Origin of birds mitochondrial uncoupling protein, UCP1, which is thermogenic. In mammals, UCP1 functions within brown adipose tissue to protect newborns against hypothermia. In modern birds, skeletal muscle serves a similar function and is presumed to have done so in their ancestors. In this view, bipedality and other avian skeletal alterations were side effects of muscle hyperplasia, with further evolutionary modifications of the forelimbs, including adaptations for flight or swimming, and vestigiality, being secondary consequences of two-leggedness. "Archaeopteryx" has historically been considered the first bird, or "Urvogel". Although newer fossil discoveries filled the gap between theropods and "Archaeopteryx", as well as the gap
Specimens of Archaeopteryx first time with six other original fossils of "Archaeopteryx" at the "Munich Mineral Show" in October 2009. A first, quick look by scientists indicates that this specimen might represent a new species of "Archaeopteryx". It was found in a limestone bed that was a few hundred thousand years younger than the other finds. The eighth specimen of "Archaeopteryx" was officially announced in February 1996 at a special exhibition at Bavaria’s Naturkunde Museum. Its director, Matthias Mäuser, made the announcement to a surprised audience that the specimen had already been casted and that this was on display in the exhibit. Few