The parietal of the frontal-parietal region is broad whereas the lower surface of the frontal is wide, the transverse crest lies above and behind the orbit. The frontals are concave and decline in to the front of the cranium. The supratemporal fossa is short and broad as in Antrodemus.[5] The incomplete skull is of unusual thickness, although it lacked a dome on frontal bones as seen in Majungasaurus. I would have also lacked the paired frontal horns seen in Carnotaurus. Both Indosuchus and Indosaurus had a conservative skull roof which was dorsoventrally thickened but did not process prominences above the skull roof, similar to the condition seen in Abelisaurus.[6]
The species I. matleyi weighed roughly 700 kg (1,500 lb).
Classification
Originally assigned by Huene to the Allosauridae, Indosaurus is today considered a member of the Abelisauridae family.[7] It shows similarities to the other Abelisaurids from India, such as Rajasaurus and Rahiolisaurus, and is hence usually placed within Abelisauridae, though the fragmentary nature for this taxon makes it difficult to recognize it's exact taxonomic validity.[8]
In 2014 Thierry Tortosa erected the subfamily Majungasaurinae. This was to separate Arcovenator, Majungasaurus, Indosaurus, Rahiolisaurus, and Rajasaurus from South American abelisaurids based on physical characteristics such as elongated antorbital fenestrae in front of the eye sockets, and a sagittal crest that widens into a triangular surface towards the front of the head.
It was suggested that the abelisaurids migrated between Africa, Europe, India and Madagascar, which would isolate the South American abelisaurids. It is possible that migration occurred between Europe and India across Africa given its proximity to both, and the volcanic Dras-Kohistan island arc may have allowed island hopping and an indirect path to Asia, though these are still questionable explanations.[9][10]
The following cladogram was recovered by Tortosa (2014):[9]
The rocks of the Lameta formation appear to have been deposited in fluvial or lacustrine conditions. The environment at the time of deposition has alternatively been considered semi-arid, or tropical humid.[11][12]
^F. von Huene and C. A. Matley, 1933, "The Cretaceous Saurischia and Ornithischia of the Central Provinces of India", Palaeontologica Indica (New Series), Memoirs of the Geological Survey of India21(1): 1-74
^ abTortosa, T.; Buffetaut, E.; Vialle, N.; Dutour, Y.; Turini, E.; Cheylan, G. (2014). "A new abelisaurid dinosaur from the Late Cretaceous of southern France: Palaeobiogeographical implications". Annales de Paléontologie. 100 (1): 63–86. Bibcode:2014AnPal.100...63T. doi:10.1016/j.annpal.2013.10.003.