True colours: chameleons probably originated in Madagascar
Reptile history reveals daring escape from Madagascar
Land-lubber chameleons navigated the oceans to spread around the world. Stowed away on tree rafts, the animals were ferried to distant shores, new research suggests1.
Chameleons aren’t good swimmers: their mitten-like feet are made to grasp twigs and trees. Yet the intrepid animals charted the seas several times in the past 26 million years, say Chris Raxworthy of the American Museum of Natural History in New York, and his colleagues.
"It’s pretty bold," says Olivier Rieppel, who studies reptile evolution at the Field Museum in Chicago, Illinois, because it seems counter-intuitive. "It’s hard to imagine an animal swimming more awkwardly," he says.
The lizards’ most likely escape route was an upturned tree, says Rieppel, or chunks of land chewed off by waves. There are also suggestions that a land bridge once linked Madagascar and mainland Africa - in which case the reptiles might have strolled across.
Land or sea
Raxworthy’s idea counters previous accounts of chameleon history: that they originated on the ancient supercontinent Gondwana and were divided when the land mass split.
India and Madagascar together broke away from Africa 165 million years ago; Madagascar and the Seychelles subsequently separated from India. These events occurred long before chameleons first appeared on the planet - 26 million years ago, according to fossil records.
Many other animal and plant species are thought to have evolved when the movement of continental plates created barriers such as seas and mountains. Divided by water or crag, populations are thought to have evolved into new, related species.
This type of hypothesis can be tested by marrying evolutionary trees with geological records
Dispersal hypotheses such as Raxworthy’s are more difficult to check: "There’s a lot more speculation," says Mark Springer at the University of California in Riverside.
Springer recently showed that the earliest split of the placental mammals into two basic groups coincides with the separation of South America and Africa around 100 million years ago2. Researchers accept that continental movements and ocean navigation play a role in species dispersal. "They’re both very important," says Springer.
HELEN PEARSON | © Nature News Service
Rutgers scientists discover 'Legos of life'
23.01.2018 | Rutgers University
Researchers identify a protein that keeps metastatic breast cancer cells dormant
23.01.2018 | Institute for Research in Biomedicine (IRB Barcelona)
Physicists have developed a technique based on optical microscopy that can be used to create images of atoms on the nanoscale. In particular, the new method allows the imaging of quantum dots in a semiconductor chip. Together with colleagues from the University of Bochum, scientists from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute reported the findings in the journal Nature Photonics.
Microscopes allow us to see structures that are otherwise invisible to the human eye. However, conventional optical microscopes cannot be used to image...
On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.
We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
23.01.2018 | Life Sciences
23.01.2018 | Earth Sciences
23.01.2018 | Physics and Astronomy