Pseudachorutes scythicus, Kaprus’, Ighor J. & Weiner, Wanda M., 2009

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 : 3-5

Pseudachorutes scythicus sp. nov.

Figs 1–10 , 80

Description. Body length without antennae 1.15–1.40 mm. Colour in alcohol bluish-grey, ocular plate bluishblack. Tegumental granulation strong.

Antennae shorter than head. Ant. I with 7 setae, Ant. II with 12 setae and Ant. III with 20 ordinary setae. Ant. III and IV fused dorsally, ventral separation well marked. Sensory organ of Ant. III consisting of two small, globular internal sensilla, two subcylindrical guard sensilla (ventral sensillum longer 1.15 times than dorsal one) and two guard setae between them; ventral microsensillum present. Ant. IV with about fifty ordinary setae and 6 distinct subcylindrical sensilla; dorsoexternal microsensillum and subapical organite present; apical vesicle trilobed ( Figs 2–3 ).

PAO round with 10–12 vesicles, 1.5–2.0 times larger than ocellus B ( Fig. 5 ). 8+8 eyes. Buccal cone short. Mandible with three teeth, inner tooth situated subapically. Styliform maxilla with three lamellae, one of them with tiny apical hook ( Fig. 7 ). Labral formula: 4/2,3,3,4 ( Fig. 80 ). Labium without organites x and papillate setae L, with 12+12 ordinary setae ( Fig. 4 ). Perilabial area with 5+5 subequal setae.

Dorsal chaetotaxy as in Fig. 1 with mesochaetae and with longer sensory setae s. Formula per half tergum as: 022/11111. Microsensilla on Th. II present. Head with unpaired seta d1 and with setae a0. Th. I with 4+4 setae.

Th. II with 13+13 setae (a2, a5 and m4 setae present) and Th. III with 12+12 setae (a2 setae absent and a5, m4 setae present). Abd. I–III with 10+10 setae (m3 and m4 setae present, a3 setae absent) and Abd. IV with 9+9 setae (m-row setae absent), seta s = p5. Abd. V with a2 setae present and p2 setae absent, s = p3.

Thoracic sterna without setae. Chaetotaxy of abdominal sterna as in Fig. 10 . VT with 4+4 setae, Abds. I without setae, Abds. II with 5+5 setae, Abds. III with 9–10+9–10 setae.

Dens with six setae ( Fig. 9 ). Mucro slightly hooked with broad and long lateral lamella. Manubrium with 15+15 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 ( Fig. 8 ). 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, 7 and 8 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 strong inner tooth and without lateral teeth ( Fig. 8 ). Empodial appendage absent.

Type material. Holotype: male (on slide), Ukraine, Kherson district, Chornomors’ky Biosphere Reserve, “Jahorlyc’ky kut” part, steppe plant community, soil, 2.V.2006, leg. I. Kaprus’. Paratypes: 3 males and 1 female (on slides), the same data as holotype. The material is preserved in the following collections: holotype, 3 paratypes (2 males and 1 female) in SNHMU, one paratype (male) in ISEA.

Other material. 1 male and 2 females (on slides), Ukraine, Donets’k district, Kamiani Mohyly Reserve, steppe plant community, soil, 28.IV.1998 and 23.X.1993, leg. O. Starostenko; 1 juvenile, Ukraine, Mykolaiv district, Jelanetsky Step Reserve, steppe plant community, soil, 26.V.1998, leg. V. Rizun; 1 juvenile, Ukraine, Dnipropetrovs’k district, near Novomoskovs’k town, steppe with Stippa sp., soil, 18.VI.1985, leg. O. Makarova.

Etymology. The species name is derived from the name of the ancient Scythia state which existed on the territory of South Ukraine.

Biology. The species has been collected only in xerophytic habitats. It is probably connected with steppe communities of southeastern Europe. Bisexual.

Discussion. The new species is related to Pseudachorutes sibiricus Rusek, 1991 and Pseudachorutes plurichaetosus Arbea & Jordana, 1991 . These three species have the same number of setae on Th. I (4+4 setae) and on dens (6 setae), the same type of apical bulb (trilobed), mucro (with long and broad lateral lamella) and claw (with strong inner teeth and without lateral ones). The chaetotaxy of P. scythicus sp. nov. and P. sibiricus is similar, but variable in P. sibiricus (A. Babenko pers. comm.). These two species differ in the number of postantennal vesicles (10–12 in P. scythicus and 19 in P. sibiricus ), in the shape of mandible (with subapical tooth in the new species and without this tooth in P. s i b i r i c u s). In P. s c y t h i c u s Ant. IV has short and thick sensilla (6), whereas P. sibiricus has long, slim ones (also 6). In the other hand they occupy different habitats. Pseudachorutes sibiricus is known from moist habitats in taiga forest with mosses,. On the contrary, P. s c y t h i c u s lives in soil of the dry steppe plant communities. Pseudachorutes plurichaetosus differs from these two species by the absence of a0 setae on head, a5 and m4 setae on Th. II and III, m4 setae on Abd. I-III and by the chaetotaxy of plurochaetotic type on Abd. IV and V. It has labium with 1+1 small organites x between A, B, C and D setae. This morphological structure is absent in P. sibiricus and P. scythicus .

Figures

FIGURES 1 – 10. Pseudachorutes scythicus sp. nov. 1, dorsal chaetotaxy of body; 2, Ant. III and IV dorsally; 3, Ant. III and IV ventrally; 4, labial chaetotaxy; 5, PAO and eyes; 6, mandible; 7, maxilla; 8, distal part of leg III; 9, furca; 10, chaetotaxy of Abds. I – 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.