Puercosuchus (translated literally as "Puerco River crocodile") is an extinct genus of archosauromorph reptile from the Late Triassic (Norian) of what is now Arizona, North America.

Puercosuchus is known mainly from two bonebeds in the Blue Mesa Member of the Chinle Formation, preserving the mixed remains of multiple individuals in each one representing almost the entire skeleton.

However, Puercosuchus and its close relatives in the subclade Malerisaurinae retained the carnivorous diet and body form ancestral to archosauromorphs.

Unlike non-malerisaurine azendohsaurids, Puercosuchus had a long and shallow snout with sharp, blade-like teeth similar to those of carnivorous dinosaurs.

It was robustly built–albeit less bulky than Azendohsaurus or Shringasaurus–with deep shoulders, sprawling limbs and the characteristically long and raised neck of azendohsaurids.

Unlike other large azendohsaurids, its skull was more like those of earlier predatory archosauromorphs, with a proportionally longer and lower snout as well as recurved teeth with fine serrations.

Puercosuchus is known by almost its entire skeleton, but because its bones have only been found disarticulated and mixed together in bonebeds with few associated remains its overall limb and body proportions cannot be determined.

The surangular sports a raised triangular coronoid eminence just behind the dentary, which then tapers downwards through to the fused articular and to the jaw joint.

Both the basipterygoid processes (contacting the pterygoid bones beneath it) in front and the basal tubera at the rear project out and down from the parabasisphenoid on either side.

[1] The vertebral column of Puercosuchus is almost completely known, with vertebrae from every major section of the neck, back, hips and tail represented in the bonebeds.

The front and rear faces of the cervical centra, the main body of the vertebrae, are vertically offset from each other, a trait found in other azendohsaurids indicative of an elevated neck posture.

Similarly, the neural spines start off tall and subrectangular, projecting dorsally, but become longer and lower witraiseh rounded and expanded tips down the tail.

Both the cervical and trunk ribs are double headed (dichocephalous) with separate diapophyses and parapophyses on the vertebrae, unlike Malerisaurus robinsonae.

[1] The humerus is broadly similar to other azendohsaurids, with widely expanded ends and a prominent deltopectoral crest, although its shaft is more slender than those of Azendohsaurus or Shringasaurus.

[1] The scapula (shoulder blade) of Puercosuchus is similar to other azendohsaurids, being tall and relatively broad, although it is not constricted anywhere along its length unlike those of Azendohsaurus or Shringasaurus.

The interclavicle, a bone that connects each side of the shoulder girdle down the middle of the chest, is T-shaped with two sharply projecting lateral processes that articulate with the clavicles.

However, they had been incorrectly identified as the bones and teeth of various other disparate reptiles, including theropod, sauropodomorph and ornithischian dinosaurs, phytosaurs, "sphenosuchian" crocodylomorphs, and the related allokotosaur Trilophosaurus.

[8] Material from the Krzyzanowski Bonebed is found in association more often than at Dinosaur Wash, including parts of the jaws, limbs and backbones.

The generic name comes from the Puerco River, which runs through the Petrified Forest National Park and just to the North of the type locality.

[1] Both bonebeds are stratigraphically located within the Blue Mesa Member of the Chinle Formation, which has been radiometrically dated to between 221 to 218 million years old during the Norian stage of the Late Triassic.

[9] Dinosaur Wash more precisely correlates to the upper Blue Mesa Member, and so has been roughly estimated to be between 220–218 million years old.

[1][10] Puercosuchus is a member of Azendohsauridae, one of the major subclades of the unusual archosauromorph clade Allokotosauria that was established from the herbivorous and stockily built Azendohsaurus.

In their analysis, Puercosuchus was a derived member of Malerisaurine, which was the sister to a subclade including the herbivorous Shringasaurus and two species of Azendohsaurus.

[2] The cladogram below depicts the simplified consensus result of this analysis, where the uncertain relationships of Puercosuchus (as "Malerisaurus-like taxon PEFO") to other malerisaurines are presented as a polytomy: Kuehneosauridae Trilophosauridae Pamelaria Shringasaurus Azendohsaurus madagaskarensis Azendohsaurus laaroussii Malerisaurus robinsonae Malerisaurus langstoni Malerisaurus-like form large[a] Malerisaurus-like taxon PEFO[b] Based only on the holotype specimen PEFO 43914, Puercosuchus is diagnosed from other azendohsaurids by its procumbent first premaxillary tooth and its heterodont maxillary teeth—although the state of the former feature is unknown in both species of Malerisaurus and the latter unknown for M. langstoni.

However, additional diagnostic autapomorphies have been identified from the referred hypodigm, and include the keeled frontals, a quadrate with a hooked and pointed head and a foramen penetrating its body, the cultriform tooth, a foramen on the ventral ramus of the opisthotic, posterior caudal vertebrae with a high anterior process taller than their neural spines, a hooked anteromedial process of the ulna, a ridge on the inner surface of the distal, and a tubercle on the dorsal surface of the fifth metatarsal.

It remains unclear whether these aggregations are simply due to taphonomy or if it represents a genuine behavioural trait common to Puercosuchus and other azendohsaurids.

The distal third of its shaft is noticeably warped and twisted, artificially shortening the length of the femur, and its surface is scarred and shows excessive bone growth (hyperossification).

This includes coelacanths, hybodont sharks, lungfish, actinopterygian (ray-finned) fishes, a tanystropheid archosauromorph, the semi-aquatic archosauriform Vancleavea, the armoured aetosauriforms Acaenasuchus and a non-desmatosuchin aetosaur, a predatory paracrocodylomorph, and an indeterminate dinosauromorph.