Diagram showing preserved portions of the skull compared to a human
Fasolasuchus is likely the largest known "rauisuchian", with an estimated length of 8 m (26 ft)[3] to 10 m (33 ft).[4][5]
This would make Fasolasuchus the largest terrestrial predator to have ever existed save for large theropods, surpassing the Cenozoic Barinasuchus, the rauisuchian counterpart Saurosuchus at 7 metres (23 ft), and many medium sized theropods as large as Ceratosaurus.[6][7][8] Like Saurosuchus, it had only a single row of caudal osteoderms, unusual among rauisuchians.[9] It also had a hyposphene-hypantrum articulation that gave the vertebral column extra rigidity. This feature is also seen in several other rauisuchians such as Postosuchus as well as saurischiandinosaurs.[10][11]
A study on bone microstructure determined that Fasolasuchus had a relatively fast growth rate, similar to most other rauisuchians, with the exception of Prestosuchus. The same study also determined that the specimen was somatically and skeletally mature, but it wasn't possible to determine sexual maturity: this may be due to taphonomic causes, however the bone cortex was mostly preserved and didn't show the changes in bone matrix or in vascularization that would be expected if the specimen was sexually mature. Alternatively, Fasolasuchus attained sexual maturity contemporaneously to or slightly later than somatic and skeletal maturity (although this growth pattern is today only found in birds, not crocodilians), or there were differences in the timing of maturity of different bones in the same individual, as reported in the tuatara and in some dinosaurs.[7]
