Taxonomy, ecology and conservation of the cave-dwelling spider Histopona palaeolithica, with the description of H. petrovi sp. nov. (Araneae: Agelenidae)

The spider genus Histopona Thorell, 1869 (Araneae: Agelenidae) includes several species that exhibit a preference for subterranean conditions, being occasionally or exclusively found in caves, crevices and similar habitats. Within the genus, the species displaying the highest level of subterranean adaptation is possibly H. palaeolithica (Brignoli, 1971). This species was described based on a female collected in 1967 in a cave on the Western Ligurian shore (Italy), but had never been recorded thereafter. Our recent biospeleological surveys at the type locality failed to recover the species, possibly because the cave has been impacted by the expansion works of a large quarry. However, we found a new population in a cave opening a few hundred meters away from the type locality. As a result of this finding, we provide the first description of the male, as well as a re-description of the female. We also describe a new species of Histopona based on a female specimen that was collected in a cave in Montenegro, and was previously attributed to H. palaeolithica. In light of the rarity of these specialized stenoendemic species, we provide general information on their ecology and conservation status, as well as information useful for assessing their extinction risk based on International Union for Conservation of Nature (IUCN) guidelines.