Tomocerus paraspinulus, Gong & Qin & Yu, 2018

Gong, Xin, Qin, Chunyan & Yu, Daoyuan, 2018, Two new species of Tomocerus ocreatus group with a single large distal dental spine (Collembola, Tomoceridae), Zootaxa 4514 (2), pp. 273-282 : 278-281

Tomocerus paraspinulus sp. nov.

Figs. 1B , 4 , 5

Type material. Holotype: male on slide, near entrance of Baixiong Valley , Wanglang National Nature Reserve, Pingwu County, Sichuan Province, China, 104°1′12″E, 33°0′8″N ( WGS84 ), alt. 2845m, 29.vii.2017, leg. Daoyuan Yu and Qibao Yan (17SC9) . Paratypes: 5 females on slides, 11 in alcohol, same data as holotype. All types deposited in NJAU .

Description. Body length 3.2–4.1 mm (average 3.7, 4 specimens). Background body colour light yellow. Ant. I antero-laterally with small purple patches, Ant. II distally with diffuse purple pigment, Ant. III and Ant. IV purple. Antennal base with purple ring. Eye patch black, diffuse light purple pigment around eye and on clypeus. Antero-lateral side of subcoxae and coxa I with purple pigment. Tibiotarsi with light purple pigment ( Fig. 1B ).

Intact four-segmented antennae 0.9–1.0× length of body (average 0.95, 3 specimens). Length ratio of Ant I:II:III:IV = 1.0:1.2–1.4:9.5–10.2:1.1–1.2. Ant. III unscaled or with 1–2 basal scales. 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: 3+3 (Pa2, Pp3, Pe3). Posterior margin of head with 25–30 chaetae on each side ( Fig. 4A ).

Pattern of body chaetotaxy as in Fig. 4B . Number of macrochaetae or large mesochaetae in posterior row as 3 (p2, p3, p4), 3 (p1, p3, p5)/ 3 (m2, m3, m4), 3 (m2, m3, m4), 4 (p1, p3, p6, p7), 2 (p6, p7), 4 (m2, m3, m5, m6) from Th. II to Abd. V. Th. II with macrochaetae a3, a4, a4a and a5a behind anterior marginal macrochaetae cluster; central macrochaetae a2, a5, m1, m2 and m3 arranged in triangle, m4 lateral to m2; m3 and m4 occasionally absent. Th. III with anterior macrochaeta a4; Abd. III with two anterior macrochaetae m3 and m6; Abd. IV with antero-lateral macrochaeta m6; Abd. VI with numerous chaetae of different sizes.

Trochantero-femoral organ with 1, 1 slender chaetae, femoral chaeta longer ( Fig. 4C ). Tibiotarsi I, II, III ventrally with 7–8, 7–9, 8–9 strong chaetae, 4–7, 6–8, 6–9 of them blunt ( Fig. 4D ). Tenent hair 1.0–1.2× length of inner edge of unguis (average 1.1, 3 specimens); anterior accessory chaeta weaker than pretarsal chaetae, posterior accessory chaeta stronger than pretarsal chaetae; guard chaetae 0.9× length of 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 4–6 (average 5, 6 specimens) more distal teeth, sub-basal tooth larger. Unguiculus lanceolate, about 0.55–0.75× length of unguis (average 0.67, 4 specimens), its inner edge with one tooth ( Fig. 4E ).

Ventral tube scaled on both faces. Anterior face with 35–50 (average 41, 4 specimens) chaetae on each side, posterior face with 85–100 (average 93, 4 specimens) chaetae, each lateral flap with 100–136 (average 120, 4 specimens) chaetae, without scale. Anterior face of tenaculum with 14–18 (average 16, 6 specimens) chaetae and without scales ( Fig. 4F ). Ratio manubrium:dens:mucro = 2.8–3.3:3.2–4.1:1.0. Manubrium ventrally scaled without chaetae; laterally with large round scales and 9–10 chaetae, proximal 1–2 chaetae slender, distal chaetae strong; each dorsal chaetal strip with 160–240 (average 185, 5 specimens) chaetae of different sizes, an irregular row of scales from base to 2/3 – 3/4 (average 7/10, 6 specimens) length of manubrium along inner edge, and 9–13 (average 11, 6 specimens) pseudopores on lateral side; prominent chaetae 1+1, blunt, at about 2/3 – 3/4 (average 7/ 10, 6 specimens) length from base of manubrium ( Fig. 5A ); external distal corner chaeta as large as small mesochaetae in chaetal strip ( Fig. 5B ). Dens basally with prominent blunt dorsal chaeta. Dental spine formula as 3– 5/5–8, 1, sizes of spines gradually increase on basal subsegment ( Fig. 5C ); spines with almost evenly distributed numerous small denticles ( Fig. 5D ). Mucro with 4–7 (average 5, 6 specimens) intermediate teeth ( Fig. 5E ).

Etymology. Combination of the Ancient Greek word pará: beside, near, and the specific name of T. spinulus .

Habitat. Living in mosses and lichens on trunks of fir tree.

Remarks. Tomocerus paraspinulus sp. nov. resembles T. spinulus in having a single large distal spine on the dens and almost evenly distributed small denticles on the dental spines, but differs from the latter mainly in having longer intact antenna, more chaetae on the tenaculum and blunt prominent chaetae on the manubrium and dens ( Table 1). In addition, in the new species two accessory chaetae of the tenent hair are unequal in size, and the prominent manubrial chaeta is more distally positioned than in T. spinulus . Tomocerus paraspinulus sp. nov. is also similar to T. pseudospinulus sp. nov., but differs mainly in having longer intact antenna, prominent blunt manubrial chaeta and smaller denticles on the dental spines ( Table 1). The type locality of Tomocerus paraspinulus sp. nov. is at the eastern edge of Qinghai-Tibetan Plateau, more than 1100 km away from those of T. pseudospinulus sp. nov. and T. spinulus , with about 2000 m altitudinal difference.

Figures

FIGURE 1. Photographs of the species in alcohol (lateral view) (A) Tomocerus pseudospinulus sp. nov.; (B) Tomocerus paraspinulus sp. nov. Scale bars: 1 mm.

FIGURE 4. Tomocerus paraspinulus sp. nov. (A) cephalic dorsal chaetotaxy (dorsal view); (B) dorsal chaetotaxy of Th. II– Abd. V (dorsal view, open circle marked with asterisk—chaetae absent in some specimens); (C) trochantero-femoral organ (inner view); (D) tibiotarsus I, II and III (lateral view); (E) hind claw complex (lateral view, ao – accessory chaeta on other side); (F) tenaculum (anterior view). Symbols as for Figure 2.

FIGURE 5. Tomocerus paraspinulus sp. nov.; (A) left side of manubrium (dorsal view); (B) distal area of manubrium (dorsal view); (C) basal part of dens (dorsal view); (D) dental spine; (E) left mucro (inner view). Symbols as for Figure 2 and 3.