| Diet | Carnivore |
| Height | Unknown |
| Length | Unknown |
| Environment | Land |
| Era | Cretaceous |
| Period | Late Cretaceous |
| Type | Theropod |
| Location | India |
Orthogoniosaurus is one of palaeontology's most mysterious theropod dinosaurs, known from a single fragmentary tooth discovered in the Late Cretaceous Lameta Formation of Jabalpur, India. The preserved section of this tooth measures just 2.7 centimetres long, making it one of the most incomplete dinosaur fossils ever described. This limited evidence has led scientists to classify it as a 'nomen dubium' - a scientific name that cannot be properly defined due to insufficient fossil material.
Living approximately 72.2 million years ago during the Late Cretaceous period, Orthogoniosaurus inhabited the ancient landscapes of what is now central India. The tooth's sharp, serrated structure suggests it belonged to a carnivorous theropod that likely hunted smaller prey, though without more complete remains, its exact size, appearance, and hunting behaviour remain complete mysteries.
The fragmentary nature of the only known Orthogoniosaurus specimen highlights both the challenges faced by palaeontologists and the incomplete nature of the fossil record. Many dinosaur species are known from similarly limited remains, representing tantalising glimpses of ancient life that may never be fully understood. Despite its uncertain status, Orthogoniosaurus remains an important part of India's rich Late Cretaceous fossil heritage.
The only known feature is a single tooth fragment with serrated edges typical of carnivorous theropods. The tooth's specific shape gave rise to its name meaning 'right-angled lizard', though the exact distinctive characteristics cannot be determined from such limited remains.
With only a single tooth fragment known, virtually nothing can be determined about Orthogoniosaurus's behaviour. The serrated tooth suggests it was a carnivore that likely used its teeth to slice through flesh, but all other behavioural aspects remain completely unknown.
Orthogoniosaurus was first described by Friedrich von Huene and Charles Alfred Matley in 1923. The original fossils were discovered at Lameta Formation, Jabalpur, India.
