Protanilla

Hsu, Po-Wei, Hsu, Feng-Chuan, Hsiao, Yun & Lin, Chung-Chi, 2017, Taxonomic notes on the genus Protanilla (Hymenoptera: Formicidae: Leptanillinae) from Taiwan, Zootaxa 4268 (1), pp. 117-130 : 129

Key to the world fauna of Protanilla based on the worker-caste

(Modified from Xu 2012, Bharti & Akbar 2015)

1. Mandibles with a large convex dorsal lamella and a large longitudinal groove on outer surface.................................................................................................. P. izanagi Terayama, 2013 (Japan)

- Mandibles thin, long and narrowly triangular, without a dorsal lamella; with or without a groove on outer surface.........2

2. Lateral or ventral margin of mandibles with 1–2 denticles. Postpetiole broadly attached to abdominal segment IV.........3

- Lateral and ventral margin of mandibles smooth, without denticle. Postpetiole narrowly attached to abdominal segment IV..4

3. Ventral faces of mandibles with only one inconspicuous denticle. Anterior margin of abdominal segment IV in dorsal view slightly concave. Side of abdominal segment IV with a deep and narrow notch between the tergite and sternite at the anterior margin. In profile view, postpetiolar sternite nearly straight, and anterior corner forming a right angle.................................................................................................... P. jongi sp. nov. (Taiwan)

- Lateroventral margins of mandibles armed with 2 distinct teeth (one long and one short). Anterior margin of abdominal segment IV in dorsal view deeply concave. Side of abdominal segment IV without a deep and narrow notch between the tergite and sternite at the anterior margin. In profile view, postpetiolar sternite deeply concave...................................................................................... P. furcomandibula Xu, 2002 rev. comb. ( China: Yunnan)

4. In full face view, anterior margin of clypeus strongly concave. In dorsal view, petiole distinctly longer than broad. Body bicolored, the middle portion black, the rest brownish yellow.......................................................5

- In full-face view, anterior margin of clypeus straight to weakly concave. In dorsal view, petiole as broad as long or broader than long. Body concolorous, uniformly yellowish brown or reddish brown........................................6

5. In full-face view, anterior 1/3 of the head distinctly narrowed. In profile view, anterior and dorsal faces of petiolar node somewhat differentiated, meeting at a broadly rounded angle. Head brownish yellow. Body small (HW 0.42–0.45 mm in types).......................................................................... P. bicolor Xu, 2002 ( China: Yunnan)

- In full face view, anterior half of head distinctly narrowed. In profile view, petiolar node evenly rounded, with no differentiation of anterior and dorsal faces. Head light black to blackish brown. Body large (HW 0.60–0.65 mm in types)................................................................................... P. gengma Xu, 2012 ( China: Yunnan)

6. In profile view, anterior face of petiole distinctly concave, anterodorsal corner protruding............................7

- In profile view, anterior face of petiole straight, sloped or slightly convex.........................................8

7. Petiole distinctly broader than long, slightly widened posteriorly. In profile view, top half of postpetiole slightly inclined anteriorly and roughly round......................................... P. rafflesi Taylor, 1990 (Singapore and Malaysia)

- Petiole nearly square in dorsal view, as broad as long, weakly narrowed posteriorly. In profile view, top half of postpetiole roughly rectangular, with straight anterior and posterior face..................... P. wardi Bharti & Akbar, 2015 (India)

8. Top half of postpetiole not inclined forward, posterodorsal corner angled. In dorsal view, both petiole and postpetiole round, as long as broad................................................................ P. lini Terayama, 2009 (Taiwan)

- Top half of postpetiole strongly inclined forward. In dorsal view, at least petiole or postpetiole compressed anteroposteriorly, broader than long......................................................................................9

9. In full face view, anterolateral corners of head prominent and tooth-like. In profile view, petiole relatively thick and roughly trapezoidal, dorsal face long, approximately as long as anterior face..................... P. tibeta Xu, 2012 ( China: Tibet)

- In full face view, anterolateral corners of head smooth and without prominent tooth-like structures. In profile view, petiole relatively thin and roughly triangular, dorsal face short, approximately half the length of anterior face............................................................................................ P. concolor Xu, 2002 ( China: Yunnan)