Nannophyopsis chalcosoma

A very small libellulid dragonfly characterized by a slender, spindle-shaped abdomen with segments 5–9 progressively widened, producing a weakly clubbed appearance. General coloration glossy black with strong metallic green to bronzy reflections on frons, thorax, and abdomen. Frons metallic green with coppery reflections; eyes chestnut-brown. Thorax short and narrow, predominantly black with metallic green sheen dorsally and slight coppery reflections laterally. Wings hyaline; basal area of hind wing suffused with golden-yellow coloration. Pterostigma elongate, narrow, greyish-brown. Male distinguished by comparatively large and projecting secondary genitalia; superior appendages slender, nearly straight in dorsal view, slightly incurved apically; inferior appendages broad basally, tapering distally and slightly upturned apically. Female generally similar to male but larger and more robust, with broader wings and more extensive golden-yellow basal wing coloration. Nannophyopsis chalcosoma differs from related small Libellulidae by the combination of minute body size, metallic black coloration, narrow thorax, distinctly spindle-shaped abdomen, elongate pterostigma, and reduced anal field of the hind wing.