red and black form: collected from the Chiricahua Mtns, Cochise Co.
Wilson, E. O.:
Pheidole hyatti Emery 1895d: 295. Syn.: Pheidole vaslitii Pergande 1896: 883, synonymy by Ward 2000: 85; Pheidole hyatti var. ecitonodora Wheeler 1908h: 463, synonymy by Creighton 1950a: 180; Pheidole hyatti subsp. solitanea Wheeler 1915b: 409, n. syn.
diagnosis Similar to ariel , desertorum , and vistana , differing from these and other members of the fallax group as follows. Reddish yellow (major) or light reddish brown (minor); antennal scape moderately long, flattened basally, approaching the occipital border to within about half its own maximum width; pilosity over all the body dorsum dense, very long, and erect to suberect; in dorsal-oblique view, pronotum faintly bilobous and humerus rounded; an extensive rugoreticulum stretches from in front of and mesad to each eye to the circular carinulae of the antennal fossa; dorsum of head and sides of mesosoma and waist foveolate and opaque.
Minor: occiput broad, lacking nuchal collar; pilosity of body dorsum dense, very long, and erect to suberect; propodeal spines small but well-formed; mesopleuron and sides of propodeum and waist foveolate and opaque; rest of body smooth and shiny.
According to Stefan Cover (personal communication), hyatti is likely a complex of sibling species.
measurements (mm) Syntype major: HW 1.32, HL 1.34, SL 0.98, EL 0.22, PW 0.64.
Minor (Huachuca Mts., Arizona): HW 0.60, HL 0.70, SL 0.86, EL 0.14, PW 0.40.
Color Major and minor: concolorous light reddish yellow to medium or dark brown.
range P. hyatti is scarce in Colorado, where Gregg (1963) found it at only two localities. It also occurs, often locally abundant, from central Texas to southern California and northern Mexico.
Biology Gregg (1963) encountered the Colorado colonies in warm pockets of short grass prairie at 1700 m, and Cole (1953g) found it in New Mexico in pinyon-juniper woodland at 2000 m. Numerous series i have examined from the southwestern United States, many collected and annotated by Stefan Cover, are from nests in open soil and beneath stones and cow pats in a wide range of xeric habitats, from desert grassland to open juniper-oak woodland. Similar habitat records have been published for Utah by Ingham (1959) and Allred (1982) and for Nevada by G. C. and J. N. Wheeler (1986g). Winged queens have been found in nests from 4 July to 7 August. Droual has described the remarkably efficient maneuvers of nest defense and evacuation by hyatti colonies under attack by army ants ( Neivamyrmex nigrescens ). Droual and Topoff (1981) have shown that emigrations to new sites occur at a high frequency even under apparently stable environmental conditions. The species needs closer study to investigate the possibility that it is a complex of sibling species, in which case the biological data will have to be sorted out for accuracy.
Figure Upper: syntype, major. CALIFORNIA: San Jacinto. Lower: minor. ARIZONA: Huachuca Mts. (compared with minor syntype). Scale bars = 1 mm.
Ward, P. S., 2005: