Geodromicus philydroides 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 : 592-594

Geodromicus philydroides Shavrin & Smetana , sp. n.

( Figs. 1 , 3−5 , 12−13 , 17 )

Type material examined. Holotype ♂: ‘ TAIWAN Nantou | Hsien, Shanlinchi | 1650m, 19.V.1991 | A. Smetana [T87]’ <rectangular label, printed>, ‘ HOLOTYPE | Geodromicus | philydroides sp.n. | Shavrin A.V. & Smetana A. des. 2015’ <red rectangular label, printed> (CSm).

Paratype: 1 ♂ [The last abdominal segment of the specimen was glued under the beetle; a plastic plate with a preparation of the aedeagus in Canadian balsam was pinned under the beetle]: same data as the holotype, with additional labels: ‘ Geodromicus 1 [handwritten] | A. Smetana det. 2015’ <rectangular label, printed>, ‘ PARATYPE | Geodromicus | philydroides sp.n. | Shavrin A.V. & Smetana A. des. 2015’ <red rectangular label, printed> (CSh).

Description. Measurements (n=2): WH: 0.87; LH: 0.70–0.72; LA (holotype): 2.10; LE: 0.25; LT: 0.22−0.24; LPM × WPM (holotype): III: 0.15 × 0.08, IV: 0.12 × 0.05; LP: 0.80; WPMax: 0.93–0.97; WPMin: 0.67–0.71; LEl: 1.42; WE: 1.37–1.45; WA: 1.25−1.35; LAed: 0.70; TL: 4.50 (holotype)–4.75.

Forebody and antennomeres 1–3 black; abdomen dark brown; legs and antennomeres 4–11 brown; mouthparts, anterior parts of femora and tarsi red brown; apical tarsomeres yellow brown; ocelli yellow. Punctation of head dense, deep and coarse, interspaces between punctures on infraorbital ridge as broad as diameter of nearest puncture, interocellar impression with distinctly smaller punctation; punctation of pronotum deep, slightly sparser than that on head, with impunctate area between longitudinal and basal depressions; scutellum without punctures; punctation of elytra sparse, moderately smaller than that on pronotum; abdomen with small and regular punctures. Body very glossy; head with coarse cellular microsculpture except for small area around each ocellus, clypeus with gentle microsculpture; first third of pronotum with microsculpture same as that on head, longitudinal wide depression with dense and coarse cellular microsculpture; basal half of scutellum with distinct isodiametric microsculpture; elytra without microsculpture; abdomen with dense distinct isodiametric microsculpture. Habitus as in Fig. 1 .

Head large and transverse, 1.2 times as broad as long, with very deep moderately narrow triangular interocellar impression and with convex posterior part of infraorbital ridges, with moderately wide and arcuate postocular parts. Eyes medium-sized, convex, somewhat longer than slightly convex temples. Ocelli large, distance between ocelli subequal to distance between ocellus and posterior margin of eye. Maxillary palp segment 3 1.25 times longer than apical (4th) segment. Antennae reaching half length of elytra when reclined; antennomeres with lengths × widths: 1: 0.27 × 0.10; 2: 0.20 × 0.07; 3: 0.22 × 0.07; 4–6: 0.16 × 0.07; 7–10: 0.17 × 0.08; 11: 0.25 × 0.08.

Pronotum wide and convex, 1.1−1.2 times as broad as long, slightly wider than head; anterior margin of pronotum somewhat straight; hind angles about 90º; longitudinal depression very wide and deep (holotype with pair of small weakly defined depressions in median part of pronotum); basal part of pronotum with small, moderately deep transverse depression

Elytra about as wide as long, 1.7 times as long as pronotum; anterior half of each elytral disc distinctly diagonally depressed; hind margins of elytra straight.

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

Male. Apical margins of abdominal tergite VIII ( Fig. 3 ) and abdominal sternite VIII ( Fig. 4 ) with wide emargination. Male genital segment as in Fig. 5 . Aedeagus ( Figs. 12, 13 ) with long and moderately wide lancetshaped median lobe widened to apical third and from there gradually narrowed towards small rounded apex; parameres long, with slightly curved, wide apical lobes, slightly exceeding apex of median lobe, with four setae, placed in pairs on lateral sides of setiferous surface; endophallus with two long parallel structures along median lobe, with visibly sclerotized area composed of spine-like elements in basal part, with short, moderately wide, curved (in lateral view) flagellum, placed in basal bulb. Aedeagus in lateral aspect as in Fig. 13 .

Female unknown.

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 with unique shape of flagellum, it is similar to G. taiwanensis sp. n. (for the differences between these two species see the key below). By the coloration of the body, the longer temples, and the general shape of the median lobe of the aedeagus, it is also similar to Taiwanese G. formosanus , from which it differs by the smaller and significantly narrower body, the shorter antennae, and the morphology of the aedeagus: parameres of G. philydroides sp. n. are longer, slightly exceeding apex of the median lobe, which is narrower.

Etymology. The specific epithet “ philydroides ” refers to the similarity of the wide and deep longitudinal depression on the pronotum with that of the species of Philydrodes Bernhauer, 1929 , distributed in Japan. Distribution. The described species was collected in Central Taiwan, Nantou Hsien ( Fig. 17 ). Bionomics. Specimens were taken in original broadleaved forest by sifting accumulated wet debris and leaf litter along a creek.

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 12 – 13. Aedeagus of Geodromicus philydroides sp. n.: 12 — parameral view, 13 — 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.