"The Borneo Suckers," by Tan Heok Hui (2006)

Natural History Publications (Borneo), Kota Kinabalu, 245 pp., 18 colour plates, 130 monochrome figures, 15 maps. ISBN 983-812-105-3.

THE BORNEO SUCKERS.
Beautiful and charismatic fish always have had an attraction for taxonomists. And to the public as well. However, many non-ichthyologists do not realize that the taxonomy of many of the most colorful fishes aquarists and biologists fancy is often very difficult. The resolution of the numerous systematic problems associated with such fish requires a keen eye, a good appreciation of their taxonomic history, extensive field work, the need to acquire numerous specimens, a necessity to work with fresh and live material, and a good understanding of their biology and habits. When these “ideals” can come together, we can expect a work of great significance. The present book by H. H. Tan is one such “masterpiece”.

Sucker loaches or gastromyzontine loaches are strange animals to say the least. They neither look nor behave like fish – they are more likes tadpoles in many respects. Their flattened body form is superbly adapted to life in pristine water torrents, and they feed on the algae and riparian insects associated with these habitats. And they are a Bornean phenomenon – the three genera of these loaches occur only on the great island of Borneo. Despite their stringent water requirements and fussy food requirements, they are quite popular in the aquarium trade – they are strange fish with unusual habits and colorful patterns.

In the eight years it has taken to finish this study and get it to print, Tan has visited numerous museums where the old material is held, worked with many colleagues in Sarawak, Sabah, Kalimantan and Brunei to get fresh material, and benefited from the help provided by many professionals. In the process, he has cleared up most of the “sticky” problems long associated with these fishes. The colour patterns, so valuable in their taxonomy, are identified using fresh material, and correlated with new morphological characters. The identities of several supposedly wide ranging species (e.g. G. borneensis) is clarified and restricted, and in the process, a good number of new species are described. Tan recognizes three genera, Gastromyzon, Neogastromyzon and Hypergastromyzon, with a total of 41 species. Of these, 19 are described as new by Tan in this book. However, Tan had already described nine species in preceding years – so in total, almost 70% of the known taxa were described through his research activities over the years.

The book is organized into seven main chapters: Introduction, Biogeographical Observations, Ecological Observations, Economic Value, Bornean Endemic Genera and Species, Material and Methods, and Taxonomy. Many of the biogeographical and ecological observations are new from his study – stemming from the extensive field work done and analysis of datasets. The many species are treated systematically in 11 species groups, and all are described and figured in detail. One of the most striking aspects of the book must surely be the large number of color plates provided – 18 – and 29 species are illustrated in full colour – many for the first time. Worthy of further study is their conservation – Tan notes that of the 41 species known, 19 have very restricted distributions, being confined to single river basins or the like. This makes them highly vulnerable to human activities – and as their presence is closely associated with the water quality, this is surely a concern.

This is a book all ichthyologists, aquarists and lovers of Southeast Asian animals will love to have on their shelves. As much as H. H. Tan must be congratulated on getting this book out, kudos must also go to the chief editor of the Natural History Publications series - Chan Chew Lun – who has published many excellent books on Bornean biodiversity and culture, and in the process, opened the eyes of the world to the wonders of the region.

Peter K. L. Ng
Department of Biological Sciences
National University of Singapore
Kent Ridge, Singapore 119260, Republic of Singapore
Email: dbsngkl@nus.edu.sg

First published in The Raffles Bulletin of Zoology Vol. 53(2): 289 on 31 Dec 2005