Amoeba "Naturalist" Page

This page is a series of links to the various protozoan amoeba that I have observed and sketched over the years. I observe protozoa similar to the way birdwatchers enjoy observing birds. The following Protozoa have thumbnail images and text observations: clicking them will take you to the scanned JPG images of the 4X6" card sketches.
Note: New species sightings after 3/2012 will be photographs.

The list is by no means complete. An excellent reference if you want information and images on more species is "How To Know the Protozoa" by Jahn.

These are the amoeba in alphabetical order:
Click on the thumbnail image or organism name to see full size image drawings.


Clear anterior margin with several extending pseudopodia. Some free living Acanthamoeba species have been recorded to cause human encephalitis. Humans swimming in summer ponds are infected through the nasal mucosa leading to infection in the brain. The organism also can cause eye infections after colonizing the solution that contact wearers soak their contacts in.
This sighting was from a puddle inoculated into a grass infusion solution.

Actinophrys sol:

Also called the "sun animalcule". Common among fresh water vegetation. Observed one "paralyze" a small ciliate and slowly envelope it.
Seen in a variety of fresh water samples: waterfall water incubated, duckweed filled ditch, sloughs, Kline pond, and the tannin frog pond at the Ridgefield wildlife refuge.
Here is a timelapse Youtube video of an Actinophrys undergoing asexual reproduction by binary fission:

Amoeba proteus:

Large size. Lobopodia have ridges. Single nucleus, pseudopods are granular. Entire organism can pass through any pseudopod. Pseudopods do not anastomose. This organism is not common in nature.
Here is a timelapse Youtube video of this amoeba.
Seen in Klineline algae sample several weeks old after adding hay infusion.

Arcella vulgaris:

Amoeba with a test (shell). Active hyaline pseudopods. The Jahn reference mentions unique technique for organism uprighting itself.

Ciliophrys infusionum:

Extremely fine radiating filopodia (almost invisible).
Similar to Actinophrys sol (sun animalcule) except for the test and finer filopodia.
3/85 old sample from duckweed ditch.

Difflugia species:

Shell (test) is made of minute "sand" particles. Internal symbiotic zoochlorellae give this organism a green hue.
Cylindrical exploratory pseudopods. Occasional smaller finger like projections.
Seen in Delta Park slough 5/84 and 7/84. also waterfall sample and a puddle.

Echinosphaerium arachnoideum:

Similar to E.eichhorni except no no distinct endoplasmic differentiation. Irregularly vacoulated.
7/86 Klineline algae. 10/87 Kline pond; old sample.

Echinosphaerium eichhorni:

Also known as Actinosphaerium eichhorni. Fresh water among vegetation and algae. On culture it was seen eating Stentors !
The YouTube video at the top of this page shows one capturing a Vorticella teletroch
5/84 ditch water. 10/85 Stream contaminated with cow manure. 4/2008 Vancouver Lake marsh.

Euglypha species:

Intricate shell (test). Filipodia dichotomously branched.
4/1989 dry inocula from a Bend area lake was rehydrated and incubated for 5 weeks. This species and Trinema predominated

Flabellula velata:

Broader than long. Broad clear layer of cytoplasm across the entire anterior end.
6/84 very old sample of pond water.


Like Echinosphaerium species but with a test (shell) made of microscopic "sand" grains. See video on YouTube of one capturing a small protozoan.
3/2012 Klineline lake

Nuclearia delicatula:
Changes shape for motility. Active algae eater. The gelatinous envelope may or may not be present.
Adhering bacteria mentioned in Kudo reference. In my sample I also noted associated tiny flagellates. Filopodea difficult to see, occasional branching even more difficult to detect.
Actinocoma species similar but with only one nuclei.
9/85 Klineline gliding algae. 6/86 aquarium. 10/86 Klineline algae again.

Pamphagus species:

Test (shell) hard to see as cell fills test completely. Long filipodia. Observed it ingesting diatoms, see card.
4/88 Ditch algae bloom

Pelomyxa palustris:

Moves by eruptive protoplasmic waves. No pseudopodia seen. Large at 400 microns. Note posterior spines.
4/84 stagnating sample from waterfall. 9/84 stagnating sample from Delta Lake.

Penardia species:

Amazing intricate branching and anastomosing pseudopods.
Green in cytoplasm due to ingested algae.
10/86 among Klineline algae.

Polychaos dubia:

This amoeba is similar to Amoeba, Metachaos and Chaos species, but this genus moves through several pseudopods simultaneously by forming an advancing web between the advancing pseudopods. See dashed lines on the card. The net effect is that the organism moves forward and also retains it's shape giving the appearance of gliding.
5/84 stagnating sample from waterfall. 4/86 Kline pond.

Pseudodifflugia gracilis:

Test is similar to Difflugia but the organism has filopodia instead of pseudopodia.
Pulls test along at about 1 body length per 10 minutes. Eats algae.
4/88 Several seen in ditch water algae bloom.

Striamoeba species:

Progresses with little change in shape. Moves about 1 micron per second. It does change shape when changing directions: becoming round before progressing in a new direction.
2/86 infusion culture. 5/18/1997 in Klineline dead algae during PSU protozoology course.

Thecamoeba species:

Observed this one eat a small nematode. It took a long time for the nematode to stop wiggling.
10/85 Puddle algae near Klineline. 11/91 in rain gutter wet leaves.

Trichamoeba limax:

Eruptive wave motility. Similar to Valkampfia limax but with posterior uroid with hair-like projections.
5/84 ditch water.

Trinema species:

Filipodia not branched.
4/1989 dry inocula from a Bend area lake was rehydrated and incubated for 5 weeks. This species and Euglypha predominated

Valkampfia limax:

Active progression by eruptive waves.
4/84 stagnant sample from waterfall. 6/84 very old sample of pond water. 3/89 Bend lake infusion.

possible Legendrea bellerophon:

5/84 Columbia River boat launch

This page is a series of links to the various ciliate protozoa that I have observed and sketched over the years. My original cards were made in the late 60's after obtaining a copy of "How To Know the Protozoa" by Jahn. Those cards are lost long ago but in the 80s I obtained a clinical quality microscope and started this nature hobby again. I observe protozoa similar to the way birdwatchers enjoy observing birds.

If you have any questions you can contact me by email at the Email us link at the top of the page

Created on ... March 23, 2003

Updated on ... March 04, 2012