In a paper printed not too long ago in Scientific Reports, scientists from IIT Roorkee have characterised dinosaur fossils from the Middle Jurassic interval, found in the Thar desert close to the Jaisalmer Basin by the Geological Survey of India. They found that they’d uncovered stays of a sauropod dinosaur, which is similar clade because the long-necked herbivores in Jurassic Park – solely these occurred to be the oldest recognized fossils of this explicit form of sauropod.
Belonging to the household Dicraeosauridae and from the superfamily Diplodocoidea, these fossils are the primary dicraeosaurid sauropods to have been found in India. And at 167 million years previous, they’re the oldest recognized diplodocoid fossils in the world. The scientists named the dinosaur Tharosaurus indicus, with Tharo deriving from the Thar desert; saurus from the Greek ‘sauros’, or lizard; and indicus from its Indian origin. The fossils had been found by Triparna Ghosh, Pragya Pandey, and Krishna Kumar from the Geological Survey of India.
167 million years previous
“The most fascinating feature about sauropods is their size,” mentioned Debajit Datta, a postdoctoral researcher in Sunil Bajpai’s group at IIT Roorkee and one of the lead authors of the paper. “They can grow more than a hundred feet. There are many sauropod groups that are even longer than the blue whale.”
However, members of the Dicraeosauridae household of sauropods – to which Tharasaurus belongs – weren’t almost as giant. This household was distinctive: its members had been smaller and had shorter necks and tails in comparison with the opposite long-necked sauropods.
Sauropods first appeared on the earth throughout the Jurassic interval, about 200 million years in the past. They had been one of essentially the most dominant clades of dinosaurs, surviving till the late Cretaceous interval 65 million years in the past, when the dinosaurs went extinct.
‘Somewhat of an enigma’
But unusually, in India, whereas sauropod fossils from the Early Jurassic and the Late Cretaceous interval have been found, only a few have from the Middle or Late Jurassic interval, which might be about 160-180 million years in the past.
“The Middle Jurassic remains somewhat of an enigma,” mentioned Advait Jukar, a palaeontologist on the University of Arizona. “Part of the reason is that we don’t have as many exposed rocks from this time period. We also haven’t put in a lot of effort into exploring these rocks in places where they are exposed, like in India.”
India has additionally been house to a few early, extra primitive sauropods, like Kotasaurus and Barapasaurus. They had been each found in the Kota Formation, a geological rock unit in Telangana, from the Early Jurassic interval. “We have extremely primitive sauropods, and now we have a dicraeosaur, which is more evolved,” Dr. Datta mentioned. “When we see this in conjunction with the arrangement of the continents in the Middle Jurassic, things start to get interesting.”
Importance of Indian landmass
Some 167 million years in the past when Tharosaurus lived, India was not the place it’s now; it was half of a group of continents in the southern hemisphere with Africa, South America, Madagascar, and Antarctica, collectively known as Gondwanaland. “Considering the fact that we already have more primitive sauropods in India and now the oldest diplodocoid, it is highly likely that India was the site of radiation of these diplodocoid dinosaurs to other parts of the world,” Dr. Datta mentioned.
The scientists reasoned that these diplodocoid sauropods may have originated in India throughout the Middle Jurassic interval and used the land connections on the time emigrate to Madagascar, Africa, and South America. After that they might have made their method to North America and the remaining of the world.
Another piece of proof that helps their principle was that diplodocoid fossils in different continents like Africa, the Americas, and Asia come from a youthful geological interval. This will increase the chance that the Indian landmass was the location for the Tharosaurus’ early radiation.
That together with the truth that archaic sauropod fossils from throughout the begin of the Jurassic interval – like of Kotasaurus and Barapasaurus – had been additionally found in India means that this diplodocoid group of sauropods may have developed and originated in India.
“This discovery of a new dinosaur from the Middle Jurassic in Rajasthan should not be seen in isolation; it must be looked at in conjunction with previously discovered dinosaurs in India,” Dr. Bajpai mentioned. “Together, the record from India suggests that the Indian landmass was one of the most important places for the early evolutionary history of sauropod dinosaurs.”
More fossils wanted
Dr. Bajpai cautioned, nonetheless, that this was solely the start. They didn’t discover the entire skeleton however components of the spine of the dinosaur. “A lot more needs to be discovered. Our science is such that with each new discovery, ideas change, and sometimes even identifications change.”
A palaeogeographic distribution of diplodocoids with taxa of completely different ages plotted collectively in a simplified Middle Jurassic (170 Ma) map to point out their spatio-temporal distribution throughout Pangea. Silhouettes point out the sort of diplodocoid and fossil occurrences. Numbers adjoining sauropod silhouettes point out age of the fossils as follows: 1—Middle Jurassic (early–center Bathonian); 2—Late Jurassic; 3—Cretaceous; 4—Middle Jurassic.
| Photo Credit:
Bajpai, S., Datta, D., Pandey, P. et al. Fossils of the oldest diplodocoid dinosaur recommend India was a main centre for neosauropod radiation. Sci Rep13, 12680 (2023).
“In the Middle Jurassic, when Tharosaurus lived, the continents were beginning to split apart from the supercontinent Pangea, and as these dinosaurs spread, they evolved into new forms,” mentioned Dr. Jukar. “A caveat here is that the fossil record of Middle Jurassic diplodocoids is comparatively poor, and that will heavily influence how we view their evolution and spread. For example, if we find one that’s even older than Tharosaurus in, say, Russia, we’ll have to re-evaluate our geographic hypotheses.”
Dr. Jukar is impressed with the discovering, however like Dr. Bajpai, believes that extra fossils should be found. More fossils of completely different components of the Tharosaurus skeleton or of different associated skeletons will assist us higher perceive endemic sauropod evolution in India and world sauropod evolution and biogeography.
“I think Tharosaurus is a remarkable find, but it is very fragmentary,” in keeping with Dr. Jukar. “It’s only once we have a better fossil record, not only geographically, but also in terms of fossil completeness, that we can start to get a clear picture of what sauropod evolution was doing during this crucial time in earth history.”
In 2006, an Indo-German crew found one other center Jurassic sauropod dinosaur fossil in the Kutch basin of Gujarat, named Camarasaurus supremus, which was additionally the oldest fossil of that group found on the time. There have been subsequent finds of extraordinarily previous sauropod fossils in the area by the identical crew since.
‘Extremely rare’
Dr. Bajpai mentioned that extra work and extra expeditions will should be undertaken in the Jaisalmer space. “This is a potentially important area for the Middle Jurassic dinosaurs in India.”
“Indian dinosaurs are extremely rare,” mentioned Dr. Jukar. “It’s not because they didn’t exist; it’s because we haven’t had the same level of palaeontological interest and investment that we’ve seen in other countries like the U.S., Canada, or China.”
Dr. Bajpai echoed this sentiment, emphasising the necessity for extra consideration on paleontological discoveries, particularly given the shortage of pure historical past museums. “We definitely need not one but many natural history museums … given the vast fossil wealth of our country.”
Rohini Subrahmanyam is a freelance journalist.
