Mecyclothorax mordicus, 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 : 32

Taxon classification Animalia Coleoptera Carabidae

(007) Mecyclothorax mordicus sp. n. Figs 15D, 16 G–H, 19

Diagnosis.

Of the pale margined species in this group from Haleakalā that exhibit a smooth pronotal disc, sinuate lateral pronotal margins and a broader pronotal base-MPW/BPW = 1.42-1.52-this species can be diagnosed by more convex eyes-ocular ratio = 1.44-1.55-and the subparallel pronotal lateral margins and protruded hind angles (Fig. 15D). The most similar species is Mecyclothorax manducus (Fig. 20A), which deviates by exhibiting smaller eyes-ocular ratio = 1.40-1.43. If a male is available, the aedeagus can settle the matter, with Mecyclothorax mordicus exhibiting a median lobe with a very short rounded apex distad the ostial opening (Fig. 16G), whereas the median lobe apex of Mecyclothorax manducus is elongate (Fig. 16I). Setal formula 2 1 2 1[sae]. Standardized body length 3.6-3.9 mm.

Description

(n = 4). Head capsule with frontal grooves broad at clypeus, a lateral carina to anterior supraorbital seta; dorsal impression of neck flat to concave; ocular lobe ratio = 0.75-0.77; labral anterior margin broadly, shallowly emarginate; antennae filiform, antennomere with sparse setae, antennomere 3 with pelage of short setae; mentum tooth with sides acute, apex rounded. Pronotum with lateral seta present, basal seta absent; hind angle obtuse, margin rounded posterad; lateral margin subparallel anterad hind angle then divergent; median base moderately depressed, covered with dense longitudinal wrinkles and some punctures; basal margin straight medially, slightly expanded posteriorly mesad laterobasal depressions; median longitudinal impression shallow, finely incised; anterior transverse impression deep, broader medially, lined with granulate isodiametric microsculpture and crossed by longitudinal wrinkles; anterior callosity elevated, flat, crossed by longitudinal wrinkles; front angles little projected, tightly rounded; front angles slightly farther apart than hind angles; APW/BPW = 1.03-1.04; lateral marginal depression moderately narrow, edge upturned; laterobasal depression smooth, concave, surface continuous with lateral depression. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process medially depressed, sides broadly upraised. Elytra subquadrate, MEW/HuW = 1.81-1.86; disc moderately convex, sides more sloped; basal groove angled anterad from 3rd stria to meet tightly rounded humeral angle; parascutellar seta present; parascutellar striole with 3-5 punctures, striole shallow between punctures; sutural interval more convex than lateral intervals, sutural juncture upraised; sutural and 2nd striae of subequal depth from base to apex; intervals 2-8 convex, associated striae deep, minute irregularities present at base, smooth on disc and at apex; 7th and 8th interval of similar convexity mesad subapical sinuation; 2 dorsal elytral setae situated at 0.30 × and 0.60 × elytral length, anterior setal impression spanning interval 3, posterior impression spanning ½ of interval width; subapical seta present, apical seta absent; lateral elytral setae arranged as anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression moderately narrow at humerus, broader posterad, beadlike at subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~4 shallow punctures in one row; metepisternal width to length ratio = 0.81; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1-5; suture between ventrites 2 and 3 complete; apical ventrite of male with 2 setae. Legs-metatarsomere 1/metatibial length ratio = 0.20; 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 isodiametric sculpticells in transverse rows; pronotal disc with transverse mesh, sculpticell breadth 2 × length; pronotal median base with transverse mesh, sculpticell breadth 2 × length; elytral disc glossy, transverse mesh to transverse lines present laterally; elytral apex with shallow transverse mesh, sculpticell breadth 2 –3× length; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomere 1 flavous, antennomeres 2-3 rufoflavous, 4-11 rufobrunneous; pronotal disc rufopiceous, anterior callosity, lateral margins broadly, and median base rufoflavous; proepipleuron and proepisternum rufoflavous; elytral disc with intervals 2-5 piceous from base to apical 5/6, and interval 6 piceous on disc; sutural interval rufobrunneous basally and on disc, flavous in apical half; elytral intervals 7-9 plus marginal depression flavous, apex broadly flavous to juncture of intervals 3 and 4; elytral epipleuron pale creamy ivory, metepisternum rufobrunneous; abdomen with ventrites 1-3 medially and 4-6 mediobasally piceous; apical 2/3 of apical abdominal ventrite 6 flavous; metafemur flavous; metatibia flavous with brunneous cast.

Male genitalia (n = 2). Aedeagal median lobe gracile but with tip very broadly rounded and little extended beyond ostial opening, distance from parameral articulation to tip 4.4 × depth at midlength (Fig. 16G); median lobe not curved to the right except near bluntly rounded tip in ventral view (Fig. 16H); internal sac unornamented, lightly sclerotized flagellar plate visible in lateral and ventral views (Figs 16 G–H).

Holotype.

Male (CUIC) dissected and labeled: HI: Maui Haleakala Hana / For. Res. Ridge E / Heleleikeoha Str. 12-V- / 1998 lot 09 1760 m el. / sifting ohia litter C.P. / Ewing // 2 // Mecyclothorax / mordicus / ♂ #2 / det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / mordicus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes.

HI: Maui, Haleakala, Hana For. Res., Horseshoe Bog, sifting Metrosideros litter, 1830 m el., 12-v-1998 lot 08 (CUIC, 1), Kuhiwa Str., beating Myrsine lessertiana , 1780 m el., 12-v-1009 lot 13 (CUIC, 1), same data a holotype (CUIC, 1).

Etymology.

The adjectival mordicus means biting in the mandibular sense, continuing the string of epithets that started with daptinus above.

Distribution and habitat.

Recorded localities of Mecyclothorax mordicus are restricted the Hāna Bogs region, specifically to proximate locales at Horseshoe Bog and near the headwaters of Kuhiwa and Helele‘ike‘oha Streams (Fig. 19). Beetles of this species have been found in ‘ōhi‘a litter, and by beating Myrsine lessertiana (kolea lau nui).