The dorylaims are one of the most diverse and ecologically important nematode groups of soil and freshwater nematodes and have been the subject of much research. Jairajpuri & Ahmad (1992) recognised about 200 genera with 1700 species in the Dorylaimida. According to Andrássy (2009) the number of valid Dorylaimida genera had increased to 263 with over 2600 valid species, a substantial rate of increase. Not surprisngly, the group continues to accrue new species and genera from many different habitats and countries.
Of the many important publications on this group, mention must be made of the monographs by Thorne (1939), Jairajpuri & Ahmad (1992) and Andrássy (2009), these volumes usually focusing rather more on taxonomy and systematics than morphology, bionomics and biogeography. The present volume, prepared by Prof. Reyes Peña-Santiago, one of the foremost and most experienced experts in the group, redresses this balance, although also including a very useful, updated and comprehensive, systematic scheme for the group.
Much of the more recent interest in dorylaims has been related to their potential role as ecological markers or bio-indicators in soil, an area where their highly variable feeding habits and enormous variation in body form and size makes them particularly useful in assessing soil status or ‘health’ and other environmental variables. The fact that many species show a high sensitivity to heavy metals and various soil contaminants adds to their portfolio of attributes in this field.
Dorylaims display a great variety of lifestyles and are abundant, probably the most abundant, components in both soil and freshwater environments. Some are fungal feeders, whilst others are algivorous, omnivorous, predatory or obligate plant-parasites. As a result of this diverse feeding strategy, their morphology is, although clearly derived from a basic pattern, also highly variable, particularly in relation to the structure of the lip region and associated structures, such as the odontostyle and odontophore, but also in the highly variable pharynx, form of the genital tract in both sexes and body form, such as overall size and tail shape. Although many of the ‘classical’ genera and higher taxa are likely polyphyletic, molecular sequencing is beginning to shed light on the complex, not to mention confusing, relationships that often exist between morphological concepts and phylogeny. The fact remains, however, that many dorylaims lack molecular data and morphology remains a crucial diagnostic parameter. On a morphological level the dorylaims present a number of challenges to the tyro nematologist or general soil biologist. It is thus vitally important that researchers intending to study the group, for whatever purpose, are familiar with the often unique morphology of these fascinating creatures.
The focus of this volume by Reyes Peña-Santiago, therefore, is to present an account of the diverse morphology and bionomics within the group and thereby serve as a comprehensive introduction and handbook to the dorylaims. The book, of necessity, is well illustrated by carefully selected figures and microphotographs, many of which stem from the author’s own research conducted over several decades. Students of the group will find a wealth of information summarised within these pages and it should be essential reading for any aspiring dorylaimophile.
David J. Hunt
Emeritus Fellow, CABI
Egham, Surrey, TW20 9TY
UK
References
Andrássy, I. (2009). Free-living nematodes of Hungary, III (Nematoda errantia). In: Pedozoologica Hungarica, 5 (Series Editors: Csuzdi, C. & Mahunka, S.). Budapest, Hungary, Hungarian Natural History Museum and Systematic Zoology Research Group of the Hungarian Academy of Sciences.
Jairajpuri, M.S. & Ahmad, W. (1992). Dorylaimida. Free-living, predaceous and plant-parasitic nematodes. Leiden, The Netherlands, Brill.
Thorne, G. (1939). A monograph of the nematodes of the superfamily Dorylaimoidea. Capita Zoologica 8, 1-261.