Nylanderia

Brady, Seán G. & Shattuck, Steven O., 2011, Monograph of Nylanderia (Hymenoptera: Formicidae) of the World: An introduction to the systematics and biology of the genus, Zootaxa 3110, pp. 1-9 : 4-5

Description of Nylanderia

The following genus description is modified from Trager (1984). Habitus views of all three castes are provided in Fig. 1. Workers are generally monomorphic although some species are variable in size, with a possible example of worker polymorphism observed in N. amblyops from Madagascar.

Workers:

— Small to medium sized (generally between 1.0–4.0 mm in total length [defined as: head length + Weber length + gaster length]) formicine ants ranging in color from pale yellow to black; cuticle usually smooth and shining, but sculpturing present in several African species.

— Mandibles typically with 6 or, rarely, 7 teeth present; palp formula 6:4 except in N. dodo which is 5:3. For an example of a typical Nylanderia mandible, labium, and maxillae see Fig. 3.

— Clypeus subrectangular, medially convex, with scattered erect setae.

— Antennae 12-segmented; scapes surpass posterior margin of head; scapes with erect macrosetae and a layer of pubescence.

— Eyes usually well developed (although small-eyed species are known), placed midlength or anterior and laterally on head; ocelli often absent, but when present, indistinct.

— Sides of head parallel or gently convex, merging into broadly rounded posterior corners.

— Posterior margin straight or medially convex.

— Pronotum typically broadly convex ( Fig. 4); in lateral view, pronotal margin convex and then leveling off towards the mesonotal margin; in a few species pronotal margin nearly flat in lateral view ( Fig. 4E); macrosetae on pronotum variable, although often with two pairs of long erect macrosetae and scattered shorter erect setae.

— Mesonotum typically flat to slightly convex; mesonotum with scattered erect macrosetae (often with two pairs of long erect macrosetae and scattered shorter erect setae).

— Propodeum shape variable ( Fig. 4); dorsal face can be slightly convex but fairly short ( Fig. 4A), short and angular ( Fig. 4B), or strongly convex and dome-like ( Fig. 4C); propodeum always lacking erect macrosetae, although a fringe of pubescence often present on anterior of propodeum (one known exception, an undescribed species from Papua New Guinea, Fig. 4D).

— Legs with abundant, scattered macrosetae.

— Petiole wedge-shaped (cuneate), never surpassing the height of the propodeum in lateral view, although in some species it approaches height of propodeum.

— Gaster large and oval shaped, becoming pointed distally towards acidopore; usually with abundant, scattered erect macrosetae and often a layer of pubescence.

— Petiolar foramen long, extending beyond the anteriormost points of the metacoxal cavities.

Queens:

— Generally as in worker with modifications expected for caste.

— Eyes large and conspicuous, with three well developed ocelli.

— Mandibles with 6 or, rarely, 7 teeth present.

— Scapes generally shorter relative to head length than observed in conspecific workers.

— Typically most of cuticle covered in a dense layer of pubescence; scattered macrosetae found on scapes, head, pronotum, mesonotum, legs and gaster; general body color often darker than workers.

— Mesosoma large, with collar-like pronotum and overarching mesonotum.

— Mesonotum large and flat, typically with scattered macrosetae.

— Propodeum typically with short, subangular dorsal face, even in species with a long dorsal face in the worker. — Gaster very large, with scattered macrosetae.

Males:

— Sculpture and color pattern of males generally approaching those of workers.

— Mandibles well developed with a prominent apical tooth and often a small, basal tooth (or just a pronounced basal angle), with smaller denticles present along masticatory margin in some species.

— Scapes long, surpassing posterior margin of head; antennae 13-segmented.

— Eyes large and conspicuous, with three well developed ocelli.

— Mesosoma large, with collar-like pronotum and overarching mesonotum.

— Mesonotum large and flat, typically with scattered macrosetae.

— Propodeum inconspicuous, with very short dorsal face.

— Genitalia prominent; parameres often subtriangular in appearance; digiti and cuspi highly variable; 9 th sternite often obscured by 8 th sternite in which case it is only visible with dissection.