Geodromicus taiwanensis Shavrin & Smetana

Smetana, Aleš, 2016, New species and records of the genus Geodromicus Redtenbacher, 1857 (Coleoptera: Staphylinidae: Omaliinae) from Taiwan, Zootaxa 4066 (5), pp. 591-599 : 594-597

Geodromicus taiwanensis Shavrin & Smetana , sp. n.

( Figs. 2 , 6–11 , 14–16 , 18 )

Type material examined. Holotype ♂: ‘ TAIWAN, Kaohsiung | Hsien, Crk. 4km E | Yakou, 2600m 23.VII. | [19]93 A.Smetana [T162]’, ‘ Geodromicus 2 [handwritten] | A. Smetana det. 2015’ <rectangular label, printed>, ‘ HOLOTYPE | Geodromicus | taiwanensis sp.n. | Shavrin A.V. & Smetana A. des. 2015’ <red rectangular label, printed> (CSm).

Paratypes [Three males (two from Yakou and one from Nanhushi) were dissected: last abdominal segments of the specimens were glued under the beetles; plastic plate with the aedeagus in Canadian balsam was pinned under beetles]: 5 ♂, 14 ♀: same data as the holotype (CSm, CSh); 1 ♀: ‘ TAIWAN, Kaohsiung | Hsien, Peinantashan | trail 2450m, 2.V.1995 | A. Smetana [T170]’ (cSm); 1 ♂, 7 ♀: ‘ TAIWAN Hualien | Hsien, Taroko N.P. | Nanhushi Hut | 2220m 8.V.1990 | A. Smetana [T48]’ (cSm, cSh); 1 ♀: ‘ TAIWAN Hualien | Hsien, Taroko N. P. | Chungyantienshi | (Riv.) Waterfall | 2300m 10.V.1990 | A. Smetana [T50]’ (cSm). All paratypes with our additional label: ‘ PARATYPE | Geodromicus | taiwanensis sp.n. | Shavrin A.V. & Smetana A. des. 2015’ <red rectangular label, printed>.

Description. Measurements (n=30): WH: 0.70–0.87; LH: 0.50–0.70; LA (holotype): 2.13; LE: 0.18−0.25; LT: 0.12−0.22; LPM × WPM (holotype): III: 0.16 × 0.07, IV: 0.15 × 0.05; LP: 0.60–0.75; WPMax: 0.75–0.87; WPMin: 0.51–0.60; LEl: 1.14–1.37; WE: 1.24–1.47; WA: 1.21−1.47; LAed: 0.65; TL: 3.30–4.60 (holotype: 4.25).

Body and antennomeres reddish brown to brown; apical margins, basal third of each elytron and paratergites yellow brown to reddish brown; legs yellow brown, apical part of femora and/or entire length of tibiae brown; ocelli, basis of antennomeres 1–3 and mouthparts yellow to reddish yellow. Punctation of head dense, deep and coarse, interspaces between punctures on infraorbital ridge as broad as diameters of 1–2 nearest punctures, punctation somewhat coarser on interocellar impression; punctation of pronotum same as that on head, with impunctate oval area between longitudinal and basal depressions; scutellum without punctures; punctation of elytra deep, sparse and regular; abdomen with very small and regular punctures. Body glossy; head with distinct coarse cellular microsculpture, clypeus with smoother microsculpture; microsculpture of pronotum variable: same as that on head, especially on apical third, or more gentle, indistict or entirely reduced, impunctate area of basal third of pronotum without microsculpture, longitudinal wide depression with very dense and coarse microsculpture; scutellum with distinct isodiametric microsculpture or without it; elytra without microsculpture; abdomen with distinct fine isodiametric microsculpture. Habitus as in Fig. 2 .

Head 1.2–1.4 times as broad as long, with moderately deep triangular to rectangular interocellar impression and with convex posterior parts of infraorbital ridges, with moderately narrow postocular parts. Eyes mediumsized, markedly convex, 1.1–1.5 times as long as temples. Ocelli large, distance between ocelli slightly longer than distance between ocellus and posterior margin of eye. Maxillary palp segment 3 slightly longer than apical (4th) segment. Antennae reaching half length or posterior third of elytra when reclined; antennomeres with lengths × widths: 1: 0.27 × 0.10; 2: 0.17 × 0.07; 3: 0.18 × 0.07; 4: 0.17 × 0.07; 5−7: 0.18 × 0.07; 8−10: 0.18 × 0.08; 11: 0.26 × 0.08.

Pronotum small and convex, 1.1−1.2 times as broad as long, as broad as head or slightly wider; anterior margin of pronotum slightly rounded; posterior angles nearly rectangular; longitudinal depression moderately wide and deep, widest in apical part; basal part of pronotum with moderately deep transverse depression

Elytra somewhat wider than long, slightly depressed in basal third, 1.8−1.9 times as long as pronotum; hind margins of elytra straight or slightly truncate.

Abdomen as broad as elytra or slightly narrower, with two moderately wide wing-folding patches (tomentose spots) on abdominal tergite IV, with distinct palisade fringe on apical margin of abdominal tergite VII.

Male. Pronotum and front femora wider. Apical margin of abdominal tergite VIII straight ( Fig. 6 ). Abdominal sternite VIII ( Fig. 7 ) with wide and moderately deep apical emargination. Male genital segment as in Fig. 8 . Aedeagus ( Figs. 14, 16 ) with long and moderately narrow median lobe, gradually narrowing from middle part towards small rounded apex; parameres moderately wide, long, almost reaching apex of aedeagus, with four setae on apical part, placed in pairs laterally and apically on setiferous surface. Structure of endophallus in general similar to that of P. philydroides sp. n. Aedeagus in lateral aspect as in Fig. 15 .

Female. Pronotum and front femora narrower. Apical margins of abdominal tergite VIII ( Fig. 9 ) and abdominal sternite VIII ( Fig. 10 ) rounded. Female genital segment as in Fig. 11 .

Comparative notes. Based on the narrow body, the character of punctation and microsculpture of the body, the wide longitudinal depression on the pronotum, and the very similar shape of parameres and internal structure of the aedeagus, G. taiwanensis sp. n. is similar to G. philydroides sp. n., from which it differs by the paler coloration, narrower postocular parts of head and pronotum, shorter apical antennomere, the length of elytra, and by the shape of the median lobe of the aedeagus (for details see above and the key below).

Etymology. The specific epithet is an adjective derived from the geographical name Taiwan.

Distribution. The species is at present known from central (Hualien Hsien) and southern (Kaohsiung Hsien) Taiwan ( Fig. 18 ).

Bionomics. Specimens were taken in original mixed forest (T162, T170) and in old coniferous forest with lush undergrowth (T48) by sifting wet moss from large rocks directly in a creek (T162), by sifting wet leaf litter and various debris on two small seepages (T170) and at a large creek by sifting wet layers of fallen leaves, accumulated at bases of large rocks close to the water (T48). One specimen (T50) was collected near a large waterfall in an old mixed forest by sifting various debris, fallen leaves and moss in the spray zone of the waterfall.

Figures

FIGURES 1 – 2. Habitus of Geodromicus: 1 — G. philydroides sp. n., holotype, 2 — G. taiwanensis, sp. n., male, paratype. Scale bar: 1.0 mm.

FIGURES 3 – 11. Abdominal segments (dorsal view) of Geodromicus philydroides sp. n. (3 − 5) and G. taiwanensis, sp. n. (6 − 11): 3, 6 — male abdominal tergite VIII, 4, 7 — male abdominal sternite VIII, 5, 8 — male genital segment, 9 — female abdominal tergite VIII, 10 — female abdominal sternite VIII, 11 — female genital segment. Scale bars: 0.1 mm.

FIGURES 14 – 16. Aedeagus of Geodromicus taiwanensis sp. n.: 14, 16 — parameral view, 15 — lateral view. Scale bar: 0.1 mm.

FIGURES 17 – 18. Distribution of Geodromicus philydroides sp. n. (17) and G. taiwanensis sp. n. (18) in Taiwan.