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Follow that Fish! - Transcript

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00:00            Wide & pan of Land Rover driving through quarry
                      Wide, Sandstone Quarry, researchers walk into shot
                      c.u. and tilt of quarry wall detail
                      Wide of above

Guide Voice: 400 million years ago this sandstone quarry, on the border between England and Wales, was a river. This would have been a very different landscape then – probably semi-desert around a wide, shallow water course. These researchers from the University of the West of England, in Bristol, are studying the rocks and fossils in this quarry in order to understand the landscape, plants and animals from that time.

00:22 SOT: Dr. Susan Marriott, Reader in Earth Sciences, University of the West of England, Bristol – “These rocks are river deposits from about 400 million years ago and they give us a clue as to what the environment would have been like at the time. For example, at the bottom here we see the greenish-grey rocks, those would’ve formed in quite a fast flowing river but because the rocks are covered in redder rocks that are much finer grained with different layering in them. We know that the environment changed - there wasn’t always a river flowing in this area. So for example what we can tell is that the river may have moved its position or it could even have dried up.” 

01:06            Researcher (Lance Morrissey) chipping away at rock wall
                      Over shoulder shot – chipping at wall
                      c.u. fossil of river fish showing horseshoe shaped head shield
                      c.u. fossil of river fish
                      c.u. fish model and fossil side by side
                      Wide shot, fish model
                      c.u. fish model, head shot
                      Medium wide, researchers in quarry
                      Wide, researchers in quarry
                      c.u. hand indicating fish trails on fossilised sandstone 

Guide Voice: Fossils have been found in these rocks of fish that used to swim in the river that flowed here all that time ago. These fish looked very different from freshwater fish we know today; one group, the cephalaspids, had a unique, horseshoe-shaped head shield. These fossils tell us what they looked like – but we don’t know how they moved; or we didn’t until very recently.

These fossil fish had a different arrangement of fins from modern fish and scientists have only been able to speculate as to how they might have swam – but now the researchers at the University of the West of England have made a discovery that they believe will unlock the mysteries of these early fish.

They’ve found the earliest ever fish swimming trails – marks left in the river sediment by fish as they moved over and close-to the river-bed.

01:51 SOT: Lance Morrissey, Phd Research Student, School of Geography and Environmental Management, University of the West of England – “So here we have the fossil fish trails which are - their Latin name is “Undichna” - “Und” meaning wave and then “Ichna”, meaning trace. So, in their simplest form we see them as a single sinusoidal trace that’s left here in the rock. This is the second type of fish trail which comprises these two parallel lines with these pits or resting marks at the end of them. And then that’s also seen on this slab here – we have the two parallel markings here but additionally we have a sinusoidal medial marking as well. So it’s probably the case that the fish cruised in to land, left the two parallel markings but also left a central marking, that here is straight, with its tail. It then stopped and rested on the sediment and then it decided to swim away – flicked its tail, leaving the sinusoidal marking”. 

02:56            Animation of fish swimming – overhead view (x 2)
                      Animation of fish swimming – side view (x2)                           

Guide Voice: Produced at UWE’s Bristol School of Animation, this sequence shows how cephalaspids may have swam, based on the trace fossil evidence. This is an important discovery as it offers tantalising indications of the behaviour of these early vertebrates. The fish that made these trails appear to have used their pectoral fins to rest on the sediment before “take off” – Is this the start of rudimentary limbs that would one day walk on land?

03:20 Susan Marriott – “The sediment deposits we have here are based on land and one of the important things at this time in geological history was the emergence of life from a watery environment into a land environment and what we’ve found here are some fossils and also some traces and trails of the animals that made them and so we can make inferences about the environment the animals lived in and link it the evolution of life on land.”

03:51 Lance Morrissey“Certainly back in the 19th and throughout the 20th century, the old red sandstone is very famous for preserving these fish. So the fish fossils were certainly well known but the fish trails have never been recorded from the old red sandstone before.”

04:12            Wide, Susan Marriott and Lance Morrissey study rock face
                      c.u. Susan Marriott
                      Reverse angle Susan Marriott & Lance Morrissey

Guide Voice: It’s a significant discovery – the oldest fish trails ever recorded - offering a new perspective on one aspect of life from the very dawn of existence.

04:22            End      

This material is available for use without restriction for up to 28 days following the feed date, Tuesday 27 June 2006. For use beyond this period, please contact Research-TV on +44 (0) 207 004 7130 or email enquiries@research-tv.com. 

Page contact: Shuehyen Wong Last revised: Thu 22 Jun 2006
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