Xenylla weinerae, Jia & Skarżyński, 2019

Jia, Junli & Skarżyński, Dariusz, 2019, A new species of Xenylla Tullberg, 1869 (Collembola: Hypogastruridae) from China, with a key to Asian species of the genus, Zootaxa 4608 (3), pp. 579-585 : 580

Xenylla weinerae sp. nov.

Figs 1–8

Description. Body length 0.8–1.2 mm (n = 8). Colour (in ethanol): dorsal side blue gray to black, with pale spots all over the body, ventral side paler. Granulation fine and uniform, 8–10 granules between setae p 1 on Abd. V.

Ant. IV with simple (or slightly subdivided) apical vesicle (av), subapical organite (or), microsensillum (ms), 6 (3 dorsoexternal: A–C and 3 dorsointernal: D–F) cylindrical, thickened sensilla ( Fig 1 ) and 7–10 short pointed setae in ventral file. Ant. III-organ with subequal and rather small dorsal and ventral guard sensilla, two short bent inner sensilla ( Fig 1 ), ventral microsensillum present. Ant. I with 7 setae.

Ocelli 5 + 5 ( Fig. 2 ). Labrum with apical papillae. Labral setae 5, 5, 4, prelabrals 4. Labium with 4 setae in basomedian field and 5 in basolateral, seta F about two times longer than seta E ( Fig. 7 ). Labial palp with 6 proximal setae, 5 papillae (A-E), 10 guard setae (short and blunt at the tip: a 1, b 1, b 2, d 2; prolonged: b 3, b 4, d 3, d 4, e 3 and e 4) and 3 hypostomal setae (H, h1-2) (see Fig. 12 in Skarżyński et al. 2018). Head of maxilla with six lamellae, of which 1 and 2, with marginal filaments, protrude clearly above the teeth (see Fig. 11 in Skarżyński et al. 2018). Outer lobe of maxilla with 2 sublobal hairs.

Dorsal chaetotaxy ( Figs 2–4 ). Setae short and slightly serrated. Body sensilla (s) 2– 3 x longer than ordinary setae, fine and smooth. Head with setae a 0, c 2, c 3; c 1 absent (b), setae l 1 subequal to l 3. Th. I with 3 + 3 setae in a row. Th. II and III with setae a 2 displaced posteriorly compared with setae a 1 (h1), setae p 2 displaced anteriorly compared with setae p 1 (h2); setae p 3, m 3 and la 1-3 present. Abd. I–III with setae p 5. Abd. IV with setae m 3, m 5; a 3 and p 3 present or absent. Setae a 2 on Abd. V absent (q).

Ventral chaetotaxy ( Figs 7, 8 ). Head with setae p 1 and m 3. Th. II and III without medial setae (t). Abd. II with setae a 6, p 1, p 6 present and a 5, p 2 absent, Abd. III with setae p 5 present and medial/median setae (in front of retinaculum) absent, Abd. IV with seta m 1. Two anterior anal valves with 2 setae hr each.

Tibiotarsi I, II and III with 19, 19 and 18 setae respectively, with setae A 2 and A 7 capitate ( Fig. 6 ), ratio capitate setae/inner edge of claw III = 1.2–1.3. Chaetotaxy of legs I, II and III respectively as: femora with 10–12, 10–11 and 9–10; trochantera with 4–5, 4–5 and 4; coxae with 3, 7–8 and 6–7; subcoxae 2 with 0, 2 and 2; subcoxae 1 with 1, 2 and 3. Claws with inner tooth on upper third near apex ( Fig. 6 ).

Ventral tube with 4 + 4 setae ( Fig. 8 ). Retinaculum with 3 + 3 teeth. Furca complete and well developed, ratio dens + mucro/inner edge of claws III = 2.4–2.5. Mucro separated from dens with boat shaped apex and inner lamella. Ratio dens/mucro = 1.5–1.7. Dens with two posterior setae ( Fig. 5 ). Anal spines small, situated on low basal papillae ( Fig. 4 ).

Type material. Holotype: female. Surface of small puddles in a stream valley, Lu Yuan Gou Village (N 35° 45´, E 111° 02´), Lüliang Mountains, Shanxi Province, China, 7.vii. 2016, leg. Junli Jia. Paratypes: 7 females, same data as holotype . Holotype and 4 paratypes are deposited at the Institute of Environmental Biology, Wrocław Univer- sity, Poland and 3 paratypes—in the collection of the College of Life Science , Shanxi Normal University , Linfen , China .

Etymology. Dedicated to Wanda M. Weiner, the excellent specialist in Collembola .

Remarks. The vast majority of Xenylla species have four thickened cylindrical sensilla on Ant. IV. X. weinerae sp. nov. belongs to a small group of species (together with X. acauda Gisin, 1947 (Europe, Japan, USA, Mexico), X. brevicauda Tullberg, 1869 (Europe) , X. caudata Jordana, 1993 ( Spain) , X. lesnei Denis, 1935 ( Mozambique) , X. nirae Gama & Oliveira, 1994 ( Brasil) , X. wandae Queiroz & Mendonça, 2016 ( Brasil) and X. vanharteni Weiner et al., 2012 ( Yemen) having six such sensilla ( Tullberg 1869; Denis 1935; Gisin 1947; Jordana, 1993; Babenko et al. 1994; Gama & Oliveira 1994; Thibaud et al. 2004; Weiner et al. 2012; Queiroz & Mendonça 2016). X. acauda , X. brevicauda and X. caudata can be easily distinguished from X. weinerae sp. nov. by the absence of furca and retinaculum (the first mentioned) or by the mucro fused with the dens and 2 + 2 teeth in retinaculum (the two last mentioned). Easy to separate are also these species, which share with a new species well developed furca (mucro separated from the dens with two setae). X. nirae and X. lesnei have long and thin dorsointernal sensilla E and F on Ant. IV and tibiotarsi I with one capitate tenent hair (vs short and thick dorsointernal sensilla E and F on Ant. IV, tibiotarsi I with two capitate tenent hairs), X. wandae possess the peculiar creased cuticular structures on Abd. IV, outer lobe of maxilla with 3 sublobal hairs, head with setae c 1 and c 2 and sterna of Th. II and III with 1 + 1 setae (vs creased cuticular structures on Abd. IV absent, outer lobe of maxilla with 2 sublobal hairs, head with setae c 1 absent and c 2 present and without ventral setae on Th. II and III), while X. vanharteni has mucro with hook at the top (vs hook at the top absent) and different chaetotaxy (head with dorsal setae l 3 longer than l 1 and without ventral setae p 1, Th. II and III without dorsal setae m 3 and p 3, Abd. IV without dorsal setae m 3, vs head with dorsal setae l 1 and l 3 subequal, ventral setae p 1 present, Th. II and III with dorsal setae m 3 and p 3, Abd. IV with dorsal setae m 3). X. wein- erae sp. nov. has unique, moderately modified chaetotaxy (b h1 h2 q t). Such a set of features is characteristic also for some populations (Nepal– – Gama (1988), Central Yakutia– – Babenko et al. (1994)) of X. obscura Imms, 1912 sensu Thibaud et al. (2004 . These populations share with a new species subequal dorsal setae l 1 and l 3 on the head, dorsal setae a 3 on Abd. IV and mucro with boat shaped apex and inner lamella. Moreover, population from Yakutia is similar to a new species due to outer lobe of maxilla with 2 sublobal hairs (state of this feature in the populations from Nepal is unknown). X. obscura differs clearly from X. weinerae sp. nov. in having only four (populations from Nepal) or five (population from Yakutia) cylindrical thickened sensilla on Ant. IV. Differences between X. weinerae sp. nov. and other species of the genus Xenylla recorded from Asia illustrates the identification key below.

Figures

FIGURES 1–6. X. weinerae sp. nov.: 1, dorsal chaetotaxy of Ant. III–IV; 2, dorsal chaetotaxy of head; 3, dorsal chaetotaxy of Th. II and III; 4, dorsal chaetotaxy of Abd. III–VI; 5, dens and mucro; 6, tibiotarsus and claw III.

FIGURES 7–8. X. weinerae sp. nov.: 7, ventral chaetotaxy of head; 8, ventral chaetotaxy of Abd. I-IV. Abbreviations in text.