Amphichroum longilobatum 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 : 383-385

Amphichroum longilobatum Shavrin & Smetana , sp.n.

( Figs. 3 , 12–13 , 41 )

Type material examined: Holotype ♂: CHINA: ‘ Sichuan | Erlangshan E Luding | 2600-2700 m, 14.-15. VI .2003, | leg. S. Murzin’ <rectangular label, printed>, ‘ HOLOTYPE | Amphichroum | longilobatum sp.n. | Shavrin A. & Smetana A. des. 2018’ <red rectangular label, printed> ( CSC) .

Paratypes: same data as the holotype: 5 ♂♂, 1 ♀: (1 ♂: CS; 4 ♂♂, 1 ♀: CSC) ; Paratypes: 28 ♂♂, 30 ♀♀: ‘ CHINA: W-Sichuan 1999 | Ya `an Prefecture , Tianquan Co. | E Erlang Shan Pass, 2900m | 9km SE Luding, 29°52N, | 102°18E, geklopft, Handfang | 22.VI., leg. M. Schülke’ <rectangular label, printed>, ‘ Sammlung | M. Schülke | Berlin’ <green rectangular label, printed> (1 ♀: CA; 3 ♂♂, 3 ♀♀: CS; 25 ♂♂, 26 ♀♀: CSC). All paratypes with red rectangular label ‘ PARATYPE | Amphichroum | longilobatum sp.n. | Shavrin A. & Smetana A. des. 2018’.

Description. Measurements (n=65): HW: 0.54–0.71; HL: 0.30–0.35; AL(holotype): 1.01; OL: 0.15–0.17; PL: 0.57–0.74; PW: 0.87–1.10; ESL: 1.02–1.29; EW: 1.15–1.49; AW: 1.00–1.11; MTbL(holotype): 0.62; MTrL(holotype): 0.47 (MTrL 1–4: 0.27; MTrL 5: 0.20); AedL: 0.67–0.75; TL: 2.10–3.65 (holotype: 2.75).

Forebody yellow to yellow-brown, sometimes with reddish-brown head and middle part of pronotum; mouthparts, antennomeres and legs yellow (some paratypes with reddish-brown apical segment of maxillary palpi); abdomen reddish-brown, sometimes with yellow to yellow-brown paratergites and apical portion. Disc of pronotum with indistinct transverse microsculpture; scutellum with distinct and sometimes coarse transverse meshes. Middle portion of head and infraorbital ridges with irregular small punctation; middle portion of neck without visible punctures; pronotum with moderately dense small punctation as that on head, usually distinctly sparser on medio-basal portion; scutellum without or with several very small punctures.

Head distinctly transverse, about twice as wide as long, markedly flattened in middle, sometimes slightly convex on posterior portions of infraorbital ridges. Apical segment of maxillary palp 1.2–1.3 times as long as preceding segment, acutely narrowed apicad from base. Length × width of antennomeres (holotype): 1: 0.13 × 0.05; 2: 0.10 × 0.05; 3: 0.10 × 0.03; 4: 0.07 × 0.04; 5: 0.08 × 0.04;6–7: 0.07 × 0.05; 8–10: 0.08 × 0.05;11: 0.15 × 0.06.

Pronotum 1.4–1.5 times as wide as long, widest in middle, evenly narrowed both posteriad and apicad; apical margin straight or widely rounded.

Elytra distinctly longer than wide, markedly widened apicad, reaching apical margin of abdominal tergite IV– V or basal margin of tergite VI, 1.7 times as long as pronotum.

Metatibia 1.3 times as long as metatarsus.

Male ( Fig. 3 ). Protarsomeres 1–4 very wide. Medial margin of apical part of protibia with two parallel rows of five to seven short peg setae; mesotibia strongly curved mediad, with dense row of sixteen to twenty three very short and wide thorns. Abdominal tergite VIII and sternite VIII slightly sinuate. Aedeagus ( Fig. 12 ) with median lobe strongly narrowed apicad, with very narrow and markedly elongate apical portion; parameres narrow, slightly exceeding apex of median lobe, with two pairs of apical and preapical short setae; internal sac with two pairs of large conical thorns in middle portion and with two very long curved structures in basal half and with additional thin structure basally. Aedeagus laterally as in Fig. 13 .

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, shape of markedly elongate apical portion of median lobe and the presence of two elongate sclerotized structures in basal portion of the internal sac, A.longilobatum sp.n. is most similar to A. propinquum sp.n., from which it differs by somewhat elongated apical antennomeres, longer elytra, more slender apical portion of median lobe, shorter parameres and by the details of the internal sac.

Distribution. The new species is known from two locations ( Fig. 41 ) in Erlang Shan range in Sichuan, China.

Bionomics. Specimens were collected at elevations from 2600 to 2900 m a.s.l.by shaking of flowering bushes.

Etymology. The specific epithet is a combination of Latin adjective longus, - a, - um (long) and and lobatus, -a, -um (lobed). It refers to elongate apical portion of median lobe of the aedeagus.

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.