size, two additional regression equations were used, one based on the length of the femur and the other based on skull length. The former yielded a maximum length of only , considered to be an underestimate, while the latter resulted in a maximum length of over . The estimate is favored by Datta and Ray, who argue that it is most in line with the body size seen in other derived phytosaurs including Smilosuchus. This would consequently mean that Colossosuchus was among the largest known phytosaurs discovered. These estimates, however, only apply to the largest known individuals and do not represent the average size attained by Colossosuchus. The fact that the fossils were discovered in a mass death site instead provides a wide range of sizes for the 21 known invididuals, which range from juveniles to fullly mature adults. Skeletally immature members of this species are generally smaller than and characterized by their comparably big eyes, lacking ornamentation, unfused bones and poorly developed muscle scars. Subadults and transitionals individuals are thought to occupy a size range between while skeletal maturity appears to have been reached at a length greater than . Phylogeny The phylogenetic analysis conducted for Colossosuchus was based on a 2021 dataset by author Debajit Data, which included 24 different taxa compossed of 23 phytosaurs and Euparkeria as the outgroup. The analysis was built around a total of 106 anatomical characters, most of which regarded the skull, including 11 traits not previously included in analysis. Besides Colossosuchus, two undescribed phytosaur skulls from India were also included (ISIR271 & (ISIR276). The strict concensus tree yielded from the analysis was only poorly resolved and features multiple polytomys, yet also displays some much clearer separations. Specifically, members of the Mystriosuchinae are clearly set apart from non-mystriosuchine phytosaurs and within the subfamily, the leptosuchomorphs likewise form a distinct cluster of species. Colossosuchus was found to be a mystriosuchine, forming a distinct clade together with the two undescribed skulls that were included. This grouping sits alongside Volcanosuchus, Rutiodon and the clade formed by Angistorhinus and Brachysuchus at the base of Mystriosuchinae, which further diverges into the also poorly resolved Leptosuchomorpha. Although the information provided by the strict concensus is limited, clearer results were yielded by the tree resulting from the 50% majority rule. This tree agrees with the broader ideas present in the strict concensus, but clears up several of the polytomys present