Extinct animals hide their secrets well, but an exceptionally well-preserved fossil of an aquatic reptile, with traces of soft tissue present, is providing scientists a new window into the behavior of these ancient swimmers.
According to the study published in PLoS ONE's Nov. 16 issue, the fossil, characterized by a team led by Johan Lindgren of Lund University in Sweden, is from the mosasaur family, a group of reptiles that lived between 65 and 98 million years ago.
The fossil was found in Western Kansas, and was submerged under a shallow sea at the time of the mosasaur's existence. Previous analysis of mosasaur locomotion had been limited by a lack of soft tissue fossils, which was crucial for the scientists to truly understand the degree of aquatic adaptation that the creature had achieved. The new findings, which include scales and skin impressions, suggest that the mosasaur was able to minimize its frictional drag in the water. Additional features suggest that it held the front of its body somewhat rigid during swimming, leading it to depend on the rear of its body and tail for propulsion.
According to Dr. Lindgren, this study provides "unique insights into the biology of an extinct group of marine lizards that became adapted to aquatic environments in a fashion similar to that of the preceding ichthyosaurs ('fish-lizards') and succeeding whales." Thus, these results may have implications for understanding how this group ultimately transformed from land-dwellers to pelagic cruisers in a relatively short period of geological time.
Citation: Lindgren J, Everhart MJ, Caldwell MW (2011) Three-Dimensionally Preserved Integument Reveals Hydrodynamic Adaptations in the Extinct Marine Lizard Ectenosaurus (Reptilia, Mosasauridae). PLoS ONE 6(11): e27343. doi:10.1371/journal.pone.0027343
Thursday, November 17, 2011
Wednesday, May 4, 2011
Fossil – just stone? No, a research team in Lund, Sweden, has discovered primary biological matter in a fossil of an extinct varanoid lizard (a mosasaur) that inhabited marine environments during Late Cretaceous times. Using state-of-the-art technology, the scientists have been able to link proteinaceous molecules to bone matrix fibres isolated from a 70-million-year-old fossil; i.e., they have found genuine remains of an extinct animal entombed in stone.
With their discovery, the scientists Johan Lindgren, Per Uvdal, Anders Engdahl, and colleagues have demonstrated that remains of type I collagen, a structural protein, are retained in a mosasaur fossil.
The scientists have used synchrotron radiation-based infrared microspectroscopy at MAX-lab in Lund, southern Sweden, to show that amino acid containing matter remains in fibrous tissues obtained from a mosasaur bone.
Previously, other research teams have identified collagen-derived peptides in dinosaur fossils based on, for example, mass spectrometric analyses of whole bone extracts.
The present study provides compelling evidence to suggest that the biomolecules recovered are primary and not contaminants from recent bacterial biofilms or collagen-like proteins.
Moreover, the discovery demonstrates that the preservation of primary soft tissues and endogenous biomolecules is not limited to large-sized bones buried in fluvial sandstone environments, but also occurs in relatively small-sized skeletal elements deposited in marine sediments.
A paper reporting the discovery, Microspectroscopic Evidence of Cretaceous Bone Proteins is now available in the scientific journal PLoS ONE