Mecyclothorax tutei, 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 : 66-69

1. Mecyclothorax tutei sp. n. Figs 3A8A

Diagnosis.

Most similar to Mecyclothorax cooki Perrault, sharing: 1, moderately transverse pronotum, MPW/PL = 1.25; 2, straight to slightly sinuate pronotal lateral margin anterad obtusely rounded hind angle; 3, well-indicated parascutellar striole; 4, transverse-mesh elytral microsculpture; 5, two dorsal elytral setae; and 6, convex elytral intervals. Both species are characterized by a 2221 setal formula, however the pronotal hind angles are more rounded in Mecyclothorax tutei (Fig. 3A) and the pronotal base more constricted; MPW/BPW = 1.42 for Mecyclothorax tutei , versus 1.37 for Mecyclothorax cooki . Standardized body length is somewhat smaller in Mecyclothorax tutei ; 5.3 mm versus 5.7 mm for Mecyclothorax cooki .

Description.

Head capsule withshallow frontal grooves, broad and obliquely wrinkled posteromedially near clypeus, transversely wrinkled medially on frons, with low rounded convexity laterally near antennal base, and thin carina mesad anterior supraor bital seta; vertex transversely depressed between posterior margin of eyes, depression visible in dorsal view; ocular lobe broadly convex, moderately protruded, meeting gena at> 135° angle, juncture marked by narrow groove that is carinate behind; ocular ratio 1.46, ocular lobe ratio 0.78; labral anterior margin nearly straight, medially emarginated <0.1 × length; antennomeres 1-3 glabrous except for apical setae; antennae filiform, antennomere 8 length 2.0 × maximum breadth; mentum tooth sides defining an acute angle, apex tightly rounded. Pronotum moderately transverse, MPW/PL = 1.25, with narrower base, MPW/BPW = 1.42; setose hind angles obtusely rounded, lateral margins briefly, indistinctly sinuate anterad minutely projected margin at seta, basal margin convexly rounded posterad seta causing jag in margin; median base distinctly depressed relative to disc, ~13 punctures medially each side plus rugose wrinkles laterally; basal margin slightly convex between laterobasal depressions; median longitudinal impression broad, moderately deep with finely incised center, fine transverse wrinkles emenating laterally onto disc; anterior transverse impression very broad and shallow medially, crossed by numerous, distinct longitudinal wrinkles, finely incised and smooth in lateral half of breadth each side; anterior callosity as depressed as transverse impression medially, crossed by longitudinal wrinkles; front angles very slightly protruded, broadly rounded, closer together than hind angles, APW/BPW = 0.89; lateral marginal depression narrow in apical half, edge upturned, broadened in basal half to broad, explanate margin laterad laterobasal depression; laterobasal depression broadly expanded from lateral depression, surface with small punctures mesally at disc, broadly raised lateral margin transversely wrinkled; proepisternum with 5 broad punctures along granulate hind margin, proepimeron with granulate hind margin; prosternal process broad, lateral margins broadly beaded, slightly depressed medially between procoxae. Elytra broadly ovoid, disc convex, upraised above scutellum, sides moderately sloped to 75° angle at marginal depression; basal groove distinctly arcuate forward to tightly rounded, proximate humeral angles, MEW/HuW = 2.39; parascutellar seta present; parascutellar striole shallow, smooth, continuous; sutural interval convex, similar to striae 2-4 basally, narrower and more upraised apically; discal striae 2-6 broadly, moderately convex, smooth, slightly wavering along length; striae 1-8 of subequal depth at elytral apex, stria 2 slightly shallower, irregular; eighth interval upraised, bulging from apex to point laterad juncture of striae 5 + 6; two dorsal elytral setae in deep, evident depressions that extend only ½ width of interval 3, the setae at 0.26 –0.27× and 0.54 –0.57× elytral length; apical elytral seta present, subapical seta absent; lateral elytral setae 7 + 6; subapical sinuation very shallow, elongate, most impressed at posterior end of posterolateral setal series. Mesepisternum lined with about 24 punctures in 3-4 vertical rows; metepisternum short, width to length ratio 0.86; metepisternum separated from metepimeron by distinct suture. Abdomen with visible ventrites 1-5 irregularly wrinkled laterally, ventrites 4-6 with rounded lateral depressions; suture between visible ventrites 2 and 3 effaced laterally. Legs gracile, metatarsomeres elongate, metatarsomere 1 length 0.215 × metatibial length; metatarsomere 4 emarginated apically, overall length 1.4 × median tarsomere length, apical setae present, subapical setae very short (or perhaps broken in the single type specimen); metatarsal dorsolateral sulci shallow, lateral, tarsomeres broadly convex medially. Microsculpture of head distinct, frons covered with a mixture of isodiametric and transverse meshes; pronotal disc with shallow, evident transverse mesh, sculpticell breadth 2 –4× length; pronotal median base with isodiametric mesh swirling among punctures; elytral disc covered with distinct transverse mesh microsculpture, sculpticell breadth 2 –3× length, mixed with transverse lines; elytral apex with mixture of isodiametric and transverse mesh, the transverse sculpticells twice as broad as long; metasternum covered with transverse mesh; laterobasal abdominal ventrites covered with swirling isodiametric and transverse sculpticells. Coloration of head capsule rufobrunneous with piceous cast in frontal grooves; antennomeres 1-2 rufoflavous, 3-11 rufobrunneous; pronotal disc rufobrunneous, pronotal margins slightly paler on edge of disc, darker, rufopiceous on explanate lateral margins; proepipleuron rufoflavous anterad, rufobrunneous posterad, proepisternum brunneous; elytral disc rufobrunneous with silvery metallic reflection; sutural interval rufous basally, rufoflavous apically; elytral lateral marginal depression rufoflavous; elytral apex broadly, slightly paler, rufoflavous at apex; elytral epipleuron rufoflavous, metepisternum rufobrunneous; visible abdominal ventrites 1-3 rufobrunneous, 4-6 rufoflavous; metafemur rufoflavous; metatibia rufoflavous with brunneous cast.

Female reproductive tract. The unique female holotype was not dissected, although the gonocoxae were exposed allowing their preliminary characterization (Fig. 8A). Basal gonocoxite 1 broad apically, with apical fringe of 3-4 setae; apical gonocoxite 2 broad basally, stout, with tightly rounded apex, 2 lateral ensiform setae and 1 dorsal ensiform seta (visible through gonocoxite in ventral view (Fig. 8A), 2 apical nematiform setae in round pitlike depression.

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 / tutei / J.K. Liebherr 2012 (black-bordered red label).

Etymology.

The species epithet honors Captain James Cook who named the Society Islands after the Royal Society, at whose behest he observed the 1769 transit of Venus from Tahiti. The epithet is his last name in Tahitian, Tute ( Wahlroos 2002), treated as a latinized second declension noun in the genitive singular; tutei.

Distribution and habitat.

The lone specimen of this species was found in tangles of living and dead fern fronds in low-stature wet montane Weinmannia and Metrosideros forest at 1080 m elevation. The beetle was collected from a beating sheet held under fronds that were sprayed with synthetic pyrethrin. The single specimen of Mecyclothorax toretore and a series of Mecyclothorax pirihao were also found using this method at this elevation.