Category Archives: Animals

SuperCroc at Sternberg

The Sternberg Natural History Museum at Fort Hays State University is featuring a new exhibit, The Science of SuperCroc from now until August 5.

The star of the show is the African crocodilian species Sarcosuchus whose remains have been found in the modern Sahara, in the Elrhaz Formation. This Early Cretaceous (~112 million years ago) crocodile had a long, slender snout with a prominent down-turn or hook at the tip. When fully mature it is estimated to have been between 37-40 feet in length, and weighed as much as 17,000 pounds.

The largest living crocodile is the saltwater croc, and the largest confirmed individual was just over 20 feet in length and weighed a mere 2,600 pounds.

Restoration of Sarcosuchus, the SuperCroc

Sarcosuchus had its eyes placed high upon its skull suggesting that it spent most of its time submerged in the water. Like so many other things in paleontology, the question of what Sarcosuchus may have eaten is not agreed upon by researchers. Some suggested that the size of Sarcosuchus and its overhanging upper jaw made it able to wrestle large prey items, even massive long-necked sauropod dinosaurs. Others point to the slenderness of the muzzle and it not looking stout enough to withstand the forces that would be required to bring down large prey. There were plenty of lobe-finned fish in Sarcosuchus’s environment. I see a fish-eater in this skull myself.

Also on display with the large croc is Suchomimus, a theropod dinosaur whose remains have been found in the same geological formation as Sarcosuchus. Suchomimus, whose name means crocodile mimic, was a forty-foot long beast which also had a long slender muzzle. Its forelimbs were armed with very long sickle-curved claws. This animal is thought to have eaten fish and probably other sorts of meat, but its skull also does not appear equipped for biting and holding very large struggling prey.

SuperCroc Sarcosuchus skeleton at Sternberg Museum

The presence of both of these animals, and many others found with them, show that the Sahara area of today was a lush, swampy habitat in the Early Cretaceous. The effect of climate change and plate movements over millions of years can turn a wet verdant habitat into a harsh, dry desert. My how times change.

Go see SuperCroc at the Sternberg Museum if you have a chance.

Scientifically Authenticated Dinosaur Model Kits Now Online

Guest Post

For the Dinosaur connoisseur and collector, you will find what you have been looking for at Dinosaur Model Toys.com. The creator of all the works featured on this site is not only a gifted sculptor, but actually works with dinosaur fossils as a paleontological reconstruction artist, fossil preparator, and field technician at the Natural History Museum of Los Angeles. His artwork is based on the latest scientific research, real fossil material, and years of hands on experience. This is why the work featured is regarded as some of the most scientifically accurate available to the public.

The new Dinosaur Galleries at the Natural History Museum of Los Angeles will feature many of the artist’s creations. Most notable is the baby Tyrannosaurus rex estimated to have been two years old when it died, for which nearly ninety percent of the skeleton will be recreated for this mount. This sculpted reconstruction will be featured with two real T-rex specimens, one a six-year old, and the other the sub adult specimen named “Thomas” which Doyle Trankina helped collect, and prepare. Thomas is estimated to be about seventy percent complete, making it one of the top five most complete in the world. Our initial offering will be a series of cast resin models and limited edition bronze sculptures with both a highly detailed exterior view, and a rendition of the internal skeletal anatomy of an adolescent T-rex similar to the Thomas find.

As part of the Dinosaur Institute at the Natural History Museum of Los Angeles Doyle Trankina has attended several field excavations in Montana, Utah, and the Mojave. While in the field Doyle prospected, and assisted in the collection of several specimens, most notably Thomas the sub adult Tyrannosaurus rex that will be gracing the museum’s new Dinosaur Gallery in 2011. Through his experiences with the museum with his private obsession with prehistoric life and the natural world, Doyle has produced several sculptures and illustrations for exhibition and publication. Doyle has an extensive list of sculptures to produce over the next two years. His work will require lots of observational study from the museum’s collection, and extensive extrapolation based on the latest research, and modern analogues like birds, and crocodiles.

After completing the preparation of Thomas, Doyle embarked on a half skeletal, half flesh reconstruction of an adolescent Tyrannosaurus rex at 1;24th scale. The detail and fidelity to the skeleton was accomplished by long study of the anatomy from several existing mounts, scientific publications, and photographs from the some of the best Tyrannosaurus specimens. The teeth were surfaced to provide the accurate thickness and semblance to where the tinny serrations would have lined the many teeth. Because the position of the serrations actually change on the teeth as they move back towards the throat, the ridge implies the appropriate location of the serrations. The scales were carved individually so that the skin wraps around the form in a realistic, and accurate way.

Doyle is currently working on a skeletal reconstruction of a baby Tyrannosaurus rex which will be mounted in the new Dinosaur Galleries with Thomas and an intermediate specimen as an illustration of age progression. The actual specimen is only known from a skull fragment from the snout of what is believed to be from a two-year-old Tyrannosaurus rex. There are no post cranial remains, and there are only a handful of examples that are believed to be that of baby dinosaurs. This project has just begun, and with Dr. Chiappe Doyle will be making history in presenting the worlds only mounted baby Tyrannosaurus rex specimen.

Fall of 2009 marked one of the biggest Paleontology news splashes, featuring N. America’s smallest dinosaur, Fruitadens haagarorum. Nearly 150 million year old, the tiny Fruitadens would have shared its life with such titanic beasts as Brachiosaursus, and Allosaurus in the late Jurassic. It is thought that the animal might have weighed as little as two pounds and measured only 28 inches in length. Fruitadens was discovered in Colorado in the late 1970s in a geological formation known as the Morrison, more specifically in an area called Fruita, for which the specimen was named after.

Artist reconstruction of the dinosaur Fruitadens

The strange dentition of this animal implies that Fruitadens might have been omnivorous, eating plants and at least insects if not small vertebrates. Doyle has produced the first and most accurate illustrated and sculpted reconstructions of this animal. Fruitadens belongs to a family of early dinosaurs called heterodontosaurids, which share many interesting features, one of which are the teeth. Fruitadens like other heterodontisaurids have varied dentition, and in the front of the mouth sits a canine like tooth on the lower jaw. His work was featured on every major news source in the world, and five of the sculpted Fruitadens will be featured in the new galleries in 2011. In his studio, Doyle is currently working on a scale Fruitadens, which will be approximately 30cm long . This will be the only scaled sculpture of the animal, and the first and only for sale. The full scale version is not for sale and can only be seen at the Museum.

Doyle is also concurrently working on Mamenchisaurus, a long neck dinosaur and part of the branch of Sauriscian (lizard hipped dinosaurs) known as Sauropods. As the prospects of obtaining a casting of the Chinese mamenchisaur skull proved too difficult, Doyle was charged with the task of reconstructing the skull from two dimensional reference and other dinosaurs like Camarasaurus for comparison, and to gain familiarirty with Sauropod skull anatomy. The rare skull was found in China and researchers provided a paper with a detailed description and several scientific illustrations. Sauropod skulls are rare because they are so frail in construction, have several small bones that usually disarticulated some time after the animal dies, and are not commonly preserved in fossilization, or are so disarticulated and in such small pieces that they are nearly impossible to find.

Doyle Trankina is a sculptor, illustrator and fossil preparator at the Los Angeles Museum of Natural History. For unique scientifically authenticated Dinosaur Art, Dinosaur Models and Dinosaur Resin Model Kits, visit his online store Dinosaur Model Toys.Com.

Many other interesting dinosaur facts can be found here at Boneblogger.

Niobrara Chalk

One of the most famous formations is the Niobrara Chalk. This formation is exposed in northwest Kansas and southern Nebraska. Formations are sometimes divided into members, subsections of the formation based upon its rock type. The Niobrara Chalk has two members: the lower Fort Hays Limestone and the upper Smoky Hill Chalk. It is the Smoky Hill Chalk which is best known for its fossils.

The sediments that comprise the Niobrara Chalk were deposited in the Western Interior basin during the Late Cretaceous. At that time sea levels rose and the interior of North America was inundated by a shallow sea, the Western Interior Sea. The sea cut North America in half by spreading from the Gulf of Mexico to the Canadian Arctic. Volcanoes to the west, in what is now Utah and Nevada, spewed ash into the sea and sediments eroded from mountains along the western coast were washed into the sea by rivers. What is today Kansas was much closer to the eastern shore of the sea, a low alluvial plain, also gently washing sediment into the sea basin.

Block diagram of the Western Interior Sea

Image from Hattin, 1982.

The upper member, the Smoky Hill, was deposited from 87 to 82 million years ago, so it preserves a five million year window into the past. Elsewhere we discussed that the Cretaceous sea had a wealth of planktonic organisms. Many of those organisms had calcium carbonate-based shells and body parts, which furnished a steady supply of material to sink to the sea floor. The consistent supply of sediment, both from land and sea, and conditions at the sea floor allowed for the excellent preservation of animals. Those that died and sank to the bottom were rapidly covered by the rain of sediment and entombed until today.

And the diversity of organisms preserved is amazing. In almost every museum with fossils that I have been in, I recognize fossils from Kansas. Giant marine reptiles (mosasaurs and plesiosaurs), flying reptiles (pterosaurs), great toothy fishes, large turtles, and toothed diving birds have all been found. Each of these groups has a very interesting story to share, and we will explore many of them here. An extensive website on fossils from the Niobrara Chalk can be found at OceansofKansas.com.

Giant Short-Faced Bear Reexamined

As the old saying goes, looks can be deceiving. That is the theme of a new paper on the Giant Short-Faced Bear (GSFB), Arctodus simus, recently published in the Journal of Vertebrate Paleontology (Figueirido et al., 2010).

We have explored this beast in other posts (see below), and will no doubt do so in the future, as it is one of my favorite animals because of the fascinating paradoxes that it presents. Bears as a group often do not do what we think they should do!

The GSFB is the largest mammalian carnivore known, fossil or recent. First discovered in Northern California and described by Cope in 1879, remains of this species have since been recognized from Alaska to Mexico, and from the west coast east to Pennsylvania in North America. It lived from about 1 million years to about 10,000 years ago. It is likely that they became extinct as an ultimate effect of climate change at the end of the Ice Age.

Kurten (1967) was one of the first to look at the GSFB in much detail, and he made a number of observations that have come to define this bear: shortened face like a cat, and extremely long limbs compared to body length. Kurten argued that those adaptations show a hypercarnivore, a cat-like giant predatory bear, with long runner’s legs and a bite-style like the large cats.

There is something very appealing in this picture: a huge cat-like bear running down prey and dominating the Ice Age landscape. Alas, science cannot be based on drama or romantic notions, and this image of the GSFB gets reexamined from time to time, with other authors coming to different conclusions. Some have pointed out the ambiguity of the limb proportions, or compared the GSFB to its closest living relative, the South American spectacled bear, and concluded that it was primarily omnivorous with a diet rich in plants (Emslie and Czaplewski, 1985).

The question of what the GSFBs were eating, at least, seemed to have been dramatically concluded in a couple of papers during the mid-1990s (Bocherens et al., 1995; Matheus, 1995). Those authors explored the carbon and nitrogen stable isotopes preserved in skeletal material. You are what you eat as differing amounts of these elements are deposited in body tissues depending on their dietary sources, and the isotope data clearly show that the GSFB were eating mostly meat in their diet.

In the most recent paper, Figueirido and colleagues also re-examine Kurten’s cat-like interpretations of the GSFB. For example, they challenge the very notion that the GSFB was short-faced at all. While a casual observation of the skull seems to “bear” that out, they compared the skull and face length with other bears, and it seems that what makes the skull of the GSFB look short-faced is really the depth of the snout and the height of the skull overall, creating an illusion of short-facedness.

Snout lengths relative to skull length in living bears and in the GSFB.

They also ran a number of statistical analyses on the dimensions of the skulls of bears with other carnivores to see if differences in feeding behavior might be teased out this way. Feeding strategy, such as cat-like hypercarnivory or hyena-like bone-crushing, might be visible in the skull proportions. They concluded that the GSFB had a skull shape not like that of a cat, but more similar to modern brown bears (Ursus arctos). Brown bears are omnivorous and will certainly eat meat, but also have a significant amount of plant matter in their diet. So, those authors suggest the skull shape does not support a hypercarnivorous behavior.

Figueirido et al. also examined the claim that the GSFB had extremely long legs. They compared total limb length to overall body weight among modern bears and the GSFB. Their results suggest that the limb length is just what it should be for a bear of the overall size of the GSFB, and not especially long when compared to other bears.

Nothing in science is sacred and I applaud Figueirido et al. for critically looking at past interpretations. However, the answers to our questions continue to elude us. If they are right that the GSFB was not especially short-faced, and that the limbs were not especially long, and the skull was not especially cat-like, none of that really nails down the behavior of this giant species, as they point out. And bears in particular have a tremendous range of feeding adaptations and behaviors that do not fit the mold.

For example, modern bear behavior goes from one extreme represented by the polar bear, which lives on the arctic sea ice and eats almost nothing but seals, to the giant panda living in Asian forests and eats almost nothing but bamboo (but they too will eat meat if given the chance). And between those extremes is a lot of variation. There is really no reason to think that the GSFB was not also variable in its diet and behavior to some degree. But the isotope evidence is hard to argue with at the moment: they seem to have eaten a lot of meat.

The question remains though, how did they get their meat? Did they chase down their prey in long pursuits, or ambush them from short range, or act as the neighborhood bully and chase smaller carnivores from their kills? We don’t yet know but we will keep looking.

BOCHERENS, H., S. D. EMSLIE, D. BILLIOU, AND A. MARIOTTI. 1995. Stable isotopes (C13, N15) and paleodiet of the giant short-faced bear (Arctodus simus). Comptes Rendus de l’Acadƒemie des Sciences Paris, 320, serie IIa:779-784.

EMSLIE, S. D., AND N. J. CZAPLEWSKI. 1985. A new record of giant short-faced bear, Arctodus simus, from western North America with a re-evaluation of its paleobiology. Contributions in Science, 371:1-12.

FIGUEIRIDO, B., J. A. PEREZ-CLAROS, V. TORREGROSA, A. MARTIN-SERRA, AND P. PALMQVIST. 2010. Demythologizing Arctodus simus, the ‘short-faced’ long-legged and predaceous bear that never was. Journal of Vertebrate Paleontology, 30(1):262-275.

KURTEN, B. 1967. Pleistocene bears of North America; 2. genus Arctodus, short-faced bears. Acta Zoologica Fennica, 117:1-60.

MATHEUS, P. E. 1995. Diet and co-ecology of Pleistocene short-faced bears and brown bears in eastern Beringia. Quaternary Research, 44:447-453.

Fossil ‘discovery’ rewrites history

Originally published in the Hays Daily News 21 February 2010

By MIKE CORN
mcorn@dailynews.net

For nearly 40 years, it’s been tucked away in a storage room at the University of Kansas, little more than a bag of bones that at the time it was collected struck even the most experienced as unusual.

The late Marion Bonner was right: The discovery in 1971 by his son Chuck then 21, was indeed unusual.

On Thursday, scientists announced that it was deserving of its own genus, proving to be something of a missing link between the oceans of 100 million years ago and today.

The announcement was made Thursday in Science Magazine.

The fossil, representing a massive filter-feeder much like the blue whale of today, was named Bonnerichthys, in honor of the Bonner family — responsible for outstanding fossil discoveries in the chalk bluffs of northwest Kansas.

Several of those discoveries are on display at Sternberg Museum of Natural History, as well as other museums.

The Bonnerichthys discovery came not from a recent collection, but from one that Chuck Bonner discovered in 1971 in Logan County while on a fossil-collecting expedition with his family.

“That was pretty nice,” Bonner said Friday. “Pretty nice to have a genus named after us.”

Several individual species have been named for Marion Bonner, who collected fossils alongside George Sternberg, founder of the Sternberg Museum.

While it was discovered by Chuck Bonner, the excavation work fell to his father.

“Dad knew when he was digging on it, it was something different,” Bonner said.

“I tell you what, I wasn’t too excited that day. Actually, I was more excited about Dana finding a turtle up above me.”

While the Bonner discovery — once it was cleaned up — was responsible for the naming of a new genus, there’s another and more complete specimen being prepared.

That discovery, coming from land owned by Mahlon and Carolyn Tuttle, has been donated to Sternberg and will provide even richer detail about the fish.

The Gove County specimen was discovered by Kenshu Shimada, an FHSU alumnus now at DePaul University in Chicago, and excavated by Mike Everhart, adjunct curator of paleontology at Sternberg.

Everhart has been thrilled with the credit given to the Bonner family, as well as the fossil that was collected in Gove County.

The trouble with plankton feeders is they are too much like sharks, in that they have little skeletal structure to fossilize. Much of it is cartilage and tissue.

Bones in the skull, for example, were connected by cartilage.

That made it big, but difficult to find, 100 million years later.

“It is the biggest bony fish feeding in the Cretaceous sea,” Everhart said. Generally, the Kansas variety, which makes up the largest percentage, would have been about 30 feet long.

The discovery, that it was a huge fish that fed on plankton, “filled in the blanks.”

Early on, the fish had been classed as a swordfish, but neither sword nor skull had been found.
Everhart said they have now determined that the fish lived from 170 million to 85 million years ago, dying out at the same time the dinosaurs.

“At the end of the Cretaceous, for some reason, the plankton died off,” Everhart said. That spelled doom for the filter feeders as well.

The chain of events have thrilled Everhart and Bonner.

“It’s very exciting to me,” Everhart said of the discovery and its publication in Science Magazine. “It’s not everyday you get a chance to be published in Science. It’s a pretty prestigious publication.”

Determining the fish was a filter feeder was just as significant.

“It was just an ‘aha’ moment,” he said. “We figured out what was going on.”

“He would have been swelling with pride,” Bonner said of his father.

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