Mecyclothorax cymindulus, 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 : 67-70

Taxon classification Animalia Coleoptera Carabidae

(024) Mecyclothorax cymindulus sp. n. Figs 34N, 37C, 38B, 39A, 40

Diagnosis.

Differing from its most similar species group member Mecyclothorax cymindicus (Fig. 38 A–B) by: 1, pronotal hind angles obtuse due to rounded basal margin posterad angle, the pronotal lateral margin subparallel anterad angle; 2, broad, minutely punctate discal elytral striae over basal half of length; 3, elytra with transverse-mesh microsculpture on the sutural interval, and parallel-lined microsculpture laterally on disc and at apex. If a male is available, the aedeagal median lobe of Mecyclothorax cymindulus has a more flattened apex with a subangulate, ventrally angled tip (Fig. 34N), versus the more rounded apex with ventrally expanded tip of male Mecyclothorax cymindicus (Fig. 34 M). Setal formula 2 2 2 2. Standardized body length 4.1-4.6 mm.

Description

(n = 5). Head capsule with frontal grooves straight, a lateral carina to anterior supraorbital seta; dorsal surface of neck flat to slightly concave; ocular lobe moderately extended from gena, eyes not covering posterior portion of lobe, ocular ratio = 1.34-1.41, ocular lobe ratio = 0.70-0.76; labral anterior margin subangulately excavated medially to 0.2 × length; antennae broader in apical half, submoniliform, antennomeres 2-3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum moderately transverse, MPW/PL = 1.21-1.25, base broad, MPW/BPW = 1.41-1.49; median base depressed relative to disc, covered with irregular punctures and longitudinal wrinkles; basal margin slightly convex between laterobasal depressions; median longitudinal impression shallow, very finely incised at depth; anterior transverse impression very shallow, broad, crossed by fine longitudinal wrinkles; anterior callosity slightly convex, crossed by numerous wrinkles; front angles not projected, rounded; anterior and basal widths subequal, APW/BPW = 0.95-1.04; lateral marginal depression broader, beaded at front angle, evenly expanded along midlength, moderately broad and upturned toward basal angle; laterobasal depression smooth, broad, with or without convex median extension from disc. Proepisternum with 6 punctures along hind marginal groove; prosternal process medially depressed, a broad marginal bead laterally. Elytra with convex disc, sides more sloped; basal groove straight from sutural stria laterally to subangulate humeri; elytral slightly narrowed basally, subquadrate, MEW/HuW = 1.83-1.95; parascutellar seta present; parascutellar striole with 4-5 punctures, continuous between punctures; sutural interval more convex than lateral intervals; sutural and 2nd striae of subequal depth from base to apex; discal striae 1-5 and base of 6 minutely punctate, striae slightly irregular, associated intervals slightly convex; 7th and 8th interval of similar convexity mesad subapical sinuation; 2 dorsal elytral setae at 0. 25 –0.27× and 0.57 –0.59× elytral length, setal impressions extended over 2/3 width of interval 3; apical and subapical setae present; lateral elytral setae arranged as anterior series of 7 setae, posterior series of 6 setae; ely tral marginal depression broadest at humerus, gradually narrowed to a beadlike margin at subapical sinuation; subapical sinuation shallow, abruptly incurved anteriorly. Mesepisternum with ~10 punctures in 2 rows; metepisternal width to length ratio = 0.79; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1-5; suture between ventrites 2 and 3 reduced, effaced laterally; apical male ventrite with 2 marginal setae, apical female ventrite with 4 equally spaced marginal setae and a median trapezoid of 4 subequally short setae. Legs-metatarsomere 1/metatibial length ratio = 0.17; metatarsomere 4 length along outer lobe 1.35 × medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci deep, broad, basal tarsomeres medially carinate. Microsculpture of vertex transverse, sculpticell breadth 2 × length; pronotal disc with transverse mesh, sculpticell breadth 3 –4× length; pronotal median base with distinct isodiametric and transverse sculpticells; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomeres 1-3 flavous, 4-11 rufobrunneous; pronotal disc rufobrunneous, pronotal margins slightly paler; proepipleuron and proepisternum rufoflavous; elytral disc rufobrunneous, metallic reflection present due to microsculpture; sutural interval rufous basally, flavous apically; elytral marginal depression narrowly flavous, apex flavous to juncture of intervals 3 and 4; elytral epipleuron flavous, metepisternum rufoflavous; abdomen with ventrites 1-6 medially rufoflavous, laterally flavous, ventrite 6 with apical half flavous; metafemur flavous; metatibia rufoflavous.

Male genitalia (n = 1). Aedeagal median lobe gracile, distance from parameral articulation to tip 4.0 × depth at midlength (Fig. 34N); apex moderately extended beyond ostial opening, apical face flat, tip distinctly angulate at juncture of apical face and ventral margin; internal sac with lightly sclerotized dorsal microtrichial patch, and ventral face covered with fine spicules; flagellar plate length 0.47 × parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar with rounded apex, narrowed along midlength, length 0.93 mm, medial breadth 0.31 mm, basal breadth at vagina 0.43 mm (Fig. 39A); bursal walls translucent with thin wrinkles; gonocoxite 1 with 2-3 apical fringe setae and 6-7 smaller setae on medial surface (Fig. 37C); gonocoxite 2 narrowly subtriangular with broad apex, tip tightly rounded, 1-2 lateral ensiform setae, apical nematiform setae on medioventral surface at 0.76 × gonocoxite length.

Holotype.

Female (BPBM) labeled: Kipahulu Valley / Maui Camp 1 / 945 m, 6-12.VIII.67 // N. Wilson / Collector / BISHOP //? cymindicus (E.C.Z. handwriting) // HOLOTYPE / Mecyclothorax / cymindulus / Liebherr / J.K. Liebherr 2015 (black-margined red label).

Paratypes.

HI: Maui: Haleakala N.P., Kipahulu Vy., sift litter, 1500 m el., 09-v-1991 lot 03, Jessel/Medeiros (CUIC, 1), Mauka Ridge, pyrethrin fog Metrosideros /moss, 2055 m el., 21-v-1998 lot 01, Polhemus (NMNH, 1), West Camp, pyrethrin fog Metrosideros /moss, 1960 m el., 20-v-1998 lot 01, Polhemus (CUIC, 1; NMNH, 2).

Etymology.

This epithet is taken from the Latin noun cymindis, meaning night hawk, modified with the diminutive ending -ule. Beetles of this species are the same size as those of Mecyclothorax cymindicus , but use of the common stem for the epithet is meant to connote the two species’ affinities; a convention used by Perrault (1984, 1986, 1988, 1989) to deal with the rampant Mecyclothorax diversity of Tahiti.

Distribution and habitat.

Beetles of Mecyclothorax cymindulus are recorded only from Kīpahulu Valley, 945-2055 m elevations (Fig. 40). They have been discovered in sifted leaf litter or on mossy ‘ōhi‘a trunks.