Willowsia variabilis, Ma, Yitong, 2016

Ma, Yitong, 2016, Two new species of Willowsia (Collembola: Entomobryidae) from Guizhou Province, China, Zootaxa 4158 (1), pp. 137-145 : 141-144

Willowsia variabilis sp. nov.

Figs 5−8, 27−43

Types. Holotype: adult female on slide, China, Guizhou Province, Xingyi City, Dingxiao Town, Louna Village , 25°09′33″N, 105°02′35″E, altitude ca. 1300m, 20, April, 2014, Collection number: 1131, Collected by Shangze Wu with aspirator . Paratypes: 13 adult females on slides (5 specimens from collection number 1131; 8 from 1132), locality and collector same as holotype, 20−22, April, 2014. All deposited in Nantong University.

Description. Body length up to 2.0mm. Background colour pale yellow. Antenna, leg and manubrium with blue pigment. Eye patch dark blue. Blue pigment present on head and body, especially lateral side of head and body. ( Figs. 5−8).

Head. Antenna 0.52−0.60 times as long as body. Ratio of length of antennal segments I:II:III:IV = 1:1.1−1.5:1.1−1.3:2.0−2.4. Distal part of Ant. IV with sensory setae, normal ciliate setae and apical bulb bi-lobed ( Fig. 27). Dorsal cephalic chaetotaxy with 6−7 antennal (An), 5 median (M1−M4, an additional seta between M2 and M3) and 9 sutural (S0−S6, S 4i, S 5i). Interocular setae as pst. Eyes 8+8, G and H smaller ( Fig. 28). Labral setae as 4/5, 5, 4, all slender; prelabral setae ciliate, other smooth; labral papillae not clearly seen ( Fig. 29). Lateral process of labial palp straight, thicker than normal setae, with tip not reaching apex of labial papilla ( Fig. 30). Labial triangle setae as in Fig. 31, M4 rarely present, all finely ciliate.

Thorax. Dorsal macrochaetae shown as in Fig. 32. Th. II with 2 (m2, m 2i) medio-median, 2 (m4, m 4i) mediolateral and 23−25 posterior mac on each side. Th. III with 17−18 (p3 sometimes absent) median and 10 (m5, m 5i, a6, a 6i, a7, p5, p6, m6p, m6pe, m6) lateral mac on each side. Trochanteral organ with 49−52 smooth spiny setae ( Fig. 33). Unguis with 4 inner teeth, one pair located 0.44−0.50 distance from base of inner edge of unguis, distal unpaired two respectively at 0.63−0.71 and 0.87−0.90 distance from base. Unguiculus acuminate and outer edge serrate. Tenent hair thick with clavate tip, almost equal length to unguis ( Fig. 34).

Abdomen. Abd. IV 4.5−5.8 times as long as Abd. III along dorsal midline. Dorsal mac shown in Figs 35−37. Abd. I with 7−8 (m 2i, m2, m3, m4, a2, a3, a5, p5) mac, p5 sometimes absent. Abd. II with 5 (a2, m3, m3e, m3ea, m3ep) dorso-central, 1 (m5) lateral mac and 2 sensory chaetae. Abd. III with 2 (a2, m3) dorso-central, 3−4 (am6, pm6, p6, m7) lateral mac and 3 sensory chaetae, m7 sometimes absent ( Fig. 35). Abd. IV with 10−13 central and 18−19 lateral mac ( Fig. 36). Dorsal mac of Abd. V as in Fig. 37. Ventral tube anteriorly with 3 large and about 20 small ciliate setae besides some scales ( Fig. 38), and apically with 6−7 smooth and 18−20 ciliate setae of different sizes ( Fig. 39). Tenaculum with 4 teeth and 1 large striate seta ( Fig. 40). Manubrial plaque with 15−18 ciliate setae and 3−6 pseudopores on each side ( Fig. 41). Dens without spines, distal uncrenulated part of dens 1.4−1.5 times mucro in length. Mucro bidentate, two teeth subequal and tip of basal spine reaching subapical tooth ( Fig. 42).

Scales. Scales pale black, spinulate type, present on head, body, antennae, legs, ventral tube and manubrium ( Fig. 43).

Habitat. In rotten stem of rapeseed.

Etymology. Named after its variable colour pattern.

Remarks. The new species can be easily distinguished from other Willowsia species by its dorsal chaetotaxy. There are 27−28 mac on Th. III and 7−8 mac on Abd. I which is similar to that of W. potapovi Zhang, Chen & Deharveng, 2011 from the Caucasus and W. samarkandica Martynova, 1972 from Uzbekistan, but there are 2 dorso-central mac on Abd. III and 8 ciliate setae on labial triangle in the new species, whereas 3 on Abd. III and 5 on labial triangle in W. potapovi and W. samarkandica .

The two new species are somewhat similar in colour pattern of thorax and abdomen, but their differences are distinct. The antenna is pale yellow except distal part of Ant. IV with slight blue pigment and 4 macrochaetae present on Abd. I in W. pseudoshi sp. nov., while the whole of the antenna is pigmented blue and there are7−8 macrochaetae on Abd. I in Willowsia variabilis sp. nov.. The other differences are listed in Table 1.

Thirteen specimens were examined for chaetotaxy of W. variabilis and there is little variation on the body.