Notosuchus was relatively small, reaching 1.5 m (5 ft) in length and a weight of 36 kg. Remains have been found in the Bajo de la Carpa Formation in Patagonia, Argentina. First named in 1896, Notosuchus was the first known notosuchian. The type species is N. terrestris. A second species, N. lepidus, was named in 1957.
A paper published in 2008 by Fiorelli and Calvo described new remains of the type species N. terrestris. In it, the authors suggested that the skull would have supported a short trunk, or "hog's snout" as well as fleshy upper and lower lips. The anteriorly directed nares and the absence of a bony nasal septum (which presumably indicates cartilaginous tissue serving its place) provide evidence for a trunk-like snout, while striations on the surface of the nasal bones and the lower jaw most likely acted as attachment points for the nasolabial muscles and the depressor muscle, respectively. Additionally, the authors suggested that a lateral rim on the dentary as well as numerous aligned neurovascular foramina are evidence of soft cheek-like muscular tissue. The function of the trunk was likely used for searching for food by sniffing the ground in a manner similar to extant suids and peccaries, while the cheeks would aid in mastication by preventing food loss.