The Great London [by United Kingdom] 

The diversity of mammals on Earth exploded straight after the dinosaur extinction event, according to UCL researchers. New analysis of the fossil record shows that placental mammals, the group that today includes nearly 5000 species including humans, became more varied in anatomy during the Paleocene epoch - the 10 million years immediately following the event.

Senior author, Dr Anjali Goswami (UCL Genetics, Evolution & Environment), said: "When dinosaurs went extinct, a lot of competitors and predators of mammals disappeared, meaning that a great deal of the pressure limiting what mammals could do ecologically was removed. They clearly took advantage of that opportunity, as we can see by their rapid increases in body size and ecological diversity. Mammals evolved a greater variety of forms in the first few million years after the dinosaurs went extinct than in the previous 160 million years of mammal evolution under the rule of dinosaurs."

The Natural Environment Research Council-funded research, published today in the Biological Journal of the Linnean Society, studied the early evolution of placental mammals, the group including elephants, sloths, cats, dolphins and humans. The scientists gained a deeper understanding of how the diversity of the mammals that roamed the Earth before and after the dinosaur extinction changed as a result of that event.

Placental mammal fossils from this period have been previously overlooked as they were hard to place in the mammal tree of life because they lack many features that help to classify the living groups of placental mammals. Through recent work by the same team at UCL, this issue was resolved by creating a new tree of life for placental mammals, including these early forms, which was described in a study published in Biological Reviews yesterday.

First author of both papers, Dr Thomas Halliday (UCL Earth Sciences and Genetics, Evolution & Environment), said: "The mass extinction that wiped out the dinosaurs 66 million years ago is traditionally acknowledged as the start of the 'Age of Mammals' because several types of mammal appear for the first time immediately afterwards.

"Many recent studies suggest that little changed in mammal evolution during the Paleocene but these analyses don't include fossils from that time. When we look at the mammals that were present, we find a burst of evolution into new forms, followed by specialisation that finally resulted in the groups of mammals we see today. The earliest placental mammal fossils appear only a few hundred thousand years after the mass extinction, suggesting the event played a key role in diversification of the mammal group to which we belong."

The team studied the bones and teeth of 904 placental fossils to measure the anatomical differences between species. This information was used to build an updated tree of life containing 177 species within Eutheria (the group of mammals including all species more closely related to us than to kangaroos) including 94 from the Paleocene - making it the tree with the largest representation from Paleocene mammals to date. The new tree was analysed in time sections from 140 million years ago to present day, revealing the change in the variety of species.

Three different methods were used by the team to investigate the range and variation of the mammals present and all showed an explosion in mammal diversity after the dinosaur extinction. This is consistent with theories that mammals flourished when dinosaurs were no longer hunting them or competing with them for resources.

Dr Anjali Goswami (UCL Genetics, Evolution & Environment), added: "Extinctions are obviously terrible for the groups that go extinct, non-avian dinosaurs in this case, but they can create great opportunities for the species that survive, such as placental mammals, and the descendants of dinosaurs: birds."

Professor Paul Upchurch (UCL Earth Sciences), co-author of the Biological Reviews study, added: "Several previous methodological studies have shown that it is important to include as many species in an evolutionary tree as possible: this generally improves the accuracy of the tree. By producing such a large data set, we hope that our evolutionary tree for Paleocene mammals is more robust and reliable than any of the previous ones. Moreover, such large trees are very useful for future studies of large-scale evolutionary patterns, such as how early placental mammals dispersed across the continents via land bridges that no longer exist today."

The team are now investigating rates of evolution in these mammals, as well as looking at body size more specifically. Further work will involve building data from DNA into these analyses, to extend these studies to modern mammals.

Source: University College London [December 21, 2015]

A painting hanging on the wall in an art gallery tells one story. What lies beneath its surface may tell quite another.

Often in a Rembrandt, a Vermeer, a Leonardo, a Van Eyck, or any other great masterpiece of western art, the layers of paint are covered with varnish, sometimes several coats applied at different times over their history. The varnish was originally applied to protect the paint underneath and make the colors appear more vivid, but over the centuries it can degrade. Conservators carefully clean off the old varnish and replace it with new, but to do this safely it is useful to understand the materials and structure of the painting beneath the surface. Conservation scientists can glean this information by analyzing the hidden layers of paint and varnish.

Now, researchers from Nottingham Trent University's School of Science and Technology have partnered with the National Gallery in London to develop an instrument capable of non-invasively capturing subsurface details from artwork at a high resolution. Their setup, published in an Optics Express paper, will allow conservators and conservation scientists to more effectively peek beneath the surface of paintings and artifacts to learn not only how the artist built up the original composition, but also what coatings have been applied to it over the years.

Traditionally, analyzing the layers of a painting requires taking a very small physical sample -- usually around a quarter of a millimeter across -- to view under a microscope. The technique provides a cross-section of the painting's layers, which can be imaged at high resolution and analyzed to gain detailed information on the chemical composition of the paint, but does involve removing some original paint, even if only a very tiny amount. When studying valuable masterpieces, conservation scientists must therefore sample very selectively from already-damaged areas, often only taking a few minute samples from a large canvas.

More recently, researchers have begun to use non-invasive imaging techniques to study paintings and other historical artifacts. For example, Optical Coherence Tomography (OCT) was originally developed for medical imaging but has also been applied to art conservation. Because it uses a beam of light to scan the intact painting without removing physical samples, OCT allows researchers to analyze the painting more extensively. However, the spatial resolution of commercially-available OCT setups is not high enough to fully map the fine layers of paint and varnish.

The Nottingham Trent University researchers gave OCT an upgrade. "We're trying to see how far we can go with non-invasive techniques. We wanted to reach the kind of resolution that conventional destructive techniques have reached," explained Haida Liang, who led the project.

In OCT, a beam of light is split: half is directed towards the sample, and the other half is sent to a reference mirror. The light scatters off both of these surfaces. By measuring the combined signal, which effectively compares the returned light from the sample versus the reference, the apparatus can determine how far into the sample the light penetrated. By repeating this procedure many times across an area, researchers can build up a cross-sectional map of the painting.

Liang and her colleagues used a broadband laser-like light source -- a concentrated beam of light containing a wide range of frequencies. The wider frequency range allows for more precise data collection, but such light sources were not commercially available until recently.

Along with a few other modifications, the addition of the broadband light source enabled the apparatus to scan the painting at a higher resolution. When tested on a late 16th-century copy of a Raphael painting, housed at the National Gallery in London, it performed as well as traditional invasive imaging techniques.

"We are able to not only match the resolution but also to see some of the layer structures with better contrast. That's because OCT is particularly sensitive to changes in refractive index," said Liang. In some places, the ultra-high resolution OCT setup identified varnish layers that were almost indistinguishable from each other under the microscope.

Eventually, the researchers plan to make their instrument available to other art institutions. It could also be useful for analyzing historical manuscripts, which cannot be physically sampled in the same way that paintings can.

In a parallel paper recently published in Optics Express, the researchers also improved the depth into the painting that their apparatus can scan. The two goals are somewhat at odds: using a longer wavelength light source could enhance the penetration depth, but shorter wavelength light (as used in their current setup) provides the best resolution.

"The next challenge is perhaps to be able to do that in one instrument, as well as to extract chemical information from different layers," said Liang.

Source: The Optical Society [April 13, 2015]

London's relentless building boom has dug up another chunk of the city's history — one with a surprise for scholars of Shakespearean theatre.

Archaeologists are excavating the remains of the Curtain, a 16th-century playhouse where some of the Bard's plays were first staged, before a new apartment tower sprouts on the site. Unexpectedly, the dig has revealed that the venue wasn't round, like most Elizabethan playhouses. It was rectangular.

That came as a surprise, because the best-known fact about the Curtain is that Shakespeare's "Henry V" was first staged here — and the play's prologue refers to the building as "this wooden O."

"This is palpably not a circle," Julian Bowsher, an expert on Elizabethan theatres, said during a tour of the site Tuesday.

The discovery has made Bowsher rethink some of his ideas about Tudor playhouses. He suspects that the Curtain — unlike the more famous Globe and Rose theatres — wasn't built from scratch, but converted from an existing building.

"Out of the nine playhouses that we know in Tudor London, there are only two that have no reference to any construction," he said — including the Curtain. "It's beginning to make sense now."

Where does that leave "Henry V"? Heather Knight, senior archaeologist at Museum of London Archaeology , said the play may still have premiered at the Curtain in 1599, but without the prologue.

"There's a school of thought now that says prologues were actually a later addition," she said.

The Curtain's remains were uncovered in 2011 on a site earmarked for development in Shoreditch, a scruffy-chic, fast-gentrifying area on the edge of London's financial district.

Archaeologists began excavating intensively last month, before construction of a 37-storey luxury apartment tower and office complex named — with a nod to its heritage — The Stage.

They will keep digging until the end of June, and visitors can book tours of the excavations as part of events to mark this year's 400th anniversary of Shakespeare's death.

The site's developers have promised to keep the foundations of the historic theatre on public view and to build a visitor center to display some of the archaeologists' finds.

These include clay pipes that were used to smoke tobacco — introduced to Britain from North America in the 16th century — and a bird whistle which may have been used as a theatrical special effect. It could have featured in the scene in "Romeo and Juliet" — performed at the Curtain — in which the heroine reassures her lover that "it was the nightingale, and not the lark" that he'd heard.

Knight says the Curtain site "has probably the best preserved remains of any of the playhouses we've looked at."

The dig has uncovered the outline of a rectangular venue about 100 feet (30 metres) by 72 feet (22 metres) that could hold about 1,000 people. Workers have uncovered sections of the theatre's gravel yard, where "groundlings" who had bought cheap tickets stood, and segments of wall up to 5 feet (1.5 metres) high.

The new building that will rise on the site — where apartments are being offered starting at 695,000 pounds ($1 million) — is part of a construction boom, fueled by London's sky-high property prices, that is transforming large tracts of the city. In the process, it is creating something of a golden era for London archaeology.

Nearby, work on the new Crossrail transit line has uncovered everything from 14th-century plague victims to Roman sandals.

Knight says the Curtain dig is filling in the picture of one of the oldest and least-known London playhouses, which served as a base for Shakespeare's troupe, the Lord Chamberlain's Men, between 1597 and 1599.

"This will give us real insight into these early playing spaces," Knight said. "It will help us understand the type of building that playwrights were writing for as well as performing in.

"It will also help us understand what type of audience was attending performances in these buildings. And also it'll fill in those gaps that are missing from the historical record."

Author: Jill Lawless | Source: The Associated Press [May 17, 2016]

"Heartbreaking" graffiti uncovered in a Cambridgeshire church has revealed how three sisters from one family died in a plague outbreak in 1515.

The names Cateryn, Jane and Amee Maddyngley and the date were inscribed on stonework in Kingston parish church.

It was found by Norfolk and Suffolk Medieval Graffiti Survey volunteers.

Archaeologist Matt Champion said the project had shown church plague graffiti was "far more common than previously realised".

"The most heartbreaking inscriptions are those that refer to long-dead children," he said.

The Maddyngley graffiti is hidden under limewash near the door in All Saints' and St Andrew's church.

The family lived in Kingston, seven miles from Cambridge, and were tenant farmers who "rarely turn up in parish records", he said.

Mr Champion believes Cateryn, Jane and Amee must have been children because their names are not found as adults in any of the records.

In 1515, there was an outbreak of bubonic plague in London which spread across south east England.

Mr Champion said Cambridge University suspended its classes and large gatherings of people were banned, "just as we see today with the Ebola outbreaks in Africa".

Children were particularly hard-hit and usually hastily buried in unmarked graves.

The graffiti survey was set up in 2010 and is the first attempt to survey pre-Reformation graffiti in churches since the late 1960s.

Volunteers use digital cameras and powerful lamps to reveal previously hidden or faded markings.

At least 60% of the 650 churches surveyed in Norfolk, Suffolk and north Essex have "significant amounts" of graffiti and volunteers have recorded up to 500 pieces in many of them.

The project has confirmed more graffiti is found to have been created during times of pestilence such as the Black Death of 1349 and subsequent outbreaks of plagues.

"It was a votive offering at a time where prayer counted," Mr Champion said.

Source: BBC News Website [February 21, 2015]

Scientists have found the oldest fossils of the familiar pine tree that dominates Northern Hemisphere forests today.

Scientists from the Department of Earth Sciences at Royal Holloway, University of London have found the oldest fossils of the familiar pine tree that dominates Northern Hemisphere forests today.

The 140-million-year-old fossils (dating from the Cretaceous 'Age of the Dinosaurs') are exquisitely preserved as charcoal, the result of burning in wildfires. The fossils suggest that pines co-evolved with fire at a time when oxygen levels in the atmosphere were much higher and forests were especially flammable.

Dr Howard Falcon-Lang from Royal Holloway, University of London) discovered the fossils in Nova Scotia, Canada. He said: "Pines are well adapted to fire today. The fossils show that wildfires raged through the earliest pine forests and probably shaped the evolution of this important tree." Modern pines store flammable resin-rich deadwood on the tree making them prone to lethal fires. However, they also produce huge numbers of cones that will only germinate after a fire, ensuring a new cohort of trees is seeded after the fire has passed by."

The research is published in the journal Geological Society of America.

Source: University of Royal Holloway London [March 10, 2016]