So what is a species anyway? A primatological perspective

Abstract

Since Darwin's time, the question “what a species” has provoked fierce disputes and a tremendous number of publications, from short opinion papers to thick volumes.1 The debates covered fundamental philosophical questions, such as: Do species exist at all independently of a human observer or are they just a construct of the human mind to categorize nature's organismic diversity and serve as a semantic tool in human communication about biodiversity?2–4 or: Are species natural kinds (classes) or individuals that are “born” by speciation, change in course of time, and finally “die” when they go extinct or diverge into new species?5–8 Also included was the problem of species as taxa (taxonomic) versus species as products of the speciation process (evolutionary).9 More pragmatic issues arose, such as: How can we reliably delineate and delimitate species?10, 11 The great interest in what a species is reflects the importance of “species” as fundamental units in most fields of biology, especially evolutionary biology, ecology, and conservation.2, 12–14

Identifying primate species: Themes and Perspectives

“…Almost all of the authors advocate and use the Phylogenetic Species Concept in their research, usually for practical reasons . Only one author advocates the use of Mayr's Biological Species Concept .…”

“…the authors vary in the specificity with which they described their approaches, both because of their diverse perspectives and the limited space they had available. Some describe relatively specific analytical criteria, while others emphasize the difficulty of the process and the many potential pitfalls involved in it . Most authors stress the importance of finding concordance among many different types of evidence, such as genetic differences, vocalizations, behavioral differences, and geographic isolation .…”

“…Some describe relatively specific analytical criteria, while others emphasize the difficulty of the process and the many potential pitfalls involved in it . Most authors stress the importance of finding concordance among many different types of evidence, such as genetic differences, vocalizations, behavioral differences, and geographic isolation . Likewise, virtually all of the contributors emphasize that the features distinguishing individual species vary from taxa to taxa, so that the features that delineate one group of primates are likely to be different from those that distinguish other taxa.…”

“…During the past decade, technological advances in genetics have greatly increased our understanding of hereditary material underlying the similarities and differences among extant primates, so that researchers can determine which aspects of the genome are unique to individual populations and which are shared. As the technology of genomic sequencing advances at a rapid pace, it seems likely that we will see increasing complexities that will have profound effects on our understanding of both the processes and the patterns involved in primate speciation, with corresponding changes in the way primate species are identified and classified …”

“…First, each author was asked “What is a species and are species important?” Not surprisingly, since they agreed to contribute to this exercise, virtually all of the authors felt that species are important as the basic unit of animal life and the one used for measuring diversity in both the past and the present, despite the difficulties in reaching any consensus about how to define and identify them Nevertheless, some authors suggest that understanding the processes of genetic diversification between and among populations of extant primates is perhaps a more important goal than the ability to assign taxonomic levels or names. Surprisingly, in light of much criticism of taxonomic inflation, the authors most involved in primate conservation argue that, from a conservation perspective, the unit recognized as “species” should not have greater significance than any other taxonomic unit, such a subspecies, in considerations of taxonomic diversity that needs to be preserved.…”