Fossils are one of the best ways for us to gain knowledge about evolution of species. However, they often lack detail and regardless of how many fossils scientists reveal, some mysteries remain. Now only the last meal of the extinct predatory fish Saurichthys helped scientists from the University of Zurich to see the shape of the intestines of this fish. This finally allowed science to close the gap in the knowledge about the evolution of the gastrointestinal tract in vertebrates.
The last meal of this fish revealed that intestines of Saurichthys are spiral-shaped. It is astonishing case of preservation that allowed scientists to make this discovery. Both digested and undigested remains of the last meal of this fish were visible. Scientists used these fossilized gut contents and prepared the first complete documentation on the gastrointestinal anatomy of this primitive vertebrate. The fossil came from the repository in Monte San Giorgio in Ticino. Scientists analysed preserved gut contents using UV light. To place their findings into the evolution of gastrointestinal tract in vertebrates, scientists assembled a large dataset containing information on extinct and extant fishes.
Researchers also performed other statistical analyses that helped to reveal until now unknown patterns of distribution of the intestinal structure. Researchers concluded that Saurichthys had a straight stomach and a spiral valve. Findings of the research revealed unexpected convergences with the gastrointestinal anatomy of present-day sharks and rays.
Thodoris Argyriou, one of the palaeontologists from the University of Zurich, said: “the anatomy of the gastrointestinal tract of Saurichthys, in particular the many windings in the spiral valve, show the most original digestion organs of earlier fishes. The large number of windings increased the surface area for digestion, which is sure to have provided the fish with more energy”. This means that Saurichthys needed a lot of energy, which was required by the lifestyle of the predator.
Many fossils are still not examined and many are still hiding in the ground. Therefore, we can expect many new discoveries in the future.