trilobite

Texas State University’s Shelly Wernette, Ph.D., a senior lecturer in the Department of Geography and Environmental Studies, joins the Big Ideas TXST podcast to discuss her discovery of 10 new species of extinct trilobites in Thailand and what those discoveries reveal about ancient world geography.

Trilobites are extinct sea creatures that rolled up like some types of armadillos or rolly pollies and breathed through their legs. Fossils of the creatures were trapped in sandstone between layers of petrified ash, created by volcanic eruptions that settled on the sea floor and formed a green layer called a tuff. Unlike some other kinds of rocks or sediment, tuffs contain crystals of zircon — a mineral that formed during eruptions and are, as the name of the rock layer containing them suggests, tough. Zircon is chemically stable as well as heat and weather resistant. It is hard as steel and persists when minerals in other kinds of rocks erode. Inside these resilient zircon crystals, individual atoms of uranium gradually decay and transform into atoms of lead. Radio isotope techniques enable researchers like Wernette to determine when the zircon crystals formed and thus put a date range to the volcanic eruption that laid down the tuff formation. 

Wernette studies stratigraphy and invertebrate paleontology with special attention to the lower Paleozoic of Gondwana and trilobites. She is interested in how the physical earth affects biodiversity, relying heavily on paleogeography and geochronology to frame this investigation. She earned her doctorate in geological sciences from the University of California Riverside, and her bachelor’s and master’s, both in geology, from the University of Oklahoma.

FURTHER READING:

Trilobites of Thailand's Cambrian–Ordovician Tarutao Group and their geological setting

Trilobites rise from the ashes to reveal ancient map

Between the weird and wonderful rangeomorphs of the Ediacaran Period and the world-famous palaeocommunities of the Burgess Shale, the 'Early Cambrian' is host to a 'waste basket' of fossils untied by their small size and shelly construction.

These small shelly fossils (SSFs) aren't just a single group of animals, but represent several different invertebrate phyla. Further compounding the difficulty of their identification, each SSF, termed a 'sclerite', is part of a larger composite skeleton known as a 'sclerotome'. Whilst some complete sclerotomes have been preserved, many SSFs still represent multiple jigsaws thrown together and the pictures lost.

Piecing the SSFs back together and building a picture of the Earliest Cambrian is Dr Marissa Betts of the University of New England, Australia. Her work on the SSFs have provided a new framework for the regional stratigraphy of Australia and in this interview, we discuss why this was necessary, how she went about it and finally, what we know about the animals themselves.

Between the weird and wonderful rangeomorphs of the Ediacaran Period and the world-famous palaeocommunities of the Burgess Shale, the 'Early Cambrian' is host to a 'waste basket' of fossils untied by their small size and shelly construction.

These small shelly fossils (SSFs) aren't just a single group of animals, but represent several different invertebrate phyla. Further compounding the difficulty of their identification, each SSF, termed a 'sclerite', is part of a larger composite skeleton known as a 'sclerotome'. Whilst some complete sclerotomes have been preserved, many SSFs still represent multiple jigsaws thrown together and the pictures lost.

Piecing the SSFs back together and building a picture of the Earliest Cambrian is Dr Marissa Betts of the University of New England, Australia. Her work on the SSFs have provided a new framework for the regional stratigraphy of Australia and in this interview, we discuss why this was necessary, how she went about it and finally, what we know about the animals themselves.

The Burgess Shale is probably the world's most famous lagerstätte (site of special preservation). Discovered in 1909 on Mt. Stephen, in the Canadian Rockies of British Colombia, Canada, this locality provided an early representation of the true biodiversity of the Cambrian Period. For decades, discoveries from this site have helped palaeontologists better understand the 'Cambrian Explosion' and the origins of modern lineages. Since that time, many more early lagerstätten have been discovered, so we asked Prof. Simon Conway Morris, from the University of Cambridge, if this well-studied locality still holds its relevance to modern palaeontology.

The Emu Bay shale is a Burgess Shale-type lagerstätte from the Early Cambrian of South Australia. We speak to Dr John Paterson, of the University of New England, all about the locality and the fossils it contains.

As Palaeocast celebrates it's 1st Birthday, we take the chance to look back over the past year and review our highlights. We also look towards the future and discuss our plans to attend some upcoming palaeontology conferences. We introduce a new member of the Palaeocast team and hear a little about the scientific work of all our members.

The Great Ordovician Biodiversification Event, or 'GOBE', describes one of the most important increases in biodiversity in the history of life on earth. During a relatively short time span of some 25 million years, an explosion of new species, genera and families appeared. This increase in diversity was accompanied by an increase in ecosystem complexity. Plankton and suspension feeding organisms rapidly diversified and became important constituents of the food web. At the same time, large predators, such as the orthoconic nautiloids, evolved to exploit them. This biodiversity 'explosion' coincided with a dynamic period in earth's history during which continents were shifting, mountains were raised and massive volcanism occurred.

Joining us to try and untangle the causes and consequences of this complex and fascinating period is Prof. David Harper of Durham University, UK.

Trilobites are one of the most instantly recognisable groups of fossils. They were present from the very start of the Paleozoic and went on the fill a great number of ecological roles before going extinct at the Permo-Triassic mass extinction event 252 million years ago. They ranged from the very small to the very large, from the most basic appearance to the most elaborately ornamented.

We were lucky enough to get the opportunity to speak to Prof. Richard Fortey of the Natural History Museum, London, all about trilobite morphology and ecology.

00:00:00 - The theme this week is 2.0. Meaning the Paleopals want y'all to create some content, and y'all did! Each story this week comes as a submission from the Paleoposse. Thanks, everyone! The Paleopals Patrick, Jacob and Ryan have formed a pack to hunt some science, as suggested by Jesse W., first by debating the potential of pack hunting dinosaurs as opposed to just good wholesome group shredding post-mortem Komodo dragon style. Fun for everyone!

00:18:26 - Unfortunately, the one thing the Paleopals can't easily crowd source are drinks, but they thought to bring there own. Jacob gets down with Irene by having a Magic Hat #9, fingers-crossed for continued availability post-storm. Ryan, with no intended commentary on the Paleoposse, sups a Certified Evil and makes Patrick commit the evil sin of envy. But Patrick is also packing tasty liquid in the form of a fresh hop ale from Sierra Nevada.

00:25:27 - Even Trailer Trash Talk got out-sourced this week! Brent suggested the trailer Margin Call on the Facebook page, and the Paleopals oblige. Will a stock market thriller get a triple A rating from the guys? Listen to find out!

00:36:32 - Elliot M. thought the guys might like to talk about a trilobite orgy. Elliot M. was right. Safe for work if you're not an arthropod or overly-sensitive. And as promised, here's a PDF (head to sciencesortof.com) with WAY more info on crustacean mating, if that's what you're into.

00:47:22 - Jacob has an e-mail from Alysia K. about the ethics of cloning Neanderthals. The guys barely scratch the surface and want to know what the crowd thinks. Good thing we gave this one a whole segment, no way it would fit as a mere PaleoPOW. Speaking of which...

01:08:15 - PaleoPOWs are lot like the rest of the show: user submitted. Short and sweet this week. Patrick has two tweets from Dustin K. and Ben V. H. Jacob has a niceFacebook comment from Georgia C. and Ryan has an e-mail from Lazlo complaining about accents (not ours) and asking for more politics.

Thanks for listening AND submitted such great stories for the week! While you scour the internet for more stuff to send us, why not drop by the Paleocave Blog? 

Music this week provided by:

Bleed It Out - Linkin Park

Hurricane - Something Corporate

Bankrupt On Selling - Modest Mouse

Hard to Find - Lit

Caveman - Jimmy Eat World