Complex sentence: A lineage-bonded society is, by population, the smallest classification of acephalous society, because beyond a certain size threshold, claims of common lineage become untenable, and the social ties that come from those claims destabilize.
Split into simpler sentences: A lineage-bonded society is, by population, the smallest classification of acephalous society. Beyond a certain size threshold, claims of common lineage become untenable, and the social ties resulting from those claims destabilize.