Geography Reference
In-Depth Information
the relationship between phylogenetics and biogeography.” In fact, Croiz-
at(1958b)clearlydistinguishedbetweenancestor-descendantrelationships
and common ancestry, something that even today may not be clear to some
practicing systematists.
Craw (1988a) justified the panbiogeographic approach, applying the
Hennigian concept of reciprocal illumination to systematics and biogeo-
graphy. Panbiogeography assumes that spatial relationships can suggest
genealogical relationships. A classic example is the redefinition of the taxo-
nomic relationships between carnivorous plants by Croizat, based on their
spatial relationships. Nevertheless, Platnick and Nelson (1988) noticed that
Croizat did not base his conclusions exclusively on geographic proximity but
took morphological characters into consideration to regroup them. Cladists
accept that the incongruence of a taxon with a recognized biogeographic
pattern may suggest an incorrect systematic hypothesis, but the incongru-
ence by itself does not constitute evidence. Any congruence revealed by
panbiogeography will be uncertain because it is possible that it is produced
by geographic proximity, and even assuming that the construction of tracks
may reveal causal connections between areas, they are unable to reveal
their exact relationship (Platnick and Nelson 1988).
Argentinean paleontologist and evolutionary biologist Osvaldo Reig
(1929-1992) made some important contributions to biogeography. Reig
(1962:132-133) published a brief article in which he introduced some preci-
sions on biogeographic concepts:
All modern and scientific biogeographic research is born from a com-
mon theory to all biology, the theory of evolution, where the historic-
al, genetic and dynamic conceptualization is the starting point. At the
present time there cannot be any branch of biogeography that does
not bear these attributes, because the mere configuration of distribu-
tion data presupposes an historical theory with whose aid facts are
interpreted.
Reig thought that referring to “historical biogeography” disregarded the
fact that the objects of inquiry are communities. He introduced the term
cenogenesis
(originally coined by Sukachev 1958) to refer to “the devel-
