Mecyclothorax toretore, 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 : 75-77

4. Mecyclothorax toretore sp. n. Figs 4A8C

Diagnosis.

This species shares fully striate elytra and transversely-lined elytral microsculpture with Mecyclothorax fuscus Perrault. Both species are also characterized by presence of only the anterior dorsal elytral seta and only the apical elytral seta; setal formula 2111. However, this species differs by: 1, the very narrow elytra with subparallel lateral margins versus more ovoid elytra in Mecyclothorax fuscus ; and 2, the laterally extended humeri resulting in a MEW/HuW ratio of 1.89 in this species, versus MEW/HuW = 1.97 for Mecyclothorax fuscus . The pronotal hind angles are also profoundly margined in this species (Fig. 4A), with the lateral and basal marginal beads defining a U-shaped pronotal laterobasal depression. Conversely, the hind angles are upraised but without a distinctly beaded margin in Mecyclothorax fuscus . Standardized body length is 4.2 mm for this species versus 4.0 mm for Mecyclothorax fuscus .

Description.

Head capsule withlinear, slightly convergent frontal grooves, broad and shallow at frontoclypeal suture, terminated posteriorly mesad thin carina inside anterior supraorbital seta; neck slightly depressed between two pairs of supraorbital setae, depression visible dorsally (Fig. 4A); ocular lobe moderately protruded, hind margin joining gena at 135° angle, juncture marked by narrow, shallow groove; ocular ratio 1.34, ocular lobe ratio 0.88; labral anterior margin nearly straight, emarginated <0.1 × length; antennomeres 1-3 glabrous except for apical setae, pore sensilla visible in the translucent cuticle; antennae elongate, filiform, antennomere 8 length 2.29 × maximal breadth; mentum tooth sides defining acute angle, apex narrowly rounded. Pronotum subquadrate, MPW/PL = 1.14, base constricted with distinctly sinuate lateral margins anterad sharply projected, nearly right hind angles, MPW/BPW = 1.46; median base moderately depressed relative to disc, 14-16 regular punctures each side; basal margin slightly convex between laterobasal depressions; median longitudinal impression very fine and shallow on disc, indistinct transverse wrinkles emenating onto disc anteriorly, lenticular depression at front of median base; anterior transverse impression very broad, very shallow medially, impression incised in outer half of breadth each side; anterior callosity slightly convex, crossed with numerous fine longitudinal wrinkles; front angles slightly protruded, broadly rounded laterally; front angles closer together than hind angles, APW/BPW = 0.90; lateral marginal depression very narrow laterally, slightly wider at front angle, margin beaded throughout, bead broad at sinuate basolateral margin; surface of U-shaped laterobasal depression sparsely lined with minute micropunctures; prosternal process distinctly beaded laterally between procoxae, medially convex between beads. Elytra narrowly subparallel, MEW/HuW = 1.89; disc slightly convex toward apical ⅓ of suture, sloped toward sides but ninth interval visible in dorsal view; basal groove broadly curved to point basad stria 5, then distinctly curved anterad to angulate humerus; parascutellar seta present, situated near sutural stria; parascutellar striole 4-5-punctate, striole shallow between shallow punctures; sutural interval broadly upraised to suture basally, narrower with similar convexity apically, therefore appearing more callouslike; striae 1-6 minutely punctate in basal ⅓, punctures associated with strial irregularities, striae 5-6 obsolete basally; intervals 2-5 moderately convex on disc; striae 1-4 plus 7 deep apically, striae 5-6 shallow but traceable; eighth interval broadly convex from midpoint of posterior lateral setal series to apex; 1 dorsal elytral seta situated at 0.26 × elytral length, seta situated in deep, evident depression that spans ¾ width of interval 3; apical elytral seta present, subapical seta absent; lateral elytral setae 7 + 5; elytral marginal depression narrow, margin little upturned at humerus, margin slightly explanate outside anterior lateral setal series, beadlike in posterior half; subapical sinuation broad, shallow. Mesepisternum with about 16 punctures in 2-3 vertical rows; metepisternum slightly elongate, width to length ratio 0.79; metepisternum separated from metepimeron by distinct suture. Abdomen with visible ventrites 1-3 irregularly wrinkled laterally, ventrites 3-6 with rounded depressions laterally; suture between visible ventrites 2 and 3 complete. Legs somewhat foreshortened, metatarsomere 1 length 0.17 × metatibial length; metatarsomere 4 slightly emarginated apically, overall length 1.2 × median tarsomere length; metatarsomere 4 with apical and subapical setae; metatarsal dorsolateral sulci shallow and lateral, tarsomere median surface broadly convex. Microsculpture of head an indistinct transverse mesh, sculpticell breadth 2 –3× length, surface glossy; pronotal disc with transverse mesh, sculpticell breadth 2 –4× length, mixed with transverse lines; pronotal median base with shallow transverse mesh, sculpticell breadth 2 × length among the punctures; elytral disc with well-developed transverse lines, only occasional cross-connections, surface subiridescent; elytral apex with a mixture of transverse mesh, sculpticell breadth 2 –4× length, and transverse lines; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse scultpicells. Coloration of head capsule dark rufous, clypeus rufoflavous; antennomeres 1-2 rufoflavous, antennomere 3 slightly darker, 4-11 rufobrunneous; pronotal disc dark rufous; pronotal margins and median base paler, rufous; proepipleuron rufoflavous, proepisternum dark rufous; elytral disc dark rufous with piceous cast in apical ⅓; sutural interval rufous basally, pale rufous apically; elytral marginal depression concolorous with disc at humerus, lateral marginal depression paler, rufoflavous laterally and apically; elytral epipleuron rufoflavous dorsally, more brunneous ventrally, metepisternum rufobrunneous; abdomen rufobrunneous medially, visible ventrites 1-3 with piceous cast laterally; apical ¼ of apical visible abdominal ventrite paler, rufoflavous; metafemur flavous; metatibia flavous with darker carina associated with longitudinal setal series.

Female reproductive tract.- The unique female holotype was not dissected, although the gonocoxae were exposed allowing their preliminary characterization (Fig. 8C). Basal gonocoxite 1 with angulate apical margin, the margin angled toward base along lateral half of apical gonocoxite 2; basal gonocoxite with apical fringe of 2 setae; apical gonocoxite 2 distinctly convergent in basal half of length, apical half more narrowly convergent to subacuminate tip, with 2 lateral ensiform setae and 1 dorsal ensiform seta that extends medially-and is thus visible in ventral view-and 2 apical nematiform setae.

Holotype female (MNHN) labeled: French Polynesia: Tahiti Nui / Mt. Mauru cloud for. 1080 / m el. 20-IX-2006 lot 03 / 17°37.916'S, 149°22.318'W / pyrethrin fog fern frond / tangles C.P. Ewing // HOLOTYPE / Mecyclothorax / toretore / J.K. Liebherr 2012 (black-bordered red label).

Etymology.

The Tahitian word toretore means striped, as in striped cloth ( Wahlroos 2002). The word’s use as the species epithet signifies the deep, distinct elytral striae, and is to be used as a noun in apposition.

Distribution and habitat.

The lone specimen of this species was found in the highest, wettest rain forest sampled-1080-1100 m elevation-during a tropical rainstorm, the use of a hand-held pyrethrin fog canister over a beating sheet the sole collecting method of any utility under those conditions. That the beetle plus those of Mecyclothorax tutei and Mecyclothorax pirihao were found in dead fern tangles during this storm suggests that the beetles had moved into such tight quarters due to the rain. Neither Mecyclothorax tutei nor Mecyclothorax toretore were collected during drier conditions in this elevational band of forest even though extensive beating of vegetation had been undertaken over the course of three days.