Key to Tetramorium meridionale species-group

Key to the members of the Tetramorium meridionale species-group based on worker caste, based on Salata et al. (2024).

1

Body brown to yellow; occipital surface of the head with transverse rugae; sides posterolateral from eyes often with reduced sculpture (Figures 4C, 5C, 6C) => Tetramorium meridionale
Body orange; occipital surface with rugae distinctly arching posterolaterally, transverse rugae absent; sides posterolateral from eyes never with reduced sculpture (Figures 1A, 1B, 2A, 2B, 4B, 5B, 6B) => 2

Salata et al. (2024), Figure 4. Worker dorsal, syntype; A. Tetramorium biskrense (Zach Lieberman, from www.antweb.org), B. T. davidi (Zach Lieberman, from www.antweb.org), C. T. meridionale (Will Ericson, from www.antweb.org).
Salata et al. (2024), Figure 5. Worker lateral, syntype; A. Tetramorium biskrense (Zach Lieberman, from www.antweb.org), B. T. davidi (Zach Lieberman, from www.antweb.org), C. T. meridionale (Will Ericson, from www.antweb.org).
Salata et al. (2024), Figure 6. Worker head, syntype; A. Tetramorium biskrense (Zach Lieberman, from www.antweb.org), B. T. davidi (Zach Lieberman, from www.antweb.org), C. T. meridionale (Will Ericson, from www.antweb.org).
Salata et al. (2024), Figure 1. Tetramorium flavocostatum, holotype worker; A. dorsal, B. lateral. Scale bar 0.5 mm.
Salata et al. (2024), Figure 2. Tetramorium flavocostatum, head; A. worker, B. head of worker in oblique view for illustration of sculpture in the occipital part of the head, C. gyne. Scale bar 0.5 mm.

Propodeal spines well developed; mesosoma with thin and dense sculpture, most often pronotal dorsum centrally with sculpture reduced or absent (Figures 4B, 5B, 6B) => Tetramorium davidi
Propodeal spines minute; whole mesosoma with thick and sparse longitudinal rugae with smooth interspaces (Figures 1A, 1B, 2A, 2B) => Tetramorium flavocostatum

Salata et al. (2024), Figure 4. Worker dorsal, syntype; A. Tetramorium biskrense (Zach Lieberman, from www.antweb.org), B. T. davidi (Zach Lieberman, from www.antweb.org), C. T. meridionale (Will Ericson, from www.antweb.org).
Salata et al. (2024), Figure 5. Worker lateral, syntype; A. Tetramorium biskrense (Zach Lieberman, from www.antweb.org), B. T. davidi (Zach Lieberman, from www.antweb.org), C. T. meridionale (Will Ericson, from www.antweb.org).
Salata et al. (2024), Figure 6. Worker head, syntype; A. Tetramorium biskrense (Zach Lieberman, from www.antweb.org), B. T. davidi (Zach Lieberman, from www.antweb.org), C. T. meridionale (Will Ericson, from www.antweb.org).
Salata et al. (2024), Figure 1. Tetramorium flavocostatum, holotype worker; A. dorsal, B. lateral. Scale bar 0.5 mm.
Salata et al. (2024), Figure 2. Tetramorium flavocostatum, head; A. worker, B. head of worker in oblique view for illustration of sculpture in the occipital part of the head, C. gyne. Scale bar 0.5 mm.