John Hopkins University Press, Baltimore. ISBN-13 978-1-4214-0093-8 und ISBN-10 1-4214-0093-6.
A group of special interest to mammalogists, taxonomists, and systemicists, ungulates have proven difficult to classify. This comprehensive review of the taxonomic relationships of artiodactyls and perissodactyls brings forth new evidence in order to propose a theory of ungulate taxonomy.
With this straightforward volume, Colin Groves and the late Peter Grubb cut through previous assumptions to define ungulate genera, species, and subspecies. The species-by-species accounts incorporate new molecular, cytogenetic, and morphological data, as well as the authors’ own observations and measurements. The authors include references and supporting arguments for new classifications.
A starting point for further research, this book is sure to be discussed and hotly debated in the mammalogical community. A well-reasoned synthesis, Ungulate Taxonomy will be a defining volume for years to come.
Taxonomy (the study of classification) is a constantly-evolving field. Every year, changes to the "standard" list of ungulates (covering approximately 250 species) are proposed as new physical and genetic evidence becomes available: renaming subspecies as distinct species, separating (or uniting) genera, or naming species new to science. Most taxonomic changes are rather restricted in scale (usually reorganizing a species or genus). Rarely, however, entire orders are reviewed and revised: the ENTIRE scope of hoofed mammals receives such a treatment in Ungulate Taxonomy (Groves and Grubb, 2011).
Ungulate Taxonomy turns the classification of hoofed mammals on its head. Whereas traditional species lists rely on the Biological Species Concept (which differentiates species on the basis of "reproductive isolation", the lack of interbreeding in nature), Groves and Grubb have applied the Phylogenetic Species Concept (which separates species on the basis of "fixed heritable differences": measureable characters that are consistently different between taxa). This change in approach has had major implication on the number of species: Groves and Grubb recognize over 450 distinct ungulates. Simultaneously, however, the recognition of subspecies has sharply declined: under the Phylogenetic Species Concept, populations that can be differentiated are listed as separate species; those which cannot be are grouped as a single taxon.
The new approach to ungulate classification is presented below alongside the traditional species list (note that species fact sheets are accessible from the Ungulates of the World page). Such a radical departure from tradition often encounters great resistance, but the application of the Phylogenetic Species Concept to ungulate taxa is not brand-new: it is generally well-accepted for taxa like babirusas, chevrotains, and musk deer.