It was previously proposed that Anacardium and its African sister genus, Fegimanra, diverged from their common ancestor when the landmasses of Africa and South America separated. However, groundbreaking new data in the October issue of the International Journal of Plant Sciences indicate that Europe may be an important biogeographic link between Africa and the New World.
“The occurrence of cashews in both Europe and tropical America suggests that they were distributed in both North America and Europe during the Tertiary and spread across the North Atlantic landbridge that linked North America and Europe by way of Greenland before the rifting and divergence of these landmasses,” explain Steven R. Manchester (University of Florida), Volker Wilde (Forschungsinstitut Senckenberg, Sektion Palaeobotanik, Frankfurt am Main, Germany), and Margaret E. Collinson (Royal Holloway University of London, UK). “They apparently became extinct in northern latitudes with climatic cooling near the end of the Tertiary and Quaternary but were able to survive at more southerly latitudes.”
The cashew family (Anacardiaceae) includes trees, shrubs, and climbers prominent in tropical, subtropical, and warm temperate climates around the world. A key feature is an enlarged hypocarp, or fleshy enlargement of the fruit stalk, which is a specialized structure known only in the cashew family.
The researchers examined possible fossil remains found in the Messel oil shales, near Darmstadt, Germany, which are dated to about 47 million years before the present and reveal the presence of a “conspicuously thickened” stalk. In four out of five specimens, this hypocarp was still firmly attached to the nut, indicating that the two were dispersed as a unit. According to the researchers, the size and shape of the hypocarp – like a teardrop and two or three times longer than it is wide – support its assignation to the Anacardium genus, common to South America, rather than the African Fegimanra genus, though the fossils have features common to both.
“The occurrence of Anacardium in the early Middle Eocene of Germany suggests . . . that the two genera [Anacardium and Fegimanra] diverged after dispersal between Europe and Africa,” the researchers write. “Presumably, Anacardium traversed the North American landbridge during the Early or Middle Eocene, at a time of maximal climatic warmth, when higher latitudes were habitable by frost-sensitive plants.”
The astoundingly close similarity between the fossil and modern day Anacardium also indicates little evolutionary change to the cashew since the mid-Eocene period: “Although cashews have been cultivated for human consumption for centuries, it is clear that they were in existence millions of years before humans. The cashew had already evolved more than 45 million years ago, apparently in association with biotic dispersers,” they write.
Suzanne Wu | EurekAlert!
Bacteria as pacemaker for the intestine
22.11.2017 | Christian-Albrechts-Universität zu Kiel
Researchers identify how bacterium survives in oxygen-poor environments
22.11.2017 | Columbia University
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
22.11.2017 | Business and Finance
22.11.2017 | Physics and Astronomy
22.11.2017 | Physics and Astronomy