Extreme environments, such as subterranean habitats, are suspected to be responsible for morphologically inseparable cryptic or sibling species and can bias biodiversity assessment. A DNA barcode is a short, standardized DNA sequence used for taxonomic purposes and has the potential to lessen the challenges presented by a biotic inventory. Here, we investigate the diversity of the genus
Leptonetela Kratochvíl, 1978 that is endemic to karst systems in Eurasia using DNA barcoding. We analyzed 624 specimens using one mitochondrial gene fragment (COI). The results show that DNA barcoding is an efficient and rapid species identification method in this genus. DNA barcoding gap and automatic barcode gap discovery (ABGD) analyses indicated the existence of 90 species, a result consistent with previous taxonomic hypotheses, and supported the existence of extreme male pedipalpal tibial spine and median apophysis polymorphism in
Leptonetela species, with direct implications for the taxonomy of the group and its diversity. Based on the molecular and morphological evidence, we delimit and diagnose 90
Leptonetela species, including the type species
Leptonetela kanellisi
(Deeleman-Reinhold, 1971). Forty-six of them are previously undescribed species.
Leptonetela tianxinensis (Tong & Li, 2008) comb. nov. is transferred from the genus
Leptoneta Simon, 1872; The genus
Guineta
Lin & Li, 2010 syn. nov. is a junior synonym of Leptonetela;
Leptonetela gigachela (Lin & Li, 2010) comb. nov. is transferred from
Guineta. The genus Sinoneta Lin & Li, 2010 syn. nov. is a junior synonym of
Leptonetela;
Leptonetela notabilis (Lin & Li, 2010) comb. nov. and
Leptonetela sexdigiti (Lin & Li, 2010) comb. nov. are transferred from
Sinoneta
;
Leptonetela sanchahe Wang & Li nom. nov. is proposed as a replacement name for
Sinoneta palmata
(Chen et al., 2010) because
Leptonetela palmata is a preoccupied name.
