Carcharodon hastalis is an extinct species of mackerel shark that lived between thirty and one million years ago during the late Oligocene to the Early Pleistocene epochs.
Its teeth can reach lengths up to 3.5 in (7.5 cm) and are found worldwide. It is believed to be an ancestor to the modern day great white shark, an argument supported by the transitional species Carcharodon hubbelli,
C. hastalis was a confirmed hunter of marine mammals. It most likely would have been one of the major predators in its ecosystem, preying upon small whales and other mammals. Trace fossils in the form of tooth marks on the bones of a Pliocene dolphin of the species Astadelphis gastaldii reveal that C. hastalis attacked its prey from below and behind, much like the modern great white shark does. The deepest bite marks on the dolphin's ribs indicate the shark aimed for the abdomen of its prey to inflict a fatal bite quickly and incapacitate its prey, and that when the dolphin was attacked a second time, it was bitten near the dorsal fin, suggesting that the dolphin rolled over while injured. The size of the bites indicates further that the shark responsible was estimated to be long.
A well-preserved skeleton of a juvenile C. hastalis from Peru described in 2017 showcases that the shark also included fish in its diet. Stomach contents preserved with the fossil show this shark also fed on pilchards such as ancient sardines (genus Sardinops), suggesting bony fish featured prominently in the shark's diet while it was young.
Carcharodon hastalis teeth can grow up to in length, suggesting a very large shark. Its body was probably very similar to that of modern great whites. It is also believed to have a cosmopolitan distribution, with C. hastalis teeth being found worldwide. The maximum adult length is estimated between . Smaller individuals were about long.