Mecyclothorax longidux, 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 : 258-260

Taxon classification Animalia Coleoptera Carabidae

(104) Mecyclothorax longidux sp. n. Figs 136D, 137D, 140 A–B, 141 A–E, 142

Diagnosis.

This species (Fig. 140 A–B) and the following, Mecyclothorax brevidux (Fig. 140 C–D) are together diagnosed among Haleakalā species of the Mecyclothorax ducalis group by: 1, the bisetose pronotum; 2, dark rufous to rufopiceous elytra with concolorous apex; 3, basally constricted pronotum, MPW/BPW = 1.40-1.55 in this species; and 4, moderate body size, standardized body length 5.5-5.7 mm for this species. The elytral striae in individuals of this species are much more distinctly punctate, with the punctures distributed across the discal striae 1-5 where they expand strial breadth. The metafemur has the basal half of the anterior face covered with a piceous cloud, contrasted to the flavous medial coloration of the femur. In contrast, the metafemur in Mecyclothorax brevidux has only the basal 1/5 to 1/3 with piceous infuscation. In both species the femoral apex is darkened to match the rufobrunneous to rufopiceous tibial coloration. The male aedeagal median lobe confirms the value of these characters for diagnosis, with the lobe apex of Mecyclothorax longidux males narrow and elongate, with a slightly downturned tip (Fig. 141 A–B, D), versus a shorter broader lobe apex in males of Mecyclothorax brevidux (Fig. 141 F–I). The spiculation of the internal sac is also more developed in males of this species, with a bipartite dorsal ostial microtrichial patch present as well as a large, heavily spiculated ventral ostial microtrichical patch (Fig. 141 D–E). Setal formula 2 1 2 0.

Description

(n = 5). Head capsule with frontal grooves deep, broad near clypeus, low broad lateral convexity anterad eye, terminated posteriorly mesad low ridge inside anterior supraorbital seta; dorsal impression of neck broad, shallow, visible in dorsal view; eyes large, moderately convex, ocular ratio = 1.53-1.63, ocular lobe ratio = 0.81-0.84; labral anterior margin angularly emarginate to 0.2 × labral length; antennae filiform, antennomeres 2-3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum little transverse, MPW/PL = 1.08-1.20; lateral margins subparallel to slightly convergent for 0.1 × pronotal length anterad slightly obtuse, projected hind angles; median base moderately depressed relative to disc, ~25 minute, isolated punctures each side; basal margin distinctly convex between hind angles; median longitudinal impression finely incised, crossed by indistinct longitudinal wrinkles; anterior transverse impression shallow, broad, finely incised immediately mesad front angles; anterior callosity flat medially, smooth; front angles very slightly produced, tightly rounded; apical width subequal to basal width, APW/BPW = 0.99-1.02; lateral marginal depression obsolete, narrowly beaded laterally, broadly beaded basally, narrowly expanded inside front an gle; laterobasal depression with irregularly punctured surface, margined by narrow U-shaped depression. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process with broad median depression, lateral margins broadly upraised. Elytra subovoid, disc convex, slides sloped to nearly vertical juncture with lateral marginal depression; basal groove slightly curved to subangulate humerus at juncture with broader lateral marginal depression, MEW/HuW = 2.23-2.43; parascutellar striole with 4-5 elongate punctures, striole continuous between punctures; sutural interval more convex than lateral intervals 2-4, sutural juncture upraised; sutural and 2nd striae of subequal depth and similar punctation on disc, 2nd stria reduced in depth and punctation both basally and in apical 1/3 of length; discal striae 2-7 progressively shallower, impressed portions shorter, striae 6-7 reduced to a series of punctures, or stria 7 absent; striae 3-7 absent from elytral apex, surface evenly convex between striae 2 and 8; 2 dorsal elytral setae at 0.26 × and 0.50 –0.53× elytral length, setal impressions moderate, 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; broad, explanate laterad humerus, narrowed and beaded laterally to subapical sinuation; subapical sinuation very shallow, nearly obsolete. Mesepisternum with ~11 punctures in 2-3 rows; metepisternal width to length ratio = 0.74; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1-6, round lateral depressions on ventrites 3-6; suture between ventrites 2 and 3 effaced; apical male ventrite with 2 marginal setae and apical female ventrite with 4 equally spaced setae plus 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 narrow, lateral, upper surface granulate, broadly convex. Microsculpture of vertex an obsolete transverse mesh, sculpticell breadth 2 × length, sculpticells most visible in depressed areas of cuticle; pronotal disc an obsolete transverse mesh, sculpticell breadth 2 –3× length traceable over depressed portions of disc but surface mostly glossy; elytral disc and apex glossy, microsculpture obsolete; metasternum with shallow transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufous with a piceous cast; antennomere 1 rufoflavous, antennomeres 2-11 rufobrunneous; pronotal disc dark rufous with piceous cast, lateral margins, base and apex rufopiceous; proepipleuron rufobrunneous, proepisternum rufous; elytral disc dark rufous, sutural interval rufous basally, rufoflavous apically; elytral lateral marginal depression piceous basally, rufoflavous toward apex; elytral apex rufoflavous apicad subapical sinuation; elytral epipleuron rufoflavous, metepisternum rufobrunneous; abdominal ventrites 1-6 medially rufous with piceous cast, laterally rufoflavous, apical ¼ of ventrite 6 paler, rufoflavous.

Male genitalia (n = 4). Aedeagal median lobe gracile, distance from parameral articulation to tip 3.5 –3.8× depth at midlength (Fig. 141 A–B); apex narrowly extended 3 × its depth beyond ostial opening, tip slightly downturned with apical face variably flattened (Fig. 141 A–B, D); median lobe straight at midlength along shaft, apex offset toward right so that convex left margin is apical in ventral view (Fig. 141C); internal sac broadly expanded ventrally, a bipartite dorsal ostial microtrichial patch and ovoid ventral ostial microtrichial patch, each composed of heavily sclerotized macrospicules (Fig. 141 D–E); flagellar plate of moderate size, length 0.35 × parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix sac-shaped, slightly constricted basally, length 1.14 mm, maximum breadth 0.64 mm, basal constriction 0.43 mm broad (Fig. 136D); bursal walls thick, broadly wrinkled; gonocoxite 1 with 3-5 apical fringe setae, a curved seta at medioapical angle and 5-7 setae on medial surface (Fig. 137D); gonocoxite 2 falcate with long basal panhandle, apex subacuminate, 2 narrow, moderately elongate lateral ensiform setae, apical nematiform setae on medioventral surface at 0.64 × gonocoxite length.

Holotype.

Male (CUIC) dissected and labeled: HI: Maui Hanawi N.A.R. / Pig fence helipad sift / humus ex ohia 21-V- / 1993 lot 04 el. 1575 m // J.K. Liebherr & / A.C. Medeiros / Collectors // HOLOTYPE / Mecyclothorax / longidux / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes.

HI: Maui: Hanawi N.A.R., Kopiliula Str., pyrethrin fog Acacia koa trunk, 1127 m el., 03-v-1998 lot 02, Liebherr (CUIC, 2), Kopiliula Str., uluhe fern under tent, 1125 m el., 03-v-1998 lot 01, Liebherr (CUIC, 1), Kuhiwa Vy., Poouli Cabin, beat vegetation, 1590 m el., 05-v-1998 lot 04, Ewing (CUIC, 2), southeast Keanae, Piinaau Road, 27-vi-1920, Bryan (BPBM, 1); Koolau For. Res. [= Hanawi N.A.R.], Tetraplasandra dipyrena , 1740 m el., 09-viii-1973, Gagné (BPBM, 1), Koolau Gap, Halehaku [= Ke‘anae Valley], beat ferns at night, 1325 m el., 13-v-1998 lot 09, Liebherr (CUIC, 2), beat Rubus (akala) beat at night, 1325 m el., 13-v-1998 lot 08, Liebherr (CUIC, 1), pyrethrin fog Cibotium /log, 1325 m el., 13-v-1998 lot 03, Liebherr (CUIC, 1), Kula Pipeline Rd., 975-1210 m el., 13-vi-1927, Swezey (BPBM, 1); Makawao For. Res., Maile Rd., scrape bark Metrosideros , 1310 m el., 26-v-1997 lot 08, Liebherr (CUIC, 1).

Etymology.

This and the following Mecyclothorax brevidux represent cryptic sibling species best diagnosed by the length of the male aedeagal median lobe (Fig. 141). As both are members of the Mecyclothorax ducalis species group, the Latin stem dux-a leader-is used for both species. In this species dux is combined with the Latin longus to form the noun longidux .

Distribution and habitat.

Mecyclothorax longidux is distributed across the windward face of Haleakalā from upper Kuhiwa Valley on the east to the Waikamoi forest on the west (Fig. 142), within an elevational range of 975-1740 m. To date all collecting series are small; either one or two specimens. The beetles have been collected in association with koa , ‘ōhi‘a, Cibotium ( hāpu‘u), Polyscias kavaiensis ( ‘ohe‘ohe), and Rubus ( ‘ākala). Two specimens were found by beating ferns at night, and one was found in the uluhe fern ( Dicranopteris linearis ) platform mound built under my tent near Kopili‘ula Stream in the very wet Hanawī Natural Area Reserve (a technique of Perkins; see Evenhuis 2007: 34).