Introduction Homo ergaster is one of the more problematic of somewhat accepted species designations currently tossed around in anthropological literature. Each individual researcher that sees ergaster as a valid taxon sees different specimens as belonging or not belonging to the taxon.
Many researchers deny any validity to the species at all.
On the whole though, most researchers see too little difference between ergaster and erectus to form the basis of a species of the former, separated from the latter. The taxon ergaster was first described in 1975 by C. Groves and V. Mazak. The specimen attributed as the type specimen was ER 992, an isolated mandible. Since then, other specimens have been attributed by various authors to ergaster , with most researchers placing the same fossils in erectus . Those who see it as a valid taxon tend to see it as more closely resembling modern H. sapiens than does H. erectus .