Tiny monkey teeth suggest Flores hobbit was a dwarf

COULD the world's tiniest monkey help unravel the mysterious origins ofHomo floresiensis, the "hobbit" human relative?

The hobbit's skull is similar to that of a taller hominin, Homo erectus. This suggests to some that H. floresiensis, whose remains were found on an Indonesian island 10 years ago, was a dwarf species that evolved from this larger one. However, its brain and teeth are proportionally much smaller than in typical dwarf species, which others say indicates the hobbit is merely an unusual form of our species. But perhaps the hobbit was not a typical dwarf.

Stephen Montgomery and Nicholas Mundy at the University of Cambridge looked at pygmy marmosets (Callithrix pygmaea). They too have previously been put forward as a dwarf species but, again, have unusually small teeth.

"This pointed against dwarfism," says Montgomery. Now, using a primate evolutionary tree, the pair have confirmed that these monkeys did indeed evolve from larger ancestors and undergo dwarfism.

So why the small teeth? The evolution of a dwarf species usually involves shortening the length of pregnancy or infancy, but recently it has been suggested that there might be a more unusual route: pregnancy length stays the same but the growth of the fetus slows down. This might influence brain and tooth size as these develop early.

Montgomery and Mundy found that the pygmy marmoset's pregnancy and infancy are similar in length to their evolutionarily close, larger relations. This suggests they took the unconventional route to small stature (Journal of Evolutionary Biology, doi.org/kpc).

Read on: http://www.newscientist.com/article/mg21729074.300-tiny-monkey-teeth-suggest-flores-hobbit-was-a-dwarf.html