Palaeocast

Crocodiles are often referred to as “living fossils”, but if we compare modern and ancient species, does that label hold up? What different kind of morphologies (shapes) did past crocs have and how did they live? How quickly did this past diversity arise and why are we left with so few species today? What’s to stop them from diversifying again?

In this episode, we speak to Dr Tom Stubbs, University of Bristol, about his recent work analysing changes in crocodylomorph disparity through time. We look at some of the weird and wonderful crocs of the past and work through his methods for calculating their rates of evolutionary innovation. Part 2 of 2

Direct download: Ep125.mp3
Category:general -- posted at: 1:05pm UTC

Crocodiles are often referred to as “living fossils”, but if we compare modern and ancient species, does that label hold up? What different kind of morphologies (shapes) did past crocs have and how did they live? How quickly did this past diversity arise and why are we left with so few species today? What’s to stop them from diversifying again?

In this episode, we speak to Dr Tom Stubbs, University of Bristol, about his recent work analysing changes in crocodylomorph disparity through time. We look at some of the weird and wonderful crocs of the past and work through his methods for calculating their rates of evolutionary innovation.

Part 1 of 2

Direct download: Ep124.mp3
Category:general -- posted at: 5:06pm UTC

Terrestrial life as we know it couldn’t exist without soil. Soil, as we know it today, is a layer of minerals, organic matter, liquids, gasses and organisms that not only provides a medium for plant growth, but also modifies the atmosphere, provides a habitat for animals and retains and purifies water.

This kind of soil hasn’t always existed, so in order to understand early conditions on land, we first need to understand what can be constituted as a soil and when these first appeared. Is there soil on the Moon? Can soil fossilise?

Since most terrestrial ecosystems are rooted in soil, if we want to understand how life established itself on land, we first need to know how soils form, how they have changed over geological time and which kinds of plants and fungi can live without it.

Joining us in this episode is Dr Ria Mitchell, Experimental Officer in X-ray Computed Tomography at the University of Sheffield, UK.

Direct download: Ep123.mp3
Category:general -- posted at: 5:12pm UTC

Part two of our interview with Dr Larisa DeSantis of Vanderbilt University on the 'dietary ecology' of Smilodon.

Smilodon is probably one of the most iconic mammalian apex predators with its extended upper canines and robustly-built forearms. In fact, when we compare Smilodon to modern cats (felids), we don't see these same characteristics. So what were they used for? Was Smilodon specialised for any particular behaviour?

Owing to the unique preservation of the tar seeps at Rancho La Brea, Los Angeles, USA, we can find an overabundance of predators, including Smilodon fatalis, Canis dirus, Panthera atrox and Puma concolor. This allows researchers to reconstruct the predatory landscape of the area in the Pleistocene. Who was eating what? Was there any competition between predators?

Direct download: Ep122.mp3
Category:general -- posted at: 2:48pm UTC

Smilodon is probably one of the most iconic mammalian apex predators with its extended upper canines and robustly-built forearms. In fact, when we compare Smilodon to modern cats (felids), we don’t see these same characteristics. So what were they used for? Was Smilodon specialised for any particular behaviour?

Owing to the unique preservation of the tar seeps at Rancho La Brea, Los Angeles, USA, we can find an overabundance of predators, including Smilodon fatalis, Canis dirus, Panthera atrox and Puma concolor. This allows researchers to reconstruct the predatory landscape of the area in the Pleistocene. Who was eating what? Was there any competition between predators?

All of these questions feed in to the ‘dietary ecology’ of Smilodon and here to discuss that, and more, is Dr Larisa DeSantis of Vanderbilt University.

Direct download: Ep121.mp3
Category:general -- posted at: 8:17pm UTC

It wouldn’t be outlandish to state that many a fossil collection has started with the acquisition of an ammonite. Their planispiral shells (termed a conch) are instantly recognisable and since that conch was originally composed of the relatively hard mineral aragonite, they better lend themselves to the fossilisation process.

But how much do we actually know about the animal that produces the conch? We might be able to make superficial inferences based on comparisons with the modern Nautilus, but ammonites are actually closer related to squid and octopuses.

So could you recognise an ammonite without its shell?

Prof. Christian Klug of the University of Zurich has recently described just that: a naked ammonite. In this episode, we learn about ammonite soft body anatomy and sink our teeth into the mystery of how this ammonite lost its shell.

Direct download: Ep120.mp3
Category:general -- posted at: 5:52pm UTC

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