THE NATURAL HISTORY OF THE DOUCS AND SNUB-NOSED MONKEYS

Edited by N.G. Jablonski Singapore: World Scientific, 1998. 382 pages. ISBN 981-02-3131-8. Hardback: £44

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This volume of papers is primarily the outcome of a full-day symposium entitled "The biology of the snub-nosed langurs of China and Vietnam", held at the Bali IPS Congress on 7 August 1994, and to my knowledge, regrettably the only published proceedings from that Congress. The book contains especially invited additional chapters, mainly on doucs. It is divided into four parts - "Evolution and systematics", "Anatomy", "Ecology and Behaviour" (the largest section) and "Conservation". The authors include established Asian primatologists such as Nina Jablonski, Lois Lippold, and William Bleisch and newcomers such as Craig Kirkpatrick, Rameesh Boonratana, and Le Xuan Canh. Chinese researchers constitute more than two-thirds of the 35 authors. Two new Pygathrix roxellana subspecies, regrettably first scientifically named in the IPS Congress Abstracts receive a fuller description from Wang, Jang and Li.

Like geladas, the doucs and snub-nosed monkeys are remnants of a once more dominant adaptive radiation, and no understanding of the natural history of the Old World monkeys is complete without an appreciation of the significance of this now highly endangered group. Not only has their distribution contracted, but they also inhabit one of the most biologically and climatologically instructive, albeit scientifically neglected areas of the world. As high-profile animal they can supply much information about the ecology and physical history of their fascinating but rapidly disappearing environment, more readily than sympatric organisms whose scientific study has barely commenced. This book should therefore attract a much wider readership than the normal primate work.

This is not to say that the study of these monkeys is well advanced. Until now, knowledge of them was fragmentary and scattered, demanding diligent researches in order to create even the most meagre impression of their ecology. This book should be seen as an attempt to assimilate that knowledge, presenting the results of much-needed recent research, but barely bringing their study to the starting blocks, rather than forming a definitive overview. The sparsity of our knowledge is demonstrated by the description in 1997 of a new grey-shanked douc subspecies (arguably a new species) which is figured, but incorrectly identified, in the colour photograph on p.195.

Perhaps in an attempt to endow her taxonomic arrangement with more authority than it merits, Jablonski assumes the role of ringmaster as well as editor. However, her own papers are a triumph of form over content. Despite the huge table of unwieldy cladistic data she presents at the end of the chapter (an unfortunate characteristic of many of her papers), there is very little in them to support some of her taxonomic conclusions, which underpin her biogeographic interpretations. Jablonski is at pains to emphasise her conversion since 1994, from the view that the doucs and snub-nosed monkeys are monopyhyletic, almost apologising for the inclusion of the doucs in this book. The basis for this rejection, however, which follows the principle of total evidence, is unconvincing. At first sight, an analysis of 455 characters (we later learn that 130 of these are duplications owing to sexual dimorphism) from 540 specimens of 36 species appears impressive, but closer inspection dissipates this illusion. In one fell swoop a heady mixture of skull, postcranial, skin, and pelage characters are combined in an analysis with minimal attempt at weighting. This approach is analogous to planning an itinerary by map, without appreciating the distinctions between footpaths, bridleways, roads, railways and flightpaths. Jablonski's methodology has all the disadvantages, but probably none of the advantages of numerical taxonomy. In order to obtain a statistically valid sample size, potential intraspecific geographic variation is obscured by grouping specimens into preconceived demes. Important but geographically restricted, and therefore scientifically poorly represented, populations are often ignored or rashly merged with other populations. Pre-established taxonomic groupings are reinforced and unsuspected differences go undetected. The unwieldy diversity of characters analysed en masse leaves one suspecting that,were the specimens analysed in any random arrangement of groupings, one would conclude they were distinct taxa.

In her paper on the evolution of the doucs and snub-nosed monkeys, Jablonski's species sample size is not presented, and the possibility of misidentification ignored. The rationale behind the coding of skin coloration is incomprehensible and appears arbitrary. That her analysis suggests sister-taxa relationships between S. entellus and T. pileatus demonstrates its inability to discriminate between phyletic relationship and parallelism, as these species clearly represent the end-products of two independent stems of northward colobine dispersal from Sri Lanka and Java respectively, and are as widely separated as any species in the genus Semnopithecus (sensu lato).

From the taxonomic viewpoint, another disappointment is the rather poorly written chapter by Wang, Jang and Li. Not only does it achieve a particularly low standard of description and detail for what was intended to be the instigation of two new subspecies, but it also directly contradicts the brief, but unfortunately valid description which established these species in the IPS congress abstract. We were told in 1994 that the dorsal pelage of Pygathrix roxellana hubeiensis is grey brown, but in this book, we are assured that it is has pale golden-reddish dorsal pelage with dull-brown limbs. I know that Nina Jablonski tried during the editing process to resolve this discrepancy, but is it acceptable to publish so flawed a paper rather than delay until the authors produce an adequate description? Such a paper leads to confusion, and a lowering of confidence in the scientific merit of the entire book, which reflects somewhat unfairly on the other authors. Also unfortunate are the large number of typographical errors, particularly in evidence in Judith Caton's paper (whose otherwise intriguing analysis of stomach characters links Pygathrix with Nasalis and Rhinopithecus with Procolobus). These errors undermine confidence in the editor's own chapter with its long and uncheckable numerical data sets

I do not wish to be entirely negative, and there are many good points to mention. The book contains a valuable synthesis by Craig Kirkpatrick on the ecology of Rhinopithecus and Pygathrix, which includes a very useful appendix of weights and measures. Lois Lippold presents a much needed and overdue overview of douc ecology. Boonratana and Canh's chapter includes three wonderful colour photographs of their critically endangered study animal, P. avunculus. This short paper reflects the unfortunate scarcity of knowledge about this beautiful primate. William Bleisch contributes to three chapters, including a nutrient analysis of the leaves, both eaten and uneaten, by P. brelichi. The chapter on social organisation in P. roxellana shows that large aggregations such as one of 350 individuals, are actually comprised of one male troops, averaging twelve individuals, and all male bands with 4-7 individuals, which come together in temporary associations.

My overall impression of the book is that it is less than the sum of its parts, and at £44 I personally want more from it than it delivers. If the snub-nosed monkeys are your specialist area, then this is probably a "must have". However, the definitive book on this group still remains to be written - whether the monkeys concerned can survive for the time it will take to gather the research, is another, and urgent question.