Penard Labs

The Fascinating World of Amoebae
Vampyrellida West 1901, emend. Hess et al. 2012
Exclusively heterotrophic, naked, phagotrophic amoeboid organisms; life cycle includes amoeboid, free-moving trophozoites alternating with an obligatory digestive cyst, in which cell division usually take place; several taxa can fuse to form plasmodia and reach considerable sizes; sexual processes unknown; cytoplasm often differentiated into a finely granular, sometimes highly vacuolated part and structure-less hyaloplasm, the latter often surrounding the main cell body, but at least constituting the pseudopodia; free-living in freshwater, soil, or marine environments.

1. Vampyrellidae Zopf 1885, emend. Hess et al. 2012
Exhibiting straight, tapering and occasionally branching filose pseudopodia. Trophozoites of known members perforate algal cell walls and phagocytose only the cell contents; thus seemingly strictly specialized on the food organisms. Cells show intense orange color due to the algal diet, except directly after phagocytosis when the cells are green.

1.1. Vampyrella Cienkowsky 1865
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Vampyrella closterii Poisson and Mangenot 1933
Food particles often larger, 0.5-1.5 µm granules (membranosomes) moving along the filopodia.

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Vampyrella pendula Cienkowski 1865
Pseudopodia without membranosomes. Feeds on Oedogonium.

1.2. Hyalodiscus Hertwig and Lesser 1874
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Hyalodiscus rubicundus Hertwig and Lesser 1874

2. Leptophryidae Hess, Sausen and Melkonian 2012
Cells spreading on surfaces in the trophic phase, continuously changing their outline and therefore extremely variable in size and shape (e.g. irregular branched, elongate, anastomosing, network-forming). Filopodia thin, tapering, occasionally ensiform; sometimes branching or dendritic; often emerging from hyaloplasmatic fringes at the cell margins; sometimes in tufts. Cells move by incessant creeping. Food items are engulfed as a whole (e.g. unicellular or colonial algae, fragments of algal filaments, fungal spores, yeast cells and small metazoans) or opened by local perforation of the cell wall. Color of granuloplasm varies with food source; colorless or pale, algivorous members occasionally show yellowish, brownish or orange tint. Size and shape of digestive cysts depend on the food source; cysts sometimes resembling the outline of the prey.

2.1. Leptophyrs Hertwig and Lesser 1874
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Leptophrys vorax (Cienkowski 1865) Zopf 1885

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Leptophrys vorax trophozoite before encystment

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Leptophrys vorax digestive cyst

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Leptophrys vorax empty digestive cyst

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Leptophrys vorax trophozoite, empty cyst with hole, full digestive cyst

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Leptophrys vorax trophozoites leaving digestive cyst

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Leptophrys vorax trophozoite
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Leptophrys vorax empty cysts