That diversity continues to expand. The last exhaustive analysis of Africa's rodents was carried out by R. Lavocat in 1978. At that time scientists recorded 54 genera, 76 fewer than those documented by Winkler, Denys and Avery in their analysis.
Winkler and her colleagues summarize the distribution and ecology of existing rodent families, as well as the systematics, biochronology and paleobiogeography of rodent families in Africa's fossil record. The diversity they document reflects "the wide variety of habitats present on the continent" and paints a picture of Africa's paleoecology.
Given the huge rodent diversity in modern Africa, "it is likely that such an extensive fauna was also present in the past," the scientists write.
Tremendous diversity reflects wide variety of habitats
An example of that relationship is the scaly-tailed flying squirrel, an exclusively African group of forest-dwelling rodents that are not related to true squirrels. They are well known from about 18 million to 20 million years ago in eastern Africa, Winkler says, suggesting the presence of closed habitats, such as forests. That corroborates other evidence of forests from fossil animals, plants and geology, she says.
"Although there are even older scaly-tailed flying squirrels known from the currently arid regions of northern Africa," says Winkler, "they do not appear to have been gliders, as are most current forms, and the question of when members of the group first developed gliding locomotion still remains."
|Contact: Margaret Allen|
Southern Methodist University