Two IE phylogenies, three PIE migrations, and four kinds of steppe pastoralism

This paper defends and elaborates a Pontic-Caspian steppe homeland for PIE dated broadly between 4500-2500 bc. First I criticize the Bouckaert et al. phylogeny, rooted in Anatolia, published in Science in August 2012. Then I describe archaeological evidence for three migrations from the Pontic-Caspian steppes into neighboring regions, dated to 4500-2500 bc, that parallel the sequence and direction of movements for the first three branches in the Ringe phylogeny (Ringe, Warnow and Taylor 2002) of the Indo-European languages: 1. Anatolian, 2. Tocharian, and 3. a complex split that separated Italic, Celtic, and perhaps Germanic (Germanic could be rooted in two places in their phylogeny). Each of the migrations I described is suggested by purely archaeological evidence, unconnected with any hypothesis about language. They are dated about 4400-4200 bc for branch 1, 3300-2800 bc for 2, and 3000-2800 bc for 3. These three apparent prehistoric movements out of the Pontic-Caspian steppes match the directions expected for the first three splits in the Ringe phylogeny, and the directions of later movements are plausible given the Ringe sequence and the known later locations of the daughter branches. The parallel between the archaeological sequence and the linguistic sequence, each sequence derived from independent data, is argued to add archaeological plausibility to the hypothesis of the Pontic-Caspian homeland for PIE. In addition, recent archaeological research on steppe economies and diets shows that it is misleading to regard "steppe pastoralism" as a single undifferentiated economic category. I suggest that we can link the three earliest periods of outward migration from the Pontic-Caspian steppes with particular kinds of pastoral economy in the steppes. I provided a brief characterization of four different kinds of steppe pastoralism relevant to Indo-European migrations.