Bull shark: 130 kg
| Requiem shark, Hammerhead shark, Catshark, Houndshark, Smooth‑hound|
The ground sharks, order Carcharhiniformes, are the largest order of sharks. With over 270 species, carcharhiniforms include a number of common types, such as catsharks, swellsharks, and the sandbar shark.
Members of this order are characterized by the presence of a nictitating membrane over the eye, two dorsal fins, an anal fin, and five gill slits.
The families in the order Carcharhiniformes are expected to be revised; recent DNA studies show that some of the conventional groups are not monophyletic.
According to FishBase, the eight families of ground sharks are:Carcharhinidae (requiem sharks)
Hemigaleidae (weasel sharks)
Leptochariidae (barbeled houndshark)
Proscylliidae (finback catsharks)
Pseudotriakidae (false catsharks)
Sphyrnidae (hammerhead sharks)