Polyergus topoffi, 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 : 519-520

Polyergus topoffi new species

Figures 15, 16, 17

Polyergus rufescens subsp. breviceps var. montezuma Wheeler 1914: 56 . Unavailable name; following material referred here: MEXICO, HIDALGO Pachuca [MCZ; 1 gyne, 3 workers, and host Formica ; red syntype label 9221] (examined, misspelled as “montezumia” on handwritten accompanying label); [USNM, 59726] (not examined; misspelled as “montezumia” in USNM type database).

Holotype worker: USA, ARIZONA, Cochise Co., Portal. Topoff property, N31° 54.578 W 109°0 8.909 CWT068 1472 m. Mesquite-Acacia thicket. JC Trager & CW Torres (MCZ)

Paratype workers: Same data as holotype [MCZ, CAS, LACM]

Holotype [ARIZONA, Cochise Co., as above] HL 1.62, HW 1.56, SL 1.22, ½ VeM 1, ½ PnM 9, WL 2.42, GL 2.40, HFL 1.80, CI 96, SI 78, HFI 115, FSI 148, LI 4.04, TL 6.44.

Paratypes (N=5) [ARIZONA, Cochise Co., as above] HL 1.56–1.64 (1.60), HW 1.52–1.60 (1.54), SL 1.20– 1.24 (1.22), ½ VeM 0–1 (0.55),, ½ PnM 6–9 (7.20), WL 2.32–2.42 (2.39), GL 2.16–2.40 (2.24), HFL 1.72–1.80 (1.76), CI 95–98 (97), SI 75–82 (79), HFI 111–117 (1.14), FSI 139–148 (144), LI 3.88–4.04 (3.98), TL 6.12–6.44 (6.22).

montezuma material (N=3) [MCZ] HL 1.48–1.60 (1.53), HW 1.50–1.53 (1.50), SL 1.20 (all 3), ½ VeM 0 (all 3),, ½ PnM 12–15 (13.67), WL 2.36 (all 3), GL 2.16–2.24 (2.20), HFL 1.64–1.72 (1.68), CI 96–100 (98), SI 78–81 (80), HFI 111–112 (1.12), FSI 137–143 (140), LI 3.84–3.9 (3.89), TL 6.08–6.12 (6.09).

Measurements, exclusive of montezuma syntypes (N=31)) HL 1.48–1.68 (1.60), HW 1.40–1.64 (1.53), SL 1.16–1.28 (1.23), ½ VeM 0–1 (0.23), ½ PnM 4–9 (6.87), WL 2.16–2.52 (2.37), GL 1.84–2.56 (2.20), HFL 1.68– 1.88 (1.77), CI 93–100 (96), SI 75–86 (80), HFI 108–121 (116), FSI 139–155 (145), LI 3.68–4.20 (3.97), TL 5.54– 6.64 (6.16).

Worker description. Superficially rather similar to mexicanus , but slightly more gracile, and nearly restricted to a Mexican distribution. Head nearly rectangular or quadrate, straight-sided anterior to eyes, with vertex corners rounded, HL usually a bit greater than HW; with vertex pilosity lacking or up to 2 setae; scapes not reaching vertex corners by about 1.5 maximum scape widths, notably clavate in the apical third; pronotum with 8–22 dorsal erect setae (but see

Discussion. of montezuma “ types ”, below); mesonotum with profile flat or only slightly convex for most of its length, with a short posterior declivity; propodeum evenly rounded with dorsal and declivitous faces, especially in smaller workers, usually at>90o angle; petiole straight-sided above spiracles, sides parallel or only slightly converging dorsad, flowing seamlessly into the semicircular petiolar dorsum; first tergite densely pubescent, pubescence very fine; first tergite pilosity evenly distributed or slightly denser anteriad, some setae flexuous near front of tergite, but most weakly flexuous or straight, suberect.

Head matte to weakly shining; mesonotum matte to weakly shining, with scant pubescence; gaster matte to weakly shining beneath pubescence, shinier on sides.

Color mostly tannish-red with infuscation of posterior portions of tergites and slightly darker legs. Mesosomal pilosity usually notably darker than body color, gaster pilosity more reddish; pubescence short and yellowish gray. Only minor individual variation was detected among the Arizona specimens studied, and the Mexican montezuma differed only in somewhat more abundant pilosity, but fit perfectly in the middle of the measurement cloud of other specimens measured.

Discussion. Of all the Nearctic species, topoffi is the one that most resembles Palearctic rufescens in sculpture, pilosity, head shape and appendage length. Where it overlaps with mexicanus in distribution, it is distinguished by a less shiny appearance and somewhat more tannish tinge to the base red color, longer scapes and legs, occurrence at lower elevations, and parasitism of different hosts. The scapes are longer than all other breviceps group species except vinosus . Wheeler’s unavailable variety montezuma, collected near Pachuca, Hidalgo, Mexico by Mann, belongs in this species, as it fits neatly within middle the range of metrics for Arizona topoffi (except with somewhat more abundant pilosity), and also comes from a subxeric, semi-open habitat. The three worker specimens of montezuma are more pilose than most Arizona specimens, with 22–26 macrosetae on the pronotum, and the three specimens each possess a few erect macrosetae lower on the sides of the pronotum. The montezuma sample is associated with the host species F. subcyanea .

Etymology. I name this for Howard Topoff, who with his students has contributed so much to the modern literature on Polyergus , and in particular on this species. Howard also has a magnificent colony of this Polyergus near his house outside Portal AZ from which holotype specimen and paratypes were collected.

Natural history. Polyergus topoffi is relatively well-studied. Studies of a population in the vicinity of Portal, AZ, and at the Southwest Biological Research Station, just 5 miles to the west, make this among the best studied of North American species. Colony foundation, sexual behavior, scouting and raiding of this species are documented in numerous publications by Howard Topoff and his students, under the name Polyergus breviceps (Topoff 1982, 1985, Topoff et al. 1984, 1985a, 1985b, 1988a, 1988b, 1989, Topoff and Greenberg 1988, Topoff 1990, Topoff and Mendez 1990, Topoff and Zimmerli 1993, Zimmerli and Topoff 1994), and even in National Geographic Society videos made with these authors’ cooperation, and at this writing, still occasionally aired on television nature programs. In the Chiricahua Mts. of AZ, the habitat of topoffi ranges from riparian desert scrub at 1450 m, to the ecotone of oak-juniper and conifer forest around 1900 m (and higher, in Mexico). It raids after the heat of the day, typically between 17:00 hr and dusk, robbing pupae from the host nests with little resistance and no mortality of the host workers, these known otherwise for their aggressive physical and chemical nest defense. Specimens of Wheeler’s var. montezuma fit nicely, in metrics, color and surface texture, in the morphological concept of this species. Thus, subtropical, Madrean scrublands and oak woodlands of the Mexican highlands are another habitat of this ant.

Distribution of studied specimens. ARIZONA Cochise Co. Chiricahua Mtns. 2.5km 292° Portal 31°55.92’N 10910.67’W ocotillo-opuntia rocky slope 1600m 4-14-VIII-2005 JT Longino (JTLC); ARIZONA Cochise Co. Chiricahua Mts. Cave Cr. Canyon IX-10-1971 (LACM); ARIZONA Cochise Co. Chiricahua Mts. Cave Creek Canyon Idlewilde Cmpgr. Elev. 4950’ #1466 8/4/1988; ARIZONA Cochise Co. S.W.R.S. 1995 Savolainen (1) 75/ 95; ARIZONA Cochise Co. Chiricahua Mts. Piney Canyon 5700’ Elev. 31°58.1’N 109°19.2’W 3.VIII.1991 #11 RA Johnson (RAJC); ARIZONA Cochise Co. Chiricahua Mts. SW Research Sta. 31°53.0’N 109°12.3’W 5400’ Elev. 9.VII.1993 #249 RA Johnson (RAJC); ARIZONA Cochise Co. Southwest Rsch. Section. 7-August-1986 H. Topoff P3, P5 (JCTC); SPCover (MCZ); ARIZONA Cochise Co. Chiricahua Mts. SWRS 5 m. W Portal Oak-Pine- Juniper Forest S of Station Elev. 5500’ SPCover #1472 (MCZ); ARIZONA Cochise Co. Chiricahua Mts. 6 m. W Portal 21-29 July and (?) Aug. 1983 M. Pagani; ARIZONA Cochise Co. Portal July 3, 1956 #370 AC Cole (LACM); ARIZONA Cochise Co. Wilcox. Cochise Stronghold July 30,1954 #155,124,155 AC Cole (LACM); ARIZONA Gila Co. Jones Water Camp 14 July 1986 0 0 4 GC Snelling (JCTC); ARIZONA Cochise Co. Coronado NF Cave Creek Ranch 31.90300-109.13495± 5m 1491m 31.VIII.2011 Zach Lieberman (JCTC); ARIZONA Cochise Co. Chiricahua Mtns. 9.3km W Portal 1900m 31.89956-109.23863± 200m oak-pine-juniper woodland 10-VII-2011 Zach Lieberman (JCTC); ARIZONA Cochise Co. Chiricahua Mtns. 10.5km W Portal E Turkey Creek 31.90882-109.25211± 200m 1960m pine-oak forest/Douglas fir 10.VIII.2011 Zach Lieberman (JCTC); ARIZONA Gila Co. Mazatzal Mtns. Pigeon Springs 33°42.5’N 111°20.1’W 5600’ Elev. #112 22.v.1993 RA Johnson (RAJC); ARIZONA Santa Cruz Co. Patagonia Mts. 2000 Savolainen 12/00 (JCTC); ARIZONA Santa Cruz Co. Hershaw Creek 31°29.5’N 110°41.2’W 4550‘ Elev. #2207 26.VIII.1999 RA Johnson (RAJC); MEXICO. HIDALGO Pachuca. W. M. Mann.

Figures

FIGURES 15 – 17. Lateral, full face, and dorsal views of Polyergus topoffi worker CASENT 0281077. Photographs by Shannon Hartman from www. AntWeb. org.