Mecyclothorax poria, Liebherr, James K., 2013

Liebherr, James K., 2013, The Mecyclothorax beetles (Coleoptera, Carabidae, Moriomorphini) of Tahiti, Society Islands, ZooKeys 322, pp. 1-170 : 23-24

8. Mecyclothorax poria sp. n.

Diagnosis.

Of the four Mecyclothorax muriauxi group species with setal formula 1101 (Figs 11 B–D, 12A), this species exhibits the smoothest pronotal median base, which bears 5-8 rounded punctures along the gently sloped juncture with the pronotal disc, and only indistinct transverse wrinkles basally near the pronotal hind margin. The pronotum is broadest basally, the basal width subequal to the width at midlength (Fig. 11D). The eyes are small in diameter, ocular lobe ratio 0.74-0.81 (n = 5), but convex, ocular ratio 1.44-1.50. Standardized body length 5.1-6.2 mm. Head with broad, shallow frontal grooves, fine transverse wrinkles emanating from grooves onto frons; posterior supraorbital seta situated dorsad fine shallow groove lining juncture of ocular lobe and gena; antennae submoniliform, short, antennomere 8 length 1.69 × maximal breadth. Pronotum transverse, trapezoidal, the hind angles bluntly obtuse, the margin rounded behind, MPW/PL = 1.31-1.38; lateral margin straight anterad hind angle, but upraised and so appearing slightly sinuate; anterior transverse impression obsolete medially, narrow laterally where it is defined by a finely incised groove; front angles slightly protruded, rounded; lateral marginal depression narrow near midlength, edge beaded to just anterad hind angle. Elytra broad basally, humeri subangulate, lateral elytral margins convex (Fig. 11D); striae 1-5 evident, complete to basal groove, finely punctate in basal half and smooth apically, stria 6 shallower, stria 7 traceable as a series of isolated punctures basally, very shallow, obsolete apically, where it defines mesal border of slightly convex interval 8, that interval only indistinctly subcarinate apicad position of subapical sinuation; discal elytra intervals slightly convex; lateral elytral setae (6-7) + (5-6). Microsculpture obsolete on frons, indistinct isodiametric mesh on neck; pronotal disc with shallow transverse microsculpture, sculpticell breadth 2 –4× length; pronotal median base glossy, transverse mesh indistinct; discal elytral intervals covered with mixed elongate transverse mesh and transverse lines. Coloration of vertex rufous; antennomere 1 flavous, 2-3 brunneous with apex flavous, 4-11 darker, brunneous; pronotal disc rufous, the margins broadly rufoflavous; elytral disc rufous, marginal depression and humeral angle rufoflavous; femora flavous with brunneous cast, tibiae slightly more brunneous.

Male genitalia. Aedeagal median lobe blunt apically, with a broadly rounded, slightly convex ventral face and more pointed dorsal projection (Figs 3D, 13C); ostial canal straight, terminated just ventrad the dorsal projection. The five Mecyclothorax muriauxi group species for which males are known all possess similar median lobes, with Mecyclothorax poria , Mecyclothorax gerardi , and Mecyclothorax mapura exhibiting almost identical median lobe apices. The lobe apex of Mecyclothorax poria (Fig. 13C) is narrower dorsoventrally than that of Mecyclothorax mapura (Fig. 13D), and broader and more flattened apically than that of Mecyclothorax gerardi (Fig. 13B). Nevertheless, in these taxa, external characters can better distinguish the taxa.

Female reproductive tract. The bursa copulatrix of Mecyclothorax poria females is broadened basally, with no evidence of a discrete vagina (Fig. 14A). The bursa in the single known female has a smooth surface and a constriction just beyond midlength, and is approximately twice as long as its maximal breadth when compressed under a cover slip. The female basal gonocoxite exhibits an apical fringe of 3-4 setae (Fig. 8B), and approximately eight setae along the medial margin. The apical gonocoxite is broadened basally resulting in a broadly arcuate lateral margin. It bears two parallel-sided lateral ensiform setae, a dorsal ensiform seta, and an apical sensory furrow with two nematiform setae plus two furrow pegs.

Holotype female (MNHN) labeled: French Polynesia: Tahiti Nui / Mt. Marau road el. 1275 m / 10-IX-2006 lot 02 / 17°36.433'S, 149°32.339'W / pyr. fog horiz. Weinmannia / trunks + veg. J.K. Liebherr // HOLOTYPE / Mecyclothorax / poria / J.K. Liebherr 2013 (black-bordered red label).

Allotype female (MNHN) labeled: SOCIETY IS: Tahiti / Tahiti Nui Mont Marau / 1280 m el. 6-XI-1999 / D.A. Polhemus pyr. fog / sta. 1 Weinmannia for. // ALLOTYPE / Mecyclothorax / poria / J.K. Liebherr 2013 (black-bordered red label).

Paratypes: same data as allotype (CUIC, 2; NMNH, 1); Tahiti Nui, Mont Marau, Mt. Marau road, 1315 m el., 17°36.433'S, 149°32.333'W, 10-IX-2006 lot 05, Polhemus, pyr. fog mossy Weinmannia w/ Astelia (NMNH, 1)

Etymology.

The species epithet, poria, means fat or corpulent in Tahitian, the epithet signifying the broad outline of the body caused by the basally broadened pronotum and broadly based, laterally convex elytra.

Distribution and habitat.

All samples containing this species have come from the Mont Marau ridge between 1275 and 1315 m elevation. All specimens of the type series have been obtained by fogging moss-covered Weinmannia trees, in one instance when an Astelia plant was growing on the Weinmannia tree.