Brachichila hypocrita Chaudoir

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 : 27-32

Brachichila hypocrita Chaudoir Figs 8B, 15B, 18 A–D, 19 A–C, 20

Brachichila Chaudoir, 1869: 123-124; Lorenz 2005: 456.

Brachychila hypocrita : Csiki, 1354: 1354; Jedlička: 361; Kirschenhofer 1994: 1011; Kirschenhofer 1996: 765; Kirschenhofer 2010: 28.

Types and other material examined.

123 specimens of B. hypocrita , 67 males and 56 females. For further details see EH Strickland Virtual Entomology Museum Database.

Type locality.

Hong Kong.

Diagnosis.

This species is readily separated from all other Taiwanese pericalines by having a combination of: a mentum with no tooth, four elytral maculae, an overall body length of more than 6mm and elytra with a single discal seta near the apex of stria 2.

Redescription.

OBL 6.3 - 8.2 mm. Length (n = 15 males, 15 females): head 0.64 - 0.78, pronotum 1.12 - 1.44, elytra 3.75 - 4.92, metepisternum 0.9 - 1.16 mm; width: head 1.24 - 1.60, pronotum 1.64 - 2.20, elytra 2.54 - 4.46, metepisternum 0.52 - 0.68 mm.

Body proportions. HW/HL 1.79 - 2.23; PWM/PL 1.46 - 1.65; EL/EW 1.28 - 1.51; ML/MW 1.53 - 2.00.

Color. Fig. 17A, B. Dorsum of head and clypeus rufous to brunneo-piceous; labrum, palpi and antennae rufous; pronotum rufo-brunneous to brunneo-piceous with margins somewhat translucent; elytra with disc rufo-brunneous to rufo-piceous, with four testaceous to rufo-testaceous maculae, two anterior and two posterior, anterior macula from outside of interval 3 to outside of interval 7, nearest to base at interval 7 but not touching base, closest to apex in interval 7 but ending in first third of basal portion of elytra, posterior macula from suture (stria 1 in some individuals) to inside of interval 5 (stria 4 in some individuals), closest to base in interval 3 but not extended past apical third of disc, nearest to apex at interval 3-4 but not touching apex, margins of elytra rufo-brunneous, translucent; ventrally with elytral epipleura rufo-brunneous to brunneous; thoracic sclerites and abdominal sterna rufo-testaceous to rufo-brunneous; legs with trochanter and femora testaceous to rufo-testaceous, tibia rufo-testaceous to brunneous.

Notes on variation.

Southern specimens are typically lighter in dorsal coloration. Male genitalia typically less sclerotized but this is somewhat variable within populations. Females similar throughout range.

Microsculpture. Dorsum of head with isodiametric mesh pattern easily visible at 50 × magnification; pronotum with disc isodiametric, meshes somewhat stretched at posteriolateral angles; elytra with shallow, transverse sculpticells faintly visible throughout; ventral surface of head, prosternum, proepipleuron, mesepisternum, and metepisternum with sculpticells forming a moderately transverse mesh.

Macrosculpture. Pronotum with disc faintly rugulose to smooth, margins punctate; striae punctate along length.

Pilosity. Dorsum of head and pronotum glabrous, ventral surface of head with some to no fine seta visible; striae with punctures each bearing a fine seta hardly visible at 50 × magnification; thoracic sclerites and abdominal sterna with scattered fine setae throughout, punctures not visible.

Fixed setae. Two pairs of supraorbital setae; clypeus with two lateral setae; labrum with six setae along apical margin; one pair of suborbital setae; ligula with six setae on apical margin between lobes; pronotum with two setae along each margin; elytra with one seta near apex of interval 2; 19 lateral (umbilical) setae in interval 9; two setae on each of abdominal sterna III to VI, two setae along apical margin of sternum VII in males, females with four setae near apical margin of sternum VII.

Luster. Head capsule and pronotum moderately dull; elytra moderately glossy to moderately dull; ventral thoracic sterna and abdominal sterna moderately dull.

Head. Fig. 8B. Apical margin somewhat emarginate, bilobed to almost rectangular; mentum without tooth; ligula distinctly bilobed (see Habu 1967); eyes moderately convex.

Pronotum. Anterior transverse impression shallow, posterior transverse impression deep; basal fovea deep and broad; median longitudinal impression shallow; disc convex, apical angles slightly emarginate, basal angles obtuse, somewhat rounded; lateral margins more explanate towards base, more so in males.

Elytra. Striae moderately impressed; elytral disc convex; lateral margin smooth, parallel along length; elytral apices truncate.

Hind wings. Macropterous.

Legs. Tarsal claws pectinate, three to four denticles per claw. Males with adhesive vestiture ventrally, two rows of squamo-setae on tarsomeres 1-3 of fore-leg; male meso-tibia with two deep notches on ventral surface, near base.

Abdominal sterna. Males with abdominal sternum VII faintly emarginate.

Male genitalia. Figs 18 A–D, 19 A–C. Length 1.60 - 1.74 mm. Ostium left pleuropic. Phallus base cylindrical, narrowing and distinctly curved medially toward apex in lateral view; expanded on both left and right side from median towards apex in ventral view, constricted again before apex; endophallus with several distinctive lobes, no sclerites.

Female genitalia. Fig. 15B. Width 0.76 - 0.96 mm. Gonocoxite 2 (gc2) long and narrow; two lateral ensiform (les) setae and one dorsal ensiform seta (des) present; sensory furrow, furrow pegs and associated nematiform setae not observed; two spermathecae; spermatheca 1 (sp1) and 2 (sp2) with ducts narrowly ribbed in appearance, ducts proximal; one spermathecal accessory gland (sg); spermathecal gland duct (sgd) attachment site on associated diverticulum (div).

Habitat, habits, and seasonal occurrence.

The known elevational range of B. hypocrita in Taiwan is from 200 to 1000 meters. Adults of this species are found in mixed primary and secondary forest of montane areas, as well as disturbed areas. They are crepuscular or nocturnal with most activity observed on tree trunks and deadwood at night. Several specimens were collected from the underside of fallen trees. Specimens have been collected all year round but are most commonly collected from May to October. They readily come to u.v. light. Other methods of collecting include flight intercept trap, malaise trap, sweep netting, hand collecting, and insecticidal fogging at night. Several individuals of B. hypocrita were fogged from Pinus morrisonicola Hayata at night.

Geographical distribution.

Brachichila hypocrita is apparently diffuse in Asia. It has been recorded in Japan from Okinawa, the Ryukus (Irimote Island). From Hong Kong, Vietnam, India, and Taiwan. For Taiwan collecting localities see Figure 20.