The Rise of Placental Mammals: Origins and Relationships of the Major Extant Clades

Kenneth D. Rose & J. David Archibald, Eds. (2005)

The John Hopkins University Press: ISBN 0-8018-8022-X (hardback) £63.50

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This substantial multi-author volume consists primarily of series of reviews of the early fossil record for the major mammalian groups and as such ought to be required reading for anyone interested in Primate origins. However I say ‘ought to be’ quite guardedly because this is very much a reference book and it would be very difficult to persuade any but the keenest undergraduates to read through it. However for more advanced students there is a lot of important comparative information here and it also provides considerable insight into the current issues and debates within mammalian palaeontology. In particular whilst most primatologists currently subscribe to the view that in the absence of any compelling fossil evidence to the contrary, the order Primates originated sometime in the Paleocene, the prevailing view amongst the more general mammalian palaeontologists seems to be that most modern mammalian orders, Primates included, had a Cretaceous origin. And for those of us brought up on the cosy, gradistic classification schemes of Fleagle and others, there is a whole new set of largely unpronoucable cladistic superorder groupings to get to grips with although mercifully most of the order names seem to have been retained. I am not looking forward to having to talk about Euarchontoglires to my students! Of course most of this new cladistic analysis is based on various molecular techniques and there are of course some dissenting voices, however the general level of acceptance is surprisingly high - perhaps due to some careful author selections by the editors.

The book starts with obligatory overview of mammals, a general introduction of what is to come and provides some taxonomic scene setting. It is followed by a chapter detailing Gaylord-Simpson's work on mammals which, whilst interesting, feels a little out of place given the rather hard-hitting nature of the rest of the book. Chapters 3 and 4 are where it starts to get interesting since they detail the anatomical and molecular evidence for early mammalian phylogeny. These are both detailed, factual chapters and surprisingly are essentially in agreement reflecting the complementary rather than conflicting nature of the phylogenetic information available from each source.

The rest of the book details the origins of particular mammalian orders (or groups of orders) on a chapter by chapter basis: Insectivorans; Macroscelidea and Tubulidenta; Paenungulata; Xenarthra and Pholidota; Euarchonta; Glires; Chiroptera; Carnivora; Perissodactyla; Artiodactyla; Cetacea. The format is dense and factual with each chapter reviewing the origin of the grouping; the diagnostic anatomical features; major subdivisions and their diagnosis; key early fossil taxa; temporal and geographical origins; along with general notes on features and phylogeny. There are some fine fossil photographs although most of the anatomical information is portrayed by representative line drawings. It is certainly not a beginners text and there is no glossary for any unfamiliar terms but it is all well referenced so entirely appropriate for its target audience.

Of particular interest to primatologists is Chapter 9, entitled Euarchonta (Dermoptera, Scandentia, Primates) by Silcox, Bloch, Sargis and Boyer. This grouping was originally proposed by Gregory in 1910 and included Chiroptera but has had a rather chequered career. However the current version without the bats is strongly supported by molecular evidence and looks like it is here to stay. The chapter starts by summarising (hypothesised) anatomical features diagnostic of the group as a whole and then proceeds through the 3 orders providing a brief description of the fossil evidence (mainly Eocene in the case of Primates). There then follows an extended section looking at various Palaeocene taxa that may fit within this grouping. This includes the Plesiadapiformes that once again get grouped in Primates although not within the semiorder Euprimates that is limited to the Adapidae, Omomyidae and the modern families. The time of origin is discussed with a clear Cretaceous origin indicated by molecular evidence but with little or no support from fossils. The place of origin is reported as similarly ambiguous but with some nice maps demonstrating the different possibilities. Altogether this is a worthwhile chapter, although a little short compared to some of the others in the book.

So, should you buy the book? Well it is quite good value at just over £60 for a large hardback volume, and certainly if you are interested in the position of Primates in a broader mammalian phylogenetic context then it is extremely useful. However its depth of coverage of primate specific material is quite limited: Euarchonta gets 18 pages and perhaps half of that is on Primates. However your library should definitely get a copy. There are useful chapters on phylogeny and it provides good coverage of some of the major debates in mammalian palaeontology such as the origins and affinities of the Cetacea and Chiroptera which make interesting reading. It will provide useful initial reference for student essays and projects for a few years until new fossils and better molecular data renders it obsolete.

BILL SELLERS

Faculty of Life Science, University of Manchester