Mecyclothorax foveolatus, 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 : 93-95

Taxon classification Animalia Coleoptera Carabidae

(034) Mecyclothorax foveolatus sp. n. Figs 45 M–N, 46E, 47E, 50B, 51

Diagnosis.

This and the following species, Mecyclothorax interruptus , are cryptic sibling species with only subtle differences both externally (Fig. 50B, D) and in the male genitalia (Fig. 45 M–P), but nevertheless they may be consistently diagnosed morphologically. This species differs from its sibling in its more upraised cuticular microsculpture; 1, vertex covered by a granulate isodiametric mesh, the surface appearing coriaceous, matte and non-reflective; 2, pronotal disc with coriaceous isodiametric and transverse sculpticells in transverse rows, the pronotal base with granulate isodiametric mesh, again the surface with a matte finish. The corresponding microsculpture in Mecyclothorax interruptus individuals is: 1, vertex with isodiametric mesh, the sculpticell surfaces shiny in part; 2, pronotal disc with mixture of isodiametric and transverse sculpticells, the surface iridescent, and pronotal base with flattened isodiametric sculpticells, the surface shiny in part. The discal elytral striae are also smoother in this species, with minute punctulae at the deepest parts of the striae associated with longitudinal irregularities in the strial orientation, whereas in Mecyclothorax interruptus individuals the striae, especially the sutural and 2nd stria, are minutely but clearly punctate in their deepest portions, with those small punctures slightly expanding the stria at its deepest point. The male median aedeagal lobe apex in this species has a distinct obtuse tooth on its dorsal surface (Fig. 45 M–N) versus the lobe apex of Mecyclothorax interruptus males with a rounded dorsal projection (Fig. 45 O–P). The median lobe tip is also flattened apically in this species, versus more evenly rounded in Mecyclothorax interruptus . Setal formula 2 2 2 2. Standardized body length 4.8-5.9 mm.

Description

(n = 5). Head capsule with frontal grooves deep and broad near clypeus, sinuously directed to terminus mesad anterior supraorbital seta; dorsal surface of neck flat to convex; eyes moderately convex, ocular ratio = 1.42-1.50, ocular lobe distinctly projected from gena; ocular lobe ratio 0.79-0.88; labral anterior margin with broad, moderately deep emargination; antennae filiform, antennomere 3 with sparse pelage of short setae; mentum tooth with side acute, apex broadly rounded. Pronotum moderately transverse, MPW/PL = 1.19-1.29, moderately constricted basally, MPW/BPW = 1.38-1.46; hind angle variably obtuse, to right, to slightly acute, apex tightly rounded, lateral margin subparallel anterad angle; median base with dense elongate punctures and longitudinal wrinkles; basal margin nearly straight, slightly convex medially; median longitudinal impression broad, shallow, crossed by wrinkles; anterior transverse impression deeply incised, complete, crossed by longitudinal wrinkles that extend across broadly, slightly convex anterior callosity; front angles slightly projected, rounded; pronotal apical and basal widths subequal, APW/BPW = 0.95-1.06; lateral marginal depression moderate, edge broadly upturned; laterobasal depression broad, smooth, with median tubercle. Proepisternum with 6 small, elongate punctures along hind marginal groove; prosternal process broad, medially depressed with lateral marginal bead. Elytra subquadrate, disc slightly convex; basal groove evenly recurved to join lateral marginal depression at rounded humerus; MEW/HuW = 1.79-2.02; parascutellar seta present (on 1 specimen near base of stria 2); parascutellar striole deep, continuous; sutural interval moderately convex, convexity similar to that of lateral intervals of similar breadth; sutural and 2nd striae of subequal depth from base to apex; discal striae 2-4 fused in association with dorsal elytral setae, striae 5 and 6 may be fused behind humerus, intervals moderately convex to convex; 7th and 8th intervals of similar convexity mesad subapical sinuation; 2 dorsal elytral setae at 0.29 × and 0.60 × elytral length, setal impressions foveate, placed within depressed areas associated with strial fusions; apical and subapical setae present; lateral elytral setae arranged as anterior series of 7 setae (or anterior series of 6 with isolated 7th intermediate seta) and a posterior series of 6 setae; elytral marginal depression narrow, lateral margin upturned; subapical sinuation broad and very shallow. Mesepisternum with ~22 distinct punctures 3-4 rows; metepisternal width to length ratio = 0.76; metepisternum/metepimeron suture distinct; metathoracic flight wing configuration an ovoid flap, length 2.1 × breadth, remnant R and M veins present, the flap extended 1/3 length beyond posterior margin of metanotum. Abdomen with indistinct lateral wrinkles on ventrites 1-3; suture between ventrites 2 and 3 complete; apical male ventrite with 2 marginal setae, apical female ventrite with 4 equally spaced marginal setae and median trapezoid of 4 short setae, the basal pair slightly longer. Legs-metatarsomere 1/metatibial length ratio = 0.22; metatarsomere 4 length along outer lobe 1.4 × medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci broad, deep, median area irregular. Microsculpture of elytral disc an elongate transverse mesh, apex with upraised transverse mesh; metasternum with obsolete transverse mesh; laterobasal abdominal ventrites with elongate transverse mesh and glossy areas. Coloration of vertex brunneous; antennomere 1 flavous, antennomeres 2-3 flavous with a piceous cast, 4-11piceous; pronotal disc brunneous with piceous cast, margins broadly rufoflavous; proepipleuron flavous with rufous cast, proepisternum rufopiceous; elytral disc rufobrunneous with piceous cast, sutural interval concolorous, margins concolorous to slightly darker; elytral epipleuron flavous with rufous cast, metepisternum piceous; abdominal ventrites 1-6 piceous medially, flavous laterally, the apical ventrite flavous in apical half; metafemur flavous; metatibia flavous with brunneous cast.

Male genitalia (n = 2). Aedeagal median lobe slender, distance from parameral articulation to tip 6.6 × depth at midlength (Fig. 45M), shaft slightly curved basally, ventral margin straight apically, apex with acute dorsal projection, tip tightly rounded at juncture of flat apical face and ventral margin; in ventral view median lobe slightly curved rightward toward apex, right margin concave, left margin more incurved to apex, apical denticle visible to left of rounded tip (Fig. 45N); internal sac without ornamentation.

Female reproductive tract (n = 1). Bursa copulatrix elongate with broad base at vagina, length 0.60 mm, apical width 0.23 mm, basal width 0.34 mm (Fig. 46E); bursal walls translucent, thinly wrinkled; gonocoxite 1 with 4 apical fringe setae and 4-6 smaller setae on medial surface (Fig. 47E); gonocoxite 2 subtriangular, apex acuminate, base evenly extended from lateral margin, 2 parallel-sided lateral ensiform setae, apical nematiform setae on medioventral surface at 0.79 × gonocoxite length.

Holotype.

Male (CUIC) dissected and 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, / Jr. collectors // HOLOTYPE / Mecyclothorax / foveolatus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes.

HI: Maui: Haleakala N.P., Kipahulu Vy., Central Pali Tr., sift leaf/moss litter, 1200 m el., 29-iv-1991 lot 03, Liebherr/Medeiros (CUIC, 1), Kipahulu west rim ESE Kuiki, sift Metrosideros humus, 1850 m el., 15-v-1993 lot 05, Liebherr/Medeiros (CUIC, 1); Hana For. Res., Kaumakani Peak, pyrethrin fog vegetation, 1165 m el., 08-vi-1999 lot 04, Polhemus (NMNH, 1); Koolau For. Res., Hanawi N.A.R., Kopiliula Str., pyrethrin fog Acacia koa trunk, 1127 m el., 03-v-1998 lot 02, Liebherr (CUIC, 1), Kuhiwa Vy. E rim, pyrethrin fog Metrosideros , 880 m el., 09-vi-1999 lot 04, Polhemus (NMNH, 1), lot 07, Polhemus (NMNH, 2), lot 09, Polhemus (NMNH, 1).

Etymology.

The foveae surrounding dorsal elytral setae of this species are the basis for use of the Latin adjectival foveatus as this species’ epithet.

Distribution and habitat.

Mecyclothorax foveolatus exhibits a highly fragmented distribution comprising five localities spanning the Manawainui Planeze, Kīpahulu Valley, Kaumakani Peak, and Kuhiwa and Kopili‘ula drainages in Hanawī (Fig. 51). The Kopili‘ula record alone is associated with koa , whereas the other records are associated with ‘ōhi‘a; either through sifting leaf litter, humus, or moss, or by using pyrethrin fog on mossy trunks and logs.