Monodontocerus trigrandis Yu, Deharveng & Zhang, 2014, sp. nov.
Creators: name: Yu, Daoyuan
name: Deharveng, Louis
name: Zhang, Feng
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Entognatha
Collembola
Tomoceridae
Monodontocerus
Monodontocerus trigrandis

description: Monodontocerus trigrandis sp. nov.
Figs 5, 41 –53, 56, 59, Table 2
Type material. Holotype female and two paratype females on slides, one paratype in alcohol, collected in a small cave, Changshali Village, Sanhe Township, Xianghualing Town, Lingwu County, Hunan Province, China, 19.vi.2009, by Mingyi Tian and Zhihong Xue. Holotype, one paratype on slide and one paratype in alcohol in NJAU, one paratype on slide in MNHN.
Description. Body length 3.3–4.0 mm. Color pale, eye patches rather small, only ommatidia pigmented (Fig. 5).
Postantennal organ absent. Ommatidia 6+6, small. All observed antennae with Ant. IV fused to Ant. III. Antennae about 0.8 times length of body, length ratio as I: II: III+IV =1.0:2.6:18.2. Ant. I, Ant. II and base of Ant. III dorsally scaled; Ant. I and Ant. II with more s-chaetae on ventral side than on dorsal side; Ant. III+IV annulated, each subsegment near the middle of Ant. III with a whorl of about 30 chaetae. Types of chaetae similar to those of M. absens sp. nov. but without type c, s-chaetae uniformly distributed on this segment. Ant. III organ and normal Ant. IV not seen.
Labral formula 4/5, 5, 4, four distal papillae curved and blunt (Fig. 41). Mandible and maxilla typical for Tomocerinae; left mandible with 4 teeth, right mandible with 5 teeth, left molar plate with a distal tapering tooth (Fig. 42). Maxilla with 3 teeth and 6 lamellae, lamella 5 with long basal teeth, no beard observed (Fig. 43).
Maxillary outer lobe with a trifurcate palp, one basal chaeta and four sublobal hairs. Labial palp and labial chaetae not clearly observed.
Head dorsally scaled, macrochaetotaxy: antreior: 2, 2; interocular: 2, 3 (including one median chaeta); postocular: 2+2; posterior: 2. Chaetae on posterior margin not clearly seen (Fig. 56). Head ventrally scaled, with numerous smooth chaetae of different sizes.
TFO with 1, 1 slender smooth chaetae, smaller trochanteral chaetae also present. Femora with several long outstanding chaetae on inner side. Tibiotarsi distally with 0, 0, 2 relatively weak spine-like inner chaetae with pointed apices (Fig. 44), distal whorl with 11 chaetae, five dorsal chaetae smooth and pointed, tenent hair and two adjacent chaetae subequal, 1+1 outer chaetae longer and thicker (Figs 45, 46). Unguis slender in lateral view and stout in dorsal view (Figs 47, 48), outer edge 0.32, 0.29, 0.21 length of outer edge of fore, middle, and hind tibiotarsus, respectively, (Fig. 44), basally with internal ridging; lateral teeth relatively weak, with pointed apex; inner teeth two, distal tooth at about the middle of inner edge of unguis. Unguiculus 0.67–0.8 times length of inner edge of unguis, slender, with 1–3 inner teeth. Pretarsus with 1+1 microchaetae (Fig. 48).
Both faces of ventral tube scaled, each side of anterior face with about 40–50 chaetae, posterior side with about 120 chaetae; lateral flap unscaled, each side with about 50 chaetae. Rami of tenaculum with 4+4 teeth, corpus unscaled, with one anterior chaeta about as long as rami (Fig. 49). Chaetae on ventral tube and tenaculum smooth and pointed.
Furca about half as long as body, ratio manubrium: dens: mucro as 4.4: 5.8–5.9: 1.0. Manubrium ventrally scaled, lateral row with about 10 chaetae, distal chaetae strong and serrated. Each side of manubrium with a dorsal stripe of about 200 smooth chaetae of various sizes mixed with numerous scales; external pseudopores 17–20 on each side (Fig. 50), single externo-distal chaeta as long as mesochaetae in the chaetal stripe (Fig. 51). Manubrium about twice as long as wide.
Dens with three subsegments, basal: medial: distal = 1.0: 1.6–1.7: 3.2–3.5. Most dental spines lost in alcohol, the formula as 3, I/1–2, I, 1–2, I, 3–4, I in a single row judged from the sockets. Only one small spine and one large spine observed, both with a strong trunk and a few denticles, the larger spine about 0.08 times length of dens (Fig. 52). Types of dental chaetae as in M. absens sp. nov. Ventral side of dens covered by oval scales, without chaetae.
Mucro elongate and densely setaceous, with two dorsal lamellae; the single basal tooth with one proximal lamella; two intermediate teeth subequal; apical tooth stronger than subapical tooth (Fig. 53).
Tergal macrochaetae and large mesochaetae arranged as in Fig. 59. Number of macrochaetae in posterior row of Th. II–Abd. V constantly 3, 3, 3, 3, 4, 2, 4; on Th. II an additional macrochaeta internal to the posterior chaeta of the three central macrochaetae; on Abd. III antero-lateral macrochaeta smaller than the antero-inner chaeta; two anterior macrochaetae subequal in size on Abd. IV; on Abd. V macrochaeta p3 larger than the others and located more anteriorly; on Abd. VI seven macrochaetae present on dorsal flap. Pattern of bothriotricha as 2, 1/ 0, 0, 1, 2, 0, 0 from Th. II to Abd. VI. Pattern of mesochaetae and microchaetae not studied. Observed s-chaetae as follows: one s-microchaeta between two bothriotricha on Th. II, one s-microchaeta posterior to antero-lateral macrochaeta on Abd. III, several long s-chaetae near middle line on Abd. IV, one anterior normal s-chaeta on Abd. V.
Pseudopores near the middle of terga, pattern as 1, 1/1, 1, 1, 1, 0, 0 (Fig. 59). On Th. II pseudopore close to the externo-posterior chaeta of the three central macrochaetae; on Th. III–Abd. III pseudopores more near middle line; on Abd. I and Abd. II their location more posterior than on other terga.
Etymology. Named after the three large spines on the medial of dens.
Remarks. Monodontocerus trigrandis sp. nov. bears a third large spine on the medial part of dens, which is so far exclusive to this species among Monodontocerus species; however, this third large spine is smaller than the two distal spines. Other discriminating characters are the number of teeth on the unguis and mucro as listed in Table 2.
description: Published as part of Yu, Daoyuan, Deharveng, Louis & Zhang, Feng, 2014, New species of Monodontocerus (Collembola: Tomoceridae) from southern China with diagnostic notes on the genus and introduction of new taxonomic characters, pp. 557-575 in Zootaxa 3768 (5) on pages 568-572, DOI: 10.11646/zootaxa.3768.5.3, http://zenodo.org/record/228011