Nylanderia brevisetula

Identification
LaPolla et al. (2011) - Head and mesosoma brown to reddish brown, with darker brown gaster; suberect setae on pronotum and mesonotum distinctly short.

Compare with: Nylanderia mendica

This is an unusual Nylanderia species with macrosetae on the pronotum and mesonotum both short and suberect. It may be confused with N. mendica, because N. brevisetula has a rugulose head similar to that of N. mendica and the macrosetae on the pronotum and mesonotum of N. mendica are also fairly short, though not as short as in N. brevisetula. N. mendica also has distinct striations both dorsally and ventrally on the gaster, whereas N. brevisetula only occasionally has faint striations dorsally on its gaster. Finally, N. mendica has a pronotum with lateral striations whereas N. brevisetula has a smooth pronotum laterally. We suspect based on the rugulose cuticles (generally an unusual condition in Nylanderia), similarly shaped heads, and the short macrosetae observed in both N. brevisetula and N. mendica that these two species are closely related.

Castes
The queen and male castes are currently unknown for this species.

Nomenclature

 *  brevisetula. Nylanderia brevisetula LaPolla & Fisher, in LaPolla, Hawkes & Fisher, 2011: 15, figs. 7-9, 75 (w.) GABON.

Worker
Measurements (n = 6): TL: 2.40–2.80; HW: 0.50–0.70; HL: 0.67–0.71; EL: 0.14–0.18; SL: 0.80–0.90; PW: 0.39–0.45; WL: 0.85–0.92; GL: 0.88–1.16

Indices: CI: 85–92; REL: 19–26; SI: 137–142

Head and mesosoma brown to reddish brown, with gaster dark brown, yellowish around acidopore; mandibles, antennae, trochanters, joints of legs and tarsi yellowish. Head rugulose; pronotum smooth and shining, with a few specimens faintly rugulose; gaster faintly striated; mesonotum, mesopleuron, and propodeum faintly rugulose in places. Posterior margin of head broadly rounded, with distinctly rounded posterolateral corners; medially posterior margin slightly emarginate. Scapes surpass posterior margin by about the length of the first 3–4 funicular segments; scapes with erect macrosetae (SMC ≥ 25) and an abundant layer of decumbent pubescence. Pronotum and mesonotum with scattered, distinctly short, erect to suberect macrosetae (PMC = 2–3; MMC = 2–4); pronotum gently rounded toward mesonotum; mesonotum distinctly rugulose; metanotal area elongate and rugulose; dorsal face of propodeum rounded, although lower than mesonotum; dorsal face shorter than declivitous face. Dorsally gastral segments with short, erect to appressed macrosetae, with macrosetae becoming slightly longer posteriorly; gaster with a layer of pubescence and appressed macrosetae.

Type Material
Holotype worker, GABON: Ogooue-Maritime: Aire d'Exploit. Rationnelle de Faune des Monts Doudou, 24.3 km 307° NW Doussala, 02°13'35"S 010°24'35" E, elev. 375 m, 6.iii.2000 (B.L. Fisher) (CASENT0179575); 6 paratype workers, same label data as holotype (CASC, )

Etymology
The species epithet brevisetula is a combination of brevi (L. = short) and seta (L. = bristle) with a Latin diminutive ending (ula), referring to the unusually short dorsal macrosetae of the workers.