Abstract

Despite the iconic roles of coelacanths, cycads, tadpole shrimps, and tuataras as taxa that demonstrate a pattern of morphological stability over geological time, their status as living fossils is contested. We responded to these controversies with a recommendation to rethink the function of the living fossil concept. Concepts in science do useful work beyond categorizing particular items and we argued that the diverse and sometimes conflicting criteria associated with categorizing items as living fossils represent a complex problem space associated with answering a range of questions related to prolonged evolutionary stasis. Turner defends the living concept against a variety of recent skeptics, but his criticism of our approach relies on a misreading of our main argument. This misreading is instructive because it brings into view the value of three central themes for rethinking the living fossil concept—the function of concepts in biology outside of categorization, the methodological importance of distinguishing parts and wholes in conceptualizing evolutionary phenomena, and articulating diverse explanatory goals associated with these phenomena.