Mecyclothorax aeneus Sharp

Liebherr, James K., 2015, The Mecyclothorax beetles (Coleoptera, Carabidae, Moriomorphini) of Haleakala-, Maui: Keystone of a hyperdiverse Hawaiian radiation, ZooKeys 544, pp. 1-407 : 61-62

Taxon classification Animalia Coleoptera Carabidae

(021) Mecyclothorax aeneus Sharp Figs 30D, 31D, 33C, 36

Mecyclothorax aeneus Sharp 1903: 255; Britton 1948b: 164.

Diagnosis.

The narrow body and moderately convex elytral intervals with nearly smooth striae set this species apart. Individuals of this species can be diagnosed by the narrow pronotum–MPW /PL = 1.15 –1.19– with its lateral margins convergent for 0.1 × the pronotal length anterad the acute, projected hind angles (Fig. 33C). The elytra are narrowly ellipsoid, with distinctly recurved basal grooves leading to proximate, subangulate humeri; MEW/HuW = 2.04-2.15. The elytral disc is rufobrunneous, with a cupreous reflection enhanced by a distinct granulate isodiametric mesh. At the elytral apex, the 8th interval is more convex than the fused apical portion of intervals 5 + 7. Setal formula 2 2 2 2. Standardized body length 5.7-5.8 mm for specimens available to the author, though Britton (1948b) listed the size range as 4.8-5.8 mm.

Identification

(n = 2). The eyes are moderately convex, ocular ratio = 1.42, covering ¾ of the protruded ocular lobe, ocular lobe ratio = 0.76. There is a deep carinate groove at the juncture of lobe and gena. The pronotal median base is depressed relative to the disc, and irregularly covered with fine punctures, longitudinal wrinkles lining the juncture of base and disc. The pronotal anterior transverse impression is shallow and broad, not incised, and crossed by dense, deep longitudinal wrinkles that extend across the anterior callosity. The pronotal laterobasal depressions are broad and smooth, with a well-developed median tubercle. The mesepisternum bears ~16 punctures in 2-3 rows. Microsculpture is well developed, with the vertex covered by an isodiametric mesh in transverse rows, and the pronotal base covered with mixture of granulate isodiametric and transverse sculpticells.

Female reproductive tract (n = 1). Bursa copulatrix columnar with rounded apex, length 1.14 mm, breadth 0.39 mm, base as broad as vagina (Fig. 30D); bursal walls translucent with thick wrinkles in basal half, more transparent and little wrinkled apically; gonocoxite 1 with 3-4 apical fringe setae and 8-9 small setae on medial surface (Fig. 31D); gonocoxite 2 narrowly subtriangular with broad apex, tightly rounded tip, 2 lateral ensiform setae with apical seta broader and longer, apical nematiform setae on medioventral surface at 0.72 × gonocoxite length.

Lectotype.

Male (BMNH) hereby designated, labeled: Thriscothorax aeneus D.S. Type Haleakala Perkins 383 // Type // Hawaiian Is. Perkins 1904-336 // LECTOTYPE Mecyclothorax aeneus Sharp J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat.

Mecyclothorax aeneus is a species of the mesic Waikamoi forests (Fig. 36). In 1894 Perkins collected two specimens near the leeward forest edge at Ukulele Camp, with two more recently collected specimens from 1700-1850 m elevation in the Honomanu drainage complementing the original type series. The two recent collections were made from moss and humus adhering to ‘ōhi‘a trunks.