Murrill (1981) proposed the name Homo petralonensis conditionally; it is therefore unavailable. Specifically, he writes, "consequently, the time factor becomes important. If the dating for Petralona 1 is as old as 700,000 years B.P., and if sub-specific names are most appropriately used geographically then I would say Petralona 1 should be classified as Homo erectus petralonensis, or given Petralona 1's similarity to Broken Hill 1, and the possibility Petralona 1 may have migrated from Africa--Homo erectus rhodesiensis." (p. 256)