Mecyclothorax oculellus, 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 : 269-272

Taxon classification Animalia Coleoptera Carabidae

(107) Mecyclothorax oculellus sp. n. Figs 143B, 147

Diagnosis.

This species is one of the few Hawaiian Mecyclothorax that lacks dorsal elytral setae. Among the Haleakalā fauna only Mecyclothorax xestos (Fig. 90D) of the Mecyclothorax microps group shares this feature. The parascutellar seta is absent, a unique occurrence within the Mecyclothorax palustris group, and the pronotum is broader relative to the elytra (Fig. 143B), MEW/MPW = 1.44, than in any other species with concolorous elytral disc and margins in the group. The bicolored Mecyclothorax bicoloris and Mecyclothorax bicoloratus exhibit similar somite proportions (Fig. 143 C–D). The elytral microsculpture is a well-developed mesh of isodiametric sculpticells arranged in transverse rows on the inner intervals, the sculpticells more transverse on intervals 7 and 8. Setal formula 2 1 0 1[sae]. Standardized body length 4.2 mm.

Description

(n = 1). Head capsule with frontal grooves broadest near clypeus, expanded medially inside broad convexity anterad eyes, terminated posteriorly at thin carina mesad supraorbital seta; dorsal impression of neck slightly concave; ocular lobe barely protruded from gena, eyes relatively flat, ocular ratio = 1.43, ocular lobe ratio = 0.81; labral anterior margin angularly emarginate 1/6 labral length; antennae filiform, antennomeres 2-3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum with lateral margins convex anterad a deep sinuation at the right hind angles, the lateral margins parallel for 1/6 pronotal length, MPW/PL = 1.21, MPW/BPW = 1.61; median base nearly coplanar with disc, shallow strigose wrinkles each side; basal margin very slightly convex between laterobasal depressions; median longitudinal impression very shallow, middle of disc flat; anterior transverse impression broad, shallow medially, more marked laterally, finely incised mesad front angles; anterior callosity moderately convex, smooth; front angles slightly projected, tightly rounded; pronotal apex broader than base, APW/BPW = 1.07; lateral marginal depression narrow, beaded laterally, edge upturned and broader at front angles; laterobasal depression smooth, continuous with lateral depression. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process with broad median depression, lateral margins broadly beaded between coxae. Elytra subquadrate, moderately broad basally, disc flat, sides moderately sloped; basal groove angulate at sutural stria, extended to angulate humerus defined by juncture of basal groove and much broader lateral marginal depression, MEW/HuW = 1.95; parascutellar striole with 3-4 punctures, striole very shallow between punctures; sutural interval more convex than lateral intervals, sutural juncture upraised; sutural and 2nd striae of subequal depth and punctation on disc, sutural stria deeper and more finely incised at apex; discal intervals 2-5 slightly convex, striae 2-5 progressively shallower and less punctate laterally, stria 6 a series of punctures, and stria 7 marked by sparse elongate irregularities at midlength, shallowly continuous apically; 8th interval of similar convexity to apical fused portion of striae 5 + 7; subapical seta present in apical portion of stria 7 laterad apex of stria 2; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression moderately narrow posterad humerus, edge slightly upturned there, narrowed to a bead at subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~13 punctures in 2-3 rows; metepisternal width to length ratio = 0.76; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1-5 and lateral depressions on ventrites 3-6; suture between ventrites 2 and 3 complete; apical female ventrite with 4 equally spaced setae and median trapezoid of 4 subequal, short setae; Legs-metatarsomere 1/metatibial length ratio = 0.19; metatarsomere 4 length along outer lobe 1.3 × medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci broad, shallow, basal tarsomere medially subcarinate. Microsculpture of vertex a shallow transverse mesh, sculpticell breadth 2 –3× length; pronotal disc with shallow transverse mesh, sculpticell breadth 2 –4× length, median base with distinct isodiametric mesh; metasternum with a shallow transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration (lone holotype specimen is teneral) of vertex rufoflavous; antenna rufoflavous basally, dusky rufoflavous apically; pronotal disc rufoflavous, lateral margins narrowly, and base and apex flavous; proepipleuron flavous, proepisternum rufobrunneous with rufoflavous margins; elytral disc rufoflavous, sutural interval flavous basally and apically, concolorous on disc; elytral marginal depression narrowly flavous, apex gradually paler, flavous from apical terminus of interval 4; elytral epipleuron flavous, metepisternum rufobrunneous; abdominal ventrites 1-5 rufoflavous, apical half of ventrite 6 flavous; metafemur flavous; metatibia flavous with rufoflavous cast.

Female reproductive tract. The lone female specimen was not dissected.

Holotype.

Female (BPBM) labeled: HI: Maui Is. Haleakala / Waikamoi N.C.P. 1750 m el. / 20°47.21'N, 156°13.82'W / 12-III-2002 R. Takumi / pyr. fog mossy ohia // HOLOTYPE / Mecyclothorax / oculellus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Etymology.

The very small eyes characterizing this species are the basis for using oculellus -small eye-as the species epithet. The diminutive oculellus was used instead of ocellus due to the very specific meaning of the latter term in entomology.

Distribution and habitat.

Mecyclothorax oculellus is known only from a specimen collected at 1750 m elevation in the Honomanu drainage of Waikamoi Nature Conservancy Preserve (Fig. 147). The type specimen was collected in pyrethrin fog samples taken from mossy ‘ōhi‘a, along with specimens of 12 other Mecyclothorax spp.: Mecyclothorax bicoloris , Mecyclothorax cognatus , Mecyclothorax filipoides , Mecyclothorax kipwilli , Mecyclothorax laetus , Mecyclothorax mauiae , Mecyclothorax orbiculus , Mecyclothorax ovipennis , Mecyclothorax perstriatus , Mecyclothorax planatus , Mecyclothorax sobrinus , and Mecyclothorax unctus .