Cavefish as biological models in the laboratory and in the wild

Cavefish have advanced to the forefront as excellent models for laboratory studies in developmental and evolutionary biology.The iconic Mexican characid,Astyanax mexicanus,which consists of a surface-dwelling morph and about 30 interfertile cave-dwelling morphs,has become a major contributor to behavior,sensory biology,trait evolution,and biomedicine(Jeffery,2020).There are about 200 scientifically-described cavefish species distributed in karst areas on most continents(Proudlove,2015).Similar to A.mexicanus,a small subset of other cavefish taxa coupled with related surface-dwelling species are now serving as additional laboratory models to address a variety of important biological problems.A prime example is the cyprinid genus Sinocycloceilus,which contains 75 closely related surface and cave species endemic to the karst massifs of southwestern China(Jiang et al.,2019,2023;Ma et al.,2019).Comparative studies of Chinese and Mexican cavefish can be used to address a host of questions concerning the convergence and divergence of cave related traits.In the future,other Chinese cavefish species,such as the cave loach,as well as the more recently discovered European cavefishes,are likely to join the current group of excellent laboratory models.This special issue of Zoological Research presents the results of current research on these diverse cavefish species.In addition to recent research using cavefish models in laboratory studies,this issue also covers new research on cavefish in the wild.