Homidia sichuanensis Jia, Zhang & Jordana

Jia, Shao-Bo, Zhang, Yu-Ping, Zhao, Yan & Jordana, Rafael, 2010, A new species of Homidia from China, and description of the dorsal chaetotaxy of all Chinese Homidia species (Collembola: Entomobryidae), Zootaxa 2683, pp. 23-34 : 24-29

Homidia sichuanensis Jia, Zhang & Jordana sp. nov.

Figs 1 –16 Tab. 1, 2

Type material. Holotype male, paratypes 3 males and 42 females. CHINA: Sichuan Province: Emei Mountain: near Baoguo Monastery, alt. 480m, 24.v.2002, collected by Chen Jian-Xiu, collection number C9131–D. Deposited in the Department of Biology, Nanjing University. And 16 specimens (3 males & 13 females) from the campus of Guizhou University, Guizhou Province, alt. 1000m, 19.iv.2007, coll. Yan Yi, collection number S0071, kept in School of Life Sciences, Liaocheng University. 1 paratype is deposited in the Museum of Zoology, University of Navarra.

Description. Maximum body length 3.25 mm (Holotype 3.1 mm).

Color and pattern. Ground color pale yellowish or whitish. Eye patches dark blue to black. Frontal and inter-antennal areas of head dark blue; narrow blue pigment line present behind eyes and reach thoraces along lateral borders of head. Antennal segments I & II lightly pigmented, deeply pigmented on Ant. III and IV. Terga of Th. II and III with median large dark spots and dark lateral margins. Abd. III largely dark, with paler areas near lateral margins. Abd. IV with 2 transverse bands, one made of scattered pale blue pigment on the anterior 1/3 and a wide deep blue band on the posterior 1/4. Latero-posterior margins of Abd. IV dark. Lateral sides of Abd. V pale blue. Abd. VI without pigment. Hind leg with dark pigment on trochanter and femur, other leg segments sparsely pigmented ( Fig. 1 ).

Head. Eyes 8+8, ocelli A–F subequal, G and H much smaller and sometimes difficult to see. 3 small setae surrounded by eyes D–H ( Fig. 2 ). Antennae 2.7–4.1 times as long as cephalic diagonal; ratios of Ant. I–IV as 1/1.2–1.8/1–1.5/1.5–3.3. Ant. IV with bilobed apical vesicle ( Fig. 3 ).

Chaetotaxy. Dorsal chaetotaxy of head ( Jordana & Baquero 2005; Soto-Adames 2008) with 3 setae in area H1 (An2, An3a, An3), 1 seta in area H2 (A5), 3 setae in area H4 (S1, S3, S4), and 2 setae in area H5 (Ps2, Ps5); seta S’0 in area H3 absent ( Fig. 2 ,). Head macrochaetotaxy formula: 3–1–0–3–2. Labral setal formula as 4/5,5,4 ( Fig. 4 ). Seta a0 and a1 subequal but slightly longer than seta a2; seta b0 and b1 subequal but slightly longer than seta b2; c1 and b2 subequal but slightly longer than c2; a1, a2 and a3 longer than other setae ( Fig. 4 ). Setal formula of labial triangle as M, R, E, L1, L2; seta R 0.66–0.75 times as long as M; E smooth (mostly), or both E and L1 smooth ( Fig. 5 ). All postlabial setae (see Chen & Christiansen 1993) ciliate, H1, H2, H3, H4 subequal but slightly longer than G1, G2, G3, G4. Setae G1 slightly longer than G2, G3 and G4; G2 and G4 subequal but slightly shorter than G3. Setae X, X2, X3 subequal but slightly shorter than X4; these slightly shorter than other setae. ( Fig. 5 ). None of the setae expanded or leaf-like.

Dorsal thoracic chaetotaxy as in Fig. 6 . Th. II with 4 medio-medial (m1, m2, m 2i, m 2i 2), 5 mediosublateral (m4, m 4i, m4p, a5, m5) and 28–32 posterior macrochaetae. Formula of T1–T2 areas on Th. II: 4–5. Th. III with about 35 macrochaetae, macrochaeta p4 always present.

Dorsal chaetotaxy of Abd. I–III as in Fig. 7 . Abd. I with 8–12 (mostly 9–11) macrochaetae (a2, a3, a5, m2, m 2i, m3, m4, m 4i, m4ip, m5) on each side; Abd. II with 6 (7) macrochaetae (a2, a3, m3, m3e, m3ea, m3ep often absent) on each side. A1–A2 areas with 2–4 (3) macrochaetae; Abd. III with 1 (m3) central and 4 lateral macrochaetae (m6, pm6, m7, p6) on each side. A3–A5 areas with 0–0–1 macrochetae. Dorsal chaetotaxy of Abd. IV and V shown in Fig.8 . Abd. IV with 8–14 anterior and 6–7 posteromedial macrochaetae on each side. Areas A6–A10 with formula 0–8(12)–0–3–2(3) macrochaetae (area A7 with 8–12, area A9 with Ai1, B5 and Ae5 macrochaetae and area A10 with B6, Ae8 and A6 macrochaetae) Ae8 frequently asymmetric. Abd.V with about 16 macrochaetae on each side (m5a, p0 always present). (see Table 1)

Legs. Coxal macrochaetal formula as 3/4 (5) +2, 3/4+2, some mesochaetae also present on coxa of leg III ( Fig. 9 ). Trochanteral organ developed only in the hind leg, composed of 50–84 stiff, smooth setae, 18–20 of them arranged in arms, 32–64 between arms (Fig. 10). Inner tibiotarsal differentiated setae slightly ciliate and clearly different from other normal coarsely ciliate setae. Tenent hair strongly clavate and slightly longer than inner edge of unguis. Unguis with 3 small inner teeth, basal paired teeth subequal. Outer edge of unguiculus smooth without large tooth (Fig. 11).

Ventral tube. In addition to numerous ciliate setae of different sizes, ventral tube anteriorly with 4+4 ciliate macrochaetae, a line connecting proximal (Pr) and external-distal (Ed) ones oblique to median furrow (Fig. 12); posteriorly with numerous ciliate setae of different sizes and 2–8 (mostly 5–6, median 1 or 2 setae much shorter than others) smooth subapical setae of different sizes (Fig. 13); lateral flap with 7–14 ciliate and 6–8 smooth setae (Fig. 14).

Furcula. Ratios of Manubrium: (Dens + Mucro) = 1: 1.52 in holotype. Basal three fourth of dens with 28– 75 (mostly 40–70) spines along inner edge in adults. Dental basal setae bs1 & bs2 multilaterally ciliate, bs1 much thicker and longer than bs2; proximal-internal seta (pi) ciliate, slightly longer than bs2 (Fig. 15). Ante– apical teeth of mucro bigger than apical.

Abdomen. Male genital plate as in Fig. 16.

Ecology. Found in litter or under bricks and stones in bamboo, deciduous or mixed forests.

Etymology. The new species is named after the type locality––Sichuan Province, China.

Discussion. Concerning chaetotaxy (Table 1), the closest species are H. huashanensis and H. phjongiangica from which the new species differs in two chaetotaxy characters, A4 and A10, 1 and 4 macrochaetae respectively instead of 0 and 3 on the new species. Homidia sichuanensis is markedly different from other forms in its color pattern, number of dental spines, and claw structure. The new species has a very particular chaetotaxy in Abd. III (0–0–1) shared only with H. formosana , H. cingula , H. heugsanica Lee & Park, 1984 and H. minuta Kim & Lee, 1995 , but it differs from these species in the chaetotaxty of Abd. IV, number of dental spines and color. The new species is close to H. ziguiensis in color pattern. However, it differs from the latter by absence of unusual expanded or leaf-like setae of the mentum and 6 other chaetotaxy characters (Table 1). The new species is also close to H. koreana Lee & Lee, 1981 in setae formula of labial base and the chaetotaxy on Abd. IV. However, it differs from the latter by color pattern, the coxal macrochaeta formula and chaetotaxy of Abd. III. A diagnostic table for seven closely related Homidia species is provided (see Table 2)

FIGURES 10–16. Homidia sichuanensis sp. nov.: 10, trochanteral organ; 11, hind foot complex; 12, anterior face of ventral tube; 13, posterior face of ventral tube; 14, lateral flap of ventral tube (left side); 15, basal part of dens (bs1 and bs2—basal setae, pi—proximal-internal seta); 16, male genital plate.

Figures

FIGURE 1. Homidia sichuanensis sp. nov.: 1, habitus (1 a, color pattern; 1 b, drawing of lateral view).

FIGURES 2 – 5. Homidia sichuanensis sp. nov.: 2, dorsum of head; 3, antennal apical bulbs; 4, labrum; 5, labial and postlabial chaetotaxy (left side).

FIGURES 6 – 9. Homidia sichuanensis sp. nov.: 6, dorsal chaetotaxy of thorax; 7, dorsal chaetotaxy of Abd. I – III; 8, dorsal chaetotaxy of Abd. IV – V; 9, macrochaetae of coxae (right legs, dorsal view; a. leg I, b. leg II, c. leg III).