Mallory's dating, which presupposes that Proto-Anatolian, Proto-Indo-Iranian, Greek and other descendant languages could have diverged from each othe… - Aharon Dolgopolsky

If a given proto-language was spoken in an area outside that of its daughter languages, specific words designating features of the ancient habitat are not usually preserved in the attested languages. Therefore, if a language ancestral to a group of European languages originated in Africa, we would not be able to find in the extant lexical stock ancient words for "giraffe" and "elephant" which could suggest its African origin. (Dolgopolsky 1987, 8)

Dolgopolsky, believes the terms for material culture commonly used to date Proto- Indo-European, such as copper, horse, and wheeled vehicles, cannot be reconstructed in the Anatolian languages and therefore belong to a later, post-Hittite Indo-European and not Proto-Indo-European. Proto-Indo-European, accordingly, did not know all these items, since it was much earlier. He reiterates the arguments outlined previously, suggesting that the horse known to the Proto-Indo-European's was not the domesticated but the wild variety, and claims that the word *ayes did not originally refer to copper but to metal in general, and it may then later have been transferred to copper in some countries when this metal entered common usage: "Hence none of these words can serve as evidence for dating Proto-IE".