[1] The teeth of S. clarki were shaped like maple leaves, which coupled with its short and deep snout suggests it was not a carnivore like most other crocodylomorphs.

Most remains of Simosuchus were found as part of the Mahajanga Basin Project, directed by the Université d'Antananarivo and Stony Brook University.

Material was usually found in clays that were part of flow deposits in the Anembalemba Member of the Maevarano Formation.

The snout resembles that of a pug, giving the genus its name, which means "pug-nosed crocodile" in Greek.

The glenohumeral condyle of the humerus, which connects to the pectoral girdle in the shoulder joint, has a distinctive rounded ellipsoid shape.

[8] Notosuchus Anatosuchus Comahuesuchus Malawisuchus Uruguaysuchus Simosuchus Sebecosuchia Uruguaysuchidae Peirosauridae Candidodon Libycosuchus Simosuchus Malawisuchus Notosuchus Comahuesuchus Mariliasuchus Chimaerasuchus Sphagesaurus Sebecosuchia Simosuchus was first considered to be a basal member of the clade Notosuchia, and was often considered to be closely related to Uruguaysuchus from the Late Cretaceous of Uruguay and Malawisuchus from the Early Cretaceous of Malawi.

Later phylogenetic studies have placed it closer to the genus Libycosuchus and in a more derived position than some other notosuchians such as Uruguaysuchus.

Uruguaysuchus, previously considered to be a basal notosuchian and a close relative of Simosuchus, was placed in its own family, Uruguaysuchidae, also outside Notosuchia.

[12] The following cladogram simplified after a comprehensive analysis of notosuchians which focused on Simosuchus clarki presented by Alan H. Turner and Joseph J. W. Sertich in 2010.

[3] The osteoderm shield was inflexible, restricting lateral movement in Simosuchus as a possible adaptation to an entirely terrestrial lifestyle.

[7] A fossorial, or burrowing, lifestyle for Simosuchus has been suggested in its initial description based on the robust limbs and short snout, which appears shovel-like, and the underslung lower jaw that would prevent friction when the animal opens its jaws during burrowing.

They also pointed out that the snout is not shovel-like, since it doesn't have a "dorsoventrally narrowed cutting edge" on it, but rather has a "relatively expansive anterior surface" which is almost completely flat.

The upper jaw was also suggested to be not adapted for keeping its mouth shut when faced by reaction forces associated with burrowing.

They also suggested that its relatively short neck would have been a potential advantage for moving through a dense medium like a tunnel, and that it may have likely used its head on occasions to aid scratch-digging with its limbs.

[17] Nearly all notosuchians are known from Gondwana, the southern supercontinent that existed throughout much of the Mesozoic and encompassed South America, Africa, India, Australia, and Antarctica.

Unresolved relationships among notosuchians along with an incomplete fossil record have made it difficult to determine the biogeographic origins of Simosuchus.