Key to Formica rufibarbis group

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This worker key is based on: Seifert, B. and R. Schultz. 2009b. A taxonomic revision of the Formica rufibarbis Fabricius, 1793 group (Hymenoptera: Formicidae). Myrmecologische Nachrichten. 12:255-272. PDF

The complex Numobat procedures presented in this paper are indispensable for safe and testable species delimitations but we are aware that these are not easily reproducible by the majority of practitioners doing ecological and faunistic research. As a consequence, we present here a simplified dichotomous key which should enable determinations in the majority of cases. We have tried to find a less time-consuming determination method by strongly reducing the number of required characters and using primary (uncorrected) data. The entry values in the key are arithmetic means of usually three workers per nest. The error estimations given in the discriminant functions refer to this sample size and our accuracy of data recording. To reduce working time when using discriminant functions, we recommend beginning with one worker per sample and only extending the sample size when the resulting discriminant value is close to zero.

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Seifert and Schultz 2009. Figures 3 - 7: lateral aspect of (3) the neotype of F. rufibarbis, (4) the neotype of F. cunicularia, (5) F. clara, (6) the holotype of F. orangea, and (7) the holotype of F. tarimica Setae numbers in F. clara show the average situation.
Seifert and Schultz 2009. Figs. 8 - 11: Lateral aspect of (8) the holotype of F. anatolica sp.n., (9) the holotype of F. tianshanica sp.n., (10) the holotype of F. persica sp.n., and (11) F. glabridorsis. Setae numbers in F. glabridorsis show the average situation.

1

  • Unilateral number of standing setae on underside of head 0.7 - 2.8. Petiole scale wide, PEW / CS 0.483 ± 0.017. Eye large, EYE / CS 0.303 ± 0.010. Head short, CL / CW 1.110 ± 0.018. 40 - 90% of mesosomal surface dark brown. Dorsal mesosoma always with setae. Asia Minor (Taurus Mountains) only (Fig. 8) . . . . . Formica anatolica
Formica anatolica antweb1008386 h 1 high.jpg
Formica anatolica antweb1008386 p 2 high.jpg
  • Unilateral number of standing setae on underside of head 0 - 0.7. Character combination of petiole width, eye size and head shape different. . . . . . 2

2

return to couplet #1

  • Distance between transverse microripples on dorsum of 1st gaster tergite very large: RipD 7.9 ± 0.5 μm. Pronotum hairy: nPN 9.2 ± 2.2. Head and scape elongated: CL / CW 1.174 ± 0.018, SL / CS 1.089 ± 0.021. Petiole scale narrow: PEW / CS 0.382 ± 0.018. Head and mesosoma usually reddish yellow. So far only known from the Tarim Basin (Fig. 7) . . . . . Formica tarimica
Formica tarimica antweb1008423 h 1 high.jpg
Formica tarimica antweb1008423 p 1 high.jpg
  • Distance between transverse microripples on dorsum of 1st gaster tergite smaller – if occasionally approaching 7.9 μm (in F. orangea sp.n.), then CL / CW and SL / CS clearly smaller. . . . . . 3

3

return to couplet #2

  • 87 - 100% of mesosomal surface orange and distance of transverse microripples on dorsum of 1st gaster tergite large: RipD 6.7 ± 0.5 μm. Head and scape rather short: CL / CW, 1.115 ± 0.017, SL / CS 1.027 ± 0.026. Dry steppes and semideserts from 58° to 104° E (Fig. 6) . . . . . Formica orangea
Formica orangea antweb1008418 h 1 high.jpg
Formica orangea antweb1008418 p 1 high.jpg
  • Character combination different. If mesosomal surface with more than 85% light reddish pigmentation, then RipD < 5.5 μm. . . . . . 4

4

return to couplet #3

  • Whole body with numerous standing setae: nPN 10.9 ± 2.9, nMN 6.6 ± 2.8, nPE 3.8 ± 1.1, nHFFL 3.4 ± 1.4 (Fig. 3). Discriminant 0.187 * nPN + 0.041 * nMN + 0.769 * nPE + 0.726 * nHFFL + 0.007 * nPRME - 4.644 * CL + 2.838 > 0 [CL in mm, error rate 0.5%] . . . . . Formica rufibarbis
Formica rufibarbis casent0173870 head 1.jpg
Formica rufibarbis casent0173870 profile 1.jpg
  • Whole body with fewer standing setae: nPN 1.7 ± 1.8, nMN 0.7 ± 1.0, nPE 0.4 ± 0.5, nHFFL 0.5 ± 0.5. Discriminant 0.187 * nPN + 0.041 * nMN + 0.769 * nPE + 0.726 * nHFFL + 0.007 * nPRME - 4.644 * CL + 2.838 < 0 [CL in mm, error rate 0.5%]. . . . . . 5

5

return to couplet #4

  • Distance between transverse microripples on dorsum of 1st gaster tergite large: RipD 6.0 ± 0.4 μm. . . . . . 6
  • Distance between transverse microripples on dorsum of first gaster tergite smaller. . . . . . 7

6

return to couplet #5

  • Scape long: SL > -1.248 * CW2 + 3.774 * CW - 1.27 [all measurements in mm]. Dorsal crest of petiole scale often obtuse-angled. North Iran (Fig. 10) . . . . . Formica persica
Formica persica antweb1008068 h 1 high.jpg
Formica persica antweb1008068 p 1 high.jpg
  • Scape shorter: SL < -1.248 * CW2 + 3.774 * CW - 1.27. Central Asian mountains from 71° to 109° E and 33° to 47° N (Fig. 9) . . . . . Formica tianshanica
Formica tianshanica antweb1008424 h 1 high.jpg
Formica tianshanica antweb1008424 p 1 high.jpg

7

return to couplet #5

  • Scape extremely long: 0.01986 * CW + 1.4442. E China from 99° to 116° E and 27° to 40° N (Fig. 11) . . . . . Formica glabridorsis
  • Scape shorter: SL / CW < -0.01986 * CW + 1.4442. . . . . . 8

8

return to couplet #7

  • Whole body often darker pigmented with stronger pigmentation contrast on genae (Fig. 1); discriminant with error rate 3.4%: 0.066 * PIGM + 2.014 * CONT + 1.641 * SL - 5.891 > 0. Discriminant with error rate 0.4%: 54.173 * EYE - 7.026 * CW - 3.675 * SL + 896 * RipD + 0.065 * PIGM + 1.624 * CONT - 15.0054 > 0. Usually in moderately xerothermic habitats with more developed herb layer (Fig. 4). Missing from Pakistan and India . . . . . Formica cunicularia
Formica cunicularia casent0173175 head 1.jpg
Formica cunicularia casent0173175 profile 1.jpg
  • Whole body usually light reddish brown with weak or missing pigmentation contrast on genae (Fig. 2); discriminant with error rate 3.4%: 0.066 * PIGM + 2.014 * CONT + 1.641 * SL -5.891 < 0. Discriminant with error rate 0.4%: 54.173 * EYE - 7.026 * CW - 3.675 * SL + 896 * RipD + 0.065 * PIGM + 1.624 * CONT - 15.0054 < 0. Usually in more xerothermic habitats with weakly developed herb layer (Fig. 5). Also in Pakistan and India . . . . . Formica clara
Formica lusatica casent0173858 head 1.jpg
Formica lusatica casent0173858 profile 1.jpg