Past Time

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Episode 11: Trilobites and the Cincinnati Sea Apr 11, 2014

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Over 400 million years ago the oceans were teeming with life, but it didn’t look much like what you see at the aquarium or in Finding Nemo. Instead of colorful fish flitting through coral reefs, the ancient seas had giant, shelled squids darting past the icons of the early ocean: The Trilobites! Journey back to the Late Ordovician sea with Dr. Brenda Hunda, Curator of Invertebrates at the Cincinnati Museum Center. Dr. Hunda has spent her career carefully documenting the changes in trilobites in the remarkable rocks near Cincinnati, Ohio. Trilobites were spectacularly diverse early arthropods (the group that includes crustaceous, insects, and arachnids) that adapted to the ever-changing seas, by swimming through the water, scooting along the ocean floor, and burrowing through the mud for their 300 million year reign. Our journey through the ancient Queen City features the musical talents of two great Cincinnati-area bands: The Cincinnati Dancing Pigs and Jake Speed and the Freddies! Take the plunge into invertebrate paleontology with Matt and Adam in this episode of Past Time!

Quick Bite: From Terror Bird to Gentle Giant Mar 10, 2014

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50 million-years ago, the heir to Tyrannosaurus stalked the forests of ancient Europe and North America, snapping up the tiny ancestors of horses, cows, and wolves in its colossal meat-cleaving beak. Gastornis was a six-foot-tall, flightless bird and the king of the food chain...or that’s what we thought. For decades paleontologists looked at the huge, parrot-like head and thought the giant bird must be a carnivore, but a recent, exhaustive study drew on molecular evidence, anatomical evidence, and ecological evidence to show Gastornis was a giant herbivore! The former terror bird likely used that massive beak to crack open the abundant seeds and leaves that would have littered the forest at the beginning of the Age of Mammals. Tune in to Past Time to learn how the fossil Terror Bird became Big Bird!

Quick Bite: The Alien Turtle and Ancient Color Feb 01, 2014

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Meet Alienochelys selloumi, a giant, snorkel-nosed turtle with powerful, shell-crushing plates in its massive beak! The distant relative of the largest turtle alive today, the leatherback sea turtle, Alienochelys swam the ancient ocean of North Africa at the very end of the Age of Dinosaurs (the Late Cretaceous). It was found in the same rocks as Ocepechelon, the whale turtle discussed in our first Quick Bite back in July. There were a lot of giant, goofy, snorkel-snouted turtles in Cretaceous Morocco! When Alienochelys' discovery was announced, another paper was published describing fossilized pigment molecules that showed many marine reptiles, including a 55 million-year-old leatherback sea turtle, were dark in color, an adaptation we see in many modern swimming vertebrates. It's time to pick a new-favorite fossil turtle with Past Time!

Episode 10: The Hobbit – An Unexpected Discovery Jan 19, 2014

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Little people! Giant reptiles! Towering elephants! Huge birds! It sounds like the stuff of literary and box-office gold, but this Middle-Earth-like world actually existed 17,000 years ago on Flores, an island near Indonesia. Homo floresiensis, or "The Hobbts", only stood three feet tall but they cast a huge shadow over the story of human evolution. In 2004 fossils of the small, big-footed hominins were discovered and they have challenged paleoanthropologists, like this episode's Dr. William Jungers, to reconsider many hypotheses of human origins including which species left the continent and how we're all related. Once thought to just be small versions of Homo erectus, the hobbits may have much more ancient ancestors, posing more questions for the fossil record to answer as the human story becomes even more complicated...and interesting!

Quick Bite: The Giant Before the Tyrant! Dec 01, 2013

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Last episode we featured Lythronax, the oldest-known North American tyrannosaur and a close relative of Tyrannosaurus rex. But tyrannosaurs weren’t the only big carnivores to tromp through the Mesozoic of North America. Before the tyrant lizards were huge, there was another giant terrorizing the American West: Siats! Named for a Ute mythological giant, Siats was a bus-sized carnivore in the middle Cretaceous of Utah (99 million years ago). The giant had close relatives - the neoventors - on almost all the continents. This is a bit of a mystery because the continents were getting spread out by 99 million years, making it tough to explain how the neovenators conquered the world. In North America, this global dynasty replaced another family of giants: the carcharodontosaurs which included Acrocanthosaurus the top carnivore of the Early Cretaceous of Western and Eastern North America. The discovery of Siats shows different lineages of carnivorous dinosaurs could get really big and T. rex is just the last monarch to fill the giant carnivore niche in North America. It’s another toothy, terrifying tale on Past Time!

Episode 9: New Relatives of Tyrannosaurus rex! Nov 06, 2013

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Tyrannosaurus rex is a dinosaur celebrity, a villain in most dinosaur movies and documentaries, but where did the massive beast come from? On November 6, 2013, a team of paleontologists including our expert in this episode, Dr. Randy Irmis from the University of Utah and the Natural History Museum of Utah, published two new skeletons of Tyrannosaurus’s close kin: Teratophoneus and Lythronax. The skeletons reveal Tyrannosauridae (T. rex’s family) was diverse 80 million years ago with different species living in different parts of Western North America. The new genus Lythronax is the oldest member of the Tyrannosauridae even though its anatomy closely resembles the last species of tyrannosaurid, T. rex. A massive sea divided Western North America, called Laramidia, from Eastern North America, called Appalachia. Laramidia was a long, skinny continent that ran from Alaska to Baja California. In general, in modern ecosystems, the larger the land-mass, the more species can live on it. Laramidia was one-tenth the size of the continent of North America, but it supported more species of large animals than the complete continent of North America today! Geologists, paleontologists, and ecologists aren’t sure how this was possible so they continue to search for new fossils and the origins of the North American ecosystem. New fossils, like Teratophoneus and Lythronax show us there are still more questions to answer using the fossil record! Sic semper tyrannis!

Episode 8: Crocodiles are the Chomping Champions Oct 29, 2013

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Fossils are the raw materials of paleontology, but if we want to know how an animal moved or ate, paleontologists, like Dr. Paul Gignac, need to study living animals, too. Dr. Gignac studies crocodylians, measuring their bite forces across species and as they grow up to figure out how the strongest bite in nature evolved. Using techniques drawn from mechanical engineering and physiology, Dr. Gignac discovered the relationship between body size and bite force in crocodiles, and developed equations to calculate those forces. Then he used these equations to calculate the bite forces of giant extinct crocodiles like Deinosuchus. He also studied the bite marks left by the sickle-clawed dinosaur Deinonychus to calculate dinosaur bite forces. There are so many questions to ask about extinct animals but there's also a lot left to learn about their living descendants! The lines between scientific disciplines get blurred and the questions just get more interesting in this episode of Past Time!

Episode 7: Walking through Whale Evolution Oct 08, 2013

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Whales are spectacularly specialized mammals that seem perfectly adapted to their marine habitat. Plenty of other mammals have gone back to the water, but whales take it to a whole new level. No back legs, weird ear bones, noses on top of the head. What could the land-based ancestor of whales possibly looked like? Is there a fossil record of walking whales? In this episode we discover whales belong to the hooved animal group called Artiodactlys and their closest relatives, according to molecular comparisons, are hippos! But hippos and extinct fossil whales don't look very much alike. How did paleontologists, like our guest Dr. Marueen O'Leary, figure out the origins of whales, and how will they figure out the origins of hippos? As always, there are always more questions to answer when we start digging into the fossil record!

Quick Bite: New Mammals from the Age of Dinosaurs! Sep 05, 2013

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Mammals were scrambling around during the Age of Dinosaurs and they're usually seen as small, shrew-like animals waiting for their chance to become diverse. But recent research, including three new fossils discovered in 160 million-year-old rocks from China, show our mammalian cousins were ecologically specialized creatures. Arboroharamiya was climbing through the trees while Megaconus scrambled along the ground, and Rugosodon lead the way for the diverse radiation of mammals called Multituberculates. In this episode, Matt tries to show Adam why these new, tiny mammals are so interesting and where they fit into the mammalian tree of life.

Episode 6: Tiny Horses, Galloping Crocs, and Fossilized Jungles! Aug 16, 2013

Show notes

The fossil record is pretty patchy. Most discoveries are tooth fragments, chunks of shell, or isolated slivers of bone and paleontologists are trained to eke out as much information from these precious fragments as they can. But some fossil deposits preserve more than just bones and teeth. Called "Lagerstätte" some rare deposites preserve traces of difficult-to-fossilized soft-tissues like feathers and fur. Some even preserve an animal's last meal before it entered the fossil record. In this episode of Past Time, Matt and Adam discuss Messel, a German fossil site that is one of the best examples of the biological and ecological knowledge preserved in these rare Lagerstätten deposits. Early bats, mini horses, and galloping crocodiles once roamed this extinct jungle in the heart of Europe. The exquisite preservation at Messel lets paleontologists travel back to this exotic ecosystem to tease out connections between the beginning of the Age of Mammals and modern tropical environments.

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