"Another observation that needs to be pointed out is that a number of scholars are prepared to consider that the Bactria Margiana Archaeological Complex (BMAC), which will be discussed in the next chapter, is an Indo-Aryan culture. The horse has been evidenced in this culture in the form of representations in grave goods. However, no horse bones have been found despite the availability of a large number of animal bones. This again underscores the point that lack of horse bones does not equal the absence of horse. Nor, at least in the opinion of those who subscribe to the Indo-Aryan identification of the BMAC, does this lack equal the absence of Indo-Aryans. Therefore, anyone prepared to associate the BMAC culture with the Indo-Aryans cannot then turn around and reject such an identification for the Indus Valley on the grounds of lack of horse bones in the latter."
January 1, 1970
https://en.wikiquote.org/wiki/Bactria%E2%80%93Margiana_Archaeological_Complex