̽��ֱ�� of Cambridge - paleontology

‘Treasure trove’ of dinosaur footprints found in southern England

sc604 — Mon, 17 Dec 2018 09:00:46 +0000

More than 85 well-preserved dinosaur footprints – made by at least seven different species – have been uncovered in East Sussex, representing the most diverse and detailed collection of these trace fossils from the Cretaceous Period found in the UK to date. Click here to find out more.

Neil Davies

Two large iguanodontian footprints with skin and claw impressions

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“A load of old rot”: fossil of oldest known land-dweller identified

sc604 — Wed, 02 Mar 2016 08:38:45 +0000

A fossil dating from 440 million years ago is not only the oldest example of a fossilised fungus, but is also the oldest fossil of any land-dwelling organism yet found. ̽��ֱ��organism, and others like it, played a key role in laying the groundwork for more complex plants, and later animals, to exist on land by kick-starting the process of rot and soil formation, which is vital to all life on land.

This early pioneer, known as Tortotubus, displays a structure similar to one found in some modern fungi, which likely enabled it to store and transport nutrients through the process of decomposition. Although it cannot be said to be the first organism to have lived on land, it is the oldest fossil of a terrestrial organism yet found. ̽��ֱ��results are published in the Botanical Journal of the Linnean Society.

“During the period when this organism existed, life was almost entirely restricted to the oceans: nothing more complex than simple mossy and lichen-like plants had yet evolved on the land,” said the paper’s author Dr Martin Smith, who conducted the work while at the ̽��ֱ�� of Cambridge’s Department of Earth Sciences, and is now based at Durham ̽��ֱ��. “But before there could be flowering plants or trees, or the animals that depend on them, the processes of rot and soil formation needed to be established.”

Working with a range of tiny microfossils from Sweden and Scotland, each shorter than a human hair is wide, Smith attempted to reconstruct the method of growth for two different types of fossils that were first identified in the 1980s. These fossils had once been thought to represent parts of two different organisms, but by identifying other fossils with ‘in-between’ forms, Smith was able to show that the fossils actually represented parts of a single organism at different stages of growth. By reconstructing how the organism grew, he was able to show that the fossils represent mycelium – the root-like filaments that fungi use to extract nutrients from soil.

It’s difficult to pinpoint exactly when life first migrated from the seas to the land, since useful features in the fossil record that could help identify the earliest land colonisers are rare, but it is generally agreed that the transition started early in the Palaeozoic era, between 500 and 450 million years ago. But before any complex forms of life could live on land, there needed to be nutrients there to support them. Fungi played a key role in the move to land, since by kick-starting the rotting process, a layer of fertile soil could eventually be built up, enabling plants with root systems to establish themselves, which in turn could support animal life.

Fungi play a vital role in the nitrogen cycle, in which nitrates in the soil are taken up by plant roots and passed along food chain into animals. Decomposing fungi convert nitrogen-containing compounds in plant and animal waste and remains back into nitrates, which are incorporated into the soil and can again be taken up by plants. These early fungi started the process by getting nitrogen and oxygen into the soil.

Smith found that Tortotubus had a cord-like structure, similar to that of some modern fungi, in which the main filament sends out primary and secondary branches that stick back onto the main filament, eventually enveloping it. This cord-like structure is often seen in land-based organisms, allowing them to spread out and colonise surfaces. In modern fungi, the structure is associated with the decomposition of matter, allowing a fungus colony to move nutrients to where they are needed – a useful adaptation in an environment where nutrients are scarce and unevenly distributed.

In contrast with early plants, which lacked roots and therefore had limited interaction with activity beneath the surface, fungi played an important role in stabilising sediment, encouraging weathering and forming soils.

“What we see in this fossil is complex fungal ‘behaviour’ in some of the earliest terrestrial ecosystems – contributing to soil formation and kick-starting the process of rotting on land,” said Smith. A question, however, is what was there for Tortotubus to decompose. According to Smith, it’s likely that there were bacteria or algae on land during this period, but these organisms are rarely found as fossils.

Additionally, the pattern of growth in Tortotubus echoes that of the mushroom-forming fungi, although unambiguous evidence of mushrooms has yet to be found in the Palaeozoic fossil record. “This fossil provides a hint that mushroom-forming fungi may have colonised the land before the first animals left the oceans,” said Smith. “It fills an important gap in the evolution of life on land.”

̽��ֱ��research was supported by Clare College, Cambridge.

Reference:
Martin R. Smith. ‘Cord-forming Palaeozoic fungi in terrestrial assemblages.’ Botanical Journal of the Linnean Society 180 (2016). DOI: 10.1111/boj.12389

̽��ֱ��earliest example of an organism living on land – an early type of fungus – has been identified. ̽��ֱ��organism, from 440 million years ago, likely kick-started the process of rot and soil formation, which encouraged the later growth and diversification of life on land.

Before there could be flowering plants or trees, or the animals that depend on them, the processes of rot and soil formation needed to be established.

Martin Smith

Martin R. Smith

Filaments of Tortotubus

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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Opinion: Six amazing dinosaur discoveries that changed the world

Anonymous — Mon, 30 Nov 2015 02:14:22 +0000

Recently, an auction of a dinosaur skeleton, discovered in Jurassic-aged rocks in the US, was held in West Sussex, England. ̽��ֱ��skeleton was that of a largely complete, immature, three-metre long carnivorous dinosaur: Allosaurus fragilis – “delicate strange reptile”. It was anticipated that the specimen would sell for somewhere in the region of £300,000-£500,000. Interestingly, bidding stopped before the reserve price was reached, so the specimen is still on the open market.

Allosaurus Scott Hartman, Author provided

̽��ֱ��price or value of fossils has a history that is practically as long as the science of palaeontology (the study of fossils) itself. Believe it or not, the tongue-twister “she sells seashells on the seashore” has its origin in the work of one of the earliest and most celebrated fossil collectors, Mary Anning. Mary lived during the early decades of the 19th century and had the knack of finding fossils, including those of seashells – bivalves, brachiopods, belemnites and ammonites – along the shores of Dorset and in the crumbling Jurassic cliffs, which she then sold.

Dinosaurs are fossils and do have a value, but I am only really interested in their value as scientific objects. Here are some of the discoveries that really have made a difference to science.

Megalosaurus

Pride of place must go to Megalosaurus bucklandi “Buckland’s big reptile” – because it proved to be the earliest discovered and scientifically described dinosaur.

Megalosaurus jaw Buckland Author provided

It’s remains, though incomplete, began to be collected from quarries at the village of Stonesfield in Oxfordshire in about 1815. ̽��ֱ��bones, teeth and jaws were passed to Oxford ̽��ֱ�� Museum, where they still reside, and were studied by the greatest living anatomist of the time Georges Cuvier, who visited Oxford (and its custodian William Buckland) from Paris to see the material.

William Buckland (with Cuvier’s help) described these fossils in a scientific article published in 1824. Buckland as well as Cuvier deduced that the bones belonged to a gigantic reptile, the like of which had not been seen before. Over the next decade and half more large fossil reptile bones were recovered in England and reviewed by the British anatomist Richard Owen. In 1842 Owen decided that these fossils were so utterly different from any known reptiles that they deserved to be classified as a completely new group of giant fossil reptiles: Dinosauria – “terrible, or fearfully great, reptiles”. Prior to 1842 nobody had heard of dinosaurs, the rest is, in essence, history. And Megalosaurus was the first.

Archaeopteryx

Charles Darwin profoundly disturbed the established Victorian world and galvanised scientific interest in evolution when he published his book On the Origin of Species in 1859. With masterly circumspection, his book laid out the reasons for concluding that organic life had changed or evolved over the immensity of geological time.

Archaeopteryx restored Robert Nicholls. Sedgwick Museum, ̽��ֱ�� of Cambridge

By an astonishing coincidence, a fossil was discovered in a quarry in southern Germany just one year after the publication of Origin. This fossil comprised the major part of the crow-sized, delicately-boned skeleton of a creature that was named by Richard Owen Archaeopteryx lithographica (“ancient wing on writing stone”).

̽��ֱ��fossil was extraordinary because around the bones were seen the impressions of feathers (which of course implied that this was a bird) yet what was also seen in the skeleton were clear traces of teeth (no bird has teeth), hands with three well-developed clawed fingers (no bird has clawed fingers of that type) and its tail comprised a long string of small bones from which radiated a fan of feathers (no bird has a long string of tail bones).

Archaeopteryx NHM Author provided

This animal was an absolutely perfect “missing link” that connected living birds with feathers, to the group of scaly reptiles with teeth in their jaws, clawed fingers and long bony tails. Just a few years after this discovery was announced a friend and colleague of Darwin’s, Thomas Henry Huxley, suggested on the basis of the structure of Archaeopteryx, that birds and dinosaurs (not just any old reptile) were close relatives.

Not many agreed with Huxley at the time, but he has been proved to have been absolutely correct. Its original remains are preserved at the Natural History Museum, London.

Diplodocus

Diplodocus Scott Hartman

Andrew Carnegie was a profoundly wealthy industrialist based in Pittsburgh, Pennsylvania during the latter half of the 19th century. After he had amassed his fortune, Carnegie began to spend his money philanthropically. News came to him of the discovery of impressive dinosaur skeletons in the American mid-west so he decided he wanted one for his new museum ( ̽��ֱ��Carnegie Museum) in Pittsburgh. So he financed expeditions to northern Wyoming and southern Utah to find some more dinosaurs. And find them they did, including a near complete skeleton of the biggest dinosaur discovered to date.

̽��ֱ��skeleton was named Diplodocus carnegiei – "Carnegie’s double-beam". ̽��ֱ��entire animal, as reconstructed (with just a few additions for completeness, such as “borrowed” front feet from another animal altogether) was over 25 metres long and dwarfed in size and completeness anything discovered up to that date.

Diplodocus at the Natural History Museum Valdiney Pimenta/flickr, CC BY

So proud of this dinosaur was Carnegie that he had many copies cast in plaster and sent to museums around the world. ̽��ֱ��giant dinosaur in the main hall of the Natural History Museum in London is a cast of Carnegie’s Diplodocus.

Deinonychus

In the mid 1960s a young palaeontology professor, John Ostrom from Yale ̽��ֱ�� was exploring the badlands of Montana looking for dinosaur fossils. What he found was to change our understanding of dinosaurs, their biology and behaviour in the most extraordinary way. Ostrom discovered the scattered remains of a medium-sized predatory dinosaur which he studied and then named Deinonychus antirrhopus – “Terrible claw with a counterbalance”.

Deinonychus Scott Hartman, Author provided

He realised that this animal was a fast moving, highly intelligent, keen-sighted predator (not at all the slow, lumbering and slow-witted image of the dinosaur that was current at the time). He also showed that it was remarkably bird-like in its anatomy, and suggested that the bird similarities suggested that birds and small predatory dinosaurs were so closely similar that birds probably evolved from them.

These were highly controversial views at the time, even though they echoed the early ideas of Thomas Huxley in the 1860s. They also posed serious biological questions: if birds and dinosaurs of this type are related could it be that some dinosaurs were more like birds in a biological sense? ̽��ֱ��debate raged for decades.

Scelidosaurus

I include this dinosaur, which is somewhat less heralded than the others, because it really ought to have been a dinosaur that changed the world.

Scelidosaurus Gregory S Paul, Author provided

In 1858 dinosaur bones were discovered in the Jurassic cliffs at Charmouth and soon a nearly complete skeleton of this dinosaur was excavated and given to Richard Owen (the person who invented the Dinosauria) at the British Museum in London.

In the 1860s, Owen named it Scelidosaurus harrisonii – "Harrison’s shoulder reptile", but almost inexplicably failed to grasp the importance of its anatomy, or the way in which it pointed to the divisions between differing dinosaur groups and, in fact, why dinosaurs had proved so difficult to understand at the time.

Owen had the equivalent of a Rosetta Stone before him, yet he failed to grasp its importance. ̽��ֱ��probable reason why such an insightful scientist missed such an important moment is that he was simply too busy, including setting in motion the plans to have an entirely new national museum built. Without Owen the Natural History Museum in London, where the original bones of Scelidosaurus still lie, would not have been constructed. In fact, I am studying them at this very moment – hence my undoubted bias.

Sinosauropteryx

In 1996 an astonishing discovery was made in Liaoning, China. It comprised a virtually complete skeleton of a small, predatory dinosaur (smaller than, but generally similar to, Deinonychus).

Sinosauropteryx Author provided

It was described briefly in 1998 and named Sinosauropteryx prima – “First Chinese reptile wing” – but the most extraordinary feature associated with this fossil was that on the rocky slab upon which the skeleton was displayed there were traces of a wispy, dark-staining material that formed a sort of fringe following the body outline, as well as forming a dark spot in the area of the eye, and also formed a dark mass in the area of the gut/body cavity. ̽��ֱ��conditions of exceptional fossil preservation associated with these rocks in Liaoning seemed to preserve some remnant of the body tissues of the original animal.

Most intriguing was the fringe of tissue around the body: it looked like fur. ̽��ֱ��implication was that it had an epidermal covering (outer coat), perhaps an insulating layer. Given Ostrom’s earlier work on Deinonychus, the suggestion was made that this was indeed an insulated dinosaur that was able to keep its body warm (rather like a modern bird using fine down-like feathers that might have been preserved as a halo-like fringe when fossilised).

Still with us? Danny Chapman/flickr, CC BY

This and subsequent discoveries demonstrated the wisdom of Huxley’s intuition based largely upon Archaeopteryx and the validity of Ostrom’s work on Deinonychus. We now know that many (but not all) dinosaurs were feathered, and that some were capable of flight and some were indeed the progenitors of modern birds.

David Norman, Reader in Paleobiology, Curator of Palaeontology, Sedgwick Museum of Earth Sciences, ̽��ֱ�� of Cambridge

This article was originally published on ̽��ֱ��Conversation. Read the original article.

̽��ֱ��opinions expressed in this article are those of the individual author(s) and do not represent the views of the ̽��ֱ�� of Cambridge.

David Norman (Sedgwick Museum of Earth Sciences) discusses the fossil discoveries that really made a difference to science.

David Nicholls. Sedgwick Museum, ̽��ֱ�� of Cambridge

Deinonychus

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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