Key to Messor instabilis group from Greece

Key to the species of the Messor instabilis group from Greece (modified from Salata et al., 2023).

Note: Proper identification is possible only for a series of major workers.

1

• Large species, mean HW in the largest workers > 2.6 mm => 2
• Smaller species, mean HW in the largest workers < 2.5 mm => 4

2

return to couplet #1

• Occipital corners with 1–4 (only occasionally 5 or 6) large setae. Postpetiole with narrowing attachment to the gaster, PPW/PW index in major workers < 1.3 (mean 1.21) => 3
• Occipital corners with 7–11 (occasionally 12 or 13) large setae. Postpetiole with broad attachment to the gaster, PPW/PW index in major workers > 1.3 (mean 1.39). Only Dodecanese => Messor kardamenae

3

return to couplet #2

• First gastral tergite with strong background microreticulation; pits around bases of setae in basal part of gaster form short and deep longitudinal striae. Mesosoma in large workers often bicoloured, red with black patches, in the largest workers often almost entirely black. Crete => Messor concolor

• First gastral tergite with moderate background microreticulation, often reduced; pits around bases of setae in basal part of gaster either do not form longitudinal striae or form only short and shallow striae. Mesosoma in large workers usually completely red or with small brown to black patches, never entirely black. Widespread in the Balkans but in Crete mostly in coastal areas or in tourist resorts => Messor wasmanni

4

return to couplet #1

• Mesosoma completely to predominantly red or predominantly brown to black with reddish discoloration on sides of mesonotum and dorsum of propodeum (Figs 1–9, 29–32), if mesosoma completely black then occipital part of head with 12–20 large setae => 5
• Mesosoma completely black, only occasionally anterolateral corners of pronotum with reddish discoloration (Figs 15–18). Occipital part of head always with less than 12 large setae. Cyclades: Serifos => Messor danaes

• 

  Salata et al. (2023), Figures 1, 2. Major worker of Messor atanassovii, population from Epirus. 1, dorsal 2 lateral. Scale bar: 1 mm.
• 

  Salata et al. (2023), Figures 3, 4. Minor worker of Messor atanassovii, population from Epirus. 3, dorsal. 4, lateral. Scale bar: 1 mm.
• 

  Salata et al. (2023), Figures 5, 6. The palest specimens of Messor atanassovii, population from Epirus. 5, medium worker. 6, minor worker. Scale bar: 1 mm.
• 

  Salata et al. (2023), Figures 7–9. Workers of Messor atanassovii, population from Thraki. 7, 8, medium workers. 9, major worker. Scale bar: 1 mm.
• 

  Salata et al. (2023), Figures 29, 30. Major worker of Messor veneris, holotype. 29, dorsal. 30, lateral. Scale bar: 1 mm.
• 

  Salata et al. (2023), Figures 31, 32. Minor worker of Messor veneris. 31, dorsal. 32, lateral. Scale bar: 1 mm.
• 

  Salata et al. (2023), Figures 15, 16. Major worker of Messor danaes, holotype. 15, dorsal. 16, lateral. Scale bar: 1 mm.
• 

  Salata et al. (2023), Figures 17, 18. Minor worker of Messor danaes. 17, dorsal. 18, lateral. Scale bar: 1 mm.

5

return to couplet #4

• Occipital area and vertex of head with 4–8 large setae (Figs 29, 31, 33) => 6
• Occipital area and vertex of head with 12–20 large setae (Figs 1, 3, 10) => Messor atanassovii

• 

  Salata et al. (2023), Figures 29, 30. Major worker of Messor veneris, holotype. 29, dorsal. 30, lateral. Scale bar: 1 mm.
• 

  Salata et al. (2023), Figures 31, 32. Minor worker of Messor veneris. 31, dorsal. 32, lateral. Scale bar: 1 mm.
• 

  Salata et al. (2023), Figures 33, 34. Head of Messor veneris. 33, major worker. 34, minor worker. Scale bar: 1 mm.
• 

  Salata et al. (2023), Figures 1, 2. Major worker of Messor atanassovii, population from Epirus. 1, dorsal 2 lateral. Scale bar: 1 mm.
• 

  Salata et al. (2023), Figures 3, 4. Minor worker of Messor atanassovii, population from Epirus. 3, dorsal. 4, lateral. Scale bar: 1 mm.
• 

  Salata et al. (2023), Figures 10, 11. Head of Messor atanassovii, population from Epirus. 10, major worker. 11, minor worker. Scale bar: 1 mm.

6

return to couplet #5

• Pronotum with thin and dense sculpture, its dorsum with reduced sculpture and sometimes with smooth patches centrally; first gastral tergite never with erect setae (Figs 21, 23). Milos Island of Cyclades => Messor veneris

• Propodeum with thick and sparser sculpture, its dorsum never with reduced sculpture or smooth patches; gaster with sparse and erect setae. Endemic to Crete => Messor creticus

• 

  Salata et al. (2023), Figures 21, 22. Major worker of Messor kardamenae, holotype from Kos. 21, dorsal. 22, lateral. Scale bar: 1 mm.
• 

  Salata et al. (2023), Figures 23, 24. Minor worker of Messor kardamenae, population from Kos. 23, dorsal. 24, lateral. Scale bar: 1 mm.

References

• Salata, S., Lapeva-Gjonova, A., Georgiadis, C., Borowiec, L. 2023. Review of the Messor semirufus complex (Hymenoptera, Formicidae) in Greece. ZooKeys 1185, 105–142 (doi:10.3897/zookeys.1185.111484).