Centropyxis aculeata
                This is a vent view of a sample of Centropyxis aculeata
                  from a municiple sludge. Three of its spine structures
                  can be seen 3, 4, and 6 o'clock positions in this image. The color of this specimen
                  is the result of an anaerobic environment with the iron
                  present in the cast converted in part to iron sulfide.
              
              
                Transmitted Oblique Illumination
                
Definition/Function:
                Centropyxis aculeata is a rhizopoda of the Order Testacida and Family Difflugiidae. It
                is a very common Thecamoebian.
                Significance in the Environment:
                In comparisons between the thecamoebian populations in freshwater lakes the presence of
                a higher proportion of Centopyxis aculeata may indicate
                a more brackish condition.
                Characteristic Features:
                Centropyxis aculeata is oval with 4-6 spines distal from the vent. It may be translucent
                to opaque, typically in shades of brown to black.
                Associated Particles:
                References:
                Jahn, T. L., HOW TO KNOW THE PROTOZOA, Wm. C. Brown Co. Publ., p. 127, 1949.
                
                Scott, DAVID B., FRANCO S. Medioli, and Charles T. Schafer, MONITORING IN COASTAL
                ENVIRONMENTS USING FORAMINIFERA AND THECAMOEBIAN INDICATORS,
                Cambridge University Press, p. 112, 2001.