Carchariidae is a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

lamniform The Lamniformes (, from Greek ''lamna'' "fish of prey") are an order of sharks commonly known as mackerel sharks (which may also refer specifically to the family Lamnidae). It includes some of the most familiar species of sharks, such as the g ...

shark Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the ...

s containing a single extant genus, '' Carcharias'', The family was recognized as distinct as early as 1838, but afterwards, it was grouped with the superficially very similar genus ''

Odontaspis ''Odontaspis'' (from 'tooth') and 'shield') is a genus of sand shark with two extant species. Description Bigeye sand tigers can reach a length of about and smalltooth sand tigers of about 4.1 m. They are large-bodied sharks with l ...

'' into the family Odontaspididae. However, phylogenetic studies since the 21st century have discovered that this placement is

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

, with ''Carcharias'' being the second most basal extant lamniform after the goblin sharks, while ''Odontaspis'' diverged from the rest of the lamniforms only afterwards, and is thus more closely related to derived lamniforms. For this reason, the family Carchariidae was revived in 2019, and is presently accepted by ''

Eschmeyer's Catalog of Fishes Catalog of Fishes is a comprehensive on-line database and reference work on the scientific names of fish species and genera. It is global in its scope and is hosted by the California Academy of Sciences. It has been compiled and is continuously up ...

'' and the Shark-References database. Aside from the stratigraphically widespread genus ''Carcharias'', known from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

onwards based on named species, the paleontological history of this family is uncertain due to the close similarity of its teeth with those of the Odontaspididae, which was why the two families were long confused. It is possible that some families placed in Odontaspididae may actually belong in Carchariidae. In 2020, the genus '' Araloselachus'' was recognized as an extinct member of the Carchariidae, although some authorities like the Shark-References database retain it in the Odontaspididae. The distinctiveness of the Carchariidae makes the conservation of its only surviving member, the highly endangered ''Carcharias'', even more of a priority, as its extinction would mean the loss of an ancient family that has existed since the Cretaceous.

References

{{Lamniformes Shark families Cretaceous first appearances Lamniformes