Mecyclothorax oaoa, Liebherr, James K., 2013

Liebherr, James K., 2013, The Mecyclothorax beetles (Coleoptera, Carabidae, Moriomorphini) of Tahiti, Society Islands, ZooKeys 322, pp. 1-170 : 98-99

82. Mecyclothorax oaoa sp. n.

Diagnosis.

Of the four Tahitian Mecyclothorax globosus group species with two supraorbital setae each side and no dorsal elytral setae, setal formula 2101 (Figs 41A, Figs 42 A–C), this species can be diagnosed by the narrow, subquadrate elytra and the impressed and distinctly punctate discal elytral striae (Fig. 42A). The pronotum is only slightly transverse - MPW/PL = 1.14 - and basally constricted; MPW/BPW = 1.52. The eyes are moderately small, leaving the posterior fifth of the protruded ocular lobe uncovered; ocular ratio = 1.43, ocular lobe ratio 0.82. Standardized body length 3.7 mm. Head with convex frons, frontal grooves linear, convergent anteriorly, with transverse wrinkles radiating onto frons from grooves; anterior and posterior supraorbital setae proximate, separated by 3 × the diameter of the depression housing the anterior seta; antennae short, nearly moniliform, antennomere 8 length 1.5 × maximal breadth. Pronotum cordate, lateral margins concavely convergent for short distance anterad projected, obtuse hind angles, the distinct angle filled with a triangularly raised bead; median base sloped upward to meet convex disc, moderately depressed, with ~14 deep punctures each side, the punctures elongate along discal margin; anterior transverse impression broad, shallow, more defined laterally along anterior margin posterad slightly convex anterior callosity, fine longitudinal wrinkles lining impression laterally; front angles slightly protruded, very tightly rounded; lateral marginal depression narrow, edge beaded, depression broader inside front angles but beaded margin as high there as laterally; laterobasal depression a shallow extension of the discal base, smooth unilaterally, irregularly rugose on other side of type specimen. Elytra moderately convex, the sides gently sloped to the lateral marginal depression; discal surface between intervals 1-4 appearing flat each side (single specimen has crumpled elytra), sutural interval raised as a median callous; discal striae 1-5 moderately convex, punctate, the elongate punctures slightly enlarging strial breadth, striae 6-7 smoother, surface undulated along length; striae 1-7 variously shallower basally than on disc or obsolete for short distance posterad elytral basal groove; humeri distinctly angulate, basal groove evenly curved, MEW/HuW = 1.97; eighth interval subcarinate laterad stria 7, upraised above stria from subapical sinuation to apex; lateral elytral setae 7 + 6. Microsculpture of frons an evident transverse mesh, sculpticell breadth 2.0 × length, neck with evident isodiametric mesh; pronotal disc with shallow but evident transverse mesh, sculpticell breadth 2 –4× length; discal elytral intervals lined with well-developed transverse microsculpture including areas of transverse mesh, sculpticell breadth 2 –4× length, and transverse lines. Coloration of head dark rufous, clypeus and labrum rufoflavous; antennomeres 1-3 rufoflavous, 4-11 rufobrunneous; pronotal disc dark rufous to match frons, lateral margin depression narrowly, median base broadly, rufous; elytral disc rufobrunneous with silvery metallic reflection; sutural interval rufous basally, rufoflavous apically, lateral marginal depression narrowly brunneous; femora rufoflavous, tibiae rufoflavous with brunneous cast.

Holotype female (MNHN) labeled: French Polynesia: Tahiti Iti / Mts. Teatara NW ridge / 1146 m el. 19-IX-2006 lot 09 / 17°47.855'S, 149°14.266'W / pyr. fog moss log C.P. Ewing / HOLOTYPE / Mecyclothorax / oaoa / J.K. Liebherr 2013 (black-bordered red label).

Etymology.

The species epithet is the Tahitian word oaoa, meaning narrow, the name signifying the narrowly ovate elytra characterizing this species.

Distribution and habitat.

The type specimen was found on Mont Teatara, Tahiti Iti in Weinmannia forest at 1150 m elevation. The specimen was collected by applying pyrethrin fog to a mossy log upon which grew a mature Astelia plant with numerous dead leaves. Two specimens of Mecyclothorax globosoides were also collected in this sample.