Mecyclothorax kayballae, Liebherr, James K., 2013

Liebherr, James K., 2013, The Mecyclothorax beetles (Coleoptera, Carabidae, Moriomorphini) of Tahiti, Society Islands, ZooKeys 322, pp. 1-170 : 70-72

58. Mecyclothorax kayballae sp. n.

Diagnosis.

Of the Mecyclothorax viridis group species with evident transverse elytral microsculpture and basally obsolete elytral striae 1-5 (Fig. 32), this species uniquely lacks dorsal elytral setae; setal formula 2201. The dorsal coloration is dark, rufopiceous with a blue reflection (Fig. 32A), much darker than all other species in the group save Mecyclothorax ninamu (Fig. 31A), but beetles of that species are much smaller - 3.5-4.0 mm - versus those of Mecyclothorax kayballae ; standardized body length 4.3-4.7 mm. Head with frontal grooves very shallow posteriorly, separated from anterior supraorbital seta by fine, low carina, frons mesally with radiating wrinkles, groove broadly, triangularly depressed anteriorly near frontoclypeal suture; eyes moderately convex, ocular ratio 1.49-1.50 (n = 3), ocular lobe protruded, posterior margin of lobe meeting gena at shallow groove with carina behind, ocular lobe ratio 0.80-0.83; antennae submoniliform, antennomere 8 length 1.80 × maximal breadth. Pronotum cordate, base narrow, MPW/BPW = 1.61-1.63, moderately transverse, MPW/PL = 1.20-1.24; hind angles right to slightly obtuse, lateral margins convergent immediately anterad angle then distinctly divergent; median base convex medially, moderately depressed relative to convex disc, 12-14 distinct punctures each side plus 5-7 elongate wrinkles along margin with disc; anterior transverse impression finely incised laterally with fine wrinkles behind, obsolete near midline; front angles rounded, slightly protruded, lateral marginal depression narrow with beaded edge laterally, depression broader with less upraised margin at front angle; laterobasal depression a narrow, punctate expansion of lateral depression, defining laterally a triangular raised area bearing the basal seta articulatory socket. Elytra ovate, convex, scutellum depressed relative to disc, sides sloping to near vertical at lateral elytral depression; humeri proximate, but elytral margins extended laterally in a broad even curve posteriorly, MEW/HuW = 2.41-2.51; striae 1-6 shallow with distinct rounded punctures on disc, striae much shallower and impunctate near basal groove, appearing obsolete in dorsal view but traceable if basal surface of elytra is positioned horizontally in field of view; stria 7 very shallow with periodic shallow dimples along length; humeri angulate, elytral basal groove more distinctly curved laterally near juncture with lateral marginal depression; lateral marginal depression narrow throughout length, only slightly broader near midlength; elytral striae 2-7 reduced over much of elytral apex, the apex of stria 7 impressed apicad subapical sinuation, with interval 8 more convex at that point resulting in a short, subcarinate ridge adjacent to stria 7; elytral lateral setae 7 + 6. Microsculpture of frons transverse, obsolete, the surface glossy between areas with visible sculpticells, neck with more visible transverse microsculpture, the rows including isodiametric and transverse sculpticells; pronotal disc with regular, shallow transverse mesh, sculpticell breadth 2 –3× length; discal elytral intervals covered with a mixture of transverse sculpticells, sculpticell breadth 3 × length, and transverse lines. Coloration of frons and vertex rufopiceous, clypeus and labrum rufobrunneous; antennomeres 1-4 rufoflavous, 5-11 with brunneous cast; pronotal disc rufopiceous, lateral marginal depressions narrowly rufobrunneous, median base dark rufous; elytral disc rufopiceous in basal half, rufous in apical half, sutural interval paler, rufobrunnous only near apex; lateral marginal depression narrowly rufobrunneous; femora and tibiae contrasted with body coloration, rufoflavous.

Male genitalia. Aedeagal median lobe distinctly dorsally curved, apex very short, the tip subacuminate (Fig. 30F).

Female reproductive tract. Bursa copulatrix and vagina separated by a distinct constriction (Fig. 6A), length of bursa plus vagina slightly more than twice bursal breadth compressed under cover slip; basal gonocoxite 1 elongate, with apical fringe of four setae, three larger setae laterally and one smaller, isolated seta medially, 5-6 setae along mesal margin and several more on ventral face (Fig. 9C); apical gonocoxite 2 broadly extended laterally at base, apex subacuminate, lateral margin broadly arcuate, with two lateral ensiform setae, the apical seta broadened along shaft, one dorsal ensiform seta; apical sensory furrow with two apical nematiform setae and two furrow pegs.

Holotype male (MNHN) labeled: French Polynesia: Tahiti Nui / Mt. Marau road el. 1125 m / 4-IX-2006 lot 01 / 17°36.437'S, 149°33.110'W / beat dead tree fern fronds / wet rock face J.K. Liebherr // 1 // HOLOTYPE / Mecyclothorax / kayballae / J.K. Liebherr 2013 (black-bordered red label).

Paratypes: same data as holotype (CUIC, 2). The paratypes have been dissected for male genitalic and female reproductive tract description.

Etymology.

This species is named in honor of Dr. Kathleen Ball for her support for and active engagement in the carabidological community. It should be noted that Mecyclothorax kayballae and Mecyclothorax balli , named by Georges Perrault in honor of Professor George Ball, co-inhabit Mont Marau, establishing the possibility of collecting both species during a one day’s trip to the summit.

Distribution and habitat.

This species is known from the type series collected at 1125 m elevation on Mont Marau. The beetles were beaten from dead fern fronds that were associated with living plants growing on a wet rock face.