Six genera of Ariophantidae from Bhutan (Gastropoda, Eupulmonata, Helicarionoidea)

Samples of the ariophantid genera Oxytesta, Bensonies, Himalodiscus, Ariophanta, Khasiella, and Sesara collected in Bhutan are treated. For all species distributional data for the kingdom are summarized on maps. Shells are described and figured on the basis of specimens from Bhutan, with radulae and genital tracts whenever possible. Six Oxytesta species are dealt with, 3 of which new to science, viz. O. delicata E. Gittenberger & Sherub, O. dubitata E. Gittenberger & Kezang Tobgay, and O. lhuentsensis E. Gittenberger & Sherub. Five Bensonies species are recognized, one of which could not be identified and 4 are described as new, viz. B. bhudepressa E. Gittenberger & Kezang Tobgay, B. bhutanensis E. Gittenberger, Kezang Tobgay & Choki Gyeltshen, B. minorcamura E. Gittenberger & Sherub, and B. tshelingor E. Gittenberger & Sherub. Himalodiscus cf. echinatus is reported from outside Nepal. New records for Ariophanta himalana determine its northernmost distributional boundary in Bhutan. Five Khasiella species are described, 3 of which as new, viz. K. falcatoides E. Gittenberger & Kezang Tobgay, K. biconica E. Gittenberger, Choki Gyeltshen & Kezang Tobgay, and K. lenticularis E. Gittenberger, Choki Gyeltshen & Nima Gyeltshen. The widespread Sesara diplodon is reported for also Bhutan