Suchomimus is a genus of large theropod dinosaur that lived in what is now Niger during the Albian to Aptian stages of the Early Cretaceous period, 112 million years ago. The only known species is S. tenerensis, originally described in 1998 by paleontologist Paul Sereno and colleagues from several fossils discovered one year earlier in the Elrhaz Formation. Although these fossils come from multiple specimens, they represent one of the most anatomically well-documented spinosaurids. The animal's generic name, which means "crocodile mimic", alludes to its elongated skull and piscivorous adaptations, while the specific name refers to the Ténéré Desert, where the fossils were discovered.

With an estimated length of 9.5–11 metres (31–36 ft) and a body mass ranging from 2.5–3.8 metric tons (2.8–4.2 short tons), Suchomimus was a particularly large theropod. As its generic name suggests, the animal’s skull was elongated, low, and narrow, resembling that of crocodilians. The tip of the snout flared laterally to form a rosette, and the jaws bore numerous finely serrated conical teeth, with the largest ones positioned near the front. The neck of Suchomimus was relatively short, while its powerfully built forelimbs bore a large, curved claw on each thumb. Along the midline of the animal's back ran a low dorsal sail, built from the long neural spines of its vertebrae. Its cranial and limb features indicate that it was a primarily piscivorous predator adapted for hunting in shallow waters.

Many paleontologists consider Suchomimus to be a probable junior synonym of the contemporaneous spinosaurid Cristatusaurus, although the latter taxon is based on much more fragmentary remains. Some researchers have also suggested that Suchomimus might represent an African species of the European spinosaurid Baryonyx, and it has occasionally been referred to in the scientific literature as B. tenerensis. However, more recent studies continue to regard the two genera as distinct. According to the fossil record of the Elrhaz Formation, Suchomimus lived and hunted in a fluvial environment of vast floodplains alongside many other dinosaurs, in addition to pterosaurs, crocodylomorphs, bony fishes, turtles, and bivalves.

In late 1997, American paleontologist Paul Sereno and his team conducted an expedition at the Gadoufaoua site in the Ténéré Desert of Niger, where they uncovered various fossils. On 4 December, team member David Varricchio discovered a large thumb claw belonging to a massive theropod dinosaur, remarkably well exposed on the surface. According to Sereno, the sand and wind had gradually revealed this claw, which had remained visible in this state for at least two centuries. Subsequent excavations at the site recovered several fossils from different individuals of this enigmatic theropod, which proved to belong to the spinosaurid family. On 13 November 1998, the Science Magazine published a study led by Sereno, formally naming and describing the new genus and species Suchomimus tenerensis based on the fossils discovered during the expedition. The generic name Suchomimus derives from the Ancient Greek σοῦχος (souchos, "crocodile"), and μῖμος (mimos, "mimic") literally meaning "crocodile mimic", in reference to its elongated snout and piscivorous adaptations. The specific name tenerensis refers to the desert where the animal’s fossils were found.

All known fossil specimens were recovered from the Tegama Beds of the Elrhaz Formation and are now housed in the paleontological collections of the Musée National Boubou Hama in Niamey. The holotype, catalogued as MNN GDF500, consists of a partial skeleton lacking the skull. It contains three neck ribs, parts of fourteen dorsal (back) vertebrae, ten dorsal ribs, gastralia (or "belly ribs"), pieces of three sacral vertebrae, parts of twelve caudal (tail) vertebrae, chevrons (bones that form the underside of the tail), a scapula (shoulder blade), a coracoid, a partial forelimb, most of the pelvis (hip bone), and parts of a hindlimb. Other notable specimens are also mentioned in the paper describing the taxon. Specimens MNN GDF 501 to 508 include a snout, a quadrate from the back of the skull, three dentaries (tooth-bearing bones of the lower jaw), an axis (second neck vertebra), a rear cervical vertebra, and a rear dorsal vertebra. Specimens MNN GDF510 and 511 consist of two caudal vertebrae. In the same article, Sereno and colleagues also reported additional bones and teeth attributed to this dinosaur, though their catalogue numbers were not specified. Although Suchomimus is among the best-known spinosaurids anatomically, its original description remains relatively brief.

More than two months before S. tenerensis was formally described in the scientific literature, French paleontologist Philippe Taquet and his Canadian colleague Dale A. Russell named another spinosaurid from the Elrhaz Formation, Cristatusaurus lapparenti, based on fragments of jaws and vertebrae. The fossils of this taxon were first discovered in 1973 by Taquet at Gadoufaoua, who later reported the find and described the fossil premaxillae in a paper published in 1984. Although he did not assign them a scientific name at the time, the author recognized the fossils as belonging to a large theropod of the Spinosauridae family based on anatomical features shared with the now-destroyed holotype of Spinosaurus aegyptiacus. In a 1986 publication, British paleontologists Alan Charig and Angela Milner noted that the jaw elements described by Taquet were nearly indistinguishable from those of the spinosaurid Baryonyx walkeri, which they had just described from a partial skeleton dating to the Barremian stage of the Weald Clay Formation in England. In a 1997 follow-up to their preliminary paper, the same authors referred Taquet’s fossils to an indeterminate species of Baryonyx, despite their younger geological age. In their 1998 paper, Sereno and colleagues agreed with Charig and Milner that there were no significant differences between the fossil skulls of Baryonyx and Cristatusaurus, concluding that the latter should be regarded as a nomen dubium.

In 2002, French paleontologist Éric Buffetaut and his Tunisian colleague Mohamed Ouaja expressed support for the proposed synonymy between Cristatusaurus and Baryonyx, noting that Milner had acknowledged the possibility that Suchomimus might also be congeneric with Baryonyx with later anatomical comparisons. The same year, American paleontologist Hans-Dieter Sues and colleagues concluded that S. tenerensis was sufficiently similar to B. walkeri to be placed within the same genus, renamed as Baryonyx tenerensis, and that it was likely identical to Cristatusaurus. These interpretations were also concurred by Milner in 2003. In a conference abstract released the following year, American paleontologist Stephen Hutt and British researcher Penny Newbery also supported the synonymy based on a large theropod vertebra discovered on the Isle of Wight, England, which they attributed to an animal closely related to these two taxa. Nevertheless, subsequent studies have continued to treat Suchomimus and Baryonyx as separate genera. A 2017 review paper by the Brazilian palaeontologist Carlos Roberto A. Candeiro and colleagues stated that this debate was more in the realm of semantics than science, as it is generally agreed that Suchomimus and Baryonyx are distinct, related genera. As for the validity of Cristatusaurus, it continues to be disputed in recent studies. This taxon is generally regarded as a likely senior synonym of Suchomimus, as both originate from the same stratigraphic units and show no sufficiently distinct anatomical differences to justify a clear separation between them. Thus, Cristatusaurus is currently considered a nomen dubium, pending further analyses that could clarify its taxonomic position. However, in the event that the synonymy between the two genera is confirmed, nomenclatural priority would normally be given to C. lapparenti, as it was described earlier than S. tenerensis.

Suchomimus would have reached 9.5–11 metres (31–36 ft) in length and weighed 2.5–3.8 metric tons (2.8–4.2 short tons). Canadian paleontologists François Therrien and Donald M. Henderson proposed that a 10.3 metres (34 ft) long Suchomimus would have weighed more than 5.3 metric tons (5.8 short tons) based on their ratio between skull length and body length; however, they noted that they might have overestimated the size of spinosaurids (i.e., Suchomimus and Baryonyx). The holotype specimen of Suchomimus is considerably larger than that of Baryonyx, although this may be explained by the possibly immature status of the latter.