Description
Heliozoa with axonemes arising from a central homogeneous axoplast and the microtubules in the axonemes arranged in irregular hexagonal prisms . One eccentric nucleus or multiple nuclei; mitochondrial cristae are tubular; different types of extrusomes . Usually attached to the substrate by a cytoplasmic stalk ; with the cell body differentiated into a 'head ' with radiating axopodia and an extensive multinucleate amoeboid base. The stalk of Actinocoryne is contractile . May occasionally be free-swimming. Cell surface may be covered by tangential siliceous (?) spicules, mucus, or be naked . Life cycle is complex but not fully resolved . Actinocoryne may produce multiple buds from the 'head' which form small , temporarily floating , spherical, amoeboid cells. Motile cells with two flagella are produced by Gymnosphaera and Actinocoryne (possibly with an annual cycle) . Three monotypic marine genera. References : Febvre-Chevalier ( 1 9 8 0 , 1990), Jones (1976). GYMNOSPHAERIDAE,;, bLM 1. Cell surface naked or covered with a thin mucus coat .. ...... .. .................. ....... .. .... ...... . 1'. Cell surface wi th mucus and tangential siliceous (?) spicules , uninucleate, attached or floating ................ .. .............. Hedraiophrys 2. Unattached, multinucleate, with cytoplasm differentiated into ecto- and endopla ..... .. ... ......... .......... ..... .. ............ Gymnosphaer 2'. Attached , with a contractile cytoplasmic stalk and an extensive multinucleate amoeboid base; cytoplasm uniform .. ............ .. .. .. Actinocoryne
Type species
Figures
No linked figures.
Raw text
Heliozoa with axonemes arising from a central homogeneous axoplast and the microtubules in the axonemes arranged in irregular hexagonal prisms . One eccentric nucleus or multiple nuclei; mitochondrial cristae are tubular; different types of extrusomes . Usually attached to the substrate by a cytoplasmic stalk ; with the cell body differentiated into a 'head ' with radiating axopodia and an extensive multinucleate amoeboid base. The stalk of Actinocoryne is contractile . May occasionally be free-swimming. Cell surface may be covered by tangential siliceous (?) spicules, mucus, or be naked . Life cycle is complex but not fully resolved . Actinocoryne may produce multiple buds from the 'head' which form small , temporarily floating , spherical, amoeboid cells. Motile cells with two flagella are produced by Gymnosphaera and Actinocoryne (possibly with an annual cycle) . Three monotypic marine genera. References : Febvre-Chevalier ( 1 9 8 0 , 1990), Jones (1976). GYMNOSPHAERIDAE,;, bLM 1. Cell surface naked or covered with a thin mucus coat .. ...... .. .................. ....... .. .... ...... . 1'. Cell surface wi th mucus and tangential siliceous (?) spicules , uninucleate, attached or floating ................ .. .............. Hedraiophrys 2. Unattached, multinucleate, with cytoplasm differentiated into ecto- and endopla ..... .. ... ......... .......... ..... .. ............ Gymnosphaer 2'. Attached , with a contractile cytoplasmic stalk and an extensive multinucleate amoeboid base; cytoplasm uniform .. ............ .. .. .. Actinocoryne