Rudists: A fossil story

Jack Shimon (USA) This article is adapted from a presentation given at the Denver Gem Show, September 17, 2016 by me, Jack Shimon. When I was six and a half years old, my Grandpa took me fossil hunting in central Texas. We went to a Carboniferous Limestone quarry that he had visited earlier and was given permission to enter and collect from. This was one of my first fossil hunting trips and I really enjoyed it. The ancient reef we went to (now a quarry) had huge boulders of limestone and tube-like things in it we later to be found to be rudist bivalves. This article is all about these finds and the efforts we went to, to find out what they were. Fig 1. The author at the quarry. (Photo credit: Mike Hursey.) Fig. 2. This Google satellite image shows the reef we collected from. Two of the three lobes have been excavated for limestone. You can also see smaller pinnacle reefs marked with the short arrows. All of the reefs rise above the flat Texas landscape. (Permission from Google.com: ‘Special Use Guidelines’.) Fossils We spent a lot of time at the quarry observing the massive specimens onsite and then collected some smaller pieces to bring home and look at closer. A simple way of thinking about fossils is to consider them either as a cast or a mould. A mould is formed when an object is placed into a soft substrate and then decomposes or is washed away … Read More

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Prominent figures of the 1800s who gave rise to vertebrate palaeontology

Megan Jacobs (UK) For centuries, the creatures of the past, from the terrifying theropod dinosaurs to the tiny early mammals, have captured the imaginations of millions. However, the people who put those beasts into the limelight are rarely acknowledged for their work and, in many cases, remain unknown. So here is a short account of some of the first prominent names in the world of vertebrate palaeontology, their contributions to the field, and an insight into the often eccentric behaviour that came with it. Georges Cuvier (1769-1832) Fig. 1. Georges Cuvier.Georges Cuvier was a French naturalist and zoologist, and is regarded as the ‘’father of palaeontology’’. He was one of the finest minds in history, founding vertebrate palaeontology as a scientific discipline. For example, in 1800, he identified Pterodactylus as the first known pterosaur from a print published by Alessandro Collini. Shortly after, he described the first mosasaur, a giant marine reptile that was brought to France by Napoleon after he conquered the Netherlands. Going against his old Christian (Catholic) upbringing, Cuvier believed the Earth was immensely old and, during its history, underwent abrupt changes that Cuvier called ‘revolutions’, in which large numbers of species were wiped out. This was the first recognition that extinctions were facts. Cuvier also rightly speculated that there had been a time where reptiles had been the dominant animals on the planet. Indeed, the decades after his death yielded spectacular finds that confirmed his theory. After a study comparing modern elephant species, he worked on … Read More

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Triassic beasts and where to find them

Sue Beardmore (UK) Located amid the scenic Southern Alps, on the Swiss-Italian border, is Monte San Giorgio, a mountain that rose up like many across Central Europe as a result of continental collision between Africa and Europe during the Alpine Orogeny. It is not particularly big or distinct by alpine standards but it is special, a status emphasised by the designation of its slopes as a UNESCO World Heritage site initially in 2003 for the Swiss part with the neighbouring Italian area added in 2010. To begin, the rocks outcropping on the mountain form an almost complete stratigraphic sequence from the Permian through to the Jurassic (Fig. 1), not only an extended interval of time but an important one around the massive Permo-Triassic extinction. The same rocks provide a context for the equally important Middle Triassic vertebrate, invertebrate and plant fossils, now numbering more than 20,000, that have been found at the locality over the last 170 years. Fig. 1. A stratigraphic section of the rocks at Monte San Giorgio. © Commissione Scientifica Transnazionale Monte San Giorgio, 2014. In particular, it is the diversity, relative abundance and excellent preservation of the vertebrate fossils that has thrown the locality into the spotlight. These occur in six main fossiliferous horizons deposited in a shallow marine basin, the Monte San Giorgio Basin, one of many depressions on a carbonate platform between the Eurasian continent to the north and west, and the open waters of the vast Tethys Ocean to the south and east. … Read More

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Fossil folklore: Molluscs

Paul D Taylor (UK) The final article of this series on fossil folklore focuses on molluscs, excluding the ammonites, which were covered earlier (see Fossil folklore: ammonites in Deposits, Issue 46, pp. 20–23). Molluscs are second only to arthropods in the number of species living today and the resistant calcareous skeletons possessed by the majority of species accounts for their extremely rich fossil record. Most fossil molluscs belong to one of three major groups – bivalves (oysters, clams and so on), gastropods (snails and slugs) and cephalopods (ammonites, belemnites and so on). Added to these are a few minor groups, such as the monoplacophorans and scaphopods (tusk shells). Fossil molluscs are usually recognisable instantly as belonging to this phylum because of their close similarities with the shells of familiar species of modern molluscs. Some, however, are not quite so straightforward. These are more likely to have been the sources of fanciful stories about their origins and significance. Among the more obscure ancient molluscs are those dubbed ‘difficult fossils’ by Martin Rudwick in the context of the early history of palaeontology and doubts over the origin of fossils. They include the solid internal casts (steinkerns) formed by lithification of sediment enclosed by the shell and subsequent loss of the defining shell itself. In addition, there are some mollusc fossils – notably belemnite guards – that bear little resemblance to any living species, adding to their enigmatic nature. Belemnites: thunderbolts and Devil’s Fingers The first fossils I ever came across were belemnites … Read More

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Tully Monster: Is this the world’s most mysterious fossil?

James O’Donoghue (UK) The Tully Monster is a mysterious 307Ma-old marine animal known only from the famous Mazon Creek fossil locality in Illinois. Its body plan is unlike any other animal that has ever lived, and it has been subject to wildly different interpretations as to its identity since its discovery in 1955. Last year, Victoria McCoy of Yale University and colleagues identified it as a lamprey, a primitive type of fish, but this has since been challenged by a team of vertebrate palaeontologists. Fig. 1. Reconstruction of a Tully monster based on the research of McCoy and colleagues. The claw and proboscis are on the right and its eyebar and eyes, gills and tail fin are further back. (Sean McMahon/Yale University.) Fossil collector Francis Tully knew he had made an extraordinary discovery. Inside a rounded nodule was a bizarre, foot-long animal with a long trunk and claw. But he could never have known quite how extraordinary his 307Ma-old fossil would turn out to be. Sixty two years later, scientists are still arguing over the basics as to what sort of creature it really was. What makes it even stranger is that this is no rarity known only from fragmentary remains. After Tully made his find, word got around among collectors and, before long, hundreds more had been found. Tullimonstrum gregarium, or ‘Tully’s common monster’, is now known from well over a thousand fossils, including many complete specimens. “We’ve got four cabinets of Tully monsters here, each of which has … Read More

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Urban geology: A rostroconch in Hoofddorp

Stephen K Donovan (The Netherlands) Part of my job is to provide service teaching for the University of Leiden. The university lacks a geology department, but my colleagues and I provide tuition in stratigraphy and palaeontology for life science students at the undergraduate and masters degree level. One of my favourite practical classes is a building stones tour of a part of Leiden that is rich in Mississippian (Lower Carboniferous) limestones, which are packed with fossils. These have been used for facing stones, external stairs and paving slabs. Many have been in place for some hundreds of years and many have been etched by slow solution by rainwater as a result. Common fossils include crinoid columnals, tabulate and rugose corals, brachiopods, and molluscs (Donovan, 2016; van Ruiten and Donovan, in review). These are most commonly seen in two dimensions and random sections, a different view of life to what the life scientists are usually accustomed. One group of fossils in these rocks were a mystery until recently, but we now know they are sections through rostroconchs (Donovan and Madern, 2016, p. 349), an extinct group of Palaeozoic molluscs. Rostroconchs were formerly considered to be an ancient group of bivalves and they are certainly bivalve-like in appearance, but lack an articulation of interlocking teeth and a ligament. That is, the shell is a univalve, a one-piece structure. I had only seen the sections of rostroconchs in building stones in Leiden. It was therefore gratifying, shortly after publication of these fossils, to … Read More

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All change at Selsey, West Sussex, UK

David Bone (UK) Issue 26 of Deposits magazine in the Spring of 2011 included my article on fossil collecting at Bracklesham Bay in West Sussex, following in the footsteps of my guide book on Fossil hunting at Bracklesham & Selsey, published in 2009. This area has been well known for the foreshore exposures of Palaeogene and Quaternary geology since the mid-nineteenth century and is still very much an area for popular fossil collecting, as well as research. Many readers will have been to Bracklesham or Selsey to collect sharks’ teeth and may have even been lucky enough to find a piece of mammoth bone or tooth. The scientific value of the area is recognised by much of the coastline being designated as a geological Site of Special Scientific Interest (or SSSI). However, this has been impacted by two major coastal defence schemes at Selsey that were completed in 2013, significantly changing access to the foreshore and any exposures of the geology, as well as rendering my guide book in need of a major update. In medieval times, Selsey was effectively an island, although this is no longer the case due to the construction of sea defences and land reclamation. However, Selsey remains a localised area of higher land surrounded by low-lying land prone to flooding (Fig. 1). It has also been an area of coastal erosion and loss of land to the sea throughout recorded history. The relatively unconsolidated Palaeogene and Quaternary sediments exposed in the low cliffs of the … Read More

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Invertebrate fossils from the Lower Muschelkalk (Triassic, Anisian) of Winterswijk, The Netherlands

Henk Oosterink (The Netherlands) During the Muschelkalk part of the Ansian (240mya), the Central European area (Germany, Poland, Denmark, The Netherlands and north-eastern France) was covered by a shallow sea, referred to as the Muschelkalk Sea. While there were frequent regressions and transgressions (leading to both marine and terrestrial fossil being present in these regions), it is from this sea that the limestones from this quarry were deposited and in which most of the fossilised animals discussed in this article lived. The quarry in the Muschelkalk at Winterswijk, in the east of the Netherlands (Fig. 1), is especially well known for the skeletons, bones, footprints and tracks of Middle Triassic reptiles. I wrote about these in Issues 15 and 20 of Deposits. However, fossils of invertebrates, such as molluscs, brachiopods and arthropods can also be found. Included in the molluscs are bivalves, cephalopods and gastropods, and from the brachiopods, the Inarticulata are present. From the arthropods, there are Malacostraca, Merostomata and insects. Fig. 1. Lower Muschelkalk quarry near Winterswijk (Eastern Netherlands). Mollusca Bivalves Some strata contain a large number of moulds of bivalves. These are situated quite high in the profile and, if you find this level, it is important to split the rock along an irregular dark-grey line (Fig. 2). If you do this, you will find the moulds of the convex upper side of the separated shells on one slab, with the negative impression visible on the other. This makes clear that these are valves swept together by … Read More

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Mollusc diversity for palaeontologists

Dr Neale Monks (UK) While arthropods and roundworms exceed the phylum Mollusca in terms of species, molluscs hold their own when it comes to anatomical diversity. There may be well over a million species of arthropod, but crabs, spiders and bees are all obviously related, sharing the same multi-limbed body plan organised around a jointed exoskeleton. Molluscs are very different. Clams, snails and squid are all molluscs, but their anatomy, ecology and behaviour couldn’t be more different. What molluscs have in common Although incredibly diverse, molluscs do have features in common. These include: A fleshy foot used for locomotion.A visceral mass containing the internal organs.A mantle that secretes the shell.A toothy tongue, known as a radula, for scraping food into smaller pieces.A shell made from calcium carbonate.Not all molluscs have all of these features, but they each have at least some of them. So, while an octopus doesn’t have a shell, it does have a mantle and a radula, as well as a foot divided up into the eight arms that give it its name. From the perspective of the palaeontologist, the key thing about molluscs is that most have (or had) shells. These fossilise more readily than soft tissues or even bones, and that means that molluscs have a remarkably rich fossil record. Origins The earliest fossil molluscs are known from the very base of the Cambrian, the Tommotian, about 530mya. This period of time was marked by the appearance of several major animal groups alongside molluscs, including arthropods, … Read More

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