Geography Reference
In-Depth Information
taxa, especially the Wallacea and the Central American-Mexican, currently
known as the Mexican Transition Zone (Halffter 1987; Morrone 2006).
Darlington (1965) published
Biogeography of the Southern End of the
World,
in which he held that many plants and invertebrates of southern
South America, southern Australia, Tasmania, and New Zealand are phylo-
genetically related, whereas this pattern does not occur for vertebrates (ex-
cept for some salt-tolerant fishes). Rainfall, cold, and other climatic and eco-
logical factors affect the distribution of life in the far south now and have
probably done so in the past. Southern distributions should be analyzed in
relation to the whole world. Distribution of different taxa should be analyzed
case by case to see whether they have diverse patterns (suggesting dif-
ferent histories) or common patterns (suggesting a common history). Dar-
lington (1965) concluded that no great changes in the arrangement of the
southern continents seem possible in the Late Cretaceous (except possibly
the making and breaking of an isthmian link between Antarctica and south-
ern South America). Several plant and animal taxa have been arriving con-
tinually from the north. Some groups of plants and invertebrates have been
especially adapted and confined to the southern continents, where a char-
acteristic far southern biota evolved, especially in wet forests and wet moor-
lands. Interestingly, in the conclusion of the topic, he stated,
Evidence from several independent sources, discussed and com-
pared in preceding chapters, has forced me to conclude that the
southern continents have drifted. I have therefore become a We-
generian, but not an extreme one. I doubt the former existence of a
Pangaea or Gondwanaland, and I think that movements of contin-
ents have been simpler and shorter than most Wegenerians support.
Also, I am not absolutely sure of my conclusions. I shall therefore
state the conclusions as probabilities rather than proven facts. (Dar-
lington 1965:210)
