The genus Histopona Thorell (Araneae, Agelenidae) with description of two new cave-dwelling species

<p>A diagnosis of the genus Histopona Thorell is presented. In the past, ambiguous definitions of the genus have been the origin of&nbsp;some taxonomic confusion. All species hitherto included in the genus Roeweriana Kratochvil are here transferred to Histopona.&nbsp;Male and female of H. egonpretneri n. sp. (cave in Mt. Velebit, Croatia) and isolata n.sp. (cave on Crete) are described and&nbsp;pictured.&nbsp;Histopona laeta (Kulczynski) and&nbsp;H. debilis Thorell are synonymized with H. torpida and H. laeta var. paganettii&nbsp;(Nosek) with H. conveniens Kulczynski. It is argued that differences between Roeweriana and Histopona were based mainly on&nbsp;reduction of eye size and pigmentation in the former. According to modern views loss of eye, in many spider species appears to be&nbsp;a minor, fairly easily accomplished adaptation with little phylogenetic weight and this character alone cannot be accepted as a&nbsp;ground for the separation of genera.<br />
The genus Histopona here conceived comprises at present 16 species; 11 inhabit hypogean habitats in limited ranges in&nbsp;southeastern Europe; several are known from one cave only. Histopona torpida is a purely epigean species, distributed over most&nbsp;of Europe, the other epigean species occupy smaller, partly overlapping ranges. A group of closely related species in caves in the&nbsp;southwestern Balkan Peninsula (group myops) is troglobitic ; no eyeless species are known at present.</p>