Mecyclothorax fuscus Perrault, 1989: 62

Liebherr, James K., 2013, The Mecyclothorax beetles (Coleoptera, Carabidae, Moriomorphini) of Tahiti, Society Islands, ZooKeys 322, pp. 1-170 : 107-108

90. Mecyclothorax fuscus Perrault, 1989: 62

Identification.

Very much like the preceding two species, Mecyclothorax niho and Mecyclothorax toretore sharing setal formula 2111 (Figs 45C, D, 46A), but deviating from the former by the more elongate sinuation of the pronotal lateral margin, the margin convergent outside the laterobasal depression (Figs 45C, 46A), and from the latter by the broadly ovate elytra; MEW/HuW = 1.97 versus 1.89 in Mecyclothorax toretore (Figs 45D, 46A). The pronotum is also more transverse than observed in specimens of the other two species, with MPW/PL = 1.20 verus 1.12 in Mecyclothorax niho and 1.14 in Mecyclothorax toretore . This species can also be diagnosed by the smoother discal elytral striae that are irregular along their length but are not distinctly punctate in their deepest portions. Finally, known specimens of this species are smaller than those of the other two species; standardized body length here 3.6 mm, versus 4.1-4.2 mm for the other two species. The frons and vertex bear a shallow transverse mesh that is visible through the reflected shine of the microscope light, and the pronotal disc is covered with an evident transverse mesh, sculpticell breadth 2 –4× length.

Distribution and habitat.

The two type and only known specimens of this species were collected near the summit of Mont Aorai at 1900m elevation.