Balkanopetalum rhodopinum Verhoeff, 1937

Figs 4­6.

Type locality: ‘neue Höhle bei Pestera im Rhodope­Gebirge’ .

Literature records: Novata Peshtera Cave near Peshtera (Verhoeff, 1937: 97; Lang, 1958: 39; Strasser, 1966: 349); Yubileina Cave near Peshtera (Strasser, 1975: 74). The record from Garvanyovitsa Cave near Turen (Strasser, 1969: 145) was based on juveniles only and is probably erroneous, see also notes under beskovi).

Material examined (all from Bulgaria): 1 M, 2FF, Novata Peshtera Cave near Peshtera, 01.12.1991, B. Petrov leg.; 1 M, 1F, same locality, June, 1992, D. Dimitrov leg. ; 2 MM, 2 FF, 2 juv., same locality, 30.03.1996, B. Petrov leg.; 2 FF, same locality, 15.01.2000, clay, rotten log, B. Petrov leg.; 1 M, 1F, 2 juv., Yubileina Cave near Peshtera, 09.04.1974, P. Beron leg. ; 2 MM (1M, ZMUC), same locality, clay, 28.06.2000, B. Petrov, P. Nikolov leg.; several specimens, same locality, 10.05.2002, B. Petrov leg.

Diagnosis. This species is easily distinguished from its congeners by the very long (horn­like), subdistal process on the femoroid, pointing upward and parallel to the main femoroid stem. This process lacks a homologue in the other species (with the possible exception of the tiny basal tooth in beskovi). The anterior gonocoxal process is apically divided into two small tines. The posterior coxal process is curved apically. The distal femoroidal process is straight and slender, perpendicular to the main femoroidal axis and almost parallel to the posterior coxal process, both pointing towards the subdistal process. The ovoid plate is moderately long and evenly rounded. The solenomerite is bifid (Figs 4, 5). The prefemur of the male 7th leg­pair is moderately swollen mesally (Fig. 6). These characters, together with the higher number of anterior setae on the collum (8, instead of 4), the smaller body size (length 44­48 mm, diameter 2 mm) and generally paler (pale brown­yellowish) colour well distinguish rhodopinum from its congeners.

Chaetotaxy. See Table 2.

Notes. B. rhodopinum has very limited distribution, so far having been found only in two karst caves in the region of Peshtera. There are several unexplored caves in same region, and a more profound study will probably result in its discovery there. A connection between the cave fauna of the Velingrad karst region and the Peshtera one seems to exist, sharing same cave inhabitants. In Yubileina cave rhodopinum coexists with the troglobites Lithobius lakatnicensis Verhoeff, 1926 and L. stygius Latzel, 1880 (Chilopoda), in Novata Peshtera Cave with L. lakatnicensis and another troglobite, Bulgaronethes haplophthalmoides Vandel, 1967 (Isopoda) .