Cambaridae
The Cambaridae are the largest of the three families of freshwater crayfish, with over 400 species. Most of the species in the family are native the United States east of the Great Divide and Mexico, but fewer range north to Canada, and south to Guatemala and Honduras. Three live on the island of Cuba. The species in the genus Cambaroides are the only found outside North America, as they are restricted to eastern Asia.
A few species, including the invasive Procambarus clarkii and Orconectes rusticus, have been introduced to regions outside their native range. Conversely, many species have tiny ranges and are seriously threatened; a few are already extinct.
A 2006 molecular study suggested that the family Cambaridae may be paraphyletic, with the family Astacidae nested within it, and the status of the genus Cambaroides remains unclear.
