Anthropoids -- a large group of extant and fossil primates that includes monkeys,
apes, and humans -- arose about 45 to 55 million years ago (Ma) in Africa or Asia
, but much of their history prior to about 35 Ma is poorly understood. In a Report
in the 14 Oct 2005 *Science*, Seiffert et al. (http://www.sciencemag.org/cgi/content/short/310/5746/300)
described the earliest and most complete African anthropoid fossils from the Fayum
desert region of Egypt. The fossils are about 37 million years old and consist
of small teeth and jawbones from two tiny monkey-like creatures of the genus *Biretia*.
Interestingly, one of the creatures appears to have been nocturnal, the first
example of a nocturnal early anthropoid. The fossil teeth share some key features
with African fossils more than 45 million years old and with other, much younger
anthropoids, drawing all of these taxa into a diverse group with surprising antiquity.
The team's phylogenetic analysis is also consistent with the view that African
anthropoids immigrated from Asia at a very early date, probably before the late
Paleocene (60 Ma). However, it is also possible that there were several waves
of Asian immigrations. As noted in an accompanying Perspective by J.-J. Jaeger
and L. Marivaux (http://www.sciencemag.org/cgi/content/short/310/5746/244),
a more complete fossil record will be needed to bridge the remaining gaps in our
understanding of anthropoid history.