Mecyclothorax sobrinus 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 : 109-110

Taxon classification Animalia Coleoptera Carabidae

(042) Mecyclothorax sobrinus Sharp Figs 54E, 55E, 57C, 58 D–F, 59

Mecyclothorax sobrinus Sharp 1903: 253; Britton 1948b: 143.

Diagnosis.

Individuals of this species exhibit overlapping head, prothoracic, and elytral ratios and standardized body length-5.5-6.6 mm-with Mecyclothorax consobrinus , reducing any diagnosis of the two species to qualitative characters associated with elytral setation and punctation, and cuticular microsculpture. The discal elytral striae are deeper and of more uniform depth in this species than in Mecyclothorax consobrinus . Striae 1-6 are closely punctured in the basal 2/3 of their length. The setal impressions associated with the two dorsal elytral setae are shallower and less broad than seen in Mecyclothorax consobrinus , depressing interval 3 plus less than half of interval 4. Also, the apical depression associated with interval 7 is shallower and more regularly depressed among individuals of this species. Finally, the microsculpture is less upraised overall: 1, vertex with well-developed isodiametric sculpticells in transverse rows; 2, pronotal disc with well-developed slightly transversely stretched mesh, the median base covered with a mixture of isodiametric and transverse sculpticells; 3, elytral disc with a transverse mesh, sculpticell breadth 2 × length, apex with mesh more transverse, breadth 2 –3× length. Also, no individuals representing this species have been observed to have more than two dorsal elytral setae. Setal formula 2 2 2 2.

Identification

(n = 5). Although the ratios overlap with Mecyclothorax consobrinus , eyes tend to be less developed in individuals of this species; ocular ratio = 1.37-1.46 versus 1.41-1.46 in Mecyclothorax consobrinus , ocular lobe ratio = 0.71-0.77 versus 0.74-0.76. The pronotal median base is relatively smooth, with only sparse fine punctures and a few longitudinal wrinkles. The pronotal lateral marginal depression is only slightly broader at the front angles, the angles tightly rounded. The mesepisternum is moderately punctate, with ~9 punctures in 1-2 longitudinal rows. Finally, the male median aedeagal lobe has a less developed dorsal projection and narrower, more rounded apex (Fig. 58 D–F) than that of the adelphotaxon’s males.

Male genitalia (n = 2). Aedeagal median lobe (Fig. 58D) a slightly less exaggerated version than that characterizing Mecyclothorax consobrinus (Fig. 58A), distance from parameral articulation to tip 4.2 × depth at midlength, apex broadly rounded in company with blunt, broad dorsal projection, the dorsal projection varying in curvature and apical shape (Fig. 58 D–E), apex of median lobe curved rightward, dorsal projection curved leftward (Fig. 58F).

Female reproductive tract (n = 1). Bursa copulatrix broad, columnar apex rounded, ventral surface dorsad bursa copulatrix-common oviduct juncture with brownish coloration, lightly sclerotized, bursal length 1.0 mm, breadth 0.51 mm (Fig. 54E); bursal walls translucent with thick wrinkles outside area of sclerotization; gonocoxite 1 with 3-4 apical fringe setae, thicker apicomedial seta present at apical angle, 7-8 smaller setae basally along median margin (Fig. 55E); gonocoxite 2 narrowly subtriangular with tightly rounded apex, base broadly extended laterally, 2 lateral ensiform setae, apical nematiform setae on medioventral surface at 0.71 × gonocoxite length.

Lectotype.

Male (BMNH) hereby designated, labeled: Mecyclothorax sobrinus Type D.S. Haleakala Perkins 350 // Type // Hawaiian Is. Perkins 1904-336. // Haleakala Maui 4500 ft. Perkins 28 III 1894 // LECTOTYPE Mecyclothorax sobrinus Sharp J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat.

Mecyclothorax sobrinus inhabits mesic forest west of Waikamoi Gulch (Fig. 59) from 1280-1980 m elevation. E.C. Zimmerman collected two specimens by beating at 6000-6500 ft. elevation on the NW upper slope; these specimens representing outliers to modern collections in the Koa- ‘Ōhi‘a Mesic Forest near Ukulele Pipeline. Forest-inhabiting specimens have been found in sifted litter associated with ‘ōhi‘a and Cibotium ( hāpu‘u) tree fern. The largest collections have come from yellow-pan traps set in ecotone forest situations (vi-viii-2006, L. Leblanc, UHIM).