Mecyclothorax papuhiti, Liebherr, James K., 2013

Liebherr, James K., 2013, The Mecyclothorax beetles (Coleoptera, Carabidae, Moriomorphini) of Tahiti, Society Islands, ZooKeys 322, pp. 1-170 : 78-79

65. Mecyclothorax papuhiti sp. n.

Diagnosis.

Among the five species currently known to comprise this group, this one has the least transverse pronotum (Fig. 35A), MPW/PL = 1.18, in company with evenly explanate lateral margins that are narrower than those characterizing Mecyclothorax gourvesioides and Mecyclothorax gourvesi (Figs 35 B–D). Also, though the elytral lateral margin is broad outside the anterior series of lateral elytral setae, it is narrow and opaque immediately laterad the humeral angle. The male holotype of this species is also smaller than individuals of the other species in the group; standardized body length 4.8 mm versus 5.0-6.2 mm for specimens of the other four species. Setal formula 2122. Head with deep, canaliculate frontal grooves, posteriorly bordered laterally mesad eye by robust, convex carina, anteriorly bordered laterally by broadly sinuous convexity; eyes convex on protruded ocular lobe, ocular ratio 1.52, ocular lobe meeting gena at distinct groove, ocular lobe ratio 0.82; antennae elongate, segments filiform, antennomere 8 length 2.0 × maximal breadth. Pronotum with distinctly sinuate lateral margins before nearly right hind angles, the basal margin slightly convex behind laterobasal depression; median base moderately depressed relative to disc, with ~24 small but distinct punctures on each side, the punctures separated by smooth cuticle; anterior transverse impression obsolete medially, sharply incised in lateral 2/3 of each side, without longitudinal wrinkles; front angles slightly protruded anteriorly, broadly rounded; lateral margins broadly and evenly upturned, slightly broader inside front angles; laterobasal depression a deep, linear extension of the deepest portion of lateral marginal depression, with about three indistinct, irregularities mesad lateral sinuation. Elytra broadly ovate, lateral margins curved posteriorly outside obtuse-angulate humeri; disc convex relative to depressed scutellum and lateral margins; striae 1-5 well defined to basal groove, distinctly punctate on disc, the round punctures expanding strial breadth, stria 6 shallower with punctures more elongate, and stria 7 shallower still, interrupted in places with punctures forming elongate dashes; interval 8 convex, bulging laterally along posterior series of lateral elytral setae to its apex, its mesal margin forming a long subcarinate ridge adjacent to stria 7; lateral elytral setae 7 + 6. Microsculpture absent on frons and vertex, the cuticle glossy; pronotal disc with obsolete transverse mesh microsculpture, sculpticell breadth 2 –3× length, the sculpticells visible only near edges of fields of reflected light; discal elytral intervals lined with evident transverse lines intermixed with areas of transverse mesh, sculpticell breadth 3 × length. Coloration of frons and vertex dark rufous, clypeus rufous, labrum rufoflavous; antennomere 1 flavous, 2-3 rufoflavous, 4-11 rufobrunneous; pronotal disc slightly darker than head, base rufous and lateral margins rufoflavous; elytral disc concolorous with head, sutural interval rufous basally, rufoflavous apically; elytral lateral marginal depression and apices of elytral intervals 7-9 near posterior lateral elytral setae rufoflavous, inner intervals also rufoflavous beyond level of subapical sinuation.

Male genitalia. Aedeagal median lobe shaft narrow and of even diameter from parameral articulations to apex of ostium, barely narrower apically with an evenly propor tioned dorsoventrally spatulate apex (Fig. 36C); ostial canal short and close to dorsal margin of lobe; internal sac not everted, but spiculate fields not evident inside lobe shaft.

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 // HOLOTYPE / Mecyclothorax / papuhiti / J.K. Liebherr 2013 (black-bordered red label).

Etymology.

The species epithet pahuhiti compounds the Tahitian words pāpū, meaning even, with hiti, meaning border or edge, the species name signifying the evenly explanate pronotal lateral margins.

Distribution and habitat.

The single known specimen was collected in a beating sample along with one specimen of Mecyclothorax gourvesi and three specimens of Mecyclothorax kayballae . These microsympatric collections from dead tree fern fronds along a wet rock face demonstrate that: 1, Mecyclothorax pahuhiti shares ecological space with the more abundant and geographically widespread species group member, Mecyclothorax gourvesi ; and 2, sampling a wet rock face and associated vegetation resulted in the discovery of two new species. Neither newly described species has been found at any other time in any other ecological situation. Additionally, specimens of three other species - Mecyclothorax ballioides , Mecyclothorax globosus , and Mecyclothorax ovalipennis - were also present in this sample, demonstrating that a diverse array of Mecyclothorax species can occupy this microhabitat at a single site.