Tomocerus persimilis, 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 : 401-403

Tomocerus persimilis sp. nov.

Figs 1 B, 4, 5

Type material. Holotype male adult on slide. Purple Mountain , Nanjing, Jiangsu Province, China, 118°53'6.7"E, 32°3'40.4''N, alt. 117m, 15.iii.2015, by Chunyan Qin and Daoyuan YU (No. NJ 2015ZJ-1) . Paratypes 4 female adults on slides, 5 in alcohol, same data as holotype. Two paratypes in alcohol in NTU, other types in NJAU .

Description. Body length 2.7–3.8mm. Body ground colour brownish yellow, with diffuse dark pigment on head, thorax and legs. Anterior area of head and Th. II darker. Antennae dark purple. Eye patches black. ( Fig. 1 B). Antennae short, 0.37–0.42 times as long as body. Length ratio of Ant I:II:III:IV= 1.0:1.4–1.6:5.4–6.0:1.7–2.0. 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, 7, central unpaired macrochaeta present; postocular area: 2+2; posterior area: 0. Posterior margin of head with 40–50 small chaetae on each side ( Fig. 4 A). Mentum with 5 chaetae, submentum with numerous chaetae.

Pattern of body chaetotaxy as in Fig. 4 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 a 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. 4 C). Each tibiotarsus with a distal whorl of 11 chaetae, ventral 6 as ordinary chaetae, dorsal 5 modified: tenent hair clavate on all legs, thin and short, about 0.58–0.75 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 long, subequal to or longer than tenent hair, about 0.75–1.0 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 2–4 small but distinct distal teeth. Unguiculus lanceolate, about 0.55–0.63 times as long as unguis, inner edge with 1–2 small teeth. Pretarsus chaetae 1+1 ( Fig. 4 D).

Ventral tube scaled only on anterior face. Anterior face with approximately 20 chaetae on each side, posterior face with approximately 70 chaetae, each lateral flap with 50–60 chaetae. Rami of tenaculum with 4+4 teeth, anterior face with 1 small chaeta and without scales. Ratio manubrium:dens:mucro=2.3–2.6:2.9–3.2:1.0. Manubrium ventrally scaled and without chaetae, laterally with large round scales and 10 chaetae on each side, proximal 1–3 chaetae small, distal ones strong; each dorsal chaetal strip with 110–150 chaetae of different sizes; inner to each chaetal strip with a narrow band of scales, running from base to the middle of manubrium; prominent chaetae 2+2, long, slender and pointed; pseudopores 10–15 on each side ( Fig 5 A); manubrial distal corner chaeta as microchaeta ( Fig. 5 B). Dens basally with a pointed prominent dorsal chaeta, without large modified inner scale or strong outer chaetae. Dental spine formula as 3–4/1, 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. 5 C). Mucro elongated and multi-setaceous; both basal teeth with proximal lamellae, outer basal tooth with or without toothlet; apical tooth longer than subapical one; structure of dorsal lamellae of Tomocerus type, outer lamella with 2–4 moderate sized intermediate teeth ( Fig. 5 D).

Etymology. Specific name from the Latin word persimilis , meaning more similar.

Ecology. In humus layer of mixed forest.

Remarks. In the old material, the population from the Purple Mountain (“Mt. Zijing” in Chen and Ma 1997) is represented by paratype No. 8355. The old specimen was not well preserved and many characters are obscure, but some details on legs and furca are still recognisable. In “ paratype 8355” and the new specimens from the Purple Mountain, the ungual distal teeth are more distinct than in specimens from other localities, complying with the character of T. persimilis sp. nov. Compared to T. similis , T. persimilis sp. nov. is more similar to T. kinoshitai in the cephalic macrochaetotaxy. It differs from T. similis and T. dissimilis sp. nov. mainly in having central macrochaeta on the head and differs from T. kinoshitai in the absence of distal spine-like chaetae on the dens and in the presence of more ungual teeth. Also, T. persimilis sp. nov. is slightly darker and larger than both T. similis and T. dissimilis sp. nov.

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 4. Tomocerus persimilis sp. nov. (A) cephalic dorsal chaetotaxy (dorsal view); (B) dorsal chaetotaxy of Th. II – Abd. V (dorsal view); (C) hind tibiotarsus (lateral view); (D) hind claw (lateral view). Symbols as for Figure 2.

FIGURE 5. Tomocerus persimilis sp. nov. (A) right side of manubrium (dorsal view); (B) disto-external corner of manubrium (dorsal view); (C) spines, prominent dorso-basal chaeta and distal short slender chaetae on dens (dorsal view); (D) mucro (outer view). Symbols as for Figure 2.