Digital skull model of the small-sized Jurassic mammal ancestor Hadrocodium wui. Credit: Dr Stephan Lautenschlager, University of Birmingham
Phys.org has a story about the evolution of mammals. A new paper in the journal Communications Biology, found that being small led to more efficient feeding, The international team of paleontologists used computer analysis and stress analysis to understand the process of skull simplification in early mammals. In mamy vertebrate groups, like fish and reptiles, the skull and lower jaw is comprised of numerous bones. Mammals reduced the number of skull bones during the Mesozoic from around 150 to 100 million years ago.
Lead author Dr. Stephan Lautenschlager, Senior Lecturer for Palaeobiology at the University of Birmingham, commented, "Reducing the number of bones led to a redistribution of stresses in the skull of early mammals. Stress was redirected from the part of the skull housing the brain to the margins of the skull during feeding, which may have allowed for an increase in brain size.
"Changes to skull structure combined with mammals becoming smaller are linked with a dietary switch to consuming insects—allowing the subsequent diversification of mammals which led to development of the wide-range of creatures that we see around us today."
The study further demonstrated that alongside the reduction of skull bones, early mammals also became a lot smaller, some of which had a skull length of only 10–12 mm. This miniaturization considerably restricted the available food sources, and early mammals adapted to feeding mostly on insects.
