The richly fossilised Transantarctic mountains have the most diverse assemblages of Devonian fossil fish on the whole planet, making the 380 million year old site an irresistible magnet for Flinders University Strategic Professor of Palaeontology John Long. FiT caught up with the intrepid adventurer back at Bedford Park, who’s just returned from two months in Antarctica as part of a major US expedition.
I’d collected fossils down in Antarctica back in the late 1980s and early 90s, and described a number of the fossil fish from there – quite a few of them were poorly known, or known from fragmentary remains. In addition to finding more complete specimens of those really interesting fossils that tell us a lot about the transition of fishes to land animals, we also found a number of new species, completely new to science. So, it’s going to be very exciting to get those specimens, when they arrive back in the States, in about May, and put some of them through a brand new CT scanner that Flinders University will have operational by then.
So, what sort of things are you looking for when you’re discovering these new species? What can they actually tell us?
Sometimes you get fossils that are just squashed flat, two dimensional, that don’t have a lot of real anatomical detail, but we found some three dimensional skulls from this site that have beautiful braincases. When you put them through a CT scanner, like we did with some of the material from the 2016 expedition, you can reconstruct the brains and the sensory systems, you can look at their special adaptations, like their hearing abilities, and their sight, and we can look at the ecological adaptations of how fish left the water to invade land and become the first land animals, and that’s the really exciting stuff about some of this material.
Are you at the point of being able to see the different branches of evolution starting to form, at those very earliest junctures?
That’s right. Some of these very peculiar limbed fish, as we call them, had their origins in Australia and Antarctica, which was part of the giant Gondwana supercontinent, and so they appear here earlier than they do in the Northern Hemisphere. So, it’s a completely new slant on the story because, up until now, we’ve heard so much about fish like Tiktaalik, from the Northern Hemisphere.
Tiktaalik was discovered by Neil Shubin and Ted Daeschler, who led this US funded trip to see if we could find something similar in the Southern Hemisphere. Although we didn’t find an exact copy of Tiktaalik, we found a number of new kinds of fish that are going to shed light on this problem of the origin of the beginning of terrestriality in vertebrates adapting to land.
What is it about Antarctica in particular that makes it both such a rich site, and so well preserved? Because we think of Antarctica as such a harsh environment, it’s almost unfeasible to think that fossils would survive, and linger, and be in such a great state; why is it the ideal spot, rather than the worst spot?
Well, in a nutshell, it’s its remoteness. When there are fossil sites, and they’re easy to get to, many people go there looking for fossils, and scour those sites, and collect all the good stuff. But these sites are so remote and difficult to get to that they’ve hardly been touched.
It’s also the fact that there’s no plants and soil growing on those mountains in Antarctica, they’re just layers of pure rock, which means you get beautiful exposure of the rocks to find the fossils. So, once you overcome the harsh environment, sometimes you can find whole slabs of rock just covered in fossil bones, and you just have to be choosy as to what you’re going to collect and pick only the good stuff. It is a really special place for a paleontologist. The fact that it was once joined to Australia means many of the species of fish I described as a PhD student from Victoria have been turning up in Antarctica, and I can recognise them.
Are there moments from the trip that are lodged firmly in your mind as ultra-special, are there those things that you’re clinging to now, just going, “Wow, that was extraordinary”?
Yeah, it’s not only the fact that we did find some good skulls of material, that’s going to be quite valuable to science in terms of this story, it’s also just the beauty of the place. Working in such a harsh environment is very draining, both physically, and mentally, and emotionally, being isolated from so long, from family. We were actually down there for two months, and I haven’t done a trip that big for 30 years, so it’s a long time to be living in a little tent, and just putting up with the storms and the harsh weather.
There were also a lot of demons I had to visit, because in my earlier trips I had very close calls with crevasses and avalanches, and I was very wary about going back to sites where that happened, and ultimately I chose not to. So, yeah, there’s a lot of stories there – not just about the fossils, but also about being human in such a harsh environment – that you have to deal with when you’re working down there.