Mecyclothorax planipennis, 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 : 162-165

Taxon classification Animalia Coleoptera Carabidae

(066) Mecyclothorax planipennis sp. n. Figs 82 E–H, 83B, 84B, 86, 87A

Diagnosis.

This species (Fig. 87A) and Mecyclothorax planatus (Fig. 87B) comprise the third sister-species pair within the Haleakalā Mecyclothorax argutor group fauna. Their adelphotaxon status is supported by the broad depressions of the elytra; an anterior depression centered each side on the anterior dorsal elytral seta, and a posterior depression implicating intervals 1-5 and lying posterolaterad of the posterior dorsal elytral seta. A second synapomorphy for the pair is the presence of four marginal setae on the male apical abdominal ventrite, a character not observed in any other Hawaiian Mecyclothorax species. Mecyclothorax planipennis can be differentiated from Mecyclothorax planatus by: 1, elytral intervals slightly convex near anterior dorsal elytral seta, not flat as in Mecyclothorax planatus ; 2, pronotum tending to be relatively less constricted basally, MPW/BPW = 1.45-1.50 versus values of 1.49-1.60 in Mecyclothorax planatus , that basal constriction leading to a diagnostic difference in apical versus basal pronotal widths, APW/BPW = 1.02-1.05 for Mecyclothorax planipennis versus APW/BPW = 1.06-1.15 for Mecyclothorax planatus . Although these species are exceedingly similar in outward appearance, the male aedeagal median lobes differ distinctively. The median lobe tip of Mecyclothorax planipennis males is pointed (Fig. 82 E–H), whereas the median lobe tip of Mecyclothorax planatus males is bluntly rounded (Fig. 82 I–L). Setal formula 2 2 2 2. Standardized body length 5.2-5.7 mm.

Description

(n = 5). Head capsule with frontal grooves broad near clypeus, a broad lateral carina posterad to anterior supraorbital seta; dorsal surface of neck flat to convex; eyes moderately convex, ocular lobe obtusely extended from gena, ocular ratio = 1.41-1.51, ocular lobe ratio = 0.72-0.80; labral anterior margin broadly, shallowly emarginate; antennae filiform, antennomere 3 sparsely setose; mentum tooth with sides acute, apex tightly rounded. Pronotum transverse, MPW/PL = 1.30-1.39; hind angle right, margin behind rounded, lateral margin subparallel to slightly convergent for short distance anterad angle; median base depressed relative to disc, covered with rugose wrinkles and punctures; basal margin broadly convex medially; median longitudinal impression fine, shallow; anterior transverse impression broad, bordered anteriorly by depressed to slightly convex anterior callosity, the callosity crossed by numerous, densely packed longitudinal wrinkles; front angles slightly projected, rounded; lateral marginal depression moderately narrow, edge upturned; laterobasal depression broadly concave. Proepisternum with 6 punctures along hind marginal groove; prosternal process medially concave, margins broadly upraised. Elytra subquadrate, disc flattened due to anterior elytral depressions, sides moderately sloped; basal groove evenly curved to subangulate juncture with lateral marginal depression, the lateral marginal depression broader than basal groove, MEW/HuW = 1.83-1.92; parascutellar seta present; parascutellar striole shallow, with 6-7 punctures; sutural interval more convex than lateral intervals, sutural juncture upraised; sutural and 2nd striae of subequal depth from base to apex; discal striae 1-4 punctate in basal 2/3 of length, stria 5 continuous, striae 6-7 obsolete laterally, striae 1-5 and 7 evident at elytral apex; 8th interval convexly elevated immediately laterad 7th stria; 2 dorsal elytral setae at 0.26 –0.29× and 0.54 –0.60× elytral length, setal impression spanning 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, broad. Mesepisternum with ~14 punctures in 2-3 rows; metepisternal width to length ratio = 0.75; metepisternum/metepimeron suture distinct. Abdomen with 1-2 longitudinal, lateral wrinkles on ventrites 1-4; suture between ventrites 2 and 3 complete; apical male ventrite with 4 equally spaced marginal setae (a 5th unilateral seta in one individual), apical female ventrite with 4 equally space marginal setae and median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.19; metatarsomere 4 length along outer lobe 1.3 × medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, canaliculated, median carina broad. Microsculpture of vertex upraised isodiametric sculpticells in transverse rows; pronotal disc with isodiametric sculpticells in transverse rows, median base with upraised isodiametric mesh; elytral disc with upraised isodiametric sculpticells in transverse rows, apex with upraised isodiametric sculpticells; metasternum with transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex brunneous with piceous cast; antennomeres 1-3 rufoflavous, 4-11 darker, with piceous cast; pronotal disc rufobrunneous with piceous cast, margins paler, rufoflavous in lateral depression; proepipleuron rufoflavous, proepisternum rufobrunneous with piceous cast; elytral disc reflective rufobrunneous, sutural interval rufous basally, rufoflavous apically; elytral margins narrowly rufoflavous in lateral depression, apex slightly, broadly paler; elytral epipleuron rufoflavous, metepisternum rufopiceous; abdomen uniformly dark, rufopiceous, apical abdominal ventrite very narrowly paler, rufoflavous; metafemur with basal half rufopiceous, apex flavous; metatibia rufobrunneous with piceous cast.

Male genitalia (n = 3). Aedeagal median lobe robust, distance from parameral articulation to tip 3.2 × depth at midlength (Fig. 82E, G–H); apex briefly extended beyond ostial opening, apical face broadly flattened, tip acutely angulate, slightly downturned; median lobe straight in ventral view (Fig. 82F), right margin indented before rounded tip in this view, left margin slightly curved; internal sac with ventral surface covered with denser microspicules (Fig. 82 G–H), a ventral ostial microtrichial patch either present (Fig. 82H) or absent (Fig. 82G) near sac base; flagellar plate large, length 0.56 –0.61× parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar, elongate, length 0.97 mm, breadth 0.34 mm (Fig. 83B); bursal walls moderately opaque, thickly wrinkled; gonocoxite 1 with 2-3 apical fringe setae and 3-4 smaller setae on medial surface (Fig. 84B); gonocoxite 2 falcate, tip pointed, base broadly extended laterally, 2 stout, apically narrowed lateral ensiform setae, apical nematiform setae on medial surface at 0.73 × gonocoxite length.

Holotype.

Female (BPBM) labeled: Paliku, Haleakala / Crater, Maui 6500', / near Kaupo Trail / VII-22-65 // J.W. Beardsley / Collector // HOLOTYPE / Mecyclothorax / planipennis / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes.

HI: Maui: Haleakala N.P., Haleakala Crater, Paliku, banana bait trap, 1960 m el., 25-vii-1962, Hardy (BPBM, 1), diphacinone bait station, 1830- 1950 m el., 21-x-1997, Takumi (BPBM, 1), 8-i-1998, Takumi (BPBM, 1), 01-v-2008, Kaholoa‘a (BPBM, 1), Kipahulu Vy., West Camp, pyrethrin fog Metrosideros /moss, 1960 m el., 19-v-1998 lot 01, Polhemus (NMNH, 3), below Kuiki, sift Metrosideros litter, 2145 m el., 16-v-2001 lot 02, Liebherr (CUIC, 6); Hana For. Res., Waihoi Vy., 1372 m el., 12-vii-1981, Montgomery (BPBM, 1).

Etymology.

The species epithet planipennis compounds the Latin planus, or even, flat, with the plural of penna, or wing; therefore planipennis , flat wings. The species epithet is treated as a noun in apposition.

Distribution and habitat.

Mecyclothorax planipennis is distributed from Paliku on the west to Waiho‘i Valley on the east, and across upper Kīpahulu Valley from West Camp on the north to Kuiki on the south (Fig. 86). Locality elevations range 1372-2145 m. Beetles have been found on mossy ‘ōhi‘a trunks and in ‘ōhi‘a leaf litter. They have also entered banana bait traps (Hardy, BPBM) and diphacinone rat traps (Takumi Kaholoa‘a, BPBM).