STONE, R. DOUGLAS. Department of Integrative Biology and University - Jepson Herbaria, University of California, Berkeley, CA 94720. - Southern hemisphere biogeography: phylogenetic evidence from angiosperms and other groups.
Cladistic methods were used to infer the Mesozoic and Cenozoic history
of the major southern hemisphere land areas. The study included
reduced area cladograms for ten putative "Gondwanan" groups,
including the angiosperm taxa Winteraceae and
Proteaceae: Macadamieae. Brooks parsimony analysis
produced a single most parsimonious tree that resolves the area
relationships (southeastern Asia (India (Africa, Madagascar) (South
America, Australia))). A proposed Tertiary land connection between
Africa and Madagascar may help to explain their inferred sister
relationship. Coding of Madagascar as a composite area also yielded a
single tree differing only by the addition of Madagascar 2 as sister
to India. Hovenkamp's (1997) vicariance analysis failed to resolve a
general area cladogram because of conflicting area relationships and
occurrence of sympatric (redundant) or widespread taxa in the source
cladograms. The area relationships inferred using Brooks parsimony are
more-or-less congruent with a model of Gondwanaland fragmentation
derived from independent geological evidence. Brooks parsimony under a
topological constraint corresponding to a hierarchical earth history
model yielded a tree five steps longer than in the unconstrained
analysis. Similarly constrained analyses of multiple randomizations of
the source data failed to produce any trees as short as the
"real" one, which evidently lies on the tail of a null
distribution of tree lengths. The biogeographic pattern in the
phylogenetic data examined is thus consistent with a vicariance
hypothesis.
Key words: Gondwanaland, historical biogeography, Proteaceae, vicariance biogeography, Winteraceae