The “Megafauna” of Madagascar

Ahh, Madagascar.  I fell in love when I got my first issue of Ranger Rick and got a glimpse of fascinating creatures that my seven-year-old self hadn’t even imagined: Tomato frogs, chameleons the size of your thumbnail, and of course the lemurs!  Who doesn’t love a lemur?  I challenge anyone to watch a sifaka hop from one tree to the next on the ground and not crack a smile.  Likewise with ringtails rubbing their wrists on their tails to spread their pheromones.  And don’t even get me started on the Aye-aye!

It seems like Madagascar has an endless supply of lemur diversity.  But, as it turns out, the lemurs alive today are only part of the picture.  As recently as 1000-500 years ago, there were giant lemurs living in Madagascar.  That’s so recent that the bones we find from these animals have only just begun the process where organic tissue from the bones is replaced by inorganic mineral from the surrounding dirt.  They aren’t even fossils yet, so we call them “subfossils.”  It’s hard to say whether or not humans had a role in their extinction or not, but the timing is fairly suspect.

Daubentonia robusta

We’ve found a giant Aye-aye, Daubentonia robusta, with the same elongated middle finger and perpetually growing incisors as the extant aye-aye Daubentonia madagascariensis. Giant Aye-aye teeth have been found with holes drilled in them for use in jewelry, which suggests that they probably lived alongside the first human inhabitants of Madagascar 2000 years ago.  The Giant Aye-ayes weighed up to 5 times as much as the extant ones, but still had all of the adaptations for insect foraging, which is strange because usually only small mammals can survive on insects.

There were also the Megaladapis species, or the Koala lemurs.  Members of the Megaladapis genus had long arms and long fingers and short legs, which were perfect for clinging vertically to trees and slowly munching on leaves, just like koalas.  Unfortunately, it also probably made them pretty vulnerable to human hunters.

Paleopropithecus ingens, from the Animal Diversity Web at UM

There were the sloth lemurs, a taxonomic group which includes four different genera.   Members of the genus Paleopropithecus were roughly chimpanzee-sized lemurs.  They’ve been reconstructed as they Malagasy version of the tree sloth because of their extremely long arms and long, curved fingers.  They probably used their hands and feet as a sort of grappling hook and hung upside-down, or antipronograde, as they foraged for leaves.

And there was Archaeoindris, another genus of sloth lemur.  Archaeoindris was a gorilla-sized lemur!  It’s still debated whether it was confined to the ground because of it’s huge size, or whether the curved phalanges suggest that maybe it, too lived in the trees.

So, with all of that in mind, Livescience is reporting the discovery of a new giant lemur, Paleopropithecus kelyus. P. kelyus is now the third and smallest member of the genus Paleopropithecus, which were the upside-down, sloth-like creatures from above.  The livescience article reports that certain features of the teeth suggest that it ate tougher foods like seeds instead of or in addition to leaves, but once again, I can’t find the original article yet.  Anyone know where it is?

• William L. Jungers, Laurie R. Godfrey, Elwyn L. Simons, and Prithijit S. Chatrath (1997).  Phalangeal curvature and positional behavior in extinct sloth lemurs (Primates,Palaeopropithecidae). Proc Natl Acad Sci U S A: 94(22): 11998–12001.
• Godfrey, Laurie R., William L. Jungers. (2003). “The extinct sloth lemurs of Madagascar”. Evolutionary Anthropology 12: 252–263. doi:10.1002/evan.10123
• Fleagle, J.G. 1988. Primate Adaptation and Evolution. Academic Press: New York.
• Simons, EL (1994). “The giant aye-aye Daubentonia robusta“. Folia Pimaol (Basel) 52 (1-3): 14–21