Past Time

This episode was a blast to produce for a vertebrate scientist. I learned a ton about the echinoderms, the group of invertebrate animals to which sea stars, brittle stars, sea cucumbers, sea urchins, and crinoids belong. Be prepared for more adventures with invertebrate animals in the future.

This episode would not have happened with Elizabeth Clark, graduate student in the Geology Department at Yale University and my gateway to echinoderms. As a part of the lab of Derek Briggs, Liz has studied a wide range of topics on echinoderm paleontology and biology. You can check out the original scientific paper on her Ordovician asteroid in Biology Letters and the Yale News story about the discovery. The original specimen of Protasterina flexuosa featured in the study is pictured below. It actually lived alongside the Flexicalymene trilobites featured in our previous invertebrate episode. You can see their fossils (and hundreds of thousands of others) at the Cincinnati Museum Center in Cincinnati, Ohio.

I had a lot of fun watching echinoderms locomote while making this podcast. I really cannot believe the diversity of movement styles they adopted throughout their history. A lot of this system is built on the water vascular system and associated tube feet, but many species explore different methods for motion. Check ‘em out below!

Matheronodon is certainly a dinosaur worthy of a bigger bite. With proportionally giant teeth strikingly different from the standard-issue ornithopod dinosaur, it is certainly one of the most important dino discoveries out of Europe this year. Better yet, the original scientific paper by Pascal Godefroit and colleagues is free to read in the journal Scientific Reports! If you’d like to learn more about Rhabdodontidae, the small but successful family of dinosaurs to which Matheronodon belongs, check out the papers in the reference list below.

The original specimen (pictured below) is housed at the Musée du Moulin Seigneurial in Velaux, France. I looked up the museum online, and it looks really cool. Built in an old olive mill, the exhibits include Cretaceous in Provence displays. The displays include specimens of Matheronodon contemporaries, including the sauropod Atsinganosaurus velauciensis, the crocodile Allodaposuchus, and ancient turtles. If I get a chance to visit, I’m hoping the Matheronodon teeth and jaws will be there too!

Our guest this episode was Dr. Ali Nabavizadeh, who was not actually involved in the study. But, he is one of the most knowledgable scientists working on dinosaur jaws! His work focuses on the evolution of eating in herbivorous animals. His early work focused entirely on dinosaurs, but he has branched out into other plant-eating reptiles and mammals. Ali’s work was featured on a classic episode of Past Time on j

The quest to recover ancient genetic material from extinct animals had its blockbuster moment when Jurassic Park came out. But where did the idea come from and who is trying to figure out if the science fiction of Jurassic Park can be science reality? We talk to Dr. Elizabeth Jones, a science historian at University College London, about her work digging through the murky early history of ancient DNA and the dynamic scientists who are trying to figure out how fossils sometimes preserve more than bone.

One of Dr. Jones’s amazing contributions to the history of science is her work interviewing the people who have been thinking about and trying to recover ancient DNA. As a historian of science, she can put look at larger trends in how ideas get passed around between scientists, and how media and public interest affects the scientific process.

One key distinction to remember is there is a difference between researchers who are interested in recovering ancient DNA to study what it might tell us about ancient populations or the relationships of ancient animals to modern animals. There’s a whole separate field of researchers who are trying to figure out how to resurrect extinct animals using ancient DNA and cloning technology. These fields feed interest in each other, but they involve different techniques, different philosophical questions, and different research questions.

Dr. Jones calls Ancient DNA research a “celebrity science” because each new revelation gets tons of media attention. Listen to our discussion to learn more about where the field started and what might be on the horizon!

An article summarizing all the amazing insights Neanderthal DNA has revealed:

https://www.theverge.com/2017/10/9/16448412/neanderthal-stone-age-human-genes-dna-schizophrenia-cholesterol-hair-skin-loneliness

An article covering Dr. Mary Schweitzer’s work on dinosaur proteins:

http://www.sciencemag.org/news/2017/09/i-don-t-care-what-they-say-about-me-paleontologist-stares-down-critics-her-hunt

Hi all. Adam Pritchard here.

I’ve been thinking about telling the story of my field experience in the Triassic-aged Chinle Formation of northern New Mexico for many years. The Hayden Quarry fossil site at Ghost Ranch has produced the best-preserved and most diverse record of American dinosaurs from the Triassic of North America, plus some of the strangest reptiles that ever lived. I’ve been proud to be a part of the Ghost Ranch field crew for nearly a decade now!

First off, here are some links to exhibits and museum experiences relating to the Ghost Ranch project, including the recent Hayden Quarry discoveries:

The Ruth Hall Museum of Paleontology at Ghost Ranch

Paleontology at Ghost Ranch Jan-Term courses

Shelf Life episode about the Ghost Ranch area and dinosaur evolution.

I thought it’d also be good to add some links to the MANY books scientific

A few weeks ago Past Time co-host Matt Borths published a study that identified a new species of now-extinct carnivorous mammal from Egypt. The animal was near the top of the African food chain when Africa was cut off from the other continents. It lived in the same swampy ecosystem that was home to our earliest monkey-like relatives!

Here’s a link to the original paper in the open access journal PLOS ONE <http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0173527> if you want to take a look at the original fossils. You can even see them in 3D at www.morphosource.org

Masrasector means “The Egyptian slicer” because the meat-eater was found in the deserts of Egypt, near the Fayum Oasis southwest of Cairo. The species name, nananubis, means “tiny Anubis,” because the small, fox-sized carnivore resembles the jackal-headed Ancient Egyptian god of embalming and guide through the afterlife. “Tiny Anubis” likely scrambled on the ground, chasing large rodents and small hyraxes through the Fayum wetland. It probably didn’t spend a lot of time weighing the hearts of the dead, but such behaviors don’t fossilize very well.

Masrasector nananubis was part of an extinct group of carnivorous mammals called hyaenodonts. If you think of a meat-eating mammal today, like a wolf, tiger, or hyena, you’re thinking of a species from the mammalian order Carnivora. Carnivorans are united by having one pair of specialized meat-slicing teeth on each side of their face. Next time you see a dog or cat yawn, look in the back of their mouth for the scissor-like blades. Hyaenodonts had three pairs of these meat-slicers on each side of their mouths instead of just one, making it easy to recognize them in the fossil record. Hyaenodonts were the only meat-eating mammals in Africa for over forty million years between the extinction of the dinosaurs and the arrival of the first African carnivorans.

Carnivorous mammals are rare in modern ecosystems, and this was also true in the past. Fossilization itself is a rare event, which means the chances of a rare carnivore becoming a rare fossil are very low. This means African hyaenodonts are a rare find, and most are only known from a few isolated teeth and jaws. But, Masrasector is known from several nearly complete skulls, dozens of jaws, and pieces of arm bone.

With all this material it’s possible to really dig into what Masrasector ate, and how it moved through its environment. African carnivores like lions and hyenas are fascinating, endangered creatures. Hyaenodonts were a separate experiment in how to be a carnivorous African mammal, and they did it successfully for millions of years.Masrasector offers a detailed view of how African hyaenodonts pursued their prey and what their diet was like.

The specimens were discovered in a quarry called Locality-41, one of the most fossil-rich places from the beginning of the Age of M