Antitropical (alternatives include biantitropical or amphitropical) distribution is a type of
disjunct distribution
In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but considerably separated from each other geographically. The causes are varied and might demonstrate either the expansion or contraction of a s ...
where a
species or
clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
exists at comparable
latitudes across the
equator
The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...
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. With increasing time since
dispersal, the disjunct populations may be the same variety, species, or clade.
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 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. For the American amphitropical distribution, dispersal has been generally agreed to be more likely than
vicariance
Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...
from a previous distribution including the tropics in North and South America.
Known cases
Plants
* ''
Phacelia crenulata
''Phacelia crenulata'' is a species of flowering plant in the borage family, Boraginaceae. Its common names include notch-leaf scorpion-weed,[Bowlesia incana
''Bowlesia incana'' is a species of flowering plant in the family Apiaceae known by the common name hoary bowlesia. It is native to South America and the southeastern and southwestern United States as far north as Oregon. It can also be found in ...]
'' – American Bowlesia
* ''
Osmorhiza berteroi
''Osmorhiza berteroi'' is a species of flowering plant in the family Apiaceae known by the common name mountain sweet cicely.
Systematics
''Osmorhiza berteroi'' forms a species complex together with '' O. depauperata'' and '' O. purpurea''. Un ...
'' and ''
Osmorhiza depauperata
''Osmorhiza depauperata'' is a species of flowering plant in the carrot family known by the common names bluntseed sweetroot and blunt-fruited sweet-cicely.
Distribution and habitat
The plant is native to much of western and northern North Amer ...
'' – sweet cecily species.
* ''
Ruppia megacarpa
''Ruppia megacarpa'' is a submerged herb species in the genus ''Ruppia'' found in shallow brackish waters. It is a common on Australasian coasts, including Australia (NSW; SA; Vic
Vic (; es, Vic or Pancracio Celdrán (2004). Diccionario de ...
''
* ''
Solenogyne
''Solenogyne'' is a genus of Australian plants in the tribe Astereae within the family Asteraceae.econd edition">Cassini, Alexandre Henri Gabriel de. 1828. Dictionnaire des Sciences Naturelles [Second edition/nowiki> 56: 174-176in French
; Speci ...
''
*For a list of American amphitropically distributed plants (237 vascular plants), see the tables in the open access paper Simpson et al. 2017
or their working group on figshare
Animals
* ''Scylla serrata'' – mud crab
* Crayfish, Freshwater crayfish
* Ground beetle genus ''Bembidion''
Bryophytes and lichens
* ''Tetraplodon (plant), Tetraplodon fuegianus''
- dung moss
See also
*
Rapoport's rule
References
Biogeography
{{Ecology-stub