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Tag: fossils

Bear dogs once roamed Texas, or, why it’s important to check that miscellany drawer

beardog

Every home has at least one — that drawer in which you place things that have no assigned place: rubber bands, soy sauce packets, take-out menus, the owner’s manual to that extinct VHS player you bought in the 1980s.

Such drawers become a crypt for things you mostly didn’t need to keep in the first place, but often there are some forgotten treasure mixed in with them.

The importance of revisiting the miscellany drawer from time to time is displayed in this story — about a researcher at the Field Museum in Chicago, new on the job, whose opening of a drawer of miscellaneous and not fully identified carnivore fossils led to the establishment of not just one new genus, but two and, in doing so, a better understanding of the evolution of dogs and other mammals.

“I had just started at the Field, and I was getting the lay of the land, exploring our collections,” Susumu Tomiya said. “In one room of type specimens, the fossils used as a standard to describe their species, I stumbled across something that looked unusual.

“There were beautiful jaws of a small carnivore, but the genus the specimen had been assigned to didn’t seem to fit some of the features on the teeth. It made me suspect that it belonged to a very different group of carnivores.”

That specimen, and a similar one Tomiya came across, had both been found 30 years ago in southwest Texas.

beardog-jawBoth had been labeled as belonging to a genus called Miacis, but Tomiya’s suspicions — based on the apparent sharpness of their teeth — turned out to be right.

The findings were revealed last week in a paper published in the journal Royal Society Open Science.

Tomiya and his coauthor used a computed tomography (CT) scanner to create 3D visualizations, and determined the specimens were those of amphicyonids, and the oldest known members of that family, which went extinct 2 million years ago.

Amphicyonids, commonly called bear dogs, are believed to be the ancestors of both bears and dogs.

“Ever since amphicyonids were given their common name, they have been overshadowed by the bear and dog families, which are more widespread, better known today, and less extinct! Our study provides a renewed sense of identity to a group that left their own mark during their 38-million-year history,” Tseng said.

Amphicyonids ranged from the size of a Chihuahua to the size of a brown bear.

They tended to get larger throughout their evolutionary history, which might have contributed to their extinction.

(At top, artist’s reconstruction of a 38 million year old amphicyonid, by Monika Jurik; lower photo, the jawbone of an amphicyonid; both provided by The Field Museum)

Fossils found in Maryland identified as those of ancient dog species

cynarctuswangi

If you were wandering around Maryland 12 million years ago, you might have run into this fellow.

You wouldn’t have know what to call him, though, because only now does his species have a definite name — Cynarctus wangi.

Fossils found by an amateur collector along the beach under the Choptank Formation in Maryland’s Calvert Cliffs region have been identified as the news species of ancient dog by a doctoral student at the University of Pennsylvania.

The specimen, found in Maryland, would have roamed the coast of eastern North America approximately 12 million years ago, Science Daily reported.

Among species that still roam the earth, Cynarctus wangi probably most closely resembles the hyena.

“In this respect they are believed to have behaved in a similar way to hyenas today,” said Steven E. Jasinski, a student in the Department of Earth and Environmental Science in Penn’s School of Arts & Sciences and acting curator of paleontology and geology at the State Museum of Pennsylvania in Harrisburg. His new findings were published in the Journal of Paleontology.

Fossils from terrestrial species from the region and time period are rare, he said.

“Most fossils known from this time period represent marine animals, who become fossilized more easily than animals on land,” Jasinski said. “It is quite rare we find fossils from land animals in this region during this time, but each one provides important information for what life was like then.”

Jasinski and Steven C. Wallace, a professor at East Tennessee State University, began their study after the specimen was placed in the Smithsonian Institution.

Initially, they presumed it was a known species of borophagine dog, a species called marylandica that was questionably referred to as Cynarctus, a fossil of which had been found in older sediment in the same area.

But when they compared features of the teeth of the previously known and the new specimens, they found notable differences and concluded the specimen represented a distinct species new to science.

“It looks like it might be a distant relative descended from the previously known borophagine,” Jasinski said.

Borophagine dogs were widespread in North America from around 30 million to about 10 million years ago. The last members went extinct around 2 millions of years ago during the late Pliocene.

Cynarctus wangi represents one of the last surviving borophagines and was likely outcompeted by ancestors of some of the canines living today: wolves, coyotes and foxes.

The name of the new species honors Xiaoming Wang, curator at the Natural History Museum of Los Angeles County and an expert on mammalian carnivores.

(Illustration from “Dogs, Their Fossil Relatives and Evolutionary History,” courtesy of the University of Pennsylvania)

Study says dogs go back no more than 12,000 years

skulls

A new study has a bone to pick with earlier researchers who concluded the domesticated dog has been around for 30,000 years.

New 3D analysis of skulls that had been identified as two of the earliest dogs shows they were actually wolves, a research team writes in the Nature journal Scientific Reports.

Fossilized remains that scientists said showed dogs date back at least 31,680 years — specifically those remains unearthed at Goyet Cave in Belgium — actually belonged to a wolf, according to a new study. So too, the new study says, did a 13,905-year-old fossil that was identified as belonging to a dog after it was found at a site called Eliseevichi in Russia.

The new study concludes that the the domestication of dogs happened during the Neolithic era (10,200 B.C.-2,000 B.C.) as opposed to the Paleolithic era (2.6 million years ago to 10,200 B.C.)

“Scientists have been eager to put a collar on the earliest domesticated dog,” lead author Abby Grace Drake said. “Unfortunately, their analyses weren’t sensitive enough to accurately determine the identity of these fossils.”

“Previous research has claimed that dogs emerged in the Paleolithic but this claim is based on inaccurate analyses,” Drake told Discovery News. “We reanalyzed some of the fossil canids from the Paleolithic and show that they are, in fact, wolves.”

“We did confirm that the Neolithic specimens Shamanka II (around 7,372 years old) and Ust’-Belaia (about 6,817 years old) are dogs, and therefore domestication took place by this time period or earlier,” added Drake, an assistant professor of biology at Skidmore College.

That means the wolves — who are generally (but not unanimously) believed to have evolved into dogs, possibly as a result of their interacting with humans — first appeared on earth after humans were farming and living in settlements, as opposed to when they were living in caves and hunting and gathering.

Drake and colleagues Michael Coquerelle and Guillaume Colombeau used scans and 3D visualization software to study the shape and size of the two oldest skulls and compare the data with measurements from the skulls of other dogs and wolves, according to a report on Phys.org.

That technique allowed the team to identify subtle morphological differences between dogs and wolves, such as the direction of the eye cavity and the angle between the muzzle and forehead.

(Photo: Abby Grace Drake, Skidmore College)

World’s first dog believed discovered

An international team of scientists has identified what it believes is the world’s first known dog, and says that it lived in Belgium 31,700 years ago — a good 17,000 years earlier than what was previously thought to be the earliest dog, found in Russia.

The prehistoric dog’s remains were excavated at Goyet Cave in Belgium, suggesting to the researchers that the Aurignacian people of Europe from the Upper Paleolithic period were the first to domesticate dogs, the Discovery Channel reports

“The most remarkable difference between these dogs and recent dog breeds is the size of the teeth,” lead author Mietje Germonpre told Discovery News, comparing the tooth size more to wolves than dogs.

The scientists say — based on Isotopic analysis of the bones found — that the earliest dogs subsisted on horse, musk ox and reindeer.

Germonpre, a paleontologist at the Royal Belgian Institute of Natural Sciences, said the Paleolithic dogs most resemble the Siberian husky, but were somewhat larger.

For the study, which has been accepted for publication in the Journal of Archaeological Science, the scientists analyzed 117 skulls of recent and fossil large members of the Canidae family, which includes dogs, wolves and foxes.

Germonpre believes dog domestication might have begun when the prehistoric hunters killed a female wolf and then brought home her pups.