Pseudachorutes subcrassus Tullberg 1871

Pseudachorutes subcrassus Tullberg, 1871

Figs 53, 59, 60, 78

Redescription. Body length without antennae 0.95–1.90 mm. Colour in alcohol bluish-grey, ocular plate bluish-black. Tegumental granulation coarse, dense and uniform.

Antennae shorter than head. Ant. I with 7 setae, Ant. II with 12 setae and Ant. III with 18–20 ordinary setae. Ant. III and IV fused dorsally, ventral separation well marked. Sensory organ of Ant. III consisting of: two small, slightly bent internal sensilla, two subcylindrical guard sensilla (ventral sensillum longer 1.30 times than dorsal one) and two guard setae between them; ventral microsensillum present. Ant. IV with about forty ordinary setae, 15–18 modified setae in ventro-apical part and six distinct subcylindrical sensilla; dorsoexternal microsensillum and subapical organite present; apical vesicle always trilobed (Figs 54 c, 60).

PAO with 9–12 vesicles, as long as 0.9–1.0 times ocellus B. Eyes 8+8. Buccal cone elongated. Mandible with four teeth (two inner teeth are equal approximately) (Fig. 59), styliform maxilla with two lamellae; one of them hooked. Labral formula: 4/2,3,3,4 (Fig. 78). Labium with 2+2 organites x and papillate seta L, with 12+12 ordinary setae. Perilabial area with 5+5 subequal setae.

Dorsal chaetotaxy with mesosetae and longer sensory setae s. Formula per half tergum as: 022/11111. Body setae slightly thickened and serrated towards tip of abdomen. Microsensilla on Th. II present. Head with unpaired seta d1 and without a0 seta. Chaetae sd3 on the head level with or somewhat anterior to d2 chaetae (Fig. 53). Th. I with 3+3 setae. Th. II with 11+11 setae (setae a2 present and a5, m4 absent) and Th. III with 10+10 setae (setae a2, a5 and m4 absent). Abd. I–III with 8+8 setae (m-row and a3 setae absent), Abd. IV with 9+9 setae (m-row setae absent), seta s = p5. Abd. V with a2 and without p2 setae, seta s = p3.

Ventral chaetotaxy: thoracic sterna without setae, VT with 4+4 setae, Abds. I without setae, Abds. II with 4+4 setae, Abds. III with 6–7+6–7 setae.

Dens with six setae. Mucro slightly hooked with 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 19, 19 and 18 setae, respectively, seta B7 absent on tibiotarsus III. Femora I, II and III with 12–13, 11–12 and 11 setae, trochanters I, II and III with 6, 6 and 6 setae, coxae I, II and III with 3, 7 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 small inner tooth and without lateral teeth. Empodial appendage absent.

Material examined. 4 females, 2 males (on slides), Ukraine, Ivano-Frankivs’k district, Karpats’ky National Park, near Vorochta village, Chornohora ridge, Pozhyzhevska Mt., 1600–1800 m alt., Picea forest and Pinus mugo crooked forest, leaf litter, 27.VI.1991, leg. I. Kaprus’; 2 females, male and juveniles (on slides), Ukraine, Ivano-Frankivs’k district, near Mykulychyn village, Gorgany ridge, 700 m alt., Pinus relict forest, leaf litter and moss, 26.III.1991, leg. I. Kaprus’; 3 males and 15 females (on slides), Ukraine, L’viv district, near Skole town, Skolivs’ki Beskydy ridge, 1000 m alt., Fagus and Abies forest, leaf litter and soil, 8.XI.1989, leg. I. Kaprus’; 2 males and 4 females (on slides), Ukraine, Chernivtsi district, near Perkalab village, Chyvchyny ridge, Chyvchyn Mt., 1200 m alt., Picea abies forest, leaf litter and moss, 14.VIII.1990, leg. I. Kaprus’; 3 males and 4 females (on slides), Ukraine, L’viv district, near Mykolaiv town, Populus forest, leaf litter and soil, 27.X.1999, leg. I. Kaprus’; 3 males and 7 females (on slides), Ukraine, L’viv district, near Ivano-Frankove village, Roztochchya Hills, Fagus forest, leaf litter and moss, 28.VIII.1988, leg. I. Kaprus’; 1 female (on slide), Ukraine, Volyn’ district, near Bils’ka Volya village, Bile Lake, Pinus forest, leaf litter and soil, 25.VII.2004, leg. I. Kaprus’.

Biology. Pseudachorutes subcrassus has has been collected in the forest litter and mosses. Bisexual forest species.

Remarks. Pseudachorutes subcrassus belongs to the species group of Pseudachorutes with 2+2 organites x and papillate seta L on labium, with 12 setae on labrum (labral formula: 4/2,3,3,4), with unpaired seta d1 on the head and with 11+11 setae on Th. II (a2 setae present, a5 setae absent). Morphological characters of the Ukrainian specimens of P. subcrassus fit the recent descriptions of this species from Spain and Fennoscandia which were published by Jordana et al. (1997) and Fjellberg (1998). This species similar to Pseudachorutes parvulus Börner, 1901, but is readily identified by presence of modified setae in ventro-apical part of Ant. IV, the shape of mandible and four prelabral setae (see descriptions of P. parvulus and P. subcrassus).