(CN) — Researchers examined the fossilized remains of fish-like marine reptiles whose blubber and soft tissues were preserved approximately 150 million years ago.
A study published Thursday in the journal PeerJ describes the fossils, which are from Ichthyosaurs — extinct marine reptiles that lived alongside the dinosaurs and resemble dolphins and whales. Excavated from a site in southern Germany famous for its well-preserved fossils from the late Jurassic period, the specimens include a complete skeleton with an outline of the soft tissue around the body, as well as a complete tail fin that also had its soft tissues preserved.
Lead author of the study Lene Liebe Delsett, a marine reptile paleontologist at the University of Oslo in Norway, said though the research team is still not sure about all of the fossil contents, they are confident they have identified some interesting findings within the animals’ remains.
“We think it’s at least partly blubber and partly skin,” said Delsett. “Sometimes when you do research, you have a lot of data, you have a lot of specimens, so you can do large time series. In this case, we have one specimen with a lot of information in it and it can tell the entire story and that is why this is so special.”
Working with a mineralogist, the researchers examined the composition of the fossilized matter around the skeleton to verify if was part of the ichthyosaur or just mud or soil. The phosphate content led them to the conclusion that it came directly from the animal. In effect, the ichthyosaur is buried in its own blubber.
Blubber is the thick fatty layer found in many marine mammals today. Scientists have previously discovered that ichthyosaurs had blubber, but questions remain about the similarities between the Jurassic marine reptiles and the marine mammals seen today.
“For me, it’s interesting for the comparison to whales and dolphins because it’s very well-known that they have the same body shape, but then they also have some other revolutionary innovations like blubber,” said Delsett.
Though the site in Germany, Solnhofen, is known for its well-preserved fossils of bird-like dinosaurs that dwelled in the area millions of years ago, Ichthyosaur fossils are not common there. During the late Jurassic, the area was primarily a series of small islands surrounded by lagoons. Ichthyosaurs largely dwelled in the open ocean, so there are lingering questions about why they were in Solnhofen and how they died. One hypothesis Delsett suggested is that the area was too salty.
Delsett said the completeness of the specimen could allow future studies to investigate the other soft tissues of ichthyosaurs, such as muscles, organs or the contents of their stomachs. According to Delsett, this could illuminate what the ichthyosaurs ate and how they swam.
Another of Delsett’s takeaways from the research was the value of working with an interdisciplinary array of scholars.
“It made a broader range,” Delsett said. “In the paper, we can do chemical composition things, but we also discussed the classical description of a skeleton. It broadens our scope.”
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