Texas Dig Focuses on Small Finds: Scientist Claims Tale of Dinosaur Forebears is in the Teeth

Jun 18, 02:09 AM

Current Headlines: By Derek Kravitz, The Dallas Morning News

Jun. 18--SEYMOUR, Texas -- Robert T. Bakker picks out a 275 million-year-old tooth from the red-colored dirt on this massive northwest Texas ranch, examines it with a trained eye and promptly sticks it in his mouth.

"It feels like silt mixed with peanut butter," says Dr. Bakker, as he tastes the tooth from a Dimetrodon, a 500-pound, finned reptile that predated dinosaurs. "It has a smooth, creamy texture from the clays."

The visiting curator at the Houston Museum of Natural Science revolutionized the paleontological world three decades ago with research that suggested dinosaurs were warm-blooded, fast-moving creatures, not sluggish lizards.

Now, Dr. Bakker, a Yale-trained paleontologist, is stirring controversy again among dinosaur hunters with an approach he created that looks at fossils in the same way forensic scientists comb through crime scenes.

"Traditionally, paleontologists haven't paid much attention to a shed tooth. It's a little item. However, from a criminological point of a view, it's the most important thing you can find," Dr. Bakker said. "It's proof of who ate whom and where. These deposits are full of bullets -- shed teeth. We know who the perps were and who the vics were."

Colleagues dismiss many of Dr. Bakker's ideas as unworthy hype, calling him a heretic, a nut and worse.

"That's what any paleontologist already does, a CSI-type look at fossils. It's nothing new," said Michael K. Brett-Surman, museum specialist for dinosaurs at the Smithsonian Institution in Washington.

But Dr. Bakker, a 62-year-old Pentecostal-preacher-turned-paleontologist with a scruffy white beard and a worn cowboy hat, disagrees. He says his method of looking at previously unheralded fossils, such as teeth, could yield fascinating new insights about the ecological evolution of the Texas red beds -- red earth full of fossils.

"This is like an episode of Law & Order where, before the first commercial break, you find out who the victim is and how he or she died," Dr. Bakker said.

Researchers from the Houston museum are banking on Dr. Bakker's theories.

They hope a few choice excavations will produce some new skeletons for display, provide a clearer, three-dimensional picture of what Texas looked like millions of years ago and answer lingering questions about where dinosaurs came from.

A peek at the Permian

Since the early 1900s, paleontologists and archaeologists have scoured the red beds of northwest Texas in search of the "missing link" between the pre-dinosaur reptiles of the Permian period and the dinosaurs often associated with those in the movie Jurassic Park.

The mad dash to northwest Texas picked up a frenzied pace in 1917, when paleontologist Charles H. Sternberg and his two sons found Dimetrodon skeletons at the Craddock Ranch in Seymour.

But the Sternbergs missed a few things, experts say.

"There are lots of little things the Sternbergs left behind. They said, for example, that they couldn't find the Dimetrodon toes. But they weren't really looking for toes," said David Temple, the Houston museum's associate curator of paleontology. "They were looking for the big stuff."

So over the past year, Dr. Bakker has brought teams of geologists, educators and museum curators to the tiny town about 150 miles northwest of Dallas.

Here, they search for tiny evidence of the world as it was roughly 275 million years ago, before most of the earth's life was wiped out by mass extinction.

Back then, the Texas interior lowlands were near the ocean. Heavy rains created a rich, red-colored earth. But it was hot, with temperatures upwards of 100 degrees all year round.

Tree ferns, conifers and vegetation-choked ponds and swamps abounded. Fierce-looking, 4-foot-tall reptiles roamed the earth looking for food. They fed on sharks that looked similar to modern-day coelacanths, the oldest living jawed fish that date to about 400 million years ago and swam in the region's meandering rivers.

But it was relatively quiet. There were no birds. Reptiles, like the Dimetrodon, were deaf. The only sounds were the deep croaking of 500-pound toads.

Dr. Bakker's team so far has collected 1,000 bones from the early Permian period, including two species of Dimetrodon, partial skeletons of a Diplocaulus, a large amphibian also known as a "Boomerhead" for its boomerang-shaped skull, and cartilage from a 6-foot, prehistoric, freshwater shark called a Xenacanth.

The fossils are identified, bagged and taken back to Houston to be cleaned and cataloged. Eventually, the bones will be displayed.

One of the bones found last week -- a complete hipbone from a Dimetrodon -- will go into the museum's grand hall in the next few days.

But it's the grand prize -- a full skeleton -- that could bring droves of visitors to Houston's museum district, as the science museum begins planning for a major exhibition hall.

Varying views

Still, some paleontologists say Dr. Bakker's work is behind the times.

New discoveries of bigger dinosaurs and feathered birds in Argentina and China are setting the paleontology world abuzz, not fossils from the pre-dinosaur period in Texas, said Dr. Brett-Surman, the Smithsonian's dinosaur guru.

Last week, remains of a newly discovered, 16-foot-tall, 3,000-pound prehistoric bird called Gigantoraptor elrianensis were found in Inner Mongolia in China.

Other paleontologists defend Dr. Bakker's research as fresh, even if on a much smaller scale than some fossil-seeking counterparts.

"This has been already looked at, but to a much lesser degree and about more general issues of abundance and fairly typical diversity patterns in the run-up to extinction," said Thomas R. Holtz Jr., a vertebrate paleontologist and senior lecturer at the University of Maryland at College Park. "Dr. Bakker is trying to answer far more specific ecological questions about other species and how they relate to one another."

Dr. Bakker, generally regarded by colleagues as a lightning rod for criticism and a media hound, said his work is bound to provoke some questions from head-scratching scientists.

But the truth, he says, is in the teeth.

"A lot of the questions have all been answered by theories and hypotheses," he said. "We didn't have the smoking jaw. That's where the answers are."

PERIODS STUDIED BY PALEONTOLOGISTS

The Paleozoic era started 540 million years ago with bacteria and algae, and finished 250 million years ago with forests of primitive plants, species of fish and reptiles that roamed present-day Africa and were the ancestors to dinosaurs.

The Permian period, a 50 million-year stretch Robert T. Bakker of the Houston Museum of Natural Science is focusing on, showed the first sign of mammalian life with the emergence of primitive reptiles. It ended with an "extinction event" that wiped out nearly all significant life.

The Mesozoic era, called the "age of the dinosaurs," covered 180 million years, from 250 million years ago to 65 million years ago. Dinosaurs and aquatic reptiles flourished in the first half of the era, while smaller animals, including snakes, lizards and primates, evolved toward the end of the era.

Meaning "new life," the Cenozoic era is ongoing and covers the last 65.5 million years. It includes large mammals, the evolution of most modern-day birds and the abundance of co-dependent plants and insects.

-----

To see more of The Dallas Morning News, or to subscribe to the newspaper, go to http://www.dallasnews.com.

Copyright (c) 2007, The Dallas Morning News

Distributed by McClatchy-Tribune Information Services.

For reprints, email tmsreprints@permissionsgroup.com, call 800-374-7985 or 847-635-6550, send a fax to 847-635-6968, or write to The Permissions Group Inc., 1247 Milwaukee Ave., Suite 303, Glenview, IL 60025, USA.