Mecyclothorax notobscuricornis, 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 : 28

Taxon classification Animalia Coleoptera Carabidae

(005) Mecyclothorax notobscuricornis sp. n. Figs 15B, 16 C–D, 17B, 18B, 19

Diagnosis.

Among the pale-margined members of this species group, Mecyclothorax notobscuricornis (Fig. 15B) stands out due to the basally constricted pronotum; MPW/BPW = 1.57-1.61. This is also the largest-bodied species in the group, with standardized body length 3.6-4.3 mm. Like Mecyclothorax daptinus , this species is characterized by well-developed forebody microsculpture and glossy elytra. The vertex is covered with well-developed isodiametric and transverse-mesh microsculpture, the pronotal disc by a well-developed transverse mesh, sculpticell breadth 2 –3× length, whereas the discal elytral intervals are glossy, their surface covered with reduced transverse lines. Setal formula 2 1 2 1[sae].

Description

(n = 4). Head capsule with frontal grooves broad near clypeus, an associated lateral carina extended to anterior supraorbital seta; dorsal impression of neck flat to slightly concave; labral anterior margin broadly, shallowly emarginate; antennomeres 2-3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum with lateral setae present, basal absent; hind angle obtuse to right, to slightly acute, margin rounded posterad angle; lateral margin subparallel to convergent anterad hind angle; median base depressed relative to disc, with fine longitudinal wrinkles; basal margin straight medially, expanded posterad laterobasal depressions; median longitudinal impression moderately deep at midlength, finely incised, extended onto median base; anterior transverse impression broad, shallow, crossed with longitudinal wrinkles, lined with granulate isodiametric microsculpture; anterior callosity slightly convex; front angles slightly projected, tightly rounded, more distant than hind angles, APW/BPW = 1.06-1.12; lateral marginal depression narrow throughout length, edge reflexed, beadlike margin only anterad and posterad hind angle; laterobasal depression smooth, continuous with lateral depression. Proepisternum with smooth hind marginal groove; prosternal process medially depressed, sides broadly upraised laterally. Elytra subovoid, disc moderately convex, lateral margins more so; basal groove distinctly recurved to subangulate humeral angle, MEW/HuW = 1.95-2.07; parascutellar seta present; parascutellar striole with 3-5 punctures, deep, continuous; sutural interval more convex than lateral intervals, sutural juncture elevated; sutural and 2nd striae of subequal depth from base to apex; all striae deep, associated intervals convex; 7th and 8th interval similarly convex near apex; 2 dorsal elytral setae, anterior at 0.29 ×, and posterior at 0.58 –0.61× elytral length, setae situated in depressions spanning 2/3 of interval 3; subapical seta present, apical seta absent; lateral elytral setae arranged in anterior series of 7 setae, posterior series of 5(6) setae; elytral marginal depression broadly reflexed, translucent posterad humerus, narrowed apically to beadlike margin anterad subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with 6 shallow punctures, most in 1 row; metepisternal width to length ratio = 0.82; metepisternum/metepimeron suture distinct. Abdomen with irregular wrinkles laterally on ventrites 1-5; suture between ventrites 2 and 3 reduced, effaced laterally; apical male ventrite with 2 apical setae, apical female ventrite with 4 equally spaced setae plus a median trapezoid of 4 small setae. Legs-metatarsomere 1/metatibial length ratio = 0.19; metatarsomere 4 length along outer lobe 1.25 × medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, lateral, median area broad. Microsculpture of vertex well-developed isodiametric mesh in rows; pronotal disc with well-developed transverse mesh, sculpticell breadth 2 –3× length; pronotal median base with upraised isodiametric and transverse mesh, transverse sculpticell breadth 2 × length; elytral discal surface glossy, with reduced transverse lines; elytral apex with shallow transverse mesh and lines; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomere 1 flavous, antennomeres 2-3 rufous, 4-11 rufobrunneous; pronotal disc rufopiceous, lateral margins flavous, apex and base rufoflavous; proepipleuron rufoflavous, proepisternum rufobrunneous; elytral disc rufopiceous on intervals 2-5 to 2-6, base of interval 6 flavous; sutural interval rufobrunneous basally, rufoflavous apically; elytral intervals 7-9 pale, flavous, apex flavous to apical juncture of intervals 3 and 4; elytral epipleuron flavous dorsally, rufoflavous ventrally, metepisternum rufopiceous; abdominal ventrites 1-5 rufopiceous medially, 3-6 flavous laterally; apical half of apical ventrite 6 pale, flavous; metafemur flavous; metatibia rufoflavous with piceous cast.

Male genitalia (n = 1). Aedeagal median lobe broad, robust, distance from parameral articulation to tip 2.5 × depth at midlength, apex broadly rounded and little extended beyond ostial opening (Fig. 16C); slightly curved to the right, the tip broadly rounded in ventral view (Fig. 16D); internal sac unornamented, large flagellar plate evident inside dorsal surface of median lobe dorsad parameral articulation (Fig. 11C).

Female reproductive tract (n = 1). Bursa copulatrix elongate, broad with rounded apex, length 0.57 mm, breadth at bursal-vaginal juncture 0.23 mm, maximum vagina breadth 0.35 mm (Fig. 17B); bursal walls translucent, thinly wrinkled; gonocoxite 1 with 3 apical fringe setae, 5 setae on medial surface (Fig. 18B); gonocoxite 2 subtriangular, apex tightly rounded, base with short broad lateral extension, 2 lateral ensiform setae, the apical seta broader and longer, apical nematiform setae on medioventral surface at 0.70 × gonocoxite length.

Holotype.

Male (CUIC) dissected and labeled: HI: Maui Haleakala NW / slope Waikamoi Pres. / trans. 3 @ 1700 m el. / 10-V-1991 sifting / litter J.K. Liebherr // 2 // Mecyclothorax / notobscuricornis / ♂ #5 / det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / notobscuricornis / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Allotype.

Female (CUIC) labeled: HI: Maui Haleakala NW / slope Waikamoi Pres. / trans. 3 @ 1700 m el. / 8-V-1991 scraping / ohia w/ moss & dirt // J.K. Liebherr / collector // Mecyclothorax / notobscuricornis / ♀ photo / det. J.K. Liebherr 2014 // ALLOTYPE / Mecyclothorax / notobscuricornis / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes.

Koolau F.R., Haipuaena, 455 m el., 30-vi-1920, Bryan (BPBM, 2).

Etymology.

The adjectival species epithet notobscuricornis is drawn from the converse name obscuricornis , another species in this group. Why Sharp (1903) used that name is unknown, though it too can be derived from the name of a previously described and related species; Mecyclothorax obscuricolor (Blackburn).

Distribution and habitat.

Mecyclothorax notobscuricornis (Fig. 19) is known from one recent collecting site, the upper Honomanu drainage at 1700 m elevation, and one historical 1920 collecting site near Haipua‘ena Camp along the Koolau Ditch ( Wilcox 1996), 425 m elevation (BPBM, E.H. Bryan, Jr.). Recent records were from sifted leaf litter and from moss and associated humus on the trunk of a large ‘ōhi‘a tree.