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.
The Long Reach of the Ghost Slug Ben Rowson, 11 August 2014 An adult Ghost Slug, about 7cms long. The Ghost Slug's blade-like teeth, each about half a millimetre long. These are much longer and sharper than those of herbivorous species. Close-up of the Ghost Slug's head. The eyes, if present, would normally be at the tips of the two upper (longer) tentacles. Verified Ghost Slug records received until Autumn 2013. The bizarre Ghost Slug made headlines in 2008 when described as a new species from a Cardiff garden. When the first specimens were found, very little was known about this animal. The story since then connects our collections and specialist expertise with sharp-eyed members of the British public, recording networks, other taxonomists in Europe, and the media to show how a picture is emerging. The species Emphasizing its spooky nature, we gave the species the scientific name Selenochlamys ysbryda, based on the Welsh word ysbryd, meaning a ghost or spirit. The common name “Ghost Slug” soon became popular. Identifying it with the obscure genus Selenochlamys was a specialist task and required dissection of several specimens including our holotype. (Incidentally, Selenochlamys already combines the Greek words for a cloak, and Selene, goddess of the moon, but “Moon-Cloaked Ghost Slug” sounded a little too melodramatic.) The Ghost Slug is strange in many ways. It is extremely elusive, living up to a metre deep in soil, only rarely visiting the surface. It seldom occurs in large numbers. This makes it an unusually difficult slug to look for, especially in other people’s gardens or other places that cannot be dug up. It is also very distinctive. After having examined one, most agree that it is unmistakeable in future (haunting, perhaps?). The slug is ghostly white, and almost eyeless. It does not eat plants, but kills and eats earthworms, whose burrows it can enter with its extremely extensible body. This differs from that of most other slugs in having the breathing hole right at the tail, and in retracting like the finger of a glove, appearing to suck its own head inside-out. Unlike some British slugs, it can be identified with certainty from a good photograph. The photos here show some similar species often confused with it. This combination of being elusive and distinctive makes the species perfect for a public recording project. We needed to know more, not just out of curiosity, but because the species might pose a threat to earthworm populations. It appeared to have been introduced from overseas, i.e. to be an alien or non-native species, whose spread might cause concern. We thank the then Countryside Council for Wales (now part of Natural Resources Wales) for funding early survey work and information dissemination in 2009, and others who have spread the word. Contributions from the public Since 2008, responses from over 300 people all over the UK (and a few from overseas) have been received and replied to. A large proportion were misidentifications, but many were correct and over 25 populations of Ghost Slugs are now known. These verified records have been submitted to the National Biodiversity Network via the Conchological Society of Great Britain and Ireland. We thank all respondents for their efforts, without which almost none of the populations would have been identified. As the map shows, the Ghost Slug is widespread in south-east Wales, occurring in all the main Valleys and in the cities of Cardiff and Newport, and at two sites in Bristol. It remains, however, rare or absent in some nearby areas (such as Swansea) and by no means occurs throughout this region. Virtually all the records are from gardens, allotments, or nearby roads and riversides in populated areas. This is also true of an unexpected outlier, reported in May 2013 from Wallingford, Oxfordshire, which might indicate an eastward spread. The species is evidently firmly established in Britain and has survived the unusually cold, dry, or wet winters of the last five years. Contributions from specialists This species has had at least 10 years to be spread around Britain, but has not yet been seen elsewhere in Western Europe. The earliest records are from Brecon Cathedral in 2004 (in a 2009 paper by German-based taxonomists) and from Caerphilly in 2006 (on a pet invertebrates forum). We expected its origin to be in the Caucasus Mountains of Georgia and Russia or in northern Turkey, where other Selenochlamys occur. However, a 2012 paper by a Ukraine-based taxonomist described a museum specimen of S. ysbryda collected in Crimea in 1989. This makes some sense – Crimea has a number of endemic molluscs, and several alien species now in Britain were originally described from the region. The UK also has a history of conflict and trade with Crimea (there is even a Sebastopol near a slug population in Cwmbran!) making a direct, accidental introduction plausible. DNA was sequenced from six specimens of the Ghost Slug, from Cardiff, Newport, Bristol, and Talgarth as part of our recent studies on British Slugs. The sequences were all but identical, supporting the theory that the species is not native to the UK. If you are going to report a sighting, please ensure that your slug is a true Ghost Slug (Selenochlamys ysbryda). This can be done by looking at the mantle and the eyes. The mantle (indicated by the grey lines) looks like a layer of skin through which the breathing hole is often visible. This Ghost Slug has a tiny, disc-shaped mantle at the rear end of its body. It has no eye spots on its tentacles (indicated by the arrow). Other white or pale slug species have a large, cloak-like mantle over their “shoulders” near the front of their body. They have black eye spots at the tips of two of their tentacles. The two shown here are the Netted Field Slug (Deroceras reticulatum) and Worm Slug (Boettgerilla pal lens). These species are very common in gardens, so there is no need to report them to us. The media The Ghost Slug was named one of the "Top 10 New Species of the Year" for 2009 by the US International Institute for Species Exploration. It has featured in exhibitions in Cardiff and Bristol, and even in school exam questions. It has also appeared in several books including Animal (Dorling Kindersley, 2011) and, most recently, in our own 2014 guide to the slug species of Britain and Ireland. Further sightings To monitor any spread or document behaviours we are still interested in future observations of Selenochlamys ysbryda, verified with a specimen or photograph. Please ensure that they are not the Netted Field Slug Deroceras reticulatum, shown above. To report a Ghost Slug, email Ben Rowson .
New species of fossil crinoid discovered in south Wales Cindy Howells, 3 February 2014 The discovery of any new type of fossil is one of the most exciting things that can happen to a palaeontologist. A new fossil discovered in south Wales – and the only one known of its kind - has been given the name Hylodecrinus cymrus to illustrate its Welsh origins. Whilst on a field trip to Pembrokeshire in 2009 to study the 350 million year old (Carboniferous Period) rocks in a small cove at West Angle Bay, Cindy Howells, a palaeontology curator at Amgueddfa Cymru, discovered an interesting new fossil that did not match any scientifically recorded specimen. In the Carboniferous Period Wales was located close to the equator and was covered with shallow tropical seas. The rocks here suggest there were many fierce tropical storms which usually smashed the shells of marine organisms into small pieces before they were fossilised. However a few layers contain whole fossils, deposited in quieter conditions, and in one of these the new specimen was found. Hylodecrinus cymrus – the holotype, and only specimen. Reconstruction of Hylodecrinus cymrus. The fossil is a crinoid, a small marine animal that looked a little like a plant. Crinoids have a long flexible stem, anchored into the sea-bed. This is topped with a small cup shaped structure containing its internal organs. Long flexible feathery tentacles, or arms, are extended up above the animal and these collect micro-organisms from the seawater and channel them down to its stomach. The new fossil was carefully extracted from the rocks and taken back to Cardiff. After consultation with Professor Tom Kammer from West Virginia University (an expert on Carboniferous crinoids), it was decided that this fossil was a new species and also belonged to a group never seen before outside the USA. It has been given the name Hylodecrinus cymrus to illustrate its Welsh origins. The description of this new fossil was published online in the Geological Journal. This specimen becomes the ‘type’ specimen of the species, against which others may be compared. As of 2013, it is the only known specimen of this species. The tropical seas of the Carboniferous Period were teeming with life including brachiopods, bivalves, gastropods, corals, fish and particularly crinoids. Rocks of this age are especially well exposed along the south Wales coastline, from Glamorgan to Pembrokeshire. Studies on fossils help us to understand how these rocks were deposited, and the conditions in which the animals preserved within them would have lived. Geological map of south Wales showing the location of West Angle Bay, Pembrokeshire
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.
Insects in Amber 25 July 2013 Please click on the thumbnails below to browse through a selection insects caught in amber. Amber insects Fungus gnat in amber 98.2G.2 Opilones Spider 98.7G.27 Moth 98.7G.24 Biting Midge and Moth 98.7G.1 Sciaindae Fungus Gnat
