Microworld

world of amoeboid organisms

Menu
Massisteria spec. Fresh water; cilia are arrowed

Genus Massisteria Patterson & Fenchel, 1990

Diagnosis: small body, usually under 5 µm, which in trophic organisms emits curving, sometimes branched fine pseudopodia with extrusomes, and have two cilia lying inactive over the body surface. Under some circumstances, the arms may be resorbed and the organism will swim actively. Trophont does not move actively, feeds usually on bacteria. Multicellular forms are encountered.

Type species: Massisteria marina Larsen and Patterson, 1990

Remarks: This genus has only been reported from marine sites all over the world, but recently (2012) I found specimens in moist-chamber-mounts from fresh water samples (see the photomicrographs here) which closely resemble Massisteria. These specimens seem to live inside a kind of shell which is hard to detect light microscopically. Probably they represent a Microcometes species. The resemblance between Massisteria and Microcometes has also been noted by Lee et al (2005). The only difference at light microscopic level is the presence of a shell in Microcometes.
Specimens of Massisteria are light microscopically very similar to Limnofila. The only distinction seems to be the presence or absence of the two cilia.

 

Massisteria marina Larsen and Patterson 1990

Diagnosis: Organism with an irregular star-shaped body from which radiate thin pseudopodia with extrusomes. There are 2 inactive flagella. The organism is normally sedentary but, under adverse conditions, the arms are resorbed, the flagella become active, and the organism becomes a motile non-feeding flagellate.

Remarks: This small phagotrophic protist is associated with sediment particles and with suspended detrital material in littoral and oceanic marine waters. It has been found at sites around the world.

Literature: Patterson, D. J. and Fenchel, T.: Massisteria marina Larsen and Patterson 1990, a widespread and abundant bacterivorous protist associated with marine detritus. – Marine ecology progress series. Oldendorf  Vol. 62, no. 1-2, pp. 11-19. 1990.

Recent posts

Reticulomyxa hannae

R. hannae, plasmodium – photomicrograph Steffen Clauß Reticulomyxa hannae Völcker and Clauß, 2020 Diagnosis: Trophozoites surrounded by a very thin mucous envelope, with slowly moving plasmodia, variable

Read More »

Velamentofex

Velamentofex tyrolensis (photomicrograph Steffen Clauß) Family Velamentofexidae Völcker and Clauß, 2020 Diagnosis: Multinucleate organic-walled monothalamous foraminifera. Test spherical to pyriform, usually surrounded by a broad

Read More »

Claparedellus lachmannii

Claparedellus lachmannii, common shape (Riedensee) Claparedellus lachmannii  Khanipour Roshan and Clauß, 2020 Diagnosis: Multinucleate organic-walled monothalamous foraminifera. Test spherical to elongated pyriform or irregularly shaped, with a

Read More »

Claparedellus

Claparedellus lachmannii Genus Claparedellus Khanipour Roshan and Clauß, 2020 Diagnosis: Multinucleate organic-walled monothalamous foraminifera. Test spherical to elongated pyriform or irregularly shaped, with a hyaline, flexible,

Read More »

Velamentofex tyrolensis

V. tyrolensis (photomicrograph Steffen Clauß) Velamentofex tyrolensis Völcker and Clauß, 2020 Diagnosis: Trophozoites ovoid, 98-125 μm, with reticulopodia up to 300 μm long, with a hyaline,

Read More »

Velamentofex saxonensis

V. saxonensis, feeding (photomicrograph Steffen Clauß) Velamentofex saxonensis Völcker and Clauß, 2020 Diagnosis: Trophozoites ovoid, 30-95 μm, granuloreticulopodia up to 1000 μm long. with a hyaline, thin

Read More »