Tetramorium hungaricum

This species has been found in arid meadows, dry grasslands, stony shrublands, gravel pits and oak forest.

Identification
A member of the Tetramorium caespitum complex. The species can be determined with a discriminant analysis of a set of morphological measurements. See Wagner et al. (2017) and https://webapp.uibk.ac.at/ecology/tetramorium/

Distribution
Pannonian zone, Balkans, Eastern Europe.

Distribution based on Regional Taxon Lists
Palaearctic Region: Austria, Bulgaria, Czech Republic, Greece, Hungary, Romania, Russian Federation, Slovenia.

Biology
Wagner et al. (2017) - More thermophilic than all other species except Tetramorium breviscapus, Tetramorium fusciclava, and Tetramorium immigrans; TAS of 43 sites 20.6 ± 2.7 °C [16.2, 26.2]. Typical habitats are arid meadows, dry grasslands, stony shrubland, gravel pits; also oak forests.

Adult sexuals in nests on 20 June ± 6 [8 June, 24 June] (n = 7).

Nomenclature

 *  hungaricum. Tetramorium caespitum subsp. hungarica Röszler, 1935: 78, figs. (w.q.) HUNGARY. Subspecies of semilaeve: Novak & Sadil, 1941: 86. Raised to species: Röszler, 1951: 88. Material of the unavailable names biroi, haltrichi, rufitarsis, szaboi referred to hungaricum by Csösz & Markó, 2004: 52.

Worker
Wagner et al. (2017) - Smallest species of complex, CS = 657 ± 34 [584, 722] μm. Dark brown to blackish.

Head moderately elongate, CL / CW = 1.020 ± 0.014 [0.996, 1.051]. Eye large, EYE / CS = 0.184 ± 0.007 [0.170, 0.194]. Scape short, SLd / CS = 0.747 ± 0.015 [0.716, 0.773]. Mesosoma shortest within complex and narrow, ML CS = 1.103 ± 0.018 [1.064, 1.146], MW / CS = 0.628 ± 0.008 [0.608, 0.645].

Promesonotal dorsum convex, metanotal groove shallow. – Smoothest and shiniest surface within complex: longitudinal costae and costulae on head dorsum and occiput usually interrupted by large-scale smooth and shiny areas. Postoculo-temporal area of head with few longitudinal costae and costulae, POTCos = 2.14 ± 1.21 [0.13, 4.50]. Longitudinal costae and costulae on mesosoma interrupted by smooth and shiny areas, lateral side of propodeum with strongly pronounced smooth and shiny area, Ppss = 85.6 ± 36.1 [21.1, 169.5] μm. Dorsum of petiolar node usually smooth, exceptionally feebly microreticulated. – Connected stickman-like or reticulate microsculpture: small units scattered over 1st gastral tergite, MC1TG = 14.91 ± 2.53 [9.64, 20.85]. – Some workers with long c-shaped, crinkly, or sinuous hairs on ventral head posterior to buccal cavity.

Male
Paramere structure belongs to caespitum-like form: ventral paramere lobe with one or two sharp corners; without distinct emargination between paramere lobes in posterior view, both paramere lobes reduced in size; in ventro-posterior view, second corner on ventral paramere lobe missing or < 87 μm apart from first. In posterior view, typically only one sharp corner on ventral lobe.

Type Material
Wagner et al. (2017) - Lectotype designation: Csosz & Marko 2004: 53. Type material not investigated. Nagytétény (Hungary), 47.391° N, 18.987° E, 101 m a.s.l., leg. P. Röszler, 24.VII.1934.