Amphichroum maculosum 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 : 385-387

Amphichroum maculosum Shavrin & Smetana , sp.n.

( Figs. 4 , 14–15 , 41 )

Type material examined: Holotype ♂: ‘ CHINA (Yunnan) Dali Bai Auton. Pref., | Diancang Shan W Dali | 25°41'50.9-52''N / 100°06'01.7-28.3''E | ca 2960-2980 m (former stone pit, | in gravel /under stones) | 6.IX.2009 D.W. Wrase [31]’ <rectangular label, printed >, ‘ HOLOTYPE | Amphichroum | maculosum sp.n. | Shavrin A. & Smetana A. des. 2018’ <red rectangular label, printed> ( CSC) .

Paratypes: 1 ♂ [specimen dissected; abdomen glued under the specimen], 3 ♀♀: same data as the holotype (1 ♂: CS; 3 ♀♀: CSC). All paratypes with red rectangular label ‘ PARATYPE | Amphichroum | maculosum sp.n. | Shavrin A. & Smetana A. des. 2018’.

Description. Measurements (n=5): HW: 0.49–0.56; HL: 0.22–0.24; AL (holotype): 0.85; OL: 0.13–0.15; PL: 0.50–0.57; PW: 0.75–0.90; ESL: 0.80–1.05; EW: 1.00–1.24; AW: 0.85–1.10; MTbL (holotype): 0.45; MTrL (holotype): 0.39 (MTrL 1–4: 0.22; MTrL 5: 0.17); AedL: 0.57; TL: 2.00 (holotype) –2.35.

Head and pronotum yellow-brown; posterior portion of head, median part of neck and scutellum reddishbrown; disc of pronotum with moderately wide reddish-brown spot (indistinct in some paratypes) beginning from anterior margin, stretching and gradually narrowing toward basal margin of pronotum; antennomeres 1–4, elytra and legs yellow; maxillary palpi and abdomen reddish-brown to brown (some paratypes with yellow-brown abdomen, with yellow apical portion and paratergites). Forebody without distinct microsculpture except for posterior part of infraorbital ridges of head with indistinct diagonal and transverse meshes, neck and scutellum with distinct isodiametric microsculpture; abdominal tergites with distinct isodiametric microsculpture. Middle and posterior portions of head with irregular, small and moderately deep punctation; pronotum with dense and irregular small punctation slightly larger as that on head, distinctly sparser on medio-posterior third and lateral portions; punctation of elytra distinctly larger and deeper than that in pronotum, markedly smaller and denser on prescutellar area; abdominal tergites with irregular and very indistinct small punctures.

Head more than twice as wide as long, flattened in middle. Ocelli very large, indistinct due the same coloration with surface of head, located at level of posterior fourth of eyes, distance between ocelli about as long as distance between ocellus and posterior margin of eye. Apical segment of maxillary palp 1.1-1.2 times as long as preceding segment, gradually narrowed apicad from base. Antenna moderately short, reaching basal margin of elytra when reclined, with antennomeres gradually widened towards apex; length × width of antennomeres (holotype): 1: 0.11 × 0.04; 2: 0.07 × 0.04; 3: 0.07 × 0.02; 4–6: 0.06 × 0.03; 6: 0.07 × 0.04; 7–8: 0.07 × 0.05; 9–10: 0.07 × 0.06; 11: 0.13 × 0.06.

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

Elytra markedly wider than long, significantly widened apicad, reaching apical margin of abdominal tergite V, 1.6–1.8 times as long as pronotum.

Male ( Fig. 4 ). Pronotum wide. Protarsomeres 1–4 very wide. Medial margin of apical part of protibia with two parallel rows of five to six short peg setae; mesotibia distinctly curved mediad, with dense row consisting of twelve to fourteen short and wide thorns. Abdominal tergite VIII with straight apical margin. Abdominal sternite VIII with slightly sinuate apical margin. Aedeagus ( Fig. 14 ) with median lobe markedly narrowed toward acute apex; parameres narrow, markedly exceeding apex of median lobe, with narrow setiferous lobes, with a pair of small apical and preapical setae; internal sac moderately long, with paired, very large and elongate structures in basal part and two elongated apical thorns. Aedeagus laterally as in Fig. 15 .

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

Comparative notes. Amphichroum maculosum sp.n. differs from the remaining species of the genus by the presence of longitudinal reddish-brown spot on the pronotum. Based on the general shape of the apical part of the aedeagus and parameres, A. maculosum sp.n. is similar to A. milkense Coiffait, 1984 ( Nepal) , A. monticola Cameron, 1928 ( Bhutan, Xizang) and A. reticulatum Coiffait, 1978 ( Bhutan) , but it differs by the smaller body, paler forebody, wider basal portion of the aedeagus and different structures of the internal sac.

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

Bionomics. Specimens were collected at elevations from 2960 to 2980 m a.s.l. from gravel and from under stones near a former stone pit.

Etymology. The specific epithet is the Latin adjective maculosus, - a, - um (with spot or spots). It refers to the presence of the spot on disc of pronotum.

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 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 12–15.Aedeagus of Amphichroum longilobatum sp.n.(12–13: paratype) and A. maculosum sp.n. (14–15: paratype): 12, 14–parameral view, 13, 15–lateral view. Scale bar: 0.1 mm.