Cancridae is a family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of crab

Crab

True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...

s. It comprises six extant genera, and eleven exclusively fossil genera, in two subfamilies:
Cancrinae Latreille, 1802

• Anatolikos Schweitzer & Feldmann, 2000
• †Anisospinos Schweitzer & Feldmann, 2000
• Cancer
  Cancer (genus)
  Cancer is a genus of marine crabs in the family Cancridae. It includes 8 extant species and 3 extinct species, including familiar crabs of the littoral zone, such as the European edible crab , the Jonah crab and the red rock crab...
  
  Linnaeus, 1758
• †Ceronnectes De Angeli & Beschin, 1998
• †Cyclocancer Beurlen, 1958
• Glebocarcinus
  Glebocarcinus
  Glebocarcinus is a genus of crabs formerly included in the genus Cancer, containing two species:*Glebocarcinus oregonensis *Glebocarcinus amphioetus...
  
  Nations, 1975
• Metacarcinus
  Metacarcinus
  Metacarcinus is a genus of crabs formerly included in the genus Cancer. It includes nine exclusively fossil species and five extant species, of which four are also known from the fossil record...
  
  A. Milne-Edwards, 1862
• †Microdium Reuss, 1867
• †Notocarcinus Schweitzer & Feldmann, 2000
• Platepistoma Rathbun, 1906
• Romaleon
  Romaleon
  Romaleon is a genus of marine crabs formerly considered in the genus Cancer.-Species:The genus, as currently circumscribed, contains seven species:*Romaleon antennarium Stimpson, 1856*Romaleon branneri Rathbun, 1926...
  
  Gistel, 1848
• †Santeecarcinus Blow & Manning, 1996
• †Sarahcarcinus Blow & Manning, 1996

†Lobocarcininae Beurlen, 1930

• †Lobocarcinus
  Lobocarcinus
  Lobocarcinus is a genus of extinct marine crabs that lived in the Eocene and Miocene, containing the following species:*Lobocarcinus lumacopius* Lobocarcinus pustulosus* Lobocarcinus paulinowurtemberbensis* Lobocarcinus indicus...
  
  Reuss, 1857
• †Miocyclus Müller, 1978
• †Tasadia Müller in Janssen & Müller, 1984

Before 2000, the extant species were all placed in a single genus, but in that year Carrie Schweitzer and Rodney Feldmann elevated the existing subgenera to the rank of genus, and described three additional genera. Most of the family's current diversity is found in temperate waters of the Northern Hemisphere

Northern Hemisphere

The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...

.