Tomocerus deharvengi, Yu, Daoyuan & Li, Youbang, 2016

Yu, Daoyuan & Li, Youbang, 2016, New troglomorphic species of Tomocerus with well-developed postantennal organs (Collembola: Tomoceridae), Zootaxa 4162 (2), pp. 361-372 : 365-368

Tomocerus deharvengi sp. nov.

Figs 1 C, 4, 5

Type material. Holotype female adult, on slide. Collected in Lengshuicao Cave , Shuinongtun , Nabu Village , Baisheng Township , Napo County, Baise, Guangxi Province, China, 6.X.2015, by Youbang Li, Zhouquan Wei and Yueting Feng . Paratypes four female adults on slides, 10 in 99% alcohol, same data as holotype. All types in NJAU .

Description. Body length 4.1–4.8mm. Body with uniform light to dark grey pigment, with unpigmented patches. Clypeus, antero-dorsal area of head, Ant.I and Ant. II darker. Eye patches black ( Fig. 1 C).

Intact antenna not seen, longest regenerated antenna approximately 1.4 times as long as body. Antenna length ratio as I:II:III+IV= 1.0:1.4:22.0–24.0. Both dorsal and ventral sides of Ant. I and Ant. II scaled, Ant. III dorsobasally with several scales. PAO with oval central pit and broad vesicle, long diameter of central pit subequal to that of eye ( Fig. 4 A). Eyes 6+6, relatively small. Labral chaetae formula as 6/5, 5, 4. Distal edge of labrum with four curved spines each setting on a papilla-like structure ( Fig. 4 B). Mandibular head asymmetrical, the left one with 4 teeth and the right one with 5, left molar plate distally with a tapered tooth ( Fig. 4 C). Basal teeth of maxillary lamella 5 elongated, without beard-like appendage ( Fig. 4 D). Maxillary outer lobe with trifurcate palp ( Fig. 4 E), one basal chaeta and 4 sublobal hairs. Both dorsal and ventral sides of head scaled. Cephalic dorsal macrochaetotaxy: anterior area: 2; interocular area: 2, central uneven macrochaeta absent; postocular area: 2+2; posterior area: 1+1. Posterior margin of head with 70–80 small chaetae ( Fig. 4 F). Mentum with 5 chaetae, submentum with numerous chaetae.

Pattern of body chaetotaxy as in Fig. 4 G. Number of bothriotricha as 2, 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 file of macrochaetae behind anterior margin. Number of macrochaetae or large mesochaetae in the posterior row as 3, 3/ 3, 3, 4, 2, 4 from Th. II to Abd.V. Th. II with two central macrochaetae, posterior one near pseudopore; Abd.III with two anterior macrochaetae; Abd.IV with one antero-lateral macrochaeta; Abd.VI with numerous chaetae of different sizes. Most mesochaetae laterally and posteriorly on terga. Pseudopores near the axis of terga, number of them as 1, 1/ 1, 1, 1, 1, 0, 0.

Trochantero-femoral organ with 1, 1 small slender chaetae. Front, middle and hind tibiotarsus ventrally with 4– 5, 4–5, 5–6 spine-like chaetae ( Fig. 4 H). Each tibiotarsus with a distal whorl of 11 chaetae, ventral six as ordinary chaetae, dorsal five modified: morphology of tenent hair unknown, its sockets slightly larger than those of guard chaetae; a pair of accessory chaetae small, subequal to pretarsal chaetae; one pair of guard chaetae slender ( Fig. 5 A). Unguis slender, with baso-internal ridges about 1/3 distance from base; lateral teeth pointed, of moderate size. Inner edge of unguis with one basal and one central minute teeth. Unguiculus slender, about 0.5–0.75 times as long as unguis, its inner edge with one large corner tooth. Pretarsus chaetae 1+1 ( Fig. 5 B).

Ventral tube with scales on both anterior and posterior faces, lateral flaps unscaled, anterior face with about 40–50 chaetae on each side, posterior face with 90–120 chaetae, each lateral flap with 95–110 chaetae. Rami of tenaculum with 4+4 teeth, anterior face with 6–7 small chaetae and without scale ( Fig. 5 C). Furca length ratio as manubrium:dens:mucro=3.0–3.5:4.5–5.4:1.0. Manubrium ventrally scaled, without chaetae, laterally with large round scales and 9–11 chaetae, proximal 1–2 small, distal ones large, moderately developed; each dorsal chaetal stripe with 250–300 chaetae of different sizes and a few randomly distributed inner scales, prominent chaetae 2+2, pointed; pseudopores 13–16 on each side ( Fig 5 D); external corner chaeta as large as moderate sized mesochaetae in chaetal stripe ( Fig. 5 E). Dens basally with a pointed prominent dorsal chaeta, without large modified inner scale or strong outer chaetae. Dental spines formula as 3–4/3–4, I, 1, I; all spines with numerous small to moderate sized denticles ( Fig. 5 F). Dens dorsally with ordinary chaetae and feather-like chaetae, ventrally covered by scales. Mucro elongated and multi-setaceous; both basal teeth with proximal lamellae, outer tooth with relatively large toothlet; apical and subapical tooth subequal; structure of dorsal lamellae of Tomocerus type, outer lamella with 5– 7 moderate sized intermediate teeth ( Fig. 5 G).

Etymology. Named after the French collembologist and speleologist Dr. Louis Deharveng.

Remarks. Tomocerus deharvengi sp. nov. is congruent with T. postantennalis in most characters, especially in the habitus, the PAO, the prelabral chaetae, the body chaetotaxy, the claw and the dental spines. However, they are still considerably different in several characters: T. postantennalis has four macrochaetae in the anterior area of head, whereas T. deharvengi sp. nov. has only two; with the same or larger body size, the latter species has less pseudopores on manubrium and less dental spines on the middle subsegment of dens. Besides, the PAO in T. deharvengi sp. nov. has a broad outer vesicle which is not seen in Tomocerus postantennalis , but considering the vesicle may be eversible, this difference can not be used in diagnosis at present.

Figures

FIGURE 4. Tomocerus deharvengi sp. nov. (A) left PAO and eyes (dorsal view); (B) labrum (anterior view); (C) apices of mandibular heads (dorsal view); (D) lamella 5 of maxillary head (dorsal view); (E) palp of maxillary outer lobe (dorsal view); (F) cephalic dorsal chaetotaxy (dorsal view); (G) dorsal chaetotaxy of Th. II – Abd. V (dorsal view); (H) tibiotarsi (lateral view). Scale bars: A, B, C, E, 50 µm; D, 15 µm; H, 200 µm.

FIGURE 5. Tomocerus deharvengi sp. nov. (A) apex of tibiotarsus and base of claw (dorsal view); (B) front claw (lateral view); (C) tenaculum (anterior view); (D) right side of manubrium (dorsal view, T-shaped mark: socket of scale, same as below); (E) disto-external corner of manubrium (dorsal view); (F) spines and prominent dorso-basal chaeta on dens (dorsal view); (G) mucro (inner view). Scale bars: A, B, C, E, G, 50 µm; D, F, 100 µm.

FIGURE 1. A and B, Tomocerus dong sp. nov. (A) appearance in alcohol (lateral view); (B) left side of manubrium and base of dens (dorsal view, arrows pointing to prominent chaetae); C, Tomocerus deharvengi sp. nov. (C) appearance in alcohol (lateral view); D and E, Tomocerus cthulhu sp. nov. (D) appearance in alcohol (lateral view); (E) ventral tube (lateral view). Scale bars: A, C, D, 1 mm; B, 100 µm; E, 200 µm.