon.

The most famous of these is the Ethiopian wolf (Canis simensis), which is no longer classified as a jackal. The original molecular genetic studies of this wolf found that it was a descendant of Canis lupus.   A more recent study that they were not actually derived from the wolf, but they were very closely related to both wolves and coyotes.

The golden jackal is more closely related to wolves and coyotes than to the other two species of jackal,  so it could also be called an “African wolf.”

And there are two populations of golden jackal that are quite wolf-like.

One of these is the Egyptian jackal. It may be its own species (Canis lupaster), a subspecies of wolf (Canis lupus lupaster), or part of the golden jackal species (Canis aureus lupaster). It is found in Egypt and Libya, and it looks more like an Arabian or Indian wolf than a golden jackal. Because of this similarity, it was always classified as a type of wolf. Recent MtDNA studies show that it is some form of jackal, but the variance in the MtDNA sequence is pretty high from the closest golden jackal population.

Of course, MtDNA studies can be limited in their scope.

MtDNA is inherited via the mother, and we know that the only hybridization between dogs and wolves and golden jackals is between male dogs and wolves and female jackals. Male jackals just are unable to subdue female dogs or wolves to mate with them.

It could be that there was once a true Egyptian wolf.  Through intense persecution, it was reduced to very small numbers.  Male wolves were unable to find bitch wolves with which to breed, so they mated with female golden jackals.

And that could explain why these wolf-like dogs come out with golden jackal MtDNA.

Or maybe the hybridization happened very long ago with some canid that was closely related to the golden jackal, which would explain why the MtDNA of Egyptian jackals varies so much from Israeli golden jackals.

To make matters more complicated, a similar wolfish jackal has been found in the Danakil in Eritrea. It is called the wucharia, and the people who live there recognize it as something unique from the more common golden jackals that also inhabit the desert.

It may actually be a population of Arabian wolf, or it may be the same species or subspecies as the Egyptian jackal.

Both the Egyptian jackal/wolf and the wucharia could be modern day versions of African wolves. Maybe we should look to them to see where the African wolf population went.

We do know that Canis lupus did invade northern Africa at some point, but no one is sure how far south they got.

Or what happened to them.

When the original molecular genetic study came out on the Ethiopian wolf, it was though that the Ethiopian wolf was last surviving population of African Canis lupus.

I think it is very likely that there were African wolves, but these became extinct. Perhaps due to persecution. Perhaps due to competition with other carnivores.

A few individuals survived in North Africa and maybe in parts of the Horn of Africa, where they interbred with golden jackals or a close relative of that species as their numbers dwindled and these wolf populations became isolated.

Whatever these wolves were, they were likely very closely related to the Middle Eastern subspecies. They were probably the same subspecies that we call the Arabian wolf or maybe the Iranian wolf.

If this is true, then these would have been the first wolves that man encountered.

We now know dogs were first domesticated from Middle Eastern wolves.

However, those Middle Eastern wolves could have been living in North Africa when they first encountered humans.

It is possible.

And worth considering.

But the archaeological evidence shows that the domestication most likely happened in the Middle East, not North Africa.

It’s  still an idea to keep in mind.

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Arabian wolves are well-documented in Egypt.

They are found in the Sinai, which is the land bridge that connects Africa and Asia.

If any wolves could live in Africa, they would be something similar to these animals.

They aren’t big.

They really aren’t bad.

They are nothing like Xenocyon lycaonoides— the big, bad African wolf.

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Remember my query about Cubacyon transversidens and Indocyon caribensis?

Both of these animals were originally classed as unique species endemic to cuba. Cubacyon was even called a “Cuban dhole,” if you can imagine anything quite so ridiculous.

But as the remains of these dog-like creatures were further analyzed, it was determined that these animals didn’t belong to any unique species.

They didn’t represent some unique genera either.

They were domestic dogs.

Nothing more.

Nothing less.

But still I like to think that Cuba was once home to a dhole.

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Cuba wasn’t the only island to have a “fake dhole.” (I don’t know why so many people have thought island canids were dholes, but it’s been repeated time and again.)

Sardinia and Corsica were had “dholes,” too. It wasn’t a real dhole at all.

It was derived from Xenocyon, which is the ancestor of Lycaon pictus (African wild dog or “painted wolf.”)

The actual dhole probably was not derived from Xenocyon. It was an early offshoot from the Canis line.

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