Mecyclothorax tihotii, Liebherr, James K., 2012

Liebherr, James K., 2012, New Mecyclothorax spp. (Coleoptera, Carabidae, Moriomorphini) define Mont Mauru, eastern Tahiti Nui, as a distinct area of endemism, ZooKeys 227, pp. 63-99 : 69-72

2. Mecyclothorax tihotii sp. n. Figs 3B5 A–B 6A7A

Diagnosis.

Most similar to Mecyclothorax ballioides Perrault, based on: 1, glabrous, well-indicated pronotal hind angle and briefly sinuate basolateral pronotal margin (Fig. 3B); 2, presence of only the apical elytral seta, the subapical seta associated with the seventh stria absent. However, this species is characterized by presence of only the posterior supraorbital seta, resulting in a setal formula of 1121. The pronotal base is also much broader than in Mecyclothorax ballioides , with MPW/BPW = 1.33-1.36 (n = 2), versus 1.58-1.73 (n = 5) for Mecyclothorax ballioides . Standardized body length 4.1 mm.

Description.

Head capsule withsinuatefrontal grooves that are closest at anterior margin of frons, and divergent laterally on clypeus and also posteriorly toward anterior margin of eye, frons smooth between grooves, a broad convexity laterad grooves from frontoclypeal suture to position immediately dorsad eye; neck convex; ocular lobe abruptly protruded behind, meeting gena at <135° angle, a broad shallow groove at juncture of lobe and gena; ocular ratio 1.42-1.44 (n = 2); ocular lobe ratio 0.81-0.82 (n = 2); labral anterior margin nearly straight, slightly protruded at rounded lateral corners; antennomeres 1-3 glabrous except for apical setae; antennae submoniliform, antennomere 8 length 1.77 × maximum breadth; mentum tooth sides defining an acute angle, apex broadly rounded. Pronotum moderately transverse, MPW/PL = 1.24 (n = 2), glabrous hind angles distinct, slightly obtuse, little projected; lateral margins convergent for very short distance anterad denticulate hind angles; median base slightly depressed relative to disc, sparsely punctate, about 10 small, deep, and isolated punctures each side; basal margin slightly, evenly convex between hind angles; median longitudinal impression finely incised, complete on disc, present as lenticular depression at front of median base; anterior transverse impression complete, shallow medially, finely incised in outer ⅔ of breadth each side; anterior callosity slightly convex, smooth; front angles not protruded, inner margin angulate at juncture with anterior transverse impression; front angles closer together than hind angles, APW/BPW = 0.81-0.82 (n = 2); lateral marginal depression very narrow, edge finely beaded laterally, broader with finely upturned edge at front angle, broad at hind angle, marginal bead arcuately filling surface at angle; laterobasal depression obsolete, posterolateral portion of pronotal disc sloped to meet thick marginal bead at hind angle; proepisternum with 5 distinct punctures along hind margin, proepimeron with indistinct punctures along hind margin; prosternal process broad, lateral margins broadly beaded, slightly depressed medially between procoxae. Elytra subquadrate, the humeri laterally extended, MEW/HuW = 1.83-1.93; elytral disc convex, sides distinctly sloped to vertical juncture with lateral depression; basal groove broadly, evenly curved to tightly rounded humerus; parascutellar seta present, situated near sutural stria; parascutellar striole shallow, 3-punctate, interrupted along length; sutural interval broad, slightly elevated on disc, narrower, more convex apically; discal striae 1-5 with elongate punctures in basal ⅓ - ½ of length, the punctures slightly expanding stria near base, striae 3-6 obsolete on elytral base and humerus; sutural stria fine and deep apically, stria 2 very shallow, broad, incomplete, striae 3-6 obsolete, and stria 7 broad and shallow apicad subapical sinuation; due to reduction of stria 7, interval 8 not subcarinate, but surface outwardly bulging, convex, vertically meeting stria 8; dorsal elytral setae in shallow impressions that span ¾ of interval 3, setation unstable (see Variation section), the anterior seta at 0.23 × elytral length, posterior seta at 0.61 × length; apical elytral seta present, subapical seta absent; lateral elytral setae 7 + 6; elytral marginal depression moderately narrow, edge slightly upturned at humerus, margin beadlike from midlength to subapical sinuation; subapical sinuation shallow, nearly obsolete, elytral margin straight. Mesepisternum with 12 punctures in 2-3 vertical rows; metepisternum short, anterior and mesal margins of subequal length, width to length ratio 0.88; metepisternum separated from metepimeron by distinct suture; metathoracic flight wing an ovoid flap, the broadly rounded apex extended ½ distance to metanotal hind margin; wing vestigium with rudiments of R and M veins. Abdomen with visible ventrites 1-3 irregularly wrinkled laterally, ventrites 3-6 with rounded depressions laterally; suture between visible ventrites 2 and 3 effaced laterally. Metatarsomere 4 slightly emarginated apically, overall length 1.3 × median tarsomere length, both apical and subapical setae present; metatarsal dorsolateral sulci shallow and lateral, tarsomere median area slightly convex. Microsculpture reduced on head, frons glossy, neck with indistinct isodiametric sculpticells; pronotal disc glossy, indistinct transverse mesh with sculpticell breadth 2 × length observable outside areas of reflected light; pronotal median base with swirling transverse mesh, sculpticell breadth 2 × length among punctures; elytral disc covered with well-developed transverse lines connected only occasionally, surface subiridescent; elytral apex with transverse mesh, sculpticell breadth 2 –4× length, mixed with transverse lines; metasternum covered with transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse sculpticells. Coloration of vertex rufous with a piceous cast; antennomere 1 flavous, antennomeres 2-3 rufoflavous, 4-11 rufobrunneous; pronotal disc dark rufous; pronotal margins concolorous with disc, lateral bead piceous, apex and base narrowly rufous; proepipleuron rufoflavous, proepisternum dark rufous; elytral disc dark rufous with silvery metallic reflection; sutural interval rufous basally, concolorous apically; elytral marginal depression rufoflavous apically; elytral epipleuron rufoflavous with a brunneous cast, metepisternum rufobrunneous; abdomen rufobrunneous medially, darker with piceous cast laterally; apical ⅓ of visible ventrite 6 rufoflavous; metafemur rufoflavous; metatibia rufoflavous with brunneous cast.

Variation. Although this species is characterized by the presence of two dorsal elytral setae, the two known specimens vary in this regard. The male holotype exhibits only an anterior seta on the left elytron, and only a posterior seta on the right. The female allotype has both anterior and posterior setae present on the left elytron, but only the anterior seta on the right side.

Male genitalia. Aedeagal median lobe narrow and straight basally, right lateral view (Fig. 5A), curved downward apicad articulatory projection of parameres, apex broadly rounded, a large ostial flap at apical margin of ostial opening (Fig. 5A); median lobe curved to the right apically in euventral view (Fig. 5B), the axis of apex nearly perpendicular to axis of median lobe base; internal sac with well-developed ventral microtrichial field but without distinct spicules; flagellar plate moderately large, length ⅓ distance from parameral articulation to distal surface of apex; parameres extended 0.82 × distance from parameral articulation to distal surface of apex.

Female reproductive tract. Bursa copulatrix broad basally, narrowed to apical third that extends as a narrow projection (Fig. 6A); bursal membrane thin, unwrinkled under microslide cover slip; spermatheca broadest in apical half, length 0.2 × length of sperma-thecal duct, duct joined to dorsal wall of bursa dorsad the basally broad common oviduct; spermathecal gland with orbicular reservoir, the reservoir about ½ length of duct which enters at base of spermatheca; membranous ramus at base of basal gonocoxite of usual length for Mecyclothorax spp. (e.g., Liebherr 2011, 2012), extended about ⅓ length of basal coxite (Fig. 7A); basal gonocoxite 1 with 3 apical fringe setae, medial surfaces from dorsal to ventral with about 8 very small setae; apical gonocoxite 2 narrow, apex subacuminate, with 2 lateral ensiform setae, the basal seta shorter and narrower than apical seta, 1 dorsal ensiform seta, and 2 short apical nematiform setae in small pitlike depression.

Holotype male (MNHN) labeled: French Polynesia: Tahiti Nui / Mt. Mauru trail at pylon 4 / el. 1060 m 5-IX-2006 lot 01 / 17°38.055'S, 149°22.146'W / pyr. fog mossy Metrosideros / & Melicope J.K. Liebherr // HOLOTYPE / Mecyclothorax / tihotii / J.K. Liebherr 2012 (black-bordered red label).

Allotype female (MNHN) labeled: French Polynesia: Tahiti Nui / Mt. Mauru trail at pylon 4 / el. 1060 m 5-IX-2006 lot 02 / 17°38.055'S, 149°22.146'W / beating flowering Myrsine & / Metrosideros J.K. Liebherr // ALLOTYPE … (same labeling as holotype).

Etymology.

Based on the extreme similarity of this species to Mecyclothorax ballioides , by which Georges Perrault honored Professor George E. Ball, the species epithet tihotii-Tahitian for George ( Wahlroos 2002)-is used. The epithet treats Tihoti, George, as a latinized second declension noun in the genitive singular.

Distribution and habitat.

The holotype was collected in a pyrethrin fog sample of moss-covered Metrosideros trunks (e.g., Fig. 2C) that served as nursery logs for Melicope plants. This specimen plus the holotype of Mecyclothorax putaputa comprised the entirety of carabid beetles from that sampled trunk. The female allotype was collected by beating Myrsine and mossy vegetation in the same area of low-stature forest, the allotype syntopic with two specimens of Mecyclothorax anaana .