On today's episode we're revisiting Mistaken Point, Newfoundland, Canada. At this lagerstätte it is possible to find large bedding planes full of Precambrian organisms called rangeomorphs. These are an enigmatic group, which still can't be placed on the 'tree of life'.

We are joined by Dr Emily Mitchell of the University of Cambridge, who's recent paper in Nature was able to show that you don't need to be able to fully understand the anatomy of an organism to discern some of its most intricate details.

Synapsids are one of the major groups of terrestrial vertebrates. They first appear in the Carboniferous period and since that time have gone through many radiation and extinction events. But what did these first stem-mammals look like, how did they live and how do they differ from modern mammals? These may sound like simple questions, but there is an underrepresentation of terrestial deposits from the Permian. How then can we understand larger-scale evolutionary patterns when so much data is missing?

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.

It's been quite a week for lobopodians!

First off, we've had the redescription of Hallucigenia by Dr Martin Smith. This enigmatic fossil from the Burgess Shale typifies the difficulty palaeontologists have had in interpreting some of the earliest animals in the fossil record. It has famously been reconstructed upside-down and is now shown to also have been back-to-front too! Dr Smith joins us to tell us about the observations, including some new anatomical characters, that put an end to the uncertainty of the orientation of this animal.

Secondly, there's a older and more heavily-armoured lobopodian from the early Cambrian Xiaoshiba biota of China that we've got the exclusive on. Collinsium ciliosum is described today and we're also joined by one of the lead authors Dr Javier Ortega-­Hernández.

The world is currently undergoing a massive biodiversity crisis, and many people have said that we are in the next major mass extinction event, with species going extinct each day. Unfortunately, we don't currently understand what aspects control biodiversity, and how the past can help us understand the present and the future.

Associate Professor Lindsey Leighton of the University of Alberta discusses his work combining research of modern invertebrate marine fauna related to biodiversity and ecosystems with studies of the fossil record in order to further understand this problem.

The Cretaceous-Paleogene (K-Pg) mass extinction was the latest of the 'big five' events. Approximately 75% of species went extinct, with the most notable victims being non-avian dinosaurs. But what happened afterwards? By which methods were some of the survivors able to spread to fill vacant niches?

The University of Bath's Dr Nick Longrich joins us to hypothesise about the dispersal mechanism of a very unusual group of ground-dwelling predatory reptiles called amphisbaenians (worm lizards).

We've covered ichnology before, in Episode 14, but it's time to revisit trackways with a high-tech approach. We talk to ichnologist and computer expert Dr Peter Falkingham, from Liverpool John Moores University, who's been looking at footprints using state-of-the-art techniques.

After the success of last year’s palaeoart competition we’re stepping up a gear and launching an even bigger and better contest. This time we've got three times as many prizes to give away courtesy of Cider Mill Press, Palaeoplushies and Paleocreations.

We're running the competition on Facebook and Twitter between the 1st May and 1st June using #palaeocastart.

DNA (deoxyribonucleic acid) is a molecule that encodes the genetic information within every species of life on earth. The information contained within the sequence of base pairs determines how any given organism develops and biologically functions.

DNA is not just limited to the biological world, but is also now being utilised in palaeontology. But why is DNA not normally preserved? What's the oldest DNA we can recover? And what can we learn about fossil animals from their DNA? We spoke to ancient DNA expert Dr Ross Barnett in order to get answers.

Palaeontology is more than just going out into the field, digging up bones, and putting them back together. A good understanding of biology, geology, and even engineering can help to figure out how extinct animals lived and especially how they moved around.

To further comprehend how we can use knowledge of engineering in palaeontology, especially with respect to understanding extinct animal flight, we spoke to Colin Palmer from the University of Bristol, and the University of Southampton. His background in engineering provides a unique set of skills and angle to studying pterosaur flight.