Holcoderus formosanus Jedlicka

Hunting, Wesley & Yang, Man-Miao, 2019, A taxonomic review of the pericaline ground-beetles in Taiwan, with descriptions of new species (Coleoptera, Carabidae, Lebiini), ZooKeys 816, pp. 1-164 : 106-110

Holcoderus formosanus Jedlicka Figs 79, 80 A–D, 81, 94A

Holcoderus formosanus Jedlička, 1940: 14; Habu 1979 b: 51; Lorenz 2005: 455.

Types and other material examined.

Holotype (male) labeled "Hakure/9. IV. 1929/Col. T. Shiraki"; “TYPUS” [rectangle, red, black border]; " Holcoderus / formosanus /sp.n./DET. ING. JEDLICKA"; " NCHU# 100117". Four specimens of H. formosanus : three males and one female. For further details see EH Strickland Virtual Entomology Museum Database.

Type locality.

Taiwan. “Horisha” = Puli

Diagnosis.

Specimens of this species are easily distinguished from other Taiwanese pericalines by a combination of the small size, pronotum with narrow bead along margin lateral margin and the metallic blue to green dorsal coloration.

Redescription.

OBL 8.17 - 8.58 mm. Length (n = four males, one female): head 0.88 - 0.92, pronotum 1.44 - 1.62, elytra 4.42 - 4.75, metepisternum 1.14 - 1.20 mm; width: head 1.72 - 1.88, pronotum 1.76 - 1.96, elytra 2.58 - 2.92, metepisternum 0.52 - 0.54 mm.

Body proportions. HW/HL 1.95 - 2.09; PWM/PL 1.19 - 1.23; EL/EW 1.60 - 1.71; ML/MW 2.19 - 2.30.

Color. Fig. 79. Varies depending on lighting and angle of observation. Dorsum of head and clypeus metallic blue to violaceous, dark, labrum metallic green to cupreous, antennae and palpi brunneo-piceous; disc of pronotum metallic blue to violaceous, some specimens with basal fovea and lateral margins metallic green; elytral disc metallic blue to metallic green, some specimens slightly violaceous; ventral surface piceous; legs brunneo-piceous to piceous.

Microsculpture. Head with very shallow microsculpture, almost isodiametric to isodiametric; pronotum with very shallow microsculpture, transverse; disc of elytra with transverse microsculpture, some places near suture approaching isodiametric, easily visible at 50 ×; ventral surface with transverse microsculpture.

Macrosculpture and pilosity. Dorsum of head and pronotum with scattered setigerous punctures, punctures easily visible but setae hardly so at 50 ×, pronotum faintly rugulose laterally; elytra with shallow lateral depression at basal 1/5, interval 7 carinate in basal half, other intervals moderately flat, each interval with a single row of setigerous puncture centrally; ventral surface with randomly scattered punctures, some bearing setae.

Fixed setae. Two pairs of supraorbital setae; clypeus with two long, lateral setae; labrum with six setae along apical margin; one pair of suborbital setae; pronotum with two pairs of setae, one at base of lateral margin and one on lateral margin at pronotum max width; 15-16 lateral (umbilical) setae in interval 9; elytra with interval 3 with three setae, first on outside of interval in basal 1/5, second on outside of interval at mid-length, third on inside of interval near apex; ventral surface with two setae on each of abdominal sterna III to VI; four setae along apical margin of sternum VII; legs with ventral surface of fore-femur with dense brush of long setae, less so in females.

Luster. Dorsal surface glossy; ventral surface moderately glossy to glossy.

Head. Mandibles curved at apex; labrum bilobed, shallowly emarginate; mentum with tooth; eyes moderately convex; palpi cylindrical and elongate.

Pronotum. Anterior transverse impression shallow; posterior transverse impression moderately deep, median longitudinal impression deep; lateral margins narrow, posterio-lateral margins slightly sinuate, almost right-angled.

Elytra. Elytra relatively long and narrow, hind angles truncate.

Hind wings. Macropterous.

Legs. Tarsal claws denticulate, three to four denticles per claw, claws relatively short; males with adhesive vestiture ventrally, two rows squamo-setae on tarsomeres 1-3 of fore-leg, males with several shallow notches apically on ventral side of mid-tibia.

Male genitalia. Fig. 80 A–D. Length 1.28 - 1.44 mm. Ostium catopic. Phallus cylindrical, distinctly curved at base, almost to right angle, apex short, broadly rounded; endophallus short, widely expanded laterally in apical portion, two long, distinctive flagellum (ef) near apex of lateral expansion

Female genitalia. Fig. 94A. Width 1.16 mm. Gonocoxite 2 (gc2) wide from base to midlength, beyond midlength, narrowing, somewhat spatulate; two lateral ensiform setae in close proximity (les), one dorsal ensiform seta (des). Sensory furrow, furrow pegs and associated nematiform setae not observed. One spermatheca present (sp1), somewhat elongate, cylindrical and pointed at apex, distinctive diverticulum (div) at spermatheca base; one spermathecal accessory gland (sg), round, associated spermathecal gland duct (sgd) with attachment site near apex of spermatheca.

Habitat, habits, and seasonal occurrence.

From the few specimens examined, it appears that this is a low-land species. It is possible that this species is diurnal because in three years of night collecting, we have not encountered it. Specimens have been collected in April and May. All known specimens were hand collected.

Geographical distribution.

Holcoderus formosanus is known only from Taiwan. See Figure 81.