Biantitropical distribution

Biantitropical (or amphitropical) distribution refers to the pattern of species that exist at comparable latitudes across the equator but not in the tropics. For example, a species may be found north of the Tropic of Cancer and south of the Tropic of Capricorn, but not in between. This usually has to do with the optimal temperature for the species existing at both latitudes. How the life forms distribute themselves to the opposite hemisphere when they can't normally survive in the middle depends on the species; plants may have their seed spread through wind, animal, or other methods (dispersal) and then germinate upon reaching the appropriate climate, while sea life may be able to travel through the tropical regions in a larval state or by going through deep ocean currents with much colder temperatures than on the surface.

Known cases of antitropical distribution

Plants

• Phacelia crenulata - scorpionweed
• Bowlesia incana - American Bowlesia
• Osmorhiza berteroi and Osmorhiza depauperata - sweet cecily species.
• Ruppia megacarpa
• Solenogyne

Animals

• Scylla serrata - mud crab
• Freshwater crayfish
• Ground beetle genus Bembidion

See also

• Rapoport's rule