Polyergus vinosus, 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 : 520-521

Polyergus vinosus new species

Figures 18, 19, 20

Holotype worker USA, CALIFORNIA Millard Canyon, San Gabriel Mts. [LACM.]

Paratypes 2 gynes, 1 male, 4 workers (One of the latter possibly an ergatoid.) [LACM]

Holotype HL 1.39, HW 1.34, SL 1.34, ½ VeM 0, ½ PnM 3, WL 2.16, GL 1.93, HFL 1.72, CI 96, SI 100, HFI 128, FSI 128, LI 3.55, TL 5.48.

Paratype worker measurements (N=4) HL 1.39–1.64 (1.51), HW 1.34–1.60 (1.46), SL 1.32–1.40 (1.37), ½ VeM 0, ½ PnM 3–6 (3.80), WL 2.16–2.40 (2.27), GL 1.64–2.44 (2.02), HFL 1.72–1.95 (1.83), CI 95–98 (97), SI 88–100 (94), HFI 122–128 (125), FSI 128–139 (134), LI 3.55–4.04 (3.78), TL 5.48–6.48 (5.81).

Measurements (N=36) HL 1.23–1.67 (1.43), HW 1.20–1.60 (1.40), SL 1.14–1.41 (1.27), ½ VeM 0–2 (0.11), ½ PnM 0–7 (3.43), WL 1.93–2.48 (2.18), GL 1.64–2.82 (2.14), HFL 1.55–2.00 (1.73), CI 95–103 (98), SI 80–100 (91), HFI 113–133 (124), FSI 128–142 (136), LI 3.23–4.15 (3.60), TL 4.26–6.97 (5.69).

Worker description. Head truncate-ovate, its length usually slightly greater than breadth; scapes long for the breviceps species group (SI usually 85–95, never <80), nearly reaching or even surpassing vertex corners, weakly clavate or gradually thickening in the apical third; pronotum with 0–6 (less often, up to 12, especially Santa Cruz Island population) dorsal macrosetae; mesonotum with profile weakly convex for most of its length, notably convex and “bulging” in the largest workers; propodeum subquadrate with a rounded angle; petiole sides rounded and converging dorsad, petiolar dorsum flat or even shallowly concave; first tergite densely pubescent; first tergite pilosity a relatively sparse 6–20 flexuous, mid-anterodorsal, suberect macrosetae and sometimes a few widely spaced ones in the posterior tergal half.

Head weakly shining; mesonotum weakly shining beneath fine gray pubescence; gaster weakly shining beneath fine gray pubescence.

Color mostly orange-red to wine red with scarcely any infuscation of gaster or appendages.

The most significant variation in this species is the greater pronotal pilosity of the Santa Cruz Island population, with ½ PnM 6–12, contrasting with 1–4 (rarely 5 or 6) on the mainland. Workers of Baja California are paler tan-orange in color (as in Fig. 6 , possibly faded in preservation), and have a more rounded propodeal profile.

Etymology. “ Vinosus ” is Latin for red-wine-colored. Somewhat ironically, much of its habitat may be threatened by the conversion of its southern California oak woodland habitat to vineyards.

Natural history. This species is endemic to the Californian vegetation zone of southern CA and northern Baja California, Mexico, and is also found on Santa Cruz Island, CA. Polyergus vinosus is a species of mature chaparral, coast live oak woodland and savanna, rocky wooded canyons and oak-gray pine woodlands of the southern California coast hills. As far as known, its exclusive host species is F. moki , and the nests have the host species’ usual cryptic placement among rocks, often near streams or along wet-weather drainages, and sometimes with a lightly thatched superstructure. Only a few raids have been observed, but from unpublished observations by Les Greenberg (U. C. Riverside, pers. comm.) and Geoff Trager (then a student at UC Santa Barbara, pers. comm.), we know that the raids take place in early to mid summer, in the latter half of the afternoon. The raiding season may begin and end earlier than that of species from colder, summer-rainy climates.

Distribution of studied specimens. CALIFORNIA Los Angeles Co. Tanbark Flats. San Gabriel Mts. VI-21- 1956 GI Stage, coll. (LACM); CALIFORNIA Los Angeles Co. San Gabriel Mts. Millard Canyon. Aug. 1953 R.H. Crandall (also 7-16-1955 R.H. Crandall, LACM); CALIFORNIA San Bernardino Co. Lake Arrowhead. 30-VI-00 L. LaPierre (JCTC); CALIFORNIA Monterey Co. Limekiln Cr. T215R4E Sec. 34 SW 1070m 11/Feb/1984 J Longino (JTLC); CALIFORNIA San Diego Co. Mr. Laguna SOSU Observatory 9 June 72 JNH 78r J.H. Hunt (JCTC); CALIFORNIA San Diego Co. Laguna Mtn. 1342 m. under rock, pine meadow 26-v-2010 L. Davis (JCTC); CALIFORNIA Santa Barbara Co. Figueroa Mtn. under board, open pine woodland. April, 1979 JCT (JCTC); CALIFORNIA Santa Barbara Co. T4NR25W Sec. 16 1500’ Chaparral #303 19/May/1985 J Longino (JTLC); CALIFORNIA Santa Barbara Co. Santa Cruz Island 0.5 km W Station 24 June 1984 S. Dinh & J. Nelson (LACM); CALIFORNIA Santa Barbara Co. Santa Cruz Isl. Forager Riparian woodland 23 June 2010 L Greenberg (JCTC); MEXICO, BAJA CALIFORNIA Sierra Juarez 15.8 m. S La Rumorosa 32°19.1’N 115°59.5’W 4900’ 25- III-2001 #2310 RA Johnson (RAJC).

Figures

FIGURES 18 – 20. Lateral, full face, and dorsal views of Polyergus vinosus worker CASENT 0281078. Photographs by Shannon Hartman from www. AntWeb. org.

FIGURES 6 – 8. Lateral, full face, and dorsal views of Polyergus breviceps worker Polyergus breviceps CASENT 0281065. Photographs by Shannon Hartman from www. AntWeb. org.