The Tully Monster: Illinois' Oldest Mystery

Illinois’ state fossil is bizarre … so bizarre that it took scientists decades to figure out its place in the animal kingdom.

Illinois’ state fossil is the Tully monster, perhaps the weirdest animals ever to have existed on earth!

THIS WEEK IS ILLINOIS FOSSIL WEEK AT NATURAL CURIOS. OVER THE NEXT FEW DAYS, YOU’LL MEET ONE OF THE STRANGEST CREATURES TO EVER EVOLVE, GIANT, SHAGGY ELEPHANT-LIKE ANIMALS THAT ONCE STOMPED ACROSS THE STATE AND INSPIRED THOMAS JEFFERSON, AND SOME OF THE LARGEST FOSSILS IN THE WORLD THAT CURRENTLY RESIDE AT CHICAGO’S FIELD MUSEUM.

In a primordial tropical swamp, an alien monster slices through the warm water. Its eyes extend from the side of its streamlined body on long, rigid eye stalks. The creature’s mouth, studded with eight sharp teeth, is extended on a long proboscis in front of the head. It is both the first thing and the last thing this monster’s prey will ever see. 

This may sound like it is taking place on Mars or one of Jupiter’s moons, but this creature once haunted Northeastern Illinois some 300 million years ago. Moreover, this creepy monster straight from the pages of a science fiction novel only maxed out at 14 inches long. Even if you fell through a time portal and landed in Grundy County, Illinois during the Pennsylvanian period, you would not have to fear the Tully monster (Tullimonstrum gregarium).

The Tully monster needs its turn on the big screen as it chases incredibly tiny time travelers through the swamps of primeval Illinois.

But if you were dropped into the Tully monster’s realm, you would indeed be in another world. During the aforementioned Pennsylvanian period, Illinois was right on the equator, smushed in the middle of the supercontinent Pangea. Much of Illinois was covered by dense forests and swamps full of primitive and strange plants that were eventually compressed into the coal we extract from Illinois today. Mazon Creek, an area known for its treasure trove of fossils from this time period, looked similar to the delta of the Amazon River. Rivers carrying the dead remnants of plants and small animals washed into the ocean here. A few pieces of this organic material sank into the muddy seafloor fossilized, eventually becoming vestiges to the deep past. 

Some of these creatures serve to fill in the gaps in the evolutionary tale of the planet. Early jellyfish, squid, shrimp and even sharks are found here, providing insight into how these groups of animals have evolved over time. The Tully monster is not so helpful. Instead of illuminating secrets from this tropical, ancient Illinois, the bizarre creature only confused scientists, eluding placement in the tree of life for over sixty years. Thus, the Tully monster became an enigma trapped inside the nodule rocks of Mazon Creek, almost taunting frustrated scientists. 

The Tully monster takes its name from its discoverer, Francis Tully, who discovered it in the late 1950s while fossil hunting near a coal mine. The bewildered scientists at the Field Museum, where Tully took his unusual discovery, dubbed it “Mr. Tully’s Monster” to highlight the pint-sized creature’s strange appearance. Being unique to Illinois, as well as extraordinarily weird, the Tully monster became Illinois’ state fossil in 1989 even though no one really knew what it was although theories abounded.  Some scientists thought it was a segmented worms, while others thought it was a primitive marine slug. Most people could only agree on the fact that the Tully monster was an invertebrate. It had to be, right? Not quite. 

A collection of Tully monsters at the Field Museum of Natural History in Chicago.

After painstakingly analyzing over 1,200 Tully monster specimens, researchers led by Victoria McCoy of the University of Leicester, who partnered with the Field Museum in Chicago, found evidence of a notochord in the enigmatic marine creature in 2016. A notochord, seen as a faint, thin line running from the creature’s snout to the tip of its tail, is a primitive structure that eventually gave rise to the spinal cord in all vertebrates, including us. It turns out the Tully monster was not a worm, or a slug, or even an invertebrate. It was one of the oldest vertebrates, finally taking its rightful place on our side of the tree of life. 

McCoy’s study classifies the Tully monster in a group of jawless fish that gave rise to lampreys, who are still around in rivers today, sucking blood from unsuspecting fish with their toothy suction-cup of a mouth. Lampreys are one of the most primitive creatures with a backbone, and we now know that they came from ancient fish like the Tully monster. 

With one of paleontology’s biggest mysteries solved and the Tully monster’s identity finally understood after sixty years, much still needs to be understood about the incredible creature. How did it eat and traverse its muddy environment? How did it even swim? Although some of the enigmatic creature’s mystery has been put to rest, there is still an incredible amount of questions trapped in the ancient rocks at Mazon Creek.

All artwork and photography by Jack Tamisiea.

Sources:

https://www.isgs.illinois.edu/outreach/geology-resources/illinois-state-fossil-tullimonstrum-gregarium

https://www.nature.com/articles/nature16992

https://news.nationalgeographic.com/2016/03/160316-tully-monster-vertebrate-fossil-animal-paleontology-science/

https://www.scientificamerican.com/article/tully-monster-mystery-solved-scientists-say/

http://isgs.illinois.edu/outreach/geology-resources/pennsylvanian-rocks-illinois

https://www.fieldmuseum.org/node/5126

https://naturalhistory2.si.edu/paleobiology/mazoncreek/

The Mastodon: Illinois' Patriotic Proboscideans

Illinois was once home to the shaggy, elephant-like mastodon, whose monstrous size gave America and a founding father pride in the young country’s natural history.

Illinois’ state flag with a prehistoric twist.

THIS WEEK IS ILLINOIS FOSSIL WEEK ON NATURAL CURIOS. OVER THE NEXT FEW DAYS, YOU’LL MEET ONE OF THE STRANGEST CREATURES TO EVER EVOLVE, GIANT, SHAGGY ELEPHANT-LIKE ANIMALS THAT ONCE STOMPED ACROSS THE STATE AND INSPIRED THOMAS JEFFERSON, AND SOME OF THE LARGEST FOSSILS IN THE WORLD THAT CURRENTLY RESIDE AT CHICAGO’S FIELD MUSEUM.

Illinois’ contemporary wildlife is relatively paltry in comparison to its storied past. Bison, elk and mountain lions have been erased from the Land of Lincoln for a century. Black bears used to be plentiful throughout the state until 1870.  Since 2008, there have only been three black bear sightings in Illinois. Today the largest animals you will see are white-tailed deer and coyotes.

But not too far in the past, giants lumbered through the ancient forests of modern-day Illinois. Around the size of an African elephant, the mastodon was a hulking browser with long, straight tusks and a flatter skull than its modern, distant relatives. The American mastodon (Mammut americanum) roamed Illinois and the rest of the Eastern United States from 3.75 million years ago to around 10,000 years ago, recent enough to inspire Native American legends of immense beasts bulldozing their way through the forest.

The Field Museum’s mastodon skeleton.

The creature’s colossal remains also captured the imagination of early European settlers to the United States. A massive mastodon tooth was discovered in New York in 1705. The tooth was eventually transported to London and rightfully labeled as a tooth from a “giant”. The fearsome creature that the gargantuan tooth belonged to became known as the incognito, or unknown animal, and was thought to be 70 feet tall by some sources. Although it may seem silly today, the creature’s incredible actual size (only 10 feet tall at the shoulder) became a sense of extreme national pride, especially to America’s third president.

For years Thomas Jefferson engaged in a bitter debate with the French naturalist, Georges-Louis Leclerc, over which continent had the bigger animals. Leclerc claimed that geographical factors in North America caused the North American animals to become “degenerate” compared to the elephants and lions of the old country. Jefferson was so incensed by the naturalist’s disparaging view of his country’s wildlife that he went so far as to transport large mountain lion skins and moose remains across the ocean to rub in the French naturalist’s  face during his visits to Paris. But the creature that Jefferson had been waiting for, the one that would come to symbolize America’s natural exceptionalism in the country’s early years, was the mastodon.

The mastodon skeleton from the Field Museum’s Evolving Planet. Mastodon tusks are actually extremely modified upper incisor teeth.

In 1801, Jefferson helped painter-turned-naturalist, Charles Wilson Peale, exhume a massive skeleton from the Hudson River Valley in New York. The creature, whose skeleton remains were embellished with extra bones and fake materials by Peale, was eventually the star attraction at his museum in Philadelphia, the nation’s first natural history museum. This turned out to be only the second fossil reconstruction display in history, and it showed --- when first pieced together, the animal’s tusks were erroneously attached upside down.

Jefferson, who claims to have eventually convinced Leclerc to abandon his theory of degenerate species found in the new world, was not content with one mastodon. He would lay out the creature’s massive bones in a room in the White House, taking in its magnificent size. He even believed that the gargantuan creatures still roamed somewhere in the mysterious expanse of land to the west. When he sent Lewis and Clark out to explore the recently acquired land from the Louisiana Purchase in 1804, he desperately hoped they would discover the creatures still roaming in some pristine forest beyond where the map ended.

In Illinois, mastodons overlapped with their slightly larger cousins, the mammoth. When their huge bones became exposed (due to the process of erosion) starting in the 18th century, the two creatures were assumed to be the same until someone compared the teeth. Mammoth teeth are flat with small ridges, perfect for grinding grass and very similar to the teeth of their modern cousin, the elephant. The distantly-related mastodon had large cusps with sharp ridges, teeth so bizarre that some early scientists labeled them as carnivores. Their teeth proved to be perfect for stripping leaves from tree branches snagged with the mastodon’s trunk.

It’s all in the teeth: mastodon teeth (far left) look completely different than the distantly related Asian elephant (middle) and woolly mammoth (right). Despite the animals’ similar appearance, they had much different diets as illustrated by their different teeth.

Because the two giants had different diets and lived in different environments, they were able to coexist in some areas like Illinois. In Illinois there have been around 80 sites where mastodons have been found and close to 60 for mammoths. Many of these otherworldly remains are exposed at construction sites near Chicago as the city continues to expand. An almost complete mastodon jaw, studded with its tell-tale teeth, was uncovered in Bolingbrook during construction of the Interstate 55 highway. Two mammoth tusks were found in a creek in Logan County in 2005. Just this past April, a tusk, part of a jaw (complete with teeth) and massive leg bones from a mastodon were uncovered as workers tried to install a sewer line in Seymour, Indiana. The animal’s spectacular skeleton has graced some of the biggest stages in Illinois’ illustrious history, including Chicago’s Columbian World Fair in 1893, where it took its place of honor alongside the first Ferris wheel and specimens from every corner of the globe.

A nearly complete lower mastodon jaw discovered in Bolingbrook, Illinois at the Field Museum of Natural History.

Both of these titans from the Ice Age disappeared across the country at around the same time, between 11,000 and 10,000 years ago. There has not been one “smoking-gun” factor responsible for their extinction. The most likely explanation is that a variety of factors contributed to their demise, from a warming climate to the arrival of humans from Asia who brought spears and diseases with them. Whatever the cause, mastodons and mammoths, along with the American lion, giant ground sloth, and saber-tooth cats, stood no chance and faded into extinction, leaving only massive bones  behind as proof of their time spent roaming the fertile lands of the Midwest.

In Illinois circa 2019, it takes quite a bit of imagination to picture the venerable creatures of the state’s past. Places like the Field Museum serve as a catalyst to help the young and old alike imagine a more primeval Illinois, one where a massive mastodon lumbered out of the dense thicket surrounding a swamp, grinding a trunk-full of leaves with its cusped teeth while great herds of mammoths trudge along the plains in the distance.

Me holding a cast of the enormous tooth from a mastodon!

Related Articles:

All photos and art by Jack Tamisiea.

Sources:

https://www.smithsonianmag.com/science-nature/mammoths-and-mastodons-all-american-monsters-8898672/

https://www.foxnews.com/story/mastodon-remains-turn-up-in-illinois

https://abc7chicago.com/science/mastodon-bones-unearthed-on-southern-indiana-farm/5263190/

https://www.huffpost.com/entry/9-illinois-critters-that_b_7787342

Fantastic Fossils in the Field

Chicago’s Field Museum has assembled an impressive (and imposing!) collection of fossils, emphasizing the incredible scale of prehistory. Among the most coveted in the collection are the largest creatures to ever walk, fly and feast on other dinosaurs!

SUE’s incredible skeleton is bathed in light at the Field Museum of Natural History in Chicago.

This week is Illinois Fossil Week on Natural Curios. Over the next few days, you’ll meet one of the strangest creatures to ever evolve, giant, shaggy elephant-like animals that once stomped across the state and inspired Thomas Jefferson, and some of the largest fossils in the world that currently reside at Chicago’s Field Museum.

For the Field Museum’s 125th anniversary this past year, the museum’s Stanley Field Hall was revitalized, once again, with the help of some of the largest creatures in the history of life on earth. This main foyer, a grand neoclassical hall on par with many of the immense exhibition halls from Chicago’s World Fair of 1893, is the perfect place to display these incredibly large specimens for the world to see. Towards one end of the hall are two enormous totem poles, seemingly reaching for the hall’s windowed ceiling and blue sky beyond. Close by, two bull elephants, posed by the pioneer taxidermist Carl Akeley all the way back in 1909, appear to be jostling each other for the prime position atop the display’s podium. These two displays, however, are somehow dwarfed by the newest additions to the hall.

Carl Akeley’s Fighting African Elephants.

Gone from the main hall is SUE, the world’s largest and most complete Tyrannosaurus rex skeleton discovered (more on her, or it, later). In its spot is the only fossil capable of making the world-famous T. rex skeleton look tiny in comparison. Maximo, the Patagotitan mayorum skeleton cast, is 122 feet long and 28 feet tall, weighing in at over 70 tons when alive. That’s almost as much as 12 of the fighting elephants off to Maximo’s side! From the tip of the tail all the way to the animal’s nose, situated so the dinosaur is looking eye-to-eye with guests on the hall’s second level, the creature’s length eclipses SUE’s length by some 80 feet!

Hi There! The iconic giant dinosaur’s head greets visitor on the museum’s second floor.

Patagotitan mayorum is considered to be the biggest dinosaur ever, making it also the largest terrestrial animal to ever walk on earth. Discovered in Argentina in 2012, the gargantuan sauropod belonged to the largest group of dinosaurs in history, the aptly named titanosaurs. It is not known how these behemoths grew so big, but it is worth noting that their evolutionary growth spurt coincides with the emergence of flowering plants in the Cretaceous Period for the lumbering vegetarians to dine upon.

Maximo even makes the largest living land animals look tiny by comparison!

Above the staggering cast of the titanosaur, the largest animal to walk, soars the largest animal to ever fly, Quetzalcoatlus northropi. Named after the Aztecs’ feathered serpent god, the pterosaur is just as grand: when standing it was as tall as a giraffe! The Field Museum has two life-size replicas, one of which is soaring over Stanley Field Hall, displaying every inch of its 33-foot wingspan. Quetzalcoatlus was part of an unusual group of jumbo-pterosaurs that took to the sky during the Late Cretaceous Period. The immense size of these pterosaurs inhibited them from rapidly flapping their wings once airborne, which forced them to glide on hot air currents. Once airborne, the titans of the sky could fly for almost 10,000 miles (at speeds up to 80 mph) nonstop according to some pterosaur scientists!

Quetzalcoatlus sported a wingspan as wide as some early airplanes!

But propelling such a large body into the air was no small task. The animal probably jumped off of all four limbs, like some bats do. Although huge, its bones were hollow, making the skeleton a relatively lightweight 550ish pounds (still by far and away the heaviest animal to ever fly). However, Quetzalcoatlus’ fossils point to the animal being just as comfortable on land, where it could hunt smaller animals in a similar manner to how storks hunt today. The animal greedily gobbled up baby dinosaurs with its 6-foot long jaws. Its remarkably long neck allowed its mouth to reach prey quickly, thus maximizing the element of surprise on unsuspecting prey.

Quetzalcoatlus was still a behemoth while on the ground, as evidenced by how it towers over me.

Quetzalcoatlus is not the only thing flying through Stanley Field Hall. Two imposing Pteranodon models, with 18-foot wingspans each, hang over head as one mounts the stairs toward the Griffin Halls of Evolving Planet exhibit. The giant, toothless (similar to Quetzalcoatlus) monsters would have been a common site soaring through the Late Cretaceous skies in the western United States. A third species suspended above the hall is Rhamphorhynchus, the smallest and oldest of the bunch. But these little guys sported mouths full of razor-sharp teeth to snare fish in the Late Jurassic Period (some 160 million years ago). The hawk-size pterosaur was discovered in 1825 in Germany, relatively early on in paleontology’s history. In all, nine of the toothy, pint-sized terrors are on display in Stanley Field Hall.

Upon following the lead of the soaring pterosaurs, you will arrive at the aforementioned Griffin Halls of Evolving Planet exhibit halls, where you can trace evolution throughout the 4 billion years of earth’s history with the help of some stunning fossils. If you are still clamoring for size, these halls have you covered. The fearsome armored head of the first huge super-predator, Dunkleosteus, greets you around one corner. A mammoth, 72-foot Apatosaurus excelsus skeleton, just about the biggest skeleton one would see outside of Maximo, takes center stage in this main dinosaur hall.  Finally, one of my favorite skeletons in the entire museum is the 12-foot tall skeleton of the giant short-faced bear (Arctodus simus). The monster bear’s long legs made it capable of running over 40 mph…at 1,500 pounds! Its short face was anchored by strong, vise-like jaw muscles that made it the apex predator in an ecosystem with saber-tooth cats, giant wolves and lions.

The giant short-faced bear roamed the western United States during the last ice age.

But the star of the Field’s sublime paleontology collection still has to be SUE, possibly the most spectacular fossil ever discovered. After relinquishing her old stomping grounds to Maximo, the tyrannosaur actually upgraded to a shiny new penthouse-like hall just off of the dinosaur hall. The individual space offers the museum a better opportunity for telling SUE’s story, from its discovery by Sue Hendrickson in 1990, to the groundbreaking science its fossils continue to provide today.

SUE gets its rightful spot in the spotlight.

Most people are confused about why SUE is referred to as ‘it’ since Sue is a female name, after all. In reality, the 65 million years that have elapsed since SUE was buried in sediment make it is impossible to determine the animal’s sex. The creature simply takes its nickname from its discoverer, Sue Hendrickson.

One of my favorite paintings I’ve done stars the world-famous T. rex.

The new dedicated space also allows the skeleton to look bigger…much bigger. You feel every inch of its 40 feet and see every one of its banana-sized teeth. Out ahead of the spectacular skeleton, which is 90% complete, is the tyrannosaur’s skull. Upon closer inspection, the giant cranium looks unbelievably heavy and slightly deformed due to the eons it spent buried in the ground. The exhibit also tells the story of the environment SUE lived in, as well as the animals on the menu (including its famous foe, Triceratops). SUE needed its own space to truly tell its story and continue to rightfully stir our collective imagination.

SUE’s actual skull, though slightly deformed by the fossilization process, still fuels nightmares thanks to that fearsome maw.

The Field Museum is one of the preeminent paleontology institutions in the world, and its latest commitment to displaying these ‘giants’ only doubles-down on the museum’s storied journey over the past 125 years. In 1894, Chicago needed a museum to house all of the specimens procured during the Columbian World Fair of 1893, and The Field Museum emerged. Some of earliest specimens were the giant trunk from a California redwood tree and the large skeleton of a mastodon. Over the next century and change, the museum has continued to collect and emphasize specimens of both great size and great scientific value to the delight of scientists and visitors alike.

Stanley Field Hall offers the perfect habitat for giants at Chicago’s Field Museum!

All art and photography by Jack Tamisiea.

Sources:

https://bear.org/the-giant-short-faced-bear/

https://www.fieldmuseum.org/blog/meet-sues-new-neighbors-hall-dinosaurs

https://www.fieldmuseum.org/blog/meet-pterosaur-flock

https://www.wired.com/2013/11/absurd-creature-of-the-week-quetz/

https://phys.org/news/2017-08-patagotitan-mayorum-biggest-dinosaur.html

https://www.fieldmuseum.org/about/history

https://www.chicagotribune.com/data/ct-maximo-dinosaur-field-museum-20180606-htmlstory.html