Polyergus sanwaldi, Trager, James C., 2013

Trager, James C., 2013, Global revision of the dulotic ant genus Polyergus (Hymenoptera: Formicidae, Formicinae, Formicini), Zootaxa 3722 (4), pp. 501-548 : 530

Polyergus sanwaldi new species

Figures 42, 43, 44

Holotype worker: USA, NEW YORK Suffolk Co. Medford vicinity. August 1988. R. Sanwald. [CASENT0281058]. Paratypes: 9 gynes, 8 males, 6 workers: same data as holotype [MCZ, CAS, AMNH].

Holotype measurements HL 1.80, HW 1.67, SL 1.60, ½ VeM 15, ½ PnM 4, WL 2.76, GL 2.68, HFL 2.24, CI 93, SI 96, HFI 134, FSI 134, LI 4.56, TL 7.24.

Paratype worker measurements (N=5) HL 1.72–1.80 (1.76), HW 1.63–1.74 (1.70), SL 1.62–1.64 (1.63), ½ VeM 11–15 (12.75), ½ PnM 2–4 (3), WL 2.68–2.83 (2.75), GL 2.12–2.24 (2.19), HFL 2.20–2.32, CI 95–99 (96), SI 93–101 (96), HFI 126–135 (132), FSI 134–143 (137), LI 4.44–4.60 (4.51), TL 6.67–6.76 (6.70).

Measurements (N=31) HL 1.52–1.90 (1.65), HW 1.42–1.80 (1.56), SL 1.50–1.79 (1.60), ½ VeM 3–12 (7.03), ½ PnM 0–4 (1.19), WL 2.36–2.86 (2.55), GL 1.69–2.60 (2.23), HFL 2.08–2.44 (2.20), CI 92–97 (95), SI 97–113 (103), HFI 134–150 (1.41), FSI 124–145 (138), LI 3.88–4.76 (4.20), TL 5.96–7.36 (6.43).

Worker description. Head rounded hexagonal, its length greater than breadth; with conspicuous vertex pilosity, about 20–30 setae; scapes falling slightly short of, to slightly surpassing vertex corners, faintly clavate in the apical third or gradually thickening apically; pronotum with 3–10 dorsal erect setae; mesonotal profile flat; propodeal profile subquadrate; petiole straight- to slightly convex-sided, petiolar dorsum evenly convex; first tergite lacking pubescence; first tergite pilosity sparse (usually <10 macrosetae), straight, suberect, often deciduous (indicated only by macrosetal sockets in many specimens).

Head matte; mesonotum matte with only slightly smoother pronotal sides; gaster weakly shining.

Color mostly red with darker, brown appendages, and similarly dark lower lateral mesosoma, and posterior portions of tergites.

Discussion. Polyergus sanwaldi closely resembles longicornis , but has consistently shorter appendages ( Fig. 2 ) and more northern (and apparently allopatric) distribution.

Etymology. This species is named for Raymond Sanwald, who led to its discovery through his interest in Polyergus , and his willingness to host years of studies by Howard Topoff and his students on the Polyergus species resident at Ray’s Medford (Long Island) NY “Ant Ranch.”

Natural history. I have studied samples of this ant originating from Massachusetts to northwestern Indiana and southern North Dakota. All samples originated from localities with deep, sandy soil. It seems likely it could be found in intervening sandy soil locations, such as the Oak Openings of Ohio or black oak savannas of northern Illinois, Wisconsin and southern Minnesota.

Goodloe and Sanwald (1985) and Goodloe, Sanwald and Topoff (1987) studied this ant in their work on host specificity of “ lucidus . ” The host of this species is exclusively F. d o l o s a (reported as F. schaufussi ). These authors determined experimentally that mated gynes from colonies of sanwaldi were not accepted into groups of F. incerta workers, and likewise that gynes of lucidus were not accepted into groups of F. do l os a, while gynes introduced to groups of workers of the species of Formica in their home-nest most often were accepted. In the field, raids of the two species, again, were conducted only on the respective host species in the Polyergus home nest. Their papers were my first clue that lucidus , sensu lato might in fact be more than one species. The habitat of this species is sandy or sandy loam prairies and old fields, and sandy oak and pine savannas.

Distribution of studied specimens. INDIANA Porter Co. Westchester Township. Sec. 29. 8 -VII-1957, Sidney Hatfield #97 (FMNH); INDIANA Porter Co. Westchester Township Sec.100. 11 -VII-1957, Sidney Hatfield #100 (FMNH); MASSACHUSETTS, Norfolk Co. Blue Hills Reservation 5-IX-1919 GC&JN Wheeler (LACM, CASENT0172895); NEW JERSEY Ocean Co. Dwarf Pine Plains S.P. Cover. Unburned site E. of Tr. 539 5-12-86 #758 (MCZ); NEW JERSEY Ocean Co. East Dwarf Pine Plains. S.P.Cover. Burned (1983) Site W. of Rt. 539 5-13- 86 #770.; NEW YORK Suffolk Co. Medford. Summer 1986 R. Sanwald (several collections, JCTC); NEW YORK Suffolk Co. Medford. Lab. Colony coll. Summer 1986 L. Goodloe (JCTC); NEW YORK Suffolk Co. Medford. 17 May, 1987, JC Trager, leg. (several collections, JCTC); NORTH DAKOTA #83 T144N R65W, sec. 7 Stutsman Co. 1-VIII-1959, Delton D. Halverson (LACM).

Figures

FIGURE 2. Scatter plot comparing head length / scape length ratios of Polyergus longicornis and Polyergus sanwaldi.

FIGURES 42 – 44. Lateral, full face, and dorsal views of Polyergus sanwaldi worker CASENT 0281058. Photographs by Shannon Hartman from www. AntWeb. org.