Pseudachorutes corticicolus ( Schäffer, 1896 ), Schaffer, 1896

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 : 16-17

Pseudachorutes corticicolus ( Schäffer, 1896)

Figs 55, 57, 58, 63, 64 , 76

Redescription. Body length without antennae 0.65–1.30 mm. Colour in alcohol bluish-grey, ocular plate bluish-black. Tegumental granulation fine, uniform.

Antennae shorter than head. Ant. I with 7 setae, Ant. II with 12 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, slightly bent internal sensilla, two subcylindrical guard sensilla (ventral sensillum longer 1.2–1.3 times than dorsal one) and two guard setae between them; ventral microsensillum present. Ant. IV with about fifty ordinary setae, 8-9 modified setae in ventro-apical part and six distinct subcylindrical sensilla; dorsoexternal microsensillum and subapical organite present; apical vesicle trilobed.

PAO round with 6–9 vesicles, 1.6–1.9 times larger than ocellus B. Eyes 8+8. Buccal cone elongated. Mandible with four teeth (tooth in the angle of mandible large, subapical tooth smaller than medial one) ( Fig. 57 ). Styliform maxilla with two hooked lamellae ( Fig. 58 ). Labral formula: 4/2,3,4 ( Fig. 76 ). Labium without organites x and papillate setae L, with 12+12 ordinary setae ( Fig. 55 ). Perilabial area with 5+5 subequal setae.

Dorsal chaetotaxy with short, acuminate or blunt setae on Abd. IV–VI and longer sensory setae s ( Fig. 64 ). Formula per half tergum as: 022/11111. Microsensilla on Th. II present. Head with unpaired seta d1 and without a0 seta. Th. I with 3+3 setae. Th. II with 12+12 setae (a2 and a5 setae present, m4 setae absent) and Th. III with 11+11 setae (a2 and m4 setae absent, a5 setae present). Abd. I–III with 9+9 setae (m4 setae present 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 5–6+5–6 setae, Abds. III with 6–7+6–8 setae.

Dens with six setae. Mucro hooked with broad lateral lamella. Manubrium with 15+15 setae. Tenaculum with 3+3 teeth. Each anal valve with two setae hr.

Tibiotarsi with one clavate tenent hair (A1 seta) ( Fig. 63 ). Tibiotarsi I, II and III with 19, 19 and 18 setae, respectively, seta B7 absent on tibiotarsus III. Femora I, II and III with 13, 12 and 11 setae, trochanters I, II and III with 6, 6 and 6 setae, coxae I, II and III with 3, 8 and 8 setae, subcoxae 2 of legs I, II and III with 0, 3 and 3 setae, subcoxae 1 of legs I, II and III with 1, 2 and 2 setae, respectively. Claw with inner tooth and without lateral teeth ( Fig. 63 ). Empodial appendage absent.

Material examined. 1 female (on slide), Ukraine, Ivano-Frankivs’k district, Gorgany ridge, near Bystrycia village, Fagetum forest, leaf litter, 13.I.1998, leg. R. Godun’ko; male (on slide), Ukraine, L’viv district, near Skole town, Skolivs’ki Beskydy ridge, 700 m alt., Fagus forest, moss on a tree, 18.V.1990, leg. I. Kaprus’; 1 female (on slide), Ukraine, near Odesa town, xerothermic meadow, soil, 15.V.2008, leg. A. Susulovsky; 2 females (on slide), Ukraine, Zakarpattya district, near Uzhhorod town, Quercus and Carpinus forest, leaf litter, 15.X.2007, leg. K. Goblyk; male and 2 females (on slides), Ukraine, L’viv district, near Ivano-Frankove village, Roztochchya Reservation, Fagetum forest, under the bark, 6.V.1993, leg. I. Kaprus’; 2 females (on slide), Ukraine, L’viv district, near Zolochiv town, Hologory Hills, Pinus forest, moss, 7.XII.1991, leg. I. Kaprus’.

Biology. Pseudachorutes corticicolus lives in the forest habitats and xerothermic meadows. Bisexual corticolous species.

Remarks. Pseudachorutes corticicolus belongs to the species group of Pseudachorutes without organites x and papillate seta L on labium, with one clavate tenent hair on tibiotarsi, with unpaired seta d1 on the head, and with 12+12 setae on Th. II (a2 and a5 setae present). Morphological characters of the Ukrainian specimens of this species fit the recent description of this species from Fennoscandia and Denmark which was published by Fjellberg (1998). Pseudachorutes corticicolus is closest to Pseudachorutes columbicus Rusek, 1991 from Canada and Pseudachorutes janstachi sp. nov. It differ from P. c o l u m b i c u s in the absence a0 seta on head and the presence 3+3 setae on Th. I (a0 present, 4+4 setae in P. c o l u m b i c u s), in the presence 9 setae on labrum (10 setae in P. columbicus ) and shape of mandible (with four teeth in P. corticicolus and three teeth in P. columbicus ). Differences between P. corticicolus and P. janstachi are given above.

Specimens of P. corticicolus described by Jordana et al. (1997) from Spain belong to another species, maybe new to science. It differ from Ukrainian and Scandinavian material by the absence of a5 setae on Th. V, m4 setae on Abd. I–III and a2 setae on Abd. V and by the presence of lateral teeth on the claw.

Figures

FIGURES 52 – 64. Pseudachorutes parvulus Börner, 1901. 52, dorsal chaetotaxy of body; 54 a, apical vesicle simple; 54 b, apical vesicle slightly trilobed; 54 c, apical vesicle strongly trilobed; 56, Ant. III and IV ventrally; 61 a, b, variants of mandibles; 62, maxilla; Pseudachorutes subcrassus Tullberg, 1871. 53, chaetotaxy of interocular area; 59, mandible; 60, Ant. III and IV ventrally; Pseudachorutes corticicolus (Schäffer, 1896). 55, right part of labium; 57, mandible; 58, maxilla; 63, distal part of leg III; 64, chaetotaxy of Abd. V and VI.

FIGURES 76 – 84. Shape and chaetotaxy of labrum: 76, Pseudachorutes corticicolus (Schäffer, 1896); 77, Pseudachorutes parvulus Börner, 1901; 78, Pseudachorutes subcrassus Tullberg, 1871; 79, Pseudachorutes pratensis Rusek, 1973; 80, Pseudachorutes scythicus sp. nov.; 81, Pseudachorutes janstachi sp. nov.; 82, Pseudachorutes palmiensis Börner, 1903; 83, Pseudachorutes vasylii sp. nov.; 84, Pseudachorutes vitalii sp. nov.