Temnothorax arkasi, Salata & Borowiec, 2022

Salata, Sebastian & Borowiec, Lech, 2022, A review of the Temnothorax anodontoides species-group (Hymenoptera, Formicidae) from Greece, ZooKeys 1091, pp. 139-159 : 139

Temnothorax arkasi sp. nov.

Figs 1-2 , 3 , 7 , 19

Type material.

Holotype: worker (CASENT4015000, pin), label: "Greece, Peloponnes | Prov. Arkadia | A. Schulz & K. Vock lgt. || Parnon, | 3 km W Sitena | 37°18'N, 22°36'E | 25.4.2000 1700 m || Collection L. Borowiec | Formicidae | LBC-GR02714" (MNHW-DBET). Paratypes: 3 workers (CASENT4015001-CASENT4015003): the same data as holotype; 5 workers (CASENT4015004-CASENT4015008): the same data as holotype + "Sample Nr. | AS1"; 8 workers (CASENT4015009-CASENT4015016): the same data as holotype + "Sample Nr. | AS2"; 6 workers (CASENT4015017-CASENT4015022): the same data as holotype + "Sample Nr. | AS3" (MHNG, MNHW-DBET, PW).

Type locality.

Greece, Peloponnes Province, Parnon, 3 km W Sitena, 37.3/22.6, 1375 m a.s.l.

Differential diagnosis.

Temnothorax arkasi differs from T. parnonensis and T. anodontoides in very dark body coloration, with head and mesosoma predominantly dark brown to black (pale brown to yellowish brown in both relatives) and more elongate head, i.e., 1.25-1.28 as long as wide (only 1.22 in both relatives); from T. anodontoides it differs additionally in more sculptured head with rugulocostulate frontal part of head ( T. anodontoides has frons entirely rugulate); from T. parnonensis it additionally differs in reduced propodeal spines and lack of smooth patch on frons ( T. parnonensis has small but well-marked triangular propodeal spines and its frons sculpture is reduced on the central part); from T. euboeae it differs in almost reduced propodeal spines that are in form of small angulation of very short triangular spines, shiny interspaces between head sculpture, and longer petiole with moderately elongate pedicel ( T. euboeae has propodeal spines distinct and in form of small, short, needles, more dull head surface and very short pedicel); from T. ikarosi it differs in more elongate head, shorter petiolar peduncle, denser and thinner sculpture on promesonotal dorsum and smaller propodeal spines ( T. ikarosi has less elongate head, longer petiolar peduncle, sparser and thicker promesonotal sculpture and bigger propodeal spines).

Description.

Worker (N = 10): HL: 0.66 ± 0.03 (0.6-0.71); HW: 0.55 ± 0.03 (0.5-0.57); SL: 0.49 ± 0.03 (0.44-0.53); EL: 0.14 ± 0.01 (0.11-0.16); EW: 0.1 ± 0.01 (0.08-0.12); WL: 0.8 ± 0.06 (0.68-0.89); PSL: 0.12 ± 0.01 (0.11-0.13); SDL: 0.11 ± 0.01 (0.1-0.12); PEL: 0.29 ± 0.03 (0.24-0.34); PPL: 0.17 ± 0.01 (0.15-0.19); PEH: 0.2 ± 0.02 (0.17-0.23); PPH: 0.19 ± 0.01 (0.17-0.21); PNW: 0.39 ± 0.02 (0.36-0.42); PEW: 0.18 ± 0.01 (0.15-0.19); PPW: 0.22 ± 0.02 (0.2-0.24); CI: 1.2 ± 0.03 (1.18-1.25); SI1: 0.74 ± 0.03 (0.68-0.77); SI2: 0.9 ± 0.03 (0.82-0.94); MI: 0.49 ± 0.03 (0.45-0.54); EI1: 0.75 ± 0.06 (0.67-0.85); EI2: 0.16 ± 0.01 (0.13-0.17); PI: 1.43 ± 0.1 (1.26-1.59); PPI: 0.87 ± 0.04 (0.8-0.94); PSI: 1.1 ± 0.03 (1.08-1.18).

Colour. Head dark brown, mesosoma, petiole and postpetiole brown to brownish black, lateral sides of pronotum with indistinct brownish areas, gaster mostly brown only base of first segment slightly brighter, in the palest specimens mesosoma partly yellowish brown; scape yellowish to yellowish brown, funicle segments 1-8 yellowish, antennal club yellowish brown to dark brown, legs mostly yellowish to yellowish brown, femora medially darkened (Figs 1 , 2 ). Head. Slightly elongate, 1.28 times as long as wide, sides below and above eyes gently convex, occipital corners regularly rounded, occipital margin of head straight (Figs 3 , 7 ). Anterior margin of clypeus distinctly convex, medial notch absent. Eyes moderate, short oval, 1.2 times as long as wide. Antennal scape short, in lateral view slightly curved, 0.78 times as long as length of the head, in apex gradually widened, its base without tooth, funiculus long, club 3-segmented (Fig. 3 ). Surface of scape finely microreticulate, shiny, covered with thin, dense, decumbent to suberect setae. Funicle longer than scape, first segment 2.1 times as long as wide at apex, segments 2-7 short, rectangular. Mandibles rounded with thick and sparse striae, shiny. Clypeus with sharp median longitudinal keel and two keels laterally, area between keels microreticulate but shiny. Frontal carinae short, slightly extending beyond frontal lobes. Antennal fossa deep, with thin circular striae and dense microreticulation. Frontal lobes narrow, microreticulate with costulae (Fig. 7 ). Frons, gena, malar region, vertex and temples densely reticulate with shiny interspaces; frons, gena, area behind eyes, central part of vertex, occipital area with additional costulae, malar area with costulae partly interrupted. Whole surface of head appears shiny. Sides of head with very short and sparse adpressed pubescence, sides of frons, vertex and occipital area with erect, pale, short and thick setae (Figs 3 , 7 ). Mesosoma. Elongate, approximately twice as long as wide, distinctly arched in profile. Metanotal groove absent. Pronotum convex on sides. Propodeal spines very short, in form of triangular denticles or small angulation (Fig. 2 ). Whole surface of mesosoma densely reticulate with shiny interspaces. Pronotal dorsum regulate, lateral sides of pronotum rugocostulate, mesonotal dorsum reticulocostulate, propodeum rugocostulate, area below spines microreticulate with few transverse costulae. Entire mesosoma with erect, pale, moderately long and thick setae (Figs 1 , 2 ). Petiole. In lateral view, with moderately elongate peduncle, node low, with anterior face shallowly concave and dorsum regularly rounded, whole surface rugoreticulate. Dorsal surface with sparse, short, erect setae. Postpetiole. In lateral view regularly convex, sides rounded, on the whole surface reticulocostulate, surface appears less rugose than surface of petiole. Dorsal surface with sparse, moderately long, erect setae (Figs 1 , 2 ). Gaster. Smooth and shiny, with erect, thin, pale setae (Figs 1 , 2 ). Legs. Moderately elongate, femora swollen in the middle, tibiae widened from base to ¾ length, surface of legs covered with sparse, adpressed to decumbent hairs.

Etymology.

The name is a noun in genitive case, dedicated to Arkás (ancient Greek: Ἀρκάς), a mythological hunter and King of ancient Arkadía (ancient Greek: Ἀρκαδία). His name was given to the recent Greek province Arcadia, Peloponnese, a terra typica for Temnothorax arkasi .

Biology.

The type locality is placed in an alpine zone on the rocky northern slopes of Mt. Parnon overgrown with a young and sparse fir forest. The altitude indicated on the labels (1700 m) is most likely overestimated as the site indicated by the geographical coordinates given on the label gives the actual altitude of 1375 m.

Figures

Figure 19. Distribution of members of the Temnothorax anodontoides species-group in Europe: Temnothorax arkasi (red circle), T. euboeae (violet circle), T. ikarosi (orange circle), T. parnonensis (green circles) and T. saxatilis (blue circle).

Figures 1, 2. Holotype worker of Temnothorax arkasi sp. nov. 1 dorsal 2 lateral. Scale bar: 1 mm.

Figures 3, 4. Head and antennae of holotype workers 3 Temnothorax arkasi sp. nov. 4 Temnothorax euboeae sp. nov. Scale bars: 0.25 mm.

Figures 7, 8. Head sculpture of holotype workers 7 Temnothorax arkasi sp. nov. 8 Temnothorax euboeae sp. nov.