It is known from two species; S. imperator from the early Albian Elrhaz Formation of Niger, and S. hartti from the Late Hauterivian of northeastern Brazil.

In 1964, an almost complete skull was found in Niger by the French CEA, but it was not until 1997 and 2000 that most of its anatomy became known to science, when an expedition led by the American paleontologist Paul Sereno discovered six new specimens, including one with about half the skeleton intact and most of the spine.

The osteoderms, also known as dermal scutes, of Sarcosuchus were similar to those goniopholodids like Sunosuchus and Goniopholis; they formed an uninterrupted surface that started in the posterior part of the neck down to the middle of the tail as is seen in Araripesuchus and other basal crocodyliforms; this differs from the pattern seen in living crocodiles, which presents discontinuity between the osteoderms of the neck and body.

However, extrapolation from the femur of a subadult individual as well as measurements of the skull width further showed that the largest S. imperator was significantly smaller than was estimated by Sereno et al. (2001) based on modern crocodilians.

[13] Pholidosaurus Terminonaris Sarcosuchus During the course of several expeditions on the Sahara from 1946 to 1959 which were led by the French paleontologist Albert-Félix de Lapparent, several fossils of a crocodyliform of large size were unearthed in the region known as the Continental Intercalaire Formation.

The study of this material by French paleontologist France De Broin helped identify them as coming from a long-snouted crocodile.

[16] Now residing in the British Museum of Natural History, the fragment of the lower jaw, dorsal scute and two teeth compromising the species G. hartti were reexamined and conclusively placed in the genus Sarcosuchus.

[4] The next major findings occurred during the expeditions led by the American paleontologist Paul Sereno in 1995 (Aoufous Formation, Morocco), 1997 and the follow-up trip in 2000.

[18] Indeterminate Sarcosuchus material including dorsal osteoderms in anatomical connection, isolated teeth and fragmentary skeletal remains including a left scapula, mandible fragment, dorsal vertebrae, ilium and a proximal portion of a femur was described from the Oum Ed Dhiab Member in Tunisia in 2018.

[3] Approximately 40 lines of arrested growth (LAG) were counted in these thin sections, suggesting that S. imperator took 50 to 60 years to reach adult size.

[3] Given that extant wild crocodylians rarely reach these advanced ages,[5][20] Sereno suggested that S. imperator achieved its large size by extending its period of rapid, juvenile, growth.

[9] Based on the broader snout of fully grown S. imperator when compared with the living gharial and other narrow-snouted crocodiles, along with a lack of interlocking of the smooth and sturdy-crowned teeth when the jaws were closed, Sereno et al.[3] hypothesized that S. imperator had a generalized diet similar to that of the Nile crocodile, which would have included large terrestrial prey such as the abundant dinosaurs that lived in the same region.

[3] However, a 2014 analysis of a biomechanical model of its skull suggested that unlike Deinosuchus, Sarcosuchus may not have been able to perform the "death roll" maneuver used by extant crocodilians to dismember their prey.

[3] The stratigraphy of the region and the aquatic fauna that was found therein indicates that it was an inland fluvial environment, entirely freshwater in nature with a humid tropical climate.