Mecyclothorax invisitatus, 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 : 253-256

Taxon classification Animalia Coleoptera Carabidae

(102) Mecyclothorax invisitatus sp. n. Figs 133C, 136B, 137B, 138 A–C, 139

Diagnosis.

Among the Haleakalā members of the Mecyclothorax ducalis group, this species is diagnosable by: 1, pronotum with lateral seta present; 2, elytra with apical margins flavous, contrasted to the rufopiceous disc; 3, pronotal disc glossy, microsculpture absent; 4, elytra narrowly subovoid, MEW/MPW = 1.52-1.62. Externally the cryptic sibling species, Mecyclothorax insolitus , differs in the last two criteria, with male aedeagal median lobe configuration offering an additional diagnostic difference between the species. Males of this species have the median lobe apex expanded into a dorsal hook, with the apex rounded ventrally (Fig. 138 A–C), whereas Mecyclothorax insolitus males have the median lobe apex expanded both dorsally and ventrally, with the apical margin straighter (Fig. 134 F–K). Setal formula 2 1 2 0. Standardized body length 4.3-5.1 mm.

Description

(n = 4). Head capsule with frontal grooves broad and deep near clypeus, a broad lateral convexity anterad eye, and low carina mesad anterior supraorbital seta; dorsal impression of neck broad, shallow, the concavity visible in dorsal view; ocular lobe protruded obtusely from gena, eyes moderately convex, ocular ratio = 1.50-1.55, ocular lobe ratio 0.80-0.84; labral anterior margin moderately, angularly emarginate 1/6 of labral length; antennae filiform, antennomeres 2-3 with sparse pelage of short setae; mentum tooth with sides acute, apex rounded. Pronotum moderately transverse, MPW/PL = 1.15-1.24, constricted basally with lateral margins briefly sinuate anterad right to obtuse hind angles, MPW/BPW = 1.53-1.62; median base slightly depressed medially relative to disc, more so laterally, ~20 punctures each side isolated in glossy surface; basal margin distinctly convex between hind angles; median longitudinal impression finely incised, crossed by indistinct transverse wrinkles; anterior transverse impression shallow, broad, smooth, incised only mesad front angle; anterior callosity slightly convex, smooth; front angles slightly projected, tightly rounded; pronotal apical width subequal to slightly broader than basal width, APW/BPW = 1.0-1.05; lateral marginal depression obsolete, narrowly beaded except slightly broader at front angle and evenly elevated from laterobasal depression to apex of projected hind angle; laterobasal depression deep, narrow, continuous with lateral depression. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process slightly convex medially but with broad upraised margin. Elytra convex, sides distinctly sloped to vertical juncture with lateral marginal depression; basal groove briefly curved to proximate, subangulate humerus at juncture with broader lateral marginal depression, MEW/HuW = 2.22-2.50; parascutellar striole with 5 punctures, striole shallow between punctures; sutural interval slightly more convex than lateral intervals basally, more upraised apically; discal striae 1-6 distinctly punctate, progressively shallower laterally, stria 7 a series of shallow punctures at midlength; sutural stria deep and smooth on elytral apex, striae 2-3 broad and very shallow there, lateral striae not visible; discal elytral intervals 2-4 moderately convex, outer intervals follow curvature of elytron; 2 dorsal elytral setae at 0.25 × and 0.51 –0.53× elytral length, setal impressions shallow, crossing ¼ of interval 3; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression narrow throughout length, edge upturned at humerus, beaded laterally to subapical sinuation; subapical sinuation shallow, symmetrical. Mesepisternum with ~14 punctures in 2-3 rows; metepisternal width to length ratio = 0.79; metepisternum/metepimeron suture distinct. Abdomen with irregular longitudinal wrinkles on ventrites 1-6, round lateral impressions on ventrites 3-6; suture between ventrites 2 and 3 effaced; male apical ventrite with 2 marginal setae and female apical ventrite with 4 equally spaced setae and median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.20; metatarsomere 4 length along outer lobe 1.3 × medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci broad, shallow, median area subcarinate. Microsculpture of vertex an obsolete transverse mesh, sculpticell breadth 2 × length; pronotal median base glossy medially, indistinct transverse sculpticells present laterally; elytral disc and apex glossy, microsculpture obsolete; metasternum with a transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufous; antennomeres 1-2 rufoflavous, 3-11 darker, rufobrunneous; pronotal disc rufous, lateral margins, base, and apex narrowly rufoflavous; proepipleuron flavous, proepisternum rufous with piceous cast; elytral disc rufopiceous, sutural interval rufobrunneous basally, rufoflavous apically, elytral margins with intervals 7-9 or 8-9 contrastedly paler, rufoflavous to flavous, apex (up to apical 0.2 × length) flavous; elytral epipleuron flavous dorsally, piceous ventrally, metepisternum rufopiceous; abdomen with all ventrites piceous mediobasally, flavous laterally, apical ventrite with apical ¾ flavous; metafemur flavous; metatibia rufoflavous with brunneous cast.

Male genitalia (n = 2). Aedeagal median lobe gracile, distance from parameral articulation to tip 3.8 × depth at midlength (Fig. 138A, C); apex hooklike with blunt dorsal projection and evenly convex tip, the ventral margin not expanded ventrally as in Mecyclothorax insolitus (Fig. 134D, F, G, K); median lobe apically curved rightward at approximately 60° angle in ventral view (Fig. 138C, E, J), tip narrowly rounded in this view; internal sac with heavily spiculated dorsal ostial microtrichial patch at base of sac, and ventral ostial microtrichial patch at midlength (Fig. 138C, F, H); flagellar plate large, length 0.51 × parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar, narrow with rounded apex, length 1.14 mm, apical width 0.40 mm, minimal width 0.30 mm (Fig. 136B); bursal walls more translucent basally, more thickly wrinkled apically; gonocoxite 1 with 3 short apical fringe setae, a curved seta at medioapical angle and 4-5 setae on medial surface (Fig. 137B); gonocoxite 2 short and broad basally, triangular with lateral margin evenly expanded to base, 2 small lateral ensiform setae, apical nematiform setae on medioventral surface at 0.80 × gonocoxite length (short, broad apex may be due to wear).

Holotype.

Male (NMNH) labeled: HI: Maui Haleakala / Waikamoi N.C.P. Maile / Rd. 2-V-1998 lot05 / 1435 m el. pyrethrum fog / mossy log D.A. Polhemus // 1 // HOLOTYPE / Mecyclothorax / invisitatus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes.

HI: Maui: Koolau For. Res., Koolau Flume Rd., wet forest, yellow pan trap, 1280 m el., vi-viii-2006, Leblanc (CUIC, 2; UHIM, 2), Kula Pipeline Rd., pyrethrin fog log, 1305 m el., 18-v-2003 lot 09, Polhemus (NMNH, 1), Makawao Flume Rd., ecotone forest, yellow pan trap, 1293 m el., vi-viii-2006, Leblanc (UHIM, 2); Waikamoi N.C.P., Maile Rd., pyrethrin fog mossy log, 1435 m el., 02-v-1998 lot 05, Polhemus (NMNH, 1), Maile Rd., under logs on ground, 1494 m el., 16-v-2003 lot 06, Liebherr (CUIC, 1).

Etymology.

This close relative of Mecyclothorax insolitus is given the name Mecyclothorax invisitatus to signify the two species’ affinity. The adjective insolitus is translated as unusual, uncommon, or strange ( Brown 1956), whereas invisitatus can be translated as strange, new, uncommon ( Brown 1956). Thus the new species name proposed here owes its origin to David Sharp’s (1903) use of insolitus for the former species.

Distribution and habitat.

Mecyclothorax invisitatus is restricted to forests in the Waikamoi area from 1280-1500 m elevation (Fig. 139). All collections to date have been in association with ground-level microhabitats; under or in downed logs, or in yellow-pan traps.