A new perspective on Ungulate Taxonomy

Ungulate Taxonomy

A new perspective from Groves and Grubb (2011)

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.

Continue below to the updated taxonomy, or keep exploring this site:

Literature Cited

Groves, C., and P. Grubb. 2011. Ungulate Taxonomy. The John Hopkins University Press, Baltimore.

IUCN (International Union for Conservation of Nature and Natural Resources). 2010. IUCN Red List of Threatened Species. Version 2010.1. Available online at the IUCN Redlist website.

Wilson, D. E., and D. M. Reeder [editors]. 2005. Mammal Species of the World (3rd Edition). Johns Hopkins University Press, 2,142 pp. Available online at the Mammal Species of the World website.