Tetramorium aegeum Radchenko, 1992

Csősz, Sándor & Schulz, Andreas, 2010, A taxonomic review of the Palaearctic Tetramorium ferox species-complex (Hymenoptera, Formicidae), Zootaxa 2401, pp. 1-29 : 12-15

Tetramorium aegeum Radchenko, 1992

Tetramorium caespitum subsp. ferox var. levigata Karavaiev, 1926: 167 . Unavailable name.

Tetramorium inerme subsp. laevigatum Arnol'di, 1948: 211. First available use of Tetramorium caespitum subsp. ferox var. levigata Karavaiev, 1926 ; junior primary homonym of T. laevigatum Mayr, 1901 . Syntype worker, gyne, male (3w, 2q, 2m): Azerbaijan, valley of Pir-sagat, 18.V.1907 (Kaznakow and Schelkownikow) [label: 5865. Coll., Karawaiwi; Syntypus Tetramorium , caespitum ferox v., levigata Karaw. For label data see note] (examined) [SIZK].

Tetramorium caespitum ferox var. aequa Baroni Urbani, 1971: 361 . Unavailable name, proposed replacement name for T. caespitum subsp. ferox var. levigata Karavaiev, 1926 .

Tetramorium levigatus: Radchenko & Arakelian, 1990: 376 .

Tetramorium aegea Radchenko, 1992b: 55 . First available replacement name for Tetramorium inerme subsp. laevigatum Arnol'di 1948.

Description of workers (figs 17–19, 21). Small size, CS 683 [648, 710]. Whole body and appendages yellow. Head slightly longer than broad, CL/CW 1.04 [1.03, 1.06], with feebly convex sides, straight posterior margin of the head with widely rounded corners. Eyes large, EYE 0.18 [-]. Frons wide, FR/CS 0.40 [0.40, 0.41], frontal lobes as wide as the frons, FL/FR 1.00 [-]. Scape short, SL/CS 0.75 [-], without dorso-basal carina, surface smooth and shiny. Promesonotal dorsum slightly convex, metanotal groove shallow. Propodeal denticles very short. Dorsal surface of petiole rounded, petiolar node higher than long, seen in profile NOH/ NOL 1.09 [1.04, 1.12].

Head dorsum, posterior head surface, mesosoma dorsum, petiolar node and postpetiole smooth and shiny, ground surface smooth and shiny, or finely microreticulate. First gastral tergite imbricate. Ventral surface of head with a row of short setae and long C-shape hairs arising just posteriorly to buccal cavity forming a psammophore.

Description of gynes (figs 14–16, 20). Small size, CS 864 [858, 870]. Head distinctly broader than long, CL/CW 0.90 [0.89, 0.91], with straight, sub-parallel sides, straight posterior margin with rounded corners. Frons wide, FR/CS 0.44 [-]. Scape short, SL/CS 0.70 [0.70, 0.71]. Head as wide as scutum, MW/CS 0.98 [0.97, 0.99]. Propodeal denticles short. Petiole and postpetiole wide, CS/PEW 1.62 [1.55, 1.68], CS/PPW 1.35 [-].

Whole body and appendages yellow. General appearance of head and mesosoma very feebly sculptured, surface smooth, appears shiny. Frons and genae with very fine longitudinal rugulae, or completely smooth, rest of head smooth. Scutum, scutellum, and anepisternum smooth and shiny, ventral part of katepisternum always smooth and shiny. Petiolar node and postpetiole feebly microreticulate, or smooth and shiny. First gastral tergite imbricate. Ventral surface of head with a row of short setae and long C-shape hairs arising just posteriorly to buccal cavity forming a psammophore.

Description of males. Head sides feebly convex, posterior margin widely rounded. Scutum broader than head. Propodeal denticles reduced, propodeum rounded in profile. Dorsum of petiolar node without a continuous transverse crest, dorsolaterally sharp and angulate. Whole body and appendages light brown. Head finely rugulo-reticulate, between main sulpturation microreticulate. Scutum, scutellum, anepi- and katepisternum finely rugulose, and smooth in part. Petiole and postpetiole finely rugulo-reticulate, between main sculpturation microreticulate.

Diagnosis. Workers and gynes of T. aegeum can be confused with those of T. diomedeum . Both species are less sculptured than relatives in the complex. The head and mesosoma are frequently smooth and shiny, but the imbricate first gastral tergite of T. aegeum is unique within this group. We had only a few samples of T. aegeum , so intraspecific variation is poorly known.

Discriminant function D(4a) = 0.0744 FR +0.0762 PEW -0.0616 PPW -0.1097 POC +8.0688 for T. diomedeum and T. aegeum workers resulted in 100% success, and each case (226 individuals) was correctly identified. The mean D(4a) scores for T. diomedeum workers (n=223) was -2.457 ±0.99 [-5.379, +0.294], for nest means (n=42) -2.462 ±0.72 [-4.047, -1.266]. The mean scores for T. aegeum workers (n=3) was 2.457 0.21 [+2.290, +2], for nest mean (n=1) +2.457642.

For the cumulative discriminant analysis for workers see Tables 3 & 4 and gynes see Tables 5 & 6 . Morphometric characters and indices for workers and gynes are provided in Table 7 & 8.

FIGURES 14–21. Tetramorium aegeum Radchenko, 1992 . Gyne mesosoma, petiole and postpetiole, dorsal view (Fig. 14), lateral view (Fig. 15); gyne head, dorsal view (Fig. 16); worker head, dorsal view (Fig. 17); worker mesosoma, petiole and postpetiole, dorsal view (Fig. 18), lateral view (Fig. 19); imbricate microsculpture on the 1st gastral tergite of gyne (Fig. 20); the most densely sculptured antero-lateral part on the 1st gastral tergite of worker (Fig. 21).

Note. In the original description ( Karawajew, 1926: 169) the following designation was given for the type material: “Tal des Pir-sagat (Gouv. Baku) 18.V.1907., Kaznakow und Schelkownikow (w, q, m)” without indication of the series number. The syntype material examined by us had no indication for the locality. This makes the status of our syntype material doubtful, but the lack of other available material and the fact that this series is deposited in the original Karawajew collection led us to treat the above series as syntype material.

Material examined. Azerbaijan. Only the type material is known.