Geodromicus namucuoicus Cheng & Peng, 2020

Cheng, Zhi-Fei, Shavrin, Alexey V. & Peng, Zhong, 2020, New species and records of Geodromicus Redtenbacher, 1857 from China (Coleoptera: Staphylinidae: Omaliinae: Anthophagini), Zootaxa 4789 (1), pp. 132-170 : 148-149

Geodromicus namucuoicus Cheng & Peng sp. n.

( Figs. 57 , 59 –63, 113)

Type material examined: Holotype ♂: ‘ China: Xizang A. R., Lasa City, | Dangxiong County, | near Namucuo Lake, | 4,718 m a.s.l., 7.VIII.2004, | Li-Zhen Li leg.’ <white rectangular label, printed>, ‘ HOLOTYPE | Geodromicus | namucuoicus sp. n. | Cheng & Peng des. 2019’ <red rectangular label, printed> ( SNUC).

Paratypes (3 ♂♂, 2 ♀♀): 3 ♂♂ [two specimens dissected], 2 ♀♀: same data as the holotype, ‘ PARATYPE | Geodromicus | namucuoicus sp. n. | Cheng & Peng des. 2019’ <red rectangular label, printed> ( SNUC).

Description. Measurements (min-max; n=6): HW: 0.95–1.00; HL: 0.78–0.83; OL: 0.23–0.27; LT: 0.12–0.15; AL: 2.78–3.13; PL: 0.89–0.95; PWmax: 1.28–1.33; PWmin: 1.17–1.22; ESL: 1.56–1.83; EW: 1.72–2.00; MTbL (holotype): 1.31; MTrL (holotype): 0.56 (MTrL 1–4: 0.31; MTrL 5: 0.25); AW: 1.85–2.10; AedL: 0.95–1.37; BL: 5.34–5.50.

Body reddish-brown to brown, with paler, yellow-brown to reddish-brown posterolateral portions of pronotum, elytra and apical abdominal tergites; legs reddish; mouthparts, antennae, and tarsi yellow. Body glossy, without microsculpture on elytra and scutellum; head with fine microsculpture; neck with distinct large isodiametric sculpture; pronotum with distinct isodiametric microreticulation; abdominal tergites with dense and distinct isodiametric microsculpture. Habitus as in Fig. 57 .

Head 1.2 times as wide as long, slightly convex between anteromedian depression and in portions between ocelli and eyes; frontal portion with relatively deep and wide anteromedian depression, distinctly narrowed basad to level of anterior margins of eyes; interocellar depression wide and moderately deep, slightly narrowing basad, separated from infraorbital ridges by fine and long convergent grooves in front of ocelli; temples relatively long, convex, slightly less than half as long as eyes. Eyes moderately large, strongly convex. Ocelli small, distance between ocelli about 1.2 times as long as distance between ocellus and posterior margin of eye. Punctation irregular and fine, indistinct in apical portion, more distinct and denser on infraorbital ridges. Neck with or without indistinct and irregular very fine punctures. Preapical segment of maxillary palp about as long as preceding segment, markedly widened apicad; apical palpomere about 0.8 times as long as preapical segment, widest in basal portion, gradually narrowing apically. Antennae moderately long, exceeding apical third of elytra when reclined; lengths × widths of antennomeres (holotype): 1: 0.27 × 0.12; 2: 0.17 × 0.10; 3: 0.22 × 0.10; 4: 0.21 × 0.10; 5: 0.23 × 0.10; 6–7: 0.26 × 0.11; 8–9: 0.27 × 0.11; 10: 0.25 × 0.11; 11: 0.37 × 0.11.

Pronotum slightly convex, transverse, 1.4 times as wide as long, 1.3 times as wide as head, widest in anterior third, more narrowed posteriad than anteriad, with anterior angles rounded and indistinctly protruded; narrow basal part of pronotum with straight lateral margins and with obtuse posterior angles; anterior and posterior margins straight; median portion without impressions. Punctation dense, markedly larger, deeper, and coarser than that in head, finer and sparser in middle.

Scutellum very large, with several irregular, fine punctures.

Elytra slightly convex, 1.1 times as wide as long, 1.7–1.9 times as long as pronotum, slightly widened posteriad towards broadly rounded posterior portions; lateral margins rather broadly flattened. Punctation dense, slightly deeper than that of pronotum, with interspaces between punctures about as broad as combined diameters of two nearest punctures, punctures markedly finer in basal and prescutellar portions.

Metatarsi distinctly more than half as long as metatibia; apical metatarsomere slightly shorter than preceding four metatarsomeres.

Abdomen slightly wider than elytra, convex, with two distinct transverse tomentose spots in the middle of abdominal tergite IV and with two indistinct, small, round tomentose spots in the middle of tergite V. Punctation regular, fine and dense.

Male. Protarsomeres 1–4 wide. Apical margin of abdominal tergite VIII ( Fig. 59 ) somewhat straight. Apical margin of abdominal sternite VIII ( Fig. 60 ) slightly sinuate. Aedeagus (Figs. 61, 63) with moderately large basal portion, a relatively wide and long median lobe; median lobe gradually narrowed towards the slightly elongate apex; parameres narrow, curved in apical portion, distinctly extending beyond apex of median lobe, with three apical and one latero-apical moderately short setae; internal sac weakly sclerotized, with moderately narrow and very long flagellum coiled in basal part of aedeagus. Lateral aspect of aedeagus as in Fig. 62.

Female. Protarsomeres 1–4 moderately narrow. Apical margins of abdominal tergite VIII and sternite VIII straight or slightly rounded.

Comparative notes. Based on the general shapes of the body and the pronotum, as well as on the external and internal structure of the aedeagus, G. namucuoicus sp. n. belongs to the crassipalpis group (Shavrin 2019). It differs from all the species of this group by the paler coloration, the shape of anterior angles of the pronotum (indistinctly protruded anteriad), shorter elytra, the absence of a median impressions on the pronotum, and a very narrow apex of the median lobe.

Distribution. The species is known only from the type locality near Namucuo Lake in Xizang Autonomous Region, China ( Fig. 113 ).

Bionomics. The specimens were collected at an elevation of 4718 m a.s.l. by sifting mixed leaf litter near Namucuo Lake.

Etymology. The specific epithet is the Latinized adjective derived from Namucuo Lake.

Figures

FIGURE 113. Distribution of 21 species of Geodromicus in China: 1–G. abdominalis, 2–G. amplissimus, 3–G. aokii, 4–G. beibienkoi, 5–G. chinensis, 6–G. cupreostigma, 7–G. formosanus, 8–G. frigidus, 9–G. hammondi, 10–G. lestevoides, 11–G. magnus sp. n., 12–G. namucuoicus sp. n., 13–G. ohkurai, 14–G. philydroides, 15–G. shii sp. n., 16–G. sibiricus, 17–G. sinuatocollis, 18–G. sinuatus, 19–G. smetanai, 20–G. subquadratus sp. n., 21–G. taiwanensis.

FIGURES 57–58. Habitus of species of Geodromicus: 57–G. namucuoicus sp. n. (holotype), 58–G. paramerus (Ningxia). Scale bar: 2.0 mm.

FIGURES 59–60. Male of Geodromicus namucuoicus sp. n. (paratype): 59–abdominal tergite VIII, 60–abdominal sternite VIII, 61–aedeagus, dorsal view, 62–aedeagus, lateral view, 63–aedeagus, parameral view. Scale bar: 0.2 mm.