AN ANALYSIS OF GEOGRAPHIC VARIATION IN THE 
POGONOMYRMEX OCCIDENTALIS COMPLEX 
(HYMENOPTERA: FORMICIDAE) 1 
By Steven O. Shattuck 
Department of Entomology, 
University of Kansas, 
Lawrence, Kansas 66045 
Introduction 
While examining samples of Pogonomyrmex from southeastern 
Oregon, I encountered difficulty in segragating the two species 
reported as occurring in the area, P. owyheei Cole and P. salinus 
Olsen (Cole, 1968). Analysis of material from Oregon, Nevada and 
Utah suggested that the taxonomy of these two forms needed reeval- 
uation. Smith (1953) considered them a single species, but this view 
was subsequently rejected by Cole (1968). 
Cole (1963, 1968) described the occidentalis complex as com- 
posed of P. owyheei and salinus, together with P. anzensis Cole, 
brevispinosus Cole, occidentalis (Cresson), subdentatus Mayr and 
subnitidus Emery. MacKay (1980) described P. montanus from 
southern California, bringing the complex to a total of 8 species. 
Within the occidentalis complex, the species P. owyheei, salinus, 
occidentalis, subdentatus and montanus form a distinct, plausibly 
monophyletic group, united by the cephalic sculpturing, configura- 
tion of the antennal scape base, and thoracic sculpturing. This 
group is referred to here as the occidentalis subcomplex. Because 
they do not possess this combination of characters, and because 
monophyly of the occidentalis complex as a whole is uncertain, P. 
anzensis, brevispinosus and subnitidus were excluded from this 
group and the present study. 
•Extracted from a thesis submitted to the University of Kansas in partial fulfillment 
of the degree of Master of Arts. Present address: Department of Entomology, Uni- 
versity of California, Davis, CA 95616. Contribution number 1953 from the Depart- 
ment of Entomology, University of Kansas. 
* Manuscript received by the editor February 8, 1987. 
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