Key to Platythyrea of southeast Asia

This key to species Southeast Asian Platythyrea is based on Phengsi et al. (2018) and Jaitrong et al. (2022).

1

 * Frontal carinae very widely spaced, not continuing beyond level of posterior margin of antennal insertions (Fig. 7A); propodeal spiracle opening circular
 * Frontal carinae relatively narrowly separated, extending far beyond level of posterior margin of antennal insertions where space between them is very narrow (Fig. 7B); propodeal spiracle opening elliptical

2

 * In dorsal view, posterior margin of petiole with 2 or 3 distinct spines, teeth or blunt angles (Fig. 8A, B)
 * In dorsal view, posterior margin of petiole without distinct spines, teeth or sharp angles (Fig. 8C)

3

 * In dorsal view, posterior margin of petiole clearly concave with distinct lateral blunt angles; in profile view, petiole almost as long as high
 * In dorsal view, posterior margin of petiole with 3 distinct spines; in profile view, petiole longer than high (Fig. 8B) Platythyrea tricuspidata

4

 * In full-face view, head oval, almost as long as broad, posterior margin broadly convex (Fig. 8A); in profile view, posterodorsal corner of petiole nearly right angle (Fig. 7F) Platythyrea sagei
 * In full-face view, head subrectangular, slightly longer than broad, posterior margin broadly almost straight or weakly concave (Fig. 8B); in profile view, posterodorsal corner of petiole bearing truncate spine (Fig. 7G)

5

 * In profile view, propodeum armed with a pair of short teeth or tubercles (Fig. 9); in profile view, lateral face of pronotum punctate, with dense foveae; lateral face of petiole wrinkled; in profile view, dorsal outline of petiole roundly convex (Fig. 7H) Platythyrea quadridenta
 * In profile view, propodeum unarmed; in profile view, lateral faces of pronotum and petiole rather smooth, without foveae; in profile view, dorsal outline of petiole almost straight or weakly convex (Fig. 7G) Platythyrea bidentata

6

 * In full-face view, head elongate (CI < 77), posterior margin deeply concave Platythyrea nicobarensis
 * In full-face view, head elongate (CI > 77), posterior margin shallowly concave

7

 * In dorsal view, petiole clearly longer than broad; antennal scape relatively short, not reaching posterolateral corner of head Platythyrea parallela
 * In dorsal view, petiole almost as long as broad; antennal scape relatively long, slightly extending beyond posterolateral corner of head Platythyrea inermis

8

 * Lateral face of head and pronotum punctate, with dense foveae (Fig. 5A1); antennal scape relatively short (SI = 125–138); smaller species (TL 5.74–6.20; HW 0.86–0.89); eye with 5 or 6 ommatidia on longest axis Platythyrea clypeata
 * Lateral face of head and pronotum finely micopunctate (Figs 5B1, 5C1); antennal scape relatively long (SI > 150); larger species (TL 7.59–7.80; HW 1.06–1.12)

9

 * Head narrower posteriorly (Fig. 3B). Dorsal outline of petiole weakly convex, posterior margin of petiolar node without a concavity in the middle (Fig. 7E). Body surface with thin pubescence (Fig. 3A). Eyes with 7 or 8 ommatidia on longest axis (Fig. 5B2) Platythyrea homasawini
 * Head not narrower posteriorly (Fig. 4B). Dorsal outline of petiole almost straight, posterior margin of petiolar node with a concavity in the middle. Body surface with thick pubescence (Fig. 4A). Eyes with 9–11 ommatidia on longest axis (Fig. 5C2) Platythyrea janyai