Mecyclothorax cordaticollis (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 : 140-141

Taxon classification Animalia Coleoptera Carabidae

(055) Mecyclothorax cordaticollis (Blackburn) Figs 62I, 73B, 74B, 76 A–B, 77

Cyclothorax cordaticollis Blackburn 1878b: 156; Blackburn and Sharp 1885: 215.

Thriscothorax cordaticollis , Sharp 1903: 259.

Mecyclothorax cordaticollis , Britton 1948b: 148.

Thriscothorax modestus Sharp 1903: 259; Britton 1948b: 148 (synonymy).

Diagnosis.

This species (Fig. 73B), Mecyclothorax cordaticollaris (Fig. 73C), and Mecyclothorax subconstrictus (Fig. 73D) are the only three Mecyclothorax ovipennis group species to exhibit the 2 1 1 0 setal formula (at least for some of the individuals of the latter species). Mecyclothorax cordaticollis and Mecyclothorax subconstrictus share shallow, minutely punctate discal elytral intervals and associated slightly convex intervals, plus a narrowly constricted pronotum; MPW/BPW = 1.55-1.61 in this species. The discal elytral striae are much more punctate in Mecyclothorax cordaticollaris , and the associated intervals are much more convex. Mecyclothorax cordaticollis and Mecyclothorax subconstrictus can be definitively diagnosed using dorsal microsculpture. The pronotal disc of Mecyclothorax cordaticollis bears transverse-mesh microsculpture, sculpticell breadth 2 –3× length, and the elytral disc is covered with a transverse mesh, sculpticell breadth 2 –4× length. For Mecyclothorax subconstrictus , the pronotal disc is glossy medially, and laterally covered with an obsolete transverse mesh, whereas the elytral disc bears a mixture of isodiametric and transverse sculpticells. Standardized body length 3.6-4.1 mm.

Identification

(n = 4). The eyes are moderately convex, ocular ratio = 1.42-1.49, but they cover much of the ocular lobe, ocular lobe ratio = 0.81-0.86. The pronotal lateral marginal depression is narrow, the edge upturned anterad lateral seta, slightly broader near front angle, and thin and beadlike along basal sinuation. The pronotal apical width is greater than the basal width; APW/BPW = 1.01-1.06. The elytra are subquadrate, with the tightly rounded humeral angles connected medially to only slightly recurved basal grooves. Though all the striae are shallow, they are all of similar depth on the elytral apex.

Male genitalia (n = 1). Aedeagal median lobe short, squat, distance between parameral articulation and tip 2.5 × depth at midlength (Fig. 76A); apex extended beyond ostial opening equal to its depth, tip broadly rounded; median lobe curved rightward apically in ventral view (Fig. 76B), right margin slightly concave near tip, left margin broadly convex; internal sac with ventral ostial microtrichial patch indicated in uneverted specimen, shadow of flagellar plate also visible, the plate quite elongate, length 0.67 × parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar, length 0.84 mm, breadth 0.34-0.38 mm (Fig. 62I); bursal walls translucent, thinly wrinkled; gonocoxite 1 with 3 apical fringe setae, middle seta larger, 1 small seta at apicomedial angle, and 4-5 setae on medial surface (Fig. 74B); gonocoxite 2 broadly subtriangular, apex tightly rounded, base moderately extended laterally, 2 short lateral ensiform setae, apical nematiform setae on medial surface at 0.75 × gonocoxite length.

Lectotypes.

For Cyclothorax cordaticollis , female (BMMH) hereby designated, labeled: mounting platen with Blackburn Maui label ( Zimmerman 1957: 210), cord (on reverse) // Type // Hawaiian Is. Rev. T. Blackburn 1888-30. // LECTOTYPE Cyclothorax cordaticollis Blackburn J.K. Liebherr 1998 (black-margined red label). For Thriscothorax modestus , male (BMNH) hereby designated, labeled: Thriscothorax modestus Type D.S. Haleakala 350 // Type // Hawaiian Is. Perkins 1904-336. // LECTOTYPE Thriscothorax modestus J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat.

Mecyclothorax cordaticollis is known from only three definitive localities in the leeward forests west of Waikamoi Gulch (Fig. 77). Ukulele Camp (Site) is the most likely locality given Perkins’ (1894, 1896b) field notes. There no collecting records since Perkins collected two specimens in 1902.