Mecyclothorax strigosus, Liebherr, James K., 2015

Liebherr, James K., 2015, The Mecyclothorax beetles (Coleoptera, Carabidae, Moriomorphini) of Haleakala-, Maui: Keystone of a hyperdiverse Hawaiian radiation, ZooKeys 544, pp. 1-407 : 120-122

Taxon classification Animalia Coleoptera Carabidae

(046) Mecyclothorax strigosus sp. n. Figs 60D, 62A, 63A, 64

Diagnosis.

This species (Fig. 60D) plus Mecyclothorax ovipennis (Fig. 65A) and Mecyclothorax flaviventris (Fig. 68C) comprise the three species in this group with the largest, most convex eyes; ocular ratio = 1.55-1.57 in this species. Of these, both Mecyclothorax ovipennis and this species are characterized by impunctate discal striae 1-4. This species (Fig. 60D) can be told from Mecyclothorax ovipennis (Fig. 65A) by the narrower body with more basally constricted pronotum, MPW/BPW = 1.56-1.67, and more narrowly ellipsoid elytra. Moreover, this is the only one of the three with glabrous hind pronotal angles, and without any apical elytral setae; setal formula 2 1 2 0. Standardized body length 4.3-4.7 mm.

Description

(n = 2). Head capsule with frontal grooves broad near clypeus, lateral carina to anterior supraorbital seta; dorsal surface of neck flat; ocular lobe distinctly protruded from gena, eyes large, ocular lobe ratio = 0.79-0.80; labral anterior margin very shallowly emarginate medially; antennae filiform, antennomeres 2-3 with sparse pelage of short setae; mentum tooth with sides acute, apex broadly rounded. Pronotum appearing elongate, MPW/PL = 1.11-1.18; hind angle right, lateral margin straight, subparallel to slightly convergent anterad hind angle; median base only slightly depressed, ~15 densely distributed punctures each side extended to laterobasal depression; basal margin nearly straight across base; median longitudinal impression very shallow, finely incised; anterior transverse impression very shallow, broad, crossed by longitudinal wrinkles; anterior callosity nearly flat, crossed by indistinct wrinkles; front angles not projected, tightly rounded; pronotal apical width greater than basal width, APW/BPW = 1.09-1.16; lateral marginal depression very narrow throughout length, edge tightly upturned; laterobasal depression depressed, punctate surface continuous with median base. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process with narrow median impression, lateral margins broadly beaded between coxae. Elytra with disc flat, sides steeply sloped to depressed lateral margins and apex; basal groove briefly, distinctly recurved to angulate humerus; parascutellar seta present; parascutellar striole with 4-5 punctures, shallow, continuous between punctures; sutural interval more convex than intervals 2-4, but sutural juncture still depressed; sutural stria shallow, with minute punctulae basally, slightly deeper and more well defined than 2nd stria on disc, the two of subequal depth apically; discal striae 2-4 shallow, smooth, striae 5-6 obsolete but traceable, stria 7 absent; discal intervals 2-4 only slightly convex to nearly flat, lateral intervals flat; 8th interval of similar convexity to fused apical portion of striae 5 + 7; 2 dorsal elytral setae at 0.30 –0.31× and 0.61 –0.66× elytral length, setal impressions very small, spanning 1/3 of interval 3; lateral elytral setae arranged in anterior series of 7 setae, and posterior series of 6 setae; elytral marginal depression narrow, margin upturned, beaded only at subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~7 punctures in 2 rows; metepisternal width to length ratio = 0.72; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1-3, lateral depressions on ventrites 3-6; suture between ventrites 2 and 3 reduced laterally, effaced; apical female ventrite with 4 equally spaced setae plus median trapezoid of 4 setae, the basal pair longer. Legs-metatarsomere 1/metatibial length ratio = 0.18; metatarsomere 4 length along outer lobe 1.25 × medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, shallow, median area broad. Microsculpture of vertex and pronotal disc a transverse mesh, sculpticell breadth 2 –3× length; pronotal median base with transverse mesh, sculpticell breadth 2 × length, between punctures; elytral disc and apex with isodiametric to transverse sculpticells, sculpticell breadth 2 × length, in transverse rows; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomere 1-3 flavous, 4-11 darker, more brunneous; pronotal disc rufobrunneous with piceous cast, the lateral margins moderately, and base and apex broadly, rufoflavous; proepipleuron rufoflavous, proepisternum rufobrunneous with piceous cast; elytral disc dark, rufobrunneous to rufopiceous; sutural interval rufobrunneous basally, flavous in apical 1/3; elytral intervals 7-9 slightly paler than disc, rufoflavous basally, flavous apically; elytral epipleuron flavous, metepisternum rufobrunneous with piceous cast; abdomen with ventrite 1 (plus metepimeron) rufobrunneous, ventrites 2-3 and middle of ventrites 4-5 rufopiceous; abdominal apical ventrite with apical 2/3 flavous; metafemur flavous; metatibia flavous with brunneous cast.

Female reproductive tract (n = 1). Bursa copulatrix columnar with apical expansion, length 1.0 mm, apical expansion breadth 0.46 mm, basal breadth 0.34 mm (Fig. 62A); bursal shaft translucent, thinly wrinkled, apex more transparent, less wrinkled; gonocoxite 1 with 3 apical fringe setae, the middle seta more robust, a larger seta at apicomedial angle and 12-13 smaller setae basally on medial surface (Fig. 63A); gonocoxite 2 falcate with subacuminate apex, base extended laterally as sinuous panhandle, 2 lateral ensiform setae, apical nematiform setae on medial surface at 0.75 × gonocoxite length.

Holotype.

Female (CUIC) labeled: HI: Maui Haleakala N.P. / Kipahulu west rim ESE / Kuiki, sift humus ex ohia / 15-V-1993 lot 02 / el. 1850 m / J.K. Liebherr & / A.C. Medeiros / Collectors // 2 // HOLOTYPE / Mecyclothorax / strigosus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratype.

Female (CUIC) dissected, with same label as holotype except “1” instead of “2.”

Etymology.

The Latin adjectival strigosus , meaning thin, signifies the narrow body shape characteristic of this species.

Distribution and habitat.

Mecyclothorax strigosus has only been encountered in ‘Ōhi‘a Montane Wet Forest ESE of Kuiki at 1850 m elevation (Fig. 64). The two specimens were found in a litter sample sifted from humus surrounding the bases of large ‘ōhi‘a trees. The forest also included Cheirodendron ('ōlapa) and Leptecophylla tameiameiae (pūkiawe). The sample containing specimens of Mecyclothorax strigosus also included specimens of Mecyclothorax antaeus , Mecyclothorax consanguineus , Mecyclothorax mauiae , Mecyclothorax ovipennis , and Mecyclothorax pau .