Mecyclothorax reiteratus, 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 : 206-210

Taxon classification Animalia Coleoptera Carabidae

(086) Mecyclothorax reiteratus sp. n. Figs 102B, 104B, 105B, 106, 107

Diagnosis.

This species (Fig. 102B) and Mecyclothorax splendidus (Fig. 102C) represent the only species in the group characterized by a bisetose pronotum, the lateral seta present and hind angles glabrous. In beetles of these species both supraorbital setae are present, and in this species both apical and subapical setae are absent; setal formula 2 1 2 0. The discal elytral intervals 2-4 are flat to even slightly concave, in agreement with Mecyclothorax iteratus but diagnostically different from Mecyclothorax splendidus , which exhibits slightly convex discal intervals. Elytral proportions vary among individuals, but the humeri-defined by the angle at the juncture of the basal groove and lateral marginal depression-tend to be more proximate in these beetles; MEW/HuW = 2.45-2.56 versus MEW/HuW = 2.39-2.49 in Mecyclothorax splendidus . The male aedeagal median lobe is very diagnostic, with males of this species exhibiting a rounded tip with a short "crochet hook" dorsal projection (Fig. 107), not the broadly expanded lobe apex of Mecyclothorax iteratus (Fig. 103) nor the slightly dorsoventrally expanded apex of Mecyclothorax splendidus (Fig. 108). Standardized body length 4.5-5.4 mm.

Description

(n = 5). Head capsule with frontal grooves slightly sinuous, broad medial face transversely wrinkled, narrow lateral carina mesad anterior supraorbital seta; dorsal impression of neck broadly concave, visible dorsally; eyes convex, ocular ratio = 1.56-1.71, covering much of protruded ocular lobe, ocular lobe ratio = 0.82-0.90; labral anterior margin shallowly emarginate to 1/7 labral length; antennae filiform, antennomeres 2-3 with sparse pelage of short setae; mentum tooth with sides acute, apex rounded, margins beaded. Pronotum appearing longer than broad, but MPW/PL = 1.08-1.11, base constricted, MPW/BPW = 1.53-1.62; hind angles slightly acute, sharply angled, lateral margins subparallel to convergent for 0.1 × length; median base depressed relative to disc, ~25 elongate punctures each side separated by smooth cuticle; basal margin straight between hind angles; median longitudinal impression finely incised, broader on front of median base, crossed by indistinct transverse wrinkles; anterior transverse impression deeply incised, crossed by distinct longitudinal wrinkles medially, narrower and smoother mesad front angle; anterior callosity flat, crossed by dense wrinkles of bordering impression; front angles slightly projected, tightly rounded; apical pronotal width subequal to greater than basal width, APW/BPW = 0.99-1.08; lateral marginal depression very narrow, beaded laterally, slightly broader with upturned edge at front angle, upraised outside laterobasal depression; laterobasal depression an irregular continuation of lateral depression, margin beaded laterally. Proepisternum with 5 distinct punctures along hind marginal groove, small carinae between some punctures; prosternal process with very broad median depression, lateral margins broadly upraised. Elytra elongate obovoid, disc flat medially, sides distinctly sloped to margins; basal groove slightly curved to angulate humerus at juncture with lateral marginal depression, humeri proximate, lateral margins narrowly rounded, MEW/HuW = 2.45-2.56; parascutellar seta present; parascutellar striole with 5 isolated punctures, striole interrupted between punctures; sutural interval nearly coplanar with lateral intervals throughout length; sutural stria marked by proximate isolated punctures, very shallowly impressed, striae 2-5 with punctures progressively more isolated; discal intervals 2-4 flat to concave, intervals 5-8 following curvature of elytron; 7th and 8th intervals laterad apex of 7th stria of same convexity; 2 dorsal elytral setae at 0.30 –0.31× and 0.66 –0.70× elytral length, setal impressions shallow, spanning ½ width of interval 3; apical and subapical setae absent; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression moderately narrow, edge upturned at humerus, depression lined with isodiametric sculpticells in anterior half, narrowed in apical 1/3 to subapical sinuation; subapical sinuation shallow, symmetrical. Mesepisternum with ~14 punctures in 2-3 rows; metepisternal width to length ratio = 0.75; metepisternum/metepimeron suture distinct. Abdomen with irregular longitudinal wrinkles laterally on ventrites 1-6, rounded lateral depressions on ventrites 3-6; suture between ventrites 2 and 3 effaced; apical male ventrite with 2 marginal setae and apical female ventrite with 4 equally spaced marginal setae and median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.20; metatarsomere 4 length along outer lobe 1.4 × medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, lateral, median surface granulate. Microsculpture of vertex a transverse mesh, sculpticell breadth 2 × length, on frons, sculpticells 3 –4× broad as long on neck; pronotal disc with indistinct transverse mesh to transverse lines; pronotal median base with isodiametric sculpticells medially, transverse cells laterally; elytral disc with isodiametric mesh medially, transverse sculpticells on lateral intervals, apex with shallow isodiametric mesh; metasternum with transverse lines to transverse mesh, the sculpticell breadth 2 × length; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufous with piceous cast in frontal grooves; antennomere 1 rufoflavous, antennomeres 2-11 rufobrunneous; pronotal disc rufopiceous, lateral margins narrowly, and base and apex broadly, rufous; proepipleuron rufoflavous, proepisternum rufobrunneous; elytral disc rufous with piceous cast, sutural interval pale rufous laterad scutellum to apex, elytral lateral margins slightly paler, rufobrunneous, apex broadly rufoflavous; elytral epipleuron rufoflavous, metepisternum rufobrunneous; abdominal ventrites 1-5 rufous, laterally and apically on ventrite 6 rufoflavous; metafemur flavous, apex with a rufobrunneous cast that matches rufobrunneous metatibia.

Male genitalia (n = 6). Aedeagal median lobe moderately robust, distance from parameral articulation to tip 3.4 –3.8× depth at midlength (Fig. 107A, C–D); apex extended for 1.5 × its depth beyond ostial opening, dorsal surface expanded into a bluntly acute tooth, surface of tip rounded apicad tooth; median lobe curved rightward nearly 90° apically in ventral view, right margin evenly concave, left margin sinuous-convex then slight concave-before rounded, slightly expanded tip (Fig. 107B); internal sac with discrete, ovoid dorsal ostial microtrichial patch comprised of macrospicules situated near sac base, and broadly diffuse field of dark microspicules covering ventral surface (Fig. 107C); flagellar plate large and robust, length 0.55 × parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar, narrow and elongate, apex rounded, length 1.14 mm, rounded apex breadth 0.45 mm, basal breadth 0.34 mm (Fig. 104B); bursal walls translucent, thickly wrinkled; gonocoxite 1 with 3-5 apical fringe setae, a thick seta at medioapical angle and 5-6 setae along medial surface (Fig. 105B); gonocoxite 2 broadly subtriangular, tip tightly rounded, base thinly extended laterally, 2 elongate lateral ensiform setae, apical nematiform setae on medioventral surface at 0.73 × gonocoxite length.

Holotype.

Male (CUIC) dissected and labeled: HI:East Maui Waikamoi / Flume 26-V-1997 lot06 / 1300 m el. beat ohia / in day J.K. Liebherr // Mecyclothorax / reiteratus / ♂ #21/ det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / reiteratus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes.

HI: Maui: Koolau For. Res., Hanawi N.A.R., 1630 m el., vi-1997, Gruner (UHIM, 1), Tetraplasandra dipyrena , 1615 m el., 03-viii-1973, Gagné (BPBM, 1), Koolau Gap, Halehaku, beat ferns at night, 1325 m el., 13-v-1998 lot 09, Liebherr (CUIC, 5), beat Metrosideros /moss, 1325 n el., 13-v-1998 lot 11, Polhemus (NMNH, 5), beat Rubus (akala) at night, 1325 m el., 13-v-1998 lot 08, Liebherr (CUIC, 4), pyrethrin fog Cibotium /log, 1325 m el., 13-v-1998 lot 03, Liebherr (CUIC, 1), pyrethrin fog Metrosideros , 1325 m el., 13-v-1998 lot 04, Liebherr (CUIC, 2), pyrethrin fog Metrosideros /moss, 1325 m el., 13-v-1998 lot 01, Liebherr (CUIC, 3), lot 02, Liebherr (CUIC, 1), Waikamoi Gulch, Waikamoi Flume, beat/scrape Metrosideros , 1310 m el., 26-v-1997 lot 06, Liebherr (CUIC, 1).

Etymology.

Beetles of this species are similar to those of Mecyclothorax iteratus , and so use of the same stem plus a prefix can signify that similarity. The epithet reiteratus represents a redundancy of iteratus -to repeat-so this species repeats again a similar habitus with differences most pronounced in one setational and more male genitalic characters.

Distribution and habitat.

Distributional records for Mecyclothorax reiteratus lie at the lower elevational distributional margin of Mecyclothorax iteratus , with records from Waikamoi Flume, Ko‘olau Gap/ Ke‘anae Valley, and Hanawī (Fig. 106). The localities span 1310-2065 m elevation. The predominant plant substrate is ‘ōhi‘a, but specimens have also been collected on Cibotium ( hāpu‘u), Rubus ( ‘ākala), and Polyscias ('ohe).