Welcome back to Natural News from the Field Museum! We've got a one-armed Tyrannosaurus rex, some new research about fossil bear dogs, which are dog-like things that look like bears, and the celebration of a really weird tiny plant. Let's go!

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Sue lends a hand for science.

Sue, our iconic social media-happy Tyrannosaurus rex who boasts the title of largest and most complete representative of her species ever discovered, recently lent a hand in some new research. Literally! Her left arm was removed and taken to Argonne National Laboratory in Lamont, Illinois, where paleontologist Carmen Soriano is hoping it'll help answer one of the biggest mysteries about these animals: what did they use their impossibly small arms for anyway?

See, tiny fractures appear in bones that are used regularly. And, although they heal over time, those small breaks can tell us about the extent of how the limb functioned. Using an instrument a billion times more powerful than a regular CAT scan, Carmen will take micro CT scans of the arm in order to produce a high-resolution image of its interior. This will create a three-dimensional model so detailed, scientists will be able to examine the bone on a cellular level, illuminating microscopic details never seen before, including blood vessels in the point for muscle attachments.

Having an internal map of Sue's arm bone can tell us if she used them, and how they were used. Like, birds have hollow bones which aid in flight, and we know animals with denser bones use them for strength-based reasons. But even without looking at bone density, I'm fairly certain we can rule out Sue's flight ability using what would have been the itty-est-bitty-est little wings. Although we're at the beginning of this research, perhaps soon we will finally have an answer to the age old question: how did the T-rex use (?~1:44) use their arms? My guess: Salsa dancing.

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In 1913, graduate student Norma Pfeiffer became the youngest person ever to earn a doctorate from the University of Chicago at the age of 23. At a time before women could even vote in the United States. She had discovered a plant growing on the Chicago South Side that would soon become one of the rarest in the world: An odd translucent blue flower she described and named Thismia americana.

How she spotted it in the first place was remarkable. Norma had been crawling around on the ground collecting liverwort specimens when she saw this ethereal flower poking out of the ground only about the size of a pencil eraser. Completely struck by its weirdness, she collected a few for study and the odd plant became the subject of her graduate dissertation.

She began teaching at the University of North Dakota, but returned every summer to look for and study the rare plant. Until, in 1917, she was unable to locate it again. Over the years, a barn was erected where Thismia was last spotted, and later a factory was built on the site.

Over the course of her research, Norma realized that the reason for its blue color is that Thismia americana was completely lacking chlorophyll. Without chlorophyll it was unable to absorb energy via photosynthesis, instead relying on soil nutrients that were digested by a fungus living in its roots.

Norma also discovered that this plant's closest living relative is called the fairy lantern and is from the island of Tasmania, which begs the question: how did such a tiny plant travel halfway across the world? Later research speculated the plant could hibernate underground, making a slow and steady journey across a land bridge to end up in modern-day Illinois. But, it's a mystery we may never solve.

Dr. Pfeiffer died in 1989 at the age of 100, but neither she, nor her discovery, will be forgotten. She went on to publish 65 scientific articles primarily on lilies, eventually moving to New York with her partner Zella Colvin. During her life, she left maps and information about where she had last seen Thismia americana alive.

Today, that area is 119th and Saint Torrence Avenue in Chicago, and this year a group of Field botanist volunteers and friends made a trek out to the area in the hopes of finding another thismia flower a hundred years after it was last seen alive. The group was unable to find thismia this year, but botanists have not yet given up the hope that the weird little blue flower will still be with us, waiting beneath the surface to sprout again.

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Beardogs! They're a thing!

Field Museum's postdoctoral researcher Susumu Tomiya and colleague Jack Tseng from the State University of New York recently published two new fossil discoveries in the Royal Society of Open Science, but these weren't unearthed out in the field like many exciting museum finds. These fossils were laying in the specimen drawer for thirty years, waiting for the right person to notice their uniqueness.

What Susumu and Jack were looking at were fossil bear dogs, which  were ancient relatives of our modern-day wolves, weasels, and foxes and as the name indicates, they pretty much resemble a mashup of a bear and a dog.

Bear dogs went extinct five to ten million years ago, and the group changed a lot in the 44 million years they were around. They evolved from being small, omnivorous insect-and-fruit-eating animals to larger, more specialized meat-eaters. Paleontologists often see this trend in the fossil record.

Earlier species of a group are small, and over time get larger as they're better able to take down prey, and there are fewer competitors stealing their food. But by getting larger and limiting their food options, they can't adapt as quickly to changes in their environment, and that often leads to the extinction of a species.

While, the species Susumu came across in the collection were already known and described, he realized they've been put in the wrong part of the bear-dog tree. For example, one of the fossils was tiny, like the size of a chihuahua. Most of the bear dogs from that time originally described were larger, leading Susumu to realize the specimen was much older than first suspected.

It's like you knowing what you think is your name, and later realizing the house you grew up in with your parents isn't actually your house, and those aren't actually your parents, because your parents live on another continent, and wouldn't be alive for another fifteen million years, and also you are your parents' parents.

These newly-classified animals lived around 38-37 million years ago in what's now Texas. Now, not only do we have a better understanding of the bear-dog family tree, but we can begin understanding what sorts of animals were thriving in North America at that time. And that's another piece placed in the evolutionary tree of life.

Hey, thanks for watching this episode of Natural News from the Field Museum! This is going to be our last episode of Natural News for the year, and next week is going to be our last episode of the Brain Scoop for the year. So, we've made a lot of episodes this year. You can go back and watch some of those other ones.

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Smells like knowledge.