Nothybus sumatranus Enderlein

Lonsdale, O. & Marshall, S. A., 2016, Revision of the family Nothybidae (Diptera: Schizophora), Zootaxa 4098 (1), pp. 1-42 : 28-31

Nothybus sumatranus Enderlein

Figures 8–10, 55–63, 77, 78, 114–120

Nothybus sumatranus Enderlein 1922: 176 . Aczél 1955: 10 [family revision, key]; Steyskal 1977: 31 [Oriental catalogue]; Papp et al. 2006: 176 [ Thailand].

Description. Sumatra and Pahang morphotype, including type female and 2 non-type males (also see “Variation” below). ( Figs 55–57 )

Head: Mostly reddish brown with yellowish-orange areas; distal 2/3 of first flagellomere black; frons with anterolateral velvety patches confluent with anterior margin and dark parafacial; ocellar tubercle black; ventral half of face silvery tomentose with glossy medial tubercle dark brown in female and dark yellow in males; midpoint of face sometimes with horizontal brown line evident above silvery region; back of head with transverse band of faint whitish pruinosity above one pair of brown lateral spots.

Thorax: Yellowish-orange in base colour with dorsum of thorax darker. Scutum with medial brown stripe reaching anterior margin; stripe bounded by medial 6 rows of setulae anteriorly, and becoming wider postsuturally to nearly reach posterior supra-alar; stripe sometimes confluent with one pair of darker, narrow postsutural stripes originating at dorsocentral seta; one male with darker line along dorsocentral row; AMSA Pahang specimens with lateral margins of stripe expanded to fuse with lateral brown mottling, or with pigment slightly paler overall on thorax and with medial scutal stripe ending shortly before anterior margin (similar to Selangor specimens). Presutural scutum with brown mottling laterally, especially posterolaterally. Dorsal half of postpronotum brown with posterior region iridescent. Notopleuron brown (pigment sometimes slightly irregular) and with posterolateral iridescence, adjoining yellow ovate region on scutum usually bordered with similar irregular brown pigment; tubercle yellow, at least centrally. Scutellum dark brown with margin paler (more so towards venter), apex between and around apical setae orange; subscutellum brown. Metanotum with slight brownish tint, katatergite brown posteriorly or mostly yellow. Proepisternum dirty orange to brown laterally; anterior lobe with distal margin dark brown. Anepisternum brownish and iridescent posterodorsally. Posterodorsal corner of katepisternum and posterior region of anepisternum whitish-yellow.

Wing: Wing length 4.8–7.0mm. Similar overall to N. triguttatus but with pigment paler. Apex with infuscated area enclosing three clear iridescent spots, with second spot in cell r4+5 displaced apically. Transverse brown stripe narrow (more so to CuA1), barely extending into female cell r1 ( Fig. 77 ) and filling most of apex of male cell r1 (as in Fig. 78 ). Wing with faint, ill-defined brown spots apically on R4+5 and M1 (leaving at most a thin clear border along margin of veins). Subapical cloud on CuA1 small and indistinct. Vein r-m with narrow medial infuscation.

Legs: Coxae and femora light yellow, apices of femora dark brown (with pigment slightly extended along inner surface of fore femur); tibiae and tarsi dark brown except for fore basitarsomere, which is white with base narrowly orange to blackish ventrally (sometimes only setae darkened).

Abdomen: Tergites 2–4 dark brown except for anterolateral corner of tergite 2; male tergite 4 with broad orange-tinted region sublaterally. Tergite 5 black and velvety. Tergite 6 brown to brownish, darker laterally and posterolaterally. Some Pahang males with tergite 4 apparently entirely dark brown (possibly due to poor preservation).

Male terminalia: ( Figs 114–120 ) Tergite 6 band-like with several setae along posterolateral margin. Sternite 6 longer than wide, subtriangular with rounded anterior margin, setose on distal half with several longer marginal setae. Sternite 7 not evident in dissected material. Sternite 8 large and dome-like with several posterolateral setae marginally. Epandrium setose, fused to posterior half of surstylus. Surstylus approximately as high as epandrium, angled anteriorly but with slight posterior curve, minute setulae mostly clustered on distal half and inner-distal margin beside cluster of tubercle-like setae, inner surface confluent with subepandrial sclerite. Cercus flat, fingerlike. Hypandrium broadly fused to phallapodeme, setose medially and on narrow, prominent process with one longer apical seta; anteromedial margin broadly rounded, ventral lobe with ventromedial swelling with numerous setae anteriorly. Pregonite with slightly widened base adjoining hypandrium, outer surface minutely spinulose and textured, and with clear, gradually tapered apex; with one long anteroventral seta and several minute ventrolateral setae. Basiphallus triangular, sclerotized laterally, terminating in narrow, clear, sac-like process. Distiphallus long and unusually broad with one pair of thick ribbon-like bands divided on distal 1/3 into two pairs of narrower bands (apically fused into W-shaped structure with medial process elongate and bent).

Variation—Selangor: (Figs 58–60) Scutum with medial stripe not reaching anterior margin, with stripe either atrophied or broken subapically, leaving a floating spot anteriorly; stripe usually at least partially confluent with one pair of darker, narrow postsutural stripes originating at dorsocentral seta; notal pigmentation difficult to discern in BMNH specimens due to state of preservation. Metanotum yellowish-orange with brown mottling. Anepisternum with brownish mottling, especially anteriorly. Wing pigment strong, as in Fig. 78 . Tergite 4 with orange sublateral spots sometimes atrophied (mostly black); female tergite 6 brown along anterior, lateral and posterolateral margins.

Variation— Vietnam: Velvety anterolateral patch on frons sometimes narrowly separated from anterior margin; ocellar spot often extending anteriorly as narrow stripe that is longer in females; parafacial sometimes only brownish medially, along eye margin, or entirely yellow. Some Vietnamese specimens with scutal pattern as for Sumatra specimens (notal stripe wider, unbroken and reaching anterior margin), but some with presutural section of medial stripe fading before margin, or stripe faded anteriorly and near transverse suture to leave darker floating presutural spot (as in Selangor material); medial stripe slightly to strongly fused to posterolateral stripe that is itself faded to darkly pigmented; anepisternum with more extensive brownish mottling, especially anteriorly (similar to Selangor material), sometimes covering entire sclerite. Scutellum sometimes more extensively black along outer margins. Tergite 3 and sometimes also 2 sometimes orange sublaterally; paired orange regions on tergite 4 large, sometimes confluent, sometimes enveloping sclerite excluding posterior margin. Wing pigment strong, as in Fig. 78 . One female with tergite 6 brown and transverse stripe on wing broader anteriorly, expanding to surround apex of R2+3.

Variation— Thai males: (Figs 61–63) Velvety anterolateral patch on frons sometimes narrowly separated from anterior margin of frons; facial tubercle light brown or with slightly brownish tint; sometimes light brown to dark yellow. Frons with one pair of small white pruinescent patches anterior to posterior fronto-orbital. Thoracic and wing pattern sometimes as described for Selangor specimens, but sometimes paler or with medial scutal stripe strongly narrowed to midpoint with presutural section absent, and with brownish apical spots on R4+5 and M1 darker. Subscutellum and lateral surface of scutellum paler; scutellum sometimes with dorsal margin yellowishorange and venter of subscutellum yellow. Anepisternum with light whitish-grey pruinosity and with brownish mottling dorsally and anteromedially. Only dorsal margin of proepisternum brownish. Base of fore basitarsomere very narrowly brown. Abdomen with orange spots on tergite 4 larger, sometimes partially confluent, at least anteriorly, or widely confluent with only tergite margins brown (as in most Thai females). Terminalia of dissected Thai male as above except apex of distiphallus more slender with margins slightly converging, not parallel.

Variation— Thai females: As for Thai males except as follows. Face with very faint brown medial transverse line and glossy ventral tubercle brown to dark brown. Notal pattern sometimes faded, being reduced to smaller stripes and spots, including one large spot on postpronotum and adjacent spot on scutum; remnant of medial stripe often strong presuturally. Anepisternum with markings restricted to posterodorsal margin and one pale vertical anteromedial stripe. Fore basitarsomere with brown basal spot reduced to small vestige ventrally. Tergite 4 with dark pigment reduced, sometimes with only margins dark brown. Tergite 6 with lateral margin and anteromedial spot brown.

Distribution. Indonesia (Sumatra), Malaysia (Pahang, Sarawak, Selangor), Thailand, Vietnam.

Syntype. INDONESIA. Sumatra: N.O. Sumatra, Deli, Dr. Martin S.G. (1♀, ZMHU).

Additional material examined. INDONESIA. Sumatra: Sibolangit, forest, 3.vi.1985, J.W. Ismay, BM 1986-283 (2♂, BMNH), 12.xi.1983 (1♂, BMNH), (1♂, BMNH). MALAYSIA. Malaya, Pahang: Gua Che Yatim to Terenggan, 17.xii.1958, L.W. Quate (2♂, BPBM), Pahang: W. Malaysia, Old Bentong Pass nr Gombak, 16.iv.1985, D.K. McAlpine (1♂, AMSA), Sarawak: 4th Div, R.G.S. Mulu Expedition, BM 1977-543, forest path to camp 1, 19– 22.ix.1977, D. Hollis (2♀, BMNH), Selangor: Malaya, Gombak Field Stn., 14.xi.1977, B. Bendell (1♂, CNC), Malaya, Selangor, F.M.S., Gombak Valley, 26.xii.1930 (1♂, BMNH), Selangor, Ulu Gombak, 800ft, J.W. Ismay, BM 1986-283, 10.xi.1983 (1♂, BMNH), 12.xi.1983 (1♂ 1♀, BMNH), Selangor: Hulu, Langat, vi–vii.1988, C.S. Doi, bamboo thicket, CIE A19844 (1♀, BMNH), Sarawak: Mt. Kalujong, 1,800ft, 4.xi.1932, Oxford Univ. Exp., B.M Hobby & A.W. Moore, B.M.1933-254, primitive forest, undergrowth (1♀, BMNH), Selangor, Old Bentong Pass nr Genting turnoff, 11.iv.1985, D.K. McAlpine (1♀, AMSA), Genting Highlands, Road Junction, 15.vi.1973, D.K. McAlpine (1♂ 1♀, AMSA), Bentong Rd., 30km ex Kuala Lumpur, Gombak, K. Khoe, 1.xii.1987 (1♀, AMSA), 30.xii.1987 (1♂ 1♀, AMSA), Genting Highlands, Bentong Pass, D.K. McAlpine, 10.iv.1985 (1♀ 1?, AMSA), 12.iv.1985 (2♂, AMSA). THAILAND. “Peninsular Siam ”, Nakon Sri Tamarat, Khao duang, 2000 ft, 21.iii.1922, H.M. Pendlebury (1♀, BMNH), S Khao Lak Nat. Par., Tone Chong Fah Fall, 100km N Phuket, 20.x.1993, F. Kaplan & A. Freidberg (2♂ 1♀, TAU), S Khao Sok Nat. Per., Rt. 401, 22.x.1993, F. Kaplan & A. Freidberg (2♀, TAU), Banna, Chawang, nr Nabon, 70m, 6.ix.1958, J.L. Gressitt (1♂, CNC), Khorat Prov.: Sakaerat, 300km NE of Bangkok, 1.iii.1968, dry diplocot forest, D.E. Hardy (2♀, BPBM), Doi Suthep, 1278m, 29.iii–4.v.1958, water margin, T.C. Maa (1♀, BPBM; 1♀, CNC), Chantiburi Prov.: Kwad Soi Dao Wildlife Sanctuary, breeding centre, 9.viii.1987, R. deKeyzer (1♂ 1♀, AMSA), Chiang Rai Prov.: Pong Pah, 15.vii. 2013, 450m, 20.3812˚N, 99.8670˚E, M. Hauser (1♂, CSCA). VIETNAM. 22km S of Nha Trang, 20–26.xi.1960, C.M. Yoshimoto (2♂ 1♀, BPBM), Ban Me Thuot, 500m, 16–18.v.1960, L.W. Quate (1♂ 3♀, BPBM), Dak Song, 76km SW of Ban Me Thuot, 870m, 19–21.v.1960, L.W. Quate (1♀, BPBM), Fyan, 900–1000m, 11.vii–9.viii.1961, N.R. Spencer (1♀, BPBM), Ninh Binh, Cuc Phuong National Park, 20°21′13ʺN, 105°35′14ʺE, 350–500m, 30.iv– 8.v.2013 S.A. Marshall & S.M. Paiero (4♂ 1♀, DEBU), 2.v.2013, Marshall & Paiero (2♀, DEBU; 1♂ 1♀, CPNP), Ninh Binh, Cuc Phuong National Park, 20°18′35ʺN, 105°37′06ʺE, 11.viii.2013 S.A. Marshall (1♂, DEBU), Ninh Binh Province: Cuc Phuong National Park, 20˚21′01ʺN, 105˚35′35ʺE, ex hand collected, 13–17.vi.2014, M. Hauser & N. vonEllenreider (2♀, CSCA), Guang Ninh, Cat Ba Island, 20˚47′36ʺN, 106˚59′55ʺE, 12.viii.2011, S.A. Marshall (1♂, DEBU), Bac Giang, An Lac, Khe Ro Forest, 21˚20′26ʺN, 106˚58′00ʺE, 75–150m, 16–18.v.2013, Marshall & Paiero (2♀, DEBU).

Comments. Nothybus sumatranus is relatively widespread in the Oriental Region, and the most morphologically variable of all Nothybus species. Specimens vary in width and length of the transverse brown band on the wing, strength of the scutal stripe, size (or absence) of the orange spots on tergite 4, and colour of the facial tubercle and female tergite 6, but there are no clear patterns of correlated characters supporting the division of N. sumatranus into additional taxa. Furthermore, the male terminalia of non-Sumatran specimens, except for one Thai male with the apex of the phallus slightly narrowed, are identical with the Sumatran male dissected.

Figures

FIGURES 55 – 57. Nothybus sumatranus Enderlein, female syntype, photos; 55: left lateral; 56: head, anterior; 57: head and thorax, dorsal. FIGURES 58 – 60: N. sumatranus, male, Selangor, photos; 58: left lateral; 59: head, anterior; 60: head and thorax, dorsal. FIGURES 61 – 63: N. sumatranus, male, Thailand, photos; 61: left lateral; 62: head, anterior; 63: head and thorax, dorsal. FIGURES 64 – 66: N. triguttatus Bezzi male, Selangor, photos; 64: head and thorax, dorsal; 65: left lateral; 66: head, anterior.

FIGURES 67 – 78. wings, photos; 67: Nothybus longicollis (Walker), with relevant veins listed; 68: N. biguttatus Wulp; 69: N. kempi (Brunetti), with relevant cells listed; 70: N. procerus spec. nov., holotype; 71: N. kuznetsovorum Galinskaya & Shatalkin; 72: N. cataractus spec. nov.; 73: N. lineifer Enderlein, syntype; 74: N. decorus Meijere [syn. nov. of N. lineifer], syntype; 75: N. lineifer, CNC specimen; 76: N. triguttatus Bezzi; 77: N. sumatranus Enderlein, syntype; 78: N. sumatranus, Thai specimen.

FIGURES 114 – 120. Nothybus sumatranus Enderlein, male abdomen; 114: external components, segment 6 to cercus, left lateral; 115: external components past sternite 8, posterior; 116: external components, segment 6 to cercus, ventral; 117: external components past sternite 8, anterior; 118: ejaculatory apodeme; 119: internal components, ventral; 120: same, left lateral.