Dorsal infraciliature

Description :

Dorsal infraciliature of the large nassulid ciliate Obertrumia aurea (Ehrenberg, 1833; Foissner 1987). Synonym of Nassula aurea. Obertrumia is distinguished by it's bipartite "hypostomial frange", linear arrays of ciliary tufts. A sigmoid ventrolateral frange runs anteriorly and to the left. The dorsal termination of this part is seen as a vertical arrangement of rectangular collections of kinetids (blue arrow). It terminates at the left end of the horizontal line of ciliary tufts on the dorsal surface (yellow arrow). The uniform longitudinal somatic kineties are well seen here. In vivo the cell appears brightly colored (orange, green or violet) due to multiple food vacuoles containing ingested cyanobacteria. Numerous small mucocysts give the cortex a roughly granular appearance. O. aurea feeds mainly on cyanobacteria. Silver carbonate stain (see Foissner, W.Europ. J. Protistol.27,313-330;1991). Collected from a freshwater pond near Idaho City, Idaho Septmeber 2004. Brightfield optics.