For the first time, Indian paleontologists unearthed hominoid monkey fossils from the localities of Gujarat.
The researchers consider the finding important because it is the first proof of the presence of monkeys outside the Himalayas. "These locations are globally rare and each new location brings a lot of excitement," says Ansuya Bhandari, a paleontologist at the Birbal Sahni Institute in Palaeosciences in Lucknow who found the fossil and led the study.
"This discovery is very important. [as it indicates] similar ecological conditions 11 million years ago in Kutch and the Himalayan region ", V.P. Mishra, a former deputy director general of the Geological Society of India, told The Wire. He was not involved in the study.
The researchers were able to date the fossil 10.8 million years ago (mya) – from the Miocene era.
This geological period lasted between 23 and 5 mya. He created many hominoid remains that contributed to our understanding of human evolution since the first such fossil was found on the Potra plateau in Pakistan in 1879. In the last 140 years, Miocene-era hominoids have been found over the Siwalik foothills of the Himalayas only in Pakistan, India and Nepal, "according to Bhandari.
This means that this discovery is a potential game changer. "Now we know that Sivapithecus"- the ancestor of modern monkeys, who resembled an orangutan and lived in the Miocene between 12.5 and 8.5 mya -" had a fairly extensive range, from Kutch in the south and west to Nepal in the north and east, "says David R. Started, an anthropologist at the University of Toronto, Canada. "It must have been a kind of success to be found in many places around 10 million years ago."
In other words, paleontologists can find more fossils from this region. If they do, they will be able to construct a clearer picture of how these ancestors of the great apes could have migrated to the southern Himalayas.
"This discovery of Kutch would greatly help in understanding the connection of the Himalayan fauna with that of the Indian peninsula," according to Bhandari.
In India, most of the hominoid fossils were found in the Hari Talyanagar and Ramnagar basins in Jammu and Kashmir. The Ramnagar fossils were dated around 12.7 mya and the Hari Talyanagar fossils, between 9.2 and 8.6 mya.
The Miocene Hominids are divided into two groups: the largest Indopithecus and the smallest Sivapithecus. The only species in the first group, Indopithecus giganteus, was reported in Hari Talyanagar in 1969. Three species of Sivapithecus – S. indicus, S. flock and S. sivalensis – were found in the Pakistani and Indian mountains of Siwalik.
"We did not expect to find hominid here (Kutch)," says Sunil Bajpai, head of the Earth Sciences Department at IIT Roorkee and was part of the study.
But Bhandari and Bajpai were hopeful. In the winter of 2011, they were in Kutch looking for fossils. The area has created many fossils in the past, including whales, crocodiles, sawfish, turtles and other sea creatures. A few years earlier, they found remains of giraffes, rhinos and animals that resemble today's elephants and wild boars. These discoveries allowed them to suppose that these creatures had migrated from Africa and Europe at the time of the supercontinent of Gondwana.
To join the geological timeline of these events, the team began looking for the fossil remains of rodents, who are among the first animals to colonize a region.
At the end of that field trip, a rocky clearing with some patterns caught the attention of Bhandari. Some digging and cleaning around the pattern revealed a jaw – the first indication that hominids were traveling south to the Himalayas.
The researchers found that the fossil was the upper right mandible of an adult hominoid. It includes parts of the thickened ridge that contains tooth inserts that connect to the face bone and the ridge of the mouth.
Canine and molar teeth were also identifiable. A CT scan reveals that although the enamel capsules have been damaged, it was possible to estimate the dimensions of the teeth.
The proportions of the canine and the premolars were more similar Sivapithecus than Indopithecus. Specifically, the first and second molars were round with little developed crest, as in other Sivapithecus and monkeys from the Miocene.
Although this feature was increasing, the team wanted to make sure they were on the right track. Then they took the help of a horse.
In 2011, the team found remains of a Hipparion for the first time. O Hipparion is the ancestor of the modern horse and originated in North America. According to Bhandari, its presence is a "biological marker" because it spread through Gondwanaland between 2 and 22 mya. The mandible and the Hipparion fossils were both dated to about 11 mya. Indopithecus 9 mya appeared for the first time. Thus, the mandible probably belonged to a Sivapithecus monkey.
The Miocene period, between 15 and 7 mya, had a hot and humid climate with evergreen and deciduous forests covering large parts of the northern Indian subcontinent. These forests gave way to savannahs with arid and open habitats. The species that inhabited these forests either moved south or perished.
"I just want to show that there was connectivity of the Himalayan fauna to the Kutch region," says Bhandari, probably due to similar habitable conditions. "But we need more fossils from the region to piece together the puzzle."
The study was published in the journal PLoS ONE on November 14, 2018.
Vrushal Pendharkar is a freelance science writer.