Amphichroum assingi 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 : 382-383

Amphichroum assingi Shavrin & Smetana , sp.n.

( Figs. 2 , 8–10 , 41 )

Type material examined: Holotype ♂ [specimen without left metatarsus]: ‘ CHINA: Yunnan | Pass 50 km W from | Judian , 10- 13.6.2005 | Ivo Jeniš’ <rectangular label, printed >, ‘ HOLOTYPE | Amphichroum | assingi sp.n. | Shavrin A. & Smetana A. des. 2018’ <red rectangular label, printed> ( CA) .

Paratypes: 1 ♂, 1 ♀: same data as the holotype (1 ♂: CAS; 1 ♀: CA). All paratypes with red rectangular label ‘ PARATYPE | Amphichroum | assingi sp.n. | Shavrin A. & Smetana A. des. 2018’.

Description. Measurements (n=3): HW: 0.70–0.82; HL: 0.37–0.47; AL (holotype): 1.32; OL: 0.18–0.20; PL: 0.67–0.79; PW: 1.07–1.33; ESL: 1.25–1.55; EW: 1.22–1.54; AW: 1.20–1.55; MTbL (holotype): 0.77; MTrL (holotype): 0.60 (MTrL 1–4: 0.35; MTrL 5: 0.25); AedL (holotype): 0.85; TL: 3.55 (holotype)–4.95 (holotype: 3.55).

Head, disc of pronotum and apical segment of maxillary palpomere reddish-brown; mouthparts, antennomeres 1–3, lateral portions of pronotum, legs, elytra and paratergites yellow to yellowish-brown; antennomeres 4–11 brown; abdomen reddish-brown to brown (female paratype) immature, yellow-brown with slightly darker head). Head with dense transverse microsculpture, somewhat diagonal on posterior portions of infraorbital ridges; neck with coarse isodiametric microsculpture; pronotum with dense, and coarse isodiametric microsculpture, sometimes sparser on medio-basal third (holotype); scutellum with transverse coarse meshes; elytra with indistinct isodiametric microsculpture, more distinct and coarser near scutellum. Head with indistinct to distinct punctation, denser and deeper on posterior portion between grooves and on infraorbital ridges (one paratype without punctation except for several very indistinct punctures on infraorbital ridges); pronotum with indistinct to distinct small punctation, sparser on medio-basal third; scutellum without punctures; punctation of elytra dense, moderately large and deep.

Head 1.7–1.8 times as wide as long, slightly convex posteriorly; grooves in front of ocelli very deep and wide, narrowing apicad. Ocelli located lower of level of posterior margin of eyes, distance between ocelli distinctly shorter than distance between ocellus and posterior margin of eye. Eyes large and strongly convex. Length × width of antennomeres (holotype): length × width of antennomeres (holotype): 1: 0.16 × 0.05; 2: 0.12 × 0.05; 3: 0.12 × 0.04; 4: 0.10 × 0.05; 5–10: 0.11 × 0.06; 11: 0.16 × 0.06.

Pronotum 1.5–1.6 times as wide as long, evenly narrowed both anteriad and posteriad (holotype) or slightly more narrowed anteriad than posteriad; anterior angles rounded, distinctly protruded anteriad; lateral portions markedly wide.

Elytra slightly longer than wide, indistinctly widened from middle, reaching basal margin of abdominal tergite IV, 1.8–1.9 times as long as pronotum.

Metatibia 1.2 times as long as metatarsus.

Abdomen slightly narrower or wider than elytra.

Male ( Fig. 2 ). Protarsomeres 1–4 wide. Medial margin of apical part of protibia with two parallel rows of six to eight short peg setae; mesotibia moderately curved mediad, with dense row consisiting of sixteen to eighteen short thorns. Apical margin of abdominal tergite VIII straight. Apical margin of sternite VIII slightly sinuate. Aedeagus ( Fig. 8 ) with narrow median lobe, gradually narrowing to subacute apex; parameres narrow, significantly exceeding apex of median lobe, with two pairs of small apical and preapical setae; internal sac ( Fig. 9 ) very long, with fields of large thorns in apical and basal portions and with ring-like structure in basal part. Aedeagus laterally as in Fig. 10 .

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

Comparative notes. Based on the body size, the elongated parameres and on the presence of fields of large thorns in the internal sac, A. assingi sp.n. is similar to A. rotundatum sp.n. and A. tibetanum sp.n., from which it differs by the shape of anterior angles of the pronotum distinctly protruded anteriad, by the narrowed apical portion of the median lobe and by structures of the internal sac.

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

Bionomics. The detailed ecological data are unknown.

Etymology. Patronymic, the species is named to honour our colleague, Volker Assing of Hannover, Germany.

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 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.