Saturday, 8 December 2012

Team Member Profile – Jenny Clack

This post is the first of a series of profiles about the scientists working on the TW:eed project, so you can find out who they are and what they do. Our opening profile is of Professor Jenny Clack FRS, the lead Principal Investigator for this exciting multidisciplinary project.

Over the last 20 years Jenny has made major contributions to early tetrapod palaeontology, especially in discovering, describing and analysing new and recently prepared material from the Late Devonian and Early Carboniferous periods. Her work has changed perceptions about the evolution of tetrapod organ systems (limbs, breathing and hearing) and these concepts are now included in standard biology text books.

Jenny is the driving force behind the project. Determined to understand more about terrestrial ecosystems and the acquisition of terrestrial capability by tetrapods in 25 million years that followed the end Devonian mass extinction, she assembled the team of scientists now working on TW:eed. In addition to her research on these Early Carboniferous vertebrate fossils, Jenny is also in charge of co-ordinating this four-year project.

Where do you work?
I am based at the University of Cambridge and am Professor and Curator of Vertebrate Palaeontology at the University Museum of Zoology, an integral part of the Department of Zoology. I have several different strands to my work: curation, teaching, research and some administration.

What inspired you to pursue a career in vertebrate palaeontology?
I’ve been interested in fossils and all aspects of natural history and sciences since childhood, although fossils and palaeontology were a favourite. Thus I followed a career in biology through school and university. After my first degree, although I would have liked to work on a PhD in vertebrate palaeontology, opportunities were not available. Instead, I entered the museum world, via holiday work, a Museum Studies degree and then a spell of 7 years in Birmingham Museums and Art Gallery. At that time, they had a Natural History department and a Museum Education department, and I worked spells in both. (Both are now gone.) During the latter spell, I was given the chance to renew my attempt to enter the field of palaeontology by returning to my first university for a PhD.

What would be an ideal working day?
Discovering new fossils, thinking about and examining fossil material that I or others have prepared, microscope work and illustrating specimens. Then writing them up for publication, which I don’t usually find a chore, but actually enjoy doing.

What do you think are the key character traits needed to be a successful palaeontologist?
It depends on what kind of palaeontologist you are. Many aspects of the field are now computer-based, but for my kind, who are interested in the actual materials and the animals they represent, an ability to think in three dimensions, to visualise anatomy, to interpret mashed-up fossils. You sometimes have to turn your first thoughts on their head (not literally) and not be constrained by received ideas.

Do you have favourite fossil from all those that you have studied?
Probably the one I did my PhD on, if I have to choose. It’s a Coal Measures tetrapod called Pholiderpeton and it belongs to a group called anthracosaurs. It’s quite a big beast, one you might describe as road-kill except that the bones are well preserved if disarticulated. It provided new insight and thoughts about several previously unknown aspects of anthracosaur anatomy. In effect, it launched my career. Maybe that’s why the Romer’s Gap project is so appealing – it’s back to the Carboniferous for me.

What was your inspiration for setting up the TW:eed project?
The knowledge that my colleagues Tim Smithson and the late Stan Wood had found numerous fossils from a previously almost blank period for fossils lasting about 20 million years and covering the time period during which terrestrial tetrapods and modern-aspect ecosystems were becoming established. If I had been asked what I most wished for in the closing years of my career that would have been my answer. The project then grew and grew, and it was quite difficult not to take on too much.

What are the major scientific challenges in vertebrate palaeontology?
Although many of my junior colleagues have recently been appointed to academic positions, funding long-term will be a problem. However, more fossil material is being discovered all over the world and brilliant new techniques are helping to formulate new ideas and questions. Linking these to evolutionary developmental genetics will play a larger part in our activities, and looking at animals’ morphology, growth trajectories, biomechanical potential and palaeoecology in more sophisticated ways will be other growth areas.

When you aren’t thinking about vertebrate palaeontology, what do you like to do?
Singing. My husband and I sing in two choirs which together take up a lot of our time outside work. We also spend a lot of time gardening.

If you want to find out more about Jenny’s research and ideas:

Clack, J. A. 2012 Gaining Ground: the origin and evolution of tetrapods, Second Edition. Indiana University Press, Bloomington, Indiana, USA. 544pp ISBN 978-0-253-35675-8

And visit Jenny’s webpage:

Until next time

Crushing rock – part 2

In this short post I will continue to explain the process of rock crushing. The final stage is to take the millimetre size rock pieces and to crush them up into micron size pieces, a process called milling. We use a machine called a Planetary Mill, which you can see in the photo below. There are four receptacles with balls inside that spin round and crush the rock into small grains. The result is a fine rock powder, which feels quite like flour. We use this rock powder for various geochemical analyses such as determining the carbon isotopic composition of the rock.

For my rock samples this is a fairly quick process, as sedimentary rocks are not very hard compared to igneous and metamorphic rocks. However, a lot of time has to be spent on cleaning the receptacles and machine between each batch, to avoid contamination. 

Top: The Planetary Mill. Bottom left: one receptacle containing rock pieces and balls to crush the rock. Bottom right: the resulting powder produced by milling.

Wow! Of the week
When I found this rock while sawing last week, it was a total wow! moment. As before, with other wow! specimens, on the outside the rock looked very non-descript, just a sandy lump. But once I sawed into the rock I saw all these holes throughout the rock that I haven’t seen before. I tested to rock with some dilute acid and discovered that calcite exists in the holes, while the rest of the rock is made from sand. I think that these holes were formed by gypsum crystals that have now dissolved, as some of the holes are long and thin like the crystal habit of gypsum.

This is the first direct evidence I have found of gypsum from the site I am working on. Its very exciting as it means that this rock formed from the evaporation of water, maybe in a lagoon that dried up. And it might indicate that seawater inundated the area prior to its drying out. In the bigger picture, its one more piece in the puzzle of understanding the environment the tetrapods lived in, fantastic!

Until next time