Mecyclothorax interruptus 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 : 95-96

Taxon classification Animalia Coleoptera Carabidae

(035) Mecyclothorax interruptus Sharp Figs 45 O–P, 46F, 47F, 50 C–D, 51

Mecyclothorax interruptus Sharp 1903: 252; Britton 1948b: 163.

Mecyclothorax interruptus var. dubius Sharp 1903: 252; Britton 1948b: 163 (synonymy).

Diagnosis.

This species (Fig. 50D) can be diagnosed from its cryptic sibling species, Mecyclothorax foveolatus (Fig. 50B), using the criteria presented under that species (above). These two are the only Haleakalā species exhibiting: 1, strial fusion implicating striae 2-4 at the positions of the dorsal elytral setae; and 2, body sizes above 5 mm. Setal formula 2 2 2 2. Standardized body length 5.0-5.4 mm.

Identification

(n = 5). The eyes are moderately convex, ocular ratio = 1.37-1.50, and they cover much of the ocular lobe (Fig. 50D), ocular lobe ratio = 0.79-0.88. The pronotum is little constricted basally, MPW/BPW = 1.35-1.43, with the hind angle right to slightly obtuse, and the lateral margin briefly sinuate before the angle. The pronotal disc is smooth, glossy, with fine transverse wrinkles that extend little from the shallow, finely incised median longitudinal impression. The pronotal median base is covered with small punctures and fine longitudinal wrinkles. The elytra are subquadrate, with the humeri broadly rounded; MEW/HuW = 1.68-1.94. The dorsal body coloration is dark, with the vertex and pronotal disc rufopiceous, elytral disc rufobrunneous, and metafemur and metatibia flavous with a brunneous cast.

Male genitalia (n = 3). Aedeagal median lobe very slender, distance from parameral articulation to tip 6.8 × depth at midlength (Fig. 45O), shaft slightly curved basally, ventral margin dorsally recurved apically, apex with bluntly rounded dorsal projection, tip broadly tightly rounded, apical face convex; in ventral view median lobe slightly curved rightward toward apex, right margin slightly concave, left margin more incurved to rounded apex, blunt projection visible as apical expansion of rounded tip (Fig. 45P); internal sac without ornamentation.

Female reproductive tract (n = 1). Bursa copulatrix a narrow tube with apical lobe, medial bulge, and basal constriction (Fig. 46F), overall length 0.80 mm, apical breadth 0.17 mm, medial bulge breadth 0.23 mm; bursal walls translucent, thinly wrinkled; gonocoxite 1 with 2-3 apical fringe setae and 5-6 smaller setae on medial surface (Fig. 47F); gonocoxite 2 subtriangular, apex broad, base evenly extended laterally from curved lateral margin, 2 broad lateral ensiform setae, apical nematiform setae on medioventral surface at 0.73 × gonocoxite length.

Lectotypes.

For Mecyclothorax interruptus Sharp, female (BMNH) hereby designated, labeled: ♀ (in pencil) / Mecyclothorax / interruptus / Type D.S. / Haleakala / Perkins 597 (on obverse of mounting platen) // Type (round, red-margined label) // Hawaiian Is. / Perkins / 1904-336. / LECTOTYPE / Mecyclothorax / interruptus / Sharp / J.K. Liebherr 1998 (black-margined red label). For Mecyclothorax interruptus var. dubius Sharp, female (BMNH) hereby designated, labeled: M. in- / terruptus. var / dubius . D.S. / Haleakala / Perkins (on obverse of mounting platen), 623. (on reverse of platen) // Hawaiian Is. / Perkins / 1904-336. // LECTOTYPE / Mecyclothorax / interruptus var. dubius / Sharp / J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat.

Mecyclothorax interruptus is broadly distributed across the Waikamoi block of forest from 1170-1860 m elevation (Fig. 51). This species has been found by sifting ‘ōhi‘a leaf litter, searching under boards or logs on the ground, and by pyrethrin sampling moss-covered standing tree trunks and horizontal nurse logs.