Systematic revision of the Plectopylinae (Gastropoda, Pulmonata, Plectopylidae) Author Páll-Gergely, Barna 31E196E9-5A51-4295-9A36-D5DA689502B7 Centre for Agricultural Research, Hungarian Academy of Sciences (MTA), Herman Ottó Street 15, Budapest, H- 1022, Hungary. pall-gergely.barna@agrar.mta.hu text European Journal of Taxonomy 2018 2018-08-16 455 1 114 journal article 22297 10.5852/ejt.2018.455 44a2fcf6-cc1b-4c07-9554-dd6dd279a76d 3817707 C445E95B-446A-4601-AAA3-C1CCBAB627F9 Chersaecia perarcta simplex ( Solem, 1966 ) comb. nov. Figs 21L–M, 22E–H Plectopylis ( Chersaecia ) simplex Solem, 1966: 97–101 , figs 23c–g, 24, pl. 3, figs a–c [“Chieng Dao, North Thailand at 1,200 –1,300 meters elevation”]. Chersaecia simplex – Páll-Gergely et al. 2015c: 10 . Diagnosis Main plica absent. Material examined Paratypes THAILAND : 2 broken specimens (preserved in ethanol: PL122 used for molecular study, the other, nearly intact shell: D = 12.6 mm ), S.E. Asien, N. Thailand, Chieng Dao, O.H., 1200–1700 m a.s.l., 1 Jul. 1960 , Degerbøl leg. (nr. 979) (ZMUC-GAS-487). Description MEASUREMENTS (in mm). D = 12.6, H = 4.1 (n = 1, ZMUC-GAS-487). CHARACTERS OF THE GENITAL SYSTEM. I examined the ethanol-preserved Chersaecia perarcta simplex genitalia, which were dissected out by Solem. I found an opened penis of one specimen ( Fig. 22H ), and the complete genitalia separated into two parts of another one ( Fig. 22G ). One part of the second specimen included the penis, its retractor muscle, the vagina, the distal part of the spermoviduct, and the stalk of the bursa copulatrix (the bursa itself was missing), whereas the other part contained the proximal genitalia (remaining part of spermoviduct, albumen gland, etc.). I can confirm that the diverticulum is absent, just as Solem (1966) reported. There were also some eggs in the vial, probably from the same specimen which had the complete genitalia preserved. The structure described by Solem (1966) as a “small vergic papilla” is a thickening of the folds of the penial wall, and not homologous with the penial papilla of Helicoidea, etc., which is an extended part of the epiphallus to the penis lumen. Differential diagnosis The shell shapes of Chersaecia perarcta and Plectopylis simplex do not differ. The nominotypical subspecies possesses the main plica, which is lacking in C. perarcta simplex . Distribution Chersaecia perarcta simplex is known from the type locality only ( Fig. 9 ). Remarks Because of the indistinguishable outer-shell characters, Plectopylis ( Chersaecia ) simplex is assigned as a subspecies of C. perarcta . The difference between the two forms is only the presence/absence of the parietal plicae.