Amphichroum angustilobatum Shavrin & Smetana, 2018

Shavrin, Alexey V. & Smetana, Aleš, 2018, New species of the genus Amphichroum Kraatz, 1857 (Coleoptera: Staphylinidae: Omaliinae: Anthophagini) from China, Zootaxa 4508 (3), pp. 377-402 : 378-382

Amphichroum angustilobatum Shavrin & Smetana , sp.n.

( Figs. 1 , 5–7 , 11 , 41 )

Type material examined: Holotype ♂ [specimen dissected]: ‘ CHINA: N-Yunnan [C 2005-07 A] | Diqing Tibet. Aut. Pref., | Deqin Co., Meili Xue Shan , E-side, | 12 km SW Deqin, 2890 m, | 28°25.30'N, 98°48.47'E,’ <rectangular label, printed>,‘small creek valley, mixed forest | with bamboo, leaf litter, moss, | dead wood, sifted, 13. VI .2005, | leg. M. Schülke [C 2005-07 A]’ <rectangular label, printed>, ‘ HOLOTYPE | Amphichroum | angustilobatum sp.n. | Shavrin A. & Smetana A. des. 2018’ <red rectangular label, printed> ( CSC) .

Paratype ♀: ‘ CHINA: N-Yunnan Diqing Tibet. | Aut.Pr. Deqin Co. Meili Xue | Shan E-side 12km SW Deqin | 28°25.30'N 98°48.47'E 2890 m | 13. VI .2005 A. Smetana [C160]’<rectangular label, printed>, ‘ PARATYPE | Amphichroum | angustilobatum sp.n. | Shavrin A. & Smetana A. des. 2018’ <red rectangular label, printed> ( NSMT) .

Description. Measurements (n=2): HW: 0.57–0.60; HL: 0.32–0.34; AL(holotype): 1.13; OL: 0.17; PL: 0.57– 0.62; PW: 0.92; ESL: 1.12; EW: 1.14–1.31; AW: 1.12; MTbL(holotype): 0.62; MTrL(holotype): 0.54 (MTrL 1–4: 0.32; MTrL 5: 0.22); AedL(holotype): 0.62; TL: 2.85–3.10 (holotype).

Head, antennomeres 5–11 and disc of pronotum yellow-brown; mouthparts, antennomeres 1–4, lateral portions of pronotum, elytra and legs yellow; abdomen reddish-brown. Forebody with oily sheen, abdomen shiny; head with dense transverse microsculpture, with more or less rounded microsculpture on infraorbital ridges and neck; pronotum without microsculpture except for median third of disc with irregular and indistinct transverse microsculpture; scutellum with indistinct transverse microsculpture; abdominal tergites with very dense and distinct isodiametric microsculpture. Head without punctation except for posterior portion between grooves and infraorbital ridges with several smoothed large punctures; pronotum with dense, regular, small punctation, slightly deeper and larger on posterio-lateral portions; punctation of elytra dense, large and smoothed, distinctly denser, smaller and deeper on prescutellar area; abdominal tergites with irregular, indistinct and small punctures. Head with several very long setae on frontal portions, with two long yellow setae on median part of head between anterior parets of eyes and four pairs of long setae on posterior part of infraorbital ridge along occipital line; pronotum with dense, and very fine, regular yellow pubescence, and with two pairs of very long black setae near anterior margin and four pairs of similar setae on lateral margins; fine pubescence of elytra as that on pronotum, with additional five to six pairs of very long black setae on lateral portions; abdominal tergites with irregular setation and with long and erect black setae on paratergites and apical segments.

Head subtrapezoidal, 1.7 times as wide as long, flattened in middle and slightly convex on posterior portions of infraorbital ridges; grooves in front of ocelli narrow, deep and long, diagonally stretching toward antennal bases to level of anterior margins of eyes. Ocelli very large, located at level of posterior margins of eyes near occipital furrow, distance between ocelli slightly longer than distance between ocellus and posterior margin of eye. Eyes very large, convex. Apical segment of maxillary palp 1.2 times as long as preceding segment, gradually narrowed apicad from basal third. Antenna moderately long, reaching one-fourth of elytral length when reclined; length × width of antennomeres (holotype): 1: 0.13 × 0.05; 2: 0.11 × 0.05; 3: 0.11 × 0.04; 4: 0.07 × 0.05; 5–8: 0.10 × 0.05; 9–10: 0.08 × 0.06; 11: 0.15 × 0.06.

Pronotum 1.4–1.6 times as wide as long, 1.5–1.6 times as wide as head, widest at about middle, slightly more narrowed posteriad than anteriad; anterior angles rounded, indistinctly protruded apicad; posterior angles widely rounded; lateral portions flattened and slightly explanate, gradually widened posteriad.

Elytra slightly wider than long, distinctly widened apicad, reaching apical margin of abdominal tergite IV or V, slightly less than twice as long as pronotum, with widely rounded apical margins, truncated at suture.

Legs moderately long; metatibia about 1.1 times as long as metatarsus, with long strong thorns on inner and outer surface and long setae between them.

Abdomen slightly or distinctly narrower than elytra, with a pair of very large transverse tomentose spots in middle of tergite IV, with wide palisade fringe on apical margin of tergite VII.

Male ( Fig. 1 ). Protarsomeres 1–4 very wide. Medial margin of apical part of protibia with two parallel rows of five short peg setae; mesotibia strongly curved mediad, with dense row of fourteen very short and wide thorns beginning from medial side of bend and stretching to apex of mesotibia; lateral margin of tibiae without long strong thorns, except for those around apex. Abdominal tergite VIII and sternite VIII with straight apical margin. Aedeagus ( Fig. 5 ) with wide basal portion strongly narrowed apicad, median lobe narrow with elongated apical portion; parameres narrow, distinctly exceeding apex of median lobe, with two pairs of apical and preapical short setae; internal sac ( Fig. 6 ) long, with two pairs of wide thorns in apical and complicated sclerotized structures in basal portion. Aedeagus laterally as in Fig. 7 .

Female. Protarsomeres 1–4 moderately narrow. Medial margin of protibia without peg setae; mesotibia without modifications, slender, gradually slightly widened apicad, with long strong thorns along entire length of lateral margin. Abdominal tergite VIII and sternite VIII with small rounded apical margin.

Comparative notes. Based on the body size, coloration and general shape of the apical part of the aedeagus, A. angustilobatum sp.n. is most similar to A. pindarense ( India, Bhutan and Xizang) and A. schuelkei sp.n. (Yunnan), from which it differs by the wider basal part of the aedeagus and different structure of the internal sac. Additionally, from A. schuelkei sp.n. it differs by more distinct microsculpture of the head, longer antennomeres 4–10, and wider apical portions of the parameres.

Distribution. The new species is at present known only from the type locality in the Meili Xue Shan range in Yunnan, China ( Fig. 41 ).

Bionomics. Specimens were collected at elevation 2890 m. The holotype was taken by sifting leaf litter, moss and dead wood in small creek valley in mixed forest with bamboo (locality C 2005-07 A: Fig. 11 ); the paratype was taken by sifting various debris along the creek and in a spray zone of a small waterfall in mixed broadleaved forest with broadleaved shrubs in undergrowth (locality: C160).

Etymology. The specific epithet is a combination of Latin adjective angustus, - a, - um (narrow) and lobatus, -a, -um (lobed). It refers to narrow median lobe of the aedeagus.

Figures

FIGURE 11. Type locality of Amphichroum angustilobatum sp.n.in the Meili Xue Shan range in Yunnan (photograph: M. Schülke (locality C2005-07A)).

FIGURE 41. Distribution of Amphichroum in China: A. angustilobatum sp.n. (black star), A. assingi sp.n. (white square with wide black margin), A. longilobatum sp.n. (white circle), A. maculosum sp.n. (white star), A. miaoershanum Watanabe, 1999 (circle with wide white margin), A. propinquum sp.n. (black square), A. rotundatum (white square), A. schuelkei sp.n. (black rhomb), A. squamosum sp.n. (black circle), A.subaequale sp.n. (white rhomb), A. subelongatum sp.n. (black triangle), A. tibetanum sp.n. (white triangle).

FIGURES 1–4. Habitus of Amphichroum (males): 1–A. angustilobatum sp.n. (holotype), 2–A. assingi sp.n. (holotype), 3–A. longilobatum sp.n. (paratype), 4–A. maculosum sp.n. (holotype). Scale bar: 1.0 mm.

FIGURES 5–10. Aedeagus of Amphichroum angustilobatum sp.n.(5–7: holotype) and A. assingi sp.n. (8–10: paratype): 5, 8– parameral view (outline of internal sac shown as point line), 6, 9–internal sac, 7, 10–lateral view. Scale bar: 0.1 mm.