A fortuitous rockfall in the Grand Canyon reveal the earliest fossil evidence of vertebrate footprint in the region , left by an testis - laying animal hundreds of million of years ago . The discovery , put out in the journalPLOS One , was made by a radical of hikers tramping the Grand Canyon National Park in 2016 .
When the bowlder in interrogation was released by the cliff near the canon ’s Bright Angel Trail , it exposed a stratigraphic crossing - section of the Manakacha Formation . The serendipitous serial of effect gave researcher a uncommon opportunity to glimpse into this ancient layer of tilt that was entrust to the ground around 313 million age ago .
Their investigations revealed two set of cracks that appear to have been set down by early four - limbed vertebrates , which judging by their narrow pace were either basal reptilian orsynapsids . From the drifting practice seen in the first set of footprints , it seems the animal was moving diagonally up a slope using a sidelong - succession pace that sees the legs on one side of the dead body move before the legs on the other side . The same type of walk is still seen in modern tetrapod such asdogs and cat .
The vertebrate footprint are the earliest object lesson ever observe in the Grand Canyon and reveal new information as to how early this way of motivity emerged in the evolutionary tree . It ’s undecipherable if the creature ’s gait was touch on by inclement weather or the steepness of the slope , but it shows that ancient craniate were living in the George Sand dunes 313 million years ago .
The second solidifying shows evidence of claw role , point this animal , which was likely the same species as the other set of footprints , made a beeline straight up the slope rather than making a docile , diagonal approaching . From the fossil evidence , it ’s impossible to say what species left the two sets of tracks , and the investigator state that they could well have been made by an animate being not yet known to science .
" These are by far the old vertebrate tracks in Grand Canyon , which is make love for its abundant fossil lead , " say palaeontologist and hint study author Stephen Rowland , from the University of Nevada Las Vegas , in astatement . " More significantly , they are among the Old tracks on Earth of shelled - egg - lay beast , such as reptiles , and the earliest evidence of vertebrate animals walk in Baroness Dudevant dunes . "
