Wealden insects: An artist’s update (Part 4)

Biddy and Ed Jarzembowski (UK) An ‘artist’s impression’ of Wealden insects, inspired by the original work of Neil Watson, appeared in a three-part mini-series in Deposits issues 47 to 49. Since then, the discovery of a number of species new to science (belonging to diverse groups) has meant that an update was needed. Here are some completely new watercolours by Biddy, including the first true bug (heteropteran) from the Wealden, and the first Wealden earwig (dermapteran). Insects are arthropods and an accompanying Wealden crustacean is added this time. Photographs of actual fossils found in the Weald Clay Formation of Lower Cretaceous (Hauterivian and Barremian) age are provided too. We are indebted to Fred Clouter, Terry Keenan, Tony Mitchell and Pete Austen (UK) for help with these images. As before, Ed has supplied some explanatory notes to accompany the pictures, with more on the way. We have incorporated some new ideas on established species, such as different interpretations of the fossil lifestyle in the case of the ‘moss’ bug. Wealden insects are often disarticulated (due to transport in water). Where intact relatives are known from other contemporary deposits (especially Asia and Spain), these have been referred to, as well as recent representatives. While we can now recognise the commoner insect groups from the late age of the dinosaurs, continuing fieldwork shows that others remain to be unearthed. The artist’s job is ongoing, like that of the specialist and collector. We shall continue to periodically share the finds with you as a … Read More

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Hans Sloane’s fossil collection at the Natural History Museum, London

Dr Consuelo Sendino (UK) Sir Hans Sloane, the Founder of the British Museum, accumulated a large number of fossilised remains of animals and plants throughout his life. His collection, including curiosities from all around the known world, was acquired by the British Government in 1753 as part of Sloane’s bequest to the nation. It formed the core of the fossil collection of the Department of Natural History in the British Museum, and is now conserved in the Department of Earth Sciences at the Natural History Museum in London. Fig. 1. The statue of Sir Hans Sloane at Chelsea Physic Garden, London. This was unveiled on 30 April 2014 by a descendant of Sloane, Earl Cadogan. Hans Sloane (16 April 1660 – 11 January 1753) Hans Sloane was born on 16 April 1660 at 49 Frederick Street in Killyleagh, County Down in Ireland, although he was of Scottish ancestry. From a young age, Sloane showed an inclination for the study of natural history and medicine, collecting specimens from nearby Strangford Lough and as far afield as the Copeland Islands. He began studying medicine in 1679 in London, and finished his training in Paris and Montpellier in France, receiving his doctor of medicine degree at the University of Orange in France, on 28 July 1683. During this time, he was a frequent visitor to the Chelsea Physic Garden, established in 1673 by the Company of Apothecaries, as botany was considered to be fundamental to the medical curriculum. On his return to London, … Read More

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Fossil crustaceans as parasites and hosts

Adiël Klompmaker (USA) Who would like to carry a parasite? I bet not many people would like to have one or more. They are nevertheless very common in humans and in other organisms, and can affect entire food webs including keystone species. They tend to be small compared to the host and the vast majority of them are soft-bodied. Despite their small size and soft appearance, they can affect the host substantially, for example, leading to a reduced growth rate and less offspring. Much of the same holds true for crustaceans – they are affected by parasites and can act as parasites themselves. For example, parasitic crustaceans are found among the isopods and copepods. Given the widespread occurrence of parasitism in and by crustaceans today, a fossil record of such parasitism may be expected. Swellings in fossil crabs and squat lobsters So what does the fossil record look like? I have been fortunate to have worked on this under-studied field of research. During my PhD research, I found various swellings in fossil crabs and squat lobsters (decapods from the superfamily Galatheoidea) during and after field work in northern Spain in reef carbonates from the mid-Cretaceous (upper Albian). They appeared to occur regularly in the back part of the carapaces of these crustaceans. Fig. 1. Bopyrid isopods from the species Orthione griffenis (large female and small male), removed from the right gill chamber of a modern mud shrimp (Upogebia pugettensis). (Photo by Stephen Ausmus, USDA Agricultural Research Service, http://www.bugwood.org.) This swelling … Read More

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Other mass extinctions

Neal Monks (UK) The extinctions at the Cretaceous-Tertiary (K/T) boundary make up what is probably the most famous geological event in popular culture. This is the point when the great reptiles that characterise the Mesozoic went extinct. Alongside the dinosaurs, the giant marine reptiles died out too, as did the pterosaurs, and a whole host of marine invertebrates, including the ammonites and belemnites. What happened? Some geologists argue the climate changed over a period of a million years or more, thanks to the massive volcanism that created the Deccan Traps in India. Others maintain that the K/T extinctions happened suddenly, pointing to evidence of a collision between the Earth and an asteroid. Perhaps there wasn’t a single cause, but rather a variety of factors: volcanism, climate change, asteroid impact, underlying changes in flora and fauna, and perhaps even variation in the output of the Sun and resulting weather patterns. That life on Earth can be wiped out this way is the stuff of disaster movies as much as TV documentaries. However, what comes as a surprise to many people is that there wasn’t just one mass extinction at the K/T boundary, but a whole series of them that can be observed throughout the fossil record. One of them, the Permo-Triassic extinctions, appear to have been even more catastrophic than the K/T extinctions, and at least three other extinction events are comparable in scale. In between these five big extinctions were lots of smaller extinctions that aren’t well studied, but had … Read More

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Harvesting the extinct Bennettitales

Stephen McLoughlin and Christian Pott (Sweden) Just as the animal kingdom lost some remarkable designs during the mass extinction events that punctuated the Palaeozoic and Mesozoic (consider the disappearance of the novel carapaces of trilobites and the aerofoils of pterosaurs), so too the plant kingdom lost some majestic groups that, had they survived until today, would no doubt have been cultivated as centrepieces in many domestic gardens. One such group is the Bennettitales. The Bennettitales were enigmatic, seed-bearing plants (gymnosperms) characterised by complex reproductive structures, some of which are not yet fully understood. Bennettitales are historically divided into two families, the Cycadeoidaceae (or Bennettitaceae) and the Williamsoniaceae. The two families are distinguished primarily by their growth habit and the arrangement of their reproductive organs. The former have short, stocky trunks somewhat like modern cycads, whereas the latter had slender, profusely branched stems. The former appear to have been restricted to the Jurassic-Cretaceous of western Laurasia, whereas the latter had a global distribution and greater temporal range. They were neither the smallest plants of the Mesozoic nor the largest. They were one of the important, mid-storey elements of the vegetation. If you care to view almost any artist’s reconstruction of a Jurassic landscape you will no doubt see bennettitaleans growing around the feet of (or being eaten by) a large sauropod or ornithischian dinosaur. Fig. 1.. A 45cm-tall permineralized cycadeoidaceae stem (Cycadeoidea dacotensis) from the Cretaceous of northern USA. Flowers before there were flowers Apart from their growth habit, the most … Read More

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Tertiary cephalopods, or where did all the ammonites go?

Dr Neale Monks (UK) Most geologists will be familiar with Palaeozoic and Mesozoic cephalopods, but their Tertiary counterparts are much less well known. It isn’t that Tertiary cephalopods are rare as such – at some localities they can be quite common – but their diversity is extremely low. For example, the Gault Clay is a Lower Cretaceous formation that has yielded hundreds of cephalopods species, including ammonites, belemnites and nautiloids. Fast-forward to the London Clay, an Eocene formation, and that diversity falls to about five species, at most. At first glance, you would think this reflects the fatal decline of a group marching towards extinction. However, there are 700 cephalopod species alive today, so clearly that isn’t the case. In fact, what the lack of Tertiary cephalopod fossils shows is the switch within the group from forms with shells (such as ammonites and nautiluses) towards forms that don’t have shells (like squids and octopuses). Because they don’t have hard parts that fossilise easily, squids and octopuses have an extremely sparse fossil record. Nonetheless, the Tertiary isn’t entirely devoid of cephalopods if you know where to look. The London Clay exposure at Sheppey is a particularly good place to find nautiloid fossils. Occasional specimens from other cephalopod groups occasionally turn up as well and these give us some fascinating glimpses into the evolution of the post-Cretaceous cephalopods. Fig. 1. Warden Point, on the Isle of Sheppey, is one of the best places to collect Tertiary cephalopods (UKGE photo). Nautiloids Perhaps surprisingly, the … Read More

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Fossil forests in the freezer

Stephen McLoughlin (Sweden) South of the craggy limits of Patagonia, Africa and Tasmania, and beyond the piercing gales of the roaring forties and the furious fifties, lies Antarctica – the last great continent on Earth to be explored. Straddling the South Pole, it lies frozen in a winter that has lasted millions of years. Today, only a few plant species more robust than mosses eke out a harsh existence on its warmest fringes. The bitter cold and screaming katabatic winds (a katabatic wind is one that carries high density air down a slope under the force of gravity) that drain off the continental interior mean that few plants and animals can survive in Antarctica year-round. However, this has not always been the case. Through much of deep time, it has not been the ‘white continent’ but a land of green forests and lush swamps. This forested landscape provided habitats for a wide range of terrestrial animals for most of the past 400 million years. The continent’s central location within the ancient southern supercontinent of Gondwana also meant that it held an important role in the exchange of plants and animals between the southern lands. Fig. 1. Map of Antarctica showing the Permian-Triassic basins. Early clues Little was known about Antarctica’s geology or fossil heritage until ‘the heroic era of exploration’ began to unlock the continent’s secrets in the 1800s. Some of the first explorers to realize that vegetation once clothed Antarctica’s landscape were the members of Captain Robert Scott’s team, … Read More

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