Last week, a paper in Science announced the discovery of the most complete hominin cranium ever found from the Early Pleistocene. The Dmanisi fossils, the earliest known hominins outside of Africa, have long been remarked upon for their apparent inter-individual morphological diversity, as well as retention of seemingly "primitive" traits like small relative brain size. The individual that the newly-described Dmanisi "Skull Five" belonged to lived at the same time as Homo erectus, but as is clear from this latest publication, possessed a remarkably small braincase and a large, prognathic lower face. The contrast between this specimen's features with those of its known Homo coevals prompted its discoverers to advocate for the collapse of all early Homo taxa into a single, variable species.
In a cleverly-named opinion piece in this week's nature, Fred Spoor argues that this conclusion is premature. He finds fault with Lordkipanidze et al.'s phenetic analysis of the specimen's morphology, and argues that a character-based cladistic approach is necessary. He further points out that the fossil shows a combination of primitive and derived traits. This suggests that Skull Five is not best lumped in with other primitive Homo, but rather that it exhibits a relatively primitive Homo erectus-specific morphology, as has been observed and may, under certain models of speciation, be expected on the periphery of the Homo erectus range.
This issue of nature also contains a special supplement on Transcription and Epigenetics, which may be of interest.