Thoosuchus (meaning "active crocodile") is an extinct genus of basal trematosauroid trematosaurian temnospondyl.

[1][2][3] The benthosuchids were originally composed of the majority of basal trematosaurian forms regarded as the ancestors of the trematosaurids.

[10] Thoosuchus superficially resembles the more derived trematosaurids, but can be distinguished from them on the basis of a deep, narrowing otic notch.

[11][12] It had widely spaced orbits and a moderately elongated skull roof that was well ornamented with ridges and grooves, especially on the parietals.

Thoosuchus in a cladogram after Novikov (2018) with only Early Triassic Eastern Europe taxa included:[16] Luzocephalus Samarabatrachus Poryolosuchus Parotosuchus Selenocara Wetlugasaurus Vladlenosaurus Qantas Prothoosuchus Thoosuchus Trematotegmen Angusaurus Inflectosaurus Trematosaurus Syrtosuchus Benthosuchus Vyborosaurus Yarengia