Abstract

Two new aquatic oligochaete species are described from tufa barriers in Croatia. The reproductive system in the phallodriline Aberrantidrius mihaljevici Vučković et al. n. sp. conforms to the general pattern in the genus but it is distinguished by a combination of characters, including the shape and length of penial chaetae (3 times the mean length of somatic chaetae), atrium shape and spermathecal pore position (anterior in the postatrial segment). The lumbriculid Stylodrilus tofaceus Rodriguez et al. n. sp. is mainly distinguished from congeners by the spindle-shaped spermathecal ducts with high lining epithelium, and position of the spermathecal pores. These two new taxa reveal that aquatic oligochaete communities in tufa barriers of karstic regions may be of particular interest with respect to diversity of endemic taxa, and also for study of colonization routes of this interesting habitat, with possible relations with groundwaters. The finding of one specimen attributable to the genus Eclipidrilus may open ainteresting research on the biogeography of this Nearctic genus.