Let’s talk about species, baby! Taxonomy and species concepts in the context of Homo luzonensis

Abstract

Classifying an individual into a species is one of the first steps to better understand not only the individual in question, but also their evolutionary history and relationships. However, designating individuals into species can be a difficult process. It is particularly difficult in the field of paleoanthropology, where species designations must be made using only skeletal remains. A recent publication announced the reported discovery of a new hominin species, Homo luzonensis, from remains found at Callao Cave in the Philippines. However, this new species consists of only 13 skeletal specimens from three individuals. With such a small sample size, do the Callao Cave remains represent enough evidence to be called a separate species? In order to explore this question, I examine several species concepts and how they can and have been applied to fossil hominin species. I also utilise several comparable and recently discovered hominin taxa as case studies. The results of these analyses indicate that while the remains from Callao Cave can be designated as a new species, the low specimen count and lack of DNA evidence means that future criticism of this designation is likely. In addition, these cases studies highlight structural and human factors—such as pressure to publish and arguments over types of evidence—which influence the species designation process.