Tomocerus dong Yu & Li, 2016, sp. nov.
Creators: name: Yu, Daoyuan
name: Li, Youbang
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Entognatha
Collembola
Tomoceridae
Tomocerus
Tomocerus dong

description: Tomocerus dong sp. nov.
Figs 1A, B, 2, 3
Type material. Holotype male adult, on slide. Collected in Cave I, Zhengjiatun Village, Nuxi Township, Jiangkou County, Tongren, Guizhou Province, China, 108°53'43.23"E, 27°52'12.59''N, alt. 397m, 30.vi.2014, by Mingyi Tian, Weixin Liu, Haomin Yin, Sunbin Huang & Xinhui Wang. Paratypes one female and two male adults on slides, 10 in 99% alcohol, same data as holotype. All types in NJAU.
Description. Body length 3.5–4.5mm. 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. 1A).
Body clothed densely by scales and various types of chaetae. Scales of typical morphology of Tomocerinae, with continuous longitudinal ridges on surface. Ordinary chaetae of different sizes. Microchaetae smooth and pointed. Macrochaetae and mesochaetae from slightly to strongly ciliated, some slightly ciliated mesochaetae appearing to be smooth under optical microscope. Most macrochaetae straight and subcylindrical, some macrochaetae on posterior segments of abdomen long, curved and acuminate. Mesochaetae acuminate, shorter and thinner than macrochaetae. S-chaetae subcylindrical, more hyaline than ordinary chaetae, as small as microchaetae except long ones on Abd. IV. Dorso-inner chaetae on basal and middle subsegments of dens modified as strong pointed spines. Pseudopores as small circular structures similar to sockets of chaetae, distributed at least on Th. II to Abd. IV, coxae, and manubrium.
Antenna 1.2–1.4 times as long as body. Antenna length ratio as I:II:III:IV= 1.0:1.4–1.5:13.9–15.2:0.8–1.0 in two paratypes. Both dorsal and ventral sides of Ant. I and Ant. II scaled, Ant. III dorso-basally with several scales. PAO rounded with four lobed vesicle, as large as eye. Eyes 6+6, relatively small than most edaphic species (Fig 2 A). Mouthparts typical for Tomocerinae. Labral chaetae formula as 4/5, 5, 4. Distal edge of labrum with four curved spine-like papillae. Mandibular head asymmetrical, the left one with 4 teeth and the right one with 5, left molar plate distally with a tapered tooth (Fig. 2 B). Basal teeth of maxillary lamella 5 longer than apical ones, without beard-like appendage (Fig. 2 C). Maxillary outer lobe with trifurcate palp, one basal chaeta and 4 sublobal hairs. Both dorsal and ventral sides of head scaled. Cephalic dorsal macrochaetotaxy: anterior area: 2, 2; interocular area: 2, 3, central uneven macrochaeta present; postocular area: 2+2; posterior area: 2+2. Posterior margin of head with 40–50 small chaetae (Fig. 2 D). Mentum with 5 chaetae, submentum with numerous chaetae.
Pattern of body chaetotaxy as in Fig. 2 E. Number of bothriotricha as 2, 1/ 0, 0, 1, 2, 0, 0 on Th. II–Abd. VI as typical in Tomocerinae. 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 four central macrochaetae arranged approximately in triangular pattern, postero-central chaeta near pseudopore; Abd.III with two anterior macrochaetae; Abd.IV with one antero-lateral macrochaeta; Abd.VI with numerous chaetae of moderate size. 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 from Th. II to Abd. VI (Fig. 2 E).
Trochantero-femoral organ with 1, 1 small slender chaetae (Fig. 2 F). Front, middle and hind tibiotarsus ventrally with 3–5, 4–5, 4–5 spine-like chaetae (Fig. 2 G). Each tibiotarsus with distal whorl of 11 chaetae, ventral six as ordinary chaetae, dorsal five modified: tenent hair clavate, about 0.45 times as long as inner edge of unguis; one pair of accessory chaetae small, slightly longer than pretarsal chaetae; one pair of guard chaetae thinner and shorter than tenent hair. 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. 3 A).
Ventral tube with scales on both anterior and posterior faces, lateral flaps unscaled, anterior face with about 30 chaetae on each side, posterior face with about 150 chaetae, each lateral flap with about 90 chaetae. Rami of tenaculum with 4+4 teeth, anterior face unscaled, with 2–3 small chaetae (Fig. 3 B). Furca length ratio as manubrium:dens:mucro=3.5–3.7:4.7–4.9:1.0. Manubrium ventrally scaled, without chaetae, laterally with large round scales, 1–2 small proximal chaetae and 10–15 distal strong chaetae; dorsal scales absent; each dorsal chaetal stripe with about 400 chaetae of different sizes, including 2+2 pointed prominent chaetae; pseudopores 15–20 on each side (Figs 1 B, 3C); external corner chaeta as large as moderate to large sized mesochaetae in chaetal stripe (Fig. 3 D). Dens basally with one pointed prominent dorsal chaeta, without large modified inner scale or strong outer chaetae. Dental spines formula as 3–5/4–6, I, 1–2, I; all spines with numerous moderate sized denticles (Fig. 3 E). Dens dorsally with ordinary chaetae and feather-like chaetae as in other Tomocerinae, ventrally covered by scales. Mucro elongated, bearing numerous smooth chaetae with elongated sockets (not shown in figure); both basal teeth with proximal lamellae, outer tooth with or without small toothlet; apical and subapical tooth subequal; structure of dorsal lamellae of Tomocerus type, two dorsal lamellae running from subapical tooth, outer lamella ending in inner basal tooth, inner lamella ending at base of mucro; outer lamella with 1–3 small intermediate teeth (Fig. 3 F). Genital plates normal for Tomocerinae, male with longitudinal genital orifice and numerals small chaetae on the plate, female with transversal genital orifice, exact chaetotaxy unclear.
Etymology. Specific name from Chinese word dong, meaning cave.
Remarks. Tomocerus dong sp. nov. resembles the Vietnamese species T. postantennalis and another new species T. deharvengi sp. nov. in the long antenna, the grey body colour, the morphology of claws, the type and arrangement of dental spines, and most of all, the presence of a well developed PAO, but the species can be readily distinguished from the latters by the sharp differences in the chaetotaxy on head and Th. II. Besides, compared to the other two species, the PAO of T. dong sp. nov. is of the same size but appears to be more complicated, probably implying a functional advantage. The labral formula is also different, T. postantennalis and T. deharvengi sp. nov. has six prelabral chaetae, while T. dong sp. nov. has four which is standard for Tomocerinae. Some individuals of T. dong sp. nov. lack the toothlet on the outer basal tooth of mucro, showing this classic generic character (Yosii 1955) can be variable within the same species.
description: Published as part of Yu, Daoyuan & Li, Youbang, 2016, New troglomorphic species of Tomocerus with well-developed postantennal organs (Collembola: Tomoceridae), pp. 361-372 in Zootaxa 4162 (2) on pages 362-365, DOI: 10.11646/zootaxa.4162.2.10, http://zenodo.org/record/272315