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Archive for the ‘Taxonomy’ Category

coyote profile pic

I am a coyote lover. No two ways about it.  I have always been interested in wolves and dogs, but in the past couple of years, I’ve had encounters with Eastern coyotes.  And they are every bit as fascinating. Western man has thrown every single weapon he could contrive at them, and all they have done is spread all over the continent.

So it was with great joy when I got a chance to read Dan Flores’s  Coyote America. I had heard the author interviewed on Steven Rinella’s podcast a while back, and I was really fascinated about what he had to say about Pleistocene megafauna on the North American Great Plains.

I also knew he was writing a book on coyotes, and I wanted get his take on them.

I’ve just started reading the book. I really enjoy his discussion about Native American traditions with coyotes. I am a damned, no-good Easterner, so I know very little about those traditions.

But I do have a quibble. It’s a friendly quibble. In one part of the book he describes coyotes as being as genetically distinct from wolves as humans are from orangutans and that the two species split from a common ancestor some 3.2 million years ago. He uses a lot of the paleontological data from Xiaoming Wang, who is a great canid paleontologist, who posits that coyotes evolved from directly from Canis lepophagus and that they are wholly a North American lineage.

Now, this is paleontology, and it’s not exactly the best way to determine evolution relationships between very closely related canid species. The reason why is that canids have a tendency toward parallel evolution. For example, the bush dog of South America has dentition that is very much like the African wild dog and the dhole, and at one time, it was suggested that the bush dog was actually a species of dwarf dhole. We now know from genetic studies that it is actually a close relative the of the maned wolf, and it is well-nested in the South American canid clade.

It is definitely true that coyotes resemble African golden jackals, but similarities in appearance have led to error here.  Molecular geneticist have recently found that African golden jackal is actually much more closely related to coyotes and wolves than it is to the Eurasian golden jackal. That means that two animals we thought were the same species actually turned out to be two.

And when it comes to the relationship between coyotes and wolves, molecular geneticists had long assumed that the two species split around 1 million years ago.  In countless dog domestication articles, the molecular clock has been calibrated around a 1-million-year-old split between wolves and coyotes. I have always thought that was weird, because the paleontology studies suggested a much older divergence.

Well, a recent comparison of wolf and coyote genomes from across North America revealed that the actual separation time was something more like 50,000 years ago. That means the animals we’re calling coyotes now aren’t the same thing as those million-year-old fossils.  Those animals are of evolutionary dead-ends that just happened to have a very similar morphology to a coyote in much the same way that African and Eurasian jackals do. Of course, we cannot get genetic data from such old fossils, but it could be that some of these dead-end canids might be more closely related to black-backed and side-striped jackals, which really did diverge from the rest of Canis a really long time ago. They are more divergent from the rest of Canis than the African wild dog and dhole are, and the dhole and African wild dog have their own genera.

If coyotes and wolves diverged only 50,000 years ago, then this raises an interesting taxonomic question. All extant wolf lineages diverged in the past 44,400-45,900 years, as a recent study comparing wolf genomes revealed.  These means the genetic difference between a wolf and a coyote is not much more than the greatest genetic variance between wolves. (Generation time are roughly similar in both wolves and coyotes).

This means that the creatures we’re calling coyotes now actually derived from the Eurasian wolf. The reason this animal looks so much like a jackal isn’t because it represents a primitive North American Canis lineage, but because the larger, pack hunting wolf from Eurasia couldn’t live very well at middle latitudes in North America. At the time, dire wolves were occupying this niche. There were also dholes coming into North America, which means that the pack-hunting wolf of Eurasia really had some strong competition. That means that these wolves evolved more toward the generalist jackal body-type and ecological niche. They did so in parallel to the Eurasian and African jackals.

This is very similar to what happened to the first radiation of Eurasian lynx into North America. Eurasian lynx are pretty large, weighing as much as 70 pounds, but they found the mid-sized cat niche already locked up in North America. So they evolved into the smaller bobcat. It just happened millions of years before the wolves that became coyotes came into the continent.

The fact that wolves and coyotes are this closely related and have exchanged genes so much across the continent raises some important questions about what a coyote is. The comparative genome study on wolves and coyotes showed that the animals called the Eastern wolf and the red wolf, which Flores considers valid species in the book, are actually hybrids between wolves and coyotes. I’ve long been a skeptic of the red and Eastern wolf paradigm, but this study actually makes me question coyotes.

One could actually argue that coyotes are a subspecies of wolf. This is a controversial thing to say, but it was once controversial to say that dogs and wolves were the same species– and now there is growing acceptance (at least among scientists) of this fact.

It is certainly true that all wolves, jackals, African wild dogs, and dholes do descend from a coyote-like North American ancestor.  But to assume that coyotes are directly derived from this ancestor is a major error, and one that has been falsified in the molecular studies.

If my interpretation of the genetic studies is correct, the coyote should be called the “thriving wolf.” Unlike the bigger ones, it was able to survive all that we threw at it. The more we persecuted it, the greater its numbers became, as did the vastness of its range. It is an adaptable, resourceful survivor, and that makes it the perfect “American avatar” to use Flores’s construction.

So that is what a coyote is.  It is the wolf that thrives.

 

 

 

 

 

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pale fox

One of the least studied of all canids is the pale fox (Vulpes pallida). It is native to the Sahel, a region in North Africa that lies between the Sahara and the savannas.

It was always assumed that the pale fox was a true vulpine fox, perhaps closely related to the fennec, which lives just to its north in the Sahara proper.

However, a new study out of the Russian Institute for Cytology has revealed something truly shocking.  Not only is the pale fox not a true fox, it actually is much more closely related to the black-backed and side-striped jackals than to any other canid.

Researchers traveled to Senegal and Mali and spent eighteen months live trapping the little foxes.  Initially, the researchers thought it would be quite difficult to capture enough specimens for the study, but it turns out that pale foxes are very easy to trap. All it took was just a bit of sheep fat and marten glands to lure the foxes into live cage traps.

The researchers were able to capture 21 in Senegal and 17 in Mali. They took blood samples from the foxes, which were sent to St. Petersburg.

At St. Petersburg, the researchers were able to extract good quality samples of mitochondrial DNA, which were then compared to the mitochondrial DNA of other extant canids. Mitochondrial DNA is inherited from the mother’s line, and it can be used to determine evolutionary relationships among various species.

The studies found that the samples of mitochondrial DNA of pale foxes most closely matched the black-backed and side-striped jackals than any of the fennecs, red foxes, and Rüppell’s foxes in the study. They were also similar to wolves, domestic dogs, and golden jackals.

Dr. Igor Iljin, head researcher on the study, says that the findings are truly a surprise.

“What we have found is that the pale fox is actually a jackal that has evolved into roughly the same niche as a desert fox. Our analysis of the mutation rates suggest that the pale fox only split off from the black-backed/side-striped jackal clade about 3.5-4 million years ago.”

Because black-backed jackals have been around in their present form for around 2-3 milion years, Iljin thinks that the pale fox evolved from jackals that became stranded in the Sahel around that same time period. Over time, they adapted to a more specialized diet of insects and small rodents. They also became significantly smaller to adapt to such a nutrient-poor diet.

Because the pale fox resembles the fennec in its ecology and morphology, it was assumed that these two species would be the most closely related.

However, this study shows that the pale fox’s similarity to the fennec are the result of convergent evolution.

“Just as convergent evolution produced a placental wolf in Eurasia and a marsupial wolf in Australia,  it has also produced two very similar arid-zone “foxes” in Africa,” Dr. Iljin concludes.

Further, Dr. Iljin strongly suggests that we stop calling the pale fox by that name:

“From now on, it should be referred to as the ‘pale jackal,’ and its scientific name should be updated to Canis pallida. Of course, we are aware that that the exact position of this endemic African clade of canids may or may not be properly classified within Canis, and if that were to change, we would expect the pale jackal to be placed with its closest relatives.”

So there we have it.  What was once thought to have been a fox is actually a jackal.

DNA has found stranger things before!

So we have a new species in Canis, which was once Vulpes.

Convergent evolution hid a dog in fox’s clothing.

***

Important note.

 

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baby snake

It was in a light fixture.

It was about 7 or 8 inches long. It was about twice the diameter of a pencil.

It didn’t try to bite.

Can you guess the species?

Leave answers in the comments.

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