Megauchenia angustata ( Erichson, 1843 )

Dasgupta, J., Pal, T. K. & Hegde, V. D., 2015, Review of the Megauchenia Macleay of India (Coleoptera: Nitidulidae: Prometopinae), Zootaxa 4058 (4), pp. 551-560 : 557-558

Megauchenia angustata ( Erichson, 1843)

Ischaena angustata Ericshon 1843: 288 .

Ischaena angustata var. peninsularis Grouvelle 1890: 123 , 124.

Megauchenia angustata: Grouvelle 1913a: 136 ; Grouvelle 1913b: 100; Kirejtshuk 2005: 63; Jelínek & Audisio 2007: 473.

Diagnosis. Body ( Figs. 19–20 ) elongate-ovoid, dark brown to black, moderately shiny. Lateral margin of pronotum arcuate. Elytral sides subparallel with apices gently arcuate and margin uniformly round, intervals between elytral striae wider than the striae; dorsum coarsely punctate; elytra with sparse, short, golden, erect squamous setae.

Head transverse, about 1.3x as broad as long, frons feebly depressed; punctation on frons round, distinct, diameter about 3x as large as those of vertex, separated by about 0.5–1 diameter of punctures; punctures on vertex oval and shallow; setae on frons indistinct; eyes large and moderately projected, about 0.3x as long as head, outer margin rounded, coarsely facetted, ocular border of head slightly carinate. Antenna about 1.4x as long as head; antennal club about as long as broad, about 0.3x as long as antenna.

Prothorax transverse (l.0: 1.3), anterior margin slightly emarginate; sides arcuate, posterior margin bisinuate with a distinct emargination at middle, anterior and posterior angles somewhat pointed. Pronotum rather convex, surface distinctly punctate, punctures round, dense, distinct, separated on top of pronotal disc by 0.75–1 diameter, setae on disc indistinct.

Scutellar shield transverse, about 1.6x as broad as long, triangular and somewhat rounded apically; punctures smaller than those on pronotum, setae indistinct.

Elytra together about 1.4x as long as broad, anterior margin closely fitting with hind margin of prothorax, humeral angles projected anteriorly, sides subparallel, slightly explanate, apices separately rounded; punctures almost as large as those on pronotum, arranged in ten longitudinal rows, separated by 1–2 diameters; setae short, erect, posteriorly directed and arranged along striae.

Abdominal tergites almost completely concealed under the elytra; punctures on second and fifth abdominal ventrites slightly larger than those on first, punctures on third and fourth ventrites are elongated and larger than all other ventrites; setae moderately long, uniformly arranged, closely appressed to the surface of the abdomen, posteriorly directed.

Ventral side uniformly chestnut-brown; gular region of head with posteriorly converging antennal grooves. Metaventrite punctate, mesocoxal lines reaching almost up to two-thirds of the length of the metaventralmetanepisternal suture from base, thereby creating a distinct axillary space.

Aedeagus ( Figs. 14–15 , 23–24 ): Parameres slightly dilated medially, foot-shaped with setose apical margin, apex broader than width of parameres. Median lobe elongate-ovoid with an elongated flap extended ventrally from either side, apex slightly notched.

Measurements (in mm): Total length 4.69–4.91, width of head across eyes 0.85–0.89, length of antenna 0.92– 1.14, length and width of prothorax 1.24–1.42 and 1.84–1.98, length and width of elytra together 2.85–2.87 and 1.93–2.01.

Material examined. 26 ex. INDIA: Meghalaya, Garo Hills, Songsak Reserve Forest, 1 ex., 21.ii.1974, T. Sengupta & party, ex. under bark of Shorea robusta Roth ; Meghalaya, W. Garo Hill Dist., Barangapara, 1 ex., 23.iv.1991, B. N. Das & party; Meghalaya, Rongjing Giri Reserve Forest, Garo Hills, 2 ex., 18.iv.1973, S. Biswas, ex. under bark (Det. Hisamatsu,1973, Reg. No. 5416-5417/H4A); Arunachal Pradesh, Abor expedition, below Dosing, 427m,1 ex., 29.i.1912, S. Kemp, Reg. No. 2504/19; Arunachal Pradesh, Abor Expedition, Kobo, 122m, 3 ex., 02-12.xii.1911, S. Kemp, ex. under bark in rotting wood, Reg. No. 2497/19, 2430/19, 2496/19; Arunachal Pradesh, Namdapha WLS, Miao, 1 ex., 01.xii.1982, S. Biswas; Arunachal Pradesh, Namdapha WLS, Gibbon Land, 1 ex., 03.v.1981, S. Biswas; Arunachal Pradesh, L. Subansiri Dist., 4 km-o-Kimin, 1 ex., 21.ix.1988, T. K. Pal & party, ex. under bark; Arunachal Pradesh, L. Dibang Valley Dist., Parbuk, 1 ex., 11.iv.2009, T. K. Pal & party, ex. under bark; Arunachal Pradesh, W. Siang Dist., Likabali, 1 ex., 12.iii.1989, T. K. Pal, ex. under bark; Arunachal Pradesh, L. Dibang Valley Dist., Sally Lake, Roing, 1 ex., 04.iv.2009, T. K. Pal & party, ex. under bark; Arunachal Pradesh, Dibang Valley Dist., 3 km-O-Roing, 1 ex., 08.ix.1991, T. K. Pal, ex. under bark; Arunachal Pradesh, L. Subansiri Dist., Hawa Camp, 15 km-O-Kimin, 1 ex., 22.ix.1988, T. K. Pal & party, ex. under bark; Nagaland, Dimapur Dist., Rangapahar WLS, 130m, 1 ex., 31.x.1998, T. K. Pal & party, ex., under bark of tree stump; Sikkim, 1 ex., iv-v.1983, B. N. Das; Sikkim, Tista Bridge, 152m, Tista Valley, 1 ex., 15. vi. 1934, S. L. Hora, ex. at light; Andaman & Nicobar, Great Nicobar Island, South Bay, 45 km-NSRD, 1 ex., S.S. Saha, ex. decaying log; Andaman & Nicobar Islands, Andaman, 2 ex. (Det. Grouvelle, Reg. No. 8695/18 and 8693/18); West Bengal, Dhupgiri, 2 ex., 15.iv.1971, T. Sengupta, ex. under bark; INDONESIA: N. O. Sumatra, Tandjong, Morawa, Serdana, B. Hagen, 1 ex. (Reg. No. 1352/13); MYANMAR: Thingannytinaung to Sukli, Dawna hills, 244–640m, 1 ex., 08–27.xi.1911, F. H. Gravely, ex. under bark of a fallen tree trunk (Reg. No. 557/19).

Distribution. INDIA: Meghalaya, Sikkim, Nagaland, West Bengal, Andaman & Nicobar Islands (all new records), Arunachal Pradesh; NEPAL; BHUTAN; MYANMAR; THAILAND; LAOS, CAMBODIA; INDONESIA: Mentawai, Sumatra, Borneo; PHILIPPINES; MALAYSIA; VIETNAM; RYUKUS; JAPAN; TAIWAN.

Figures

FIGURES 19 – 30. 19, 21, 29 (dorsal habitus): 19, Megauchenia angustata (Erichson, 1843); 21, M. quadricollis (Reitter, 1883); 29, M. indica (Grouvelle, 1908); 20, 22, 30 (ventral habitus): 20, M. angustata; 22, M. quadricollis; 30, M. indica. 23 – 28: male genitalia: 23, tegmen and median lobe of M. angustata, microphotograph; 24, median lobe of M. angustata after separating from tegmen, microphotograph; 25, tegmen and median lobe of M. quadricollis, microphotograph; 26, median lobe of M. quadricollis after separating from tegmen, microphotograph; 27, tegmen of M. quadricollis, line drawing; 28, median lobe of M. quadricollis, line drawing.

FIGURES 8 – 18. Megauchenia angustata (Erichson, 1843), line drawings: 8, mandible, dorsal view; 9, maxilla, ventral view; 10, labium, ventral view; 11, labrum, dorsal view; 12, mesoscutellum, dorsal view; 13, anal sclerite (tergite VIII); 14, male genitalia: tegmen, ventral view; 15, male genitalia: median lobe, ventral view; 16, spiculum gastrale; 17, ovipositor; 18, metendosternite.