Many ants posses very obvious forms of surface sculpture. On the head of a P. anzensis worker, this consists of prominent ridges (rugae) that run lengthwise, and form whorls around the eyes. The spaces between the rugae (the interrugal spaces) are somewhat shiny, as can be seen in the image below. Another unusual feature of P. anzensis' surface sculpture is the pair of larger, carinate rugae that adorn the occipital corners of the head (indicated by arrows in the image below).

Other Pogonomyrmex species (and other ants) possess various types and degrees of surface sculpturing - the exact form differs from species to species, and is one of the many morphological characters used to identify and classify ants. These wrinkles and ridges undoubtedly lend a great deal of strength to the ants' armor-like integument (outer body covering).

[IMAGE: Pogonomyrmex anzensis worker self-grooming. This is an extreme crop (poor quality) included only to illustrate these small features] [scroll down for additional notes/references]

Pogonomyrmex anzensis - some surface sculpture features.

ADDITIONAL NOTES/REFERENCES:

·Cole, A.C. 1968. Pogonomyrmex Harvester Ants: A Study of the Genus in North America. Knoxville, University of Tennessee Press
·Harris, R.A. 1979. A Glossary of Surface Sculpture. California Department of Food and Agriculture, Division of Plant Industry, Laboratory Services/Entomology, No. 28
·Taber, S.W.,J.C. Cokendorfer & O.C. Franke.1987. Scanning Electron Microscopic Study of North American Pogonomyrmex (Hymenoptera:Formicidae). Proceedings of the Entomological Society of Washington. 89(3), 1987, pp. 512-526