Tomocerus nabanensis, Yu & Yang & Liu, 2018

Yu, Daoyuan, Yang, Xiaodong & Liu, Manqiang, 2018, Three new species of Tomocerus from tropical zone of China (Collembola, Tomoceridae), Zootaxa 4508 (2), pp. 225-236 : 232-233

Tomocerus nabanensis sp. nov.

Figs 1C , 6 , 7

Type material. Holotype: female on slide, Naban River National Nature Reserve , Xishuangbanna, Yunnan Province, China, 100°39'E, 22°8'N, alt. 1225 m, vii.2017, litters and humus, leg. Shengjie Liu (17BN1) . Paratypes: 3 females and 2 males on slides, 15 adults and juveniles in alcohol, same data as holotype. All types in NJAU .

Description. Body length 2.1–3.5 mm. General background colouration of body dirty brownish yellow, antero-lateral margin of thoracic terga darker. Ant. I and Ant. II distally with purple pigment, Ant. III and Ant. IV purple. Eye patch black. Purple pigment around antennal bases and mouthparts. All leg segments with diffuse purple pigment, tibiotarsi darker ( Fig. 1C ).

Antenna 0.8–1.0× length of body. Length ratio of Ant I:II:III:IV = 1.0:1.3–1.4:9.0–9.3:1.2–1.4. Cephalic dorsal macrochaetotaxy: anterior area: 2 (A2), 4 (A3, A5); interocular area: 2 (M2), 7 (S0, S2, S5, S 5i); postocular area: 2+2 (Pa5, Pa6); posterior area: 1+1 (Pa2). Posterior margin of head with 35–40 chaetae on each side ( Fig. 6A ).

Pattern of body chaetotaxy as in Fig. 6B . Th. II with macrochaetae a3, a4a and a5a behind anterior marginal macrochaetae cluster; central area with macrochaetae a2, a5, m1, m2 (rarely absent) and m3.

Trochantero-femoral organ with 1, 1 slender chaetae. Tibiotarsi I, II, III ventrally with 7–9, 6–9, 7–9 strong chaetae, 2–4, 2–4, 3–5 of them blunt ( Fig. 6C ). Tenent hair 0.64–0.74× length of inner edge of unguis; anterior accessory chaeta shorter than pretarsal chaetae, posterior accessory chaeta longer than pretarsal chaetae; guard chaetae subequal to or slightly longer than tenent hair. Unguis slender, with baso-internal ridges about 1/4–1/3 distance from base; lateral teeth pointed, of moderate size. Inner edge of unguis with basal tooth and more distal tooth at about 1/3 distance from base. Unguiculus lanceolate, about 0.58–0.71× length of unguis, its inner edge with one tooth ( Fig. 6D ).

Ventral tube scaled on both faces. Anterior face with 20–30 chaetae on each side, posterior face with 40–90 chaetae, each lateral flap unscaled, with 45–95 chaetae. Anterior face of tenaculum with 5–11 chaetae and without scales ( Fig. 6E ). Ratio of manubrium:dens:mucro = 2.6–3.0:3.5–3.9:1.0. Manubrium ventrally scaled without chaetae; laterally with large round scales and 10 chaetae, proximal 1–2 chaetae slender and almost smooth, distal chaetae strong and slightly serrated; each dorsal chaetal strip with 95–145 chaetae of different sizes, an irregular row of scales from base to about 2/3 length of manubrium along inner edge, and 6–14 pseudopores on lateral side; a pair of pointed prominent chaetae near distal end of manubrium ( Fig. 7A ); distal corner chaeta as large as small mesochaetae in chaetal strip. Dens basally with pointed prominent dorsal chaeta. Dental spine formula as 4–5/3–7, 1, 1, 1 ( Fig. 7B ); denticles on spines unevenly distributed, all spines with basal moderate to large denticles, large spines ventrally with additional small denticles ( Fig. 7C ). Mucro with 3–7 intermediate teeth ( Fig. 7D ).

Etymology. Named after type locality Naban River National Natural Reserve.

Habitat. Mixed forest, in leaf litters and humus.

Remarks. Tomocerus nabanensis sp. nov. is characterised by absence of cephalic macrochaeta Pp3 and mesothoracic macrochaetae a4 and m4, presence of two inner teeth on the unguis, 1+1, 1 pointed prominent chaetae on the furca, dorsal scales on the manubrium, a small spine between two large distal spines and uneven distribution of denticles on the dental spines. The new species resembles cave species T. postantennalis , Tomocerus dong Yu & Li, 2016 and Tomocerus deharvengi Yu & Li, 2016 in dental spine formula and number of the ungual teeth, but differs from the latter species in absence of the large PAO, different pattern of the dorsal chaetotaxy and presence of stronger tenent hairs. The general appearance and dental spine formula of the new species are also similar to those of T. folsomi , but the latter has more teeth on the unguis and smaller denticles on dental spines ( Denis 1929). Critical characters discriminating T. nabanensis sp. nov. from similar species are listed in Table 1. Malformed dental spine formulas are found in one female, with 9/4, 1, 3, 1 on the right side and 6/7, 1, 1 on the left side, and in this case proximal spines on both sides are irregularly arranged, distal small spines on the right side are arranged in two rows.

Figures

FIGURE 1. Photographs of the species in alcohol (lateral view) (A) Tomocerus tropicus sp. nov.; (B) Tomocerus nan sp. nov.; (C) Tomocerus nabanensis sp. nov. Scale bars: 1 mm.

FIGURE 6. Tomocerus nabanensis sp. nov. (A) cephalic dorsal chaetotaxy (dorsal view); (B) dorsal chaetotaxy of Th. II–Abd. V (dorsal view, open circle marked with asterisk—chaeta absent in some specimens); (C) tibiotarsi I, II and III (lateral view); (D) hind claw complex (posterior view, ao—accessory chaeta on other side); (E) tenaculum (anterior view). Symbols as for Figure 2.

FIGURE 7. Tomocerus nabanensis sp. nov. (A) left side of manubrium (dorsal view); (B) basal part of dens (dorsal view); (C) large and small dental spines; (D) left mucro (inner view). Symbols as for Figures 2 and 3.