Scuticociliatia

Left side view.  Key to Schewiakoff's abbreviations:  b -- Sensory bristle cv -- Contractile vacuole ek -- Ectoplasm l.Pr -- Left edge of peristome m -- Undulating membrane N -- Macronucleus ncl -- Micronucleus nv -- Food vacuole 

Ventral view.  Key to Schewiakoff's abbreviations:  b -- Sensory bristle cv -- Contractile vacuole l.Pr -- Left edge of peristome m -- Undulating membrane o -- Mouth r.Pr -- Right edge of peristome

Synononym: Cyclidium glaucoma var. elongatum (Schewiakoff, 1889).  Key to Schewiakoff's abbreviations:  a -- Anus b -- Sensory bristle cv -- Contractile vacuole ek -- Ectoplasm m -- Unduating membrane N -- Macronucleus ncl -- Micronucleus  

Paracyclidium (para-sigh-clid-ee-um), one of the cylidiid scuticociliates. Scuticociliates have a curved undulating membrane associated with the mouth, and within the family, this genus is distinguished because the kineties are broken in the centre of the cell. This allows us to see the epibiotic rod-shaped bacteria. Ciliates with external bacteria are often encountered in an anoxic sites suggesting that the symbiosis is linked to respiratory metabolism. Phase contrast.

Paracyclidium (para-sigh-clid-ee-um), one of the cylidiid scuticociliates. Scuticociliates have a curved undulating membrane associated with the mouth, and within the family, this genus is distinguished because the kineties are broken in the centre of the cell. This cell is included because of the large numbers of ectosymbiotic bacteria that are attached to the cell surface. Phase contrast.

Paracyclidium (para-sigh-clid-ee-um) is a small scuticociliate, a group which usually has a well developed veil of cilia projecting around the mouth region (flopped , and these can be see to one side of each cell. It eats bacteria. May occur in organically enriched habitats with large numbers of bacteria. Rows of cilia (kineties) are interrupted in the central region of the body. Cyclidium is similar, but the kineties are unbroken. Long caudal cilium. Phase contrast.

Ventral view of Dexiotrichides centralis (STOKES, 1886) , a sapropelic hymenostome ciliate. D. centralis is the only freshwater species of the genus. The cell is reniform and laterally compressed. The relatively large cytostome is located in the center of the body (seen well here). There are three adoral membranelles. There is an undulating membrane on the right margin of the cytostome. The somatic kineties are longitudinal. On the right surface there is an oblique row of longer cilia slanting posteriorly from the cytostome (seen here). There is a long caudal cilium. The contractile vacuole is terminal. The macronucleus is spherical . D. centralis is a facultative anaerobe. Easily confused with members of the similar genus, Dexiotricha. Collected from the bottom material in a freshwater aquaculture tub near Boise, Idaho in October 2003. DIC. DIC  Song et al have described a marine species, Dexiotrichides pangi [Song et al . Dexiotrichides pangi n. sp. (Protozoa, Ciliophora, Scuticociliatia), a New Marine Ciliate from the North China Sea. J.Eukaryot. Microbiol., 50(2), pp. 114-122,2003.]

Left side of Dexiotrichides centralis (STOKES, 1886), a sapropelic scuticociliate. D. centralis is the only freshwater species of this genus. The cell is reniform and laterally compressed. The relatively large cytostome is located in the center of the body. There are three adoral membranelles. There is an undulating membrane on the right margin of the cytostome. The somatic kineties are longitudinal. On the right surface (not seen in this image) there is an oblique row of longer cilia slanting posteriorly from the cytostome. There is a long caudal cilium (seen here). The contractile vacuole is terminal. The spherical macronucleus is found in the anterior half. D. centralis is a facultative anaerobe. Easily confused with members of the similar genus, Dexiotricha. Collected from the bottom material in a freshwater aquaculture tub near Boise, Idaho in October 2003.DIC Song et al have described a marine species, Dexiotrichides pangi [Song et al . Dexiotrichides pangi n. sp. (Protozoa, Ciliophora, Scuticociliatia), a New Marine Ciliate from the North China Sea. J.Eukaryot. Microbiol., 50(2), pp. 114-122,2003.]

Dexiotrichides centralis (STOKES, 1886). Stained by the silver carbonate technique (Foissner,W. Europ. J. Protistol.27:313-330;1991).Brightfield.

Lateral view (optical section) of Dexiotrichides centralis (STOKES, 1886). The blue arrowhead indicates the oral aperture. Densley stained endosymbiotic bacteria are seen in the cytoplasm. Stained by the silver carbonate technique (Foissner,W. Europ. J. Protistol.27:313-330;1991).Brightfield.

Right ventrolateral view (optical section) of the oral infraciliature of Dexiotrichides centralis (STOKES, 1886). The blue arrowhead indicates the oral aperture. Densley stained endosymbiotic bacteria are seen in the cytoplasm. Stained by the silver carbonate technique (Foissner,W. Europ. J. Protistol.27:313-330;1991).Brightfield.

Right ventrolateral view (optical section) of the oral infraciliature of Dexiotrichides centralis (STOKES, 1886). The blue, green and light blue arrowheads indicate the kinetosomes of the first (M1), second (M2) and third (M3) adoral membranelles respectively. The pink arrowhead indicates the undulating membrane on the right margin of the cytostome. The yellow arrowhead indicates the rhomboidal scutica, unciliated kinetosomes of the buccal anlage. Densley stained endosymbiotic bacteria are seen in the cytoplasm (white arrowhead). Stained by the silver carbonate technique (Foissner,W. Europ. J. Protistol.27:313-330;1991).Brightfield.

Right side view.  Key to Schewiakoff's abbreviations:  a -- Anus b -- Sensory bristle cv -- Contractile vacuole ek -- Ectoplasm m -- Undulating membrane N -- Macronucleus ncl - Micronucleus