Tomocerus dissimilis, Yu, Daoyuan, Ding, Yinhuan & Ma, Yitong, 2017

Yu, Daoyuan, Ding, Yinhuan & Ma, Yitong, 2017, Revision of Tomocerus similis Chen & Ma, with discussion of the kinoshitai complex and the distal tibiotarsal chaetae in Tomocerinae (Collembola, Tomoceridae), Zootaxa 4268 (3), pp. 395-410 : 403-406

Tomocerus dissimilis sp. nov.

Figs 1 C, 6, 7

Type material. Holotype male adult on slide. Monkey Valley , Yellow Mountain, Huangshan, Anhui Province, China, 118°8'47"E, 30°4'58''N, alt. 578m, 2.iii.2016, by Daoyuan YU (No. 2016HS-1) . Paratypes 1 male and 4 female adults on slides, 8 in alcohol, same data as holotype. Two paratypes in alcohol in NTU, other types in NJAU .

Description. Body length 2.5–2.9mm. Body ground colour brownish yellow, with diffuse dark pigment on head, thorax and legs. Anterior area of head and Th. II slightly darker. Antennae dark purple. Eye patches black. ( Fig. 1 C).

Antennae short, 0.42–0.50 times as long as body. Length ratio of Ant I:II:III:IV= 1.0:1.3–1.6:5.9–6.2:1.5–1.9. Dorsal side of Ant. I and Ant. II scaled, Ant. III and Ant. IV unscaled. PAO not seen. Eyes 6+6. Mouthparts of Tomocerus type. Both dorsal and ventral sides of head scaled. Cephalic dorsal macrochaetotaxy: anterior area: 2, 2; interocular area: 2, 6, central unpaired macrochaeta absent; postocular area: 2+2; posterior area: 0. Posterior margin of head with 40–50 small chaetae on each side ( Fig. 6 A). Mentum with 5 chaetae, submentum with numerous chaetae.

Pattern of body chaetotaxy as in Fig. 6 B. Bothriotricha 1, 1/ 0, 0, 1, 2, 0, 0 on Th. II–Abd. VI. Macrochaetae densely arranged along anterior margin of Th. II (not shown in figure). Th. II with an irregular row of macrochaetae behind anterior margin. Number of macrochaetae or large mesochaetae in the posterior row as 3, 3/ 3, 3, 4, 3, 4 from Th. II to Abd. V. Th. II with four central and one lateral macrochaetae, postero-central one near pseudopore; Th. III with anterior macrochaeta; Abd. III with two anterior macrochaetae; Abd. IV with one lateral macrochaeta; Abd. VI with numerous chaetae of different sizes. Mesochaetae most abundant laterally and posteriorly on terga. Pseudopores near the axis of terga, 1, 1/ 1, 1, 1, 1, 0, 0 from Th. II to Abd. VI.

Trochantero-femoral organ with 1, 1 small slender chaetae. Anterior, mid and hind tibiotarsi ventrally with 0, 0, 2 spine-like chaetae ( Fig. 6 C). Each tibiotarsus with a distal whorl of 11 chaetae, ventral 6 as ordinary chaetae, dorsal 5 modified: tenent hair short, thin and pointed on front legs and clavate on middle and hind legs, clavate tenent hair about 0.6 times as long as inner edge of unguis; two accessory chaetae small, subequal to or slightly longer than pretarsal chaetae; two guard chaetae slender and longer than clavate tenent hair, about 0.75 times as long as unguis. Unguis slender, with baso-internal ridges about 1/3 distance from base; lateral teeth pointed, relatively small. Inner edge of unguis with distinct basal tooth, large sub-basal tooth and 0–2 small distal teeth. Unguiculus lanceolate, about 0.55–0.6 times as long as unguis, its inner edge with 0–1 small tooth. Pretarsus chaetae 1+1 ( Fig. 6 D, E).

Ventral tube scaled only on anterior face. Anterior face with 20–25 chaetae on each side, posterior face with approximately 75 chaetae, each lateral flap with 40–50 chaetae. Rami of tenaculum with 4+4 teeth, anterior face with 1 small chaeta and without scales ( Fig. 7 A). Ratio manubrium:dens:mucro=2.4–2.5:2.6–2.9:1.0. Manubrium ventrally scaled and without chaetae, laterally with large round scales and 9–10 chaetae on each side, proximal 2–3 chaetae small, distal ones strong; each dorsal chaetal strip with approximately 110 chaetae of different sizes; inner to each chaetal strip with a row of scales, running from base to the middle of manubrium; prominent chaetae 2+2, long, slender and pointed; pseudopores 7–10 on each side ( Fig 7 B); manubrial distal corner chaeta as microchaeta ( Fig. 7 C). Dens basally with a pointed prominent dorsal chaeta, without large modified inner scale or strong outer chaetae. Dental spine formula as 3–5/1–2, II; all spines basally with several moderate to large sized denticles. Dens dorsally with ordinary chaetae and feather-like chaetae, ventrally with dense scales and several apical chaetae; distal subsegment with inner longitudinal row of short slender chaetae ( Fig. 7 D). Mucro elongated and multisetaceous; both basal teeth with proximal lamellae, outer basal tooth with a toothlet; apical tooth longer than subapical one; structure of dorsal lamellae of Tomocerus type, outer lamella with 1 moderate sized intermediate teeth ( Fig. 7 E).

Etymology. Specific name from the Latin word dissimilis , meaning not similar.

Ecology. In humus layer of mixed forest.

Remarks. Tomocerus dissimilis sp. nov. is characterised by the different forms of tenent hairs on different legs. Also, T. dissimilis sp. nov. differs from T. kinoshitai and T. persimilis sp. nov. in the absence of central macrochaeta on head. The unguis are either without or with 1–2 small distal teeth, and, if present, the most proximal distal tooth is stronger than the most distal one. In the old material, 7 paratypes (No. 8164, 8169, 8172ab, 8222ab, 8344) were collected from Yellow Mountain. The specimens 8164, 8169, 8172b and 8222a comply with the characteristics of T. dissimilis sp. nov. in cephalic chaetotaxy and ungual teeth, while specimens 8172a, 8222b and 8344 appear to be a different form, but the type of tenent hairs in the old specimens are too obscure to determine this definitely.

Figures

FIGURE 1. Colour photographs of the species in alcohol (lateral view) (A) Tomocerus similis; (B) Tomocerus persimilis sp. nov.; (C) Tomocerus dissimilis sp. nov. Scale bars: 1 mm.

FIGURE 6. Tomocerus dissimilis sp. nov. (A) cephalic dorsal chaetotaxy (dorsal view); (B) dorsal chaetotaxy of Th. II – Abd. V (dorsal view); (C) hind tibiotarsus (lateral view); (D) front claw (lateral view); (E) middle claw (lateral view). Symbols as for Figure 2.

FIGURE 7. Tomocerus dissimilis sp. nov. (A) tenaculum (anterior view); (B) left side of manubrium (dorsal view); (C) distoexternal corner of manubrium (dorsal view); (D) spines, prominent dorso-basal chaeta and distal short slender chaetae on dens (dorsal view); (E) mucro (outer view). Symbols as for Figure 2.