Desmatosuchus (/dɛzmætoʊsuːkəs/, from Greek δεσμός desmos 'link' + σοῦχος soûkhos 'crocodile') is an extinct genus of archosaur belonging to the Order Aetosauria.

This archosaur's most distinguishing anatomical characteristics were its scapulae which possessed large acromion processes commonly referred to as "shoulder spikes".

[6] The pelvic girdle consisted of a long pubis with a strong symphysis in the middle, a plate-like ischium, a highly recurved ilium, and a deep, imperforate acetabulum.

[2] The dentary was about half the length of the lower jaw, with the front portion being toothless and covered by a horny sheath.

[8] Case later classified a partial skeleton found in the Tecovas Formation as Desmatosuchus spurensis.

[9] Since the localities of Cope and Case were only a few kilometers apart, the two taxa were synonymized into Desmatosuchus haplocerus, the initial type species of the genus.

[10] Desmatosuchus chamaensis is recognized as a distinct genus, but there is some dispute about whether the name Heliocanthus or Rioarribasuchus applies.

[8] The following cladogram is simplified, after an analysis presented by Julia B. Desojo, Martin D. Ezcurra and Edio E. Kischlat (2012).

[11] Aetosauroides scagliai Aetosaurus ferratus Coahomasuchus kahleorum Neoaetosauroides engaeus Calyptosuchus wellesi Stagonolepis robertsoni Aetobarbakinoides brasiliensis Typothorax Redondasuchus Tecovasuchus chatterjeei Rioarribasuchus chamaensis Paratypothorax andressorum Sierritasuchus macalpini Longosuchus meadei Lucasuchus hunti Acaenasuchus geoffreyi Desmatosuchus haplocerus Desmatosuchus smalli Bones and armor pieces of Desmatosuchus are abundant in the Dockum formation, Chinle formation, and Post quarry, indicating that they were widespread and abundant during the Late Triassic.

The low number of Desmatosuchus teeth that have been discovered indicates that they were only held in place by soft tissue connections.

[2] The herd nature of Desmatosuchus apparently did little to discourage predators, as Postosuchus along with several other Late Triassic carnivores also traveled in groups.

[13] Desmatosuchus possessed both of these features, along with its long femur and elongate pubis, making it more mobile than most thecodonts of its time.

[13] This mobility, along with its size, abundance, and specialized beak made it the chief herbivore in the Dockum area.

Also, there is evidence of bees, wasps, and termites in the Late Triassic, meaning that Desmatosuchus had access to insects that armadillos prey on.