Key to Oriental Discothyrea

This key to workers of Oriental Discothyrea is based on Xu, Burwell & Nakamura (2014) as modified by Bharti, Akbar & Singh (2015).

1

Propodeal declivity more gradual, in lateral view, posterodorsal corner of propodeum rounded or very bluntly angled, forming an angle much greater than 90° => 2
Propodeal declivity abrupt, in lateral view, posterodorsal corner of propodeum narrowly to acutely toothed, forming an angle equal to or smaller than 90° => 5

Frontal carinae extending posteriorly to 2/3 length of head, anterior margin of clypeus crenulate. Malaysia; China: Hainan => Discothyrea bryanti
Frontal carinae only extending posteriorly to 1/2 length of head, anterior margin of clypeus not crenulate. India => Discothyrea periyarensis

In full-face view, posterior margin of head weakly convex, anterior clypeal margin straight. In lateral view, dorsum of mesosoma strongly convex, posterodorsal corner of propodeum forming an obtuse angle, propodeal lobes bluntly angled. Petiolar node relatively short and thin, height/length ratio = 2: 1 (LPI = 200). Japan => Discothyrea kamiteta
In full-face view, posterior margin of head straight, anterior clypeal margin weakly convex. In lateral view, dorsum of mesosoma weakly convex, posterodorsal corner of propodeum rounded, propodeal lobes rounded. Petiolar node relatively long and thick, height/length ratio = 1.7: 1 (LPI = 170 with range of 156–188). China: Yunnan => Discothyrea banna

Frontal area much longer than broad, roughly rhombic. Frontal carinae long and well separated, extending posteriorly to 1/2 to 2/3 of head-length => 6
Frontal area about as broad as long, roughly triangular, frontal carinae short and close to each other, extending posteriorly to about 1/3 of head-length => 8

Frontal carinae extending posteriorly to 2/3 of head-length. Anterior clypeal margin crenulate. In dorsal view, dorsum of petiolar node transversely depressed. Antennae 10-segmented. Total length about 3.1 mm. India => Discothyrea sringerensis
Frontal carinae extending posteriorly to 1/2 of head-length. Anterior clypeal margin not crenulate. In dorsal view, dorsum of petiolar node not transversely depressed. Antennae 8- or 9-segmented. Total length 1.5–1.8 mm => 7

In full-face view, head distinctly broader than long, posterior margin of head nearly straight. In lateral view, posterodorsal corner of propodeum acutely toothed, subpetiolar process elongate and higher than half its length. In dorsal view, petiolar node thin and scale-form, about 6 times as broad as long. Antennae 9-segmented. Total length about 1.5 mm. Indonesia => Discothyrea globa
In full-face view, head distinctly longer than broad, posterior margin of head weakly convex. In lateral view, posterodorsal corner of propodeum right angled, subpetiolar process short and about half its length. In dorsal view, petiolar node thick and node-form, about 3 times as broad as long. Antennae 8-segmented. Total length 1.6–1.8 mm. China; Taiwan; Japan => Discothyrea sauteri

In full-face view, posterior margin of head weakly concave medially. In dorsal view, dorsum of petiolar node transversely depressed. In lateral view, subpetiolar process large and roughly triangular. Antennae 7-segmented. China: Yunnan => Discothyrea diana
In full-face view, posterior margin of head weakly convex, not concave medially. In dorsal view, dorsum of petiolar node not transversely depressed. In lateral view, subpetiolar process small and short. Antennae 9-segmented => 9

In full-face view, head distinctly longer than broad with CI = 89, sides strongly convex. In lateral view, posterodorsal corner of propodeum forming a right angle, apex of propodeal lobes bluntly angled. Total length 1.5 mm. Bhutan => Discothyrea stumperi
In full-face view, head slightly broader than long with CI = 119, sides weakly convex. In lateral view, posterodorsal corner of propodeum forming an acute angle, apex of propodeal lobe rounded. Total length 1.7 mm. China; Taiwan => Discothyrea yueshen