Mecyclothorax montivagus (Blackburn)

Liebherr, James K., 2015, The Mecyclothorax beetles (Coleoptera, Carabidae, Moriomorphini) of Haleakala-, Maui: Keystone of a hyperdiverse Hawaiian radiation, ZooKeys 544, pp. 1-407 : 242-244

Taxon classification Animalia Coleoptera Carabidae

(098) Mecyclothorax montivagus (Blackburn) Figs 126B, 128B, 129B, 131 A–D, 132

Cyclothorax montivagus Blackburn 1878a: 122; Blackburn and Sharp 1885: 214.

Mecyclothorax montivagus , Sharp 1903: 253; Britton 1948b: 133.

Olisthopus insularis Motschulsky, Karsch 1881: 1 (misidentification).

Diagnosis.

This is one of two Haleakalā species (Fig. 126 B–C) in this group that exhibit the full complement of supraorbital, pronotal, and dorsal and apical/subapical elytral setae; setal formula 2 2 2 2. However Mecyclothorax montivagus beetles are of moderate to large size for Hawaiian Mecyclothorax -standardized body length 4.9-6.9 mm-in contrast to those of Mecyclothorax micans ; standardized body length 3.6-4.3 mm. If a qualitative character is desired to separate the species, one may use the presence of the parascutellar seta in individuals of this species, and the lack thereof in individuals of Mecyclothorax micans .

Identification

(n = 5). The frontal grooves are broad medially, with a slight hitch laterad near midlength, the groove terminated at a fine carina mesad the anterior supraorbital seta. The head capsule is transversely concave between the hind eye margins, resulting in a broad shallow neck that is visible in dorsal view. The pronotum is transverse, MPW/PL = 1.28-1.35, with the lateral margins sinuate for only a very short distance anterad the hardly projected hind angles, the angles themselves obtuse and appearing as little more than denticles at the terminus of the lateral marginal bead posterad the laterobasal depressions; MPW/BPW = 1.47-1.57. The median pronotal base is densely punctate with elongate wrinkles lining the juncture of the base and disc. The pronotal anterior transverse impression is smooth, shallow, with the anterior callosity upraised, flat to slightly convex, and smooth. The elytra are subquadrate with rounded lateral margins posterad the broadly rounded humeri; MEW/HuW = 1.97-2.05. Discal striae 1-4 are impressed, distinctly punctate, stria 5-6 are progressively shallower, with punctures more isolated along their length, and stria 7 is absent. The mesepisternum is less punctate than in Mecyclothorax rex , with ~9 minute punctures in 2 rows. The metathoracic flight wings are the least reduced-though still vestigial-of any Hawaiian Mecyclothorax ; flight wing vestigium an apically narrowed strap, 3.3 × long as broad, remnant C, R, M, and Cu veins present, and the strap extended for 0.3 × its length beyond the hind margin of the metanotum. Microsculpture is reduced: 1, vertex and pronotal disc with obsolete transverse mesh; 2, pronotal median base with an obsolete transversely stretched isodiametric mesh; 3, elytral disc with obsolete elongate transverse mesh, apex glossy; 4, surfaces of metasternum and laterobasal abdominal ventrites mostly glossy, shallow transverse-mesh microsculpture over portions of cuticle.

Male genitalia (n = 8). Aedeagal median lobe large but gracile, distance from parameral articulation to top 4.5 –4.9× depth at midlength (Fig. 131A, C–D); apex broadly extended for about 1.6 × depth beyond ostial opening, tip variously convex dorsally (Fig. 131A), expanded dorsoventrally (Fig. 131C), or nearly parallel and narrowed to rounded tip (Fig. 131D); median lobe straight along median shaft in ventral view, apex slightly curved rightward with right margin concave and left margin sinuous before bluntly rounded tip (Fig. 131B); internal sac broad, with dorsal ostial microtrichial patch near base on right side, and ovoid ventral ostial microtrichial patch on left side further out on sac (Fig. 131D); flagellar plate moderately large, length 0.48 × parameral articulation-tip distance.

Female reproductive tract (n = 3). Bursa copulatrix columnar with rounded apex, length 1.65 mm, breadth 0.80 mm, basal constriction at vagina 0.45 mm broad (Fig. 128B); bursal walls translucent with thick wrinkles; gonocoxite 1 with 4 apical fringe setae, a curved seta at apicomedial angle and ~7 setae on medial surface (Fig. 129B); gonocoxite 2 broadly subtriangular, apex broad, basally extended by a long panhandle with curved terminus, 2 broad lateral ensiform setae, apical nematiform setae on medioventral surface at 0.65 × gonocoxite length.

Lectotype.

Male (BPBM) hereby designated, dissected, and labeled: mounting platen with Blackburn Maui label ( Zimmerman 1957: 210), 5 mont (on reverse) // Type // Sandwich Is. 80-6 // LECTOTYPE Cyclothorax montivagus Blackburn J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat.

Mecyclothorax montivagus is a species of Deschampsia grassland found along the upper Kula face and in Haleakalā Crater (Fig. 132). Present day elevations range 2134-2800 m elevation, though historical records from Finsch ( Karsch 1881) and Perkins (lot 112; Anonymous N D) were from Olinda near 1210 m elevation. Specimens have also been found in leaf litter under Sophora chrysophylla ( māmane) at 2750 m elevation, and under rocks in drier, less vegetated situations from 1830-2440 m elevation.