Sarcosuchus imperator, often nicknamed "SuperCroc," was an enormous crocodile relative that lived in what's now Africa roughly 112 to 97 million years ago, during the Early Cretaceous.
A crocodile relative on a different scale
Large Sarcosuchus individuals are estimated to have reached roughly 9 to 10 meters (30–33 ft) long — around twice the length of the largest modern crocodiles. Its skull alone could grow well over a meter and a half long, noticeably longer and proportionally different from any crocodile skull alive today.
Not quite a modern crocodile
Like Deinosuchus in North America, Sarcosuchus belonged to an earlier branch of the crocodilian family tree rather than being a direct ancestor of today's crocodiles and alligators. Researchers believe it was an ambush predator, likely lurking in rivers and lakes to attack whatever large prey came close to the water's edge, including dinosaurs.
What its fossils reveal
Much of what's known about Sarcosuchus comes from expeditions in Niger led by paleontologist Paul Sereno in the 1990s and 2000s, which recovered a substantial portion of its skeleton — unusually complete for an animal this old, and part of why it's one of the better-understood giant crocodile relatives in the fossil record.