Mecyclothorax brevidux, 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 : 261-262

Taxon classification Animalia Coleoptera Carabidae

(105) Mecyclothorax brevidux sp. n. Figs 136E, 137E, 140 C–D, 141 F–I, 142

Diagnosis.

This species is extremely similar to Mecyclothorax longidux (Fig. 140 A–B), but can be diagnosed from that species by the less punctate discal striae, with small punctures present in impressed striae 1-2 to 1-3, and striae 4-5 reduced to linear series of small punctures (Fig. 140 C–D). The discal elytral intervals are less convex than in Mecyclothorax longidux , though the sutural interval is as upraised as in that species. The metafemur is darkened in its basal 1/5 to 1/3 of length, with the middle of the femur flavous, and apex narrowly piceous to match the darkened metatibia. The male aedeagal median lobe apex is shorter and broader (Fig. 141 F–I) than in males of Mecyclothorax longidux (Fig. 141 A–B, D). Setal formula 2 1 2 0. Standardized body length 5.2-5.9 mm.

Description

(n = 5). [The above description of Mecyclothorax longidux can serve to describe this species with the following substitutions.] Eyes with ocular ratio = 1.50-1.58, ocular lobe ratio = 0.81-0.84. Pronotum with lateral margins subparallel to slightly divergent for 0.1 × pronotal length anterad slightly obtuse, projected hind angles; MPW/PL = 1.15-1.21, MPW/BPW = 1.51-1.63, APW/BPW = 1.0-1.07. Elytra subovoid, MEW/HuW = 2.20-2.49. Microsculpture of elytral disc and apex minimally developed, with indistinct isodiametric and transverse sculpticells visible through the glossy reflection.

Male genitalia (n = 4). Aedeagal median lobe gracile, distance from parameral articulation to tip 3.3 –3.6× depth at midlength (Figs 141 F–H); apex broad, extended twice maximum depth beyond ostial opening, apical face flattened, tip ventrally expanded so that ventral margin of lobe curves downward; internal sac short, broad, with lightly melanized dorsal ostial microtrichial patch and ventral ostial microtrichial patch (Fig. 141I); flagellar plate of moderate size, length 0.39 × parameral articulation-tip distance (larger ratio of plate size relative to Mecyclothorax longidux due to shorter median lobe in Mecyclothorax brevidux ; compare Fig. 141D, I)

Female reproductive tract (n = 1). Bursa copulatrix short, sac-shaped, length 1.0 mm, maximum width 0.51 mm, basal constriction 0.40 mm broad (Fig. 136E); bursal walls thick, broadly wrinkled; gonocoxite 1 with 4 apical fringe setae, a curved seta at medioapical angle and 5 setae on medial surface (Fig. 137E); gonocoxite 2 subacuminate, apex tightly rounded, basal extension curved at lateral terminus, 2 moderately elongate lateral ensiform setae, apical nematiform setae on medioventral surface at 0.74 × gonocoxite length.

Holotype.

Female (BPBM) labeled: Kipahulu Valley / Maui, Camp 1 / 945 m, 6-12.VIII.67 // N. Wilson / Collector / BISHOP // 4 // HOLOTYPE / Mecyclothorax / brevidux / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes.

HI: Maui: Haleakala N.P., Kekuewa Hill, 0.7 km N Puu Ahulili, sift humus/moss, 1600 m el., 16-v-1993 lot 02, Liebherr/Medeiros (CUIC, 4), lot 04 Liebherr/Medeiros (CUIC, 1), vegetation at night, 1600 m el., 16-v-1993 lot 08, Liebherr/Medeiros (CUIC, 1), Kipahulu Vy., sift litter, 1500 m el., 09-v-1991 lot 03, Jessel/Medeiros (CUIC, 1), 1800 m el., 08-v-1991 lot 04, Jessel/Medeiros (CUIC, 1), Mauka Ridge, pyrethrin fog Metrosideros /moss, 2045 m el., 21-v-1998 lot 01, Polhemus (NMNH, 2), Kipahulu west rim ESE Kuiki, sift Metrosideros humus, 1850 m el., 15-v-1993 lot 03, Liebherr/Medeiros (CUIC, 1).

Etymology.

This cryptic sister sibling species of Mecyclothorax longidux is given the epithet brevidux -short leader-in reference to the foreshortened aedeagal median lobe apex (Figs 141 F–I).

Distribution and habitat.

Mecyclothorax brevidux is distributed in Kīpahulu Valley and on the Manawainui Planeze from 945-2045 m elevation (Fig. 142); a distribution allopatrically complementing that of Mecyclothorax longidux so that both species occupy most of Haleakalā’s windward forest. Most specimens of these beetles have been collected in moss, humus, or leaf litter in association with ‘ōhi‘a.