Palaeocast

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.

Fossilisation of organic material was long thought to result in the complete loss of original content. However in the last 20 years, several high-profile publications reported the discovery of proteins, blood vessels, blood cells and even DNA. But for as long as these arguments have existed, so too has a counterargument as to the validity of the discoveries.

In this episode, we're joined by Dr Evan Saitta of the Field Museum of Natural History, Chicago, lead author of a recent paper seeking to discover and evaluate the preservation of putative original organic materials within dinosaur bones.

One of palaeontology's great themes of questioning is the rise of novelty: how new structures and functions arise in specific lineages. In this episode we speak with Neil Shubin, Professor of Organismal Biology at the University of Chicago, who has been studying novelty in the context of the vertebrate transition from water to land.

Neil studies the fossil record of early tetrapods, the first vertebrates with limbs, to understand what changes underpinned this great transition. The other half his lab uses molecular techniques on living organisms to see how changes to the development of appendages (and their underlying genetic architecture) effected the shift from a fin to a limb.

In this interview, we hear about his fieldwork in the Arctic and Antarctic, how palaeontologists decide where to look for key fossils, why development matters, and about his deep involvement in science communication.

Undoubtedly, Megalodon is the world's most famous extinct shark is and in this episode, we hear everything we know about this taxon, its ecology and how it got to be so big. Its ultimate extinction is also considered, not in isolation, but placed in the wider context of the entire marine ecosystem.

Joining us is Dr Catalina Pimiento of Swansea University.

From 1:1 scale whales to microfossils scaled up to the size of a house, there are few model-building projects that 10 Tons are afraid to take on. At the helm of this business is Esben Horn and in this episode, he joins us to discuss the process of model building, from concept to museum display.

We also talk about some of the exhibitions 10 Tons have led themselves, including the successful 'Rock Fossils on Tour' which showcases some of the different fossils named in honour of rock/metal musicians.

Opsins are the photosensitive proteins in the eye, responsible for converting a photons of light into an electro-chemical signals. Different opsins react to different wavelengths of light, each corresponding to a different band of colour. In humans, the 'visible spectrum' of light (a very anthropocentric term) is covered by three opsins, receptive to red, green and blue wavelengths. Other animals have opsins that are capable of subdividing the 'visible spectrum' and responding to a large number of very specific wavelengths of interest. All in all, the ability to detect light and recognise colour is not the same throughout the animal kingdom.

In this episode, we are joined by Dr James Fleming of Keio University, Japan to discuss the evolution of opsins in the ecdysozoa (the group containing arthropods and a fair few worms). We talk about the fundamentals of light detection and how, using phylogenetics, we are able to tell which colours certain extinct animals were capable of detecting.

Decapods are a group of crustaceans that include such well-known families as crabs, lobsters and shrimp. Whilst crustaceans are known from as early as the Cambrian, we don't see the first decapods until Devonian. Over the course of their evolutionary history, decapods have remained relatively conservative in their morphology with the exception of some interesting forms in the Mesozoic.

In this episode, Dr Carrie Schweitzer, Kent State University, gives us a run-down of the taxonomy and evolutionary history of the decapods and we explore the Middle Triassic Luoping Biota.

The interaction between plants and atmosphere forms the basis of the carbon cycle and is amongst the most important processes for maintaining life on the planet today. Photosynthesis removes carbon dioxide from the atmosphere and in return forms the base of the food chain and produces the oxygen we, as animals, need to breathe. Equally, the composition of the atmosphere influences the climate and thus the availability of resources, governing where plants are able to survive.

The relationship between the two can be committed to the fossil record by such physical proxies as the number of stomata in leaves and by the palaeolattitude of different species. Other chemical proxies, such as isotopic ratios, can also help elucidate what the atmosphere was like at the time a plant was preserved. Similarly, atmospheric proxies can also be used to make inferences about past plant life in the absence of fossil remains.

Joining us to discuss the link between plants and atmosphere is Prof. Jennifer McElwain of Trinity College Dublin, Ireland.

The Carboniferous was a time of huge swampy forests, big trees, and lots of life both on land and in the ocean. One world-renowned fossil site from approximately 300 million years ago is the Joggins Fossil Cliffs, located on the Bay of Fundy in Nova Scotia Canada. Joggins is one of Canada's five palaeontology-based UNESCO World Heritage Sites, and is one of the best places in this world to find fossils from this time period.

Why are the Joggins Fossil Cliffs so important? What makes this locality unique?

In this episode, Liz speaks with Dr. Melissa Grey, the curator at the Joggins Fossil Centre to learn more about why this region is so important. We discuss the variety of fossils, from plants to invertebrates to vertebrates, and how the interesting preservation has resulted in virtually an entire ecosystem being preserved.