Key to Nylanderia of the West Indies

This worker key is based on: LaPolla, J.S. and R.J. Kallal. 2019. Nylanderia of the World Part III: Nylanderia in the West Indies. Zootaxa. 4658(3):401–451. (doi:10.11646/zootaxa.4658.3.1).

LaPolla and Kallal considered the West Indies as being the islands of the Greater and Lesser Antilles and the Lucayan Archipelago.

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1

• Extremely small eyes (REL <15); body yellow to orange-yellow . . . . . 2
• Eyes not small (REL ≥ 20); body color variable, often with contrasting lighter and darker regions . . . . . 4

2

return to couplet #1

• Mesosoma covered in abundant macrosetae (PMC: 24–27; MMC: 5–10) (Puerto Rico) . . . . . Nylanderia microps

• Mesosoma not covered in abundant macrosetae (PMC <5; MMC <4) . . . . . 3

3

return to couplet #2

• Propodeal dorsal face long (relative to declivitous face) and relatively flat; SI2: 7–9 (Cuba) . . . . . Nylanderia myops

• Propodeal dorsal face short (relative to declivitous face) and distinctly convex; SI2: 11–14 (Trinidad) . . . . . Nylanderia zaminyops

4

return to couplet #1

• Most of mesosoma covered with abundant pubescence . . . . . 5

• Spare to no pubescence present on mesosoma, or if abundant pubescence present on any areas of mesosoma then it is not present on mesopleuron or lateral portions of propodeum . . . . . 6

5

return to couplet #4

• Body reddish-brown to yellow; REL less than 30; mesosomal macrosetae long (index of longest pronotal macrosetae/propodeum height at least least 60) . . . . . Nylanderia fulva or Nylanderia pubens ++

Paratrechina fulva

Paratrechina pubens

• Body dark brown to almost black; REL greater than 30; mesosomal macrosetae short (index of longest pronotal macrosetae/ propodeum height less than 60) . . . . . Nylanderia bourbonica

6

return to couplet #4

• Strongly bicolored; head and gaster, and in one species the pronotum, distinctly darker than mesosoma . . . . . 7

• Not strongly bicolored; head and gaster not different in color from mesosoma . . . . . 8

7

return to couplet #6

• Head and gaster dark brown, mesosoma bright yellow; macrosetae dark brown to black; SL typically >0.68 mm (Dominican Republic) . . . . . Nylanderia disatra

• Head, pronotum, and gaster brown; mesosoma mostly yellow, anterior mesonotum often brown, propodeum often bright yellow; macrosetae brown; SL <0.68 mm (Puerto Rico) . . . . . Nylanderia semitincta

8

return to couplet #6

• In lateral view, under light microscope examination bright blue iridescence observed on the cuticular surface of the body, especially on the mesopleuron, but also often on lateral and dorsal portions of head and dorsum of the gaster; first and second gastral tergites pubescent (Dominican Republic) . . . . . Nylanderia caerula

• In lateral view, under light microscope examination bright blue iridescence not observed on the cuticular surfaces of the body or if faint blue iridescence observed then first and second gastral tergites not pubescent . . . . . 9

9

return to couplet #8

• Mandibular subbasal tooth (tooth immediately following basal tooth) relative to both basal and median teeth large (e.g., the tooth is about as large as the teeth on either side of it); pale yellow to brownish yellow species; SMC: 22–32 (Lucayan Archipelago) . . . . . Nylanderia lucayana

• Mandibular subbasal tooth (tooth immediately following basal tooth) relative to both basal and median teeth small (e.g., the tooth is distinctly smaller than teeth on either side of it); color variable but if subbasal tooth large relative to both basal and median teeth then color is dark brown; if yellow to brownish yellow then SMC less than 22 . . . . . 10

10

return to couplet #9

• Gastral tergite I without pubescence; if present it sparsely covers the posterior half of tergite . . . . . 11

• Gastral tergite I covered entirely by a fine pubescence . . . . . 14

11

return to couplet #10

• SL > 0.9, HL > 0.74; propodeal dorsal face with a distinct convex dome-like shape (Trinidad) . . . . . Nylanderia goeldii

• SL < 0.87, HL < 0.74; propodeal dorsal face without a distinct convex dome-like shape . . . . . 12

12

return to couplet #11

• Dorsal face of propodeum usually with a distinct fringe of pubescence; SL 0.8–0.86; gastral tergite I pubescence absent on anterior end of segment becoming denser midlength to dense towards posterior end; mesosomal dorsum with pubescence, especially on mesonotum (Dominican Republic) . . . . . Nylanderia pini

• Dorsal face of propodeum without a fringe of pubescence; SL < 0.78; gaster without pubescence or with very scattered and sparse pubescence not in pattern described above; mesosomal dorsum without pubescence . . . . . 13

13

return to couplet #12

• Meso/metacoxae and petiole distinctly lighter in color than mesosoma and gaster; typically lower SMC (measured range: 18–24; average count 23) (Dominican Republic) . . . . . Nylanderia fuscaspecula

• Meso/metacoxae and petiole not distinctly lighter in color than mesosoma and gaster; typically higher SMC (measured range: 22–30; average count 27) (Cuba) . . . . . Nylanderia xestonota

14

return to couplet #10

• Propodeal dorsal face distinctly convex; SMC typically less than 20 (measured range: 12–23) . . . . . 15

• Propodeal dorsal face not distinctly convex; dorsal face flattened in lateral view; SMC typically greater than 20 (measured range: 18–38) . . . . . 17

15

return to couplet #14

• Body and legs bright yellow; distinctly contrasting dark brown mesosomal macrosetae (Grenada) . . . . . Nylanderia coveri

• Body ranging from dark brown to yellow, but if yellow then mesocoxae and metacoxae white and noticeably lighter than rest of body . . . . . 16

16

return to couplet #15

• Body color brown to yellow; coxae always lighter than mesosoma, becoming white if specimen is yellow . . . . . Nylanderia guatemalensis

• Body color brown to dark brown with meso/metacoxae contrasting bright white to yellow with rest of body . . . . . Nylanderia steinheili

17

return to couplet #14

• Body yellow, gaster sometimes brownish-yellow; pubescence on head, mesosoma, and gaster white but not contrasting with yellow cuticle; macrosetae brown across body contrasting with yellow cuticle typically across entire body (Dominican Republic) . . . . . Nylanderia esperanza

• Body dark brown to yellowish-brown; pubescence on head, mesosoma, and gaster white and contrasting with darker cuticle; macrosetae brown across body, sometimes contrasting on yellow legs and scapes only . . . . . 18

18

return to couplet #17

• SL<0.75 mm; WL <0.8mm; REL <25 (Cuba) . . . . . Nylanderia sierra

• SL >0.75mm; WL >0.8mm; REL >25 . . . . . 19

19

return to couplet #18

• Dark brown species with posterolateral portions of the head almost always lighter brown than the remainder of the head; HL > 0.72mm (0.64–0.75); HW> 0.6mm (0.55–0.7) (Dominican Republic) . . . . . Nylanderia bibadia

• Color variable, but if dark brown then head uniformly colored; typically HL <0.68mm (0.56–0.68); typically HW <0.6mm (0.48–0.59) . . . . . 20

20

return to couplet #19

• SMC typically greater than 30 (measured range: 26–38); head in full-face view distinctly ovate with rounded posterolateral corners (Cuba) . . . . . Nylanderia wardi

• SMC typically less than 25 (measured range: 18–25); head in full-face view distinctly quadrate with angled posterolateral corners (Dominican Republic) ......................................................... Nylanderia metacista

++ Workers of N. fulva and N. pubens cannot be reliably separated. In order to morphologically identify these two species, male specimens are required - return to couplet #5.