Mecyclothorax cordaticollaris, 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 : 141-145

Taxon classification Animalia Coleoptera Carabidae

(056) Mecyclothorax cordaticollaris sp. n. Figs 62J, 73C, 74C, 76 C–D, 77

Diagnosis.

Like Mecyclothorax cordaticollis (Fig. 73B) or Mecyclothorax subconstrictus (Fig. 73D) in the setal formula-2 2 1 0-but with much deeper elytral striae, the discal striae 1-5 distinctly punctate with the punctures expanding strial breadth (Fig. 73C). The pronotal median base is minutely punctate, ~15 distinct punctures each side, with the punctures elongate at the juncture with the disc. The pronotal disc is glossy, with obsolete transverse-mesh microsculpture, sculpticell breadth 3 × length, and the median base is glossy medially, and with an isodiametric mesh present laterally between the punctures. The elytra are relatively broader basally than in Mecyclothorax cordaticollis or Mecyclothorax subconstrictus , with the basal groove distinctly recurved to meet the angulate humerus, the angle defined by a hitch at the base of the lateral marginal depression. Standardized body length 3.9-4.4 mm.

Description

(n = 4). Head capsule with frontal grooves broad near clypeus, straight, lateral carina to anterior supraorbital seta; dorsal surface of neck flat to slightly concave; eyes moderately convex, ocular ratio = 1.48-1.50, ocular lobe ratio = 0.78-0.82; labral anterior margin very shallow emarginate medially; antennae filiform, antennomeres 2-3 with sparse pelage of short setae; mentum tooth with sides right, apex rounded. Pronotum transverse, MPW/PL = 1.24-1.27, constricted basally, MPW/BPW = 1.47-1.55; hind angle right, lateral margins subparallel to slightly convergent anterad projected angles; basal margin slightly, evenly convex between laterobasal depressions; median longitudinal impression shallow, finely incised; anterior transverse impression moderately deep, smooth, finely incised; anterior callosity slightly convex, smooth, glossy; front angles very slightly produced, broadly rounded; apical and basal pronotal widths subequal, APW/BPW = 0.95-1.0; lateral marginal depression narrow, edge upturned anterad seta, slightly broader at front angle, beadlike margin from midlength to basal sinuation; laterobasal depression smooth laterad median base, broadly raised in explanate lateral margin. Proepisternum with 5 minute punctures along hind margin; prosternal process with narrow median impression, lateral margins broadly beaded between coxae. Elytra broadly ovoid, disc moderately convex, sides more so; MEW/HuW = 2.11-2.16; parascutellar seta present; parascutellar striole with 4 punctures, continuous between punctures; sutural interval only slightly more convex than lateral intervals in basal half, more convex apically; sutural and 2nd striae of subequal depth from base to apex; elytral intervals 2-4 moderately convex, lateral intervals flatter; 8th interval slightly more convex than fused apical portion of striae 5 + 7; one dorsal elytral seta at 0.23 –0.28× elytral length, setal impression small, spanning ½ width of interval 3; apical and subapical setae absent; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression narrow, margin upturned, beadlike near subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~10 punctures in 2-3 rows; metepisternal width to length ratio = 0.65; 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 reduced laterally, effaced; apical male ventrite with 2 marginal setae, apical female ventrite with 4 equally spaced marginal setae plus median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.21; metatarsomere 4 length along outer lobe 1.25 × medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci shallow, narrow, median area broad. Microsculpture of vertex distinct, transversely stretched, sculpticell breadth 2 –3× length; elytral disc with shallow transverse mesh, sculpticell breadth 3 –4× length, apex with more developed transverse mesh of same dimensions; metasternum with shallow transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomeres 1-3 flavous, 4-11 darker, more brunneous; pronotal disc rufobrunneous with piceous cast, lateral margins, base, and apex rufoflavous; proepipleuron rufoflavous, proepisternum rufobrunneous with piceous cast; elytral disc rufobrunneous, sutural interval paler rufous basally, rufoflavous apically; elytral lateral marginal depression narrowly rufoflavous, apex contrastedly flavous from apical terminus of interval 4; elytral epipleuron rufoflavous, metepisternum rufopiceous; abdominal ventrites 1-2 rufopiceous, ventrites 3-5 medially rufopiceous, laterally paler, apical ventrite with apical half flavous; metafemur flavous; metatibia flavous with brunneous cast.

Male genitalia (n = 1). Aedeagal median lobe extremely slender, apically narrowed, needlelike, distance from parameral articulation to tip 5.9 × depth at midlength (Fig. 76C); apex elongate, very narrow, angled slightly downward about half way along apical extension, with tip narrowly rounded; median lobe straight in ventral view, right and left margins approaching each other for 1/3 lobe length in this view, tip narrowly pointed (Fig. 76D); internal sac without apparent microtrichial fields in uneverted specimen, flagellar plate length estimated to be 0.35 × parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix broad basally at vagina, with elongate, digitiform apical lobe, overall bursal length 0.74 mm, with apical lobe 0.51 mm long × 0.19 mm broad, and basal bulb at vagina 0.23 mm long × 0.41 mm broad (Fig. 62J); bursal walls smooth, only lightly wrinkled, the walls of apical lobe thinner, less stained than broad base with darker staining and thicker wrinkles; gonocoxite 1 with 4 apical fringe setae, medial surface lined with 7-10 smaller setae (Fig. 74C); gonocoxite 2 falcate with subacuminate apex, base broadly extended by short panhandle with curved terminus, 2 short lateral ensiform setae with apical seta longer and broader, apical nematiform setae on medial surface at 0.68 × gonocoxite length.

Holotype.

Male (CUIC) dissected and labeled: HI: Maui Haleakala N.P. / Kaupo Gap el. 1160 m / N20°40'43", W156°08'09" / 17-V-2001 lot 05 beating / ferns J.K. Liebherr // 1 // HOLOTYPE / Mecyclothorax / cordaticollaris / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes.

HI: Maui, Kaupo Gap Tr., beating Pipturus , 1340 m el., 31-viii-1996 lot 01, Ewing (CUIC, 1), sifting Acacia koa /fern/moss litter, 1495 m el., 17-18-v-2001 lot 03, Liebherr (CUIC, 1), same data as holotype (CUIC, 1).

Etymology.

This species’ great similarity to Mecyclothorax cordaticollis leads to use of the similar epithet cordaticollaris . As in the former name, this adjectival epithet is meant to signify the cordate pronotum.

Distribution and habitat.

Mecyclothorax cordaticollaris is distributed in the Koa Mesic Forest lining the eastern margin of Kaupō Gap (Fig. 77). Specimens have been collected from 1170-1495 m elevation in litter including fern and moss humus plus koa leaves and phyllodes, as well as by beating low soft ferns and Pipturus ( māmaki).