Mecyclothorax takumiae, 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 : 124-126

Taxon classification Animalia Coleoptera Carabidae

(048) Mecyclothorax takumiae sp. n. Figs 65B, 67

Diagnosis.

Within the Mecyclothorax ovipennis group, this species (Fig. 65B) forms part of a triplet of species also including Mecyclothorax apicalis (Fig. 65C) and Mecyclothorax parapicalis (Fig. 65D) that are collectively diagnosed by glabrous, obtuse pronotal hind angles, shallow impunctate discal elytral striae, and concolorous elytral disc and margins. Of these, Mecyclothorax takumiae is characterized by the smallest body size, standardized body length 3.6 mm, and least developed microsculpture. The pronotal disc and median base are glossy with obsolete transverse-mesh microsculpture and parallel lines over portions of the cuticle, whereas the elytral disc has a shallow mesh of isodiametric and transverse sculpticells, breadth 2 –3× length. Both Mecyclothorax apicalis and Mecyclothorax parapicalis have well-developed sculpticells covering those areas. Setal formula 2 1 2(1) 0; the right elytron has both dorsal elytral setae, whereas the left has only a seta at the anterior position of the right elytron. As the bisetose condition is shared with Mecyclothorax apicalis and Mecyclothorax parapicalis , the unisetose elytron is considered a variant.

Description

(n = 1). Head capsule with frontal grooves broad near clypeus, lateral carina to anterior supraorbital seta; dorsal surface of neck flat; eyes moderately developed, ocular ratio = 1.45, ocular lobe ratio = 0.80; labral anterior margin medially emarginate, medially excavated 1/6 of length; antennae filiform, antennomeres 2-3 with only 1 or 2 short setae on shafts; mentum tooth with sides acute, apex rounded. Pronotum slightly transverse, MPW/PL = 1.21, moderately constricted basally, MPW/BPW = 1.53; hind angle obtuse, margin behind rounded; median base markedly depressed versus disc, ~9 punctures each side, surface glossy between; basal margin convexly expanded between laterobasal depressions; median longitudinal impression shallow, finely incised, crossed by fine transverse wrinkles; anterior transverse impression narrow, shallowly incised laterally, obsolete medially; anterior callosity slightly convex, smooth, glossy; front angles not to slightly projected, tightly rounded; pronotal apical and basal width equal, APW/BPW = 1.0; lateral marginal depression narrow through apical 1/3 of length, edge upturned, widened in basal 1/3; laterobasal depression narrow, surface irregular, continuous with lateral depression. Proepisternum with 5 minute punctures along hind margin; prosternal process with narrow median impression, lateral margins broadly beaded between coxae. Elytra subquadrate, disc flat, sides distinctly sloped; basal groove evenly recurved to subangulate (left) to tightly rounded (right) humerus, MEW/HuW = 2.04; parascutellar seta present; parascutellar striole with 4 punctures, shallow between punctures; sutural interval slightly more convex than lateral intervals, upraised at sutural juncture; sutural stria shallow, continuous basally, punctate on disc, smooth and deep apically; striae 2-6 progressively shallower, smooth, stria 7 obsolete; stria 1 subequal to slightly deeper than stria 2 at elytral apex; elytral interval 2 slightly convex, intervals 3-7 progressively flatter; 8th interval subcarinate laterad fused apical portion of striae 5 + 7; 2 dorsal elytral setae at 0.31 × and 0.63 × elytral length (right elytron), setal impressions moderate, spanning 2/3 of interval 3; apical and subapical setae absent; lateral elytral setae arranged in anterior series of 6 setae and posterior series of 6 setae; elytral marginal depression slightly broader at humerus, narrowed laterally, beadlike at subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~8 punctures in 1-2 rows; metepisternal width to length ratio = 0.65; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1-6; suture between ventrites 2 and 3 complete; apical female ventrite with 4 equally spaced setae plus a median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.18; metatarsomere 4 length along outer lobe 1.33 × medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, shallow, median area broad. Microsculpture of vertex a shallow transverse mesh, sculpticell breadth 2 –3× length; elytral apex with transverse mesh, sculpticell breadth 2 –3× length; metasternum with transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous with piceous cast; antennomeres 1-3 flavous, 4-11 darker, more brunneous; pronotal disc rufopiceous, lateral margins concolorous, base and apex paler, rufoflavous; proepipleuron rufoflavous, proepisternum rufobrunneous with piceous cast; elytral disc rufopiceous, sutural interval rufous in basal half, flavous in apical half; 9th elytral interval and lateral marginal depression rufous, apex of intervals 8 and 9 flavous; elytral epipleuron dorsally flavous, ventrally rufoflavous, metepisternum rufopiceous; abdomen with ventrites 1-5 and the base of 6 rufopiceous, apical 1/3 of apical ventrite 6 flavous; metafemur flavous; metatibia flavous with brunneous cast.

Female reproductive tract. The lone female holotype was not dissected.

Holotype.

Female (BPBM) labeled: HAWAII: Maui I. / Haleakala Crater / Paliku, 1950 m / 1 JUL 1998 // R. Takumi, coll. / HALE-RM / ex. pitfall trap // HOLOTYPE / Mecyclothorax / takumiae / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Etymology.

Raina Takumi Kahaloa‘a has provided numerous specimens for this revision, most often from difficult to access natural areas, and from months of the year with very few other records. Thus it is a pleasure to honor her contributions to Mecyclothorax diversity by naming this species in her honor.

Distribution and habitat.

The type specimen was collected at 1950 m elevation in a pitfall trap near Paliku Cabin. The site lies in the mesic eastern end of Haleakalā Crater, and it receives windward moisture wafting over the highest elevations of Kīpahulu Valley to the east (Fig. 67).