Key to Asian species of Parasyscia

This key to Asian species of Parasyscia based on the worker caste is modified from Chen et al. (2022).

Note. This key follows Bharti & Akbar (2013) and treats Parasyscia keralensis as a species inquirenda, therefore it is not included.

1

 * Eye degenerate, small, its maximum diameter smaller than or equal to the width of basal funicular segment, not breaking the lateral margins of head (Fig. 1A–B)
 * Eye large and protruding, its maximum diameter two times more than the width of basal funicular segment, breaking lateral margins of head (Fig. 1C–D)

2

 * Mid-dorsal portion of mesosoma smooth and shiny, without puncta (Fig. 2A)
 * Mid-dorsal portion of mesosoma punctate (Fig. 2B)

3

 * Maximum diameter of eye equal to the basal width of scape; ventral margin of subpetiolar process straight; in lateral view petiolar node subrectangular, the front and the back parallel (Fig. 3A) Parasyscia wittmeri
 * Maximum diameter of eye smaller than the basal width of scape; ventral margin of subpetiolar process concave; in lateral view petiolar node trapezoid, with top narrower than bottom (Fig. 3B) Parasyscia piochardi

4

 * Lateral surface of head and mesosoma densely and coarsely reticulate (Fig. 4A)
 * Lateral surface of head and mesosoma smooth and shiny, or with small, sparse puncta, interspaces between puncta smooth and shiny (Fig. 4B)

5

 * In lateral view, anterodorsal corner of petiolar node angular, level with posterodorsal corner; in dorsal view, petiole subrectangular, lateral margins parallel (Fig. 5A–B) Parasyscia reticulata
 * In lateral view, anterodorsal corner of petiolar node rounded, and lower than posterodorsal corner; in dorsal view, petiole trapezoid, broader posteriorly (Fig. 5C–D) Parasyscia hashimotoi

6

 * Antennae 12-segmented Parasyscia wighti
 * Antennae 11-segmented Parasyscia ganeshaiahi

7

 * In lateral view, petiole trapezoid, anterior and posterior faces convex (Fig. 6A–B)
 * In lateral view, petiole subrectangular, anterior and posterior faces flat, parallel (Fig. 6C–D)

8

 * Abdomen clearly concolorous (Fig. 7A)
 * Abdomen clearly bicolored (Fig. 7B)

9

 * Body dark reddish-brown; in lateral view, dorsal outline of mesosoma strongly convex; in dorsal view, anterolateral margin of first gastral segment relatively more convex (Fig. 8A–B) Parasyscia muiri
 * Body light yellow; in lateral view, dorsal outline of mesosoma slightly convex; in dorsal view, anterolateral margin of first gastral segment relatively less convex, tapering more evenly to juncture with third abdominal segment (Fig. 8C–D) Parasyscia shii

10

 * In full-face view, head rounded, posterolateral corner broadly rounded (Fig. 9A) Parasyscia fossulata
 * In full-face view, head subrectangular, posterolateral corner narrowly rounded or clearly angular (Fig. 9B–C)

11

 * In full-face view, posterior margin of head slightly convex, posterolateral corner narrowly rounded (Fig. 9B); head with tiny piligerous puncta; posterodorsal margin of propodeum without carina; if carina present, it is extremely degraded (Fig. 10A) Parasyscia rufithorax
 * In full-face view, posterior margin of head strongly concave, posterolateral corner clearly angular (Fig. 9C); head with coarse puncta; posterodorsal margin of propodeum with strong carina (Fig. 10B) Parasyscia tibetana

12

 * Abdomen clearly bicolored (Fig. 11A)
 * Abdomen concolorous or nearly so (Fig. 11B–C)

13

 * In lateral view, posterodorsal corner of propodeum rounded; mesosoma and petiole with shallow puncta (Fig. 12A) Parasyscia aitkenii
 * In lateral view, posterodorsal corner of propodeum angular; mesosoma and petiole with deep puncta (Fig. 12B) Parasyscia wilsoni

14

 * In full-face view, center of head with longitudinal groove, almost reaching to the posterior margin of the head (Fig. 13A) Parasyscia conservata
 * In full-face view, center of head without longitudinal groove (Fig. 13B)

15

 * In dorsal view, petiole longer than wide (Fig. 14A) Parasyscia indica
 * In dorsal view, petiole broader than long (Fig. 14B)

16

 * In full-face view, the front of head with a wide and deep arc-shaped groove (Fig. 15A) Parasyscia kodecorum
 * In full-face view, the front of head without a wide and deep arc-shaped groove (Fig. 15B)

17

 * In full-face view, head coarsely and densely punctate, margins of puncta partially connected to reticulation (Fig. 16A–B)
 * In full-face view, head smooth and shiny, or, if punctate, with margins of puncta not connected to reticulation (Fig. 16C–D)

18

 * In lateral view, petiolar node higher than long (Fig. 17A) Parasyscia foveolata
 * In lateral view, petiolar node longer than high (Fig. 17B)

19

 * In full-face view, posterolateral corner of head angular; in dorsal view, tergite of postpetiole with scattered shallow puncta (Fig. 18A–B) Parasyscia nigrita
 * In full-face view, posterolateral corner of head rounded; in dorsal view, tergite of postpetiole rugoso-reticulate (Fig. 18C–F)

20

 * The mid-dorsal portion of mesosoma with confluent puncta; posterior face of propodeum rugose (Fig. 19A) Parasyscia browni
 * The mid-dorsal portion of propodeum with separated puncta; posterior face of propodeum smooth and shiny (Fig. 19B) Parasyscia dohertyi

21

 * Small size (TL ≤ 2 mm) Parasyscia bryanti
 * Large size (TL > 2.8 mm)

22

 * In full-face view, posterior margin of head distinctly concave, posterolateral corner forming prominent lobe; the maximum diameter of eye larger than the maximum diameter of the apical funicular segment; body black (Fig. 20A–B) Parasyscia salimani
 * In full-face view, posterior margin of head straight, posterolateral corner not forming prominent lobe; the maximum diameter of eye slightly smaller than or equal to the maximum diameter of the apical funicular segment; body yellow to dark brown (Fig. 20C–D)

23

 * In lateral view, posterodorsal margin of propodeum rounded; anterodorsal corner of petiole lower than posterodorsal corner; in dorsal view, posterodorsal margin of propodeum without carina (Fig. 21A–B) Parasyscia luteoviger
 * In lateral view, posterodorsal margin of propodeum angular; anterodorsal corner of petiole and posterodorsal corner at the same level; in dorsal view, posterodorsal margin of propodeum with carina (Fig. 21C–D)

24

 * Petiole slightly broader than long, PI=114–116; head subrectangular, lateral margins parallel (Fig. 22A–B) Parasyscia schoedli
 * Petiole distinctly broader than long, PI >140; head lateral margins converging anteriorly and posteriorly (Fig. 22C–D)

25

 * Eye small, its maximum diameter equal to the width of base of scape (Fig. 23A) Parasyscia seema
 * Eye large, its maximum diameter almost two times more than width of the base of scape (Fig. 23B–C)

26

 * Lateral mesosoma with small puncta, their maximum diameter smaller than the diameter of spiracle of propodeum; declivity of propodeum straight (Fig. 24A–B) Parasyscia rifati
 * Lateral mesosoma with large puncta, their maximum diameter equal to or larger than the diameter of spiracle of propodeum; declivity of propodeum concave (Fig. 24C) Parasyscia xui