Exceptionally Preserved Fossils: Windows on the Evolution of Life

right good evening everybody ladies and gentlemen almost full up which is very good welcome to the Geological Society of London and to this the third shell lecture for 2013 entitled exceptionally preserved fossils windows on the evolution of life my name is David Shelton I am the president of the Society and it's my pleasure to thank shell for making this series of very successful public lectures possible and our understanding of the history and evolution of life on Earth relies heavily on the fossil record and especially in rare cases of so-called exceptional preservation where the soft parts of animals and indeed in entire soft bodied organisms are preserved such exceptionally preserved fossils provide unique insights into animal paleo biology and the true nature of biodiversity and they have proved crucial in filling the gaps that we devil the fossil record they literally flesh out our knowledge of history of life and help to resolve controversies about the biological relationships of animals still alive today our speaker today is David Savita emeritus professor of paleontology at the University of Leicester and a former chairman of the micro paleontology paleontological society a society which is rather larger than its name suggests ladies and gentlemen please welcome professor well thank you very much for that introduction mr. president and good evening ladies and gentlemen it's a pleasure to be here to give this lecture and I thank the Society for inviting me and also the sponsors there's a fossil sand this is my business I'm a paleontologist and I have the supreme privilege to look at beautiful things every day that's not just the people who are walking around the campus it's these things I've always considered to be a great privilege to be a paleontologist and fortunate to make a career out of it so fossils vary in their shapes and sizes from minut pinhead sized fossils like this to dinner plate fish to fellows like this which every schoolboy knows this is a Tyrannosaurus Rex which I fortunately had the great privilege of putting together for an exhibition which still stands in my university geology department did this about three or four years ago and not many paleontologists can say that they've put a t-rex together but I have and that's almost the crowning glory on on my career but although the fossils are beautiful and aesthetically they're so beautiful to look at we mustn't forget that fossils are to us very important scientific tools so I just like to take a few moments if I may to tell you why fossils are important firstly they help us reconstruct lost worlds the rocks that you see here are of Silurian age four hundred and twenty-five million years it's a quarry in the Welsh borderland in the county of Sirach here and if you look very closely actually here and here the rocks are very replete with coals here we see a beautiful little coral colony and there are others through here now if we go to modern environments this is a photograph of the Barrier Reef we can also see coals and using the simple principle of uniform arianism of the present is the key to the past we can take information about the conditions under which these modern corals live and transfer it back to the fossil record so modern corals normally live only in warm shallow sunlit environments and in salty water normal the ring salinities so we can take that information back to these rocks in shropshire and interpret lost worlds they could the condition under which these ancient corals grew I might add that the time we're talking about England was in the subtropics a little bit different from what we have today fossils could also help in reconstructing paleo geography now this is a map of the world and about 525 2025 million years ago and it's very different of course Britain you might be interested is here about 60 degrees latitude SAS and it feels like it today the continents are not where you might expect them very Scandinavia here is ancient North America and that picture of ancient paleo geography was put together using a lot of geological information from structural geology and plate tectonics to geophysics but also the point I want to make is that US paleontologists have a crucial part to play in assembling ancient continents and testing ancient paleo geography from an entirely different and independence viewpoint I destroy your attention to this South China with this Rome here because this marks the occurrence of a particular exceptionally preserved fossil biota called the Qin Jiang biota which I'll come to in a moment those also are very important in dating and correlating rocks this is a stratigraphic sequence from the age of the earth about 4.6 billion years ago to the present and fossils occur in layers and they can be used to characterise layers as William Smith portrait adorns the reception area here at the Geological Society as he instructed us in the early 19th century fossil layers are characterized but layers of rock are characterized by different types of fossils and we can use this characterization to date layers and hence to correlate them across the globe the other facet which is important importantly illustrated in this slide is that of course life changes through time evolution takes place from very primitive forms of life here to even 3 billion years plus some people would argue two forms of life with nucleus in the cell two forms of life that we recognize today there's a gradual change now of course it was Darwin who gave us the mechanism for evolution by natural selection but one might argue that fossils provide the direct evidence we can go out and test there is using fossil evidence in the rock record the fossil record is pretty damn good actually possibly better than we might expect perhaps various estimates but perhaps 15 percent of life-forms are eventually fossilized many types of life are lost to the fossil record they are not preserved so the fossil record is biased so if we can find fossil by Otis which lessens that bias nature these are very important and this is what is the subject of my talk this evening this is how paleontologists normally operate here we have a large Jurassic vertebrate being excavated and we normally find bones in this case vertebrates or shells of animals the chance soft part preservation or something like the jellyfish are pretty slim here we come into the bias nature of the fossil record and yet the vast majority of animals living in marine environments today are either entirely soft bodied or large and soft bodied so we stand the chance of losing in the fossil record a large part of life as its evolved through time occasionally we find exceptionally preserved fossils like this mammoth from the Siberian tundra and when we do that when we've got the soft parts the soft tissues and the hard parts this is really the jewel in the paleontological crown it gives us a window an insight into the paleo biology of animals the paleo ecology of the biota that you're looking at the evolution and affinity of these animals it gives us that insight which would be impossible to get if the bones are load remained so this is the nature of an exceptionally preserved biota they have a special term largish Stenton essentially comes from German mine mining tradition which means a kind of mother lode of fossils and longest Etna dotted through the geological record there are about sort of 15 or so blockbusters very important but scattered all the way through the geological record you might find examples of a fossil here and there showing exceptional preservation and what I want to do now is to show you some exceptionally preserved by Otis through time and concentrate on two in particular which I and my colleagues have been working on I suppose if I any schoolboy or maybe anybody in this audience name me one longer Stetten then this would come to mind this is the iconic burgess shale Cambrian in age middle Cambrian man it was here in the first decade of the last century on these slopes that Charles Walcott discovered the famous burgess shale biota of which this is one fossil you can see that it has not only got the hard shell preserved but also elements of the soft paths these are antennae sticking from the front of this Arthur pot and the Burgess Shale for a century is acted like a beacon of exceptionally preserved fossils much studied much lauded and hugely important scientifically but in the last twenty years there has been another Cambrian biota coming on stream exceptionally preserved which certainly rivals the Burgess Shale and that biota is called the Qin yang biota and it occurs here many of you I'm sure have been to China this is Emperor Wan Li it was the longest serving Ming Emperor ruled for 47 years then of course Emperor's had palaces this is the forbidden palace I love this building it's it's named the hall of perfect harmony beautiful name where the Emperor used to receive guests and take refreshments and of course Emperor's got buried like this one Terracotta Army and bridgid who first unified China in many ways this the Terracotta Army was discovered in 1974 just ten years later in 1984 a Chinese scientist called Hassan Wang good colleague and friend discovered the Chang Jiang biota in Yunnan Province in southern China and it's a scientific discovery of great importance at least equal to that of the Burgess Shale and the discovery was made here in southern China there's beijing nanjing this is the area which is magnified here Chen yang where the fauna was discovered it's just south of the Chinese city of Kunming the capital of Yunnan Province which has about 40,000 people in it the province that is I always think again I'm privileged to work in China and particularly in Yunnan which for me is the most exciting part of China because not only is it at a topographic crossroads at the eastern end of the Tibetan Plateau it's also a cultural crossroads China has about 40 ethnic minority races and the vast majority like this by minority lady our incoming province and so it's exciting place to to actually work for many different reasons and I say in 1984 hot young Wang discovered the Chang Jiang biota quite by accident in a way and the rest is history interesting the French were into coming and Yunnan Province mapping it geologically in the first decade of the last century so exactly when Wolcott was discovering the Burgess Shale in North America the French were mapping yunnan province and here is a geological map it's in the archives as a society this is where I obtained it from this is the geological map of the Cambrian I ran for Chen lake near Chang Jiang the town of chin Jiang is here and they collected fossils and they publish them in monographs published in the first two decades of the last century but no soft-bodied fossils these soft body fossils lay waiting for another 80 or so years just think what might have happened had the French discovered soft-bodied fossils at the same time as Walcott had discovered the Burgess Shale interesting isn't it the French also left over a deficit on the landscape I was amazed after fieldwork to find a Catholic Church in southern China and I was amazed to go into the church and find that the stained-glass windows didn't have religious iconography they are grapes and these are vineyards so here you have Chinese wine industry flourishing and as we all know they're buying up the world's best wine other than ninth producer now and probably that about the 9th or 10th consumer of wine so yes this is funded now by Hong Kong money but the French left a lot but they didn't discover the Qin Jiang biota this is where we do our fieldwork here in the hills surrounding Foshan Lake very beautiful area and this is how we do it we employ local labor and forgive me but it's very sexist the guys actually do the back-breaking work of getting large chunks of rock but stone and silt stone from the outcrop and the ladies though otherwise would be tending the paddy fields the ladies aren't just brilliant at finding beautiful fossils they have an eye which they develop very quickly and they can find a fossil even where a professional paleontologist wouldn't find a fossil so these are valuable members of the team breaking open rocks to discover fossils and what fossils they discover this is a worm 525 million years old and as fresh as a daisy it's almost as if it died yesterday it has all the features here of the anterior end preserved this dark trace here is we presume to be the gut so you're looking at the last the preservation of the last male this that this worm had all those millions of years ago worms a common component of the chenggang biota and we find trace fossils the remains of traces through the sediment we're presumably worm-like animals borrowed on their way to try and find food so we have animals living in the sediment at that time and we have animals living on the sediment at that time here we've got purported sea anenome reconstructed here this is the actual specimen and here undoubtedly our sponges our sponges are just bags of jelly all together by mineral spicules silica calcite inside in other cases but here and nearly as paleontologists we find them just as spicules in residues when we break down rock we very rarely find complete ones these are complete sponges here is the reconstruction on the sea bottom and it would sit there filtering water through and obtaining food in that way and these are of different sizes and so even in the lower Cambrian we had what ecologist would term tearing of animals anymore sitting on the bottom and different sizes grabbing different parts of the water column for food that would be at a lower tier than that particular sponge and every time I look at this animal it's difficult to believe what you're looking at you're almost elucidating it's a worm like animal but a worm with legs 16 pairs of legs and use this to crawl across the substrate it belongs to a group which paleontologists called lava pods and some people would have that they are related to a modern group of animals called The Velvet worms the Anika forms interestingly modern velvet worms are terrestrial abased they live on land but this is of course in a fully marine environment so a different ecological aspect but a beautiful specimen and there's not just this genus but other general of loba ponds they're about half a dozen general of lava pods now found in the change yang biota so this thing will be cooling on the bottom and so would this thing here this is a genius named after that late foots only so this is focus on Helia and it's a beautiful arthropod you can see the segmentation here there's the head shield notice if you will hear those there are eyes now this is the first time in the geological record that you have a lot of animals with eyes in the lower Cambrian just think what that means in ecological terms for the first time animals can see and they can be seen for the first time animals can hunt and they can be hunted it's not too difficult to see a kind of ecological arms race developing because of the advent of vision this pair of diagrams comes from a paper by Moshe are actually one of my ex research students with colleagues and Lester who is now at the Natural History Museum working with graduate education she published a specimen of Fuchs own urea which showed the eyes here and this incredibly is the brain so we have the eye capsules here with nerve centers the retina and various parts of the brain which operate appendages it's a incredible feat of preservation to have such detail preserved this is a reconstruction of for failure as it might have appeared walking on this on the sea bottom and we have any moles that are swimming off the bottom in the water column perhaps near the bottom this is a beautifully preserved arthropod called LeAnn Kolya the head area is fear tail is here we're looking in a lateral view and this is an appendage sticking out at the front but I'll draw your attention to these appendages that one that one that one these are large paddle shaped appendages easily to see how these might be adapted for locomotion for swimming and this thing probably we think swam on or near the bottom and it would be joined in that particular realm by China bites and trilobite like relatives this is an arthropod called the ride and the rides are believed to be trilobite by some workers and not trying to bites by others but the rides are interesting because they are fully soft bodied and my trailer boats they don't have a hard carapace and trilobite and the rides would have joined this fella swimming in a net o benthic habitats the rides some of them in fact have a beautiful appendages there is the by ramus appendage the outer branch with filaments maybe they use this for gills and the inner branch maybe for walking with spines on the end here which may have been used for scavenging food there is a whole plethora of bivalve doll for pods off the pods which have two shells of that soft pots in between this is one of them called ice Oxus again appendages for locomotion beautifully developed eyes which you can see here and this one this particular genesis noxious we find it in many localities worldwide we have it in North America we have it in green and we have it in China and so on this fellow could get around it was a real swimmer and here we have what might be viewed as the top of the food chain in the changing biota this is an animal called while it's an anomaly carried anomaly carrots are known they're one of the iconic fossils in the burgess shale and these things were serious animals they are estimated to be over a meter in size top of the food chain in the lower Cambrian and they're armed with wrapped all or appendages at the frontier and if we were to turn this animal over it has a ring of plates to deal with the food surrounding the math these are just a pair of these rattle or pen dishes preserved in Chen Jiang so this was a serious animal if he came towards you in the lower Cambrian sea and was a kind of king in the ecosystem there and for those of you who like fishing we have what is purported to be the world's earliest vertebrate here earliest fish the Changjo biota was originally discovered in Chen Jiang and surrounding areas but it's been there found wider afield and the sedimentary basin which contains a soft bodied forest stretches over several hundred square kilometers and to the west of Chang Jiang in heiko I'm here trying to find these fellows which other world's earliest purported vertebrates we've got purported sensory organs here a dorsal thin muscle blocks going down the back and gills here reconstructed if you'd have told me when I started my career that we would have vertebrates in the Cambrian and so beautifully preserved I would say nonsense but we have them and this particular fossil really has no rights whatsoever to be preserved to get into the fossil record it's a seeker spray a tenner for or cons yelling and here it is in all its glory and it locomote through the water column by having rows of cilia aligned along its body area and it has tentacles here which is used in the modern sea goes Bruce to to get food this is just a bag of jelly and shouldn't really be preserved in rocks 525 million years old but it is so we put this kind of information together and see that animals in the lower Cambrian were doing all the kinds of things that we expect animals to do at the present time we have animals floating in the water column and swimming in the water column this is that large predator by the way anomaly carried dealing with one of its prey there's the ring of of plates around its mouth grasping the prey looks like an arthropod they're grasping of prey with these rock taller appendages we've got animals on the bottom rooted on the bottom we've got animals badger crawling across the bottom we've got animals burrowing into the sediment so this image tells us two things really first thing the chang-chang biota is the most important biota in the world for reconstructing lower Cambrian ecosystems there are other deposits as I've mentioned later on in the lecture but this is the most complete and diverse there are more than 200 species and 16 file and described now from the chain gang biota and you're looking at snap picture of the world's earliest complex marine ecosystem and this thing would probably have been repeated not just in China but elsewhere this is a very interesting fossil from Chen Jiang and when we saw it down the microscope we couldn't quite believe what we were looking at it's a chain a daisy chain of fossils and there are more than 20 individuals here and when you look at them in detail you'll find that one individual it has a shell and a tail with segments it's got his tail popped into the front end of the animal behind it and there's a polarity to these animals they're all facing in the same way they're not random and for our money we describe this in science about three years ago for our money this is an arthropod it's got all the characteristics one might like to find in an alpha pod except for legs we don't have the legs which is important unfortunately appendages but what was he doing why were these arthropods 525 million years ago in a daisy chain we tried to look to modern analogs to see if we could find some hints were they doing it for defense for protection were they doing it for migration for example lobsters migrate in a train if you go to the Caribbean you'll find lost as migrating in it in a train but there's a very big difference between a train and a chain this is an integrated linear chain with polarity so what were they doing defense migration sex were they coupling for reproduction answers on a postcard please because we couldn't answer that question but what it gives us here is a snapshot of the earliest good example of collective behavior in animals if I go to China and I see a group of Chinese schoolchildren walking outside school they walk exactly like that and in handling a chain it's collective behavior this is collective behavior in arthropods and the changing biota throws a real oddities we're not able to explain easily and it gives us a lot of thought as to how animal body plans are assembled together this is the eponymous genus called you nanos ouin after Yunnan Province and it is what you say what are these are these segments is it an arthropod are they muscle blocks is it a chordate is it a worm what are these holes here are they areas which some people have suggested for gills the takeout message here is that we don't know in many cases what some of the animals are we are still learning about their true affinity but here you have a case in point of animals assembling a peculiar body plant and that's important to try and determine what it is if we're to sort out relationships and evolution the generator is by no means the only exceptionally preserved biota in in the world from the lower Cambrian we have other exceptionally preserved fossils like this one we published four or five years ago now this is a millimetre long micro arthropod less than the size of a pinhead but all the appendages beautifully preserved including these epic pods and beautiful eyes all that in a pinhead same age as Chen Jiang Gregg Edgecumbe and colleagues at the Natural History Museum in Australia described beautifully preserved eyes hear from an exceptionally preserved biota in Kangaroo Island in Australia the EMU bass shale biota and these have beautiful lenses can you see the lenses in this compound eye to show that sophisticated vision was already in place in the lower Cambrian the chair gang by auto is very important not least it helps us try and address this question which actually a conference here in the Society addressed just what was it ten days ago unfortunate I was in America and couldn't attend but I gathered the meeting was exceedingly enjoyable one and this comes from a paper published in Nature by Doug Irwin and and company he would have geological time there is the Cambrian Precambrian boundary there and the chang-chang biota is that line there it represents a splurge this yellow splurge in the fossil record of taxa which then go on to give us the modern fauna we the Chiang biota a knowledge would have to jump up a little bit to the Burgess Shale middle Cambrian but here we have in Cambrian series 2 stage 3 the Chen yang biota of course the Cambrian radiation is one of the old chestnuts of paleontology is it fact or is it fiction did it really happen and if it happened why did it happen as I say a whole conference was held on that recently so I don't intend to open that debate here but Doug Irwin in his elegant paper in nature said that the developmental toolkit the genetic change is needed to assemble all these various forms of life came from the cryogenic from about 640 to 800 or so million years the developmental toolkit in terms of genes was assembled then and what we get here in the late Precambrian and I think my point has just gone dead on me well oh no it's there what we get in the in the higher part of the column in the Cambrian is in fact the ecological success story of the genetic changes that were occurring lower down in the geological record of course this man Charles Darwin scratchie said long and hard about the the Cambrian the so called can what we now call the Cambrian radiation and it was even more perplexing for him because he didn't have the benefit of knowing that in the Precambrian we have organic or micro fossils and the any Akron biota in in Australia to provide just two examples of a Precambrian fossil record the changing biota is a fallen marine shallow marine ecosystem and I just want to illustrate in the next two or three images how paleontologists also have snapshots of life on land not just in the marina environments but in terrestrial ecosystems this is what Aberdeenshire looked like about 390 400 million years ago this is the reconstruction of a famous paleontological locality called the Rani church it's effectively a siliceous hot spring which gave rise to exceptional preservation of early land plants here and early land animals offer ponds so here we have an intimate association not long after animals and land and animals and plants decided it would be a good idea to get out of the sea onto land here we have an intimate association a coevolution if you will of animals and early land plants and the Rani chert is not only important in giving us this snapshot of this co-evolutionary phenomenon but also he contains the world's earliest insects if we jump up the stratigraphic column then we can jump to this iconic fossil Archaeopteryx which of course there is a specimen in there in the Natural History Museum and specimens in Berlin and Archaeopteryx gives us one of those very important fossils which often are termed loosely missing links the skeleton is reptilian like but of course it contains feathers and once lauded as a bird we know know this to be a kind of what we call now in the trainer Dino bird it's a perhaps a dinosaur with feathers and this specimen is a famous one and even more recently Dino birds like Archaeopteryx which gives us information about the transition between two major groups of animals dinosaurs like Archaeopteryx similar I've been found in China in the Cretaceous of China for example this is one of them when I assembled they exhibition on t-rex in my department at Leicester the basis of my display was flying dinosaurs the evolution of flight and the birds and I wanted a diner bird to go in the exhibition you'll be surprised how much I was asked to pay for one and there's all kinds of legal and ethical reasons why I shouldn't purchase one so I had one cast but the vertebrate paleontology Institute in Beijing and then of course I wanted I said it'd be great idea to have a model one net of my Dino diet this is a Cretaceous diner bird the dinosaur with feathers I thought it'd be great idea to have a model and then the call came back from Toronto where I was having t-rex manufactured what color would you like your bird I've never really thought about that and I said oh gosh maybe off-the-shoulder pink or I don't know and this was when I was putting the exhibition together about four years ago now subsequently we have colleagues like Mike bent in Bristol and others who've published in Lerner journals that we can get pigments melanosomes they're called from Dino Birds and we can analyze these pigments geo chemically don't us we care because this not my field but we can analyze these these pigments do chemically and and work out what the color scheme of ancient vertebrates would be where these villainous arms are found I decided to have my Dino bird colored green and I hope you like it but you know if if if we if you were to find the line of psalms from this particular bird which is thought Confucianist after convolution the famous Chinese philosopher then maybe we find out really whether my green color was was right or not and here just one final terrestrial ecosystem is a very intimate association of a male and female spider they're trying to make love they're copulating and this is a 14 million million year old piece of amber preserved beautifully from tree resin in the Baltic and that of course is a moment though you couldn't hope to capture really in a fossil record but we do and it tells us stuff about social behavior and all kinds of things that we couldn't we couldn't dream about maybe some ladies have amber examine it carefully you might have you might have naughty spiders in it there's one period in geological history which is so far furnished not very many exceptionally preserved by Otis and this might be an accident for the monkey some real reason for it but it's a Silurian period of time in the lower Paleozoic and until the late 1990s we only had two or three almost apologies for exceptionally preserved by Otis in the solarium but then in the late 1990s a new one was discovered a Silurian aged not when not anywhere exotic but in the west borderland in the good old county of Herefordshire and here we are on site working on the Herefordshire biota with my colleagues derek Briggs from Yale they're exhibited from Oxford mark certain from Imperial College that's a team who've been working on this and this is their volcanic ash in ancient volcanic ash and in that volcanic ash we find nodules and he knows nodules we find lumps of calcite and it doesn't look much does it but that lump of calcite there is a fully three-dimensional soft bodied worm of mid Silurian age 425 million years old as soon as we realize that we can say cripes fossilization will speak very fast to preserve a three-dimensional worm and cripes if we've got a worm then we've got the chance of reconstructing the entire biotech because one would be one of the first things to go when you look down to microscopic fossils in these nodules the nodules are composed of calcite and quartz and clay minerals this is what they look like and I think everybody in this audience would say yeah that's a snail I can recognize the heli code pattern no problem but then what is this is that an arthropod are these legs what is this is it a worm are these segments the problem we faced as professional paleontologists is we could tell you briefly cursory what these might be but we had no real idea and the real problem is we can't grab the fossil out of the rock because there is no physical or chemical technique to grab the science grab the fossil from the rock we couldn't get it out so what we did was to destroy the fossil and we destroy the fossil by grinding away at 20 micron intervals and after each 20 micron grind we take a digital image and then we get all of these digital images in hundreds of them in some fossils and stitch them together this is what we thought was a worm you can see here the calcite course in the middle fine around the outside and let's hope the technology works we're grinding away this is a video file through that 40 millimeter fossil 20 microns remember there are thousand microns in a millimeter to give you some idea of scale so the fossil is gone but we have all the digital information and when we stitch that together this is the fossil it's not something I ever imagined I would see in my lifetime what we thought was a worm go seat over me fool and this is the head region which should attach onto Hunter there what we thought was a worm is in fact a mollusk of vermiform mollusk how many worms do you know with shells on the back you don't it has shells on the back spines throughout this area here is a cavity girls inside and this worm is a primitive world and it's telling us something fundamental about the relationship of primitive mollusks these aren't too primitive groups of mollusks this is a poly Clicquot forum it has many shells it's called chitin in general terms and this is an applic opera it's a mollusk without shells and what this fossil is telling us is we've got a an apricot foreign like body but with shells it's telling us something fundamental about the primitive state of these masks which we couldn't hope to get unless we've got an exceptionally preserved fossil we do have real worms bristle worms this is a polychaete again preserved in three dimensions we are familiar with bristle worms now school boy has ever carried a bucket and spade onto a onto a seashore as fail to find a bristle worm normally all we all we have in the fossil record of bristle worms is their jaw apparatus what microbiologist calls calico Dom's there are three or four examples through the stratigraphic record where we have some body parts of Polly Kate's bristle worms but they are exceedingly rare and nothing achieves this level of detail with all the mouth parts here and various parapodia along here including the extensions which are break here gills for breathing it's an exceptional preservation and giving us an insight into the evolution of this essentially soft body Groot we do have snails this is what good sea looked like in the rock good sea turned out to be a snail and here we have the anus the intestine the stomach the head foot region including the radula here in in orange interestingly we haven't got the dustbin lid the operculum which you know closes the trap door and protects the soft parts and with this level of preservation we should have in a particular in that gastropod so maybe this gastropod lives like some of its modern relatives it has no a perk ulam and if tacit attaches onto other animals like a karna domes for protection and also to grab some some of their food it's the only known gas supporting the Paleozoic with soft paths and an early crown group mollusks with soft pods which is very rare we have black ear pods and this was it in the rock and this projection turned out to be a pedicle and it tells us that this particular brachiopod has a real physical tether onto the substrate or the object to which it's attached it's not like a modern brachiopod which has properly for chemical resorption this is like a boat being mauled on the side and it's an important lesson it tells us not to take what we know from the modern record and interpret the fossil record as being the same because it's not this is a beautiful animal and it's got epi biomes attached to it it's got black ear pods on brachiopods so we've got a nice little paleo ecological story here and if I had time we could dice that and show you the the lava for inside this is the first fossil we found here for chair and it's stemming because it's only six millimeters long but it's beautiful with all these appendages here and gills at the bottom this is what we called offer colas because the locality in Herefordshire is not too far from offers died so offer colas is a kind of iconic fossil and as I say from tail to head six millimeters and what you're looking at here is an early example of lineages which led to the - the king crab the modern Lynn - aware about how these things were preserved and this is a little bit of geochemistry but this is offer colas and we are doing microprobe analysis here for calcium and here we've got an enrichment of calcium inside the fossil and a depletion outside the fossil in the nodule and we think that the calcium to form the calcium in calcium carbonate the calcite which preserves this animal we think the calcium was sourced from from the nodule and maybe the bicarbonate was sourced from the decay of of the animal there's also clay minerals which sort of template the fossils around the outside so this was a kind of working model we published petiole who was a postdoc at the time in the john sock joseph publication volcano set off submerged and smothered animals then the animal started to decay but at the same time an envelope of clay minerals went around the outside and then this is the point which we really haven't cracked how do you preserve a three-dimensional fossil and quickly infuse calcium carbide in it and just preserve it like that in a snapshot of time before you get collapse very difficult we have PhD student David Riley at Leicester who's hoping to provide some of the answers but it's very difficult then the the nodule formed we think the nahji was almost penny contemporaneous with the formation of calcite and the larger of course gives you the long-term preserve ability of the fossil itself we have ever arthropods this was strongly straggly was all the Flying Fortress as it was sometimes call was was in our collections for several years we had one specimen we don't like to send a specimen to the guillotine unless we've got two specimens for obvious reasons but in the end our frustration over became the better of us and when we reconstructed it was a sylua inspired our picnic on it and modern picnic garnets like this one of course a very common in modern seas from the Arctic to the tropics I found that several thousand meters depth they're very rare in the fossil record there are a few examples of the Devonian the hunt rocks late in Germany the bits and pieces in the Cambrian the Austin in the Baltic but really this is the best preserved fossil peak Nago need we have from the fossil record hampi turned out to be a mullah costigan you can see what we call the tongue feed that was the shell humping was a malik austere cone it's a relative of the shrimp and the lobster in the crab beautiful developed appendages beautiful eyes here at the front and trunk' was a revelation because we had two specimens of trunky and it turned out to be nothing less than a Silurian barnacle but two stages in the life cycle of a sign living barnacle this is the free living larval stage and when barnacles decide they want to grow up and settle down they put their head this area here on a rock the peduncle and then secrete shells around five calcitic shells and they become big the life cycle of a barnacle hasn't changed in 425 million years and here we have a nice little example by erosion and this is a famous fossil for many reasons or I should almost say infamous fossil this is this is horny and horny because of these whole nine projections turn out to be a micro arthropod and ostracod there any of you who've got plans or lakes or rivers near your homes have ostracods there at the communists form of arthropod in the fossil record they are present in their cancer that countless thousands of species today and here we have a full five millimeter lung Silurian ostracon and when we dissected virtually we have all the appendages we have the first appendage the second appendage the mandible the third fourth and fifth Defenders is this is a seventh and this is a gills and here we have incredibly the penis preserved so you're looking at the world's oldest valley calling and the general body plan of this silo in ostracod is exactly the same as that modern counterpart from japan here's the penis there there are the gills and so on the basic body plan hasn't changed in this group over all those millions of years and just what this one find extended back the paleo biology or our knowledge of this group by more than 200 million years and of course we've got the old the world's earliest male here if you will and that the world's media of course had a field day with this I won't give any prizes for guessing which celebrated English newspaper this this came from but my favorite is in the headline in the New York Times which said yes it's definitely a boy it was enormous fun and the media went viral for about two weeks but of course we are looking at an important scientific find here because it's a verifiable mail 425 million years old and then of course the quest was on to find a female and we indeed did find a female not of the same species but this is another ostracod from Herefordshire and if we dissect it virtually which you can do because that's what we're about everything here is virtual fossils and stop it there here posteriorly we have a juvenile and eggs and it has the same brooding strategy as the modern equivalent ostracod brute care of the young was occurring in the same way in this group of arthropods 1425 million years ago and there are others which I don't have time to tell you this is a Marella morph again from Herefordshire Marella of course is about an iconic fossil from the Burgess share and here we have a Siberian Marella morph beautifully preserved with all the appendages in the head and a set of 35 appendages in the body giving us immense detail telling us that Marella morphs probably cousins of a large group of arthropods called the mandibular which include the Crustacea and the hexa Ponce and the myriapods so we're putting together this Herefordshire biota now and this is what it's looking like I mean this is exciting this is what paleontology is trying to do we're trying to re-establish reconstruct an ecosystem it's not Jurassic Park it's a Silurian marine equivalent we're looking at a Silurian seascape and all of these animals exist on them and we've published most of these now and some to be published this thing here is a genus of ostracod called Pauline which we beautiful ostracon another ostracoda which we which we published before Christmas in the Proceedings of the Royal Society and of course because we've got this information digitally that's wonderful we were fortunate enough to be accepted to exhibit at the Royal Society summer exhibition a few years ago and we thought well we want some baubles and of course because we've got the information digitally we can take it along to a rapid prototype laboratory and overnight they will sync tear out and models sitting on Siberian sand if you will so this is spiny this is Harry this is leggy all reconstructed and remember these aren't sort of reconstructions in the sense that their model recon so because these are real individual animals that lived on a seabed warts and all because they they are assembled from real data from individual fossils just to give you a flavour to finish off these are some of the animals which we've just published or almost on the point of publishing this is another armored apricot run which we published just before Christmas last year in the in nature this is a new sort of king crab relative which we again we published in the Proceedings of the National Academy of Sciences and just to give you something to think about what's that toilet brush I mean what is it it's almost defying belief but that's a real animal and what's this just to show you how exceptional this preservation is these CT are no more than 10 microns thick and they come from the end of the head and they go the length of the body and they are just frozen in time they are not collapsed they are not damaged in any way so dandy and pretty will appear on a new stem near you in the in the future but this is the game we're playing we've had this fossil there for many years this fossil what is it are these antennae are these legs is this a tail could it be that this Herefordshire fossil is the equivalent of a velvet worm is this an Omega for maybe could be possibly perhaps we won't know until we destroy it I'll finish by saying this fossil fauna in Herefordshire was preserved in the volcanic ash and we should ask the obvious question where did the ash come from now for those of you who know about volcan misti in the geological column there ain't much volcana city in mid solarium times in england and wales there's a lot for example in the Czech Republic but the Czech Republic at the time was speaking of was thousands of kilometers away across an ocean that's not to say that volcanic ash doesn't travel it does so he could be that the Czech Republic was responsible for the Vulcan isset II which gave us this exceptional biota but the obvious candidate actually is near a home some of you might recognize this beautiful landscape this is the dingle peninsula in southwest ireland so if you jump up here and start to swim the next stop is New England and here you've got solar deposits of the right age with volcanic rock of the right type to give us the ash and this was not too far away from her future at that time we're speaking man so maybe just maybe we have to really clap our hands and thank I refrain for the volcanic ash which which gave us this wonderful exceptionally preserved by out now I'm sure with some questions the I couldn't with you touched on this really but how quickly would what are we talking about days minutes hours would it take to fossa get the least deserved yep and secondly wild some of them in a state of decay that are fossilized both are very good in elementary questions in terms of the timing we can do some actual paleontology and look at decay rates we can actually get animals in the lab and see how they decay but you don't need to be a scientist and have a live orator to do this if a worm dies in your garden tomorrow within 24 hours the body fluids have oozed out and you've got a two dimensional animal not a three-dimensional animal so just intuitively the hole fits your biota for example has to be preserved like that almost instantaneously it's just going to be frozen in time that was the pointer I made with this this thing here is got no distortion no decay whatsoever so it has to be instantaneous inrush of the mineralization to preserve the three dimensionality it also probably has to be smothered rather quickly so that scavengers can't actually pray on it all of these factors probably paid apart sorry the second point was because because I think I think they were there that they were in the case of Harry be sure they were mineralized very quickly and smothered and incorporated into the module very quickly we know from geochemical work that the nodule formation was probably almost pini contemporaneous with the formation of calcite to preserve the three-dimensionality of the fossil itself and undoubtedly the nodule then preserved the long-term prospects of the fossil so was there something in the Cambrian or early Paleozoic that kind of allowed this exceptional reservation that's been the subject of papers by other colleagues particularly their Cambrian the Cambridge group and it seems as if Indyk and Rhea and the the was widespread anoxia which helped to preserve animals immense exceptional preservation comes about through a number of factors one is in entrapment in some way an animal is preserved in ice or pickled in some way or mummified in some way an animal is smothered very quickly that also helps and if animals die and are preserved in anoxic environments reduced oxygen conditions that also cuts down microbial decay so in the Cambrian II it's thought that anoxia was widespread in some areas and at some times and this probably helped also there's a question of bioturbation and it seems that bioturbation animals going through the the mud was an increased factor in the Ordovician and to some extent that may have been responsible for cutting out the taphonomic window which is present in the Cambrian because heaven knows the cambrian has more than a respectable share more than its fair share of exceptionally preserved by Otis if you had a choice where would you like to find a large nut in the future yeah I mean it's it's one of the nice things have had a paleontologist job that whenever you go out into the field you don't know really what you going to find all the blockbuster loggers Ted was you know chanced upon by by accident I mean legend has he that Wolcott was riding his horse and stumbled across a block and got off and there was a burgess shale fossil the chenggang biota it's one of the blockbusters least equal to to purchase by the way we helped to to write the Chinese government application to make Chen Django a world heritage site and it achieved that status in some Petersburg UNESCO approved it as a world heritage site last year when when I go anywhere there is field work to be done the Herefordshire fauna was was was discovered in a way by chance and some diligence it's serendipity and where would I like to go I mean I'm been to China I've been to her if a chair the ross borderlands as a place in my in my heart anywhere there are fossils that's our business a few years ago there was a thought perpetrated in china i think it was a bird fossil yeah it was very well done and for people for some time yes are you concerned that this is still going on yes i know that you're talking about and of course it brought huge disrepute on to the individuals and institutes involved and that was unfortunate i'm not concerned that we have any such incidents with chang-jung what they did in that case was effectively fabricate different pieces of be interpreted and put them together but this is not a new activity Victorian paleontologists were doing this with ammonites in order to sell them for financial gain you'll do moons yes exactly so the answer to your question is it's unfortunate and it really shouldn't happen these days but where finances are concerned it does happen I mean you know the asking price when I went to try and buy a dino bird and I thought well maybe ethically I can't do it you can't no Chinese have stopped all export in theory yet there shouldn't be a changing fossil outside China there shouldn't be a Chinese vertebrate outside China but if you go to the Tucson rock and mineral fair which has occurred recently in America there are dealers that will sell you them but when I inquired four years ago could I have a dino bird for my exhibition the asking price was thirty thousand so it's big money and it's not easy to see how you know poorly paid Chinese people who work on the land would see a way of I say Chinese it could be Westerners over encourage them it's not easy to it's easy to see the way that this could happen but no Chiang fossils are checking fossils they're not fabricated Herefordshire fossils are virtual fossils so you might you might say a fabricated but they so does exceptional preservation of soft material only happen in fine material like shales and what kind of cache or does happen in coarser material as well it can't happen be in coarser material but of course if you're going to get the fidelity of detail which I've demonstrated hopefully tonight then you need fine material to truly replicate the original morphology but you can get you can get exceptionally preserved by Otis in course of material for example the famous Ediacaran biota of late Precambrian age is in sandstones some of them relatively coarse sand stones but you have got soft and fragile soft bodied fossils preserved so it helps but it's it's not absolutely necessary if it's fine fine sediment well the doors are closed there we have a glass of wine are waiting at Southside it sounds great they thank you very much for your wonderful lecture I think you want these up this is the Pompeii of Herefordshire

Channel: GeologicalSociety

Views: 14,740

Rating: 4.8596492 out of 5

Keywords: Fossils, Evolution

Id: IDm4yYaAvZM

Length: 69min 48sec (4188 seconds)

Published: Mon May 20 2013

Reddit Comments

[u/alllie]

March's Shell London lecture, delivered by David Siveter (University of Leicester) at the Geological Society on 27 March 2013.

Our understanding of the history and evolution of life on Earth relies heavily on the fossil record and especially on rare cases of so-called 'exceptional preservation', where the soft parts of animals and entire soft-bodied animals are preserved. Such exceptionally preserved fossils provide unique insights of animal palaeobiology and the true nature of biodiversity.

The lecture illustrates beautifully preserved fossils through geological time. It focuses especially on spectacular finds from two of the world's most important fossil assemblages, from 530 million year old rocks in China and 425 million year old rocks in the Welsh Borderland. These deposits contain a wide range of marine animals that lived on the sea floor and in the water column, including sponges, worms, starfish, snails and other molluscs, arthropods of various kinds and the earliest known vertebrate. The fossils from the Welsh Borderland are being studied by tomographic techniques, resulting in the reconstruction of high fidelity three-dimensional 'virtual fossils' that furnish remarkable anatomical details of the animals. Such fossils are crucial in helping to fill gaps in our knowledge of the history of life and in helping resolve controversies about the relationships of animals still alive today.