A brief history of a hot spot of biospeleology, in the light of the biogeographical distribution of subterranean fauna in Apulia (SE Italy)

In Apulia (SE Italy), one of the most remarkable biospeleological areas in Italy, Salento (its southernmost portion) is in turn a very interesting sector, showing the highest number of troglobionts and endemic species. Following a brief description of the main characters of the biogeography of Italy, with particular regard to Apulia, the present paper deals with the main biospeleological outcomes from the cave Lu Bissu (The abyss; number 141 in the Regional Inventory of Caves), located in the territory of Castro (Lecce province). Notwithstanding its quite limited size and depth, the cave is one of the most remarkable example in Apulia as regards biospeleology: in fact, Lu Bissu hosts 15 troglobiont species (10 aquatics and 5 terrestrials). They represent 35 % of the whole hypogean fauna in Apulia, which means that one third of the Apulian species are present in this cave. After a description of the main geological and morphological characters of the cavity, the 15 species are listed and briefly described. Eventually, some considerations on the necessity to protect the cave are presented, aimed at safeguarding the important biological heritage it hosts.