Prestosuchidae was a polyphyletic grouping of carnivorous archosaurs that lived during the Triassic. They were large active terrestrial apex predators, ranging from around in length. They succeeded the Erythrosuchidae as the largest archosaurs of their time. While resembling erythrosuchids in size and some features of the skull and skeleton, they were more advanced in their erect posture and crocodile-like ankle, indicating more efficient gait. "Prestosuchids" flourished throughout the whole of the middle, and the early part of the late Triassic, and fossils are so far known from Europe, India, Africa, Argentina, and Paleorrota in Brazil. However, for a long time experts disagree regarding the phylogenetic relationships of the group, what genera should be included, and whether indeed the "Prestosuchidae" constitute a distinct family. In 2011, Prestosuchidae in its broadest definition was determined to be a poorly-diagnosed and obsolete polyphyletic group of pseudosuchians leading to the more "advanced" rauisuchids and crocodylomorphs. Some studies since then have reintroduced the term Prestosuchidae in a more limited setting. In these studies it refers to a cladecontainingPrestosuchus, Saurosuchus, and Luperosuchus. Even so, the validity of this clade is unclear, and it is often not supported over a paraphyletic arrangement of its constituents.
Classification
In 1957, Alan Charig proposed a new family, the Prestosuchidae, to include genera like Mandasuchus, Prestosuchus, and Spondylosoma. In 1967, Alfred Sherwood Romer placed Saurosuchus and Rauisuchus within Erythrosuchidae and adopted the Prestosuchidae to include Prestosuchus, Procerosuchus, and Mandasuchus. Prestosuchidae have often been included within Rauisuchidae, although they have sometimes considered the sister group of the aetosaurs in a monophyletic Pseudosuchia, or as a small clade intermediate between basal Crurotarsi and more advanced archosaurs such as the Aetosauridae and Rauisuchidae. J. Michael Parrish's 1993cladistic analysis of crocodylotarsan archosaurs places the Prestosuchidae outside the crocodylomorph - poposaurid - rauisuchid - aetosaur clade. In most cladograms, Prestosuchids are considered more derived than phytosaurs and ornithosuchids, but usually less derived than the poposaurids and aetosaurs. A 2011 study of archosaurs by Sterling Nesbitt found that prestosuchidae is a polyphyletic group of various unrelated suchians. For example, Ticinosuchus was found to be the sister taxon to paracrocodylomorpha while Prestosuchus and Saurosuchus were basal loricatans. The study determined that many of the characteristics previously used to define prestosuchidae were present in a wide variety of pseudosuchians. Although Parrish used many traits of the ankle to characterize prestosuchids, Nesbitt showed that these traits were present in various basal suchian groups. In 2004, Benton proposed another trait to define Prestosuchidae: a narrow, triangular antorbital fenestra. However, Nesbitt found this trait in Postosuchus, Dromicosuchus, and Fasolasuchus.
Evolution of the group
The earliest known "prestosuchid" is Mandasuchus from the Anisian of Tanzania. This was already a large animal, about 4.75 meters long. A similar but smaller form is Ticinosuchus of the Middle Triassic of Switzerland and Northern Italy, which was about 2.5 meters in length. The huge Batrachotomus from the latest Middle Triassic of Germany, and Prestosuchus of the early Late Triassic of Brazil may have been closely related animals. Yarasuchus, a lightly built archosaur from the Middle Triassic of India, was once assigned to this group, although a 2017 study placed it as an avemetatarsalian in the newly defined group Aphanosauria. Finally, Saurosuchus was a huge carnivore, 6 or 7 meters long, whose fossils are known from the Late Carnian of Argentina.
