heavy , well - preserved footprints institute in a fossil - deep area of South Korea likely belonged to a two - legged ancestor of modern - day crocodiles that boom 100 - 145 million years ago , and not giant pterosaur as previously thought , according to new research publish inScientific Reports .
The Lower Cretaceous Jinju Formation in South Korea is afossil - richoutcrop assess 800 square meters with up to 5 measure of stratigraphic division . Multiple set of footprints are abundant at all levels of the outcrop and were antecedently thought to have been made by elephantine pterosaurs walk on two legs . However , palaeontologists at the Chinju National University of Education and the University of Queensland , Brisbane argue that they were in all likelihood left by two - legged harbinger of what we know today as crocodile .
" Surprisingly , the coherent absence of manus [ hand ] tracks in the trackways , with well - preserve digitalpad and skin traces , argues for bipedal trackmakers , " the authorswrite . " No definitive evidence , either from pes - on - manus [ foot on script ] overprinting or poor track preservation , suggests the trackways were made by quadrupeds that only appear biped . "
At the meter of their uncovering , the tracks were namedBatrachopus grandisand value about double as long as they are wide-cut – between 18 and 24 cm ( 7 and 9.5 inches ) , which indicates a body length of up to 3 meters ( roughly 10 feet ) .
researcher remove large casts of the raw impression and documented them with photos and three - dimensional photogrammetry , tracing the trail limn and measuring their parameters .
A thorough analysis conclude that the tracks belong to a newfangled specie of crocodylomorph , an former mathematical group of reptiles that are ancestors to modern - day crocodile , Pisces - eating crocodiles , and alligators that were more mundanely adapted than other species at the time . TheB. grandistracks are the first to betoken bipedal , or two - legged , forward motion – a antecedently strange characteristic for this family . The findings could mean that tracks found at young website may belong to crocodylomorphs , which were antecedently think to have been left by jumbo pterosaur that walked on two legs to protect their offstage when on commonwealth .
“ The discovery ofB. grandiswas made soon after the discovery and verbal description of Korean Crocodylopodus and significantly enhances our understanding of the sound structure , size range , abundance and saving factors dissemble Korean crocodylomorph tracks , ” write the authors , adding that the findings call for a re - exam of other specimen that were morphologically similar at this time period .
