Willowsia bartkei Stach, 1965

Zhang, Feng, 2015, Some Willowsia from Nepal and Vietnam (Collembola: Entomobryidae) and description of one new species, Zootaxa 3905 (4), pp. 489-499 : 495

Willowsia bartkei Stach, 1965

Figs 26–32

Type locality. Vietnam: Cha-Pa.

Specimens examined. 7 females on slides and 14 in alcohol, all paratypes, Vietnam: Cha-Pa, alt. 1500 m, under stones and in moss, also under loose bark of trees and in litter in a forest, iii.1961, A. Bartke leg. All deposited in ISEA.

Redescription. Body length up to 2.3 mm.

Ground colour pale yellow in alcohol. Eye patches dark blue. Each antennal segment becoming gradually darker towards apex. Body dorsum with lateral stripes along mesothoracic margins, transverse bands on Abd. I posteriorly and Abd. II and III, and dark patches on posterior Abd. IV and V. Scattered pigment present on distal part of femora and tibiotarsi ( Fig. 26). Scales hyaline, leaf-like with tip pointed and finely striate; scales absent on antennae, legs and furcula ( Fig. 27 ).

Antenna 2.5 times as long as cephalic diagonal. Antennal segments ratio as I: II: III: IV = 1: 2: 2: 3. Ant. III organ with two rods. Antennal apical bulb unilobed. Labral margin with 4 conical papillae. Dorsal cephalic chaetotaxy with 6 sutural (S) mac; anterior area not clearly seen. Interocular area with 3 ciliate mic ( Fig. 28 ).

Dorsal mac shown in Fig. 29 . Th. II with 2 (m1, m2) medio-medial, 3 (m4, m 4i, m4p) medio-lateral and 15 posterior mac; p4 and p5 as mac. Th. III with 18 mac; m 5i and a 6i as mac. Metatrochanteral organ with about 30 smooth spiny chaetae. Unguis with 3 inner teeth, all minute; inner paired and distal ones 0.5 and 0.8 distance from base, respectively. Unguiculus lanceolate. Tenent hair subequal to unguis in length ( Fig. 30 ).

Abd. IV 2.2 times as long as Abd. III along dorsal midline. Abd. I with 3 (m2−4) central mac. Abd. II with 3 (a2, m3, m3e) central and 1 (m5) lateral mac. Abd. III with 2 (a2, m3) central and 4 (am6, pm6, p6, m7) lateral mac. Abd. IV with 7 central mac. Accessory mic of bothriotrichal complexes on Abd. II −IV strongly modified or fan-shaped. Ventral tube anteriorly with 3 large ciliate chaetae and several ciliate chaetae on each side ( Fig. 31 ); posterior face and lateral flap not clearly seen. Distal smooth part of dens 1.86−2.00 times mucro in length ( Fig. 32 ).

Remarks. We provide here complete dorsal cephalic and body chaetotaxy based on paratypes of W. bartkei . Fresh material is needed for a fuller description. Willowsia bartkei is most similar to W. guangxiensis Shi & Chen, 2004 from Guangxi Province, South China in having transverse bands on Abd. I to III, scale sculpture with short striations, abundant spiny chaetae (>30) on the trochanteral organ, and in the chaetotaxy of Abd. III. It differs from the latter in having a posterior patch of dark pigment on Abd. IV, unilobed Ant. IV apical bulb, scale distribution (absent on antennae), lanceolate unguiculus, much longer distal smooth part of dens, 3+3 mac on Abd. I, 3+3 inner mac on Abd. II, and fewer inner mac (7+7) on Abd. IV.

Figures

FIGURES 27 – 32. W. bartkei: 27, body scales; 28, dorsal cephalic chaetotaxy; 29, chaetotaxy of Th. II – Abd. IV; 30, hind claw; 31, anterior face of ventral tube; 32, mucro.