NEW DELHI — Scientists have discovered a fossilised upper jaw of an eleven million-year-old human ancestor in Kutch, Gujarat.

The find significantly extends the southern range of ancient apes in the Indian Peninsula, according to a study published in the journal PLOS ONE.

Apes, or hominoids, are a group of primates from Africa and Southeast Asia that includes the gibbons and the great apes: chimps, orangutans, gorillas, and humans.

Ancient ape remains from Miocene deposits in the Siwaliks of India and Pakistan have been key for understanding the evolution of great apes and humans.

Researchers from Birbal Sahni Institute of Palaeosciences in Lucknow, UP, examined an ape jaw fragment excavated from the Kutch basin, in the Gujarat state of western India, about 1,000 km south of the Siwaliks deposits.

X-ray computed-tomography revealed details of the preserved canine and cheek teeth, such as the tooth enamel and root structure.

The ape mandible belonged to an adult individual of the Sivapithecus genus, but the species could not be identified.

Researchers dated the specimen to the basal Late Miocene, around 11 to 10 million years ago based on previous mammalian fossil findings in the site.

The finding is the first Miocene ape fossil to be discovered so far south in the Indian peninsula, and extends the southern range of ancient apes in the subcontinent by about 1,000 km.