Mecyclothorax antaeus, 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 : 62-66

Taxon classification Animalia Coleoptera Carabidae

(022) Mecyclothorax antaeus sp. n. Figs 30E, 33D, 34 J–L, 36, 37A

Diagnosis.

This species can be diagnosed by the broad elytra with sides subparallel at midlength (Fig. 33D), a configuration shared with Mecyclothorax robustus and Mecyclothorax haydeni (Fig. 38 C–E), however the discal elytral striae are smooth to only minutely punctate instead of distinctly punctate, and the associated intervals are only moderately convex instead of convex. The pronotum has the lateral margin parallel to slightly convergent anterad the right hind angles, and the pronotal median base is covered with fine punctures. Beetles of the other two species have pronota with parallel to divergent basal lateral margins. The male aedeagal median lobe of Mecyclothorax antaeus males has the apex elongate and parallel sided with a downturned tip (Fig. 34 J–K), versus the apically flattened median lobe of Mecyclothorax robustus (Fig. 41) and the elongate, evenly curved apex observed in males of Mecyclothorax haydeni (Fig. 43). Setal formula 2 2 2 2. Standardized body length 4.6-5.9 mm.

Description

(n = 5). Head capsule with frontal grooves broad near clypeus, a lateral carina to anterior supraorbital seta; dorsal surface of neck flat to slightly concave; eyes moderately convex, ocular ratio = 1.46-1.50, ocular lobe distinctly protruded from gena, ocular lobe ratio = 0.71-0.78, an abruptly depressed slot at juncture of lobe and gena; labral anterior margin broadly shallowly emarginate; antennae filiform, antennomeres 2-3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum subcordate, quadrate to slightly transverse, MPW/BPW = 1.38-1.45, MPW/PL = 1.18-1.25; hind angle right, projected, the margin behind convex; basal margin slightly convex between hind angles; median longitudinal impression shallow, finely incised; anterior transverse impression broad, shallow, crossed by longitudinal wrinkles, lined with granulate isodiametric microsculpture; anterior callosity slightly elevated, covered with dense longitudinal wrinkles, strigose; front angles slightly projected, rounded; base broader than distance between front angles, APW/BPW = 0.86-0.98; lateral marginal depression moderately broad, explanate, edge upturned; laterobasal depression broad, smooth, with median tubercle. Proepisternum with 6 indistinct punctures along hind marginal groove; prosternal process medially depressed, with broad lateral marginal bead. Elytra subquadrate, humeri moderately narrow, rounded, sides subparallel at midlength; elytral disc convex, sides progressively sloped laterally; basal groove recurved to subangulate humeri, the lateral margin upraised, and humeral angle defined by hitch at base of lateral marginal depression, MEW/HuW = 2.02-2.13; parascutellar seta present; parascutellar striole deep with 5 punctures; sutural interval more convex than intervals 2-4, sutural juncture upraised; sutural and 2nd striae of subequal depth from base to apex; sutural and lateral discal striae 2-6 minutely punctate, striae slightly irregular along length; 7th and 8th intervals of similar convexity mesad subapical sinuation; 2 dorsal elytral setae at 0.29 –0.34× and 0.55 –0.60× elytral length, setal impressions small, extended over ½ width of interval 3; apical and subapical setae present; lateral elytral setae arranged in an anterior series of 7(6) setae and a posterior series of 6 setae; elytral marginal depression moderately broad in anterior half, narrowed anterad subapical sinuation; subapical sinuation shallow, broad. Mesepisternum with ~14 punctures in 2-3 rows; 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 marginal setae, apical ventrite of female with 4 equally spaced setae and median patch of 4(5) short, subequal setae. Legs-metatarsomere 1/metatibial length ratio = 0.20; metatarsomere 4 length along outer lobe 1.33 × medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci deep, broad, median area strigose to carinate. Microsculpture of vertex an isodiametric mesh; pronotal disc with transverse mesh, sculpticell breadth 2 –3× length; pronotal median base with distinct to granulate isodiametric mesh; elytral disc and apex with transverse mesh, sculpticell breadth 3 × length, to transverse lines; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous with a purplish reflection; antennomere 1 flavous, 2-3 rufoflavous, 4-11 rufobrunneous; pronotal disc rufobrunneous with purplish reflection; pronotal margins rufoflavous inside front angles, otherwise concolorous with disc; proepipleuron rufoflavous, proepisternum rufobrunneous; elytral disc rufobrunneous with purplish reflection; sutural interval concolorous with disc basally, rufoflavous apically; elytral lateral marginal depression rufoflavous, apex slightly paler than disc, rufoflavous to position of subapical seta; elytral epipleuron rufoflavous laterally, rufobrunneous ventrally, metepisternum rufobrunneous; abdomen with ventrites medially rufobrunneous, marginally rufoflavous; apical half of ventrite 6 paler, flavous; metafemur flavous; metatibia rufoflavous.

Male genitalia (n = 4). Aedeagal median lobe gracile, distance from parameral articulation to tip 4.1 × depth at midlength (Fig. 34 J–K), apex narrowly extended beyond ostial opening, tip downturned with flat apical face; median lobe broadly curved rightward in ventral view, the apex parallel sided and tip blunt (Fig. 34L); internal sac tubular, elongate, with two ventral microtrichial patches, a larger basal patch and a smaller apical patch situated just distad a median constriction (Fig. 34J); flagellar plate of moderate size, length of sclerotized internal face 0.38 × distance from parameral articulation to tip.

Female reproductive tract (n = 1). Bursa copulatrix columnar with rounded apex, bursa narrower in apical half, length 1.10 mm, apical breadth 0.32 mm, basal breadth 0.51 mm, broader than width of vagina (Fig. 30E); bursal walls translucent basally with think wrinkles, apical surface shagreened but not wrinkled; gonocoxite 1 with 3-4 apical fringe setae and 6-9 smaller setae on medial surface (Fig. 37A); gonocoxite 2 narrowly subtriangular with subacuminate apex, base extended laterally as a thin extension, 2 lateral ensiform setae, the apical seta slightly broader, apical nematiform setae on medioventral surface at 0.74 × gonocoxite length.

Holotype.

Male (CUIC) labeled: HI: Maui / Haleakala N.P. / Kipahulu west rim ESE / Kuiki sift humus ex ohia 15-V-1993 lot 03 / el. 1850 m // J.K. Liebherr & / A.C. Medeiros / Collectors // HOLOTYPE / Mecyclothorax / antaeus / Liebherr / J.K. Liebherr 2015 (black-margined red label).

Paratypes.

39 paratype specimens plus 1 non-type specimen (see Appendix).

Etymology.

Antaeus was a "giant Libyan wrestler whose strength was renewed when he touched the earth ( Brown 1956)," an apt epithet for this close relative of Mecyclothorax robustus . The name is treated as a noun.

Distribution and habitat.

Mecyclothorax antaeus is a species of the Manawainui Planeze, with known collection localities lining the western rim of Kīpahulu Valley (Fig. 36) at 1200-2145 m elevation. Specimens have been collected in association with ‘ōhi‘a, either from humus around tree bases, or from humus on tree trunks.