Comprehensive DescriptionRead full entry
types Amer. Mus. Nat. Hist.; Mus. Comp. Zool. Harvard.
etymology L barbata HNS , bearded, alluding to the long, coarse hairs on the ventral head surface of the minor.
diagnosis A member of the " bicarinata HNS complex" of the larger pilifera HNS group, comprising agricola HNS , aurea HNS , barbata HNS , bicarinata HNS , centeotl HNS , cerebrosior HNS , defecta HNS , gilvescens HNS , macclendoni HNS , macrops HNS , marcidula HNS , paiute HNS , pinealis HNS , psammophila HNS , vinelandica HNS , xerophila HNS , yaqui HNS , and yucatana HNS ( barbata HNS is closest to psammophila HNS ), which complex is characterized by the large to very large, forward-set eyes of both castes; and, in the major, the occipital lobes lacking any sculpturing (except in aurea HNS ), the posterior half of the head capsule smooth and shiny; and the postpetiolar node seen from above oval, elliptical, or laterally angulate (cornulate in cerebrosior HNS ).
P. barbata HNS is distinguished by the absence of propodeal spines in both castes. Further: in the major, teeth absent on the hypostoma; humerus very prominently lobose in dorsal-oblique view; and spinose subpetiolar process seen in side view.
Minor: very long coarse hairs (psammophore?) line the ventral surface of the head; petiolar and postpetiolar nodes very low.
Measurements (mm) Major (Rancho Dos Palmas, California): HW 1.62, HL 1.72, SL 0.74, EL 0.26, PW 0.72.
Syntype minor: HW 0.44, HL 0.54, SL 0.52, EL 0.18, PW 0.30.
color Major: head brownish yellow, with occiput and area around midcenter line light brown; mesosoma, waist, and antennae brownish yellow; legs medium yellow. Minor: concolorous light yellowish brown.
Range Western Arizona, southern Nevada, and southeastern California (Creighton and Gregg 1955; G. C. and J. N. Wheeler 1973e, 1986g).
Biology According to Creighton and Gregg (1955), barbata HNS is a desert species, which prefers to nest in light, sandy soil, although it also lives in coarse, hard-packed sand along the edges of arroyos. The nest is surmounted by a low crater 5-10 cm in diameter, and it is sometimes also surrounded by a chaff ring, suggesting that barbata HNS is a harvester ant. Colonies excavated by Creighton comprised up to 11 majors and 73 minors, although this may be an underestimate of the real population size, since no nest queen was ever found. Similar nest structures were encountered in Deep Canyon, near Palm Springs, California, by G. C. and J. N. Wheeler (1973e).
figure Upper: major. CALIFORNIA: Rancho Dos Palmas, east of the Saltan Sea.
Lower: minor, syntype. (Type locality, origin of minor: Mojave Desert near Needles, San Bernadino Co.). Scale bars = 1 mm.