Pseudachorutes dubius Krausbauer, 1898

Kaprus’, Ighor J. & Weiner, Wanda M., 2009, The genus Pseudachorutes Tullberg, 1871 (Collembola, Neanuridae) in the Ukraine with descriptions of new species, Zootaxa 2166, pp. 1-23 : 17-18

Pseudachorutes dubius Krausbauer, 1898

Redescription. Body length without antennae 1.50–2.85 mm. Colour dark bluish-grey (on slide), ocular plate bluish-black. Tegumental granulation coarse, dense and uniform.

Antennae are long as the head approximately. Ant. I with 7 setae, Ant. II with 11 setae and Ant. III with 19 ordinary setae. Ant. III and IV fused dorsally, ventral separation well marked. Sensory organ of Ant. III consisting of: two small, oval sensilla, two subcylindrical guard sensilla (ventral sensillum as long as dorsal one) and two guard setae between them; ventral microsensillum present. Ant. IV with about forty five ordinary setae, 9–10 modified setae in ventro-apical part and 6 thin subcylindrical sensilla; dorsoexternal microsensillum and subapical organite present; apical vesicle divided on three lobes.

PAO oval with 14–20 vesicles, 1.35–1.60 times larger than ocellus B. Eyes 8+8. Buccal cone short. Mandible fork-like, with two small teeth near apex. Styliform maxilla with two lamellae, one of them with tiny apical hook. Labral formula: 4/2,3,4. Labium with 12+12 ordinary setae, no apical organite x, but an internal stylet visible near apex. Perilabial area with 4+4 subequal setae.

Dorsal chaetotaxy with short setae and with longer sensory setae s. Formula per half tergum as: 022/ 11111. Microsensilla on Th. II present. Head with unpaired seta d1 and without a0 seta. Th. I with 4+4 setae. Th. II and III with 10+10 setae (a2, a5 and m4 setae absent). Abd. I–III with 8+8 setae (a6, a3 setae absent and m4 setae present), Abd. IV with 11+11 setae (m4, m6 setae present), seta s = seta p5. Abd. V without a2 and with p2 setae, seta s = p3.

Ventral chaetotaxy: thoracic sterna without setae, VT with 3+3 setae, Abds. I without setae, Abds. II with 3+3 setae, Abds. III with 6–7+6–7 setae.

Dens with six setae. Mucro boat-shaped, with curved ventral edge and broad lateral lamella. Manubrium with 12–13+12-13 setae. Tenaculum with 3+3 teeth. Each anal valve with two setae hr.

Tibiotarsi I, II and III with 18, 18 and 17 setae, respectively, setae M and B7 absent on tibiotarsus III. Femora I, II and III with 12, 12 and 11 setae, trochanters I, II and III with 6, 6 and 6 setae, coxae I, II and III with 3, 6 and 7 setae, subcoxae 2 of legs I, II and III with 0, 2 and 2 setae, subcoxae 1 of legs I, II and III with 1, 2 and 2 setae, respectively. Claw with a strong tooth near middle of inner edge and a pair of strong lateral teeth in basal part. Empodial appendage absent.

Material examined. 2 females and 7 juveniles (on slides), Ukraine, Ivano-Frankivs’k district, Karpats’ky National Park, near Vorochta village, Chornohora ridge, Pozhyzhevska Mt., 1750 m alt., Duschekia viridis and Pinus mugo crooked forest, moss, 20.VIII.1993, leg. I. Kaprus’; 1 female (on slide), Ukraine, Ivano- Frankivs’k district, near Mykulychyn village, Gorgany ridge, 700 m alt., Fagus and Abies forest, moss, 25.VI.1991, leg. I. Kaprus’; 1 female (on slide), Ukraine, L’viv district, near Skole town, Skolivs’ki Beskydy ridge, 500 m alt., Fagus forest, leaf litter and soil, 7.IX.2004, leg. V. Javornytsky; 1 male and 3 females (on slides), Ukraine, Chernivtsi district, near Perkalab village, Chyvchyny ridge, Chyvchyn Mt., 1000 m alt., Alnus forest, leaf litter, 2.VIII.1992, leg. I. Kaprus’; 2 females (on slides), Ukraine, Zakarpattya district, near Julivtsi village, Julivs’ky Hills, Quercus and Carpinus forest, leaf litter, 6.IV.1989, leg. I. Kaprus’; 2 males and 2 females (on slides), Ukraine, L’viv district, near Mykolaiv town, Quercus forest, leaf litter and soil, 7.X.1999, leg. I. Kaprus’; male and 2 females (on slides), Ukraine, L’viv district, near Javoriv town, Roztochchya Hills, Pinus forest, leaf litter and soil, 7.VIII.2003, leg. V. Javornytsky; 1 female (on slide), Ukraine, Volyn’ district, near Shats’k town, Pinus forest, leaf litter, 7.XII.1977, leg. V. Melamud; 1 female (on slide), Ukraine, Zhytomyr town, Pinus-Quercus forest, leaf litter and soil, 5.II.2008, leg. I. Kaprus’; male (on slide), Ukraine, Ternopil’ district, Grymajliv village, Medobory Reservation, Carpinus forest, soil, 20.VI.1994, leg. I. Kaprus’; 1 female (on slide), Ukraine, Donetsk district, near Bohorodychne village, Quercus forest, 2.VIII.1997, leg. I. Bondarenko.

Biology. Pseudachorutes dubius has been collected in the forest habitats of Ukraine, besides the Crimean Peninsula. Bisexual forest species.

Remarks. A recent morphological description of P. dubius was published by Fjellberg (1998) using material from Fennoscandia and Denmark. Morphological characters of the Ukrainian specimens fit this description. Pseudachorutes dubius is related to Pseudachorutes vitalii sp.nov. Differences between the two species are given in Table 1.