Nylanderia boltoni

Identification
LaPolla et al. (2011) - Head width less than 0.48 mm; yellowish-brown to brown species, with very short, angular propodeal dorsal face; mesocoxae and metacoxae lighter than procoxae in color.

Compare with: Nylanderia scintilla and Nylanderia umbella

This species is most likely to be confused with N. umbella and N. scintilla. It can be separated from N. umbella by the fact that N. umbella is a much darker brown species, with distinctly contrasting yellowish-brown mesocoxae and metacoxae. The distinction between Nylanderia boltoni and N. scintilla can be more difficult, but in N. scintilla the coxae are the same color.

Distribution based on Regional Taxon Lists
Afrotropical Region: Gabon, South Africa, Uganda.

Nomenclature

 *  boltoni. Nylanderia boltoni LaPolla & Fisher, in LaPolla, Hawkes & Fisher, 2011: 14, figs. 1-3, 73, 89-91 (w.m.) GABON.

LaPolla et al. (2011) - LaPolla et al. (2011) - This species has one of the widest ranges of any Afrotropical Nylanderia (the other being N. jaegerskioeldi) being found in West, East and South Africa. Given this large range, spanning several bioclimatic regions, there are some questions as to conspecificity, but the workers from all regions are morphologically very similar to each other, with minor variations noted in color. Males are only known from the Ghana specimens (which were in particularly poor condition) and more collecting of nest series from across the species range would be informative.

Worker
Measurements (n = 4): TL: 1.8–2.3; HW: 0.40–0.47; HL: 0.52–0.61; EL: 0.12–0.15; SL: 0.52–0.64; PW: 0.29–0.37; WL: 0.56–0.69; GL: 0.76–1.0

Indices: CI: 77–81; REL: 22–25; SI: 121–136

Overall yellowish brown, with lighter brown to yellow mandibles, antennae, and legs; head and gaster typically darker brown than mesosoma, although in some specimens the mesosoma is the same color as the head and gaster, or just the anterior portion of the pronotum is the same color; cuticle smooth and shining; coxae may be entirely yellowish-brown in color; in some specimens mesocoxae and metacoxae slightly lighter in color than procoxae. Head with a dense layer of pubescence; scapes surpass posterior margin by about the length of the first two funicular segments; scapes with scattered erect macrosetae and a dense layer of pubescence (SMC = 13–16); posterior margin with rounded posterolateral corners, slightly emarginate medially. Mesosoma with erect macrosetae of varying lengths concentrated on posterior pronotum and mesonotum (PMC = 2–4; MMC = 2–4); pubescence scattered across mesosomal notum; metanotal area compact; dorsal face of propodeum angular and low (lower than mesonotum) with very short dorsal face and longer declivitous face; propodeal dorsum with pubescence; declivity smooth and shining with no pubescence. Gaster with erect macrosetae and a dense layer of pubescence.

The queen caste is currently unknown for this species.

Male
Measurements (n = 1): TL: 2.0; HW: 0.48; HL: 0.48; EL: 0.22; SL: 0.56; PW: 0.42; WL: 0.78; GL: 0.78 Indices: CI: 100; REL: 45; SI: 117

Overall head and gaster light brown, with lighter brown to yellowish-brown antennae, mesosoma, tibia and tarsi; cuticle smooth and shining with short appressed pubescence on head, dorsal mesosoma and gaster with slightly longer pubescence. Compound eyes strongly convex (more than half the length of the lateral margin), with raised ocelli. Scapes surpass posterior margin by about length of first four funicular segments; scapes with sparsely scattered erect macrosetae (SMC = 2–4) and short appressed pubescence. Mandible with small, but distinct, apical tooth, margin emarginate behind, followed by a small, indistinct denticle; basal angle distinct. Mesosoma with short, appressed pubescence and scattered erect macrosetae (PMC = 0; MMC = 7–9) dorsally; dorsal face slightly sloped, well below level of mesonotum; dorsal face and declivitous face about the same length. Gaster with longer pubescence than on mesosoma and scattered suberect and erect macrosetae. Genitalia: parameres broadly rounded at apices curving dorsally (such that they obscure some of the genitalia in dorsal view); apical margin of parameres emarginate; ventral margin of parameres at an acute angle; cuspi elongated, apices rounded with peg-like teeth on ental surface where they meet digit; digiti apices broad; peg-like teeth at apices dorsally, ventrally coming to a narrow point that curves towards parameres.

Type Material
Holotype worker, GABON: F.C. Mondah, 21 km 331° NNW Libreville, 00°34'36" N, 009°20'06" E, elev. 10 m; 24.ii.1998 (B.L. Fisher) (CASENT0179580); 1 paratype worker, same label data as holotype ; 1 paratype worker, CENTRAL AFRICAN REPUBLIC: P.N. Dzanga-Nodki, 21.4km 53 NE Bayanga, 3 02.01’N, 16 24.57’E, 510 m, 1–7.v.2001 (S. van Noort) (USNM).

Etymology
Named to honor Barry Bolton (retired – Natural History Museum, London) for his truly exceptional contributions to ant systematics and for his kind support of JSL and BLF over the years. It seems to us especially fitting to name an African ant species after Barry because he has contributed enormously to our understanding of African ant systematics through his many publications on the topic.