Mecyclothorax montanus, 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 : 36-40

Taxon classification Animalia Coleoptera Carabidae

(010) Mecyclothorax montanus sp. n. Figs 17D, 18D, 20C, 21, 22 A–B

Diagnosis.

The combination of quadrisetose pronotum, both lateral and basal setae present, subparallel to subovoid elytra, the lateral margins nearly straight along the anterior lateral setal series, and moderate body size, standardized body length, 3.4-3.8 mm, will diagnose this species. The pronotal and elytral margins are slightly paler than their respective discs (Fig. 20C), but not to the degree as in the paler-margined species treated above (Figs 15, 20A). This is also the only Haleakalā species of the group to exhibit both subapical and apical elytral setae; setal formula 2 2 2 2. Nevertheless, beetles of this species lack the parascutellar seta, and exhibit a reduced lateral elytral setal series, with base numbers of six anterior setae and five posterior setae.

Description

(n = 5). Head capsule with frontal grooves broad near clypeus, a lateral carina to anterior supraorbital seta; dorsal impression of neck flat to slightly concave; ocular lobe protruded, eyes small, ocular ratio = 1.36-1.38, ocular lobe ratio = 0.66-0.71; labral anterior margin broadly, shallowly emarginate; antennae submoniliform, antennomeres 2-3 sparsely setose; mentum tooth with sides acute, apex rounded. Pronotum quadrisetose, both lateral and basal setae present; MPW/BPW = 1.38-1.49; hind angle obtuse due to rounded margin behind; lateral margin parallel just anterad angle, then divergent; median base depressed relative to disc, a few large punctures and wrinkles present; basal margin broadly, slightly convex between laterobasal depressions; median longitudinal impression narrowly, shallowly incised, continuous to basal margin, adjoined by curved wrinkles emanating onto disc; anterior transverse impression deep, narrow, finely incised, crossed by fine longitudinal wrinkles; anterior callosity elevated, flat, crossed by fine wrinkles; front angles slightly projected, tightly rounded; APW/BPW = 0.94-1.03; lateral marginal depression narrow, edge upturned to beadlike at front, broader, less elevated to base; laterobasal depression surface impunctate with transverse wrinkles, continuous with lateral depression. Proepisternum with ~5 minute punctures along hind marginal groove; prosternal process medially depressed, sides broadly upraised. Elytra subparallel to subovoid, disc moderately convex, sides more so; basal groove evenly recurved to tightly rounded humeral angle; MEW/HuW = 1.80-2.00; parascutellar seta absent; parascutellar striole smooth, sinuous; sutural interval more convex than lateral intervals, sutural juncture upraised; sutural and 2nd striae of subequal depth from base to apex; discal striae 1-7 with small punctures that cause strial irregularities; 7th and 8th interval of similar convexity mesad subapical sinuation; 2 dorsal elytral setae at 0.28 –0.35× and 0.59 × elytral length; setal impressions moderate, spanning 2/3 of interval 3; apical and subapical setae present; lateral elytral setae arranged in anterior series of 6 setae, and posterior series of 5 setae (rarely 4 or 6 setae); elytral marginal depression narrow from humerus to midlength, gradually narrowed to bead at subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~7 punctures in 2-3 rows; metepisternal width to length ratio = 0.80; metepisternum/metepimeron suture distinct; metathoracic flight wing length to width ratio = 2.2, remnant R and M veins present, wing tip extended 2/3 distance to hind margin of metanotum. Abdomen with irregular lateral wrinkles on ventrites 1-5; suture between ventrites 2 and 3 complete; apical male ventrite with 2 marginal setae, apical female ventrite with 4 equally spaced marginal setae and median trapezoid of 4-5 short setae (the 5th seta, when present, shorter). Legs-metatarsomere 1/metatibial length ratio = 0.19; metatarsomere 4 length along outer lobe 1.28 × medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, lateral, median area broad. Microsculpture of vertex very shallow, transverse, sculpticell breadth 2 × length; pronotal disc with shallow transverse mesh, sculpticell breadth 3 × length; pronotal median base with shallow isodiametric and transverse mesh; elytral disc with shallow transverse mesh, sculpticells 2 –3× length; elytral apex with shallow transverse mesh, sculpticell breadth 2 × length; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex glossy rufopiceous; antennomeres 1-3 flavous, 4-11 only slightly darker; pronotal disc rufopiceous; pronotal lateral margins, anterior callosity and median base rufoflavous to flavous at outer margins; proepipleuron flavous, proepisternum rufobrunneous; elytral intervals 2-8 rufopiceous, sutural interval rufoflavous basally, flavous apically; interval 9, marginal depression, and apical margin rufoflavous; elytral epipleuron flavous dorsally, rufoflavous along ventral margin, metepisternum rufobrunneous; abdomen with ventrites 1-5 rufopiceous medially, rufoflavous laterally; apical ventrite 6 flavous in apical half; metafemur flavous; metatibia flavous with brunneous cast.

Male genitalia (n = 1). Aedeagal median lobe gracile, distance from parameral articulation to tip 4.5 × depth at midlength (Fig. 22A), apex broad, extended twice its breadth beyond ostial opening, tip flattened on dorsoapical aspect; median lobe slightly curved to the right before rounded tip in ventral view (Fig. 22B); internal sac covered with evident microspicules, a flagellar plate visible inside dorsal margin in lateral view (Fig. 22A).

Female reproductive tract (n = 1). Bursa copulatrix columnar, nearly as broad as vagina, length 0.54 mm, breadth 0.23 mm (Fig. 17D); bursal walls translucent, distinctly wrinkled; gonocoxite 1 with 3-4 apical fringe setae, 4-5 smaller setae on medial surface (Fig. 18D); gonocoxite 2 subtriangular, apex acuminate, lateral surface distinctly curved, 2 small lateral ensiform setae, apical nematiform setae on medial surface at 0.75 × gonocoxite length.

Holotype.

Male (CUIC) dissected and labeled: HI: Maui Haleakala N.P. / Kuiki, below el. 2134 m / N20°42.23', W156°08.00', / 16-V-2001 lot 02 sift. / litter under ohia lehua / J.K. Liebherr // Mecyclothorax / montanus / ♂ #1 / Det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / montanus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes.

HI: Maui: Haleakala N.P., Kipahulu Vy., sift litter by day, 2100 m el., 07-v-1991 lot 05, Jessel/Medeiros (CUIC, 2), Mauka Ridge, pyrethrin fog Metrosideros /moss, 2045 m el., 21-v-1998 lot 01, Polhemus (NMNH, 1), Kuiki, below, sift Metrosideros litter, 2145 m el., 16-v-2001 lot 02, Liebherr (CUIC, 6), pyrethrin fog Metrosideros /moss, 2145 m el., 16-v-2001 lot 01, Liebherr (CUIC, 1).

Etymology.

The adjectival epithet montanus means of the mountains, which aptly fits the habits of this species distributed around the head of Kīpahulu Valley.

Distribution and habitat.

Mecyclothorax montanus is distributed in the upper slopes surrounding the head of Kīpahulu Valley (Fig. 21). Beetles have been found in sifted leaf litter from the forest floor, and also in leaf and moss litter adhering to trunks of ‘ōhi‘a.