Mecyclothorax cymindicus 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 : 66-67

Taxon classification Animalia Coleoptera Carabidae

(023) Mecyclothorax cymindicus Sharp Figs 30F, 34M, 37B, 38A, 40

Mecyclothorax cymindicus Sharp 1903: 248; Britton 1948b: 164.

Diagnosis.

Along with Mecyclothorax cymindulus , the smallest-bodied beetles in the group (Fig. 38 A–B) excepting the smallest individuals of Mecyclothorax antaeus (Fig. 33D); standardized body length for this species 4.1-4.7 mm. This and Mecyclothorax cymindulus are also the most narrow-bodied species, with subquadrate elytra and subangulate, laterally extended humeri (Figs 38 A–B). This species deviates from Mecyclothorax cymindulus by the distinctly punctate discal elytral striae, the punctures in basal portions of striae 1-5 expanding strial breadth, and by the less transverse microsculpture; The elytral sutural interval is covered with isodiametric microsculpture, with the lateral intervals bearing a transverse mesh, sculpticell breadth 3 –4× length, versus the transverse mesh on the sutural interval and transverse lines laterally observed in individuals of Mecyclothorax cymindulus . The eyes also tend to be more convex in this species-ocular ratio = 1.41-1.45-versus the ocular ratio = 1.34-1.43 of Mecyclothorax cymindulus . Setal formula 2 2 2 2.

Identification

(n = 5). The pronotum is little transverse, MPW/PL = 1.17-1.22, and the pronotal hind angles are acute and moderately projected, with the pronotal lateral margins slightly convergent anterad the angles; MPW/BPW = 1.36-1.54. The elytral humeral angles are defined by a hitch in the recurved basal groove at its juncture with the lateral marginal depression; MEW/HuW = 1.83-1.95. The vertex is covered with a transverse mesh, sculpticell breadth 2 × length; pronotal disc with transverse mesh, sculpticell breadth 3 –4× length, and pronotal base with distinct isodiametric sculpticells medially and a transverse mesh laterally.

Male genitalia (n = 1). Aedeagal median lobe gracile, distance from parameral articulation to tip 3.6 × depth at midlength (Fig. 34M); apex moderately extended beyond ostial opening, apical face flat, tip rounded at juncture of apical face and ventral margin; internal sac with sclerotized dorsal microtrichial patch (based on distal position in uneverted specimen); flagellar plate length 0.47 × parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar with rounded apex, length 1.03 mm, breadth 0.29 mm (Fig. 30F); bursal walls translucent, thickly wrinkled; gonocoxite 1 with 4 apical fringe setae and 7 smaller setae on medial surface (Fig. 37B); gonocoxite 2 narrowly subtriangular with broad apex, tip tightly rounded, 2 lateral ensiform setae, the apical seta broader and longer, apical nematiform setae on medioventral surface at 0.77 × gonocoxite length.

Lectotype.

Female (BMNH) hereby designated, labeled: Mecyclothorax cymindicus Type D.S. Haleakala Perkins 680 // Type // Hawaiian Is. Perkins 1904-336 // LECTOTYPE Mecyclothorax cymindicus Sharp J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat.

Mecyclothorax cymindicus is geographically restricted to the Waikamoi area (Fig. 40), with localities ranging 1210-1740 m elevation. Perkins’ collections were made in the vicinity of Ukukule Camp along the then leeward edge of the Koa- ‘Ōhi‘a Mesic Forest, with more recent records from the Honomanu drainage to the east and Waikamoi Gulch from 1210-1435 m elevation. Specimens have been recorded in association with ‘ōhi‘a trunks, logs, or leaf litter, and Cibotium ( hāpu‘u).