Temnothorax pilagens, Seifert, Bernhard, Kleeberg, Isabelle, Feldmeyer, Barbara, Pamminger, Tobias, Jongepier, Evelien & Foitzik, Susanne, 2014

Seifert, Bernhard, Kleeberg, Isabelle, Feldmeyer, Barbara, Pamminger, Tobias, Jongepier, Evelien & Foitzik, Susanne, 2014, Temnothorax pilagens sp. n. - a new slave-making species of the tribe Formicoxenini from North America (Hymenoptera, Formicidae), ZooKeys 368, pp. 65-77 : 68-69

Temnothorax pilagens sp. n.

Etymology.

The species epithet refers to the slave raiding behaviour of the new ant species (from Latin: pilare, English: to pluck, plunder, pillage).

Description and differential diagnosis.

The differential diagnosis is done in relation to the congeneric slave-making species Temnothorax duloticus . Measurements and indices in the text of description are the arithmetic means of the whole samples (for full data see Table 1).

Worker (Figs 1, 3 and 5, Table 1): Body size close to the genus average of Temnothorax , mean CS 645 µm. Head relatively broader [CL/CW 1.048 but 1.078 in Temnothorax duloticus ], in dorsal aspect with strongly convex postocular sides and nearly linear, converging genae. Postocular distance smaller [PoOc/CL 0.364 but 0.394 in Temnothorax duloticus ]. Antennae with 11 segments only, scape strikingly shorter [SL/CS 0.721 but 0.801 in Temnothorax duloticus ]. Vertex finely longitudinally rugulose, distance between rugulae on central vertex 12 µm. The rugulae are connected by very delicate transverse anastomosae, which have on central vertex a mean distance of 12-14 µm. Clypeus finely longitudinally carinulate and in full-face view with straight or feebly emarginated anteromedian margin. Only the apical and subapical dent of the masticatory margin of the mandibles are fully developed and acute, the following dents are reduced to an undulating line of 3-6 shallow waves [in Temnothorax duloticus at least the first three dents are fully developed and the whole dentition is more similar to the normal Temnothorax situation]. Genae each with 2-6 semi-erect to erect setae [these are absent in Temnothorax duloticus ]. Mesosoma massive, in lateral view with strongly convex dorsal profile, appearing hump-backed - i.e., much more compact and shorter than in Temnothorax duloticus [ML/CS 1.174 but 1.272 in Temnothorax duloticus ]. Spines significantly shorter and thicker [SPST/CS 0.364 and SP/CS 0.300 but 0.425 and 0.361 respectively in Temnothorax duloticus ]; spines in lateral view semi-erect, deviating from longitudinal axis of the mesosoma by 27-35°; in dorsal view diverging by 36-39° and with a larger basal distance [SPBA/CS 0.382, but 0.317 in Temnothorax duloticus ]. The entire mesosoma exhibits a rugulose-microreticulate sculpture. Petiolar node in lateral view with a straight or weakly concave frontal profile forming with the short dorsal plane an angle of 81-91°; caudal petiolar profile steeply but linearly sloping down to junction with postpetiole [in Temnothorax duloticus there is a distinct step in the caudal slope caused by a prolongation of the caudal cylindric part of petiole]. Petiole clearly shorter [PEL/CS 0.452 but 0.517 in Temnothorax duloticus ]. Postpetiolar sternite in lateral view with a strongly developed, triangular dent, directed anteroventrad, comparable to situation in Temnothorax duloticus . Dorsum of petiole node in dorsal view 1.7-2.0 fold wider than long, postpetiole in dorsal view roughly trapezoidal and much wider than in any independent Temnothorax species, PPW/CS 0.491. Whole surface of petiolar and postpetiolar nodes coarsely microreticulate. Surface of 1st gaster tergite smooth and shining, but with a very delicate (sculpture lines only 0.5 µm thick), patchily missing microreticulum [in Temnothorax duloticus there is nowhere a connected microreticulum - it is reduced to isolated, scattered structures in the form of an “X” or of a matchstick man]. All dorsal body surfaces with setae of medium length. Dorsal head dark brown. Mesosoma, waist and appendages yellowish, propodeum, meso- and metapleuron sometimes darker brownish. Gaster tergites yellowish, often with small brown bands at posterior margin; the first tergite usually shows big brown patches on each side that may fuse medially in some specimens, then covering 70% of total surface.

Gyne (only one gyne was evaluated in both Temnothorax pilagens sp. n. and Temnothorax duloticus ): Head size similar to the genus average of Temnothorax , mean CS 673 µm. Head very short [CL/CW 0.982 but 1.044 in Temnothorax duloticus ], in full-face view with strongly convex postocular sides, a feebly concave occipital margin and linear, converging genae. Postocular distance very short [PoOc/CL 0.341 but 0.401 in Temnothorax duloticus ]. Antennae with 11 segments only, scape very short [SL/CS 0.683 but 0.748 in Temnothorax duloticus ]. Vertex longitudinally rugulose, distance between rugulae on central vertex 15 µm, the interspaces between rugulae with reticulate microsculpture. Clypeus finely longitudinally carinulate and in full-face view with feebly notched anteromedian margin. The three apical dents of the mandibular masticatory margin are fully developed and acute, the following four dents are reduced to denticles. Mesomoma very small for Temnothorax in general, but not smaller than in Temnothorax duloticus [ML/CS 1.484, MW/CS 0.904, MH/CS 0.868]. Spines well-developed and acute but significantly shorter and relatively thicker than in Temnothorax duloticus [SPST/CS 0.364 and SP/CS 0.265 but 0.457 and 0.360 respectively in Temnothorax duloticus ]; spines in lateral view very weakly erected, deviating from longitudinal axis of mesosoma by 20°; in dorsal view with a very large basal distance and weakly diverging [SPBA/CS 0.482, SPTI/CS 0.479; in Temnothorax duloticus more clearly diverging, SPBA/CS 0.434 and SPTI/CS 0.530]. Whole mesosoma with rugose-microreticulate sculpture that is on mesonotum and mesopleuron less developed. Petiolar node in lateral view very high and with a weakly concave frontal profile forming with the short dorsal plane an angle of 80°; caudal petiolar profile steeply and almost linearly sloping down to junction with postpetiole [in Temnothorax duloticus there is a distinct step in the caudal slope caused by a significant prolongation of the caudal cylindric part of petiole]. Petiole clearly shorter than in Temnothorax duloticus [PEL/CS 0.496 vs. 0.551]. Postpetiolar sternite in lateral view with a strongly developed, triangular dent, directed anteroventrad, comparable to situation in Temnothorax duloticus . Dorsum of petiole node in dorsal view 1.9fold wider than long, postpetiole in dorsal view broadly cordate and much wider than in any independent Temnothorax species, PPW/CS 0.491. Whole surface of petiolar and postpetiolar nodes strongly microreticulate. Surface of 1st gaster tergite smooth and shining but with a very delicate (sculpture lines only 0.5 µm thick), patchily missing microreticulum [in Temnothorax duloticus the microreticulum more incomplete - frequently reduced to isolated, scattered structures in the form of an “X” or of a matchstick man]. All dorsal body surfaces with setae of medium length, the longest on occiput are 74 µm long. Head, mesosoma and waist brown, appendages yellowish to yellowish brown. Gaster tergites yellowish brown, a lighter yellowish patch is at the base of 1st tergite.