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

Haplomyxa spec.

Main cell body Haplomyxa spec. Description: The cell had a cylindrical flattened body from which numerous granuloreticulopodia emerged. The common shape was more or less

Read More »

Valkanovia delicatula

V. delicatula, after Valkanov, 1962 Genus Valkanovia  Tappan, 1966 Diagnosis: Shell ovoid, oblate, elliptical in cross-section, composed of elongated elliptical hyaline scales arranged in a

Read More »

Gocevia pontica

Gocevia pontica, after Valkanov, 1934 Gocevia pontica Valkanov, 1934 Diagnosis: Clearly addressed bipolarity. Body covered by a weakly flexible tectum covered with foreign bodies. The

Read More »

Nabranella

N. brevis, after Snegovaya and Alekperov, 2009 Genus Nabranella Snegovaya and Alekperov, 2009 Diagnosis: Shell oval or spherical shape without neck. Apical top flat and

Read More »

Armipyxis

Genus Armipyxis Dekhtiar, 2009 Genus Armipyxis was created by Dekhtiar (2009) to accommodate all species with internal struts. However, C. aculeata may also have struts, although

Read More »

Netzelia pseudolimnetica

N. pseudolimnetica, after Penard, 1902 Netzelia pseudolimnetica Ogden and Meisterfeld, 1989 Synonym Difflugia limnetica (Levander, 1900) Penard, 1902. D. limnetica – Pejler, 1962, Oikos, 12,

Read More »

Cylindrifflugia hiraethogii

C. hiraethogii, after Ogden. 1983 Cylindrifflugia hiraethogii (Ogden, 1983) González-Miguéns et al., 2022 Diagnosis: the shell is light yellow or transparent, thin pyriform with a distinct

Read More »

Cylindrifflugia bacillariarum

  C. bacillariarum, 103 – 114 µm – Fochteloërveen, Netherlands   Cylindrifflugia bacillariarum (Perty, 1849) n. comb. González-Miguéns et al., 2022 Diagnosis: shell transparent, colorless or

Read More »

Cylindrifflugia elegans

C. elegans, length 84-102 µm, Gaasterland Cylindrifflugia elegans (Penard, 1890) n. comb. González-Miguéns et al., 2022 Basionym: Difflugia elegans Penard, 1890 Diagnosis: shell outline rough, pyriform

Read More »

Cylindrifflugia lanceolata

C. lanceolata, shells 153-169 µm long, nuclei 23-26 µm (Naardermeer, Netherlands) Cylindrifflugia lanceolata (Penard, 1890) n. comb. González-Miguéns et al., 2022 Basionym: Difflugia lanceolata Penard,

Read More »