Mecyclothorax iteratus 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 : 205-206

Taxon classification Animalia Coleoptera Carabidae

(085) Mecyclothorax iteratus Sharp Figs 102A, 103, 104A, 105A, 106

Mecyclothorax iteratus Sharp 1903: 250; Britton 1948b: 126.

Diagnosis.

The quadrisetose pronotum with deep transverse wrinkles crossing the disc and with the median base distinctly rugose (Fig. 102A) can diagnose this species from others in the group. The elytra are ovoid with narrow humeri, but the humeri are not as narrow relative to maximum elytral width as in the other two most similar species, Mecyclothorax reiteratus (Fig. 102B) and Mecyclothorax splendidus (Fig. 102C); MEW/HuW = 2.23-2.38 for this species versus values of 2.39-2.56 for measured individuals of the other two species. If the aedeagal median lobe projects even slightly from the abdominal apex of a male specimen, the broadened apex with dorsal projection (Fig. 103) can diagnose the specimen from those representing Mecyclothorax reiteratus (Fig. 107) or Mecyclothorax splendidus (Fig. 108). Setal formula 2 2 2 1[sae]. Standardized body length 4.7-6.0 mm.

Identification

(n = 5). The eyes are prominent and cover much of the ocular lobe, ocular lobe ratio = 0.90-0.93, but they are of variable convexity; ocular ratio = 1.54-1.74. The rugose pronotal surface involves deep, transverse discal wrinkles, a depressed, strigose median base with anastomosing punctures and elongate wrinkles and a deeply incised anterior transverse impression that is crossed by very distinct longitudinal wrinkles, the impression assuming a “zipperlike” appearance. Finally, the unique pattern of dorsal microsculpture can differentiate specimens of this species from Mecyclothorax reiteratus and Mecyclothorax splendidus ; 1, vertex glossy, an indistinct transverse mesh, sculpticell breadth 2 × length, in broad neck constriction; 2, pronotal disc glossy, indistinct transverse sculpticells restricted to the deep transverse wrinkles; 3, pronotal base with distinct transverse mesh, sculpticell breadth 2 –3× length, between punctures and wrinkles; 4, elytral disc with regular isodiametric mesh, a few cells of transverse orientation mixed in; and 5, elytral apex with regular isodiametric mesh.

Male genitalia (n = 16). Aedeagal median lobe gracile, distance from parameral articulation to tip 4.7 × depth at midlength (Fig. 103); apex dorsally curved beyond ostial opening, expanded dorsally as an acutely rounded tooth, the apical face slightly convex; median lobe curved rightward beyond ostial opening in ventral view, right margin narrowly concave, left margin sinuous-convex then concave-to join bluntly rounded tip (Fig. 103B); internal sac broad, with small dorsal ostial microtrichial patch on right side near base and ventral surface covered with diffuse field of melanic microspicules (Fig. 103C); flagellar plate substantial, elongate and robust, length 0.50 × parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix elongate, ovoid, with basal constriction distad the vagina, length 1.11 mm, maximum breadth 0.57 mm, basal constriction 0.31 mm (Fig. 104A); bursal wall translucent, thickly wrinkled; gonocoxite 1 with 3-4 apical fringe setae, a large seta at medioapical angle and 4-5 smaller setae on medial surface (Fig. 105A); gonocoxite 2 subtriangular, apex broad, base broadly, moderately extended laterally, 2 broad lateral ensiform setae with rounded apices, apical nematiform setae on medioventral surface at 0.70 × gonocoxite length.

Lectotype.

Female (BMNH) hereby designated, labeled: Mecyclothorax iteratus Type D.S. Haleakala Perkins 354 // Type // Hawaiian Is. R.C.L. Perkins 1904 -336. // LECTOTYPE Mecyclothorax iteratus Sharp J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat.

Mecyclothorax iteratus is broadly distributed around the entire forest belt of Haleakalā, with repeated collections in the Waikamoi forest, Hāna Bogs, Kīpahulu Valley, Manawainui Planeze and south face at Kahikinui (Fig. 106). Localities range 1210-2105 m elevation. Specimens have been collected on koa and ‘ōhi‘a trunks and associated mossmats, and from plant substrates including Cheirodendron ('ōlapa), Coprosma (pilo), Dubautia reticulata (kupaoa), Leptecophylla (pūkiawe), Myrsine (kolea), Rubus ( ‘ākala), Vaccinium ('ōhelo). It was even collected on Deschampsia nubigena (hairgrass) at Wai‘ele‘ele ( Gagné, BPBM).