Key to Afrotropical Nylanderia workers

This worker key is based on: Lapolla, J. S., C. H. Hawkes, and B. L. Fisher. 2011. Monograph of Nylanderia (Hymenoptera: Formicidae) of the World, Part I: Nylanderia in the Afrotropics. Zootaxa. 3110:10-36.

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1

• Dorsal face of propodeum much shorter than declivitous face; in lateral view, propodeum lower than remainder of dorsum, dorsally angular or gently rounded . . . . . 2

• Dorsal face of propodeum distinctly rounded, about the same length as declivitous face; in lateral view, propodeum higher than or equal to remainder of dorsum, dorsally dome-like . . . . . 10

2

return to couplet #1

• Fewer than 10 erect macrosetae present on each scape . . . . . Nylanderia vividula

Head of Nylanderia vividula worker

Profile of Nylanderia vividula worker

• More than 10 erect macrosetae present on each scape . . . . . 3

3

return to couplet #2

• Dark brown color overall . . . . . 4

• Lighter yellow brown color overall . . . . . 6

4

return to couplet #3

• Mesopleuron with a dense layer of pubescence . . . . . Nylanderia bourbonica (see note "i" below)

Head of Nylanderia bourbonica worker

Profile of Nylanderia bourbonica worker

• Mesopleuron either without or with sparse pubescence . . . . . 5

5

return to couplet #4

• Dorsal face of propodeum gently rounded in profile; antennae and legs only slightly lighter than remainder of body . . . . . Nylanderia vaga (see note "i" below)

Head of Nylanderia vaga worker

Profile of Nylanderia vaga worker

• Dorsal face of propodeum very short with straight margin in profile; antennae and legs distinctly whitish-brown, sharply contrasting with remainder of body . . . . . Nylanderia umbella

Head of Nylanderia umbella worker

Profile of Nylanderia umbella worker

6

return to couplet #3

• Dorsal face of propodeum very short and angular . . . . . 7

• Dorsal face of propodeum gently rounded and convex . . . . . 8

7

return to couplet #6

• Mesocoxae and metacoxae lighter than procoxae . . . . . Nylanderia boltoni

Head of Nylanderia boltoni worker

Profile of Nylanderia boltoni worker

• Mesocoxae and metacoxae the same color as procoxae . . . . . Nylanderia scintilla

Head of Nylanderia scintilla worker

Profile of Nylanderia scintilla worker

8

return to couplet #6

• Macrosetae on pronotum abundant (PMC = 10–22); macrosetae on head, mesosoma and legs dark, contrasting strongly with the much lighter cuticle . . . . . Nylanderia usambarica

Head of Nylanderia usambarica worker

Profile of Nylanderia usambarica worker

• Macrosetae on pronotum not particularly abundant (PMC = 3–10); macrosetae on head, mesosoma and legs about the same color as cuticle . . . . . 9

9

return to couplet #8

• Southern Africa (Botswana, South Africa, Mozambique, and Zimbabwe) . . . . . Nylanderia natalensis (see note "ii" below)

Head of Nylanderia natalensis worker

Profile of Nylanderia natalensis worker

• Eastern, northern and western Africa . . . . . Nylanderia jaegerskioeldi (see note "ii" below)

Head of Nylanderia jaegerskioeldi worker

Profile of Nylanderia jaegerskioeldi worker

10

return to couplet #1

• Entire body dark brown, except for sharply contrasting, almost white protrochanters, mesocoxae and metacoxae . . . . . 11

• Body color variable, but if dark brown then mesocoxae and metacoxae are the same color as mesosoma . . . . . 12

11

return to couplet #10

• Head and mesopleuron cuticle smooth to sometimes slightly rugulose; head length between 0.53–0.68 mm; scape length between 0.60–0.81 mm . . . . . Nylanderia lepida

Head of Nylanderia lepida worker

Profile of Nylanderia lepida worker

• Head and mesopleuron cuticle distinctly rugulose; head length 0.70–0.80 mm; scape length between 0.91–0.98 mm . . . . . Nylanderia impolita

Head of Nylanderia impolita worker

Profile of Nylanderia impolita worker

12

return to couplet #10

• Gastral cuticular surface with distinct striations running lengthwise on dorsum; lateral portions of pronotum rugulose . . . . . Nylanderia mendica

Head of Nylanderia mendica worker

Profile of Nylanderia mendica worker

• Gastral cuticular surface smooth or with faint gastral cuticle striations; lateral portions of pronotum smooth . . . . . 13

13

return to couplet #12

• Mesosomal macrosetae very short . . . . . Nylanderia brevisetula

Head of Nylanderia brevisetula worker

Profile of Nylanderia brevisetula worker

• Mesosomal macrosetae not short . . . . . 14

14

return to couplet #13

• Body yellow, contrasting with darker erect setae, especially noticeable on the gaster . . . . . Nylanderia luteafra

Head of Nylanderia luteafra worker

Profile of Nylanderia luteafra worker

• Body color variable, but erect setae not conspicuously darker than remainder of body . . . . . 15

15

return to couplet #14

• Head, mesosoma and gaster a solid dark reddish-brown; scape length between 0.95–1.04 mm . . . . . Nylanderia silvula

Head of Nylanderia silvula worker

Profile of Nylanderia silvula worker

• Head, mesosoma and gaster yellowish-brown; scape length between 0.74–0.8 mm . . . . . Nylanderia incallida

Head of Nylanderia incallida worker

Profile of Nylanderia incallida worker

i - These species are thought to be introduced species to the Afrotropical region. The species boundaries of bourbonica and vaga are poorly defined and are being revised by JSL and others. One species, N. vividula, is reported from the Afrotropics, but we have not seen specimens of this species from the region. Males would be particularly useful because they have distinctive genitalia, unlike any African species. We include this species in the key because past reports have noted its presence in the Afrotropics.

ii - Workers of natalensis and jaegerskioeldi cannot be reliably identified to species. However, males of the two species can be easily distinguished. Geographically, natalensis appears to be restricted to southern Africa and jaegerskioeldi is found in East, North and West Africa.