heliozoan

heliozoan
/hee'lee euh zoh"euhn/, n.
1. a protozoan of the order Heliozoa, having a spherical body and radiating pseudopods.
adj.
2. Also, heliozoic /hee'lee euh zoh"ik/. belonging or pertaining to the Heliozoa.
[1890-95; < NL Heliozo(a) name of the group (see HELIO-, -ZOA) + -AN]

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      any member of the protozoan class Heliozoea (superclass Actinopoda). Heliozoans are spherical and predominantly freshwater and are found either floating or stalked. They are frequently enveloped by a shell (or test) composed of silica or organic material secreted by the organism in the form of scales or pieces in a gelatinous covering. The secretions exhibit a wide variety of shapes, which may help in species identification. The numerous radiating cytoplasmic masses, called pseudopodia (pseudopodium) (axopodia), are used more for capturing food than for locomotion. Heliozoans ingest protozoans, algae, and other small organisms and reproduce asexually by binary fission or by budding. Flagellated forms, which may be gametes, have been described in several genera.

      Actinophrys sol is a common species often referred to as the sun animalcule. Acanthocystis turfacea is a similar species commonly called the green sun animalcule because its body is coloured by harmless symbiotic green algae (zoochlorellae). Actinosphaerium species are multinucleate, often reaching a diameter of 1 mm (0.04 inch).

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Universalium. 2010.

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  • heliozoan — [hē΄lē ə zō′ən] n. [< ModL Heliozoa (< HELIO + ZOA) + AN] any of a class (Heliozoa) of chiefly freshwater protozoans with slender pseudopodia arranged as rays heliozoic [hē΄lē ə zōik] adj …   English World dictionary

  • heliozoan — noun protozoa with spherical bodies and stiff radiating pseudopods • Hypernyms: ↑actinopod • Member Holonyms: ↑Heliozoa, ↑order Heliozoa * * * adjective or noun see heliozoa * * * /hee lee euh zoh euhn/, n …   Useful english dictionary

  • heliozoan — noun Etymology: New Latin Heliozoa, from 1heli + zoa Date: circa 1889 any of a class (Heliozoa) of free living spherical usually freshwater protozoans that reproduce by binary fission or budding …   New Collegiate Dictionary

  • heliozoan — noun Any of a group of aquatic protozoans, of the order Heliozoa, that have spherical bodies from which radiate spindlelike pseudopods …   Wiktionary

  • heliozoan — he·lio·zo·an …   English syllables

  • heliozoan — he•li•o•zo•an [[t]ˌhi li əˈzoʊ ən[/t]] n. 1) ivt any protozoan of the order Heliozoa, having a spherical body and radiating pseudopodia 2) ivt Also, he li•o•zo′ic. of or pertaining to the heliozoans • Etymology: 1890–95; < NL Heliozo(a) (see… …   From formal English to slang

  • heliozoan — /hiliəˈzoʊən/ (say heeleeuh zohuhn) noun 1. any of the mostly freshwater group Heliozoa, an order of protozoans, distinguished by a spherical body and radiating pseudopodia. –adjective 2. belonging or relating to the Heliozoa. {helio + zo(a) +… …  

  • helioflagellate — Any of a class of freshwater protozoans. They are sometimes considered relatives of heliozoans (organisms that for movement have extensions of cytoplasm called pseudopodia, but no flagella) because of their slender, radiating pseudopodia. The… …   Universalium

  • sun animalcule — noun : a protozoan of the order Heliozoa; especially : a large freshwater protozoan (Actinophrys sol) with numerous flexible radiating axopodia * * * a heliozoan. [1865 70] * * * sun animalcule noun A heliozoan • • • Main Entry: ↑sun …   Useful english dictionary

  • he|li|o|zo|ic — «HEE lee uh ZOH ihk», adjective. = heliozoan. (Cf. ↑heliozoan) …   Useful english dictionary

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