Infraciliature of Colpoda maupasi (ENRIQUES,1908).Collected from a non-flooded Petri dish culture of soil from a park lawn in Boise, Idaho.March 2008.Stained by the Protargol technique [Wilbert modification] (see Foissner, W. Europ. J. Protistol., 27:313-330;1991).Brightfield. This image was taken by William Bourland. He now uses a Zeiss Axioskop 2 with Spot Insight and Spot Flex CCD cameras (Diagnostic Instruments). Image copyright: William Bourland, image used under license to MBL (micro*scope).
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From the collection
Freshwater and Terrestrial Microbes of Idaho (USA) and Elsewhere
|Description of Colpoda maupasi: Colpodid ciliate, 35-80 x 20-50 microns, usually about 60 x 30 microns. Appearance from the side is reniform, preoral portion remarkably short (1/4-1/3 of body length), usually slightly ventrally inclined. Well-nourished specimens almost globular postorally, causing tapered preoral portion. Flattened slightly to 2:1, in ventral and dorsal aspect pyriform to moderately broadly wedge-shaped; no postoral sack. Macronucleus approximately 10 microns in vivo, in some populations globular, in others slightly to distinctly ellipsoid, usually near centre of cell. Data on nucleoli disparate, coarse grained, plate-like to reticulate, ramified, small and large, irregularly?formed. Shape of macronucleus also varies within the same population from globular to ellipsoid and is, occasionally, even distinctly reniform. Micronucleus calotte-shaped, about 2 x 1 microns, attached to macronucleus, strongly Feulgen positive. Contractile vacuole at posterior end, during diastole with small collecting vesicles, single excretory pore in centre of posterior pole. Cortex flexible, coarse, often distinctly furrowed by somatic kineties to produce above mentioned lattice-effect in normally fed and undernourished specimens. Extrusomes about 1 microns in diameter, within somatic kineties. Cytoplasm with few to many rod-shaped, yellowish crystals, especially in vicinity of contractile vacuole. Feeds on bacteria. Food vacuoles compact, often rendering cells opaque. Movement moderately rapid, usually creeps quickly among soil particles, frequently remaining immobile during feeding whereby cilia are spread, presumably with thigmotactic effect. Cilia approximately 7 microns long, particularly closely spaced near keel, on right side usually paired, on left anterior cilium often lacking in postoral dikinetids. Number of somatic kineties, which course distinctly spirally, conspicuously constant: in many populations on average 15-18, with a total variability of 14-20. Keel with 4-7, usually 5 distinct notches. 3-4 postoral kineties. Occasionally a small kinety fragment consisting of 3-4 dikinetids on anterior vestibular margin, possibly produced, as in C. inflata, by interruption of kinety 1. In C. maupasi it is, however, not connected to a postoral kinety by a silverline, indicating that it could belong to the rearmost left lateral kinety. Oral apparatus in anterior third. Vestibulum remarkably small in relation to overall size, oral polykinetids protrude. Left polykinetid elliptical, occasionally slightly wedge-shaped or rectangular, distinctly broader than in other members of group, extends horizontally on bottom of vestibulum, its cilia project only slightly beyond body margin. Colpoda maupasi is readily recognizable by this distinctive shape and size of the left polykinetid. The number of kineties it consists of is also fairly constant, viz. 8-12 with an average of 9-10. Right polykinetid composed of about 7 curved kineties, strongly resembling other small Colpoda species, forms an angle of approximately 60 degrees with left polykinetid. No vestibular kineties. |