Using extant morphological variation to understand fossil relationships: A cautionary tale

Recent studies of variation in living monkeys, apes, and humans have produced a number of insights that are pertinent to how we evaluate relationships among our fossil human ancestors. Here I summarize four such insights. I then use a fossil hominid example to illustrate how our understanding of variation can alter our interpretation of the past. Results show that our assessments of the relationships among fossil hominids can differ depending on which extant model of variation is used as a variation ‘yardstick.’ Additionally, our interpretations of these relationships can be swayed considerably by how we evaluate significance