Temnothorax mongolicus

Temnothorax mongolicus (Pisarski, 1969) Fig. 1 Leptothorax serviculus subsp. mongolicus Pisarski, 1969: 299, figs 5–10 (w.) MONGOLIA. Palearctic. Paratype worker images (Antweb 2023, CASENT 0916693) examined. Leptothorax opaciabdomin Chang & He, 2001: 2, figs 2, 6, 10 (w.) CHINA. Palearctic. Syn. nov. Leptothorax mongolicus – Radchenko 1994: 156. Temnothorax mongolicus – Bolton 2003: 271. Temnothorax opaciabdomin – Zhou et al. 2010: 10 (in key). Holotype worker (Fig. 2a–c) examined. Diagnosis In full-face view, the shapes of the head capsule, mandibles, clypeus and antennae of the holotype worker of Leotothorax opaciabdomin (Fig. 2A) are similar to the ones of the paratype worker of T. mongolicus (Fig. 1A). Head roughly rectangular, longer than broad, posterior margin nearly straight, posterior corners broadly rounded, lateral margins weakly convex. Clypeus with median carina, anterior margin weakly convex. Antennae 12-segmented, scapes failing to reach posterior head margin. In lateral view, the holotype worker of Temnothorax opaciabdomin (Fig. 2B) also has similar to shaped mesosoma and petiole the paratype worker of T. mongolicus (Fig. 1B). Promesonotum moderately convex. Metanotal groove absent. Propodeal dorsum gently sloping down posteriorly; propodeal spines shorter than declivity. Petiole without anterior peduncle; petiolar node with straight anterior and posterior margins. In dorsal view, the holotype worker of Temnothorax opaciabdomin (Fig. 2C) shows similar to shape in mesosoma and petiole the paratype worker of T. mongolicus (Fig. 1C). Pronotum broad, humeral corners broadly rounded, lateral margins strongly convex. Mesothorax moderately constricted and narrowing posteriorly, lateral margins moderately concave. Propodeum roughly rectangular, lateral margins almost straight; spines short, pointed posterolaterally. Petiole widening posteriorly and slightly longer than broad, lateral margins weakly convex. Postpetiole roughly trapezoidal. The holotype worker of Temnothorax opaciabdomin (Fig. 2) shows similar to characters in body surface sculpture, pilosity and color to paratype worker of T. mongolicus (Fig. 1). Head dorsum longitudinally rugose with interface finely reticulate, gradually reticulate posteriorly and laterally. Promesonotum, propodeum, petiole and postpetiole finely reticulate with interface punctate. Gaster smooth and shiny. Head and gaster blackish brown, thorax, petiole and postpetiole light brown. Taxonomic notes After the above comparison, we could not find significant differences between the two species. Although in the original description, Chang & He (2001) stated “Gaster finely punctate and therefore not very shiny”. In the key, they stated “Gaster relatively coarsely punctate and therefore not very shiny”, and the Latin name “opaciabdomin ” means the gaster is opaque. Zhou et al. (2010) adopted the original description and stated in the key “First gastral tergite coarsely punctuate, opaque”. However, after reexamining the images of holotype specimen, we found the gaster of T. opaciabdomin is wholly smooth and shiny. Therefore, we are confident that T. opaciabdomin is a junior synonym of T. mongolicus.