Martinogale faulli, holotype, LACM 56230, skull and jaw resting on top of a penny.
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A Skunk's Story
By Natural History Museum staff writer Kristin Friedrich, published in June 2006 issue of the Naturalist. Photograph of the skunk skull (left) is published on the cover of the Nauralist. (download PDF file here)
A skunk’s self-defense mechanism is notorious. But its genealogy, of late, has become notoriously controversial. The Natural History Museum’s Xiaoming Wang, David Whistler and Gary Takeuchi have described a new species of fossil skunk, and in doing so, altered traditional views on the animal’s evolution.
Interestingly, the 9-million-year-old specimen was discovered in the Mojave Desert’s Red Rock Canyon State Park—two hours from Los Angeles. Red Rock is a well-known fossil site, thanks largely to Whistler’s work there. In addition to small animals, the sediments have revealed extinct elephants, rhinos, three-toed horses, giraffe-like camels, saber-toothed cats, and bone-crushing dogs. “It’s important for people to understand that right in the backyard of Southern California, we can still discover world-class specimens,” Wang says.
The fossil was named Martinogale faulli in honor of former park ranger Mark Faull; its describers call it “Faull’s skunk.” It was discovered in 1974, and brought to the Museum by Whistler. When Wang, an expert on carnivores, came to the Museum in 2001, he suspected the fossil’s significance.
Consisting of an excellently preserved skull and mandible, it’s the earliest, most primitive, and smallest of all North American skunks. In life, the animal would have been less than a foot long, including its tail, and weighed just a few ounces.
Skunks originally came from Asia, via an ancient land bridge between Siberia and Alaska—making Faull’s skunk the oldest known evidence of this prehistoric migration from the Old World. “It has somehow preserved all of the ancestral features of a skunk, so even though it’s younger than the European ones, it’s more primitive,” Wang says. “We can’t really use European forms to get a handle on ancestral skunks. That’s what’s so wonderful about this one.”
Because of the gland that provides their malodorousness and a specialized shearing tooth, skunks have long been considered part of the weasel family Mustelidae. But skunk genealogy has become controversial recently. DNA studies on living skunks now suggest they may come from a separate, more ancient lineage of carnivores—and belong to a family of their own.
Faull’s skunk just makes things more interesting. It has the shearing tooth of the weasel family, but a primitive upper molar of the subfamily Mephitinae, indicating that perhaps skunks are more ancient than previously thought. And if this is true, then the specialized traits of mustelids and mephitines have evolved independently, twice.
Wang says he’ll continue working on the question of the skunk’s background. “I have to compare this to a broad range of early primitive carnivores. If the skunks are a part of a very ancient family, then they are probably in line with the origins of other families—dogs, weasels and bears, for instance. All these individual families go back 20 to 30 million years, so the story isn’t over yet.”
References:
Wang, X., D. P. Whistler, and G. T. Takeuchi. 2005. A new basal skunk Martinogale (Carnivora, Mephitinae) from late Miocene Dove Spring Formation, California and origin of New World mephitines. Journal of Vertebrate Paleontology 25(4): 936-949. PDF download (0.3 Mb)
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