Show Notes
Determining the origin of teeth in vertebrates is an incredibly significant but notoriously difficult problem within palaeontology. Teeth didn't evolve in the mouths of our ancestors, but are first seen as part of the external skeletons of jawless fish as structures called 'odontodes'. These would later migrate into the mouth with the evolution of jaws, becoming the teeth we have today, but odontodes still remain present in the skin of modern cartilaginous fish, giving them their rough texture. The oldest known odontodes are from the late Cambrian Period and represent the very first evidence for vertebrates in the fossil record. Unfortunately, they are only ever found as part of fragmentary pieces of exoskeleton, however, given that their specific construction is only known in vertebrates, there is little else they could possibly be… Joining us for this episode is Dr Yara Haridy, University of Chicago, who set out to use modern new scanning techniques to better understand the nature of these first teeth and what they tell us about the evolution of vertebrates. What she discovered was unexpected, but also led to better understanding of the purpose of odontodes in the dermal exoskeletons of our ancestors.
More from Palaeocast
The Cambrian Explosion is one of the most significant events in evolutionary history. Classically, it describes the sudden appearance of complex fossils (including all major animal groups) at the beginning of the Cambrian Period. Before then it was thought that only relatively simple single-celled or multicellular life existed. We now understand this event to be a lot more nuanced, recognising many of the geological biases at play and having discovered complex fossils in the earlier Ediacaran Period. Many researchers therefore consider the term 'Cambrian Radiation' to be a better representation of the event. Whether an explosion or a radiation, determining the events of the Ediacaran and Early Cambrian and their causes is a constant area of palaeontological research. Numerous drivers behind this event have been hypothesised ranging from oxygen availability and nutrient cycling to an arms race between predators and prey. It is likely that no single factor will be identified as an underlying cause, but the relative extent to which each contributed to the event will be debated for many years to come. In this interview, we are joined by Dr Julien Kimmig, Staatliches Museum für Naturkunde Karlsruhe, Germany, who recently authored a study on the coprolites of the Early Cambrian, the evolution of guts, and the influence the 'Cambrain Fecal Revolution' may have had on the wider Cambrian Radiation.
The Carboniferous period is host to some of the largest arthropods to have ever lived. Giant taxa such as the griffenfly Meganuera and the millipede Arthropleura are almost talismanic and are often depicted in reconstructions of the period. Since many other groups also have giant representatives in the Carboniferous, what is it about this time that allows for arthropods to grow to such large sizes?
The Carboniferous period is host to some of the largest arthropods to have ever lived. Giant taxa such as the griffenfly Meganuera and the millipede Arthropleura are almost talismanic and are often depicted in reconstructions of the period. Since many other groups also have giant representatives in the Carboniferous, what is it about this time that allows for arthropods to grow to such large sizes?
Prof. Paul Barrett of the Natural History Museum, London, recently authored A History of Dinosaurs in 50 Fossils. We took this as an opportunity to get an overview of what we really know about dinosaurs and how it's even possible to tell their story with just 50 specimens.
Petrified Forest National Park in northeastern Arizona, USA is a hub for Triassic palaeontology and has exposures representing 20 million years of the Late Triassic Chinle Formation. Visitors marvel at the colourful fossilised trees from which the park takes its name, but a whole host of animals called these swampy forests home 225 million years ago. In this episode, we talk to Dr. Adam Marsh, lead palaeontologist at the National Park. We explore the history, geology, and palaeontology of Petrified Forest, along with exciting research centred around specimens from the park. Research is ongoing, with many groups of palaeontologists working on Petrified Forest specimens, and we hear about directions it might go in the future.