The Hypogean fishes of China

China has 92 described species of hypogean (cave and artesian) fishes. That is nearly one third of all the described hypogean fish species (299), more than any other country. Of all Chinese hypogean fishes 56 species show troglomorphisms, i.e., adaptations that have been correlated to the hypogean environment such as reduction and/or loss of eyes, pigmentation, and the gas bladder. Additionally, two other characters seem to be unique to some Chinese hypogean species: presence of a horn-like structure and hyperdevelopment of the dorsal protuberance similar to a humpback. Despite the fact that the first written account of a cave fish was for species found in China in 1540 (Romero 2001; and Introduction to this special volume), almost all the new descriptions have taken place in the last 20 years mostly in papers written in Chinese and/or in journals of difficult access outside China. This paper summarizes all the knowledge we have on the hypogean fishes of China and puts them in context regarding all the hypogean fishes in the world.