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]
References
^Bonaparte, J. F. 1981. Description de "Fasolasuchus tenax" y su significado en la sistemarica y evolucion de los thecodontia. Revista del Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"3:55–101.
^Bonaparte, J. F. (1986). Locomotion in Rauisuchid Thecodonts. Journal of Vertebrate Paleontology3(4):210-218.
^Nesbitt, S. J., Brusatte, S. L., Desojo, J. B., Liparini, A., França, M. A. G. D., Weinbaum, J. C., & Gower, D. J. (2013). Rauisuchia. Geological Society, London, Special Publications, 379(1), 241–274.
https://doi.org/10.1144/SP379.1
^Sulej, T. (2005). A new rauisuchian reptile (Diapsida: Archosauria) from the Late Triassic of Poland. Journal of Vertebrate Paleontology25(1):78–86.
^Weinbaum, J. C. and Hungerbüler, A. (2007). A revision of Poposaurus gracilis (Archosauria: Suchia) based on two new specimens from the Late Triassic of the southwestern U.S.A. Paläontologische Zeitschrift81(2):131-145.
^Apesteguia, S. (2005). Evolution of the hyposphene-hypantrum complex within Sauropoda. In: Virginia Tidwell, Kenneth Carpenter, eds., Thunder-lizards: the Sauropodomorph dinosaurs. Bloomington. Indiana University Press. pp. 248-267.