rewriting history

Marion Bonner at the quarry site in 1971 where the fossil was discovered which has now been named Bonnerichthys in honor of the fossil hunting family.

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By Rod Haxton, editor

______________

Fossil find

named for

Bonners solves

mystery for

paleontologists

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Chuck Bonner had grown up walking the Smoky Hill River basin of southern Logan and Gove counties.

He had spent countless hours with his father and seven siblings climbing the bluffs, walking the ravines and carefully searching the shale for fossils tens of millions of years old.

The expeditions were led by his father, Marion, an accomplished, but self-taught, expert who had spent most of his adult life investigating the area’s landscape and making discoveries that were helping paleontologists gain a more complete picture of prehistoric life that existed in this region when it was covered by the Western Interior Sea that split the North American continent.

On this particular weekend, Chuck was home for a rare visit from Ft. Hays State University where he was an art student and employed part-time at the Sternberg Museum. It was August of 1971 and he, along with his younger brother, Dana, were fossil hunting in south-central Logan County, south of Lone Butte.

Chuck was experienced enough to know that one rarely, if ever, finds a fossil along the tall bluffs which are a common feature of this beautiful and rugged terrain.

“For some reason, Dana and I decided to hunt the high bluff,” he recalls. “The high points and vertical services usually aren’t a good place to hunt, but when you’re 21 you don’t mind climbing around,” he says with a wry smile.

While scaling a 40-foot butte the Bonners referred to as “The Big Place,” Chuck noticed something dark emerging from one of the chalk spires. What appeared to be bones were jutting out about two inches.

Digging some foot holes into the face of the bluff, Bonner began to carefully dig around the object to get a better idea of what lay beneath. His first instinct was that it was a fin, perhaps from a snout fish or a Xiphactinus, which was common in these ancient waters.

“I wasn’t that excited about it,” he recalls. “To me it was just a big fin.”

Chuck returned to college while his father spent four days excavating the site until he could make a plaster cast that would hold the fossilized remains in place.

The cast was then lowered by ropes about 40 feet to the bottom of the ravine where it could be loaded into the Bonner’s fossil-hunting vehicle “Spiker,” a 1949 Chevrolet Suburban which Chuck still takes on fossil hunts today.

Marion knew the fossil they had uncovered was not a common snout fish or swordfish, though it would take nearly 40 years before others in the world of paleontology agreed.

The Bonners not only changed history, but now have a fish genus named for them.

The Bonnerichthys, as scientists now refer to Chuck’s discovery, was a unique, albeit huge, fish measuring 20-25 feet in length with eyes six inches wide. It wasn’t a ferocious sea-dweller, but instead was a filter feeding fish, living on microscopic plankton.

That’s a big deal for paleontologists who believed that such fish had disappeared long before the age of dinosaurs.

Gathering Dust at KU

For more than two decades, this unique piece of the paleontology puzzle was stored in the basement of the Natural History Museum at the University of Kansas.

One of Chuck’s older brothers, Orville, was a preparator at the museum when the discovery was made, which is why the fossil was sent to him. Marion knew they had found something special, but he wasn’t sure quite what.

“What got to Dad was the round-shaped eye rings that were six inches across,” Chuck says. “That indicated this was a pretty large animal.”

However, this giant fish had no vertebrate and no spinal cord. It’s bone structure was held together by cartilage and tissue that can’t fossilize.

“We were very lucky that the skull stayed with the fins. This gave paleontologists a much clearer picture of what this giant fish looked like,” Bonner says.

“This was like the whale of the Kansas Cretaceous period, but it was a fish, not a mammal.”

Orville also felt his family had made a unique discovery and shared it with KU paleontologist Larry Martin, who was equally impressed. He termed the fossil remains as a “barn-burner.”

Yet their excitement seemed confined to the Museum of History. One reason why many paleontologists dismissed the discovery as another snout fish was because most experts were in agreement that giant plankton-eating fish didn’t exist in our oceans during the age of dinosaurs, from 66-172 million years ago.

That didn’t answer the on-going mystery as to why such plankton-eaters were missing from fossil records for hundreds of millions of years, says Mike Everhart, adjunct curator of paleontology at the Sternberg Museum of Natural History, Hays.

“We had to conclude that there were no big filter-feeders in the oceans during the Age of Dinosaurs.”

Sharing the Discovery

But Martin never lost hope that the Bonner’s fossil would generate interest outside the KU Museum of Natural History. He would show the bones to paleontologists whenever they’d visit Dyche Hall, but no one could offer a better explanation as to what they were other than just another snout fish.

After all, there was little to go on other than mostly a skull and huge front fins.

Besides, notes Bonner, most of the attention in the fossil world is focused on dinosaurs. Fish just aren’t seen as “glamorous.”

“We all suspected it was something pretty unusual,” he says. “But we aren’t into writing papers. It really takes someone who wants to get into the scientific paper writing to bring notoriety to a discovery like this. The excitement for me and my family has been in finding and preparing the fossils we discover.”

Martin realized that if this was truly a filter feeder, then the discovery would be huge.

In the mid-1990s he sent the fish head to Colorado where it could be prepared by a commercial company. It was at that time Matt Friedman, a scientist completing his PhD from the University of Chicago, came upon the fish head and grasped the significance.

Bonner credits Friedman with being the individual who finally shed light on the discovery.

“For the first time this became associated with the Cretaceous period, which was huge,” he points out. “It creates more interest in the Cretaceous period. It shows that not only were the dinosaurs killed off during this time, but also all the plankton in the ocean.”

Friedman, who later went to work in England, saw identical species of fish at the University of Oxford’s Department of Earth Sciences. The same fish, which had been misidentified by scientists, were also found in Britain and Japan.

Scientists were gradually getting a clearer picture of this genus, which thrived from 172 million years ago to 65 million years ago.

The discovery impressed Nick Pyenson, a whale paleontologist with the Smithsonian Institution, who says it solves a long-standing mystery. Today’s oceans have a number of large filter feeders and scientists have been curious why similar creatures were missing from early fossil records.

“The fact we didn’t see these suspension-feeding filter feeders was really kind of a big question mark,” says Pyenson. “Where were all these guys?”

Scientists now know they were there all along - just overlooked.

One reason they were overlooked, or misidentified, lies in their anatomy, explains Friedman. Over their evolutionary history, these fish reduced the amount of bone in their skeleton, probably to save weight. As a result, when they died most of their hard parts were scattered.

“As it turns out, the only parts you routinely find in the fossil record are their well-developed fore fins,” he says.

Similar plankton-eating fish were found in much older rocks in England and Europe, but scientists thought they were a short-lived and unsuccessful evolutionary experiment. Thanks to the Bonners, scientists now realize these fish had a longer history than anyone thought.

It’s interesting to note that the ancestors of large, modern filter feeders such as baleen whales and whale sharks only appeared after the extinction of Bonnerichthys and its relatives. This suggests that today’s filter feeders evolved to fill the ecological vacancy left by the extinction of these plankton-eating contemporaries of the dinosaurs.

Genus Named for Bonners

This isn’t the first time the Bonner family has been recognized for their discoveries in the fossil-rich beds of Western Kansas. Their discoveries can be found in museums in Kansas, Chicago, Los Angeles and elsewhere.

A few invertebrates named for them include Pecten bonneri (fossil scallop), Pteranodon bonneri (a flying reptile) and Niobrarateuthis bonneri (an ancient squid).

A genus, however, is a pretty big deal.

A genus is a grouping of related animals. Wolves and dogs, for example, are members of the genus Canis. Donkeys, horses and zebras are of the Equus genus.

The Bonners have been recognized for adding a new genus to the list of nature’s creations.

Friedman named the fish genus discovered by Chuck and excavated by Marion as Bonnerichthys. The species they found in Logan County is Bonnerichthys gladius.

“This is a pretty big classification, not as big as a family, but it’s still pretty big,” says Bonner. “This tells a more complete story of the demise of filter feeding fish.”

Marion, who lived in Leoti, died in 1992, at the age of 81. A year earlier, Chuck and his wife, Barbara Shelton, opened the Keystone Gallery just off US83 Highway in southern Logan County.

Bonner still conducts fossil hunting expeditions and, on occasion, will discover smaller fins that he says could be babies of the Bonnerichthys gladius, or they could be another species entirely.

“Until we find cranial material we can’t be for sure,” he says.

While having a genus named for the family has created a lot of interest, in his typical demeanor, Chuck remains pretty low-key about all the publicity.

“I guess you could call this our 15 seconds of fame,” he says with a laugh.

Fame that was more than 65 million years in the making and which took nearly 40 years to unravel.

Then again, time and patience are two important ingredients in the world of fossil-hunting.

User Comments

RN
"As a young teenager I was invited to join my friend and classmate Clare J. Bonner and father Marion on western Kansas fossil hunt on several occasions. What a unique privelege and valueable experience it was. It changed my way of thinking about our precious earth and the history it holds. The Bonner family has shared with the science community their love of the historical world. Thank you Marion and Margaret Bonner and talented family members. "
Posted by Dorothy Clark on Mar. 12, 2010