Mecyclothorax niho, Liebherr, James K., 2013

Liebherr, James K., 2013, The Mecyclothorax beetles (Coleoptera, Carabidae, Moriomorphini) of Tahiti, Society Islands, ZooKeys 322, pp. 1-170 : 106-107

88. Mecyclothorax niho sp. n.

Diagnosis.

This comprises one of the three species within the Mecyclothorax globosus group that are characterized by two supraorbital setae each side and one dorsal elytral seta - setal formula 2111 - plus subquadrate elytra, the lateral margins subparallel at midlength (Figs 45C, D, 46A). However this species can be diagnosed from the other two, Mecyclothorax toretore and Mecyclothorax fuscus , by the narrow pronotum, MPW/PL = 1.12, with very briefly sinuate lateral margins anterad the obtuse, little-projected, denticulate hind angles, and by the elytral striae that are deep and continuous to their juncture with the elytral basal groove. Standardized body length 4.1 mm. Head with broad and shallow frontal grooves, the mesal surface undulated and transversely wrinkled at midlength, broadly depressed anteriorly near frontoclypeal suture; eyes moderately convex, covering much of ocular lobe, ocular ratio 1.45, ocular lobe ratio 0.93; antennae moderately elongate, submoniliform, antennomere 8 length 1.75 × maximal breadth. Pronotum narrow, subquadrate; median base slightly depressed relative to disc, 16-17 punctures each side, the punctures rounded on base, more elongate along margin with disc; anterior transverse impression broad, shallow, smooth medially, finely incised in outer third of breadth each side; frontal angles protruded, tightly rounded; lateral marginal depression narrow, margin beaded, broader and with lower bead inside front angles; laterobasal depression an expansion of the lateral depression with ~5 small punctures over the surface. Elytra broadest in basal half, lateral margins broadly rounded outside angulate humeri; disc moderately convex, sides moderately sloped to lateral marginal depression; striae 1-7 deep, continuous, with small micropunctures at depth on disc, the punctures not expanding strial breadth; discal elytral intervals moderately convex; all striae well impressed apically, depth of stria 2 subequal to depth of sutural stria 1; eighth interval subcarinate laterad stria 7 dorsad subapical sinuation to apex, the interval convexly bulging laterally; lateral elytral setae 7 + 6. Microsculpture of frons an obsolete transverse mesh, the elongate sculpticells more visible in association with transverse wrinkles, neck glossy; pronotal disc with shallow transverse mesh, sculpticell breadth 2 –4× length; discal elytral intervals covered by transverse lines with little tendency to form an elongate mesh. Coloration of frons dark rufous, clypeus and labrum rufoflavous; antennomere 1 flavous, 2-3 plus base of 4 rufoflavous, remainder of antennae rufobrunneous; pronotal disc dark rufous to match head, depression inside front angle and median base paler, rufoflavous and rufous respectively; elytra rufous with silvery metallic reflection, the sutural interval slightly paler near scutellum, rufoflavous apically to match pale elytral apex; femora flavous, tibiae flavous with rufobrunneous cast.

Holotype female (MNHN) labeled: French Polynesia: Tahiti Iti / Mts. Teatara NW ridge 1080- / 1100 m el. 17-IX-2006 lot 07 / 17°47.778'S, 149°14.339'W / pyrethrin fog mossy logs of / Weinmannia J.K. Liebherr // HOLOTYPE / Mecyclothorax / niho / J.K. Liebherr 2013 (black-bordered red label).

Etymology.

The species epithet niho is the Tahitian word for tooth, the name referring to the denticulate pronotal hind angles.

Distribution and habitat.

This species has been recorded from near 1100 m elevation, Mont Teatara, Tahiti Iti. The pyrethrin fog sample from a moss-covered Weinmannia log also included specimens of Mecyclothorax bryobioides , Mecyclothorax globosoides , and Mecyclothorax laevilateralis .