Major Viking hall identified in Sweden

Using ground-penetrating radar. Credit: Martin Rundkvist

A Viking feasting hall measuring almost 50 metres in length has been identified near Vadstena in Sweden. Archaeologists from Stockholm University and Umeå University used ground-penetrating radar, a non-invasive geophysical method, to locate and map the house foundation. The study was published today in the journal Archaeological Prospection.

The Aska barrow, where the hall has been found, was long seen as a burial mound. But archaeologists have now revealed that it is a foundation platform for a large building, most likely dating from the Viking Period. The hall was probably the home of a royal family whose rich graves have previously been excavated nearby.

"Parallels are known from several of the era's elite sites, such as Fornsigtuna near Stockholm and Lejre near Roskilde. The closest similarities are however seen in a recently excavated feasting hall at Old Uppsala near Stockholm. Such close correspondences suggest intensive communication between the two sites," says Martin Rundkvist of Umeå University

The building was about 14 metres wide and was equipped with double walls and four entrances. The measurements also indicate a large fireplace at the centre of the floor.

"Our investigation demonstrates that non-invasive geophysical measurements can be powerful tools for studying similar building foundations elsewhere. They even allow scholars to estimate the date of a building without any expensive excavations," says Andreas Viberg of the Archaeological Research Laboratory at Stockholm University who directed the fieldwork.

Source: Stockholm University

A taxonomic toolkit ends a century of neglect for a genus of parasitic wasps

This is Ophion keala, one of the newly described species of Ophion." Credit: Dr. Marla Schwarzfeld; CC-BY 4.0

In 1912, three species in the parasitic wasp genus Ophion were described by two different entomologists, increasing the number of known species in North America to eleven. It has long been known that the actual diversity is much higher; however, it took 102 years for any additional species to be described.

"The main reason for this is that everyone has assumed that Ophion are just too difficult to tell apart. Museum collections are full of unidentified Ophion, but nobody has wanted to face the challenge of sorting them out" said Marla Schwarzfeld, an entomologist who recently completed her Ph.D. at the University of Alberta, Canada.

In fact, the author of one of the species described in 1912, Claude Morley, stated: "Without abundant material it were ridiculous to attempt a wide revision of these insects; and ... a mass of this material causes one's courage to sink at the sight of so uniform and apparently characterless a group."

However, with the advent of new taxonomic tools, it is no longer necessary to rely solely on the challenging morphology of the group. Schwarzfeld and her Ph.D. supervisor, Felix Sperling, used a combination of molecular and morphometric analyses to define a new species group within Ophion, and to delimit and describe six new species within this group. The molecular work involved the analysis of three different genetic markers, while the morphometric analyses included both an analysis of wing venation and a more traditional approach of measuring various body parts. The study, including the new descriptions, has recently been published in the open-access journal, ZooKeys.

"The exciting part about this work is that these techniques all gave remarkably congruent results, which gives us a lot of confidence in these new species. This takes a lot of the guesswork out of describing species, and will be a really valuable toolkit for studying additional species of Ophion, as well as species in other morphogically-challenging groups" declared Schwarzfeld.

Source:  Pensoft Publishers

New insights into origins of agriculture could help shape future of food

Wheat field (stock image). Agricultural decisions made by our ancestors more than 10,000 years ago could hold the key to food security in the future, according to new research by the University of Sheffield. Credit: © igor / Fotolia

Agricultural decisions made by our ancestors more than 10,000 years ago could hold the key to food security in the future, according to new research by the University of Sheffield.

Scientists, looking at why the first arable farmers chose to domesticate some cereal crops and not others, studied those that originated in the Fertile Crescent, an arc of land in western Asia from the Mediterranean Sea to the Persian Gulf.

They grew wild versions of what are now staple foods like wheat and barley along with other grasses from the region to identify the traits that make some plants suitable for agriculture, including how much edible seed the grasses produced and their architecture.

Dr Catherine Preece, who worked on the study with colleagues from the University's Department of Animal and Plant Sciences and Department of Archaeology, said: "Our results surprised us because numerous other grasses that our ancestors ate, but we do not, can produce just as much seed as wild wheat and barley. It is only when these plants are grown at high densities, similar to what we would find in fields, that the advantage of wild wheat and barley is revealed."

The study identified two key characteristics shared by the wild relatives of current crop plants. Firstly they have bigger seeds, which means they grow into bigger seedlings and are able to get more than their fair share of light and nutrients, and secondly, as adult plants they are less bushy than other grasses and package their big seeds onto fewer stems. This means crop wild relatives perform better than the other wild grasses that they are competing with and are better at growing close together in fields, making them ideal for using in agriculture.

"The results are important because our expanding human population is putting increasing demands on food production," said Dr Preece.

"Before humans learnt how to farm, our ancestors ate a much wider variety of grasses. If we can understand what traits have made some grasses into good crops then we can look for those characteristics in other plants and perhaps identify good candidates for future domestication."

She added: "To shape the future we must understand the past, so the more we can discover about the origins of agriculture, the more information we will have to help us tackle the challenges that face modern day food production."

So far the researchers have been conducting their experiments in greenhouses and their results indicate that the traits affecting how plants compete with each other are crucial factors to determining the success of a crop.

The team now plan to observe how the plants interact in their natural environment by growing them in experimental fields in Turkey, the heart of the Fertile Crescent. They hope that their experiments will yield another crop of important results.

"Cereal breeders are taking an increasing interest in modern crops' wild relatives as a source of useful traits that may help to increase yields or increase resilience to climate change, and our work should help in this process," said Dr Preece.

Dr Preece presented the results of this study to the joint British Ecological Society and the French Ecological Society 11 December 2014 in the Grand Palais, Lille.

Source: University of Sheffield