Temnothorax curtisetosus

We found only two workers of Temnothorax curtisetosus in a nest of Temnothorax antigoni. The large number of gynes in relation to number of workers of the host species (5 gynes/6 workers) suggests that the nest was in the initial stage. (Salata and Borowiec 2015)

Identification
A member of the Temnothorax muellerianus group.

Salata and Borowiec (2015) - Both specimens of this parasite have constant characters, especially very short dorsal setae. Very small specimens of Temnothorax muellerianus have dorsal setae proportionally 1.5 times longer than both specimens of T. curtisetosus. Kutter (1973) and Buschinger et al. (1988), basing on a large material from the entire Mediterranean basin, discussed variability and status of several taxa closely related to T. muellerianus but none of the samples studied by them were characterized by short dorsal setae. Although we have only two specimens of T. curtisetosus, the clear gap in the length of dorsal setae between these specimens and all examined samples of T. muellerianus (37 workers from 12 localities of 4 countries, see Suppl. material 1), a shorter propodeal spines and the analysis of variability within various populations of T. muellerianus discussed by Buschinger et al. (1988) convinced us to describe these two specimens as a species new for science.

Temnothorax curtisetosus belongs to a monophyletic group of social parasites formerly classified as a separate genus Chalepoxenus and recently synonymized with Temnothorax (Ward et al. 2015). The group comprises five species in Europe and the Mediterranean subregion, all are parasites of various Temnothorax species: Temnothorax brunneus from Morocco, Temnothorax kutteri from France: mainland, and Spain: mainland, Temnothorax muellerianus from Bulgaria, Croatia, Cyprus, France: mainland, Germany, Greece: Crete, Ionian Is., mainland, Sicily, Portugal, Serbia, Slovenia, Spain: mainland, Switzerland, Turkey and Ukraine, Temnothorax inquilinus from Ukraine and Temnothorax tramieri from Morocco.

Temnothorax curtisetosus and T. muellerianus differ significantly from other members of this group in having tibiae covered with long, erect setae. Temnothorax muellerianus is the most widely distributed and the most variable species of this group (Buschinger et al. 1988). Temnothorax curtisetosus distinctly differs from T. muellerianus in very short setae on the mesosoma, petiole and postpetiole, and especially on gastral tergites (the total length of 10 setae combined on the first tergite is 741 μm in T. curtisetosus vs. 1111-1325 μm in T. muellerianus). Temnothorax curtisetosus is smaller than most specimens of T. muellerianus and has shorter antennal scapes and higher SI index. At the first glance T. curtisetosus reminds a workers of Temnothorax finzii. Besides a clear differences in the biology of these species, T. finzii is a non-parasitic species inhabiting dry open habitats and nesting deep in the soil, usually under stone (Bračko et al. 2014), these species can be distinguished also in morphological features. T. curtisetosus differs from T. finzii by a weaker longitudinal striation covering only sides of the frons and its head is devoid of rugosity (in T. finzii whole head is covered by longitudinal striation with rugosity between it) and in presence of a dentiform plate on the ventral margin of the petiole, a character associated with a Chalepoxenus line. Moreover T. curtisetosus has also smaller propodeal spines (SPI < 31.7 vs SPI>40.8 in T. finzii).

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

Nomenclature

 *  curtisetosus. Temnothorax curtisetosus Salata & Borowiec, 2015c: 140, figs. 9-11, 12, 14 (w.) TURKEY.

Worker
(n = 2). HL: 0.715-0.737 (0.726); HW: 0.536-0.570 (0.553); EL: 0.178-0.184 (0.181); EW: 0.145-0.151 (0.148); SL: 0.575- 0.603 (0.589); ML: 0.899-0.905 (0.902); PSL: 0.162-0.170 (0.166); PL: 0.296-0.330 (0.313); PPL: 0.212-0.235 (0.2235); PH: 0.279-0.279 (0.279); PPH: 0.223-0.246 (0.2345); SPBA: 0.201-0.190 (0.1955); SPT: 0.229-0.223 (0.226); PW: 0.212-0.235 (0.2235); PPW: 0.313-0.313 (0.313); HI: 75-77.3 (76.2); EI: 24.9-25 (24.95); SPI 28.4-31.7 (30.1); SI: 80.4-81.8 (81.1).

Head yellowish, in dorsal half slightly darker than in frontal parts and below eyes. Mesosoma, petiole, postpetiole, antennae and legs uniformly yellowish, first gastral tergite yellowish-brown with paler large patch at base, subsequent tergites yellowish-brown, sternites yellow.

Head 1.4 times as long as wide, posterior margin of head straight and laterally rounded in full-face view, gena almost parallel-sided. Eyes moderately large, 1.2 times as long as wide, gena 1.2 times as long as eye length, distance between line connecting hind margins of eyes to posterior margin of head 1.3 times as long as eye length. Anterior margin of clypeus regularly rounded, clypeal lines distinct, slightly divergent, reaching to the line connecting posterior margin of eyes. Almost whole surface of head smooth and shiny, only gena with rugose sculpture and along inner and outer margin of eye run 2–3 thin carinae. Clypeus, frons and top of the head with numerous, moderately long, erect hair, the longest hairs slightly shorter than eye width, ventral surface of head with numerous moderately long hairs. Antennal scape 0.8 times as long as head, thin, in widest part only 1.5 times as wide as antennal base. Surface of scape smooth and shiny, covered with moderately long, moderately dense, more or less erect hairs. Funiculus 1.3 times as long as scape with three-segmented thin club, first segment 1.8 times as long as wide, second segment as long as wide, segments 3–5 slightly transverse, club very long, only slightly shorter than segments 1–9 combined. Mesosoma elongate, 2.5 times as long as wide, with deep metanotal groove. Pronotum rounded on sides, regularly convex in profile, smooth and shiny, with 5–6 moderately long and few short, erect hairs. Promesonotal suture very fine but visible, mesonotum forms with pronotum regular arch, dorsal surface smooth and shiny with 4–8 moderately long hairs, sides with few longitudinal carinae. Mesopleura with indistinct microreticularion and few carinae. Propodeum distinctly convex in profile, surface with indistinct microreticulation but shiny, with 5–6 moderately long erect setae, propodeal spines short, 1.1 times as long as width at base, acute, near apex with one long seta, metapleura with indistinct microreticularion and few carinae. Petiole short, 1.1 times as long as high, dorsal surface shallowly concave, petiolar lobe rounded, on sides with short carina, ventral margin of petiole straight, carinate, at base with moderately large, sharp denticle. In dorsal view petiolar lobe almost round, then distinctly converging to base. Petiolar lobe smooth and shiny with 4 long and two short erect hairs, sides of petiole microreticulate but shiny. Postpetiole globular in profile, from dorsal view distinctly transverse, 1.4 times as wide as long, with regularly rounded sides, top of postpetiole smooth and shiny with 8–10 moderately long, erect hair, sides microreticulate with few short carinae. Gaster slightly shorter than mesosoma, surface smooth and shiny covered with numerous moderately long, erect hairs. Legs elongate, smooth and shiny, with sparse, semierect to erect hairs, femora along underside with row of 3–4 long erect hairs. Hind tarsus 1.4 times as long as hind tibia.

Type Material
Holotype worker ( no. 1226): TURKEY, Antalya Prov. ancient Phaselis c. 6 m, 36.5262N/30.5455E 29 VI 2010, L. Borowiec Collection L. Borowiec Formicidae LBC-TR00059 Temnothorax curtisetosus sp. n. in nest of T. antigoni det. Salata & Borowiec; paratype worker: the same data as holotype.

Etymology
Named after the very short setae on mesosoma dorsum and gastral tergites.