Strumigenys natynion Bolton, 2000

Fig. 34A–C; Table 2

Strumigenys natynion Bolton, 2000: 762 (w.) BORNEO. Indomalaya.

Material examined

THAILAND – Sakon Nakhon Province • 2 workers; Site 104; 17.1326° N, 103.99685° E; 501 m a.s.l.; 21 Jun. 2018; IBBL members leg.; Winkler, 4 corners; IBBL ANTWEB1011940 to ANTWEB1011941 • 1 queen; Site 107; 17.12902° N, 104.00193° E; 484 m a.s.l.; 21 Jun. 2018; IBBL members leg.; Winkler, 4 corners; IBBL ANTWEB1011942 . • 1 worker; 17.1326° N, 103.99685° E; 501 m a.s.l.; 21 Jun. 2018; IBBL members legs. ANTWEB1011941; Winkler, 4 corners; IBBL .

VIETNAM – Đỗng Nai Province • 1 worker; Cat Tien National Park; 11.44912° N, 107.35963° E; 140 m a.s.l.; 4 Jun. 2018; IBBL members leg.; Winkler, 4 corners; IBBL • 2 workers; Cat Tien National Park; 11.48512° N, 107.38658° E; 168 m a.s.l.; 5 Jun. 2018; IBBL members leg.; Winkler, 4 corners; IBBL ANTWEB1011952 .

Measurements

Workers

TL 2.5–2.7, HL 0.62–0.71, HW 0.45–0.52, MandL 0.22–0.27, SL 0.31–0.36, EL 0.056 –0.060, PW 0.28– 0.30, ML 0.63–0.66, PL 0.28–0.30, PH 0.13–0.15, DPW 0.13–0.15, PPL 0.17, GL 0.57–0.61, CI 72–74, MI 35–38, SI 67–74, OI 12–13, LPI 45–51, DPI 46–52 (n =3).

Queen

TL 2.7, HL 0.63, HW 0.48, MandL 0.25, SL 0.34, EL 0.104, PW 0.31, ML 0.73, PL 0.27, PH 0.15, DPW 0.13, PPL 0.16, GL 0.65, CI 75, MI 40, SI 71, OI 22, LPI 54, DPI 48 (n= 1).

Geographic range

Malaysia (East Malaysia), Thailand (Sakon Nakhon), Vietnam (Đồng Nai).

New record for Thailand and Vietnam.

Ecology

Collected in secondary forest, with elevation from 140 to 501 m.

Comments

Specimens from Thailand and Vietnam all show a smaller preapical tooth, a slightly broader propodeal spine, a larger lateral lobe of the petiole (in both profile and dorsal views), relatively denser erect filiform to flagellate setae on the gaster than specimens from Borneo. They are also smaller (TL 2.5–2.7, HL 0.62–0.71, ML 0.63–0.66) than specimens from Borneo (TL 3.2–3.5, 0.88–0.94, ML 0.98) but retain similar body ratios (CI 72–74, Si 67–74 vs CI 68–74, SI 71–77). Bolton (2000) mentioned that the species appears plastic, with variations in pilosity and propodeal teeth. Hence, it is uncertain if the aforementioned morphological differences between specimens from Thailand and Vietnam on the one hand and those from Borneo on the other hand are geographical differences or an indication of a separate species. Based on the current species diagnosis, we consider material from Thailand and Vietnam as S. natynion .

The records in northern Thailand and southern Vietnam imply that the species is not endemic to Borneo, but instead may be more widespread in the Indochinese Peninsula. Its presence is likely in the other parts of the region, e.g., Peninsular Malaysia, Cambodia, Laos and Myanmar.