It once inhabited the slow-moving rivers, estuaries and lagoons of what is now Gebel Zelten and Wadi Moghra, environments it shared with a variety of other crocodilians including the narrow-snouted Euthecodon and the robust Rimasuchus.

[2] While multiple studies went on to use this much more complete specimen as a stand in for the holotype of T. dowsoni in phylogenetic analyses its specific referral was never questioned throughout most its history, even with it being generally accepted that this species did not directly clade with the modern false gharial of the genus Tomistoma.

[3] In the year 2000, Christopher Brochu and Philip D. Gingerich published a paper that argued that all tomistomines of the Miocene Mediterranean represented a single taxon, Tomistoma lusitanica.

[4] Llinás Agrasar followed this conclusion when describing fossils (MNHN LBE 300–302) from the Maradah Formation at Gebel Zelten, Libya, in 2004, but did note that the animal closely resembled the specimens previously known as Tomistoma dowsoni.

In accordance with phylogenetic analyses consistently recovering T. dowsoni as only distantly related to the modern false gharial, a new generic name was coined for and assigned to the material: Sutekhsuchus.

The widest point of the rostrum occurs around the level of the second premaxillary tooth in the Hamilton skull and the fourth in the syntype before the snout rapidly constricts just behind the premaxillae.

[3] Unlike in many contemporary forms such as Gavialosuchus and Tomistoma lusitanica, the maxillae do not extend between the nasals and the lacrimals, instead resembling what is seen in the modern false gharial.

[3] The frontal bone serves as a bridge between the rostrum and the skull table and, like in derived gavialoids, extends beyond the front-most tip of the prefrontals, forming a long anterior process.

Conversely, several early diverging gavialoids, the modern false gharial included, feature an indentation in the skull table where these more derived forms preserve the supraoccipital.

Sutekhsuchus is among a select number of gavialoids in which the palatal surface of the upper jaw is located below the toothrow, meaning that the roof of the mouth is well visible even in profile view.

[7] This study further recovered tomistomines and gavialines as entirely separate branches of Crocodilia, something no longer supported by either molecular or morphological evidence.

[3] In 2021 Jonathan Rio and Phillip Mannion managed to recover tomistomines and gavialines in a single unified Gavialidae using only morphological evidence.

[3] Rodolfo Salas-Gismondi and colleagues corroborated the placement of this taxon as a derived gavialid more closely related to Gavialis than Tomistoma, though their results differ in other areas (such as the absence of thoracosaurs and the presence of a monophyletic Gryposuchinae).

Under equal weighting, the modern false gharial clades with gavialoids from the Eocene of Northern Africa and Europe, forming a monophyletic group outside of Gavialinae that does not include many of the species once assigned to it (most of which instead were found to be relatives of Gavialosuchus and Thecachampsa).

For example, the modern false gharial stands on its own with no close relatives as the basal-most offshoot of Gavialinae, after which the East Asian clade splits off from the subfamily followed by the taxa clustering around Gavialosuchus and Thecachampsa, the opposite order of what is seen under equal weighting.

Nonetheless, both localities share much of their fauna (up to two thirds of the present mammalian taxa) and are typically thought to have been similar environments during the time fossils were deposited there.

Based on these findings and the geology of the area, it has been proposed that the environment preserved in these localities consisted of slow moving rivers that emptied into the Tethys sea, estuaries and lagoons, likely surrounded by forest.

Small depressions in the internal surface of the prefrontal and lacrimal left by the endocast have been interpreted to represent salt glands, allowing for the animal to easily venture into marine biomes.