Amphichroum feldmanni Shavrin, 2019

Shavrin, Alexey V., 2019, A new species and records of the genus Amphichroum Kraatz, 1857 (Coleoptera: Staphylinidae: Omaliinae: Anthophagini) from Sichuan, China, Zootaxa 4701 (2), pp. 197-200 : 197-200

Amphichroum feldmanni Shavrin sp.n. ( Figs. 1–4 )

Type material examined: Holotype ♂ [a plastic plate with aedeagus in Canada balsam was pinned under the card with the beetle; abdominal tergite VIII, sternite VIII and apical segment are glued on the same card under the specimen; left antennomere is missing]: ‘ CHINA, N-Sichuan, | Huanglong Shan , 2611 m | Sanluogou vill. | 32°46’50’’N, 103°55’25’’E | 15–17.VI.2018,leg. Reuter’ <rectangular label, printed >, ‘ HOLOTYPE | Amphichroum | feldmanni sp.n. | Shavrin A.V. des. 2019’ ( CF) . Paratype: 1 ♀: same data as the holotype, with red rectangular label ‘ PARATYPE | Amphichroum | feld- manni sp.n. | Shavrin A.V. des. 2019’ (temporarily in CF, to be eventually deposited in Museum für Naturkunde, Berlin, Germany) .

Description. Measurements (n=2, in mm): maximum width of head including eyes: 0.73–0.74; length of head (from base of labrum to neck constriction along head midline): 0.50; length of antenna (holotype): 1.56; ocular length (longitudinal): 0.20–0.22; length of pronotum: 0.72–0.75; maximum width of pronotum: 1.10–1.20; sutural length of elytra (length of elytra from the apex of scutellum to the posterior margin of sutural angle): 1.32–1.47; maximum width of elytra: 1.35–1.50; maximum width of abdomen: 1.42–1.55; length of metatibia (holotype): 0.92; length of metatarsus (holotype): 0.67 (metatarsomeres 1–4: 0.40; metatarsomere 5: 0.27); length of aedeagus (from base of the median lobe to apex of parameres): 0.87; total length (from anterior margin of clypeus to apex of abdomen): 4.65 (holotype)–4.85.

Middle portion of head and pronotum brown; apical portion of head and elytra yellow to yellow-brown; abdomen, apex of antennomere 3 and antennomeres 4–11 dark-brown; mouthparts, antennomeres 1–3 and legs yellow (paratype with head, pronotum and abdomen reddish-brown). Head with distinct and very dense isodiametric microsculpture, more transverse between grooves and ocelli, more or less rounded on infraorbital ridges and neck; middle portion of pronotum with very dense microsculpture, somewhat finer than that in head; scutellum with moderately large transverse meshes; elytra without microsculpture; abdomen with regular isodiametric microsculpture, more distinct in tergites III–V. Middle portion of head with markedly sparse, very small punctures; middle portion of pronotum with fine, sparse and regular punctation; punctation of elytra dense, large and deep, distinctly smaller on prescutellar area; abdominal tergites with indistinct fine punctures. Head 1.4 times as wide as long, flattened in middle and slightly convex on infraorbital ridges; grooves in front of ocelli deep and long, diagonally stretching toward antennal bases. Ocelli moderately large and convex, located lower of level of posterior margins of eyes near occipital furrow, distance between ocelli distinctly narrower than distance between ocellus and posterior margin of eye. Eyes large and convex. Apical segment of maxillary palp 1.3 times as long as preceding segment, sharply narrowed apicad from basal third. Antenna moderately long, reaching one-third of elytral length when reclined; length × width of antennomeres (holotype): 1: 0.20 × 0.07; 2: 0.15 × 0.06; 3: 0.17 × 0.05; 4: 0.12 × 0.06; 5: 0.12 × 0.07; 6–7: 0.11 × 0.07; 8–10: 0.11 × 0.08; 11: 0.25 × 0.09. Pronotum 1.5–1.6 times as wide as long and head, widest at about middle, gradually narrowed both posteriad and anteriad; anterior angles rounded, protruded apicad; posterior angles widely rounded; lateral flattened portions wide, slightly explanate. Elytra slightly wider than long, indistinctly widened apicad, reaching apical margin of abdominal tergite III, 1.8–1.9 times as long as pronotum. Legs moderately long; metatibia 1.3 times as long as metatarsus, with several long strong thorns on inner surface and long setae between them. Abdomen slightly wider than elytra, with a pair of very indistinct tomentose spots in middle of tergite IV, with narrow palisade fringe on apical margin of tergite VII.

Male ( Fig. 1 ). Pronotum moderately elongate, with anterior angles markedly protruded apicad. Protarsomeres 1–4 distinctly wide. Antennomeres 4–10 markedly elongate. Medial margin of apical part of protibia with two parallel rows of several short peg setae; mesotibia strongly curved mediad, with dense row of 17–20 very short and wide thorns beginning from apical third of bend and stretching to apex of metatibia. Abdominal tergite VIII and sternite VIII slightly rounded apically. Aedeagus ( Fig. 3 ) with median lobe gradually narrowed toward moderately small rounded apex; parameres exceeding apex of median lobe, with wide apical portions, each with two pairs of apical and preapical setae; internal sac long, with long parallel rows of thorns in apical half and with wide field of strongly sclerotized thorns in basal portion. Aedeagus laterally as in Fig. 4 .

Female ( Fig. 2 ). Pronotum transverse, anterior angles indistinctly protruded apicad. Antennomeres 4–10 moderately short. Protarsomeres 1–4 moderately narrow. Medial margin of protibia without peg setae; mesotibia without modifications, moderately slender, gradually slightly widened apicad. Abdominal tergite VIII and sternite VIII indistinctly rounded apically.

Comparative notes. Based on the general shape of the aedeagus with relatively wide apical portion of the median lobe and long parameres, and on the presence of wide field of the strongly sclerotized thorns in basal half of the internal sac, A. feldmanni sp.n. is most similar to A. rotundatum Shavrin & Smetana, 2018 (Sichuan: Daxue Shan, Gongga Shan) and A. tibetanum Shavrin & Smetana, 2018 (Tibet: Chola Mountains), from which it differs by the shape of more elongate apical part of the median lobe and wider apical portions of the parameres. Additionally, from A. rotundatum it differs by significantly shorter parameres. From both these species, A. feldmanni sp.n. can be distinguished by the larger and somewhat darker body, by the shape of anterior angles of the pronotum more protruded apicad in male, and by the shorter elytra. Besides that, based on internal and external structure of the aedeagus, the new species is similar to A. subelongatum Shavrin & Smetana, 2018 , from which it can be distinguished the narrower median lobe with wider apex, as well as by the longer antennomeres 4–11 and markedly narrower forebody.

Distribution. The new species is at present known only from the type locality in the Huanglong Shan range in northern Sichuan, China.

Bionomics. Specimens were collected at elevation 2611 m a.s.l. The detailed ecological data are unknown.

Etymology. Patronymic, the species is named to honor my colleague, Benedikt Feldmann of Münster, Germany

Figures

FIGURES 1–2. Habitus of Amphichroum feldmanni: 1—male, 2—female. Scale bar: 1.00 mm.

FIGURES 3–4. Aedeagus of Amphichroum feldmanni: 3—parameral view, 4—lateral view. Scale bar: 0.10 mm.