Messor muticus

Identification
Steiner et al. (2018) - Worker and queen. Colour similar to Messor ponticus, usually darker than Messor ibericus, Messor mcarthuri, and Messor structor. Discrimination from M. ibericus, M. mcarthuri, and M. ponticus by base of scape with rounded lobe, long 1st funicular segment, and by coarser sculpture of mesopleuron, from M. ponticus by abundant standing setae on side of head. Surface of 1st gastral tergite less imbricate, than in M. ibericus and M. mcarthuri, similarly to M. structor and M. ponticus.

Worker. Similarly sized as M. ibericus and M. structor, smaller than M. mcarthuri and M. ponticus. For individuals difficult to discriminate from M. ponticus or M. structor using qualitative morphology, morphometrics-based linear discriminant functions is available. M. structor and M. muticus are well separated longitudinally and ecologically.

Queen. Larger than M. ibericus, similarly sized as M. mcarthuri, M. ponticus, and M. structor. Discrimination from M. ibericus by reduced reticulation and rugosity of anepisternum and katepisternum.

Distribution based on Regional Taxon Lists
Palaearctic Region: Armenia, Kazakhstan, Kyrgyzstan, Romania, Russian Federation, Ukraine.

Biology
mtDNA: Ten haplotypes of COI (1375 bp) known; (GenBank).

Nomenclature

 *  muticus. Myrmica mutica Nylander, 1849: 39 (w.q.m.) RUSSIA.
 * Combination in Aphaenogaster: Roger, 1863b: 29.
 * Combination in Stenamma (Messor): Emery, 1898c: 126.
 * Combination in Messor: Ruzsky, 1903b: 315; Emery, 1908e: 456.
 * As unavailable (infrasubspecific) name: Emery, 1908e: 456; Forel, 1911d: 347; Emery, 1912f: 96; Emery, 1921f: 73; Santschi, 1921a: 110; Soudek, 1922: 35; Karavaiev, 1926b: 101; Santschi, 1926f: 291; Soudek, 1931: 8; Santschi, 1934d: 275.
 * Subspecies of structor: Emery, 1898c: 142; Ruzsky, 1903b: 315; Ruzsky, 1904b: 4; Emery, 1915h: 1; Bondroit, 1918: 151; Stärcke, 1926: 86 (in key); Santschi, 1934d: 275; Novák & Sadil, 1941: 82 (in key); Hamann & Klemm, 1976: 671.
 * Subspecies of rufitarsis: Arnol'di, 1977b: 1643 (in key).
 * Junior synonym of rufitarsis: Emery, 1921b: 211; Bernard, 1967: 144.
 * Junior synonym of structor: Mayr, 1855: 464; Nylander, 1856b: 85; Smith, F. 1858b: 162; Roger, 1863b: 29; Emery & Forel, 1879: 462; Atanassov & Dlussky, 1992: 114; Bolton, 1995b: 255; Radchenko, 2007: 31; Legakis, 2011: 11.
 * Status as species: Agosti & Collingwood, 1987b: 271 (in key); Borowiec, L. & Salata, 2012: 514; Borowiec, L. 2014: 110 (error); Steiner et al., 2018: 400.

Description
Steiner et al. (2018) - Worker and queen. Colour: Head and mesosoma brown to brownish red, gaster dark brown. Major workers can be dark brown entirely. Size: Medium sized. Head: Mostly entirely costate. In major and frequently in medium worker, costae on much of postocular region. However, in minor and sometimes in medium worker, costae mostly reduced in postocular region; head almost smooth, with fine costulae and microreticulate, frequently shining. Erect setae abundant on side of head from occiput to mandibular insertion. Scape: Base with rounded, laterally-downward directed lobe; very distinct in minor worker; can be reduced in major worker. 1st funicular segment long and flattened, almost as long as 2nd and 3rd segment together. Clypeus: Median notch well defined; can be shallow in minor worker. Pronotum: Middle mostly coarsely and irregularly costate throughout. Mesonotum: Coarsely and irregularly costate throughout. Mesopleuron: Coarsely sculptured with irregular transverse costae; shallow punctuation among costae. Minor workers less costate with almost no punctuation. Propodeum: Mostly smoothly rounded; in major worker, often obliquely rounded, rarely angled. Surface of 1st gaster tergite: Basis imbricate, middle sometimes with isolated snow-flakes-like structure. Covered with yellowish, thin, sparse hairs, some of which decumbent and subdecumbent in some individuals.

Queen: Metanotum: Coarsely and irregularly costate. Anepisternum and katepisternum: Sides covered with fine costulae, middle smooth and shining.

Male: Anepisternum and katepisternum: At least sides covered with fine costulae, sometimes middle smooth and shining.

Type Material
Steiner et al. (2018) - 1q, Ross. mer., Mus. Zool. H:fors, spec. typ. No. 5894, Myrmica mutica Nyl., T, Ross. mer. Motsch., coll. Nyland. 1 m, Ross. mer., Mus. Zool. H:fors, spec. typ. No. 5895, Myrmica mutica Nyl., T, Ross. mer. Motsch., coll. Nyland. 1w, Ross. mer., Mus. Zool. H:fors, spec. typ. No. 5896, Myrmica mutica Nyl., T, Ross. mer. Motsch., coll. Nyland.

References based on Global Ant Biodiversity Informatics

 * Agosti, D. and C.A. Collingwood. 1987. A provisional list of the Balkan ants (Hym. Formicidae) and a key to the worker caste. I. Synonymic list. Mitteilungen der Schweizerischen Entomologischen Gesellschaft, 60: 51-62
 * Borowiec L. 2014. Catalogue of ants of Europe, the Mediterranean Basin and adjacent regions (Hymenoptera: Formicidae). Genus (Wroclaw) 25(1-2): 1-340.
 * Borowiec L., and S. Salata. 2012. Ants of Greece - Checklist, comments and new faunistic data (Hymenoptera: Formicidae). Genus 23(4): 461-563.
 * Collingwood, C. A. 1993. A Comparitive Study of the Ant Fauna of Five Greek Islands. Biologia Gallo-hellenica. 20,1:191-197
 * Collingwood, C. A.. "A comparative study of the ant fauna of five Greek islands." Biologia Gallo-Hellenica 20 (1993): 191-197.
 * Emery, C.. "Escursioni zoologiche del Dr. Enrico Festa nell'Isola di Rodi. XII. Formiche." Bollettino del Museo di Zoologia ed Anatomia Comparatadella Reale Università di Torino 30 (1915): 1-7.
 * Forel A. 1911. Fourmis nouvelles ou intéressantes. Bull. Soc. Vaudoise Sci. Nat. 47: 331-400.
 * Hamann H. H. F., and W. Klemm. 1976. Ergebnisse der von Dr. O. Paget und Dr. E. Kritscher auf Rhodos durchgeführten zoologischen Exkursionen. XVI. Formicidae. Annalen des Naturhistorischen Museums in Wien 80: 669-679.
 * Kratochvíl J., V. Novák, and J. Snoflák. 1944. Mohelno. Soubor práci venoványch studiu vyznamne památky prírodní. 5. Hymenoptera - Aculeata. Formicidae - Apidae - Vespidae. Arch. Svazu Ochr. Prír. Domov. Moravé 6: 1-155.
 * Petrov I. Z., and C. A. Collingwood. 1992. Survey of the myrmecofauna (Formicidae, Hymenoptera) of Yugoslavia. Archives of Biological Sciences (Belgrade) 44: 79-91.
 * Salata S., L. Borowiec, and A.Trichas. 2018. Taxonomic Revision of the Cretan Fauna of the Genus Temnothorax Mayr, 1861 (Hymenoptera: Formicidae), with Notes on the Endemism of Ant Fauna of Crete. Annales Zoologici (Warsaw) 68(4): 769-808.
 * Santschi, F.. "Fourmis d'une croisière." Bulletin et Annales de la Société Entomologique de Belgique (Bruxelles) 74 (1934): 273-282.
 * Steiner F. M., S. Csosz, B. Marko, A. Gamisch, L. Rinnhofer, C. Folterbauer, S. Hammerle, C. Stauffer, W. Arthofer, B. C. Schlick‐Steiner. 2018. Turning one into five: Integrative taxonomy uncovers complex evolution of cryptic species in the harvester ant Messor “structor”. Molecular Phylogenetics and Evolution https://doi.org/10.1016/j.ympev.2018.04.005