Amphichroum propinquum 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 : 387-390

Amphichroum propinquum Shavrin & Smetana , sp.n.

( Figs. 16 , 20–21 , 41 )

Type material examined: Holotype ♂: ‘ China: W-Sichuan, Daxue Shan | Gongga Shan, Moxi, 1700m | 11. - 13.07.1999 | 29° 39' N, 102° 06' E | leg. [V]. Siniaev & A. Plutenko’ <rectangular label, printed>, ‘ Amphichroum [handwritten] | sp. [handwritten] | det. Zanetti 2001’ <rectangular label, printed>, ‘ Sammlung M. Schülke | Berlin | Ankauf Plutenkov 1999’ <green rectangular label, printed >, ‘ HOLOTYPE | Amphichroum | propinquum sp.n. | Shavrin A. & Smetana A. des. 2018’ <red rectangular label, printed>( CSC) .

Paratype ♀: same data as the holotype, with red rectangular label ‘ PARATYPE | Amphichroum | propinquum sp.n. | Shavrin A. & Smetana A. des. 2018’ ( CSC) .

Description. Measurements (n=2): HW: 0.60–0.64; HL: 0.37; AL(holotype): 1.24; OL: 0.17; PL: 0.62–0.66; PW: 0.95–1.07; ESL: 1.12–1.21; EW: 1.25–1.45; AW: 1.15–1.46; MTbL(holotype): 0.65; MTrL(holotype): 0.55 (MTrL 1–4: 0.32; MTrL 5: 0.22); AedL: 0.85; TL: 3.00 (holotype) –3.15.

Body yellow-brown to reddish-brown; antennomeres 4–11 brown; mouthparts, antennomeres 1–3, legs, paratergites and apical segments of abdomen yellow (paratype with yellow abdomen except for median parts of tergites 4–6).Head with irregular small and deep punctures, denser on middle portion and on infraorbital ridges and deeper between grooves; pronotum with dense punctures, smaller than those in middle part of head, with narrow impunctate longitudinal area on disc and very sparse and small punctation on basal third of pronotum (paratype); punctation of elytra very dense and deep, coarser and smaller on prescutellar area; abdominal tergites without visible punctures.

Head 1.6–1.7 times as wide as long, slightly convex posteriorly. Distance between ocelli one and half times as long as distance betwen ocellus and posterior margin of eye. Apical segment of maxillary palp slightly longer than preceding segment. Length × width of antennomeres (holotype): 1: 0.12 × 0.05; 2: 0.13 × 0.04; 3: 0.12 × 0.03; 4: 0.10 × 0.04; 5–7: 0.11 × 0.04;8–10: 0.10 × 0.05;11: 0.14 × 0.06.

Pronotum 1.5–1.6 times as wide as long, widest in middle, evenly narrowed both posteriad and anteriad; anterior angles widely rounded, indistinctly protruded anteriad; posterior angles widely rounded.

Elytra distinctly wider than long, reaching middle or apical part of abdominal tergite IV, 1.8 times as long as pronotum.

Metatibia about 1.2 times as long as metatarsus.

Male ( Fig. 16 ). Protarsomeres 1–4 wide. Medial margin of apical part of protibia with two rows of nine short peg setae; mesotibia markedly curved mediad, with dense row of twenty four short thorns. Apical margin of abdominal tergite VIII straight. Apical margin of abdominal sternite VIII widely rounded. Aedeagus ( Fig. 20 ) with median lobe strongly narrowed apicad, with narrow and elongate apical portion; parameres narrow, distinctly exceeding median lobe, indistinctly widened apicad, with small apical and preapical setae; internal sac with three fields of fine thorns in apical half, with two pairs of moderately large thorns in middle portion and with characteristic long, bifurcate structure in basal half. Aedeagus laterally as in Fig. 21 .

Female. Protarsomeres 1–4 moderately narrow. Medial margin of protibia and mesotibia without modifications. Abdominal tergite VIII and sternite VIII with rounded apical margin.

Comparative notes. Based on the body size, coloration, general shape of the aedeagus and the presence of similar structures within internal sac, A. propinquum sp.n. is similar to A. longilobatum sp.n., from which it differs by shorter apical antennomeres, elytra and apical portion of the median lobe, and by the details of the internal sac.

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

Bionomics. Specimens were collected at elevation 1700 m a.s.l. Collection details are not available.

Etymology. The specific epithet is a Latin adjective propinquus, - a, - um (related).It refers to the similarity of this species with some of its congeners.

Figures

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 16–19. Habitus of Amphichroum (males): 16–A. propinquum sp.n. (holotype), 17–A. rotundatum sp.n. (holotype), 18–A. schuelkei sp.n. (paratype), 19–A. squamosum sp.n. (holotype). Scale bar: 1.0 mm.

FIGURES 20–23. Aedeagus of Amphichroum propinquum sp.n.(20–21: holotype) and A. rotundatum sp.n. (22–23: paratype): 20, 22–parameral view, 21, 23–lateral view. Scale bar: 0.1 mm.