The systematics of the genera Gastromyzon, Hypergastromyzon and Neogastromyzon of the family Balitoridae, all of which are endemic to Borneo, are revised. These genera possess an increased number and enlarged size in the pectoral and pelvic fins, fused pelvic fins and dorso-ventrally flattened bodies. They live in the headwater and hillstreams, typically in fast-flowing water over a rocky substratum. All type material of the 21 known species of Gastromyzon is re-described, with another 15 new species described. The genus Gastromyzon, now with 36 species, is divided into 11 artificial species groups: Gastromyzon borneensis group, G. punctulatus group, G. fasciatus group, G. contractus group, G. ctenocephalus group, G. lepidogaster group, G. ridens group, G. danumensis group, G. pariclavis group, G. ocellatus group and G. auronigrus group. The status of G. borneensis and G. lepidogaster is resolved with fresh topotypical material. The taxonomy of G. borneensis, G. danumensis, G. fasciatus, G. lepidogaster and G. punctulatus is clarified with fresh material and material from a wider distribution. A lectotype is designated for G. monticola. The life colouration of 26 species of Gastromyzon is illustrated, together with line drawings of juveniles of 15 species.
The genus Neogastromyzon is also revised and the identities of the two known species clarified and another four new species are described. All type material is illustrated, with life colouration of 3 species. A brief diagnosis of Hypergastromyzon is also included. An artificial key is provided for all species of Gastromyzon, Hypergastromyzon and Neogastromyzon. The biogeographical, ecological observations and biology of these balitorids are compiled and presented.
INTRODUCTION
Exploration in Borneo and fish reports
BIOGEOGRAPHICAL OBSERVATIONS
Distribution of Gastromyzon, Neogastromyzon and Hypergastromyzon in Borneo
Patterns
Species restricted to single basins
Biogeographic patterns
Gastromyzon borneensis group of northern Borneo
Gastromyzon lepidogaster group
Cryptospecies and Species pairs
ECOLOGICAL OBSERVATIONS
Compilation of observations
Observations on locomotion
Observations on diet
Observations on reproductive characters
ECONOMIC VALUE
Aquarium fish trade
BORNEAN ENDEMIC FISH GENERA AND SPECIES
Food fish use (local recipes)
Vernacular names
Localities in Borneo
Sabah localities
Brunei localities
Sarawak localities
Kalimantan Barat localities
Kalimantan Tengah localities
Kalimantan Timur localities
MATERIAL AND METHODS
Material
Methods
TAXONOMY
Key to Gastromyzon, Hypergastromyzon and Neogastromyzon
Gastromyzon Günther, 1874
Species groups
Gastromyzon borneensis group
Gastromyzon borneensis Günther, 1874
Gastromyzon monticola (Vailiant, 1889)
Gastromyzon ornaticauda Tan & Martin-Smith, 1998
Gastromyzon cranbrooki Tan & Zohrah, 2006
Gastromyzon cornusaccus, new species
Gastromyzon extrorsus, new species
Gastromyzon introrsus, new species
Gastronyzon bario, new species
Gastromyzon punctulatus group
Gastromyzon punctulatus Inger & Chin, 1961
Gastromyzon aeroides, Tan & Zohrah, 2006
Gastromyzon katibasensis, Leh & Chai, 2003
Gastromyzon fasciatus group
Gastromyzon fasciatus Inger & Chin, 1961
Gastromyzon praestans, new species
Gastromyzon contractus group
Gastromyzon contractus Roberts, 1982
Gastromyzon megalepis Roberts, 1982
Gastromyzon umbrus, new species
Gastromyzon ctenocephalus group
Gastromyzon ctenocephalus Roberts, 1982
Gastromyzon scitulus Tan & Leh, 2006
Gastromyzon lepidogaster group
Gastromyzon lepidogaster Roberts, 1982
Gastromyzon psiloetron, new species
Gastromyzon ridens group
Gastromyzon ridens Roberts, 1982
Gastromyzon crenastus Tan & Leh, 2006
Gastromyzon stellatus, new species
Gastromyzon zebrinus, new species
Gastromyzon danumensis group
Gastromyzon danumensis Chin & Inger, 1989
Gastromyzon aequabilis, new species
Gastromyzon ingeri, new species
Gastromyzon pariclavis group
Gastromyzon pariclavis Tan & Martin-Smith, 1998
Gastromyzon embalohensis Rachmatika, 1998
Gastromyzon venustus Tan & Zohrah, 2006
Gastromyzon spectabilis, new species
Gastromyzon russulus, new species
Gastromyzon viriosus, new species
Gastromyzon ocellatus group
Gastromyzon ocellatus Tan & Ng, 2004
Gastromyzon farragus Tan & Leh, 2006
Gastromyzon auronigrus group
Gastromyzon auronigrus, new species
Neogastromyzon Popta, 1905
Neogastromyzon nieuwenhuisii group
Neogastromyzon nieuwenhuisii Popta, 1905
Neogastromyzon pauciradiatus (Inger & Chin, 1961)
Neogastromyzon crassiobex, new species
Neogastromyzon chini, new species
Neogastromyzon kottelati, new species
Neogastromyzon brunei, new species
INCERTA SEDIS
Neogastromyzon sp. 'Baram’
Hypergastromyzon Roberts, 1989
Hypergastromyzon humilis Roberts, 1989
Hypergastromyzon eubranchus Roberts, 1991
Literature cited
Acknowledgements
Plates
Index