Anthobium explanatum Shavrin & Smetana, 2019

Shavrin, Alexey V. & Smetana, Aleš, 2019, A revision of Eastern Palaearctic Anthobium Leach, 1819 (Coleoptera: Staphylinidae: Omaliinae: Anthophagini). III. Consanguineum, crassum and reflexum groups, and an additional species of the fusculum group, Zootaxa 4688 (4), pp. 451-482 : 465-467

Anthobium explanatum Shavrin & Smetana , sp.n.

( Figs. 58 , 64 , 69–70 )

Type material examined: Holotype ♂: ‘P.R. CHINA, Sichuan, | E slope Gongga Shan , | N29°34’31’’ E102°00’ | 31’’, 23.vi.2011, 2832m | sift26, V.Grebennikov’ <rectangular label, printed >, ‘ HOLOTYPE | Anthobium | explanatum sp.n. | Shavrin A. & Smetana A. 2017’ <red rectangulat label, printed> ( NSMT) .

Paratype ♀: same data as the holotype, with additional red rectangular printed label ‘ PARATYPE | Anthobium | explanatum sp.n. | Shavrin A.V. & Smetana A. 2018’ ( CS) .

Description. Measurements (n=2): HW: 0.72; HL: 0.42; AL: 1.33; OL: 0.15; PL: 0.57; PW: 1.40; ESL: 1.42– 1.52; EW: 1.67–1.76; AW: 1.25–1.28; MTbL (holotype): 0.62, MTrL (holotype): 0.29 (MTrL 1–4: 0.17; MTrL 5: 0.12); AedL: 0.62; TL: 3.20–3.27 (holotype).

Body and antennomeres 6–11 yellow-brown, with somewhat darker head; mouthparts, antennomeres 1–5, lateral sides of pronotum and elytra, legs and apical tergites of abdomen yellow. Middle portion of head with irregular, fine, sparse punctation, with moderately wide transverse impunctate portions between grooves in front of ocelli, punctation markedly denser and deeper on laterobasal portions between ocelli and eyes, infraorbital ridges with markedly larger, denser and deeper, irregular punctation, with some punctures merging each other; pronotum with moderately dense, deep punctation, markedly larger than that on middle of head, denser on medioapical portion, sparser and finer on mediobasal, and sparser and deeper on lateral portions; scutellum with several very fine punctures; punctation of elytra dense, slightly larger and deeper than that on pronotum in middle, sparser and finer on parascutellar and medioapical portions, distinctly sparser on lateral portions, each elytron along suture bearing three very vague and tangled longitudinal rows of moderately fine punctures; abdominal tergites with very indistinct and sparse fine punctation. Habitus as in Fig. 58 .

Head 1.7 times as wide as long; middle portion of head with distinct, wide triangular impression between eyes at posterior third, with indistinct grooves in front of ocelli, reaching posterior part of eye, and with distinct, narrow transverse impression between ocelli; lateral parts of head with moderately wide surface between acute postocular ridge and posterior margin of eye as long as three nearest combined ommatidia; anterior portion between antennal insertion and anterior margin of eye with wide, indistinct semicircular notch. Ocelli large, situated slightly behind of level of postocular ridges. Antenna moderately long, reaching one-fourth of elytra when reclined; length × width of antennomeres (holotype): 1: 0.16 × 0.07; 2: 0.12 × 0.06; 3: 0.13 × 0.05; 4: 0.11 × 0.05; 5–7: 0.12 × 0.06; 8: 0.11 × 0.06; 9: 0.10 × 0.07; 10: 0.09 × 0.07; 11: 0.15 × 0.08.

Pronotum markedly more than twice as wide as long, about twice as wide as head, widest in middle; anterior angles widely rounded, strongly protruded anteriad; posterior angles acute; lateral margins with three to four irregular, tooth-shaped projections, markedly stronger than those in A. crassum sp.n., and with additional very small flattened lateral crenulation on edges; middle portion wide and distinctly elevated, with indistinct longitudinal impression, and very deep semioval impression on mediobasal third; lateral portions very wide and explanate, each with very deep and large oval pit in the middle.

Elytra with convex middle portion, combined about as wide as long, slightly or distinctly more than twice as long as pronotum, markedly widened apicad from middle, reaching middle of abdominal tergite V or VI, with somewhat straight apical margins; shoulders wide, indistinctly protruded anteriad; flattened lateral portions of elytra markedly explanate, very wide, about twice as wide as convex middle portion, latero-apical margins with moderately large acute crenulation, more flattened and reduced in middle; middle portion of each elytron with two to three very indistinct longitudinal elevations between punctures, more visible in basal half. Wings very short.

Abdomen with very indistinct small round tomentose wing-folding spots in about middle of tergite V.

Male. Apical margins of abdominal tergite VIII and sternite VIII slightly emarginated. Aedeagus ( Fig. 69 ) narrow, with widely truncate apex of median lobe; parameres very long, narrow, markedly exceeding apex of median lobe, with two small apical and preapical setae; internal sac narrow and moderately long. Aedeagus laterally as in Fig. 70 .

Female. Apical margin of abdominal tergite VIII straight. Apical margin of abdominal sternite VIII rounded.

Comparative notes. Anthobium explanatum sp.n. differs from the remaining species of the crassum -group by the paler coloration, by the strong tooth-shaped projections on lateral margins of the pronotum, by the very wide lateral portions of short elytra, as well as by external and internal characters of the aedeagus.

Distribution. The species is known only from the type locality in Gongga Shan range in Sichuan, China ( Fig. 64 ).

Bionomics. All specimens were taken by sifting forest litter at elevation 2832 m a.s.l.

Etymology. The specific epithet is the Latin adjective explanatus, - a, - um (widened). It refers to the markedly widened pronotum and elytra of the species.

Figures

FIGURE 64. Distribution of Anthobium crassum (black circles), A. crenulatum (black square), A. explanatum (black rhomb), and A. farkaci (black triangle) in the south-western China.

FIGURES 56–59. Habitus of species of Anthobium crassum-group: 56—A. crassum (holotype), 57—A. crenulatum (holotype), 58—A. explanatum (holotype), 59—A. farkaci (holotype). Scale bar: 1.0 mm.

FIGURES 69–72. Aedeagus of Anthobium explanatum (69–70: paratype) and A. farkaci (71–72: holotype): 69, 71—parameral view, 70, 72—lateral view. Scale bar: 0.1 mm.