flyboys

Look: Lasers help scientists finally solve Jurassic flight mystery

Move aside flyboys, this pterosaur is ready to tear up the skies.

Millions of years before the Wright brothers ever conceived the first airplane, a late Jurassic flying reptile was already soaring through the skies with mechanical-like precision.

With a maximum wingspan of over 30 feet — just shy of the Wright brother’s first flyer — the pterosaur was a sight to behold in the ancient skies and was the first vertebrate to use powered flight. However, while the skeletal remains of these flyboys have helped scientists piece together some idea of how they achieved flight, there are still many unknowns.

That could soon be changing, though, thanks to a discovery reported this Monday in the journal Proceedings of the National Academy of Sciences. By shining laser beams on a pterosaur skeleton, a team of researchers has now uncovered hidden details about the creature’s anatomy and wing performance that could help us reimagine how it took flight.

“Unlike bats and birds, the pterosaur wing root fairing was unique in being primarily made of muscle rather than fur or feathers,” the authors write. “This study underscores the value of using new instrumentation to fill knowledge gaps in pterosaur flight anatomy and evolution.”

Based on their laser analysis, the research team believes that their pterosaur specimen used a muscular wing root fairing to achieve additional flight performance benefits.Illustration by Alex Boersma

What’s new — While much larger than the birds and bats we know today, previous studies of pterosaur skeletons have identified that these vertebrates used similar techniques to propel them through the Jurassic skies.

Today, bats are the only surviving vertebrate flyer using powered flight, although birds and aircraft use a similar technique. This means that their wings help them overcome drag when flying. In addition to using the power of their wings to fly smoothly, birds and bats also have something called a “fairing” — essentially a fur or feather-covered curve between their neck and wing — that helps them cut through air resistance.

However, while scientists have known that pterosaurs use this powered flight technique, they didn’t know how the reptile’s anatomy helped them achieve it. For example, whether or not they had similar fairings to modern-day animals.

To answer this question, the team used a technique called laser-stimulated fluorescence to help them collect data on the soft tissue and bones of a pterosaur skeleton, which the authors write can appear misleading under full-spectrum white light.

Why it matters — Understanding the flight dynamics of this ancient creature can help scientists not only gain new insight into this period of history but could potentially help them better understand powered flight today. It may also help aerospace engineers find new inspiration when designing next-generation aircraft and drones.

Compared to the fairing of a bird or bat — as illustrated in the research paper — a pterosaur was likely more muscular. Pittman et al. / PNAS

What they did — To start their work, the research team borrowed a pterosaur skeleton from a paleontology museum in Munich, Germany. The specimen had initially been recovered from German limestone in 1937 and had a fully articulating skeleton.

The team then took this specimen into a dark room and lit it up using a 405-nanometer blue light laser. Far from being strong enough to damage the skeleton, this light allowed the researchers to collect a geochemical signature from the remains that determined whether a sample was soft tissue or not. If the sample was soft tissue, like a muscle, it would glow pink under the blue light.

Spontaneously fluorescence like this may seem otherwordly, but it’s very similar to the experience of walking under ultra-violet light and seeing your fingernails or teeth glow bright white.

Under the light of a blue laser, the pterosaur’s soft tissue glows pink.Image credit: Michael Pittman.

Collecting these pink-hued photos with a highspeed camera, the researchers were able to make some confident claims about the gains of this ancient flying reptile.

“We interpret the imaged soft tissue making up the fairing as being primarily composed of skeletal muscle,” the authors write. “The skeletal muscles could have contributed to continuous, active camber and flutter control throughout the wing stroke or reduced span.”

This means that unlike bats and birds, whose wing fairings are mostly fur and feathers, the pterosaurs might’ve been closer to sheer muscle. The team speculates this would’ve given the pterosaur more sophisticated control over its wing’s stroke and shape.

What’s next — This specimen is imperfect and can’t give scientists a full glimpse into its past life. However, the researchers say that the data they gleaned from it is nevertheless a promising example of how this technique could be used in the future.

“Our study underscores the power of new instrumentation in improving our understanding of pterosaur flight anatomy and evolution.”

Abstract: Pterosaurs were the first vertebrate flyers and lived for over 160 million years. However, aspects of their flight anatomy and flight performance remain unclear. Using laser-stimulated fluorescence, we observed direct soft tissue evidence of a wing root fairing in a pterosaur, a feature that smooths out the wing–body junction, reducing associated drag, as in modern aircraft and flying animals. Unlike bats and birds, the pterosaur wing root fairing was unique in being primarily made of muscle rather than fur or feathers. As a muscular feature, pterosaurs appear to have used their fairing to access further flight performance benefits through sophisticated control of their wing root and contributions to wing elevation and/or anterior wing motion during the flight stroke. This study underscores the value of using new instrumentation to fill knowledge gaps in pterosaur flight anatomy and evolution.
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