Mecyclothorax arboricola, Liebherr, James K., 2013

Liebherr, James K., 2013, The Mecyclothorax beetles (Coleoptera, Carabidae, Moriomorphini) of Tahiti, Society Islands, ZooKeys 322, pp. 1-170 : 93-94

75. Mecyclothorax arboricola sp. n.

Diagnosis.

These beetles are the largest in the Mecyclothorax globosus group to combine the presence of only the posterior supraorbital seta with the absence of dorsal elytral setae (Figs 37D, 39A, B); setal formula 1101, standardized body length 3.7-4.1 mm. The pronotum is more constricted basally than in the similarly setose Mecyclothorax sabulicola (Figs 39A versus B); MPW/BPW = 1.45-1.52 (n = 5). The dorsal microsculpture is also less developed: 1, frons glossy with a shallow isodiametric mesh on the neck; 2, pronotal disc with an indistinct transverse mesh visible outside areas of reflected light; and 3, discal elytral intervals covered with evident transverse lines accompanied by areas of transverse mesh, sculpticell breadth 3 –4× breadth. Head with frontal grooves narrow behind, radiating wrinkles emanating from groove onto frons, groove broad and shallow near frontoclypeal suture; eyes small, little convex, ocular ratio 1.38-1.43, ocular lobe meeting gena at broad shallow groove, lobe very obtusely protruded from gena, ocular lobe ratio 0.79-0.86; antennae moderately elongate, submoniliform, antennomere 8 length 1.75 × maximal breadth. Pronotum moderately transverse, MPW/PL = 1.18-1.22, cordate, lateral margins convergent before acute, projected hind angles; median base depressed relative to convex disc, smoother medially with 9-10 punctures laterally each side; anterior transverse impression broad, shallow, smooth, with at most three indistinct longitudinal wrinkles each side near middle, anterior callosity smooth, slightly convex; front angles rounded, slightly protruded; lateral marginal depression narrow, edge beaded, slightly wider inside front angle; laterobasal depression deep, surface rugose to irregularly punctate, margined laterally and basally by raised margin. Elytra ovate, MEW/HuW = 2.08-2.20, humeri angulate laterad evenly curved basal groove; disc convexly domed above depressed scutellum, sides sloped to near vertical juncture with lateral marginal depressions, sutural intervals of each elytron raised as a broad callous joined at the elevated suture; elytral striae 1-7 smooth, continuous, minute punctures at depth of stria on disc the only indication of punctation, striae 1-6 continuous and deep to basal groove, striae 1+2 fused for short distance from laterad parascutellar seta to basal groove; interval 8 convex laterally, upraised slightly laterad stria 7 apicad fused terminus of striae 3 + 4; lateral elytral setae 7 + (5-6). Coloration of head rufobrunneous, clypeus and labrum rufous; antennomere 1 flavous, 2-3 rufoflavous; 4-11 rufobrunneous; pronotal disc dark rufobrunneous, the anterior callosity and lateral margins narrowly, and median base more broadly, rufous; elytral disc rufobrunneous with silvery metallic reflection, the apex concolorous with disc, upraised sutural interval rufous, lateral marginal depressions narrowly rufoflavous, palest apically; femora and tibiae rufoflavous.

Male genitalia. Aedeagal median lobe gracile, shaft moderately narrow and slightly curved (Fig. 40F); apex asymmetrically expanded with larger ventral expansion and slight dorsal expansion, the apical face oblique; ostial canal short, terminated near dorsal margin.

Female reproductive tract. Bursa copulatrix basally as broad as vagina, apically narrowed and parallel sided when compressed under microslide cover slip (Fig. 7A); bursal surface membranous, capable of extensive expansion based on wrinkles across surface of prepared dissection; basal gonocoxite 1 narrow, elongate, with 3 small apical fringe setae and a fourth smaller seta near medioapical angle, ~6 small setae along mesal margin (Fig. 9F); apical gonocoxite 2 narrow with elongate laterobasal expansion, apex acuminate; two narrow lateral ensiform setae and one dorsal ensiform setae, plus an apical sensory furrow with two apical nematiform setae and two furrow pegs.

Holotype male (MNHN) labeled: French Polynesia: Tahiti Nui / Mt. Marau road el. 1275 m / 10-IX-2006 lot 02 / 17°36.433'S, 149°32.339'W / pyr. fog horiz. Weinmannia / trunks + veg. J.K. Liebherr // HOLOTYPE / Mecyclothorax / arboricola / J.K. Liebherr 2013 (black-bordered red label).

Allotype female (MNHN) labeled as holotype.

Paratypes: labeled as the holotype (CUIC, 2); Mt. Marau, 1280 m el., 6-xi-1999, Polhemus, pyr. fog Weinmannia forest (CUIC, 1; NMNH, 2); Mt. Marau, 1185 m el., 17°36.440'S, 149°32.877'W, 4-ix-2006 lot 02, Liebherr, pyr. fog tree fern fronds/Weinmannia (CUIC, 1).

Etymology.

The species epithet arboricola, tree loving, is of parallel derivation to that of the anatomically similar species Mecyclothorax sabulicola ; i.e., the sand-loving Mecyclothorax .

Distribution and habitat.

This species is known to occupy Weinmannia forest habitats from 1185-1280 m elevation on Mont Marau.