Coprolites, or fossil droppings, of the dinosaur-like dinosaur Smok Wawelski contain many chewed bone fragments. This prompted researchers at Uppsala University to conclude that this top predator was exploring bones for salt and bone marrow, a behavior often linked to mammals but rarely to archosaurs.
Most predatory dinosaurs used their blade-like teeth to feed on the flesh of their prey, but they are generally not believed to be much of a bone crusher. The great exception is seen in the great tyrannosaurids, such as Tyrannosaurus rexwhich traversed North America towards the end of the dinosaur age. Tyrannosaurs are believed to have been osteophores (voluntarily exploiting bone) based on findings of bone-rich coprolites, bite-marked bones, and their sturdy teeth being commonly used.
In a study published in Scientific Reports, researchers at the University of Uppsala succeeded in linking ten large copro- Smok Wawelski, a top predator of an assembly of the Upper Triassic (210 million years) unearthed in Poland. This 5-6-meter-long bipedal animal lived about 140 million years before North American tyrannosaurs and had a T. rexlike appearance, although it is not entirely clear whether it was a true dinosaur or a dinosaur-like precursor.
Three of the coprolites were digitized using synchrotron microtomography. This method has recently been applied to coprolites and works as a CT scanner in a hospital, with the difference that the energy in the X-ray bundles is much stronger. This allows visualizing internal structures in fossils in three dimensions.
Coprolites were shown to contain up to 50 percent of the prey animal bones, such as large amphibians and juvenile dicinodonts. Several crushed serrated teeth, probably belonging to the coprolite itself, were also found in the coprolites. This means that the teeth have been repeatedly crushed against hard foods (and ingested involuntarily) and replaced with new ones.
Other evidence of bone-crushing behavior can also be found in the fossils of the same bony beds in Poland. These include frayed and regurgitated teeth rich in Smok Wawelski, as well as numerous crushed or marked bones.
Several of the anatomical characters related to osteophage, such as the bulky head and the robust body, appear to be shared by S. wawelski and tyrannosaurs, though they are distant relatives and live apart for 140 million years. These large predators, therefore, appear to provide evidence of similar feeding adaptations being acquired independently at the beginning and end of the dinosaur era.
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