Mecyclothorax scaritoides (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 : 187-188

Taxon classification Animalia Coleoptera Carabidae

(078) Mecyclothorax scaritoides (Blackburn) Figs 95C, 96C, 97B, 98B, 99

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

Metrothorax scaritoides , Sharp 1903: 272.

Mecyclothorax scaritoides , Britton 1948b: 120.

Acupalpus biseriatus Karsch 1881: 2 (new synonymy).

Diagnosis.

This species (Fig. 95C) shares a glabrous pronotum with three other members of the Mecyclothorax scaritoides group: Mecyclothorax molops (Fig. 95A), Mecyclothorax macrops (Fig. 95B), and Mecyclothorax scarites (Fig. 95D). Among them this species deviates by exhibiting two supraorbital setae; setal formula 2 0 2 0. The discal elytral striae are more distinctly punctate in this species, with both the sutural stria and parascutellar striole punctate-in some instances very indistinctly so-to the elytral basal groove. In beetles of the most similar species, Mecyclothorax scarites , the sutural stria is continued to the basal groove, but it is smooth, and the parascutellar striole is little impressed with the punctures taking the form of elongate irregularities. The elytra are also more broadly subellipsoid in this species, with the tightly rounded to subangulate humeri more proximate; MEW/HuW = 2.04-2.15 versus values of 1.93-2.0 for specimens of Mecyclothorax scarites . Standardized body length 5.0-5.8 mm.

Identification

(n = 5). The eyes are convex and large, ocular ratio = 1.50-1.53, ocular lobe ratio = 0.81-0.85. The pronotum is moderately transverse, MPW/PL = 1.16-1.25, with basally sinuate lateral margin, the hind angle obtuse with apex pointed. The pronotal median base is coplanar with the disc medially, depressed laterally, with ~20 small, isolated punctures each side. The median longitudinal impression is very shallow, traceable to obsolete, and the anterior transverse impression is broad and shallow medially, narrow and finely incised laterally. Microsculpture in this species deviates from other similar species in that the elytral disc is covered with a distinct isodiametric mesh that incorporates transverse sculpticells, breadth 2 × length, and the elytral apex is covered with an isodiametric mesh in transverse rows. Microsculpture otherwise present includes: 1, vertex with obsolete transverse mesh, sculpticell breadth 2 × length; 2, pronotal disc with obsolete transverse mesh, sculpticell breadth 3 –4× length, most parts of cuticle glossy; 3, pronotal median base glossy, with indistinct transverse cells laterally; and 4, metasternum with obsolete transverse mesh, surface glossy.

Male genitalia (n = 1). Aedeagal median lobe gracile, distance from parameral articulation to tip 4.4 × depth at midlength (Fig. 96C); apex broadly expanded on dorsal surface, slightly expanded ventrally, tip broadly rounded; internal sac appearing unornamented (uneverted specimen); flagellar plate moderately long, length 0.42 × parameral articulation-tip distance (estimated from shadow of sclerotized plate, Fig. 96C).

Female reproductive tract (n = 1). Bursa copulatrix columnar with narrower apex, broader base, length 0.68 mm, apical breadth 0.15 mm, basal breadth 0.38 mm (Fig. 97B); bursal walls translucent, thinly wrinkled; gonocoxite 1 with 4-5 apical fringe setae with the medial seta smaller (Fig. 98B), a thick, curved seta at medioapical angle and 5-6 smaller setae along medial surface; gonocoxite 2 falcate with acuminate tip, base broadly extended laterally with curved terminus, 2 broad lateral ensiform setae, apical nematiform setae on medioventral surface at 0.76 × gonocoxite length.

Lectotypes.

For Cyclothorax scaritoides , female (BMNH) hereby designated, labeled: mounting platen with Blackburn Maui label ( Zimmerman 1957: 210), scaritoid (on reverse) // Type // Hawaiian Is. Rev. T. Blackburn 1888-30. // LECTOTYPE Cyclothorax scaritoides Blackburn J.K. Liebherr 1998 (black-margined red label). For Acupalpus biseriatus , female (MNHU) hereby designated, labeled: LECTOTYPE Acupalpus biseriatus Karsch det. J.K. Liebherr 2000 (black-margined red label) // Mecyclothorax scaritoides (Sharp) det. J.K. Liebherr 2000.

Distribution and habitat.

Mecyclothorax scaritoides was historically distributed along the leeward edge of the Waikamoi forest (Fig. 99). During the 1870s, Blackburn (BMNH) and Finsch (MNHU) collected specimens at elevations from 1085-1210 m near Olinda. By the time Perkins arrived in 1894, his collections were restricted to elevations of 1210-1525 m in the vicinity of Ukulele Camp. Perkins collected 187 specimens from 1894 to 1902, and nobody has seen this species in nature since. However, a closely related species, Mecyclothorax scarites (see below) was collected in the vicinity of Olinda from 1926-1935.