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Updated 11/8/02

Figure 1. Left Saccamoeba locomoting towards bottom of page. Middle Saccamoeba showing contractile vacuole (CV) distending the uroid, and the nucleus (N).  A diatom is adhering to the uroid. Right, Bright field image of a Saccamoeba showing cytoplasmic square crystals.

Very similar in appearance to Trichamoeba, except that  the nucleolus is single and central.  The glycocalyx too is similar to Trichamoeba although Page (Page, 1988) has pointed out the similarity of the cup shaped structures of Saccamoeba to those of members of the family Hartmannellidae.   So far only one marine Saccamoeba has been isolated (Anderson et al 1997), although earlier evidence for a marine Saccamoeba had been discussed (see p23, Page 1983). Locomotion is by steady expansion at the leading edge rather than the eruptive expansions of the Vahlkampfiidae. Golgi present as typical stacks.  Some species have cytoplasmic bacteria.  The uroid is much as Trichamoeba, sometimes (not the species in Figure 1) large bulbous with adherant filaments. But some do not have an obvious uroid (e.g. S. limax; and the putative Saccamoeba in Figure 1). Saccamoeba do not have a floating form (if it does its probably a Trichamoeba).  Saccamoeba are usually mono-nucleate. It is noted that Saccamoeba is sometimes polypodal (Page, 1976), especially when changing direction as in Figure 2.  The placement of Saccamoeba within the Family Hartmannellidae and the very similar Trichamoeba in the Family Amoebidae seems incongruous.  However, recent data suggests an affinity between Saccamoeba and Hartmannella (Amaral Zettler et al, 2000). It may be better to disband the Family Hartmannellidae since the genus Hartmannella seems related most closely to Acanthamoeba at least by some SSUrDNA but not all (Amaral Zettler et al, 2000) analysis. More sequences from other genera of amoeba will have to be determined to sort out these relationships, and more than this single Saccamoeba (S.limax ATCC 30942) species to ensure that Saccamoeba is actually monophyletic. Distension of the uroid by the contractile vacuole (see Figure 1, middle) is typical of Saccamoeba but not exclusive to the genus.  Many Saccamoeba produce cysts.  The Saccamoeba featured in Figure 1 could not be identified to species but was obtained from a large freshwater pond in the Penicuik estate, Midlothian, S.E. Scotland.  Note the many square and plate shaped crystals.

Figure 2.  Saccamoeba showing temporary bi-podal locomotive morphology as it changes direction.  The pseudopods advanced smoothly without sudden eruption as in Vahlkampfia.  
Saccamoeba at the Protist Information Server


Saccamoeba angelica  (Bovee, 1972). There is some doubt about this species status as a Saccamoeba (Page, 1988), as it does not have the typical villous uroid. 50-100mm
Saccamoeba limax 35-85mm in length. No cysts. Visible hyaline cap with an oval nucleus of 8mm. 
Saccamoeba limna  (Bovee, 1972) Up to 120mm in length
Saccamoeba lucens (Bovee, 1972). 70-100mm in length. 
Saccamoeba marina (Anderson et al, 1997) 32-102mm in length. The first "certain" marine Saccamoeba, S. marina was isolate from snady surface sediment off the coast of Scotland in the Forth of Clyde.  No observed cysts.
Saccamoeba stagnicola 30-75mm in length.  No cytoplasmic crystals. Cysts circular to oval at 15mm in diameter. Has a spherical nucleus 6.5mm dia.  
Saccamoeba wakulla   (Bovee, 1972) To 175mm in length. Oval nucleus 3.5-6.5mm. no cysts. Locomotes with a steady flattened pseudopod with a distinct hyaline layer.
Strains available:-
ATCC 30942  Saccamoeba limax (F-13) Griffin, J.L. Lincoln Woods State Park Providence RI. 1962 . SSUrDNA AF293xxx,
ATCC 30943 Saccamoeba sp. (F-71) Griffin, J.L. Riveway Pond, Boston, MA
ATCC 30944 Saccamoeba limax (F-150) Griffin, J.L. Potomac River, Washington, DC. 1975
CCAP 1534/6 Saccamoeba limax Page, F.C. Lake Tuskegee, AL. 1966
CCAP 1572/3 Saccamoeba limax Page, F.C. Loch Morar, Scotland. 1977
CCAP 1572/1 Saccamoeba stagnicola Page, F.C. Coe Fen, Cambridge England 1972
CCAP 1572/2 Saccamoeba stagnicola Page, F.C. Pond, Harlton, Cambridge England 1972


Amaral Zettler, L.A., Nerad, T.A., O'Kelly, C.J., Peglar, M.T., Gillevet, P.M., Silberman, J.D. & Sogin, M.L. (2000). A molecular reassessment of the Leptomyxid amoebae. Protist 151, 275-282.

Anderson, O.R., Rogerson, A. & Hannah, F. (1997). Three new limax amoebae isolated from marine surface sediments: Vahlkampfia caledonica N. Sp., Saccamoeba marina N. Sp., and Hartmannella vacuolata N.Sp. J.Euk.Microbiol. 44(1), 33-42.

Bovee, E.C. (1972). The lobose amoebas IV. A key to the order granulopodida Bovee & Jahn, 1966, and descriptions of some new and little-known species in this order.  Arch.Protistenk. 114: 371-403.

Grebecki, A. (1987). Locomotion of Saccamoeba limax. Arch.Protistenk. 134: 347-365.

Page, F.C. (1976). An illustrated key to freshwater and soil amoebae. Ambleside, Freshwater Biology Association.

Page, F.C. (1983) "Marine gymnamoebae". Inst.Terr.Ecol. NERC.

Rohr, U., Weber, S., Michel, R., Selenka, F. & Wilhelm, M. (1998) Comparison of free-living amoebae in hot water systems of hospitals with isolates from moist sanitary areas by identifying genera and determining temperature tolerance. App.Environ.Microbiol. 64, 1822-1824.

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