Bruhathkayosaurus (/bruːˌhæθkeɪoʊˈsɔːrəs/; meaning "huge-bodied lizard") is a controversial genus of sauropod dinosaur found in the Kallamedu Formation of India.

[4][5] The holotype of Bruhathkayosaurus, GSI PAL/SR/20, was discovered around 1978 near the southern tip of India, specifically in the Tiruchirappalli district of Tamil Nadu, northeast of Kallamedu village.

It was recovered from rocks of the Kallamedu Formation, which are dated to the Maastrichtian stage of the Late Cretaceous, about 70 million years ago.

[4] The generic name chosen, "Bruhathkayosaurus", is derived from a combination of the Sanskrit word Bruhathkaya (bṛhat बृहत्, 'huge, heavy' and kāya, काय 'body'), and the Greek sauros (lizard).

[6] The specific epithet, "matleyi", honours British palaeontologist Charles Alfred Matley, who discovered many fossils in India.

In 2017, Galton and Ayyasami reported that the Bruhathkayosaurus fossils started to disintegrate inside their field jackets before reaching the Geological Survey of India (GSI) and no longer exist.

This led to online speculation by researchers that the bones might actually have been petrified wood, akin to the way the original discoverers of Sauroposeidon initially believed their find to be fossilized tree trunks.

[11][12][13] A 2022 review by Pal and Ayyasami presented additional previously unseen photographs of the tibia bone at the excavation site and in a plaster jacket, and reinforced the taxon's position within Titanosauria.

[24] Another poorly known sauropod that shares similar size estimates to Bruhathkayosaurus is Maraapunisaurus fragillimus, which is based on a now-missing dorsal vertebra.

[3] Nevertheless, Paul stressed that the idea of these 'super-sauropods' or 'land-whales' aren't as far-fetched as one would think given the long period of sauropod existence as well as their very efficient body-plan (i.e. small heads, large body, efficient ventilated air-sacs, strong and flexible muscle and bone structure, and large source of static food), indicating that the existence of 150+ ton sauropods such as Bruhathkayosaurus and Maraapunisaurus are in the realm of possibility.