The vampyrellids are a small group of
protists with filose pseudopods and lacking shells. "Vampyrella" is typical of the group. When free-floating, the cell is spherical and around 30 μm across, with long radially directed filose pseudopods as well as distinctive shorter club-shaped ones, so that it resembles a heliozoan. Moving, the cell stretches out and takes a more typical amoeboidform, with an obvious distinction between the clear periphery and pseudopods and the greenish interior. In this form it finds its way into algae cells and feeds on their interiors. A few other vampyrellids are parasitic on fungi. As such, these vampyrellids can be an important control of parasitic rust fungus of wheatand other crops.
Vampyrellids characteristically have mitochondria with tubular
cristae. Together with the nucleariids they include the majority of the naked filose amoebae. They have been considered possible members of the Cercozoa, but at present their relationship to other protists is uncertain.
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