Past Time

Past Time is BACK! Matt and Adam have been traveling the world independently for some time, delving deeply into the history of life on the planet, but now they’re back to tell you all about what they’ve discovered!

In this episode, Matt interviews Adam about his research into the early days of the Age of Reptiles and the strange non-dinosaurs living 212 million years ago in New Mexico. Come face-to-face with Drepanosaurus, one of the strangest reptiles that ever lived on Earth, and one that has presented an anatomical mystery for over thirty years! Nicknamed “the monkey lizard,”iIt had arms like no other animal, a claw on the end of its tail, and likely lived like a modern anteater!

For more information on this project, you can check out Adam’s original article and the news article produced by Yale University!

The relationship between predator and prey is a primal one, and one that fires the curiosity of many fossil fans. We love paintings of Tyrannosaurus battling Triceratops or saber-toothed cats leaping onto the backs of ground sloths. And we can be pretty sure that those interactions happened based on TRACE FOSSILS, like tooth marks in Triceratops bones that match closely with tyrannosaur teeth. However, it’s very rare to run across fossils that preserve an animal’s meal still in its rib cage. It’s far rarer for that meal to still have IT’S last meal in IT’S STOMACH!

But that’s just the kind of fossil I talk about on Past Time today: a snake skeleton with a lizard in its stomach region, and that lizard with a partial insect still inside! I couldn’t believe the pictures when I saw them, but paleontologists Krister Smith and Augustín Scanferla have a slam-dunk case that the boa-like snake Palaeopython ate a basilisk lizard Geiseltaliellus. And, before being eaten, that lizard ate a tiny insect. That’s a whole lot of ecosystem preserved in a single fossil!

Hailing from the Messel Pit fossil site in Germany, this nearly complete snake skeleton suggests that Palaeopython ate its prey in very much the same way as modern snakes. Spectacular fossils like this can reveal amazing truths about ancient ecosystems and just how different they were from the world today!

Dig Deeper (Links and References):

For more on this discovery, check out the original research paper by Krister Smith of the Department of Palaeoanthropology and Messel Research at the Senckenberg Research Institute in Germany and Augustín Scanferla of the Instituto de Bio y Geociencias del NOA (IBIGEO) in Salta, Argentina. Read it at http://link.springer.com/article/10.1007/s12549-016-0244-1.

Past Time covered the Messel fossil site in a classic episode with Matt and Adam! Check it out at http://www.pasttime.org/2013/08/episode-6-field-guide-tiny-horses-galloping-crocs-and-fossilized-jungles/.

The Guardian newspaper reported on some of the spectacular fossils of Messel, and published some amazing photos of the crocs, birds, mammals, and insects at https://www.theguardian.com/science/gallery/2009/may/19/fossil-ida-missing-link.

And check out a much older case of a three-level trophic interaction involving a shark, amphibians, and an ancient fish at this link: 

Growth is a universal facet of all organisms that have ever lived, but figuring out how old they grow isn’t always easy. A new study examined the growth in one of the biggest predatory fish in all the ocean, the Greenland Shark (Somniosus microcephalus), revealing it to be the vertebrate species with the longest lifespan: nearly 400 years, if not more! Just goes to show that you don’t always need fossils to learn about natural history. Check it out in the latest episode of Past Time!

FURTHER READING:

Read about the original study at: http://www.sciencemag.org/news/2016/08/greenland-shark-may-live-400-years-smashing-longevity-record

More studies on growth in marine animals use bomb radiocarbon, too, including this study of the Great White.

The study linked here was the first to use this method on the age of living sharks.

For some awesome pictures of the Greenland Shark in nature, check out ARKIVE.org.

I tried to google “crocodiles are living fossils,” to see just how commonly that expression was used in popular articles. There were indeed a few articles that referenced this idea, suggesting that croc fossils from 80 million years ago would look identical the skeletons they have today. However, most were news stories reporting various discoveries in the fossil history of crocodiles and their relatives; in these, paleontologists repeatedly debunked the notion of the “living fossil,” each describing some of the strange twists and weird turns taken by crocs over the past 250 million years.

I wouldn’t argue that croc history is fraught with more twists than an M. Night Shymalan movie, but there’s ONE place where I think the “living fossil” statement can be used. The body plan of crocodiles, the overall construction of the various parts of the animal, has been maintained for at least 190 million years since the Jurassic Period. The long, flat snout; the low slung body with a sprawled posture; and the coat of armor have held true for all that time. Now, as I note in the episode, the individual species and families of crocodile-relatives that have explored this sit-and-wait aquatic ambush predator role have varied greatly through time. There is a constant pattern of competition, extinction, and dynamic change in the fossil record. But, if we are to use “living fossil” to describe the basic “shape” of the modern croc, I think that is pretty appropriate.

The creatures featured in this episode of Past Time are members of the extinct croc-relative family Allodaposuchidae: the short-snouted, big-toothed Lohuecosuchus and the alligator-like Agaresuchus. These two animals co-existed in a single ecosystem in the Late Cretaceous Period of Spain. As illustrated above by Carlos de Miguel (deviant art link below), the two were roughly the same size despite their dramatic differences in anatomy. It is unlikely that these two aquatic predators did not occasionally come to blows (bites?) over the body of a hapless dinosaur plucked from the riverbank. But, we know from today’s crocodile-dominated regions that multiple croc species can coexist just fine, suggesting that they don’t completely overlap in their ecological roles. The major anatomical differences between the new species suggests t