Megarthrus flavolimbatus Cameron, 1924

Liu, Zhiping & Cuccodoro, Giulio, 2021, Megarthrus of China. Part 4. The M. hemipterus complex (Coleoptera, Staphylinidae, Proteininae), with description of a new species from Yunnan Province, ZooKeys 1056, pp. 17-34 : 17

Megarthrus flavolimbatus Cameron, 1924

Figs 4-6 , 11 , 14 , 17 , 41

Megarthrus flavolimbatus Cameron, 1924: 164; Cuccodoro 2003: 377 (detailed redescription, the first record for China); Cuccodoro 2011: 38 (photograph of dorsal habitus, Taiwanese records in China).

Diagnosis.

For detailed morphology see Cuccodoro (2003). Combined length of head, pronotum, and elytra 1.6-1.9 mm; maximal pronotal width = 0.9-1.1 mm. Body (Figs 4-6 ) predominantly chestnut brown, with pronotum slightly paler along lateral edges, frons slightly paler than vertex, and legs slightly paler than elytra. Anterior frontal margin slightly carinate, more convex at middle than laterally in dorsal view.

Male. Protibia fairly straight and evenly expanding from base to apex; adventral side shallowly depressed transversely. Mesotrochanter with about a dozen peg-like setae arranged in two rows. Mesofemur fairly straight and slightly swollen. Mesotibia subangulate, bearing peg-like setae arranged in one row. Metatrochanter and metafemur slightly swollen; posterior margin of metatrochanter evenly arcuate; inner margin of metafemur fairly straight in ventral view, forming sharp ridge on entire length. Metatibia swollen, at middle forming conspicuous tooth-like process projecting above flattened apical portion of metatibia; metatibial peg-like setae grouped as a dense field on apical third, discontinuously with 1 peg-like seta to at most 7 peg-like setae on distal side of tooth-like process; proximal side of tooth-like process convex, with at most 1 peg-like seta. Aedeagus (Figs 11 , 14 ) with ventral wall slightly narrowed at base and evenly narrowed to acutely angled apex in ventral view, and with ventral outline fairly straight to slightly recurved apex in lateral view.

Female. Gonocoxal plate with lateral portions of dorsobasal margin with oblique to middle portion truncate, markedly projecting anterad. Dorsal part of genitalia (Fig. 17 ) with evenly thick semi-circular sclerite.

Comparisons and diagnostic notes.

See above under M. dentipes .

Material examined.

(92 specimens): China: Fujian Prov.: N of Wutongyang, 26°03'N, 117°38'E, 12.v.2010, 1000-1700 m, leg. J. Tuma, 25 ♂ and 9 ♀ in MHNG, NHMW & ZMUC; Hunan Prov.: Shunhuangshan Forest Park, 26°24'N, 111°01'E, 22.v.2013, 700- 1200 m, leg. Jatua, 6 ♂ and 7 ♀ in MHNG & NHMW; Shaanxi Prov.: Qin Ling Shan, river valley 40 km S Xian, highway km 50, 33.55N, 108.49E, 1200 m, 31.viii.1995, leg. D. W. Wrase, river bank, 1 ♂ in cSch; Sichuan Prov.: Qingcheng Shan, NW Chengdu, 650-700 m, 30°53'57"N, 103°32'23"E, 3-4.vi.1997, leg. M. Schülke (17), 1 ♂ and 2 ♀ in cSch; Qingcheng Shan, 65 km NW Chengdu, 8 km W Taiping, 35.53N, 103.33E, 800-1000m, 18.v./ 3-4.vi.1997, leg. A. Pütz, 2 ♂ and 2 ♀ in cPüt & MHNG; Emei Shan, 29°33'04"N, 103°21'19"E, 25.vi.2011, 1729 m, leg. V. Grebennikov (sift 05) 2 ♂ and 1 ♀ in MHNG; Emei Shan, 29°36'06"N, 103°20'06"E, 27.vi-. 5.vii.2009, 1800-2400 m, leg. V. Grebennikov (siftings 11-17) 2 ♂ and 1 ♀ in MHNG; Ya’an Pref., Shimian Co. Xiaoxiang Ling, 11 km S Shimian, side-valley above Nanya Cun near Caluo, 1250 m, 7. VII.1999, leg. A. Pütz, 1 ♀ in cPüt; Yunnan Prov.: Baoshan Pref., Gaoligong Shan, E pass, 36 km SE Tengchong, 24°49'32"N, 98°46'06"E, 2200 m, 31.v.2007, leg. A. Pütz, [CH07-13] deciduous forest, litter, wood, fungi sifted, 2 ♂ in cPüt; Baoshan Pref., Gaoligong Shan, 36 km SE Tengchong, 24°51'22"N, 98°45'36"E, 2100-2200 m, 31.v.2007, leg. A. Pütz [CH07-14], deciduous forest, litter, wood, fungi, sifted, 1 ♂ in cPüt; Baoshan Pref., mountain range 14 km E Tengchong, 25°00'28"N, 98°38'07"E, 1850 m, 1.vi.2007, leg. A. Pütz [CH07-16] second, mixed forest, litter sifted, 1 ♂ in cPüt; Baoshan Pref., mountain range 25 km S Tengchong, 24°48'28"N, 98°32'03"E, 1900 m, 2.vi.2007, leg. A. Pütz [CH07-17], dev. primary deciduous forest, litter, fungi, sifted, 1 ♀ in cPüt; Ruili, 4.ii.1993, G. de Rougemont, 2 ♂ and 2 ♀ in MHNG & SCNU; Xishuangbanna, 22.i.1993, G. de Rougemont, 2 ♂ and 3 ♀ in MHNG; Kunming, 9.x.1985, G. de Rougemont, 1 ♀ in MHNG; Kunming, x.1986, G. de Rougemont, 1 ♂ in MHNG; Baoshan Pref., Gaoligong Shan, E pass, 36 km SE Tengchong, 2200 m, 24°49'32"N, 98°46'06"E, 4.vi.2007, leg. M. Schülke [CH07-13], deciduous forest, litter, wood, fungi, sifted, 4 ♂ and 1 ♀ in cSch; Xishan Mts, 24.57N 102.38E, 2300 m, 27.vi.1993, leg. V. Kubáñ, 1 ♂ in NHMB; NE Kunming, 25°08'40"N, 102°53'48"E, 2290 m, 11. VIII. 2014, leg. V. Assing [5] mixed forest, sifted, 1 ♂ in cAss; NE Kunming, Xiaobailong Forest Park, 24°55'43"N, 103°05'27"E, 2110 m, 10.viii.2014, leg. M. Schülke [CH14-03], secondary pine forest margin, litter, sifted, 3 ♀ in cSch; Dali Bai Aut. Pref., Wuliang Shan, 9km SW Weishan, 25°10'15.5"N, 100°14'21.8"E, 2480 m, 14.ix.2009, leg. M. Schülke [CH09-51], scrub with (oak, alder, pine) litter and mushrooms, sifted, 2 ♀ in cSch; Baoshan Pref. Mountain range 25 km S Tengchong, 24°48'28"N, 98°32'03"E, 1900 m, 2.vi.2007, leg. M. Schülke, [CH07-17], dev. primary deciduous forest, litter, fungi, sifted, 1 ♀ in cSch; Gaoligong Shan, Pass SW Baoshan, 4-8.vi.2006, leg. Jeniš, 1 ♀ in cAss.

Distribution and natural history.

Megarthrus flavolimbatus is the most widespread member of the genus in the Oriental Realm, with records ranging from North India (Himachal Pradesh and West Bengal) to Yunnan Province and Taiwan in China ( Cuccodoro 2003, 2011); here, we report it for the first time also from Fujian, Hunan, Shaanxi and Sichuan Provinces in China (Fig. 41 ). It was found at elevations ranging from 250 to 3375 m a. s. l. in Taiwan ( Cuccodoro 2011), and its altitudinal range appears quite wide also in mainland China (i.e., from 1000 to 1700 m a. s. l. in Fujian, from 7000 to 1200 m a. s. l. in Hunan, from 1850 to 2480 m a. s. l. in Yunnan, from 650 to 2400 m a. s. l. in Sichuan, and at 1200 m a. s. l. in Shaanxi). The species occurs in various types of forests (evergreen broadleaved, deciduous broadleaved, mixed coniferous and evergreen broadleaved, and coniferous forests) as well as in orchards, where it was collected mainly from sifted samples of moist decaying debris of vegetation (leaf litter, humus, rotting wood) with fungi, and occasionally even from chicken excrement ( Cuccodoro 2011).

Figures

Figure 41. Distribution map in China of Megarthrus dentipes Bernhauer, M. flavolimbatus Cameron, M. hemipterus (Illiger) and Megarthrus panda sp. nov. Scale bar: 300 km.

Figures 4 - 6. Megarthrus flavolimbatus Cameron: habitus, male: dorsal 4 ventral 5 and lateral 6 views. Scale bar: 0.5 mm.

Figures 10 - 18. Megarthrus dentipes Bernhauer (10, 13, 16) M. flavolimbatus Cameron (11, 14, 17) M. hemipterus (Illiger) (12, 15, 18) male: aedeagus in ventral (10 - 12) and lateral (13 - 15) views female: genital segments, dorsal part (16 - 18) in ventral view. Scale bars: 0.1 mm.