Tetramorium caespitum species group

This is a Palaearctic species group with a number of species complexes.

Tetramorium ferox species complex
Based on Csösz and Schulz 2011.

Species

 * Tetramorium aegeum
 * Tetramorium densopilosum
 * Tetramorium diomedeum
 * Tetramorium ferox
 * Tetramorium feroxoides

Identification
Key to Tetramorium ferox species complex workers

Diagnosis
Species belonging to the T. ferox-complex within the caespitum-group can be defined by the combination of the following characters.

Workers
 * petiole and postpetiole relatively broad (CS/PEW > 2.31, CS/PPW > 1.93), in T. aegeum and T. diomedeum very broad.
 * head, mesosoma and waist moderately sculptured; dorsum of both petiolar node and postpetiole medially shiny.
 * first gastral tergite smooth (excluding T. aegeum, for which 1st gastral tergite is imbricate); several long, erect hairs always appear on first gastral tergite.
 * propodeum in profile flat, sloping down at an angle of approximately 45°.
 * propodeal teeth small, developed as triangular denticles, in contrast to a prominent propodeal lobe.

Queens
 * mandibles smooth and shiny.
 * petiole and postpetiole wide.
 * mesosoma low, with flattened dorsum (seen in profile); scutum (seen from above) somewhat narrowed anteriorly and does not completely cover the pronotum, so that humeri (i. e. anterolateral pronotal angles) are easily visible.
 * head, mesosoma and waist moderately sculptured or smooth.
 * petiole and postpetiole with some very long thin hairs, in contrast to the first gastral tergite which is generally without long erect hairs.

Males
 * head and mesosoma moderately sculptured.
 * sides of petiole and postpetiole angulate in dorsal view.
 * stipes of genitalia curved inwards at the tip, and with flattened apical plate (seen in caudal view)

Tetramorium chefketi species complex
Based on Csösz & Schulz 2007.

Species

 * Tetramorium alternans
 * Tetramorium anatolicum
 * Tetramorium annectens
 * Tetramorium chefketi
 * Tetramorium exile
 * Tetramorium forte
 * Tetramorium moravicum
 * Tetramorium rhodium
 * Tetramorium sanetrai
 * Tetramorium sulcinode
 * Tetramorium syriacum

Diagnosis
Workers

a) polygonal striae are continuous on 1st gastral tergite, and is sometimes microreticulate basally. Polygonal striation: interstices marked by feeble anastomosing striae (Fig. 8.), compare to microreticulation: interstices marked by very feeble elevated structures, like rugulae (Fig. 6, 7.);

b) head, alitrunk and waist coarsely sculptured, dorsum of petiolar node and postpetiole coarsely rugose and/or reticulate.

c) petiole and postpetiole relatively narrow (CS/PEW and CS/PPW, Table 1);

d) ground surface on the frons is usually coarsely microreticulate;

Gynes

e) alitrunk is low, dorsum is flattened in profile;

f) scutum in dorsal view is somewhat narrowed anteriorly and does not cover completely the pronotum, humeri are well visible;

g) head, alitrunk and waist are coarsely sculptured, and petiole and postpetiole dorsum coarsely rugose or/and reticulate;

h) polygonal striae disrupted on 1st first gastral tergite, sometimes microreticulate basally;

i) mandibles are longitudinally striate;

j) petiole and postpetiole are relatively narrow (WAIST, Table 2);

Males

k) head and alitrunk with usually coarsely sculpture, ground surface microreticulate;

l) sides of petiole and postpetiole not angulate as in the ferox species complex (in dorsal view);

m) first gastral tergite usually smooth and shiny, or feebly striate;

n) stipes of genitalia blunt, curved inwards at the top, with flattened apical plate (in caudal view)