Reading About 30 million years after the first vertebrates conquered the land, herbivores spread more and more. This development was made possible by the invention of chewing, Robert Reisz from the University of Toronto in Canada and Natalia Rybczynski from Duke University in North Carolina in the journal Nature. The oldest reptile that perfected the tumbling of hard, fibrous plant parts was Suminia getmanovi, a 30-centimeter-long animal with large eyes and impressive teeth.

Reisz and Rybczynski examined the teeth of a specimen of Suminia found in Russia with the electron microscope and discovered there ridges, which suggested that the animal shredded vegetable food by shearing movements of the jaw. In contrast to many reptiles living today - such as lizards and crocodiles - the teeth of upper and lower jaw of Suminia meet.

The ability to effectively downsize hard stems and leaves helped Suminia make better use of the nutrients contained in plants. This led for the first time to the larger spread of the then living herbivorous vertebrates, the so-called Anomodonta. The ability to chew also revolutionized the structure of the ecosystem: Before the invention of chewing, there were very few herbivores. Most of the vertebrates living at that time fed on invertebrates. There were also predators that fed on the former.

With the spread of herbivores, the modern form of the ecosystem, in which few predators feed on many herbivores, became established. display

Ute Kehse

© science.de

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