(LINKS TO PAST FOSSIL FRIDAYS)
Community College (LRCCD)
Geology & Earth Science Instructor: Arthur
Reed, P.G.
Happy Fossil Friday!
Friday October 22, 2021
The Oldest Airborne Vertebrate Animal Was
a Reptile With Weird Wings
Artistic reconstruction of Weigeltisaurus jaekeli.
Proportions and anatomy after Pritchard et
al. (2021).
Before dinosaurs ruled Earth, there
were many small and fascinating reptiles.
One was the Weigeltisaurid in the late Permian around 255 million years
ago. Fossils of this animal have been
found in several locations around the world but only recently has one been
examined closely enough to understand that it was likely the earliest airborne
vertebrate. A fossil found in Germany in
1992 and stored in a German museum has now been analyzed by Smithsonian
paleontologists. They determined its
strange bone structure’s purpose was to support a thin membrane that gave it
the ability to glide through the air likely from one tree to another or to
simply parachute down. The Smithsonian article announcing the finding is
included below.
NATIONAL MUSEUM OF NATURAL HISTORY
The Oldest Airborne Vertebrate Animal Was a Reptile
With ‘Weird’ Wings
Paleontologists describe a
255-million-year-old weigeltisaurid fossil that likely glided through the air
with the help of expansive winglike membranes
October
13th, 2021
Scientists pulled this weigeltisaurid fossil out of an outcropping
of copper shale in Germany in 1992. Now, Smithsonian paleontologists have fully
described this animal, the oldest known vertebrate capable of gliding through
air. Pritchard et al. 2021
Since the Middle Ages,
humans have mined a rich deposit of shale stretching across Europe for copper,
zinc, silver and fossils. In 1992, a fossil collector
in eastern Germany pulled a strange skeleton out of the mining refuse from this
rocky layer. It had a pointy crown of horns, thin
limbs and peculiar rods stretching out from its chest.
These are a really weird set of bones. They do not seem to exist in
pretty much any other vertebrate animal, said Adam Pritchard, an assistant
curator of paleontology at the Virginia Museum of Natural History and former
Peter Buck postdoctoral fellow at the Smithsonian National
Museum of Natural History.
The fossil, it turns out,
is an ancient reptile named Weigeltisaurus jaekeli, a reptile that
lived over 250 million years ago before the dinosaurs. Pritchard and Hans-Dieter Sues, curator of vertebrate
paleontology at the museum, have published a new detailed analysis of the specimen in
the scientific journal PeerJ. They posit that the
animal, known as a weigeltisaurid, used those bony rods to support winglike
membranes used for gliding, making it the oldest-known airborne vertebrate
animal.
Weigeltisaurus jaekeli likely used its wide, winglike
membranes to glide from branch to branch in the late-Permian
forest. Paleontologists reconstructed the reptile’s anatomy in this
drawing to illustrate its skeleton’s proportions. Pritchard et al. 2021
A strange specimen
The fossil hunter found
the strange skeleton by splitting pieces of shale, cracking the fossil
into two slabs. One slab ended up in the hands of a private collector and
likely contains pieces of the reptile's bones. The other slab held most of the
skeleton and landed in the collection of the State Museum of Natural
History in Karlsruhe, Germany. Scientists pinpointed the fossil in the second
slab as a Weigeltisaurus, which was first described from another
fossil in 1930, but the reptile's body shape still remained
an enigma to paleontologists.
Over the years, some
researchers suggested that the long bones protruding from the specimen’s
abdomen could have allowed the animal to glide through the air like a flying
squirrel. But the skeleton in the fossil is curved in on itself and some bones
are overlapping, making it hard to tell if they’re just ribs, or something
else.
Researchers cleaned the Karlsruhe fossil to expose its bones more
clearly before analysis. The positioning makes it difficult to deduce the
function of the long horizontal bones pictured at the fossil’s center. Diane Scott
“There are very few
things like it,” Sues said of the fossil. A few other specimens from the same
species have also been unearthed in England, Russia
and Madagascar, but the fossil housed in the Karlsruhe Museum provides the most
complete example of the animal’s anatomy. “This is definitely the one that
brings it all together,” Pritchard said.
Pritchard saw the
skeleton referenced in the scientific literature over the years as a grad
student researching the evolution of early reptiles during the Permian Period,
which lasted between 299 and 251 million years ago. “But no one had really gone
in and done a very fine, detailed analysis of the skeleton of these animals.” When Pritchard
came to the Smithsonian as a postdoc in search of a meaty project to dig his
teeth into, Sues suggested he take a closer look at
the weigeltisaurid.
Quality fossil time
Pritchard flew to
Germany for a week to pore over the fossil at its home in the Karlsruhe museum’s
collections. ”I'm of the mind that if you're going to
make a fossil the focus of a study you should spend a very large amount of
quality time with it in person, ” he said.
He took pages of copious
notes, making an inventory of all the individual bones and building his own
interpretation of how they all might fit together. ”And
then I photographed the heck out of it, ”Pritchard said, to be sure he wouldn’t
miss one tiny detail in the bones once he came back to the Smithsonian.
The weigeltisaurid specimen used in the bulk of Pritchard and
Sues’ study is housed in the State Museum of Natural History in Karlsruhe,
Germany. Adam Pritchard
After painstakingly
measuring every rib, finger and toe, Pritchard laid out the weigeltisaurid”
bones in several
drawings and diagrams. He also mapped where the animal might fit on the reptile
family tree by comparing each of its anatomical traits with those of other
ancient lizards. Though it probably looked something like a chameleon, the
weigeltisaurid belongs to an evolutionary line that split off from the lizards,
crocodiles and snakes we know today.
”These are a more ancient lineage than any of those
animals,” Pritchard explained.
Unique gliders
Initially, Pritchard
looked at this project as a chance to explore a curious fossil on a deep level.
”But as I got into the work, it became clear to me
that there was one question that kind of remained. And that is the identity of
the bones that seem to have formed the gliding membrane,” he said.
Pritchard and his
colleagues’ analysis shows that there are more wing
bones than vertebrae and that they lay separate from the rest of the skeleton,
confirming that they would have supported two wide flaps extending from each
side of the animal’s abdomen. This is a singular trait, Sues
explained. There are gliding lizards that exist today, but their ‘wings’ are
attached to their ribs, he said.
While Pritchard and Sues
are confident that weigeltisaurids were gliders, there’s not a lot else known about
the animal’s life history. ”I would love to know how
they grew,” Pritchard said. ”What did it look like
when it popped out of the egg?” He also wonders about what the weigeltisaurid
snacked on. His best guess is bugs, but he can’t be totally sure unless some
direct fossil evidence turns up. ”We don’t have a
weigeltisaurid with insect material inside its abdominal region. But that would
be cool,” Pritchard said.
Though he’s not
currently working on these questions, Pritchard said that learning more about
weigeltisauird and its relatives can give us a better appreciation for the
diversity of reptiles - even before dinosaurs came on the scene. ”Among paleontologists there’s this sense that once you get
into the age of dinosaurs, that’s when reptiles really take off, develop all
kinds of amazing features and just come into their own,” he said. But earlier
animals like Weigeltisaurus are proof that reptiles have
always been ”super weird,” he explained. ”They’re doing strange things that, if we didn’t have the
fossils, we never would have expected. ”
Tess
Joosse | | READ MORE
Tess Joosse is an intern in the Smithsonian National Museum of
Natural History’s Office of Communications and Public Affairs. Her writing
has appeared in Science, Scientific American, Inside Science, Eos, Mongabay and
the Mercury News, among other outlets. Tess recently graduated from the
University of California, Santa Cruz with an MS in science communication. She
also holds a BA in biology from Oberlin College. You can find her at https://www.tessjoosse.com/.
(and: NATIONAL MUSEUM OF NATURAL HISTORY)