Dinosaur Footprints found in Thar desert

Q Why is it in News?

A In a major discovery, footprints of three species of dinosaurs have been found in the Thar desert in Rajasthan’s Jaisalmer district.

Q What are details of the footprints? 

A 

• The footprints, made in the sediment or silt of the seashore, later become permanently stone-like.
• They belong to three species of dinosaurs — Eubrontes cf. giganteus, Eubrontes glenrosensis and Grallator tenuis.
• While the giganteus and glenrosensis species have 35 cm footprints, the footprint of the third species was found to be 5.5 cm.
• The dinosaur species are considered to be of the theropod type, with the distinguishing features of hollow bones and feet with three digits.
• All three species, belonging to the early Jurassic period, were carnivorous.
• Eubrontes could have been 12 to 15 metres long and weighed between 500 kg and 700 kg, while the height of the Grallator is estimated to have been two metres, as much as a human, with a length of up to three metres.

Q What are the Key findings ? 

A 

• The discovery of dinosaur footprints prove the presence of the giant reptiles in the western part of the State, which formed the seashore to the Tethys Ocean during the Mesozoic era.
• Careful geological observations enabled the scientists to interpret ancient environments in which the rocks of the footprints, which were once soft sediments, were deposited.
• Geochemical analyses and calculation of weathering indices showed that the hinterland climate was seasonal to semi-arid during the deposition of the footprints.
• Fieldwork in the Kutch and Jaisalmer basins has suggested that after the main transgression during the early Jurassic period, the sea level changed several times.
• Spatial and temporal distribution of sediments and traces of fossils and post-depositional structures provided an indication to this phenomenon.

Q What is Significance of the finding ? 

A 

• These trace fossils are significant to ascertain how life started and evolved after the mass extinction of species, including dinosaurs, at the end of the cretaceous period around 65 million years ago.
• This research also illustrates the evidence of a fluvial freshwater palaeo-environment and tropical palaeo-climate, indicating the presence of a tropical forest and a huge network of rivers.