Monodiamesa bonalpicola Han and Tang, 2021

Han, Wu, Tang, Hongqu & Ni, Zhenyu, 2021, DNA barcodes and morphology reveal two new species of Monodiamesa Kieffer (Diptera: Chironomidae: Prodiamesinae) in Tibetan Plateau, Zootaxa 4990 (1), pp. 81-103 : 91-96

Monodiamesa bonalpicola Han and Tang , sp. n.

( Figs. 6–8 )

http://zoobank.org/ urn:lsid:zoobank.org:act:749541C3-C142-4431-B253-7A7EAB508ED1

Material examined. Holotype: 1 male, Pe /L, [Voucher No.: TB_53], CHINA: Tibet Autonomous Region, Nagqu Prefecture , Shenzha County, Gyaring Co , 30°58'42.3'' N, 88°28'42.4'' E, alt. 4649 m, 29.viii.2019, draft net, W. Han . Paratypes: 1 female, [Voucher No.: TB_54], as previous; 2 males [Voucher No.: Mon_01, Mon_02], 1 P/m, 1P/f, 3 Pe /2 Le , Tibet, Ngari Prefecture , Geji County, Yagi Township , Yare Township , Wamo Zangbo , 31°29'57.6'' N, 82°21'13.2'' E, alt. 4816 m, 01.ix.2020, draft net, W. Han; 8 Pe , CHINA: Qinghai Province, Madoi County , Zhaling Lake , 35°.0'29.1'' N, 97°.12'56'' E, 4330 m, 24.viii.2015, J. Liu; 2 Pe , Tibet, Chamdo Prefecture , Baxoi County , Rakwa Tso, 29° 29'58'' N, 96° 44' 1.2'' E, alt. 3920 m, 10.vii.2014, J. Liu .

Etymology. Bon-, refers to the native religious tradition of Tibet; - alpi, refers to ‘of high mountain’, - cola means ‘dweller, inhabitant’. The combination of ‘ bonalpicola’ means the species exists in the Tibetan high mountains and resembles the known European species M. alpicola ( Brundin, 1952)

Diagnostic characters.

Adult male. AR 1.40–1.51, clypeus with 10–14 setae; subapex of gonostylus nearly paralleled, even circumference. Length of apical spine of MVo subequal to the basal-sclerotized pedestal.

Adult female. AR 0.46–0.54, clypeus with 15–18 setae. Gonocoxapodeme straight, S VIII with reticulations, with many long setae (50–80 μm), arising from the large pits (diameter 20–30 μm). Gonocoxite IX well developed, relative slender, greatly free from the S IX. T IX with 10–15 setae on each round protrusion.

Pupa. Prealar tubercle well-developed and strongly sclerotized, no distinct wrinkles above the red-brown surface. Male genital sac clearly extends beyond the apex of anal lobe.

Larva. Median mentum teeth prominent, brown or pale brown, similar to lateral teeth; insertion of two genal setae under ventromental plate or very proximate to it.

Male (n =3, Fig. 6 ).

Total length, 5.85–6.30, 6.15 mm. Wing length, 2.70–3.10, 2.93 mm, wing width, 0.80–1.00, 0.88 mm.

Coloration. Mature form generally brown to dark brown, antenna with dark scape and brown flagellum. Thorax general grey brown with discernible dark vittae, scutellum and postnotum dark brown, halter yellowish brown. In some premature and teneral forms, the pleurae and scutellum bright yellow. Legs generally yellow. Wing bright glassy, crossveins slightly darker than other veins. Abdomen tergite general dark brown, sternite somewhat pale yellow, with some π-shaped brown ornaments in anterior ¾ of S VI–VIII and longitudinally median brown patch in S I–V.

Head. Eyes bare, extending parallel-sided ending in truncated terminals, separated by 5 x their terminal width. Flagellomere 1–12, 450–550, 500 μm; flagellomere 13, 700–760, 720 μm; AR 1.38–1.56, 1.45. Palpomere 1–5 lengths (in μm): 35–50, 40; 60–65, 63; 150–200, 175; 125–150, 141; 200–225, 213; the fourth palp shorter than the adjacent two segments, palp4/palp3, 0.75–0.86, 0.81. Temporals 7–10, 8. Clypeus with 10–14, 12 setae.

Thorax. Humeral pit distinct. Dorsocentrals 7–9, 8 in a single row, with 4–5 additional small light pits. Prealars 3–5, 4. Scutellum with 14–18, 16 setae, fairly two rows.

Wing. Anal lobe roundish, slightly projected. Squama with 20–25, 22 setae, in robust two rows. Crossvein MCu longer than oblique RM and its distance to RM and FCu; RM 80–100, 93 μm long; MCu 100–150,127 μm long; RM/MCu, 0.67–0.80, 0.75.

Legs. Fore tibia with one straight spur, 50 μm long; middle tibia with two subequal spurs, 40–50 μm long; hind tibia with two spurs, 50–60, 53 μm long and 75–100, 83 μm long. Hind tibial comb ( Fig. 6C ) with 8–12, 11 long spines, arranged in V-shape, shorten from lateral sides to middle, only presenting on the long spur side (inner side). Ta 1 and Ta 2 in the mid- and hind legs each with 2 pseudospurs subapically, 35–38, 36 μm long. LR 1, 0.75; LR 2, 0.44–0.48, 0.46; LR 3, 0.41–0.56, 0.51. BV 1, 2.65; BV 2, 2.97–3.11, 3.04; BV 3, 2.51–2.80, 2.64. BR 1, 3.4–3.6 (2); BR 2, 3.2–4.0, 3.67; BR 3, 4.0–4.44, 4.15.

Abdomen. Tergite setiferous with setae nearly covering all surface, subquadrate in general.

Hypopygium ( Figs. 6A, 6D, 6E ). Tergite IX with 10–14 setae at each posterolateral corner. Anal point short, broad triangular, each side with 4–5 lateral setae. Gonocoxite 275–300, 292 μm long. Superior volsella foot-shaped, dorsal surface with numerous inner-oriented macrotrichiae and 6–8 stronger setae in apical part, inner margin with 10–15 larger setae. Inferior volsella racket-like, with slender neck and inflated, quite rounded apical part, both surfaces covering numerous radially arranged macrotrichiae, slightly beyond the junction of gonocoxite/gonostylus. Median volsella bearing a cylindrical pedestal (ca. 8 μm wide x ca. 40 μm long) and a flexural digitus (ca. 40 μm long). Basal median lobe ( Fig. 6B ) reduced, slightly extending beyond the inner margin of gonocoxite, with 2–4 tubercle-based setae. Inner margin of gonocoxite with 5–6 ventromedial strong setae, 50–65 μm long. Gonostylus with slightly curved beak, 115–125, 120 μm long, 30–35 μm wide, about even thickness through the whole section; megaseta prominent, 16–20 μm high, with 2 subapical stiff setae. HR, 2.29–2.61, 2.43. HV, 4.68 (n = 1).

Female (n = 1 or 2, Fig. 7 ).

Total length 5.25–5.85 mm. Wing: length 3.6 mm, width 1.2 mm.

Coloration. Similar to male adults except the brown spermatheca.

Head. Eyes bare, dorsal extension short, with wedge-shaped terminal, separated by 4.0–4.5 x their terminal width. Antenna ( Fig. 7B ) with 6 flagellomere, flagellomere 1–5, 370–390 μm; flagellomere 6, 175–200 μm; AR 0.46–0.54. Palpomere lengths (in μm):40–45; 50–75; 120–130; 110–125; 200–250. Temporals 9–11. Clypeus with 15–18 setae.

Thorax. Antepronotals 8–10, 8. Dorsocentrals 10–14, 12, in a single row. Scutellars 16–20, 18, arranged in 3-4 rows. Prealars 3-5, 4.

Wing. Squama with 32–36 setae, arranged in two robust rows. Crossvein MCu longer than oblique RM and its distance to RM and FCu; RM 140 μm long; MCu 180 μm long; RM/MCu 0.78.

Legs. Fore tibia spur, 40 μm long; mid tibial spurs 50–54 μm long; hind tibial spurs, 56 μm and 87.5 μm long, respectively. Hind tibial comb with 10–12 long spines. Two pseudospurs at the subapical part of Ta 1 and Ta 2 of the mid- and hind legs, 35– 40 μm long. LR 1, 0.74; LR 2, 0.5; LR 3, 0.55. BV 1, 2.53; BV 2, 2.82; BV 3, 2.81. BR 2, 1.67.

Genitalia ( Figs. 7 A, C, D ). S VIII without distinct oval depression, with 13–16 setae (50–80 μm long) arising from the larger pale pits. Coxosternapodeme nearly straight, weakly sclerotized. Notum 150–200 μm long, slightly shorter than the rami, pale yellow in color. Dorsomesal lobe relative slender, expanded medially; ventrolateral lobe broad, with some anteriomedian-oriented long setae. Apodeme lobe rod-like, with weak microtrichia in the round apex. Three spermatheca oval, 50–70 μm in the long axis. Postgenital plate triangular shaped. Cercus ship-shaped, 160–200 μm long.

Pupa (n=4, Figs. 8 A–D )

Total length ( Fig. 8A ) 6.2–6.9, 6.5 mm. Coloration general yellow to light brown.

Cephalothorax. Cephalic tubercle and frontal seta absent. Thoracic suture with heavy granulations. Thorax horn broad ovate, 700–850, 825 μm long, thoracic horn ratio 2.80–3.15, 2.89. Accessory horn with four main tubularshaped basal branches. Antepronotal with 1 median and 2 lateral setae, 90–120 μm and 100–120 μm respectively. Precorneal with 2 well-developed and 1 reduced seta, 85–100 μm for the longer two setae and 40–50 μm for the reduced one. Prealar 1, 75–100 μm long, prealar tubercle well developed. Dorsocentrals grouped into 2 clusters, Dc 1–4 (in μm): 75–100; 40–60,51; 40–60, 50; 55–70, 63; the distance between Dc2 and Dc3 175–250, 207 μm.

Abdomen. T I bare. T II–V with extensive spinulations, subquadrate to triangular in outline. Spinulations on T VI hour-glass shaped, T VII T-shaped, T VIII reduced into two patches in the anterolateral corners. Spinose pedes spurii B ( Fig. 8C ) on segment II well developed, pedes spuria A on S IV–VII. Segments VII–VIII with 4 lateral taeniae, occasionally, one or two branched taeniae on segment VIII ( Fig. 8D ). Anal lobe 380–400, 395 μm high, 450–560, 520 μm wide, with 58–65, 60 fringe setae, single row in basal 2/3, and muti-serials in the distal 1/3. Two pairs of dorsal setae, the posterior pair hidden in the fringe terminals. Male genital ( Fig. 8B ) sac slightly extending the distal margin of anal lobe, 30–50, 46 μm.

Larva (exuviae, n = 2, Figs. 8E–G ).

Total length 6.5–7.5 mm. Head capsule 450–500 μm long, and 320–380 μm wide, cephalic index 1.32–1.45.

Head ( Fig. 8F ) yellow with dark brown apical mandible and mentum teeth. Antenna segment length (An1 to An4, in μm): 40–50; 20–23; 2–3; 4–5; AR 1.32–2.10. Length of basal segments about 2.1–3.0 times as long as width, a small sense pit just over the ring organ, basal setal mark absent. Blade 20–25 μm long, extending the apex of fourth segment, accessory blade 10–13 μm long, reaching the middle section of second segment. Lauterborn organ visible, inverse-fork shaped, style ca. 5 μm long, slightly longer than the Lauterborn organ. Premandible simple, 56–60 μm long, without brush. Mandible 120–130 μm long, apical teeth 25–30 μm long, clearly longer than the combined width of two inner teeth, the most basal inner teeth incompletely set off from the mola area. Seta subdentalis weak, 10–15 μm long, slightly extending the first true inner tooth; seta interna with 6 simple branches. Mentum ( Fig. 8G ) 100–120 μm wide in basal, subequal to the height. Median teeth with a weak notch, total width 30–35 μm, MR 0.28–0.35. Ventromental plate 20–25 μm wide in basal curved section, posterolateral margin roundish, with 6–8 beard underneath the plate, seldom extending beyond the outer margin. Two large genal setae very close to the posterolateral corner of ventromental plate. Postmentum 250–260 μm, distance between setae submenti 50–60 μm.

Body. Procercus ( Fig. 8E ) 40–50 μm high, 30–38 μm wide, with 7–8 anal setae, 650–800 μm long, two lateral setae of procerus, 120–160 μm and 50–55 μm long respectively. Two pairs of supraanal setae, the longer one 300–400 μm and the shorter one 150–160 μm long. Posterior parapods short, 170–200 μm long, with lateral setae 150–160 μm long.

Distribution. China Tibet.

Remarks. The male imago of M. bonalpicola sp. n. is very close to European M. alpicola and M. ekmani . The main differences are in the AR, and particularly in the hypopygium the ratio of the length of median volsella spine / the length of pedestal. For M. bonalpicola sp. n., the AR value is clearly lower than 2.0 and with a relatively longer median volsella pedestal. For the two known species, the AR value is around 2.0 and the length of median volsella spine is almost twice as long as the pedestal ( Table 2 ). The female and immature stages can be determined referring to the diagnostic characters, but it may be hard to separate them from its worldwide allies solely by these features.

Figures

FIGURE 6. Monodiamesa bonalpicola sp. n., male. Photos: (A) hypopygium; (B) basal median lobe; (C) hind tibial comb. Illustration: (D) hypopygium, dorsal view; (E) hypopygium, ventral view. Scale bar: A–E, 50 μm.

FIGURE 7. Monodiamesa bonalpicola sp. n., female. Photos: (A) hypopygium, ventral view. Illustration. (B) antenna; (C) S VIII; (D) hypopygium, ventral view. Scale bar: A, 50μm; B–E, 100 μm.

FIGURE 8. Monodiamesa bonalpicola sp. n., immatures. Photos: (A–B) pharate, P/M, lateral view, dorsal view; (C) pupa, pedes spurii B; (D) pupa, segment VIII; (E) larva, procercus. (F) larva, head capsule, ventral view. Illustration: (G) larva, mentum. Scale bar: A–B, 50 μm; C–D, 20μm; E–G, 50 μm.