Arthur the Arthropleura Lucy McCobb, 23 March 2022 Who is Arthur the Arthropleura? Arthur is a model of the biggest invertebrate that has ever lived on land, a millipede-like creature called Arthropleura. Where did Arthur the Arthropleura come from? The model was originally on display in Kew Garden’s Evolution House but when the space was dismantled in preparation for the HLF funded restoration of the Temperate House, it was no longer needed and Kew kindly donated it to Amgueddfa Cymru – National Museum Wales. The Arthropleura model was in need of some substantial conservation work when it arrived at Amgueddfa Cymru – National Museum Wales. It had been on open display for many years in a glass house alongside living plants and was damaged and rusty. The humid display environment had caused the surface paint to flake away and several spiders and snails had taken up residence on the underside of the model! Arthur the Arthropleura before conservation The first job was to give the model a good wash with hot soapy water and remove the dirt and cobwebs! Arthur the Arthropleura has a bath Then all the flaking paint was scrubbed off, the damaged areas on the legs and head were rebuilt with an epoxy putty and the surface textures recreated. The nuts and bolts of the removable antennae had rusted together, so the metal parts were replaced with new stainless steel threaded rods. Once the repairs were complete the model was carefully painted with acrylics and then coated in a durable varnish, making it once again suitable for public display. Arthur the Arthropleura after conservation Who named the Arthropleura - Arthur? Some of the Natural Sciences staff had become rather attached to the impressive 1.5m long millipede model whilst it underwent conservation work in the lab and named it Arthur the Arthropleura. We have also had fun with Arthur; he has “escaped” and been on the run around the museum galleries! Arthur the Arthropleura visits the Impressionists We posted pictures of his adventures on the @CardiffCurator Natural Sciences Twitter account and had a fantastic response from our followers. Arthur the Arthropleura is now a social media star and is a really wonderful addition to our collections! What did Arthropleura look like? Arthropleura looked a lot like millipedes do today. It had a long, narrow body made up of lots of segments, and its back was covered in hard plates. On the underside of the body, there were lots of pairs of jointed legs, around 8 pairs for every six body segments, which is similar to the number of legs modern millipedes have. Recently, palaeontologists realised that what they had previously thought was the head of Arthropleura, is actually just the front segment of its body. The head was tucked underneath this segment, just like it is in millipedes today. So our model Arthur is a bit out-of-date, and he shouldn’t be looking straight ahead quite as much as he does. How big was Arthropleura? There are two types of evidence that tell us how big Arthropleura was. Fossils of the animal’s body, or parts of it, have been found in Germany, Belgium, France, the Czech Republic, and the U.K., but these are relatively rare. More common are fossils of the long trackways made by the many feet of the Arthropleura as it scuttled over damp ground. Its fossilised footprints are known from the USA, Canada, Germany, France and Scotland. Measuring the trackways tells us how wide the animals that made them must have been, and we can calculate from that how long the animals likely were. Arthur the Arthropleura next to a fox for size Some places have several trackways in different sizes, showing that different sized (and probably aged) Arthropleuras were moving around in that area. The widest trackway known is 50cm wide, and the biggest Arthropleura is estimated to have been over 2m long. Where did Arthropleura like to live? Arthropleura fossils and trackways have been found in various locations that would have been fairly close to the equator 300 million years ago, including modern-day North America and the U.K. Many of the first fossils were found in roof shales overlying coal seams, so it was thought for a long time that the giant creepy-crawlies just lived in humid coal swamps. Since then, evidence of Arthropleura has been found from a wider range of environments, including footprints walking along drier river banks. It appears that they felt at home in a variety of landscapes with some vegetation cover. Would Arthopleura have eaten me? We can’t be certain what Arthropleura liked to eat, because its mouthparts have never been found in any fossils. However, if it did have tough, strong jaws for biting prey with, they would probably have survived and become fossilised. That may be circular reasoning, but there are other reasons why we think it probably ate plants rather than meat. An Arthropleura fossil was found in Scotland in 1967, which had the remains of plants called giant clubmosses in the area where its gut would have been. It’s possible that the fossils were just preserved together by accident, so we can’t be certain the plants were actually Arthropleura’s last meal. However, if its diet was similar to that of modern-day millipedes, it is likely to have lived on plant remains, seeds and spores. Which other animals did Arthropleura share its home with? If you looked around at the animals that shared Arthropleura’s world, you would see a very different view of life from today. There were no birds or mammals, because they hadn’t evolved yet. Scout around for our nearest relative, and you would eventually spy, lurking in the water, a large, squat amphibian called Eryops. Animals with backbones were yet to gain a dominant foothold on dry land. Instead, creepy-crawlies accounted for most of the life you would have seen around you. There were large cockroaches (up to 9cm long) scuttling around, and spider-like creatures that would fill the palm of your hand. These weren't exactly like modern spiders - their fat bodies were divided up into segments rather than consisting of a single rounded piece, and they hadn't yet evolved the ability to spin webs - but they were well on their way to becoming the arachnids we see today. fossil of a primitive spider-like creature (Maiocercus celticus) The air would have been filled with a distinct hum from the most awesome animals around – huge dragonfly-like insects called griffinflies, whose wingspans could exceed 70cm. Griffinflies were among the top predators of their day, and were some of the first creatures on Earth ever to fly, around 150 million years before the first birds took to the wing. Even our amphibian kin Eryops had to share its home with arthropods; horseshoe crabs that also liked to divide their time between dry land and water. Why don’t we get such huge invertebrates on land today? The Carboniferous Period, around 300 million years ago, was undoubtedly the era of huge invertebrates. At that time, giant Arthopleura, the biggest creepy-crawly that has ever lived on land, was joined by large cockroaches, arachnids and dragonfly-like insects. How was that possible, and why don't we see invertebrates as big as Arthur today? Our atmosphere has around 21% oxygen. The evidence suggests that 300 million years ago, oxygen levels approached 35%. That would have made a huge difference to the amount of energy that insects and other arthropods could generate. Insects and millipedes don't have lungs to actively breathe in air like we do. Instead, their exoskeletons have lots of tiny tubes passing through them called spiracles. Oxygen diffuses in through the tubes from the outside into a blood-filled cavity, from where it gets distributed around the animal's body, fuelling everything it does. More oxygen available meant more fuel, which enabled creepy-crawlies to grow bigger, and which would have been especially important in generating enough energy to get large flying insects off the ground. Such giants could not get airborne under today's atmospheric conditions. Arthur in one of his natural habitats, the coal swamp in our Evolution of Wales gallery Oxygen levels aside, there are mechanical limitations to having an exoskeleton, which make it unlikely that such large invertebrates could exist today. In order to grow bigger, all arthropods need to moult off their old exoskeleton and grow a new larger one. There is a period of time after moulting when the new exoskeleton is soft, and the arthropod must wait for it to harden before it can carry on with its normal life. Not only is this a dangerous time when the animal is vulnerable to predators, but it places a limit on size – if the exoskeleton becomes too big and heavy, it risks collapsing under its own weight. That is one reason why the largest arthropods today live in the ocean, where the water helps to support their weight. There is also a limit on how big creepy-crawly legs can get, as the bigger they get, the thicker the cuticle they're made of becomes. They can only get to a certain size before the thick cuticle doesn't leave enough room inside for the muscles needed to operate the legs. Another factor allowing Arthur and others to grow so huge may have been the lack of large vertebrate predators. For a variety of reasons, it just isn't possible for such giant creepy-crawlies to exist today. Lucy McCobb, Caroline Buttler & Annette Townsend Glossary: Arthropod – an invertebrate animal with a hard exoskeleton and jointed limbs. Invertebrate – an animal without a backbone. Exoskeleton – a tough outer skin, which provides support and protection to animals without an internal skeleton.
William Smith and the Birth of the Geological Map Tom Sharpe (Lyme Regis Museum and Cardiff University, former Curator of Palaeontology and Archives in Amgueddfa Cymru – National Museum Wales), 30 November 2015 Geological maps are fundamental tools to a geologist. Displaying the distribution of different types and ages of rocks, they are the first step to understanding the geology of a place and key to the search for raw materials. Today, the whole of Britain has been mapped, largely through the work of the official agency, the British Geological Survey. But two hundred years ago, geology was a new science and the Survey was yet to be established. The industrial revolution was in full swing and the demand for coal, iron and limestone was huge. Landowners, keen to find coal on their properties, were being exploited by itinerant surveyors who, through greed and ignorance, persuaded them to fund searches where coal was never likely to be found. William Smith, a surveyor from Oxfordshire, realised that a map showing where different rock layers - strata - came to the surface would be of value to both landowners and surveyors, not just for locating coal but also for agriculture, showing the different rocks and hence soils of different types. It would take him almost 15 years to complete. Smith was born on 23 March 1769 in the Cotswold village of Churchill where his father was the blacksmith. He had a limited schooling but at the age of eighteen he was taken on as an apprentice surveyor in the practice of Edward Webb in Stow-on-the-Wold. He showed an aptitude for measurement and mathematics and an eye for the shape of the land. In 1791 Smith was sent to survey and value coal mines in the Somerset coalfield south of Bath, and two years later was appointed to survey the route for a new canal to transport coal from the mines. Discoveries During the six years that Smith worked on the Somerset Coal Canal, he made two fundamental discoveries. The canal was to be constructed in two branches in adjacent valleys and Smith noticed that the sequence of rock layers was not only the same in each valley but that the layers were always tilted towards the southeast. During his travels around the country to examine other canal routes, Smith realised that the strata of southern England always occur in a regular order and all were tilted in the same direction. His other discovery was the realisation that certain fossils were associated with particular strata; this meant that he could use the fossils to identify where a layer of rock lay in the sequence of strata. The practical application of these discoveries was immediately obvious to Smith. Coal occurs in association with grey mudstone rocks, but such rocks appear in several places in the sequence of strata, both far below and above the coal. Using fossils, Smith could identify which grey mudstones were part of the coal beds and which were not, and with his knowledge of the sequence of strata, Smith could construct a map showing where the different rocks were present at the surface and where coal could be found. When Smith explained his work to his friends Joseph Townsend and Benjamin Richardson in Bath on 11th June 1799, they persuaded him that he needed to publish his discoveries in order to receive credit for them and, possibly, reward. That evening, he dictated the order of the strata to his friends and soon handwritten lists of the sequence of rocks from the coal up to the Chalk were in circulation. Soon afterwards, Smith sketched a map showing the rocks of the Bath area and a small map showing some of the rock outcrops extending across England. In 1801 he published a prospectus of his intended great work on the strata of England and Wales. Over the course of the next fifteen years, Smith travelled widely across the country, working on commissions as a land surveyor and drainer. As he travelled, he took note of the landscapes and the rocks, gradually accumulating the information he needed for his map. Publishing the Map The map was eventually published late in 1815 by John Cary, a leading London mapmaker. A Delineation of the Strata of England and Wales, with part of Scotland was a monumental work. At a scale of five miles to the inch, it was huge, over eight feet tall and six feet wide. It was spectacularly (and expensively) hand-coloured. It sold at prices starting at 5 guineas for the map in fifteen sheets, plus an index map and an accompanying Memoir. But although Smith’s Memoir listed over 400 subscribers to his map, few had paid in advance, and as his map had taken so long to complete, some of his subscribers had died. We do not know how many maps were sold, but it may have been in the order of only about 350. During the years of its production, Smith continually altered the map as new information about the distribution of the strata became available to him and there are at least five different issues of the map known. Within five years, Smith’s map was eclipsed by another, in places more detailed, map, the product of the collaborative effort of members of the Geological Society of London under its first President, George Bellas Greenough. And within twenty years of the publication of Smith’s map, detailed geological mapping came within the remit of a new, government-funded Geological Survey of Great Britain. Smith’s beautifully-coloured map, however, remains an icon of the science of geology and is widely regarded as the first true geological map of any country. It also the more remarkable in that it represents the work of one man, who single-handedly mapped, for the first time, over 175,000 square kilometres of Britain. Today the map is much sought-after by collectors and commands serious prices (currently there is one for sale in London for over £90,000). The number of copies still extant is currently being researched, but it is likely to be in the order of 150. The Department of Geology (now Natural Sciences) in the National Museum of Wales is in the unique position of holding nine complete or partial copies of the map, more than any other institution in the world, thanks to the foresight of its first Keepers, Frederick J. North, Douglas A. Bassett and Michael G. Bassett. North, in particular, rapidly established the Geology Department’s map and archive collections as one of the most important in the country and this has been built upon by his two successors. The National Museum is the only place in the world where almost all of the different issues of the map can be examined side by side. A version of the article was published in Earth Heritage.
Museum Type Fossils Online Caroline Buttler, 8 April 2014 Anthracoceras cambriense Bisat, 1930 Bumastus? xestos Lane & Thomas, 1978 Metacoceras postcostatum Bisat, 1930 Archimylacris scalaris Bolton, 1930 When a new species is described a single ‘type’ specimen is identified, which is then deposited in a recognised organisation and made available for anyone to study. These type specimens become the essential reference for taxonomists, both when describing existing species and erecting new ones. Without type specimens it would be hard to keep the integrity of a species, and over time the taxonomy could drift so that subsequent species interpretations would not bear any relationship to the original one. GB3D Type Fossils Amgueddfa Cymru has joined with the British Geological Survey and other UK organisations to produce the world’s first 3D virtual collection of British fossil type specimens, funded by JISC. Thousands of high quality images, many as 3D anaglyphs, and spectacular 3D digital fossil models can now be browsed and downloaded for free. The GB3D Type Fossils Online project has taken the fossils from their stores and made them available for academics, researchers and fossil enthusiasts to enjoy at their leisure. Our British fossil type collection of over 2000 specimens forms a very small proportion of our total collection of fossil specimens from Wales and the rest of the world. Researchers from Wales, the United Kingdom and world-wide use the collections to support their taxonomic research. Palaeontologists at the museum have named many new species of fossils and have sometimes had fossils named after them. For them and for all taxonomists it is essential to have access to type material. If you are dealing with a potential new species, ideally the actual type specimens of similar looking species should be examined, but this is not always possible, due to travel costs, for example. When a new species is proposed it is described in a scientific journal and the type specimen is photographed. However, in old publications some types have not been illustrated, and in some publications the images may be of poor quality making it hard to determine specific features of the specimen. Therefore this new digital resource will be invaluable, illustrating the British type collection in high-resolution 2D and 3D images, in addition to 3D models. The freely available website will also provide worldwide access to our collections. See the website here.
Trapped in Time Trevor Bailey, 26 February 2014 Fungus Gnat (Sciaridae) These small animals look like they died yesterday, but they are actually about 50 million years old. A student on work experience at the Museum used new software to image our amber collection. Using a microscope, photos were taken from different depths inside an amber sample. The in-focus parts of each photo were then merged to create a single clear image. Windows on an ancient world These animals died after becoming trapped in soft sticky resin produced by conifer trees as protection against fungal infection. When the trees died their resin was buried underground in layers of vegetation and sediment - eventually becoming hardened by pressure and heat to form amber. Most of our amber comes from the Baltic Sea region. The trapped animals include ants, aphids, beetles, flies, gnats, harvestmen, moths, nematode worms, spiders, and wasps. These forest creatures lived at least 50 million years ago in the Eocene epoch. This was a time of greenhouse climate which was much warmer than today due to higher levels of carbon dioxide in the atmosphere. There’s also a wasp preserved in amber from Cretaceous sediments of New Jersey, USA – which makes it old enough to have seen the dinosaurs! Looking after amber We store our amber in air tight containers in a room where the temperature and amount of water vapour in the air (humidity) can be controlled. If amber is exposed to rapid swings between too damp and too dry, tiny cracks can form, and these windows to the past can be broken. Trapped in Amber Fungus Gnat (Sciaridae) Ant and Spider Spider Fungus Gnat (Sciaridae) Fungus gnat (Sciaridae) Biting Midge and Moth Wasp, possibly Stigmaphronidae Beetle True Fly (Diptera) True Fly (Diptera) Fungus Gnat (Sciaridae)
Golden Wonder! Rare fossil trilobite preserved in stunning detail Lucy McCobb, 2 August 2013 A tiny Triarthrus eatoni specimen lies next to the bigger one. Trilobites of various ages were fossilized together and must have lived in the same place. Only larvae are missing. Trilobites are common in the rocks in Wales, but this rare specimen differs from others in our collection. Preserved beneath the carapace are the legs and on the head a pair of delicate antennae ('feelers'). These features stand out vividly in gold against a black shale background. Such exceptional fossils give us great insights into how trilobites moved, fed and sensed the world around them. All trilobites had legs and antennae when they were alive, but these were quite soft and usually rotted away before they could be fossilized. Most trilobite fossils are just parts of the hard exoskeleton or carapace and tell us little about the softer parts of the body. Why is the trilobite golden? The golden colour is because the animal has been fossilized in pyrite, also known as iron pyrites or Fool's Gold. Fossilization of soft body parts in pyrite is very rare, and is only known from a couple of places in the world. This particular fossil comes from rocks of Ordovician age (approx. 455 million years ago) from New York State in the USA. Soft-bodied fossils preserved in pyrite are also found in the much younger Hunsrück Slate in Germany, of early Devonian age (approx. 390 million years ago). Pyrite is an iron sulphide mineral (FeS2), and it can form where there are low oxygen levels and lots of iron. The trilobites were probably swept up by an underwater avalanche and buried in deep sea mud. The mud would have been rich in sulphates and dissolved iron, but low in oxygen. Sulphate-reducing bacteria would have helped decay the trilobites, releasing sulphides. The sulphides combined with the dissolved iron to form pyrite, which replaced or coated the trilobite tissues as they decayed. The Museum's golden fossil from Martin Quarry, New York State. Larger trilobite approx. 3 cm long Beecher's Trilobite Bed Pyritized trilobites have been known from the famous Beecher's Trilobite Bed in New York State for over a century. The bed was discovered by amateur fossil collector William S. Valiant in 1892, but is named after Charles Emerson Beecher, an academic from Yale University to whom Valiant showed his amazing trilobite finds. Beecher leased the land between 1893 and 1895, and quarried out as many fossils as he could, until he thought there was nothing left to be found. He wrote many scientific papers about the trilobites until his untimely death in 1904. The trilobites were found in just one thin (4 cm) layer of rock, laid down around 455 million years ago, during the Ordovician period. C.E. Beecher's 1893 reconstruction of Triarthrus eatoni based on fossils from his Trilobite Bed. The legs have two branches, an inner walking leg and an outer gill with fine filaments. The Trilobite Bed was rediscovered in 1984 and since then, more beds containing golden trilobites have been found in New York State. In 2004, an amateur collector started searching about 50 miles away, and eventually found a rock layer of the same age containing trilobites. Our specimen comes from this new quarry, now known as Martin Quarry after its finder. Many important fossils have been found in Martin Quarry and studied by Professor Derek Briggs of the Yale Peabody Museum, and his colleagues. Growing Up Our specimen (Triarthrus eatoni) has a second, tiny trilobite next to the larger one. Trilobites grew from larva to adult by going through a series of moults. As they got older, they regularly moulted off their old exoskeleton to grow bigger. Many different sizes of Triarthrus have been found in the Trilobite Bed, but none of its earliest larval stage. Trilobites of various ages clearly lived together, but the larvae must have lived somewhere else. They may have floated around as plankton in the water column, while larger juveniles and adults lived on the sea bed.
