Guide to Identification of
Fresh Water Microorganisms

Protozoa - Heterotrophic only

 Name

Picture

Characteristic

Taxonomy

Flagellates
<.5mm

1. one or more flagella
2. colonial or free living

3. with or without lorica

Zoomastigophora
i.e choanoflagellates

Amoeba
.02 5 mm

1. pseudopodia
2. slow movement

3. engulfs food

Sacrodina
Order Amoebina
i.e. Amoeba proteus

Shelled Amoeba
.1-.4 mm

1. amoeba with a shell, usually sand grains
2. pseudopodia

3. slow movement

Sacrodina
Order Testacea

i.e  Arcella sp.

Heliozoans
.01-1 mm

1. spherical
2. radiating hair like pseudopods
3. no movement

Sacrodina
Order Heliozoea

Ciliates Peritrich
< .25 mm

1. cylindrical or bell shaped bodies
2. undulating cilia
3. some stalked
4. often colonial

5. attached to different substrate

Ciliophora
Order Peritrichida

i.e. Vorticella sp.

Ciliates Suctoria
<.7 mm

1. no cilia, sticky tentacles
2. some attached to other organisms (i.e. Suctoria)

Ciliophora
Order Eridogenida

i.e. Tokophyra sp.

Ciliates
Paramecium

.01 4mm

1. mostly free living forms
2. cell of fixed shape
3. movement by contraction and use of cilia

4. fixed mouth and anal pore

Ciliophora
Order Oliogohymenophorea

i.e. Paramecium sp

Ciliates
Stentor
.01 4 mm

1. large body
2. contractile

3. cilia on mouth end

Ciliophora
Orer Heterotrichea

i.e. Stentor sp

Ciliates
Coleps
.01-4mm

 

1. barrel-shaped
2. spinous projection at posterior end

3. cytosome apical

Ciliophora
Order Prostomatea

i.e. Coleps sp.

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