Ungulate Taxonomy
Ungulate Taxonomy by and . Baltimore : Johns Hopkins University Press , 2011 . ix + 317 pp. Hardback. ISBN-13 : 978-1-4214-0093-8 ; ISBN-10 : 1-4214-0093-6 . £52.00 .
In this book two experienced morphological systematists set out a classification of ungulate mammals (Perissodactyla and Artiodactyla). They give an account of all living species with descriptions, tables of measurements and characteristics, and many discussions of particular problems. The book does not go very far into the history and authorship of the names, a subject that has interested both authors in the past. Nor is it a checklist of synonyms, nor does it have any illustrations. What remains is a well-presented thorough statement of the position Groves and Grubb have reached on ungulate taxonomy.
The introductory chapter sets out the authors’ views on a number of relevant questions, including the contentious one of why they follow the Phylogenetic Species Concept. Under this concept a species is ‘the smallest population or aggregation of populations which has fixed heritable differences from other such populations or aggregations’. According to the older Biological Species Concept it is ‘a group of interbreeding natural populations reproductively isolated from other such groups’. The PSC procedure of finding one or more unique characters and then calling the animals involved a species is more objective than guessing how far a sample of museum specimens corresponds to a species in nature. It is obviously a procedure suited to database analyses and to dealing with animals taxonomically and temporally remote from ourselves such as, say, Palaeozoic brachiopods. In the background of the two Concepts is the well-known ‘selfish gene’ phenomenon – genotypes evolve down the generations, but are housed in phenotypes which have to face the onslaught of natural selection. The paths of interaction between genotypes and phenotypes are intricate and hence discrepancies arise between the molecular-level classification of genotypes and that based on the visible characters of phenotypes. Experience has shown that using the PSC leads to more species being listed than are apparent via the BSC, and this suits Groves and Grubb's outlook on taxonomy. They believe that the era of simplified mammal classification initiated by the Ellerman and Morrison-Scott checklists of the 1950s is over, and they name 27 species in Cervus for example, even though it is only one of six genera in their Tribe Cervini.
Groves and Grubb state that one or more characters in a species have to be non-overlapping with other species. This is an understandable concept when dealing with, say, the bases on DNA chains, but less so in the case of, say, coat colours. Phrases like ‘top of the head reddish, and preorbital marks sometimes faint’ don't read as though they are going to be recognisably non-overlapping in closely-related species. It looks as if we shall be obliged to distinguish carefully between diagnostic and descriptive characters. Or do we say that the molecular characteristics of the genotype reveal relationships while the morphology of the phenotype provides ‘diagnoses’ which may not always differentiate the species?
The book follows the ruling of the International Commission on Zoological Nomenclature for usage of names founded for wild species with domestic derivatives and explains sympathetically on page 8 how Grubb earlier took an unfortunate and regretted decision on this. The brief history of the taxonomy of ungulates in the introduction is most illuminating on the activities and mental approach of several prominent workers in the late 19th and early 20th centuries. The only serious fault I found was the absence of a key to the abbreviations of the measurements used in the tables. Maps of species’ ranges would have helped readers, but would have expanded the size and cost of the book to an impossible degree and delayed its appearance.
It is sad to note that Peter Grubb's life was cut short in December 2006, and that this book has to carry an In Memoriam notice by his co-author and long-term friend. I too knew him and enjoyed and profited from our occasional conversations. Five years and more later it is good that I can emphasize the value and comprehensiveness of Ungulate Taxonomy. It will become a reference base for future studies and it is a pleasant book to handle.
