Mecyclothorax timberlakei, 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 : 193-194

Taxon classification Animalia Coleoptera Carabidae

(080) Mecyclothorax timberlakei sp. n. Figs 96F, 100A, 101

Diagnosis.

Of the five Haleakalā species of this group with the lateral pronotal seta present (Fig. 100), this species (Fig. 100A) can be diagnosed by the elongate convergence of the pronotal lateral margins anterad the acute hind angles. Like Mecyclothorax crassuloides (Fig. 100B) and Mecyclothorax crassulus (Fig. 100C), all discal striae save the sutural are reduced so much that they can at best be traced by very shallow serial punctures; the 8th interval remains well developed, deep and broad along the lateral margin of the elytron. This species can be told from the above two by the relatively broader pronotal base; MPW/BPW = 1.63, versus values of 1.67-1.79. Setal formula 2 1 2 0. Standardized body length 4.9 mm.

Description

(n = 1). Head capsule with frontal grooves deep, directly divergent from clypeus to mesad anterior supraorbital seta, broad convexity laterally; dorsal impression of neck slightly concave; eyes large, moderately convex, ocular ratio = 1.54, ocular lobe ratio 0.85; labral anterior margin angularly emarginate medially to 1/6 of length; antennae filiform, antennomeres 2-3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum slightly transverse, MPW/PL = 1.16; lateral margins convergent for 0.2 × pronotal length anterad hind angles; median base depressed relative to disc, ~20 small, isolated punctures each side; basal margin straight medially, margin anteriorly curved laterad laterobasal depressions; median longitudinal impression very finely incised within slight depression of disc, crossed by indistinct transverse wrinkles; anterior transverse impression very shallow, broad, obsolete medially, smooth but crossed by minute longitudinal wrinkles; anterior callosity slightly convex, smooth, glossy; front angles moderately produced, tightly rounded; pronotal apical width slightly greater than basal width, APW/BPW = 1.05; lateral marginal depression narrow, edge upturned, slightly broader at front angle; laterobasal depression smooth, glossy surface continuous with lateral depression. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process narrow, evenly depressed medially. Elytra ovoid, disc convex overall, slightly depressed along suture, distinctly sloped laterally to marginal depression; basal groove briefly, angularly curved to subangulate humerus, MEW/HuW = 2.42; parascutellar seta present; parascutellar striole brief with 3-4 punctures, deep and continuous between punctures; sutural interval convex throughout length, but crossing depressed medial portion of disc; discal intervals 2-4 and beyond laterally flat, difficult to demark; sutural stria continuous from base to apex, minutely punctate basally, smooth and deeper apically; 8th interval laterad 7th stria slightly more convex than fused apical portion of striae 5 + 7; 2 dorsal elytral setae at 0.20 × and 0.45 –0.48× elytral length, setal impressions shallow, spanning ½ width of interval 3; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression broadest at humeral angle, margin upturned in basal half, beaded near subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~10 large punctures in 2-3 rows; metepisternal width to length ratio = 0.68; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1-5, lateral depressions on ventrites 3-6; suture between ventrites 2 and 3 partially effaced; apical male ventrite with 2 marginal setae. Legs-metatarsomere 1/metatibial length ratio = 0.20; 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 transverse mesh, sculpticell breadth 2 –3× length; pronotal disc with shallow transverse mesh to transverse lines, the surface glossy in part, median base glossy, with indistinct transverse sculpticells laterally; elytral disc with shallow transverse mesh, sculpticell breadth 2 × length, apex with such a mesh mixed with isodiametric sculpticells; metasternum with transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufous with a piceous cast; antennomeres 1-3 rufoflavous, 4-11 rufobrunneous; pronotal disc and margins rufous; proepipleuron rufoflavous, proepisternum rufoflavous dorsally, rufobrunneous ventrally; elytral disc and margins rufous, sutural interval concolorous basally, rufoflavous apically; elytral apex gradually paler, rufoflavous apicad subapical sinuation; elytral epipleuron and metepisternum rufoflavous; abdominal ventrites 1-3 rufobrunneous, ventrites 4-6 rufoflavous; metafemur rufoflavous; metatibia rufoflavous with brunneous cast.

Male genitalia (n = 1). Aedeagal median lobe gracile, distance from parameral articulation to tip 4.6 × depth at midlength (Fig. 96F); apex narrowly and sinuously extended 3 × its depth beyond ostial opening, the tip narrowly rounded; internal sac broad, with projected, pineapplelike lobe bearing sclerotized macrospicules at midlength on dorsal surface, and dense, brownish microspicules covering ventral surface; flagellar plate short, length 0.33 × parameral articulation-tip distance.

Holotype.

Male (UCRC) dissected and labeled: Haleakala / Maui Jl 1919 // Keanae / Pali // above / 5000 ft. // Astelia / veratroides // Timberlake coll. // Univ. Calif. Riverside / Ent. Res. Museum / UCRC ENT 00039164 // HOLOTYPE / Mecyclothorax / timberlakei / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Etymology.

This species honors the many entomological contributions of Phillip H. Timberlake, including the collection of the only known specimen of this species in 1919. Mr. Timberlake specialized in Hymenoptera , especially bees, and was an associate entomologist with the Hawaiian Sugar Planter’s Association from 1914-1924 before completing his long and distinguished career at the Citrus Experiment Station, Riverside, CA ( Hurd et al. 1982).

Distribution and habitat.

Mecyclothorax timberlakei is known from a single specimen labeled "Keanae Pali, above 5000 ft." This locality (Fig. 101) would have been most easily accessed from above timberline by walking down the western rim of Ko‘olau Gap-Ke‘anae Valley to the designated elevation. The labeled host plant substrate Astelia veratroides is now a junior synonym of Astelia menziesiana (painiu), an epiphytic lily found in mesic to wet forest.