Description
Heliozoa (colloquially called the desmothoracids) with body located in a perforated, extracellular and usually stalked lorica. Cells with single central nucleus. Long, sometimes forked axopodia extend through the pores of the capsule. Axonemes terminate on the nuclear envelope. Microtubular cristae are tubular. Extrusomes are complex and resemble those of some cercomonads. There is a complex life cycle with the trophic heliozoan stage dividing by binary fission . Ole daughter may become a free-swimming form with one (in one species) or two flagella, which settles to form an amoeba, subsequently developing stiff pseudopodia and eventually secreting the capsule and stalk . Products of division may encyst within the capsule. Stalked capsules may join end-to-end to form colonies. With three genera and 11 species . References : Bardele (1972), Brugerolle (1985), Siemensma (1991 ). b LM 1. Capsule is lattice-like , with large openings .. .. . . ... . . ... .. . . . .. . . . . . . . . . . . . . ... . . .. . . .. . . . 1'. Capsule is non-lattice-like, pores or small openings .... ........ ..... ...... .. ... ..... . 2 2. Capsule tapers into a short conical stalk ......... . . .. .. .. .. . .. .. .. .. . .. .. . ... .. . .. . ... . .. . ... . .. .. . 2' . Capsule is sharply differentiated from a long tube-like stalk ... ........... ........... Hedriocystis
Type species
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Raw text
Heliozoa (colloquially called the desmothoracids) with body located in a perforated, extracellular and usually stalked lorica. Cells with single central nucleus. Long, sometimes forked axopodia extend through the pores of the capsule. Axonemes terminate on the nuclear envelope. Microtubular cristae are tubular. Extrusomes are complex and resemble those of some cercomonads. There is a complex life cycle with the trophic heliozoan stage dividing by binary fission . Ole daughter may become a free-swimming form with one (in one species) or two flagella, which settles to form an amoeba, subsequently developing stiff pseudopodia and eventually secreting the capsule and stalk . Products of division may encyst within the capsule. Stalked capsules may join end-to-end to form colonies. With three genera and 11 species . References : Bardele (1972), Brugerolle (1985), Siemensma (1991 ). b LM 1. Capsule is lattice-like , with large openings .. .. . . ... . . ... .. . . . .. . . . . . . . . . . . . . ... . . .. . . .. . . . 1'. Capsule is non-lattice-like, pores or small openings .... ........ ..... ...... .. ... ..... . 2 2. Capsule tapers into a short conical stalk ......... . . .. .. .. .. . .. .. .. .. . .. .. . ... .. . .. . ... . .. . ... . .. .. . 2' . Capsule is sharply differentiated from a long tube-like stalk ... ........... ........... Hedriocystis