Key to Protanilla species

This key to workers of Protanilla is based on Satria et al. (2023), which is a modification of keys by Hsu et al. (2017), Man et al. (2017) and Baidya & Bagchi (2020).

It does not include Protanilla schoedli as it was described from a single damaged queen.

1

Mandibles with a large convex dorsal lamella and a large longitudinal groove on outer surface. Japan. => Protanilla izanagi

Griebenow (2024), Figure 35. Anterior of the worker head in Protanilla, full-face view. A, Protanilla izanagi (CASENT0842850). B, Protanilla jongi (CASENT0842693). Scale bars: 0.1 mm.

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

2

return to couplet #1

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

return to couplet #2

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. Taiwan. => Protanilla jongi

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. China: Yunnan. => Protanilla furcomandibula

4

return to couplet #2

With head 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

return to couplet #4

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 relatively small (HW 0.42–0.45 mm). China: Yunnan. => Protanilla bicolor

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 relatively large (HW 0.60–0.65 mm). China: Yunnan. => Protanilla gengma

6

return to couplet #4

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

return to couplet #6

Petiole distinctly broader than long, slightly widened posteriorly. In profile view, top half of postpetiole slightly inclined anteriorly and roughly round. Singapore and Malaysia. => Protanilla rafflesi

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 faces. India: Kerala. => Protanilla wardi

8

return to couplet #6

Top half of postpetiole not inclined forward, posterodorsal corner angled. In dorsal view, both petiole and postpetiole round, as long as broad. => 9
Top half of postpetiole strongly inclined forward. In dorsal view, at least petiole or postpetiole compressed anteroposteriorly, broader than long. => 10

9

return to couplet #8

Scape exceeds posterior margin of head (SI 104.167). Taiwan. => 9a
Scape does not extend beyond posterior margin of head (SI 90.986). India: Goa. => Protanilla flamma

9a

In profile view petiolar node relatively higher with bluntly angled anterodorsal corner. Dorsum of postpetiolar node moderately convex, subpostpetiolar process longer with anteroventral corner rounded. Body size smaller with TL 2.9 and HL 0.60. Body color yellowish brown. China: Taiwan Province. => Protanilla lini

In profile view petiolar node relatively lower with rounded anterodorsal corner. Dorsum of postpetiolar node almost straight, subpostpetiolar process longer with anteroventral corner rounded. Body size larger with TL 3.9 to 4.0 and HL 0.65 to 0.70. Body color reddish brown, posterior half of mesothorax and metathorax black. China: Beijing. => Protanilla beijingensis

10

return to couplet #8

In profile view, petiole relatively thin and roughly triangular, dorsal face short, approximately half the length of anterior face. China: Yunnan. => Protanilla concolor

In profile view, petiole relatively thin and roughly triangular, dorsal face short, approximately half the length of anterior face. => 11

11

return to couplet #10

Body much smaller (TL 2.7 mm). Head in full face view, anterolateral corners of head prominent and tooth-like. Petiole in lateral view with its ventral outline of subpetiolar process

almost straight. China: Tibet. => Protanilla tibeta

Body much larger (TL 5.15–5.47 mm). With head in full face view, anterolateral corners without prominent tooth-like structures. Petiole in lateral view with its ventral outline of subpetiolar process sinuate. Indonesia: Sumatra. => Protanilla eguchii

Satria et al., 2023, Figure 1. Protanilla eguchii, holotype, worker (individual code: SEMUT-13viii22A, colony code: SAGO-4viiI): A — head in full-face view; B — habitus in profile.
Satria et al., 2023, Figure 2. Protanilla eguchii, holotype, worker (individual code: SEMUT-13viii22A, colony code: SAGO-4viiI): A — mesosoma in lateral view; B — petiole and postpetiole in lateral view; C — mesosoma in dorsal view; D — petiole and postpetiole in dorsal view.

References