Cavefishes: concept, diversity and research progress
洞穴鱼类:概念、多样性及研究进展

Cavefishes, or hypogean fishes, are a distinctive group of freshwater fishes. Their life histories unseverably bind them to a cave or underground water body. Some of them, termed troglobites, have specific characteristics adapting them to subterranean life. Other hypogean fishes, the troglophiles, do not possess such specialized characteristics. There are 107 typical troglobite fish species known in the world. Of these, Cypriniformes and Siluriformes have the most troglobite fish species, accounting for 49.5% and 24.3% of the total, respectively. At the family level, Cyprinidae and Balitoridae have the richest species diversity of troglobite fishes. Hypogean fishes are predominantly distributed in southeastern Asia, and central and south- ern America, where 75.0% are found. In China, rich species diversity occurs in only a few genera, namely Sinocyclocheilus and Triplophysa, characterized by narrow distributions, intense speciation, and small popu- lation size. Research on cavefish is a cross-disciplinary subject involving systematics, ecology, physiology, and conservation biology. At present, the study mainly focuses on evolution. A brief overview of progress around the globe in cavefish research is given, accompanied by an in-depth analysis of the still far-from-complete contributions of Chinese hypogean ichthyofauna studies to this field.