Geography Reference
In-Depth Information
Empirical Applications
Folinsbee and Brooks (2007).
The family Hominidae (Primates), comprising apes and humans, exhibits a com-
plex history of dispersal and speciation events over large areas of the Old World
in the last 25 million years. Folinsbee and Brooks (2007) integrated phylogenetic
data of hominines, hyaenids (hyenas), and proboscideans (elephants) with paleo-
climatological, paleoenvironmental, and geological evidence in order to provide a
general hypothesis explaining their biogeographic history.
Folinsbee and Brooks (2007) analyzed the cladograms of the superfamily
Hominoidea, the family Hyaenidae, and the order Proboscidea. These taxa share
broadly similar habitat preferences and are frequently found at the same fossil
localities, indicating that they might have shared biogeographic distribution in the
past. The authors used PACT software (Wojcicki and Brooks 2004, 2005) to obtain
a general area cladogram.
Analysis of the three area cladograms (
figs. 5.24a
-
5.24c
) with PACT produced
a single general area cladogram (
fig. 5.24d
), which is rather complex, with many
area reticulations and widespread taxa, especially among the proboscideans.
When first appearance dates inthe fossil recordaremapped onto the general area
cladogram to provide minimum ages for each node, usually the oldest taxa appear
at the base and the youngest at the apical end; however, some of the dates do not
correlate at all. Of the nodes in the general area cladogram, seventeen are associ-
ated with concurrent events in all three clades, nine are associated with events in
two clades, and eight are associated with an event involving a single clade. Some
of the twenty-six nodes involving at least two of the three clades, designated by
the authors as general nodes, are vicariance nodes; others are biotic expansion
nodes and widespread taxa. Hominoids, proboscideans, and hyaenids may have
been associated in Africa at least as early as the early Miocene, followed by an
“out of Africa” expansion into Europe, Asia, and North America; a second general
episode of species formation in Asia in the mid-Miocene; and another “out of Asia”
expansion into Africa, Europe, and North America. Finally, there were two addi-
tional “out of Africa” events in the Late Miocene and Pliocene, the last one setting
the stage for the emergence and spread of the genus
Homo
. In addition to the
common episodes of vicariance and dispersal, each group exhibits clade-specific
within-area and peripatric speciation events.
