Amphichroum reticulatum Coiffait, 1978

Shavrin, Alexey V., 2022, New species and records of Amphichroum Kraatz, 1857 from China and the Himalayan Region (Coleoptera: Staphylinidae: Omaliinae: Anthophagini), Zootaxa 5190 (4), pp. 575-583 : 581-582

Amphichroum reticulatum Coiffait, 1978

( Figs. 9–10 , 12 )

Amphichroum reticulatum Coiffait, 1978: 149

Type material examined. Holotype ♂ (dissected): ‘Sampa-Kotoka | 1400–2600m’ <printed>, ‘Nat.-Hist.Museum | Basel— Bhutan | Expedition 1972’ <printed>, ‘HOLOTYPE’ <red, printed>, ‘ Amphichroum | reticulatum | H. COIFFAIT det. 19[printed]77’ <handwritten>, ‘ Amphichroum | reticulatum Coiffait, 1978 | Shavrin A. V. det. 2022’ ( NHMB).

Redescription. Measurements: HW: 0.75; HL: 0.42; AL: 2.24; OL: 0.20; PL: 0.75; PW: 1.22; ESL: 1.35; EW: 1.53; AW: 1.35; MTbL: 0.82; MTrL: 0.77 (MTrL 1–4: 0.45; MTrL 5: 0.32); AedL: 0.85; TL: 3.95.

Habitus as in Fig. 12 . Forebody, antennomeres 4–11 and legs yellow-brown (middle portions of elytra somewhat darker; paratergites slightly paler); mouthparts, antennomeres 1–3, lateral portions of pronotum and apical tarsomeres yellow. Head with dense and regular microsculpture, transverse in frontal portion and isodiametric in middle and on infraorbital ridges; neck with very dense and coarse isodiametric microreticulation; pronotum with regular, very dense, small isodiametric microsculpture; visible part of scutellum with dense transverse meshes; elytra with indistinct, fine isodiametric meshes; abdominal tergites with dense microreticulation, transverse on abdominal tergites IV–VI or isodiametric on tergites VII–VIII. Head without visible punctation; middle portion of pronotum with indistinct, very sparse and fine punctation, slightly denser and larger in basal portion; elytra with moderately large and dense punctation, finer in middle portion; abdomen without visible punctures. Body without setation except for frontal portion of head with several moderately short setae, and pronotum with very short setae along lateral margins.

Head 1.7 times as broad as long, slightly flattened in middle; anteocellar foveae narrow, moderately deep and very long, almost exceeding supra-antennal elevation. Ocelli moderately large, distance between ocelli slightly shorter than distance between ocellus and posterior margin of eye. Apical segment of maxillary palpi 1.3 times as long as preceding segment. Antennomere 4 distinctly shorter and slightly broader than 3, 5–7 slightly shorter and broader than 4, 8–10 slightly shorter than 7, apical antennomere about 1.3 times as long as 10.

Pronotum 1.6 times as broad as long, 1.6 times as broad as head, widest in middle, gradually narrowed both apicad and posteriad; widely rounded anterior angles strongly protruded apicad.

Elytra slightly broader than long, reaching apical margin of abdominal tergite IV.

Metatibia slightly longer than very long metatarsus.

Abdomen distinctly narrower than elytra.

Male. Medial margin of apical half of protibia with two parallel rows of eight short peg setae; mesotibia strongly curved mediad, with dense row of about 20 short thorns. Apical margin of abdominal tergite VIII rounded. Apical margin of abdominal sternite VIII slightly concave. Aedeagus with wide basal portion, strongly narrowed apicad toward moderately narrow median lobe with subacute apex; parameres narrow, significantly exceeding apex of median lobe, with two short apical and two preapical setae; internal sac long, without additional large sclerites ( Fig. 9 ). Lateral aspect of the aedeagus as in Fig. 10 .

Female unknown.

Comparative notes. Based on the general shape of the body and the aedeagus, it is similar to the Himalayan A. monticola Cameron, 1928 , A. nepalicum (Coiffait, 1982) and A. pindarense Champion, 1920 . From A. monticola and A. nepalicum it differs by the more transverse pronotum, slightly longer elytra, and narrower apical portion of the median lobe. Additionally, from A. nepalicum it can be distinguished by the larger body. From A. pindarense it differs by the slightly broader apical portion of the median lobe and the absence of large sclerotized teeth in the internal sac.

Distribution. Amphichroum reticulatum is at present known only from the type locality in Sampa-Kotoka, Bhutan.

Bionomics. The holotype was collected at elevation between 1400–2600 m a.s.l. The detailed ecological data are unknown.

Figures

FIGURES 3–10. Aedeagus of Amphichroum (Figs. 3–5: A. discolor; Fig. 6 (apical portion): A. rotundatum; Figs. 7–8: A. grandidentatum; Figs. 9–10: A. reticulatum): 3–4, 6–7, 9–parameral view, 5, 8, 10–lateral view. Scale bar: 0.1 mm.

FIGURES 11–12. Habitus of Amphichroum: 11–A. grandidentatum, 12–A. reticulatum. Scale bar: 1.0 mm.