Paleontologist Lene Liebe Delsett remembers well the first time she saw the fossil in the museum in Germany.
Fish lizards are her specialty, but she has never seen a fully preserved fossil since that time.
– The more you see, the happier you are in this animal. She told NRK that I had a strong feeling that she was at the bottom of the sea, and it was an animal with its own history.
Lenny Libby Dilsett is the lead author of the article Searching for the Unusual Fossil.
Photo: Karsten Sund / University of Oslo
The fossil dates back to the late Jurassic, the geological period when dinosaurs and other large reptiles such as lizards and fish dominated our planet.
The typical remains of a prehistoric organism are bones and bones. But this fossil is a complete and almost complete body. In fact, the fish lizard is in such good condition that the remnants of the soft tissues of the body have been taken care of.
Unique study
Now, Lene Liebe Delsett, along with fellow researchers from Norway, Denmark and Germany, have conducted the first comprehensive study of the soft tissues of a fish lizard of this species.
consequences the study It was published in the famous PeerJ – the Journal of Life & Environmental Sciences.
BleedThe skepticism of these ancient remains is rarely a commodity. Only in a special region of Germany do we find such well-preserved fossils
The fish lizard was excavated at Solnhofen in Bavaria in 2009. 150 million years ago, this was a completely different place than it is today.
– The area looked like a tropical paradise, with islands and shallow lagoons, says Delsette.
This is how a fish lizard might look in its natural environment.
Illustration: Daniel Eskridge / Getty Images / iStockphoto
Named after the Norse god of the sea
Researchers believe that the fossil that was found belongs to the genus Egyrosaurus. This group of marine reptiles is named after Norse mythology. The family is named after the god of the sea and Jotun-Ager, who rules the sea.
Although the name is cool, the animal itself wasn’t the big crab. The fossil is the size of a small dolphin.
The swimming reptile is about 1.6 meters long, and probably lived on squid and fish. Large eyes indicate that they look good in the dark, as in deep water. The streamlined body shows that the animal may have been able to swim at a high speed.
Therefore, the discovery of the fossil in shallow water is a small mystery to scientists.
But the fact that the fish lizard found its last resting place here, is also the reason for its unique preservation.
Fish lizards of the genus Aegirosaurus were not very large.
Illustration: Wikimedia Commons
nature mummy
Lene Liebe Delsett says that nature itself created a kind of mummy forever.
The fish lizard may have been quickly buried in fine-grained sediments. This shuts down the oxygen supply and prevents decay.
In addition, there was a lot of lime in the precipitate, which gave a high pH value. The water may also have been too salty.
All these factors prevented the development of bacteria that could break a corpse.
Although the soft tissues of the body were preserved from the fossil, it became very different from what it was when the animal was alive.
The fish lizard fossil is on display in a museum in Bavaria, Germany.
Photo: Jura Eschstatt Museum / University of Oslo
Soft became hard
Over millions of years, the soft tissues have changed and become hard.
The researchers were allowed to examine the soft tissues of some of the small pieces that had fallen off when excavating the fossil. These fragments were examined with advanced x-rays and electron microscopy.
The mineral that forms in the soft tissues is called apatite, and researchers believe it is caused by phosphorous that was found in the body of a fish lizard.
The pieces the researchers examined likely consisted of skin, connective tissue, and lard.
Bacon means heat
A prehistoric lizard with lard is interesting to us paleontologists, Aubrey Jane Roberts tells NRK.
Aubrey Jane Roberts has excavated marine fossils on Svalbard.
Photo: Frida J. Krüger / NRK
She works at the Natural History Museum in Oslo, and has worked a lot with fossil reptiles in the sea. Roberts says the discovery of lard can tell us a lot about how the fish lizard lives.
Bacon is an insulating layer of fat, and many modern seawater mammals have fat on their bodies.
The fat indicates that the fish lizard, like mammals, was able to produce its own heat. Thus, the lizard is likely to live and work in cold water. Bacon is not at all common for reptiles today, and most of it depends on the heat from the surrounding environment.
In other words, it is no coincidence that crocodiles live in Africa and not in Norway, says Roberts.
The ability to take care of body heat is not the only similarity between a fish lizard and marine mammals today.
Teeth and large eyes are visible in the fossa.
Photo: Jura Eschstatt Museum / University of Oslo
puzzlingly like a dolphin
The fossil has a strikingly similar appearance to today’s dolphins, despite the fact that they became extinct millions of years before whales evolved.
Lene Liebe Delsett says this is a clear example of the so-called convergent evolution. The environment and ocean at sea have changed little over the ages.
Therefore, both terrestrial reptiles and mammals evolved similar bodies when evolution adapted them to life in the sea.
In part, I hope it will be possible to do more research on the fossils in Germany, because the fish lizard has also preserved parts of its digestive system.
If we could learn more about stomach contents and what they eat, it could tell us more about how the fish lizard lives. Thus, we can also learn more about the differences and similarities with marine mammals today, says Lene Liebe Delsett.
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