India has turned out to be agold mine of clues - from an abundance of eggs to tell - tale dung - to the lives of dinos.
The discovery of an ancient dinosaur-eating snake species from a Gujarat village that made international headlines this past week was not a chance discovery. It was one more piece, a significant one at that, in the slowly unfolding jigsaw puzzle of India's fascinating fossil heritage.
Most Indians may not know that the geological history of Indian dinosaurs spans the Triassic, Jurassic and Cretaceous ages - spanning from about 230 million to 65 million years ago. In fact, some of the first fossils that were recognised as those of dinosaurs were found in India way back in 1828. The fossils - discovered by a British army officer William Sleeman, who was better known for wiping out the 'thuggee' menace, in Jabalpur - were described by the Scottish missionary Stephen Hislop in scientific literature in 1859. The species was later named Titanosaurus indicus.
Since that discovery, scientists with the Geological Survey of India ( GSI) have found remains of dinosaurs belonging to different ages of the "era of reptiles" which is believed to have come to an end some 65 million years ago. In popular psyche, dinosaurs are invariably connected with the Jurassic period - the middle age of the geological times - scale - made famous in sci- fi movies.
But the Triassic period extended from 250 to 200 million years ago, followed by Jurassic, which spanned from 145 to 200 million years. It was followed by the Cretaceous period extending from 145 to 65 million years ago. This is supposed to have been the golden age of dinosaurs, which came to an end with a massive asteroid hitting the planet. Indian dinosaurs are believed to have been wiped out by the Deccan volcanic eruption.
Though fossils found in India belong to all three ages, most of them are from the late Cretaceous period. Over the years, GSI scientists have found bones, skeletons, well- preserved eggs, egg shell debris, dung and other fossil fragments in western and central India, and even in the south. Fossilised footprints, or trackways, of the gargantuan creatures have not been found in any dinosaur- bearing sediments in India.
The earliest discovery of dinosaurs eggs were made from the Lameta sediments in the Kheda district of Gujarat in 1981.
Scientists were exploring the region for fossils in the area near Balasinor village, which had limestone quarries operated by the cement company, ACC. "A big boulder fell apart when the mine was blasted. I noticed that it contained seveneight spherical pieces. It was almost as if some eggs had been kept in a basket," recalls Dhananjay M. Mohabey, senior paleontologist with the GSI. "We did not know how dinosaur eggs looked like. This was the first time we were seeing something like this."
This discovery led to a resurgence of dinosaurs research in India, leading to a spate of finds belonging to the Late Cretaceous period in Gujarat, Madhya Pradesh, Maharashtra and Andhra Pradesh in the past three decades. A sole occurrence of a single egg has been recorded from the Ariyalur area in Tamil Nadu - the only record of an Indian dinosaur egg from marine sediments.
As many as 10,000 dinosaur eggs have been found at different nesting sites in Gujarat, Madhya Pradesh and Maharashtra.
Scientists believe that there could be up to 30,000 eggs at different locations. Most of these eggs belong to the titanosaurus. Eggs, nests and nesting sites provide an insight into the social and nesting behaviour of this class of dinosaurs.
These animals used to bury their eggs in soft sands near riverbanks and in a few rare nests, eggs have been found arranged in circular or linear patterns.
From dung found around Pisdura village near Nagpur, scientists have inferred what the herbivore dinosaurs used to eat. An analysis of this dung, in fact, revealed the remains of a grass family which turned out to be the oldest record of grasses found anywhere in the world.
"Evidence suggests that the environment during the Late Cretaceous period in India provided an ideal habitat for breeding and nesting of dinosaurs. But these reptiles were struggling to survive the initial onslaught caused by the Deccan volcanic eruption near the end of the Cretaceous period," explains Mohabey, who first found a complex set of fossils at Dholi Dungri village in Gujarat in 1987. It has now turned out to be that of an ancient snake along with fossils of crushed eggs and dino hatchlings. The Indian dinosaur eggs and plant- bearing dung are unique in the world for their diversity and abundance and offer promising material for future research on dinosaurs.
Most eggs found in India belong to the plant-eating sauropod dinosaurs, but the country was also home to carnivore dinosaurs as well. The most remarkable discovery of a carnivore is that of Rajasaurus narmadensis - a new species found at Rahioli village in the Narmada basin of Gujarat. The discovery represents the first skull ever assembled of a dinosaur of any kind in India.
Rajasaurus narmadensis - which means "regal dinosaur from the Narmada" - was a significant predator that was related to species on continental Africa, Madagascar and South America.
The discovery of this 65-millionyear-old was a joint effort of Suresh Srivastava of GSI, Ashok Sahni of Panjab University, Chandigarh, and Jeff Wilson of the University of Michigan, Ann Arbor ( USA). The stocky, 30-foot dinosaur had an unusual head crest and would have pursued a diet that included the long-necked sauropoddinosaurs that roamed the Narmadaregion. F INDING A dinosaur fossil, reconstructing the evidence and then presenting the find to scientific community is a long, torturous process that could sometimes take decades. Geologists look for dinosaur fossils in different rock sediments which have already been mapped. Systematic excavation of such areas is undertaken and when fossils are found the location is carefully mapped before the fossils are labeled and removed from there.
The rocks are scanned to see presence of bones. Then the rock sediments are removed through mechanical and chemical processes.
This prepares the fossils for reconstruction, body part by body part such as skull, jaw, limbs, pelvis, and so on. Fossils of associated including plants, flowers and animals are also studied in detail.
Only after this long process can anyone claim to have found a dinosaur fossil. Many a times false announcements are made. GSI scientists, for instance, clarify that the egg fossils reported last year from Tamil Nadu didn't belong to dinosaurs. The science of paleontology isn't as exciting as they make it out to be in the sci- fi movies.
The Union Cabinet is set to meet soon to decide if beleaguered state-owned carrier Air India should retain its 'national' character at all. It will also debate if strategic disinvestment is the best way forward for the airline, which is estimated to have accumulated Rs 7,200 crore in losses in 2009-10.
