Carcharhiniformes
| Ground sharks Temporal range: | |
|---|---|
| A finetooth shark, Carcharhinus isodon | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Clade: | Neoselachii |
| Subdivision: | Selachimorpha |
| Superorder: | Galeomorphii |
| Order: | Carcharhiniformes Compagno, 1977 |
Carcharhiniformes /kɑːrkəˈraɪnɪfɔːrmiːz/, the ground sharks, are the largest order of sharks, with over 270 species. They 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.
The oldest members of the order appeared during the Middle-Late Jurassic, which have teeth and body forms that are morphologically similar to living catsharks. Carchariniformes first underwent major diversification during the Late Cretaceous, initially as mostly small-sized forms, before radiating into medium and large body sizes during the Cenozoic.