Xenylla gwiazdowiczi, Sternalski & Paśnik, 2019

Sternalski, Jakub & Paśnik, Grzegorz, 2019, A new species of Xenylla Tullberg, 1869 (Collembola: Hypogastruridae) from Peru, with a key to Neotropical species of the genus, Zootaxa 4711 (1), pp. 185-192 : 186

Xenylla gwiazdowiczi sp. nov.

Figs 1–15

Type material. Holotype female: Peru, basin of the Rio Yuyapichis , Panguana (9°36′49.32′′ S, 74°56′8.16′′ W), from rotting woods, 26.09,2011, leg. D. J. Gwiazdowicz. Paratypes: 8 females, 1 male, 1 juvenile and 11 specimens in alcohol: same data as holotype ( ISEA). Type material housed in ISEA .

Description. Body length range: 0.42 mm to 1.12 mm. Females: 0.77 mm to 1.12 mm; male: 0.7 mm to 0.95 mm; juvenile: 0.42 mm to 0.66 mm. Holotype length 0.95mm. Colour dorsally ranges from dark grey to greyish blue, ventral side paler with blue spots. Eye-patches well pigmented ( Fig. 1 ). Granulation uniform, 7–9 granules between setae p1 on Abd. V.

Antennae as long as head. Ant. I with 7 setae, Ant. II with 12 setae. Sensory organ of Ant. III consists of two curving, short rods in groove, guarded by blunt seta on each side ( Fig. 5 ). Ant IV with simple apical bulb, subapical organite, microsensillum (ms) and 4 thick, strongly bended sensilla– – 3 in dorsoexternal position and 1 placed in dorsointernal position ( Figs 5, 6 ). Ant. III and IV clearly separated ventrally.

Head with 5+5 ocelli ( Figs 1 , 3 ). PAO absent. Dorsally head with setae a0, d1–d5, sd3–sd5, c1–c5, p1–p5. Lateral setae l1 and l3 of equal size and slightly longer than other cephalic setae. Setae v1 present. Setae sd1 and sd2 absent ( Figs 3 , 10 ). Ventral head chaetotaxy with a1–a5, m1, m3–m5 and p1, p3–p5 setae, m2 and p2 absent ( Fig. 4 ). Mandibles with strong molar plate. Labral setae arranged according to the formula 2/4354 ( Fig. 7 , 11 ). Maxillary outer lobe with 2 sublobal hairs. Head of maxilla with six lamellae, other characters of maxilla not clearly visible. Labial palp of type A, 5 papillae (A–E), 6 guard setae.

Dorsal chaetotaxy ( Fig. 2 ): setae short and smooth. Setae on abdomen V–VI slightly serrated. Body s-chaetae smooth, 2 times longer than ordinary setae. Th. I with 3+3 setae. Th. II–III with setae a 2 in line with a1; without setae m2 and with setae p4 shifted backwards. Setae la1–la3 present. Abd. I–III with seta p5 present. Abd. IV with setae a3, m1 present and setae m3 and m5 absent. Abd. V with seta a2 absent. On abdomen IV–V setae a5 shifted forward.

Ventral side of thorax II–III without medial setae. Abd. II with seta a6 and p6 absent. Ventrally Abd. III without seta a6 and p5. Ventral tube with 4+4 setae ( Fig. 15 ). Furca fully developed ( Fig. 9 , 12 ); manubrium with 32 setae, rows a1–a3, m1–m3, p1–p3 present. Each dens with 2 setae posteriorly. Mucro clearly separated from dens, curved on apex with inner lamella present. Ratio dens/mucro = 0.60–0.69. Dens with two well marked incisions. Retinaculum with 3+3 teeth, without setae ( Fig. 15 ). Abd. VI with two very small, slightly curved anal spines on papillae ( Fig. 2 , 14 ). Anal valves with 14+14 setae.

Subcoxae of each leg with 2 setae. Trochanter of legs I–III with 4, 4–5, 4 setae respectively. Femora of legs I–III with 11, 11, 10 setae respectively ( Fig. 8 ). Tibiotarsi of legs I–III with 19, 19, 18 setae respectively. Two weakly clavate tenent hairs on each tibiotarsus I–III ( Figs 8 , 13 ). Claws with strong inner tooth near basis, empodium absent ( Figs 8 , 13 ).

Etymology. Dedicated to Professor Dariusz Gwiazdowicz, who collected the species described here during his expedition to Peru.

Discussion. Xenylla gwiazdowiczi sp. nov. is probably the most similar to X. spinosissima Najt & Rubio, 1978 and X. humicola ( Fabricius, 1780) . It shares with these species the following characters: head with 5 ocelli, mucro separated from dense, presence of seta c1–c2 on head, presence of 2 tenent hairs on each tibiotarsus, 4 thick sensilla on antennal segment IV and 2 setae on dens. X. humicola can be distinguished from the new species by the presence of very long dens, elongated and pointed mucro, body s-chaetae and setae equal in size and seta p2 on Th. II–III aligned with p1, whereas X. spinosissima differs by the presence of spiniform setae on abdomen and 17,17,16 setae on tibiotarsi respectively.

Figures

FIGURE 1. Xenylla gwiazdowiczi sp. nov.: Habitus in glycerol.

FIGURES 2–9. Xenylla gwiazdowiczi sp. nov.: 2—dorsal chaetotaxy; 3—dorsal head chaetotaxy; 4—ventral head chaetotaxy; 5—dorsal view of Ant. III–IV; 6—ventral view of Ant. III–IV; 7—labrum; 8—dorsal side of tibiotarsus I (ventral setae marked with dashed line); 9—furca.

FIGURES 10–15. Xenylla gwiazdowiczi sp. nov.: 10—dorsal chaetotaxy of head; 11—labrum; 12—furca; 13—tibiotarsus I; 14—anal spines on Abd. VI; 15—ventral tube and retinaculum.