Mecyclothorax semistriatus, Liebherr, James K., 2015

Liebherr, James K., 2015, The Mecyclothorax beetles (Coleoptera, Carabidae, Moriomorphini) of Haleakala-, Maui: Keystone of a hyperdiverse Hawaiian radiation, ZooKeys 544, pp. 1-407 : 155-157

Taxon classification Animalia Coleoptera Carabidae

(063) Mecyclothorax semistriatus sp. n. Figs 81B, 82 A–B, 83A, 84A, 85

Diagnosis.

This (Fig. 81B) and the following Mecyclothorax refulgens (Fig. 81C) synapomorphously exhibit pale, flavous elytral margins that contrast with the piceous elytral disc. Beetles of this species have broader bodies, with the pronotum more transverse, MPW/PL = 1.21-1.32, and the elytra more broadly ellipsoid, the greatest width just behind midlength. Cuticular microsculpture is less developed in this species, the vertex covered with shallow isodiametric sculpticells in transverse rows, the elytral disc covered with a shallow, elongate transverse mesh, sculpticell breadth 2 –3× length. Also, beetles of this species are larger than those of Mecyclothorax refulgens ; standardized body length 5.1-5.4 mm. Setal formula 2 2 2 2.

Description

(n = 5). Head capsule with frontal grooves broad and moderately deep near clypeus, bordered laterally by broad carina to supraorbital seta; dorsal surface of neck flat to convex; eyes convex, of moderate size, ocular ratio = 1.39-1.47, ocular lobe ratio = 0.76-0.80; labral anterior margin broadly, shallowly emarginate; antennae filiform, antennomere 3 sparsely setose; mentum tooth with sides acute, apex tightly rounded. Pronotum cordate, lateral margins distinctly sinuate basally, hind angles acute, projected, MPW/BPW = 1.53-1.61; median base depressed relative to disc, with ~12 rounded punctures and sinuous depressions each side; basal margin slightly convex medially; median longitudinal impression fine, shallow, anterior transverse impression moderately deep, narrow, longitudinal wrinkles fore and aft; anterior callosity slightly convex, with indistinct longitudinal wrinkles; front angles slightly projected, tightly rounded; pronotal apex variably as broad as base, APW/BPW = 0.98-1.11; lateral marginal depression narrow throughout, margin upraised to beaded; laterobasal depression narrow, with low oblique ridge terminated at hind angle. Proepisternum with 6 punctures along hind marginal groove; prosternal process medially concave, margin smoothly upraised. Elytra moderately convex, disc narrowly flattened medially; basal groove recurved at tightly rounded humeral angle, MEW/HuW = 2.0-2.22; parascutellar seta present; parascutellar striole with 4 punctures, shallow between punctures; sutural interval of same convexity as intervals 2-3; sutural and 2nd striae of subequal depth from base to apex; discal striae 1-3 shallow with small but evident punctures, lateral striae 4-6 shallower, traceable as isolated serial punctures, stria 7 obsolete except at elytral apex where it is broad and shallow; 8th interval as convex as fused apical portion of striae 5 + 7; 2 dorsal elytral setae at 0.23 –0.27× and 0.57 –0.69× elytral width, setal impressions shallow, spanning ½ width of interval 3; apical and subapical setae present; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression moderately broad, lined with sculpticells, margin upturned; subapical sinuation shallow, nearly obsolete. Mesepisternum with ~9 punctures in 2-3 rows; metepisternal width to length ratio = 0.78; metepisternum/metepimeron suture distinct. Abdomen with shallow indistinct lateral wrinkles on ventrites 1-3; suture between ventrites 2 and 3 complete; apical male ventrite with 2 marginal setae and apical female ventrite with 4 equally spaced setae plus median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.18; metatarsomere 4 length along outer lobe 1.4 × medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci broad, shallow. Microsculpture of pronotal median base of distinct isodiametric sculpticells in transverse rows; elytral apex with distinct transverse mesh; metasternum with shiny transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomeres 1-4 flavous, 5-11 rufobrunneous; pronotal disc rufobrunneous, margins narrowly rufoflavous; proepipleuron rufoflavous, proepisternum rufobrunneous; elytral disc reflective rufopiceous, sutural interval rufous basally, flavous apically; elytral margins broadly paler, with intervals 7-9 or 8-9 rufoflavous near interval 6 to flavous laterally, apex broadly flavous apicad subapical sinuation; elytral epipleuron flavous with rufous cast, metepisternum rufobrunneous with piceous cast; abdomen with ventrites 1-2 piceous, 3-5 rufoflavous, 6 broadly flavous; metafemur flavous, metatibia rufoflavous.

Male genitalia (n = 1). Aedeagal median lobe robust, distance from parameral articulation to tip 3.2 × depth at midlength (Fig. 82A); apex narrowed distad ostial opening, tip expanded dorsally, knoblike; median lobe distinctly curved rightward near apex in ventral view (Fig. 82B), left margin indented before parallel-sided, bluntly rounded tip; internal sac with small dorsal ostial microtrichial patch (left patch in Fig. 82B) and larger ventral ostial patch; flagellar plate of moderate size, length 0.38 × parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar with rounded apex, length 0.82 mm, breadth 0.37 mm (Fig. 83A); bursal walls translucent, smooth with a few wrinkles; gonocoxite 1 with 4 apical fringe setae, the middle two setae larger, 1 small seta basad apicomedial angle, 5-7 smaller setae on medial surface (Fig. 84A); gonocoxite 2 broadly falcate, base broadly extended laterally, 2 stout, apically narrowed lateral ensiform setae, apical nematiform setae on medial surface at 0.80 × gonocoxite length.

Holotype.

Male (CAS) labeled: U.S.A. Hawaii: Maui, / Haleakala nw. slope / Waikamoi Reserve / Transect 3, 1950 m, / 7 May 1991, Stop #91-10B / D.H. Kavanaugh collector // D.H. Kavanaugh / collection // 2 // HOLOTYPE / Mecyclothorax / semistriatus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes.

Same data as holotype (CAS, 2; CUIC, 2).

Etymology.

The adjectival species epithet semistriatus refers to the medially striate and laterally smooth elytra.

Distribution and habitat.

The type series of Mecyclothorax semistriatus was found in moss adhering to tall mastlike ‘ōhi‘a trees in the upper Honomanu drainage, 1950 m elevation (Fig. 85). The ‘Ōhi‘a Mesic Forest is quite open here, with the moss layers rather thin, though they were moist at the time of collecting.