Mecyclothorax obscuricolor (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 : 40

Taxon classification Animalia Coleoptera Carabidae

(011) Mecyclothorax obscuricolor (Blackburn) Figs 18E, 20D, 21, 22 C–D, 23A

Cyclothorax obscuricolor Blackburn 1878a: 123; Blackburn and Sharp 1885: 215.

Thriscothorax obscuricolor , Sharp 1903: 266.

Mecyclothorax obscuricolor , Britton 1948b: 160.

Diagnosis.

Of species in this group with concolorous pronotal discs and margins, this species exhibits the smoothest elytral striae, with only minute punctures basally in striae 1-7 that cause slight irregularities of the strial surface (Fig. 20D). The pronotal median base is moderately depressed relative to the disc, with longitudinal punctures and wrinkles producing a rough surface. The dorsal surface bears well-developed microsculpture, an isodiametric mesh on the vertex, and transverse mesh on pronotal and elytral discs with sculpticell breadth 2 –3× length. Setal formula 2 1 2 1[sae]. Standardized body length 3.7-4.0 mm.

Identification

(n = 5). The eyes are little convex, ocular ratio = 1.36-1.42, and cover about ¾ of the ocular lobe; ocular lobe ratio = 0.71-0.82. The pronotal hind angles are obtuse, with the lateral margins divergent anteriorly from the angles. The pronotum is broad, MPW/PL = 1.31-1.33, with a moderately broad base, MPW/BPW = 1.40-1.52. The pronotal anterior transverse impression is deep, narrow, and crossed by deep wrinkles. The elytra are subquadrate with broad subangulate humeri, MEW/HuW = 1.78-1.95. Body coloration is quite uniform, with head and elytral disc rufobrunneous, and pronotal disc darker, rufopiceous. The legs are contrastedly paler, with metafemora rufoflavous with a piceous cloud over basal 1/3 of anterior surface, and the tibiae rufoflavous with a piceous cast, especially apically.

Male genitalia (n = 1). Aedeagal median lobe broad, robust, distance from parameral articulation to tip 3.2 × depth at midlength (Fig. 22C); apex broadly extended beyond ostial opening, the apical face flat; median lobe curved to the right, tip appearing flat in ventral view (Fig. 22D); internal sac covered with fine microspicules, brown, round flagellar plate evident inside midlength of lobe shaft (Fig. 22 C–D).

Female reproductive tract (n = 1). Bursa copulatrix broadly rounded, length 0.39 mm, breadth 0.34 mm (Fig. 23A); bursal walls thin, diaphanous; gonocoxite 1 with 3 apical fringe setae, the middle seta of series larger, 5 smaller setae on medial surface (Fig. 18E); gonocoxite 2 subtriangular, apex tightly rounded, base evenly extended from lateral margin, 2 lateral ensiform setae, the apical seta broader and longer, apical nematiform setae on medial surface at 0.75 × gonocoxite length.

Lectotype.

Female (BMNH) hereby designated, labeled: mounting platen with Blackburn Maui code ( Zimmerman 1957: 210), C. obscur. (on reverse) // Type // Hawaiian Is. Rev. T. Blackburn 1888-30 // LECTOTYPE Cyclothorax obscuricolor Blackburn J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat.

Mecyclothorax obscuricolor was collected by R.C.L. Perkins in four different collecting lots (Nos. 112, 371, 372, and 622) that were derived from elevations ranging 1200-1980 m ( Anonymous N D). Based upon the elevations and Perkin’s (1894) field notes, these localities spanned Olinda at lower elevations and Ukulele Camp and environs for the upper elevation localities (Fig. 21). No specific microhabitat may be ascribed to this species based on Perkins’ report ( Perkins 1896c), and the species has not been recollected since 1896.