Mecyclothorax hephaestoides, 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 : 265-269

Taxon classification Animalia Coleoptera Carabidae

(106) Mecyclothorax hephaestoides sp. n. Figs 143A, 144 A–C, 145A, 146A, 147

Diagnosis.

Beetles of this species are larger than all others assigned to this species group, standardized body length 5.7-6.0 mm (Fig. 143A), and are the only ones with a quadrisetose pronotum. Body coloration is uniformly dark, rufopiceous to rufobrunneous, with the elytral margins only narrowly rufoflavous. The discal elytral striae are distinctly punctate, with striae 1-3 impressed on the disc, and striae 4-5 indicated by more isolated punctures. Both the apical and subapical elytral setae are present. Setal formula 2 2 2 2.

Description

(n = 5). Head capsule with frontal grooves deep near clypeus, divergent mesad broad lateral convexity anterad eye, parallel mesad anterior supraorbital seta; dorsal impression of neck distinct, concave, visible in dorsal view; ocular lobe obtusely protruded from gena, eyes moderately convex, ocular ratio = 1.44-1.51, not covering posterior portion of ocular lobe, ocular lobe ratio = 0.76-0.81; labral anterior margin broadly emarginate to 1/6 of labral length; antennae filiform, antennomeres 2-3 with only a few setae basad apical rings; mentum tooth with sides acute, apex tightly rounded. Pronotum moderately transverse, MPW/PL = 1.20-1.25, lateral margins subparallel laterad basal pronotal setal articulatory sockets, hind angles obtuse, apex tightly rounded; median base depressed relative to disc,>20 distinct punctures each side, the punctures elongate along juncture with disc; basal margin broadly convex between laterobasal depressions; median longitudinal impression very fine, obsolete on disc, distinct just anterad median base; anterior transverse impression finely incised, deep, small punctures in deepest part; anterior callosity convex, smooth; front angles not produced, rounded posterad front margin; pronotal apical width subequal to pronotal basal width, APW/BPW = 0.99-1.07; lateral marginal depression moderately broad, reflexed, broader with minute bead at front angle; laterobasal depression deep, surface irregular, continuous with lateral depression. Proepisternum with 5 distinct punctures along hind marginal groove; prosternal process with broad median depression, lateral margins broadly beaded between coxae. Elytra subquadrate, disc moderately convex, sides evenly sloped to lateral marginal depression; basal groove subangulate at sutural stria, extended laterally to rounded humerus defined by a hitch at the juncture of narrow basal groove and broader lateral depression, MEW/HuW ratio = 2.06-2.12; parascutellar seta present; parascutellar striole with 5-7 punctures, striole shallow to coplanar with disc between punctures; sutural interval more convex than lateral intervals throughout length; sutural stria traceable to basal groove, deep and narrow apically, 2nd stria obsolete basally, shallow and broad apically; discal striae 3-5 progressively shallower and less extended apically, all absent from base, stria 6 represented by a few very shallow punctures or absent, stria 7 absent; 8th interval convex 7th stria at position of subapical elytral seta; 2 dorsal elytral setae at 0.29 × and 0.62-0.64 elytral length, setal impressions evident but spanning only ½ width of interval 3; apical and subapical setae present; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 5-7 setae; elytral marginal depression narrow, edge slightly upraised at humerus, narrowed to bead at subapical sinuation; subapical sinuation shallow, more abruptly incurved apically. Mesepisternum with ~12 punctures in 2-3 rows; metepisternal width to length ratio = 0.69; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1-6, lateral depressions on ventrites 3-6; suture between ventrites 2 and 3 complete; apical male ventrite with 2 marginal setae and apical female ventrite with 4 equally spaced setae and median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.17; metatarsomere 4 length along outer lobe 1.3 × medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, lateral, median area broad. Microsculpture of vertex a shallow transverse mesh, sculpticell breadth 2 –3× length; pronotal disc with indistinct elongate transverse mesh to transverse lines, transverse sculpticell breadth 2 –4× length, median base with distinct transverse mesh between punctures, sculpticell breadth 2 –3× length; elytral disc and apex with distinct, regular transverse mesh, sculpticell breadth 2 –3× length; metasternum with obsolete transverse mesh, the surface glossy; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous with piceous cast; antennomeres 1-3 rufoflavous, 4-11 rufobrunneous; pronotal disc rufopiceous, lateral margins narrowly, and base and apex more broadly rufobrunneous; proepipleuron rufobrunneous dorsally, rufoflavous along ventral margin, proepisternum dark rufobrunneous; elytral disc rufopiceous, sutural interval narrowly rufous along suture in basal 2/3, narrowly rufoflavous apically; elytral lateral marginal depression narrowly rufoflavous, elytral apex narrowly rufoflavous apicad subapical sinuation; elytral epipleuron dark rufoflavous, ventrally rufopiceous, metepisternum rufopiceous with cupreous reflection; abdominal ventrites 1-6 rufobrunneous mediobasally, rufoflavous on lateral and apical margins except apical 1/3 of ventrite 6 paler, rufobrunneous; metafemur rufoflavous with basal piceous cloud; metatibia rufoflavous with brunneous cast.

Male genitalia (n = 4). Aedeagal median lobe elongate, gracile, distance from parameral articulation to tip 4.2 × depth at midlength (Fig. 144A, C); apex elongate, narrowly extended 5 × its minimum depth beyond ostial opening, the tip expanded dorsally as a blunt tooth, and ventrally as rounded tip with oblique, straight, apical face; median lobe straight in ventral view, but apex offset to right side, dorsal (left) margin straight in ventral view, but apex offset to right side, dorsal (left) margin angled to meet thin apex (Fig. 144B); internal sac broad, breadth about 0.67 × distance from ventral ostial margin to base of flagellar plate, a broad, transverse dorsal ostial microtrichial patch defined by shingled macrospicules present near base; flagellar plate moderately long, length 0.42 × parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar with expanded apex, length 1.50 mm, apical breadth 0.68 mm, basal breadth 0.34 mm (Fig. 145A); bursal walls translucent, thickly wrinkled; gonocoxite 1 with 4-5 apical fringe setae, the medial seta smaller, a curved seta at medioapical angle and 6-7 smaller setae on medial surface (Fig. 146A); gonocoxite 2 falcate with subacuminate apex, broad basal extension little curved at lateral terminus, 2 lateral ensiform setae, apical nematiform setae on medioventral surface at 0.71 × gonocoxite length.

Holotype.

Male (CUIC) dissected and labeled: HI: Maui Haleakala N.P. / Halemau‘u Tr. 5-V-1991 / el. 2270-2300 m / at night on ground // J.K. Liebherr / A.C. Medeiros, / Jr. collectors // 3 // Mecyclothorax / hephaestoides / ♂ #2 / det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / hephaestoides / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes.

HI: Maui: Haleakala N.P., Kalapawili Ridge nr. Pohaku Polaha, base bunch grass, 2505 m el., 11-x-2009 lot 01, Krushelnycky (UHIM, 1), Kipahulu Vy., sifting litter by day, 2100 m el., 07-v-1991 lot 05, Jessel/Medeiros (CUIC, 2), below Kuiki, pyrethrin fog mossy rockface, 2145 m el., 16-v-2001 lot 03, Liebherr (CUIC, 2), sift Metrosideros litter, 2145 m el., 16-v-2001 lot 02, Liebherr (CUIC, 1), Leleiwi overlook, under stone on ground, 2010-2100 m el., 11-vii-1919, Timberlake (UCRC, 1), NW upper slope, Halemauu Tr., on ground at night 2270-2300 m el., 05-v-1991 lot 03, Liebherr/Medeiros (CUIC, 1), under rocks nr. roots, 2285-2315 m el., 05-v- 1991 lot 02, Liebherr (CUIC, 1), Waikamoi Gulch headwaters, moss along stream, 2030 m el., 06-v-1991 lot 01, Liebherr (CUIC, 1); Hana For. Res., Hanawi N.A.R., Kuhiwa Str. E Poouli Cabin, under rocks in streambed, 1615 m el., 06-v-1998 lot 03, Ewing (CUIC, 1); Koolau For. Res.; Waikamoi N.C.P., Honomanu drainage transect 3, ex mossy trunk Metrosideros , 1830-1860 m el., 07-v-1991 lot 07, Liebherr (CUIC, 5), upper arm Honomanu drainage, treading streamside vegetation, 1950 m el., 07-v-1991 lot 06, Liebherr (CUIC, 2).

Etymology.

This species resembles Mecyclothorax vulcanus (Blackburn) and Mecyclothorax hephaestus Liebherr of Hawai‘i Island ( Liebherr 2008b), leading to use of hephaestoides as the species epithet.

Distribution and habitat.

Mecyclothorax hephaestoides exhibits a bipartite distribution with apparently disjunct populations occupying the Waikamoi area, and high elevations surrounding the head of Kīpahulu Valley (Fig. 147). This species occupies higher elevation forest and open subalpine habitats above timberline; i.e., 1615-2505 m elevation. Beetles of this species have been found under rocks in open rocky habitat within the fog zone, in moss along a stream, by treading emergent vegetation along a stream, in Deschampsia (hairgrass) tufts, and on a mossy rockface. The common element in all of these situations was the presence of free moisture, often at or just below the trade wind inversion layer on the volcano.