Geography Reference
In-Depth Information
duced by the uplift of the Andes and the expansion of the Chacoan biota (Kuschel
1969). A PAE based on species of anurans (Ron 2000) showed the close rela-
tionship between the Parana and Amazonian subregions. The Parana subregion
comprises three provinces: Brazilian Atlantic Forest, Parana Forest, and
Araucaria
angustifolia
.
The South American Transition Zone extends along the highlands of the Andes
between western Venezuela and northern Chile and west central Argentina. The
Prepuna, Coastal Peruvian Desert, and Monte provinces, previously assigned to
the Neotropical region, are assigned to this transition zone on the basis of their
close biotic links with the Puna and North Andean Paramo. Because of the pree-
minence given to some tropical cenocrons, Cabrera and Willink (1973) assigned
the North Andean Paramo to the Neotropical region; its close relationships with
other Paramo Punan provinces led other authors to place it in the Andean region.
Six provinces are assigned to the South American Transition Zone: North Andean
Paramo, Puna, Coastal Peruvian Desert, Atacama, Prepuna, and Monte.
The Andean region extends to central Chile and Patagonia. Many insect spe-
cies are common to this region and the South American Transition Zone. Most
of the Andean biota originally evolved in Patagonia and then gradually spread
north into the South American Transition Zone during the Tertiary and Pleisto-
cene, when tropical forests evolved to temperate and arid communities. Brundin
(1966) documented the relationships between the Austral continents in his phylo-
genetic analysis of some Chironomidae (Diptera) from New Zealand, Australia,
Patagonia, and South Africa. Edmunds (1972) corroborated these connections on
the basis of phylogenetic evidence from mayflies (Ephemeroptera). More recent
biogeographic studies searched for congruence between distributional patterns of
insects and other animal and plant taxa. Two cladistic biogeographic analyses
based on plant, fungal, and animal taxa (Crisci et al. 1991b; Sanmartín and Ron-
quist 2004) showed that South America is a composite area because southern
South America is more closely related to the southern temperate areas that cor-
respond to the Austral realm, whereas tropical South America is more closely re-
lated to Africa and North America. Other cladistic and panbiogeographic studies
(Katinas et al. 1999; Lopretto and Morrone 1998; Morrone 1996; Patterson 1981)
also support the hypothesis that South America is a composite area, with the An-
dean region closely related to the southern temperate areas and the Neotropical
region closely related to the Old World tropics. The Andean region comprises the
Central Chilean, Subantarctic, and Patagonian subregions.
The Central Chilean subregion extends to central Chile, between latitudes 30°
and 34° south. PAE and cladistic biogeographic analyses based on extant arthro-
pod and plant taxa (Carvalho and Couri 2002; Marino et al. 2001; Morrone 1994a;
Morrone et al. 1997; Posadas and Morrone 2003) showed that this subregion is
closely related to the Subantarctic subregion. The close relationship between the
Central Chilean subregion and the northern part of the Subantarctic subregion
