Amphichroum brachypterum, Shavrin, 2022

Shavrin, Alexey V., 2022, Two new species and additional records of Amphichroum Kraatz, 1857 from Nepal China and India (Coleoptera: Staphylinidae: Omaliinae: Anthophagini), Zootaxa 5104 (1), pp. 143-148 : 144-145

Amphichroum brachypterum sp. n.

( Figs. 1 , 3–4 )

Type material examined: HOLOTYPE: NEPAL: ♂ (left apical antennomere missing; dissected): ‘BRITISH NEPAL [underlined by yellow] | Timure. | 10,500ft., 1949 | O. Polunin’ <handwritten in black>, ‘British Nepal | Expedition.1949. | B.M.1949–637.’ <printed>, ‘HOLOTYPE | Amphichroum | brachypterum sp. n. | Shavrin A.V. des. 2022’ <red, printed> ( BMNH).

Paratypes: 1 ♀ (antennomeres 3–11 and apical segments of the abdomen missing): same data as the holotype, with red printed label: ‘ PARATYPE | Amphichroum | brachypterum sp. n. | Shavrin A. V. des. 2022’ ( BMNH).

Description. Measurements (n=2): HL: 0.30; HW: 0.46–0.50; AL (holotype): 1.07; OL: 0.12; PL: 0.42–0.51; PW: 0.72–0.81; ESL: 0.72–0.79; EW: 1.00–1.10; AW: 0.93–1.17; MTbL (holotype): 0.40; MTrL (holotype): 0.35 (MTrL 1–4: 0.20; MTrL 5: 0.15); AedL: 0.50; TL: 2.60–2.70 (holotype).

Habitus as in Fig. 1 . Forebody yellow-brown; abdomen reddish-brown (holotype); antennomeres 5–11 brown; mouthparts, antennomeres 1–4 and legs yellow (apical maxillary palpomeres darker). Body glossy; frontal portion of head with distinct, very dense and transverse microsculpture, middle portion with dense isiodiametric microreticulation, infraorbital ridges with transverse meshes (middle portion of head of paratype with very indistinct transverse microreticulation); neck with dense transverse meshes; pronotum with indistinct meshes in medioapical third; scutellum with fine, transverse microsculpture; abdomen with dense isodiametric microreticulation. Head without distinct punctation except of middle portion with indistinct and sparse, fine punctures; punctation of pronotum moderately large, deep and sparse, sparser in mediobasal and lateral portions; punctation of elytra denser and deeper than that in pronotum, finer in parascutellar area and along suture; abdominal tergites without distinct punctation except of tergites V–VII with very fine and sparse punctures. Forebody with moderately dense and sparse setation, denser on pronotum and elytra; abdominal tergites with very short and sparse setae.

Head 1.5–1.6 times as broad as long, slightly flattened in middle, with slightly elevated infraorbital ridges; anteocellar foveae (grooves in front of ocelli) narrow, moderately deep and long, somewhat parallel-sided, almost reaching level of anterior margin of large and convex eyes. Ocelli very small, indistinct, located about level of posterior margin of eyes near narrow occipital furrow, distance between ocelli about as long as distance between ocellus and posterior margin of eye. Apical maxillary palpomere about 1.3 times as long as preceding segment, sharply narrowed from middle toward subacute apex. Antenna reaching basal part of elytra when reflexed; basal antennomere oblong, about as long as broad and as long as antennomere 2, 3 slightly shorter and narrower than 2, 4 distinctly shorter and slightly broader than 3, 5–6 slightly longer and broader than 4, 7 slightly longer and broader than 6, 8–9 broader than 7, 10 slightly broader than 9, apical antennomere about 1.4 times as long as preapical antennomere, from widest middle gradually narrowed toward subacute apex.

Pronotum moderately small, transverse, 1.5–1.7 times as broad as long, 1.5–1.6 times as broad as head, widest in middle, slightly more narrowed posteriad than anteriad; anterior angles widely rounded, not protruded anteriad; posterior angles widely rounded; lateral portions moderately wide, flattened, slightly explanate and gradually broadened posteriad.

Elytra short, transverse, distinctly broader than long, significantly broadened apicad, reaching apical margin of abdominal tergite II, 1.5–1.7 times as long as pronotum, with widely rounded apical margins. Hind wings moderately short.

Legs moderately long; metatibia distinctly longer than metatarus; apical metatarsomere slightly shorter than previous four segments.

Abdomen slightly narrower than elytra, without visible tomentose spots (wing-folding patches) in middle of tergite IV and palisade fringe on apical margin of tergite VII.

Male. Protarsomeres 1–4 very wide. Medial margin of inner side of protibia with two parallel rows of six moderately strong peg setae; mesotibia strongly curved mediad, with dense row of 16 short thorns beginning from basal side of bend and stretching to apex of mesotibia. Apical margins of abdominal tergite VIII rounded. Apical margin of abdominal sternite VIII slightly concave. Aedeagus with wide basal bulb, strongly narrowed toward subacute apex; parameres narrow, long, slightly exceeding apex of median lobe, each with two apical and two preapical small setae; internal sac long and moderately wide, with large, suboval structure in basal portion ( Fig. 3 ). Lateral aspect of aedeagus in Fig. 4 .

Female. Protarsomeres 1–4 narrow. Medial margin of protibia without peg setae; mesotibia without modifications.

Comparative notes. Amphichroum brachypterum sp. n. differs from all known species of the genus by the shorter elytra, larger punctation of the pronotum and the elytra, and external and internal morphology of the aedeagus.

Distribution. The new species is known only from the type locality in central Nepal.

Etymology. The specific epithet is an adjective of the Latin brachypterus, - a, - um (short-winged). It alludes to the shortened elytra and hind wings.

Figures

FIGURES 1–2. Habitus of Amphichroum (males): 1–A. brachypterum (holotype), 2–A. cuccodoroi (paratype). Scale bars: 1.0 mm.

FIGURES 3–6. Aedeagus of Amphichroum brachypterum (3–4: holotype) and A. cuccodoroi (5–6: paratype): 3, 5–parameral view, 4, 6–lateral view. Scale bars: 0.1 mm.