Lasius tapinomoides

Species inhabiting moist, closed canopy forests, which are most often located in stream valleys. Nesting in wet soil, under shallow and small rocks. Nests, most often, located in the vicinity of water sources. Workers were found in the litter or on the rocks surrounding the nest entrance. Colonies monogynous.

Identification
Salata and Borowiec (2018) - Worker. As a member of the Lasius alienus group it is characterized by dorsal plane of scape, genae, and extensor profile of hind tibiae lacking or having very few erect or suberect setae and, in all species known from Crete, presence of >15 erect setae on the occipital edge of the head. Within the L. alienus group it can be classified to the Lasius turcicus complex. This complex can be characterized by small number of mandibular teeth (6–8), usually lack of suberect setae on hind tibia, very sparse clypeal pubescence, and more or less shallow metanotal groove. There are three known species of this complex: L. turcicus, Lasius neglectus and Lasius austriacus. Lasius tapinomoides differs from all of them in presence of suberect to erect setae on antennal scape covering its apical part (ca. 1/3 upper part of the scape). Additionally from first two relatives it differs also in very shallow metanotal groove and from L. austriacus it differs in more flattened promesonotum, antennal sockets set not very close to posterior clypeal margin and habitat preferences. Lasius austriacus is related with xerothermous sites (Schlick-Steiner et al. 2003, Steiner et al. 2004) while L. tapinomoides inhabits moist, closed canopy forests.

The shallow metanotal groove of L. tapinomoides is constant in all examined specimens and is always correlated with very small body size of workers and preference to humid habitats. Lasius tapinomoides is the only known member of the L. turcicus complex that have suberect to erect setae on the apical 1/3 part of the antennal scape.

There are two other species of the L. alienus group known from Crete: Lasius bombycina and L. turcicus. Lasius tapinomoides differs from all of them in very small body size. Nevertheless, at the first glance it can be confused with small workers of L. turcicus, from which it differs in the following measurements (L. tapinomoides sp. n. vs L. turcicus): HI: 81.8 ± 3.3 (73.4–85.0) vs 90.2 ± 1.8 (87.2–92.8), SI2: 115.7 ± 4.4 (112.2–127.6) vs 104.7 ± 3.6 (97.3–109.3), TI: 82.0 ± 2.6 (75.8–85.2) vs TI: 89.2 ± 2.2 (85.4–93.8). For more measurements data see Table in Salata and Borowiec, 2018.

Distribution
Known only from Crete.

Distribution based on Regional Taxon Lists
Palaearctic Region: Greece.

Nomenclature

 *  tapinomoides. Lasius tapinomoides Salata & Borowiec, 2018: 142, figs. 1-7 (w.q.) GREECE.

Worker
Head, mesosoma, petiole and gaster uniformly coloured, brown to dark brown. Antennae, tibiae and tarsi bright brown to orange.

Head oval, 1.2 times as wide as long, lateral surfaces above eyes convex, occipital margin of head slightly convex. Clypeus shiny and smooth, its anterior mar¬gin convex, lacking median anterior notch, covered with sparse, decumbent to erect pubescence, average distance between setae longer than three fourths of their length. Masticatory border of mandibles with 7–8 teeth. Eyes medium-sized, oval, 0.25 times as long as length of the head. Antennal scape long, straight or slightly curved on its anterior part, 0.9 times as long as length of the head, exceeding beyond occipital mar¬gin of head, in apex gradually widened. Pedicel more than 2.0 times longer than wide, average 2.5 times longer than second segment of funiculus. Other funicular segments from 1.5 to 2.0 times longer than wide. Surface of scape with very fine mi¬croreticulation, shiny. Its surface covered with thin, dense, adpressed setae, on its apical part several suberect setae also occur.

Genae with few adpressed to suberect setae. Underside of head with thin, dense, adpressed setae and a few long, suberect to erect setae. Whole frontal head surface covered with short, adpressed and dense pubescence and sparse, long, thick suberect to erect setae, the distance between setae at least as long as three fourths of their length.

Mesosoma short, 1.9 times as long as wide. In lateral view, promesonotum low and flattened, metanotal groove very shallow, propodeum very low, propodeal dorsum slightly convex, propodeal declivity convex, less than twice length of propodeal dor¬sum. Whole mesosoma surface shiny with sparse microreticulation, covered with short, adpressed and dense pubescence, and sparse, long, thick suberect to erect setae, the distance between setae at least as long as half of their length, metapleuron below the level of the propodeal spiracle with more than 5 setae.

Petiole scale low, in lateral view with slightly convex sides, its dorsal crest thick and arched. Gaster with very rare and fine microreticulation, shiny, bearing pilosity similar to this covering mesosoma. Legs long, shiny, with fine microreticula¬tion. Surface of tibia and femora with thin, dense, adpressed to subdecumbent setae, extensor profile without erect setae.

Queen
HL: 1.03; HW: 1.2; SL: 0.9; EL: 0.3; EW: 0.24; ML: 2.3; HTL: 1.3; PNW: 1.4; HI: 116.5; SI1: 87.4; SI2: 75; MI: 56.5; EI1: 80; EI2:23; TI: 92.

Head, mesosoma, petiole and gaster dark brown. Antennae, tibiae and tarsi bright brown to orange.

Head trapezoidal, 1.1 times as wide as long, lateral surfaces above eyes convex, sides of occipital margin of head slightly convex, its central part concave. Clypeus shiny and smooth, its anterior margin convex, lacking median anterior notch, covered with decumbent to erect setae, average distance between setae longer than one third of their length. Masticatory border of mandibles with seven teeth. Eyes medium-sized, oval, 0.3 times as long as length of the head. Antennal scape short, curved on its anterior part, 0.9 times as long as length of the head, slightly exceeding beyond occipital margin of head, in apex gradually widened. Pedicel more than 2.0 times longer than wide, 2.0 times longer than second segment of funiculus. Other funicular segments from 1.5 to 2.0 times longer than wide. Surface of scape with very fine microreticulation, shiny. Its surface covered with thin, dense, adpressed to decum¬bent pubescence, on its apical part a few short, suberect setae also occur. Genae with thin, dense adpressed pubescence and a few suberect setae. Underside of head with thin, dense, adpressed pubescence and a few long, suberect setae. Whole frontal head surface covered with short, adpressed and dense pubescence and sparse, long, thick suberect to erect setae, the distance between setae at least as long as three fourths of their length.

Mesosoma long, 1.6 times as long as wide. In lateral view moderately high, its dorsum slightly convex, propodeal dorsum slightly convex, propodeal declivity convex. Whole mesosoma surface shiny with very sparse microreticulation, covered with short, adpressed and dense pubescence, and sparse, long, thick suberect to erect setae, the distance between setae at least as long as half of their length.

Petiole scale low and wide, in lateral view with slightly convex sides, its dorsal crest wide and deeply concave in central part. Gaster with moderately thick and fine microreticulation, shiny, bearing pilosity denser than this covering mesosoma. Legs long, shiny, with fine microreticulation. Surface of tibia and femora with thin, dense, adpressed to subdecumbent setae, extensor profile of tibia with erect setae.

Type Material
Holotype (w.): ‘‘Lasius tapinomoides sp. nov. HOLOTYPE Col¬lection L. Borowiec Formicidae LBC-GR00976 Greece, Crete, Rethym¬no Pr. Antonios Spilia Gorge 35°15.245 N,24°34.220 E 11 V 2013, 342 m L.Borowiec CASENT0845075’’ ; paratypes (6w.,1q.): data same as holo¬type, CASENT0845076 to CASENT0845082 (DBET, NHMC, ); paratypes (15w.), CASENT0845460 to CASENT0845474: ‘‘Greece, Crete, Rethymno Pr. / Kato Malaki / 35.28333 N,24.4 E / 15 V 2013, 235 m / L. Borowiec’’, NHMC, ).

Etymology
The name refers to the similarity of this species to species of the Tap¬inoma genus, caused by a very shallow metanotal groove.