Subterranean terrestrial isopods from southern China and Southeast Asia: state of the art and new findings

Until few years ago very little was known about terrestrial isopods inhabiting caves in southern China. Up to date, 14 species of terrestrial isopods have been recorded from caves in Yunnan, Guizhou, Guangxi and Guangdong, most of them being either trogloxenous or troglophilic. Recent investigations in caves of Guizhou, Guangxi and Guangdong have revealed the presence of several other new species in the families Styloniscidae and Armadillidae, many of which are endemics and can be regarded as real troglobionts. In particular the styloniscid genus Trogloniscus (new replacement name for Sinoniscus) includes five species, two of which are strictly aquatic but certainly derived from terrestrial forms, as demonstrated by the water conducting system still present in the pereopods. In the family Styloniscidae only another species from Thailand (Thailandoniscus annae) was previously known to occur in subterranean waters. In the family Armadillidae one new species of Spherillo, four new species of Dryadillo and a new genus and species, all of which are either microphthalmic or anophthalmic, have been recognised. The knowledge on cave isopods from Southeast Asia is very poor due to little investigations. At present 27 species have been recorded, most of which are trogloxenous, with the sole exception of the troglobiotic T. annae from Thailand, a species of Burmoniscus from Malaysia, and one of Dryadillo from Vietnam.