Stenamma striatulum

Identification
Rigato (2011) - This is the smallest (especially the gyne) West European Stenamma, characterised, in both the female castes and the male, by finer and more longitudinally arranged rugulation on head (especially on frons and vertex) and promesonotum; the integument in females looks also somewhat shinier than in other species. Furthermore, the worker has moderately long propodeal spines (PSI nearly always > 1.6 and sometimes even > 2.00), and both female castes have scapes almost reaching the posterior margin of the head when laid back. The waist appears somewhat stocky and with petiolar sternite straight and postpetiolar sternite shorter than usual. Males have relatively weakly developed mandibles and a peculiar propodeal dorsum sculpturation: strongly finely reticulate-punctate with several transverse rugulae.

A quite distinctive species because of its small size, more regular longitudinal sculpturation, propodeal spines length and waist structure. The workers may be superficially confused with small specimens of Stenamma debile.

After the examination of dozens of S. striatulum workers, I discovered that in profile the short, shallow, somewhat rectangular prominence of the postpetiolar sternite in S. striatulum is about 40% of PPH; whereas the same structure in other species is > 50% of PPH. This feature seems consistent and allows the recognition of S. striatulum female castes at a glance.

Males of S. striatulum are easily recognizable by their combination of strongly sculptured propodeal dorsum and slightly reduced 4-  to 5-toothed mandibles, and by their low SI (< 45) and TI (< 135).

Distribution
Widespread and locally common in South Europe from Spain to Greece, and also occurring in Anatolia.

Distribution based on Regional Taxon Lists
Palaearctic Region: Andorra, Bulgaria, Croatia, Greece, Iberian Peninsula, Italy, Malta, Republic of Macedonia, Russian Federation, Slovenia, Spain, Switzerland, Turkey.

Nomenclature

 * . Stenamma westwoodi var. striatulum Emery, 1895c: 300 (footnote) (w.q.) ITALY.
 * Type-material: 2 syntype workers, 3 syntype queens.
 * Type-localities: 2 workers, 1 queen Italy: Capodimonte (Naples), 30.iii.1872 (C. Emery), 1 queen Italy: Piedmont (Gribodo), 1 queen Italy: Rome (no collector’s name).
 * Type-depository: MSNG.
 * Kutter, 1971: 259 (m.).
 * Subspecies of westwoodii: Emery, 1908c: 307; Emery, 1916b: 127; Emery, 1921f: 54; Müller, 1923a: 67; Grandi, 1935: 99.
 * Status as species: Müller, 1923b: 46; Kutter, 1963: 130; Kutter, 1971: 263; Baroni Urbani, 1971c: 39; Arnol'di, 1975: 1822; Kutter, 1977c: 74; Arnol’di & Dlussky, 1978: 535 (in key); Espadaler & Riasol, 1983: 227; Agosti & Collingwood, 1987a: 53; Agosti & Collingwood, 1987b: 269 (in key); Mei, 1992a: 416; Bolton, 1995b: 394; Poldi, et al. 1995: 3; Espadaler, 1997b: 31; DuBois, 1998b: 259 (redescription); Bračko, 2006: 140; Petrov, 2006: 89 (in key); Bračko, 2007: 18; Casevitz-Weulersse & Galkowski, 2009: 493; Liu, X. & Xu, 2011: 739 (in key); Rigato, 2011: 13 (redescription); Borowiec, L. & Salata, 2012: 535; Bharti, Gul & Sharma, 2012a: 328 (in key); Kiran & Karaman, 2012: 24; Borowiec, L. 2014: 161; Lebas, et al. 2016: 336; Salata & Borowiec, 2018c: 48; Seifert, 2018: 226.
 * Senior synonym of tscherkessicum: Arnol'di, 1975: 1822; Bolton, 1995b: 394; DuBois, 1998b: 259; Rigato, 2011: 13.
 * Distribution: Andorra, Bulgaria, Croatia, Greece, Italy (+ Sardinia), Malta, Russia, Serbia, Slovenia, Spain, Switzerland, Turkey.
 * tscherkessicum. Stenamma westwoodi var. tscherkessicum Arnol'di, 1928b: 214 (in text) (q.) RUSSIA.
 * Type-material: holotype queen.
 * Type-locality: Russia: NE coast of Back Sea, Abrau, nr Novorossiysk, 28.viii.1924 (Arnol’di).
 * Type-depository: ZMUM.
 * Junior synonym of striatulum: Arnol'di, 1975: 1822; Bolton, 1995b: 394; DuBois, 1998b: 259; Rigato, 2011: 13.

Worker
Rigato (2011) - TL 2.9–3.4; HL 0.67–0.78; HW 0.57–0.67; CI 83–89; SL 0.53–0.62; SI 89–97; PCI 26–34; PnW 0.38–0.46; AL 0.77–0.97; PSI 1.59–2.00; PeL 0.28–0.35; PPL 0.18–0.21; PeH 0.18–0.22; PPH 0.18–0.23; PeW 0.14–0.17; PPW 0.19–0.23; PI1 57–67; PI2 46–55; MTL 0.43–0.52; TI 73–81 (24 measured).

Queen
Rigato (2011) - TL 3.5–3.8; HL 0.75–0.80; HW 0.65–0.71; CI 85–90; SL 0.59–0.62; SI 86–91; PCI 24–32; AL 1.02–1.11; PSI 1.61–2.08; ScW 0.52–0.56; MnL 0.70–0.79; PeL 0.32–0.37; PPL 0.20–0.23; PeH 0.23–0.25; PPH 0.24–0.25; PeW 0.16–0.19; PPW 0.23–0.27; PI1 58–66; PI2 49–54; MTL 0.50–0.57; TI 77–82 (9 measured).

Male
Rigato (2011) - TL 3.1–3.4; HL 0.55–0.56; HW 0.47–0.48; CI 85–86; SL 0.17–0.20; SI 36–42; AL 1.05–1.12; ScW 0.50–0.54; MnL 0.74–0.77; PeL 0.31–0.34; PPL 0.19–0.20; PeH 0.20–0.21; PPH 0.19–0.20; PeW 0.16–0.17; PPW 0.21–0.23; PI1 59–62; PI2 66–71; MTL 0.60–0.64; TI 128–133 (3 measured).

Type Material
Rigato (2011) - 2 syntype workers and 1 dealate gyne, ITALY: Capodimonte [Naples], 30.iii.[18]72 (C. Emery) [not examined]. 1 syntype alate gyne, ITALY: PIEMONTE “776” [handwritten by Gribodo] (Gribodo) [not examined].

References based on Global Ant Biodiversity Informatics

 * AntArea. Accessed on February 5th 2014 at http://antarea.fr/fourmi/
 * Antarea (at www.antarea.fr on June 11th 2017)
 * Bernadou A., V. Fourcassié, and X. Espadaler. 2013. A preliminary checklist of the ants (Hymenoptera, Formicidae) of Andorra. Zookeys 277: 13-23.
 * 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.
 * Bracko G. 2007. Checklist of the ants of Slovenia (Hymenoptera: Formicidae). Natura Sloveniae 9: 15-24
 * Bracko, G. 2006. Review of the ant fauna (Hymenoptera:Formicidae) of Croatia. Acta Entomologica Slovenica 14(2): 131-156.
 * Casevitz-Weulersse J., and C. Galkowski. 2009. Liste actualisee des Fourmis de France (Hymenoptera, Formicidae). Bull. Soc. Entomol. Fr. 114: 475-510.
 * DuBois, M. B. "A revision of the ant genus Stenamma in the Palaeartic and Oriental regions." Sociobiology 32 (1998): 193-403.
 * Dubovikoff D. A., and Z. M. Yusupov. 2018. Family Formicidae - Ants. In Belokobylskij S. A. and A. S. Lelej: Annotated catalogue of the Hymenoptera of Russia. Proceedingss of the Zoological Institute of the Russian Academy of Sciences 6: 197-210.
 * Emery C. 1916. Fauna entomologica italiana. I. Hymenoptera.-Formicidae. Bullettino della Società Entomologica Italiana 47: 79-275.
 * Espadaler X., F. Garcia, X. Roig, and R. Vila. 2013. Ants (Hymenoptera, Formicidae) from the Castell de Montesquiu park (Osona, north-east of the Iberian Peninsula). Boletín de la Sociedad Entomológica Aragonesa (S.E.A.) 53: 223-227.
 * Espadaler, X., J. Pujade-Villar, and A. Bernadou. "Contribució al coneixement de la taxonomia i la fenologia de les formigues (Hymenoptera: Formicidae) d'Andorra." Butlletí de l' Institució Catalana d'Història Natural 74 (2006): 81-90.
 * Espadaler, X., and J. M. Riasol. "Distribución, variabilidad y sinonimias en Aphaenogaster iberica Emery, 1908 y dos adiciones a la fauna ibérica." Actas del I Congreso Ibérico de Entomología I (1983): 219-228.
 * Espadaler, X. "Catàleg de les formigues del països catalans." Ses. Entomol. ICHN-SCL IX (1997): 23-42.
 * Finzi, B. "Formiche dell'isola d'Elba e Monte Argentario." Bollettino della Società Entomologica Italiana 56 (1924): 12-15.
 * GRETIA. 2017. Bilan annuel de l'enquete sur la repartition des fourmis armoricaines. 23 pages.
 * Galkowski C. 2008. Quelques fourmis nouvelles ou intéressantes pour la faune de France (Hymenoptera, Formicidae). Bulletin de la Société Linnéenne de Bordeaux, 143, N.S. 36, 4 : 423-433.
 * Giacalone I., and M. Moretti. 2001. Contributo alla conoscenza della mirmecofauna (Hymenoptera: Formicidae) dei castagneti al Sud delle Alpi (ticino, Svizzera). Bollettino della Societa ticinese di Scienze naturali 89(1-2): 51-60.
 * Gouraud C. 2015. Bilan de l’année 2014 : Atlas des fourmis de Loire-Atlantique (Hymenoptera, Formicidae). Atlas des Formicidae de Loire-Atlantique, compte rendu de la première année d’étude (2014)
 * Grandi G. 1935. Contributi alla conoscenza degli Imenotteri Aculeati. XV. Boll. R. Ist. Entomol. Univ. Studi Bologna 8: 27-121.
 * Hosoishi, S., S. Yamane and K. Ogata. 2010. Subterranean species of the ant genus Crematogaster in Asia (Hymenoptera: Formicidae). Entomological Science 13:345-350.
 * Kiran K., and C. Karaman. 2012. First annotated checklist of the ant fauna of Turkey (Hymenoptera: Formicidae). Zootaxa 3548: 1-38.
 * Lebas C., C. Galkowski, P. Wegnez, X. Espadaler, and R. Blatrix. 2015. The exceptional diversity of ants on mount Coronat (Pyrénées-Orientales), and Temnothorax gredosi(Hymenoptera, Formicidae) new to France. R.A.R.E., T. XXIV (1): 24  33
 * Liu X., and Z. H. Xu. 2011. Three New Species of the Ant Genus Stenamma (Hymenoptera: Formicidae) from Himalaya and the Hengduan Mountains With a Revised Key to the Known Species of the Palaearctic and Oriental Regions. Sociobiology 58: 733-748.
 * Mei, M. "Su alcune specie endogee o criptobiotiche della mirmecofauna italiana." Fragmenta Entomologica 23 (1992): 411-422.
 * Moretti M. P. Duelli, and M. K. Obrist. 2006. Biodiversity and resilience of arthropod communities after fire disturbance in temperate forests. Oecologia 149: 312327.
 * Müller, G. "Le formiche della Venezia Guilia e della Dalmazia." Bollettino della Società Adriatica di Scienze Naturali in Trieste 28 (1923): 11-180.
 * Neumeyer R., and B. Seifert. 2005. Commented check list of free living ant (Hymenoptera: Formicidae) species of Switzerland. Bulletin de la Societe Entomologique Suisse 78: 1-17.
 * Ottonetti L., L. Tucci, and G. Santini. 2006. Recolonization Patterns of Ants in a Rehabilitated Lignite Mine in Central Italy: Potential for the Use of Mediterranean Ants as Indicators of Restoration Processes. Restoration Ecology 14(1): 6066.
 * Petrov I. 2010. Contribution to the myrmecofauna (Hymenoptera: Formicidae) of some parts of the Adriatic coast and some islands in Croatia. Acta Entomologica Serbica 15(2): 269-272
 * Petrov I. Z., and C. A. Collingwood. 1992. Survey of the myrmecofauna (Formicidae, Hymenoptera) of Yugoslavia. Archives of Biological Sciences (Belgrade) 44: 79-91.
 * Poldi B., M. Mei, and F. Rigato. 1995. Hymenoptera, Formicidae. Vol 102. Checklist delle specie della fauna Italiana: 1-10.
 * Rigato F. 2011. Contributions to the taxonomy of West European and North African Stenamma of the westwoodii species-group. (Hymenoptera Formicidae). Memorie della Società Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano 37: 1-56.