Psammonobiotus communis
Golemansky, 1967
Common Name:
A testate amoeba
Synonyms and Other Names:
Identification:
Amoebas in the family Psammonobiotidae have bilaterally symmetric tests (shells) of organic material covered in haphazardly arranged quartz shards. Pseudopods protrude through an opening at one end of the test surrounded by a flared flat collar (Golemansky 1974; Nicholls and MacIsaac 2004; Nicholls 2005). This species displays an oval or circular aboral region (Nicholls and MacIsaac 2004). In P. communis, the angle at which the test and collar join is =5° (Nicholls 2005).
Size:
In the Great Lakes this species averages 34 µm in length, 19 µm width and 15 µm height, with a collar diameter of 15–20 µm; however, specimens from around the world vary in length from 23–52 µm
Native Range:
P. communis is probably native to the Ponto-Caspian region (Black Sea, Caspian Sea, and Aral Sea basins), but it has been found in every ocean basin of the world (Nicholls and MacIsaac 2004) as well as freshwater Lake Leman in Switzerland (Golemansky and Todorov 2009). Also reported from the Chilean Antarctic (Golemansky 2016). Considered to have a cosmopolitan distribution (Golemansky and Todorov 2005).
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This map only depicts Great Lakes introductions.
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Great Lakes Nonindigenous Occurrences:
P. communis was recorded in Lake Huron in 2001 and in Lake Superior, Lake Erie and Lake Ontario in 2002 (Nicholls and MacIsaac 2004).
Ecology:
Habitat: Psammonobionts generally occur where interstitial water movement and oxygen supply are adequate (e.g., in beach sand). They attach to sand grains by way of the flat collar that is part of the test. P. communis occurs in different regions throughout the world at sand depths ranging from 10–105 cm and at distances of 0–35 m from the shoreline (Laminger 1973; Golemansky 1979; Golemanksy 1994). It is primarily a marine-brackish water species, although it tolerates salinities of 0–37‰ (Chardez 1971; Nicholls and MacIsaac 2004). Psammonobiotus spp. have also been reported from river plankton (Kiss et al. 2009), though rare and possibly representing animals displaced from normal habitat. Food Web: The pseudopods protrude from the oral opening of the test for locomotion and feeding. Testate amoebas feed on bacteria, small algae, fungi and particulate organic matter. Testate amoebae can be preyed on by nematodes and other worms, mites and other microinvertebrates. (Todorov and Bankov 2019)
Life History: Life history of this species has not been studied specifically. Testate amoebae generally reproduce asexually by simple division (binary fission). Daughter cells quickly construct their own test rather than inheriting half the parent test. Some testate amoeba have also been observed to reproduce sexually, but that has not been observed for this genus. Testate amoebae can produce resistant cysts against unfavorable environmental conditions. Cysts are formed within the shell with an additional thick membrane and reduced cell volume. Testate amoebae often seal the shell aperture prior to encysting (Todorov and Bankov 2019).
Great Lakes Means of Introduction:
The most probable vector of introduction to the Great Lakes is ship ballast (Nicholls and MacIsaac 2004). This species is widespread in the Baltic Sea (Golemansky 1998) which was a common source of ballast water entering the Great Lakes.
Great Lakes Status:
Widespread, overwintering and reproducing in Lakes Superior, Huron, Erie and Ontario. It should be noted that Lake Michigan has not yet been surveyed for this organism (Nicholls and MacIsaac 2004).
Great Lakes Impacts:
Summary of species impacts derived from literature review. Click on an icon to find out more...
Current research on the environmental impact of Psammonobiotus communis in the Great Lakes is inadequate to support proper assessment.
Compared to abundance in marine beaches, the density of P. communis in the Great Lakes has been relatively low (Nicholls and MacIsaac 2004). While the impacts of P. communis in the Great Lakes have not yet been studied, testate amoebae tend to prey upon and modify microbial populations, accelerate nutrient cycling, and be consumed by other organisms (e.g., Lousier and Parkinson 1984, Schönborn 1992). Furthermore, selective grazing by testate amoebae may influence microbial community taxonomic composition and metabolic activity (Bonkowski 2004, Sherr et al. 1992).
There is little or no evidence to support that Psammonobiotus communis has significant socio-economic impacts in the Great Lakes.
There is little or no evidence to support that Psammonobiotus communis has significant beneficial effects in the Great Lakes. In studies outside the Great Lakes, testate amoebae have been used as indicators of ecosystem condition and function (e.g., Fournier et al. 2012).
Management:
Regulations (pertaining to the Great Lakes)
| Jurisdiction | Regulation | Law | Description | Date Effective |
| Illinois | Other | 515 ILCS 5/20-90 | This species is not on the Illinois Aquatic Life Approved Species List and if it is not otherwise native to Illinois it is illegal to be imported or possessed alive without a permit. | 7/9/2015 |
Note: Check federal, state/provincial, and local regulations for the most up-to-date information.
Control
There are no known control methods for this species.
Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.
Remarks:
Given the lack of research effort devoted to testate amoebae to date, this species may have been present in the Great Lakes for many decades prior to its discovery. However, Nicholls and MacIsaac (2004) also remark that the Psammanobiotus species, given their current distribution pattern, may be relatively recent arrivals to the Great Lakes.
References
(click for full reference list)
Author:
Kipp, R.M., A.K.Bogdanoff, and A. Fusaro.
Contributing Agencies:
Revision Date:
9/3/2025
Citation for this information:
Kipp, R.M., A.K.Bogdanoff, and A. Fusaro., 2025, Psammonobiotus communis Golemansky, 1967: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI, https://nas.er.usgs.gov/queries/greatlakes/FactSheet.aspx?Species_ID=2653, Revision Date: 9/3/2025, Access Date: 12/18/2025
This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.