AsianScientist (Jun. 23, 2020) – Paleontologists have discovered large well-preserved footprints near Sacheon City in South Korea, which they believe belonged to an ancient bipedal crocodile ancestor that lived around 120 million years ago.
The absence of hand impressions at the excavation site was baffling, given that modern-day crocodiles are four-legged. The footprints were therefore thought to have been made by giant flying reptiles called pterosaurs, walking on two legs to protect their wings when on land.
In a new study published in Scientific Reports, an international team led by Prof. Kim Kyung Soo of the Chinju National University of Education describe their discovery of nearly one hundred footprints during excavation at the Sacheon Jahye-ri site.
The tracks were made by a new species of crocodylomporh—ancestors to modern-day crocodiles, fish-eating crocodiles and alligators—which the authors have named Batrachopus grandis to indicate that the footprints were large.
“This is the first global report of large Batrachopus and the first to indicate bipedal progression. They form the basis of the new ichnotaxon Batrachopus grandis ichnosp. nov.,” the authors write.
The tracks are more than twice as large as previously found batrachopodid tracks and include footprint lengths of 18–24 cm, indicating a body length of up to three meters. The narrow trackways were made entirely by the back limbs, with clear heel to toe impressions and skin traces in some areas.
There is no definitive evidence, either from back footprints covering those made by the front feet or poor track conservation, to suggest the trackways were made by a four-legged crocodylomorph. This two-legged gait has not previously been seen from trackway specimens belonging to this family.
“The unexpected discovery of trackways so suggestive of bipedal locomotion by Cretaceous crocodylomorphs has ichnological implications bearing directly on long-standing and controversial debates about the gait of pterosaurs,” the authors write.
These new findings highlight the need for re-examination of morphologically similar specimens from this period in history, the authors say.
The article can be found at: Kim et al. (2020) Trackway Evidence for Large Bipedal Crocodylomorphs from the Cretaceous of Korea.
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Source: Nature; Photo: Anthony Romilio/University of Queensland.
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