A new species of Eupolybothrus Verhoeff, 1907 discovered in caves of Velebit Mountain in Croatia is described. E. liburnicussp. n. exhibits a few morphological differences from its most similar congeners, all of which are attributed to the subgenus Schizopolybothrus Verhoeff, 1934, and two approaches to species delimitation using the COI barcode region identify it as distinct from the closely allied E. cavernicolus Stoev & Komerički, 2013. E. spiniger (Latzel, 1888) is redescribed and a lectotype is designated for it as well as E. caesar (Verhoeff, 1899) to stabilize their respective taxonomic status. The subspecies E. acherontis wardaranus Verhoeff, 1937, previously suspected to be a synonym of E. caesar (Verhoeff, 1899), is redescribed and its taxonomy revised after the study of type material whereas the identity of E. acherontis (Verhoeff, 1900) described from a female from southwest Trebinje (Bosnia and Herzegovina) remains unknown. Type material of E. stygis (Folkmanova, 1940) is confirmed to be lost and future designation of neotypes from topotypic specimens is necessary to stabilize its taxonomy. The importance of setal arrangement on the intermediate and 14th tergites and the sexual modifications on the male 15th prefemur for species identification is discussed in the light of present findings, and a review of the species of E. (Schizopolybothrus) that display these traits is also provided.
Keywords: Biospeleology; COI barcoding; Eupolybothrus; SEM; Velebit Mountain; new species.