Hydrobiologia 437: 235–239, 2000. © 2000 Kluwer Academic Publishers. Printed in the Netherlands. 235 Parastenocaris andreji n. sp. (Crustacea; Copepoda) – the first record of the genus in Slovenia (SE Europe) Anton Brancelj National Institute of Biology; Veˇ cna pot 111, 1000 Ljubljana, Slovenia E-mail: anton.brancelj@uni-lj.si Received 13 December 1999; accepted 21 August 2000 Key words: Harpacticoida, ground water, interstitial, taxonomy, Slovenia Abstract Parastenocaris andreji n. sp. was found in ground water in a northwestern part of Slovenia (southern part of Central Europe). Two adult females of the new species were filtered out of 20 000 l of water during examination of an aquifer for water supply. The bore well was 10 m deep. The aquifer is fed by rainwater and probably only occasionally from a nearby alpine river Sava. The new species differs markedly from other known species of the genus by shape and armature of furcal rami, very long and slim maxillae and some characters on endopodites P2–P5. The closest related species are probably Parastenocaris nolli Kiefer, 1938 with subspecies P. nolli alpina Kiefer, 1960, P. gertrudae Kiefer, 1968 and P. austriaca Kiefer, 1976. Introduction The genus Parastenocaris is a widely distributed genus in Europe (Kiefer, 1978). More than 50 spe- cies have been described in Europe (Petkovski, 1959; Rouch, 1988, 1992; Janetzky et al., 1996; Karanovic & Bobic, 1998). Members of the genus are restric- ted to ground water along rivers (interstitial water), to aquifers in alluvial plains and also common in small basins on the walls filled with dripping water in caves (Petkovski, 1959; Karanovic & Bobic, 1998). The elongated body shape, reduced and simplified ap- pendages and absence of eyes clearly indicate their connection with such habitats. From more than 50 known species of the genus Parastenocaris in Europe, less than one tenth of them are found in the Alps (Kiefer, 1978; Janetzky et al., 1996). In Slovenia, which is in the southern part of Cent- ral Europe, species of the genus Parastenocaris have not previously been found. In nearby countries (Italy; Austria, Dinaric region and Macedonia), the genus is quite common, with several new species described from there (Kiefer, 1933, 1938, 1968; Chappuis, 1935; Petkovski, 1959). Subterranean habitats in Slovenia, except those in caves and dug wells, have been re- latively poorly investigated. Only a few systematic surveys, which included also microcrustacean fauna, were done in ground water near Ljubljana and thermal springs in NE Slovenia (Sket, 1981a, b). An intensive sampling of water from dug wells (depth from 2 m to >25 m) in alluvial plains all over Slovenia resulted in Cyclopoida (genera Diacyclops and Acanthocyclops) but no Harpacticoida (Brancelj, unpubl.). During the last year, several samplings of inter- stitial fauna from bore wells were made during a survey of aquifers for water supply. Bore wells were drilled to different depths (from 5 m to over 50 m) in alluvial gravel plains and along rivers. In several samples we obtained some specimens of Cyclopoida as well as Harpacticoida. Harpacticoida were repres- ented mainly by genera Bryocamptus and Attheyella, including species common to both epigean and sub- terranean habitats (Brancelj, unpubl.). In this paper, a new species from genus Parastenocaris is described in detail. Materials and methods Water from a bore well (capacity of about 5.5 l s -1 )