Temnothorax angustifrons

Recently described from several localities in western Turkey and only one Greek locality in Sterea Ellas (Csősz et al. 2015). Several new localities were recorded from Samos (Borowiec & Salata 2018c). Nests were observed under moss on stones in shadow places close to streams or under the canopy of trees. Numerous localities from Lesbos confirmed opinion by Borowiec & Salata (2018c) that this is the commonest species of Temnothorax nylanderi group in the East Aegean Islands. (Salata & Borowiec, L., 2018)

Identification
Csösz et al. (2015) - A member of the angustifrons species-complex. This species has the longest scape (SL/CS) and the narrowest frons (FRS/CS) of all species treated in this revision. Temnothorax angustifrons strikingly resembles other members of this complex in Turkey. Therefore, the above specified characters may slightly overlap, but a simple ratio of their combination (FRS/SL) provides an excellent tool to separate this species from its relatives with an error rate of less than 5% for single individuals.

Simple ratios of the above-mentioned morphometric traits (SL/CS and FRS/CS) also separate T. angustifrons from other species belonging to other species complexes in Turkey.

Distribution
This species is known from Western Anatolia, Turkey. Its occurrence in Stenos, Greece, might be ascribed to anthropochory.

This is a common species in the Aegean Islands and with a single record from Sterea Ellas. New to Thrace (Borowiec et al., 2022).

Distribution based on Regional Taxon Lists
Palaearctic Region: Greece, Turkey.

Nomenclature

 *  angustifrons. Temnothorax angustifrons Csösz, Heinze & Mikó, 2015: 18, figs. 9A-C (w.) TURKEY.

Worker
Body color: yellow. Body color pattern: mesosoma, antenna and legs, waist and anterior region of 1st gastral tergite lighter than head dorsum and posterior region of gaster. Antennomere count: 12. Antenna color pattern: clava concolorous funicle. Absolute cephalic size: 500–590 μm (mean = 546, n = 16). Cephalic length vs. Maximum width of head capsule (CL/CWb): 1.193–1.254 (mean = 1.224). Postocular distance vs. cephalic length (PoOc/CL): 0.377–0.401 (mean = 0.389). Postocular sides of cranium contour frontal view orientation: converging posteriorly. Postocular sides of cranium contour frontal view shape: convex. Vertex contour line in frontal view shape: straight. Vertex sculpture: main sculpture dispersed forked costate, ground sculpture inconspicuous areolate. Genae contour from anterior view orientation: converging. Gena contour line in frontal view shape: feebly convex. Gena sculpture: rugoso-reticulate with feeble areolate ground sculpture. Median region of antennal rim vs. frontal carina in frontal view structure: not fully overlapped by frontal carina. Concentric carinae laterally surrounding antennal foramen count: present. Eye length vs. absolute cephalic size (EL/CS): 0.247–0.263 (mean = 0.254). Frontal carina distance vs. absolute cephalic size (FRS/CS): 0.320–0.349 (mean = 0.328). Longitudinal carinae on median region of frons count: present; absent. Longitudinal carinae on medial region of frons shape: forked. Smooth median region on frons count: present. Scape length vs. absolute cephalic size (SL/CS): 0.807–0.832 (mean = 0.821). Facial area of the scape absolute setal angle: 0–15°. External area of the scape absolute setal angle: 30°. Ground sculpture of submedian area of clypeus: smooth. Median carina of clypeus count: present. Lateral carinae of clypeus count: present. Median anatomical line of propodeal spine angle value to Weber length in lateral view: 50–55°. Spine length vs. absolute cephalic size (SPST/CS): 0.200–0.264 (mean = 0.231). Minimum spine distance vs. absolute cephalic size (SPBA/CS): 0.242–0.275 (mean = 0.259). Maximum spine distance vs. absolute cephalic size (SPWI/CS): 0.282–0.319 (mean = 0.298). Apical spine distance vs. absolute cephalic size (SPTI/CS): 0.265–0.298 (mean = 0.284). Maximum mesosoma width vs. absolute cephalic size (MW/CS): 0.588–0.620 (mean = 0.601). Metanotal depression count: present. Metanotal depression shape: deep. Dorsal region of mesosoma sculpture: areolate ground sculpture, superimposed by dispersed rugae. Lateral region of pronotum sculpture: areolate ground sculpture, main sculpture dispersed costate. Mesopleuron sculpture: areolate ground sculpture superimposed by dispersed rugulae. Metapleuron sculpture: areolate ground sculpture superimposed by dispersed rugulae. Frontal profile of petiolar node contour line in lateral view shape: straight; concave. Dorsal profile of petiolar node contour line angle value to frontal profile of petiole contour line in lateral view: 90–100°. Anterodorsal rim of petiole count: absent medially. Dorsal region of petiole sculpture: ground sculpture areolate, main sculpture dispersed rugose; ground sculpture areolate, main sculpture absent. Dorso-caudal petiolar profile contour line in lateral view shape: straight; concave. Dorsal region of postpetiole sculpture: ground sculpture areolate, main sculpture dispersed rugose; ground sculpture areolate, main sculpture absent.

Queen
Salata and Borowiec (2018) - (n=5): HL: 0.73 ± 0.03 (0.69-0.75); HW: 0.66 ± 0.02 (0.64-0.68); SL: 0.47 ± 0.02 (0.45-0.49); EL: 0.2 ± 0.002 (0.19-0.21); EW: 0.16 ± 0.004 (0.156-0.164); ML: 1.2 ± 0.06 (1.1-1.25); PSL: 0.21 ± 0.01 (0.2-0.23); SDL: 0.16 ± 0.01 (0.14-0.17); PEL: 0.39 ± 0.02 (0.36-0.41); PPL: 0.24 ± 0.01 (0.23-0.26); PEH: 0.31 ± 0.01 (0.3-0.33); PPH: 0.3 ± 0.02 (0.28-0.32); PNW: 0.76 ± 0.02 (0.74-0.79); PEW: 0.23 ± 0.01 (0.22-0.24); PPW: 0.32 ± 0.01 (0.3-0.33); HI: 90.0 ± 2.3 (86.8-92.9); SI1: 64.1 ± 1.8 (62.2-66.4); SI2: 71.3 ± 2.6 (68.2-75.0); MI: 65.3 ± 2.9 (62.2-68.9); EI1: 83.1 ± 2.3 (79.2-84.7); EI2: 22.2 ± 1.2 (20.7-23.8); PI: 131.9 ± 3.3 (128.2-136.1); PPI: 75.4 ± 2.8 (73.7-80.0).

Colour. Whole body dark yellow to orange. Frons and malar area sometimes slightly darker. Head. Trapezoid, lateral surfaces below eyes straight gently rounded on the posterior edges, occipital margin of head convex. Anterior margin of the clypeus gradually convex. Eyes big, oval, 0.3 times as long as length of the head. Antennal scape short, slightly curved, 0.6 times as long as length of the head, not reaching occipital margin of head, in apex gradually widened, its base without teeth. Pedicel more than 2 times longer than wide; average 1.2 times longer than second segment of funiculus. Other funicular segments more than 1 ½times longer than wide. Surface of scape with very fine, short and sparse striae and sparse reticulation; covered with thin, moderate dense, decumbent to erect setae, shorter than 1/3 of scape width. Mandibles oval, with sparse, longitudinal striae, shiny. Clypeus shiny with a few, thick, longitudinal striae at its anterior part, area between striae smooth, shiny. Frontal carinae short, slightly extending across the fronts of the antennal fossae. Antennal fossa deep, with sparse roundly curved striae, area between striation smooth. Frontal lobes narrow, smooth with thick longitudinal striae. Head on the whole surface with moderate thick, dense, longitudinal and interrupted striation, area between striae with irregular, fine and thin rugae, shiny; genae with sculpture reduced or absent. Entire head bearing thick, suberect to erect, pale setae. Mesosoma. Short, square, 1.6 times as long as head; in lateral view its dorsum slightly convex; propodeal spines triangular, short, with wide base, inclined at the 45° angle; dorsal surface of propodeum inclined towards its posterior surface. Pronotum with longitudinal, horizontal, weak but dense striation and reticulation, area between rugae smooth or with microreticulation, shiny. Scutum, scutellum and axilla with longitudinal striation, area between striae smooth or with sparse and fine microreticulation; centre of scutum, scutellum and axilla with reduced or absent sculpture; propodeum shiny, with sparse, thick reticulation on dorsum and weaker and denser sculpture on lateral sides. Anepisternum and katepisternum shiny and smooth with dense and fine reticulation on lateral edges. Mesosoma dorsum with sparse, thick, erect setae. Petiole. Peduncle short, node high and narrow, with anterior and posterior faces convex, its dorsal surface narrow and convex. On the whole surface covered by dense reticulation and sparser thick, irregular striae and long, thick erect setae. Postpetiole. In lateral view, regularly rounded, 0.75 times as long as wide, apical half with gently rounded sides. On the whole surface covered by dense reticulation and sparser thick, irregular striae and long, thick erect setae. Gaster. Smooth and shiny, bearing dense, long, suberect to erect, pale setae.

Type Material
Holotype worker labelled: Turkey, Road Edremit to Kalkun, Kaz Daği Mountain, 39.411 N, 27.093 E, 752mH, 10.05.2003, leg. A. Schulz, “072” ( CASENT0914693), [TUR:Edremit-Kalkun-20030510-072].

Paratypes: Turkey, Road Edremit to Kalkun, Kaz Daği Mountain, 39.411 N, 27.093 E, 752mH, 10.05.2003, leg. A. Schulz, “072” (1# HNHM), [TUR:Edremit-Kalkun-20030510-072]; Turkey, Road Edremit to Kalkun, Kaz Daği Mountain, 39.411 N, 27.093 E, 752mH, 10.05.2003, leg. A. Schulz, “076” (2## HNHM), [TUR:Edremit-Kalkun-20030510-076].

Etymology
The species name refers to the frons, which is narrow (Latin: angustus m) relative to other Temnothorax species treated in this revision.

References based on Global Ant Biodiversity Informatics

 * Borowiec L., and S. Salata. 2018. Notes on ants (Hymenoptera: Formicidae) of Samos Island, Greece. Annals of the Upper Silesian Museum in Bytom Entomology 27: 1-13.
 * Csősz S, Heinze J, and I. Mikó. 2015. Taxonomic synopsis of the Ponto-Mediterranean ants of Temnothorax nylanderi species-group. PLoS ONE 10(11): e0140000. doi:10.1371/journal.pone.0140000
 * Salata S., and L Borowiec. 2017. Species of Tetramorium semilaeve complex from Balkans and western Turkey, with description of two new species of (Hymenoptera: Formicidae: Myrmicinae). Annales Zoologici (Warsaw) 62:279–313.
 * Salata S., and L. Borowiec. 2018. Taxonomic and faunistic notes on Greek ants (Hymenoptera: Formicidae). Annals of the Upper Silesian Museum in Bytom Entomology 27: 1-51.