( CNN ) -- Scientists say a very rare find of some 20 fossilized pterodactyls has produced the first clear evidence of a controversial theory of evolution . This image shows the fossilized skeleton of Darwinopterus which was found in north-east China earlier this year . The fossils were found in northeast China earlier this year , embedded in rock dating back 160 million years , and have been called `` Darwinopterus '' after the renowned naturalist Charles Darwin . The creature 's discovery has astounded scientists because their age puts them within two recognized groups of pterodactyls -- primitive long-tailed forms and advanced short-tail forms -- and they display characteristics of both . The combination of features indicates that the primitive pterodactyls evolved relatively quickly , and that certain groups of features changed at the same time . Traditional evolutionary theory suggests that one feature -- a tail for instance -- would slowly evolve over time . `` Darwinopterus came as quite a shock to us , '' said David Unwin , from the University of Leicester 's School of Museum Studies , which identified the creature , along with researchers from the Geological Institute of Beijing . `` We had always expected a gap-filler with typically intermediate features such as a moderately elongate tail -- neither long nor short -- but the strange thing about Darwinopterus is that it has a head and neck just like that of advanced pterosaurs , while the rest of the skeleton , including a very long tail , is identical to that of primitive forms , '' he said . By comparing the fossil with others from earlier and later periods , scientists have been able to sketch a rough timeline of the pterodactyl 's progression . `` The head and neck evolved first , followed later by the body , tail , wings and legs , '' Unwin said . The researchers say more study is needed to substantiate the idea of that evolution could occur relatively quickly , and that whole parts of a plant or animal 's body could change at once . The fossils indicate Darwinopterus was about the size of a crow , with long jaws , sharp , pointed teeth and a flexible neck . It had `` hawk-like '' qualities , scientists say , which allowed the creature to kill and eat smaller , feathered dinosaurs which would later evolve into birds . Pterodactyls were prevalent during the Mesozoic Era between 220 and 65 million years ago . The research has been published in the `` Proceedings of the Royal Society B : Biological Sciences . ''
Researchers say rare fossil evidence provides evidence of one type of evolution . 20 fossilized pterodactyls found in China in rock dating back 50 million years . They show creatures had one of two types of evolved pterodactyls . Scientists say fossils show groups of features changed relatively rapidly .