Habitats of Madagascar and species locations.
From Yoder et al., 2016
Some of the world's top lemur experts have provided us with new information on the history of Madagascar's forests. Yoder and colleagues (2016) looked at the DNA of five different species of mouse lemurs, a genus dependent on the forest, to understand how the forests across this island nation changed. One of their research questions asks if the divide between the two forest habitats is natural or what remains of a transitional cline?
Results suggest that the five species studied started diverging from one another roughly five hundred and forty thousand years ago with the last node of divergence around fifty-five thousand years ago. The timing of mouse lemur evolution and divergence coincides with evidence suggesting great variation in climate.
|M. murinus. Photo: Joachim S. Muller|
Genetic analysis of M. myoxinus, a subspecies of mouse lemur that lives in continuous forests, and M. lehilahytsara, another subspecies that lives in a mosaic of forests, show significantly different patterns in regards to geographic patterns of divergence. Results suggest that M. lehilahytsara, the mouse lemur in a mosaic of forests, has lived in this type of habitat for a very long period of time, since before the arrival of humans. Thus, genetic evidence from mouse lemurs does not support the forest hypothesis.
Yoder and colleagues (2016) also discovered that M. berthae and M. rufus are more closely related than would be expected, given their geographic differences. One species lives lives in the southeast in humid forests and the other in dry forests of the west. This close genetic relationship points towards the mosaic hypothesis of Madagascar's ancient geography. We see a genetic divergence that is tens of thousands of years old and not uniform across all Microcebus species.
Thus, using the genes of mouse lemurs, Yoder and colleagues (2016) were able to conclude that the central part of Madagascar was composed of a mosaic habitat composed of forests and grasslands. The arrival of humans does not appear to have caused a tremendous change from an entirely forested landscape to grasslands similar to what we see today.
Links of possible interest:
Ecosystems in Madagascar
Read the paper here
They may be cute, but you shouldn't have a primate as a pet
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Yoder, A. D., Campbell, C. R., Blanco, M. B., dos Reis, M., Ganzhorn, J. U., Goodman, S. M., ... & Ralison, J. M. (2016). Geogenetic patterns in mouse lemurs (genus Microcebus) reveal the ghosts of Madagascar's forests past. Proceedings of the National Academy of Sciences, 201601081.