Key to the females of Zigrasimecia

Notes: Z. tonsora and Z. goldingot, described based on queens, are tentatively included in the key based on their head and metasomal characters. Any mesosomal character mentioned in the key must not be considered if the keyed specimen is a queen.

1. The specimen is a gyne: mesosoma is complex, having discernible mesoscutum and mesoscutellum and clear divisions between the sclerites......................................................................................... 2

- The specimen is a worker: mesosoma is compact and simplified, most sclerites are fused and indiscernible.............. 3

2. [Triplet] With the following combination of characters: More than 30 clypeal chaetae. Petiole having a distinct anterior, dorsal, and posterior surfaces; dorsal surface appearing flat (Fig. 1, B of Barden & Grimaldi, 2013). Head having short, fine setae on frons and vertex which are progressively longer posterad. Frons with a V-shaped shallow groove. Propodeum dorsal surface long (Fig. 2, A and B of Barden and Grimaldi, 2013)........................... Z. tonsora Barden & Grimaldi, 2013

- With the following combination of characters: Less than 25 clypeal chaetae. Petiole node apex brief, not forming a distinct dorsal surface. In anterolateral (or posterolateral) views of the petiole, apex of node bilobed. Setation on body mostly of decumbent small setae. Frons without grooves. Propodeum dorsal surface short (micro-CT scan image by Yuhui Zhuang available at Antweb under specimen YKLP-AMB-001)............................. Z. goldingot Zhuang et al., 2022

- Without the above two combinations. From now on, run your queen specimen in the key without considering mesosomal characters whenever mentioned......................................................................... 3

3. Abundant and conspicuous standing setae on dorsum of head, mesosoma, and metasoma. Setae varying in morphology (Figs. 6, 8, 11)............................................................................................ 4

- Conspicuous standing setae on body absent or restricted to dorsum of head. Body mainly glabrous, at most covered by very small, appressed, setae (Figs. 7, 8, 12, 13)................................................................. 7

4. Standing setae on body thin and filiform (Figs. 6, 9)......................................................... 5

- Standing setae on body thick, tip of individual seta truncate and sometimes slightly clavate (Fig. 14).............................................................................................. Z. hoelldobleri Cao e t al., 2020

5. Setae on body sparse, relatively short, erect (not flexuous). Tip of petiolar node truncate. Cinctus on abdominal segment IV weak, but discernible (Fig. 11)....................................................... Z. ferox Perrichot, 2014

- Setae on body flexuous and relatively long, usually abundant. Tip of petiolar node either round and without paired protrusions (Fig. 10, D) or thin (barely forming a dorsal surface) and with a pair of protrusions (Fig. 6 D). Cinctus on abdominal segment IV vestigial to absent.................................................................................. 6

6. Mesosoma extremely compact, "chubby". Frontal carina vestigial, merely a soft oblique bump between the torulus and the eye. Tip of petiolar node round. Head in full-face view round, with poorly differentiated lateral and vertexal margins. Eyes with less than 100 ommatidia (Fig. 9).......................................................... Z. chuyangsui sp. nov.

- Mesosoma not particularly compact. Frontal carina conspicuous. Tip of petiolar node with a pair of protrusions. Head in full-face view subrectangular, having distinct lateral and vertexal margins. Eyes with more than 150 ommatidia (Fig. 6)........................................................................................... Z. boudinoti sp. nov.

7. Dorsum of head, at the frontal and vertexal areas, with a conspicuous patch of setae which can be raised and long, and flagellate or short, decumbent and curved.......................................................................... 8

- Dorsum of head without a patch of specialized setae......................................................... 9

8. Long, subflagellate, looped setae on dorsum of head. Head in full-face view almost as long as broad (Fig.13)................................................................................................... Z. thate sp. nov.

- Short, curved, and decumbent setae on dorsum of head. Head in full-face view slightly longer than wide (Fig. 20)............................................................................................. Zigrasimecia ufv-11

9. Head in full-face view subrectangular. In profile, propodeal dorsal and posterior (descending) margins distinct. Medium-sized species (TL 2.86) (Fig. 12).............................................................. Z. perrichoti sp. nov.

- Head in full-face view round. In profile, propodeal dorsal and posterior (descending) margins softly merge into each other. Small species (TL 2.25) (Fig. 7)........................................................ Z. caohuijiae sp. nov.