Speciation and hybridization in early and late Homo species
This week we will read about variation in human skull fossils and its connection with species diversity in early Homos (A Complete Skull from Dmanisi, Georgia, and the Evolutionary Biology of Early Homo - Science 2013), and to add to that, another small perspective paper on hybridization in archaic humans (Did the Denisovans Cross Wallace's Line? - Science 2013), which will surely provide plenty of material for a very interesting discussion. All from the latest issue of Science.
A Complete Skull from Dmanisi, Georgia, and the Evolutionary Biology of Early Homo (Lordkipanidze et al. 2013).
The site of Dmanisi, Georgia, has yielded an impressive sample of hominid cranial and postcranial remains, documenting the presence of Homo outside Africa around 1.8 million years ago. Here we report on a new cranium from Dmanisi (D4500) that, together with its mandible (D2600), represents the world's first completely preserved adult hominid skull from the early Pleistocene. D4500/D2600 combines a small braincase (546 cubic centimeters) with a large prognathic face and exhibits close morphological affinities with the earliest known Homo fossils from Africa. The Dmanisi sample, which now comprises five crania, provides direct evidence for wide morphological variation within and among early Homo paleodemes. This implies the existence of a single evolving lineage of earlyHomo, with phylogeographic continuity across continents.