Asterocaelum
- Asterocaelum algophilum Canter, 1973 (ref. ID; 4670)
Comments
The species is spherical or elongate, and has broad based, tapering, radiating pseudopodia, is similar to Nucleosphaerium, but has certain differences. The main differences in the morphology of the two genera are that A. algophilum readily adopts a typical mobile amoeboid form, and that the pseudopodia are form a broad hyaline base, and frequently branch. These is present in A. algophilum what could be an axial filament in some of the processes, taking the form of a core of dense material in light microscope observations. Carter reports that the cell body content of A. algophilum is granular with orange globules. No such colourations is observed in Nucleosphaerium. A. algophilum, furthermore, may be uni- or multinucleate, and any vacuoles present are rarely contracting. The life cycle of A. algophilum is much more complex than that of N. tuckeri. No fusion of individuals was observed, but the author considered that this might occur. Encystment occurs after feeding, and reproduction is either by division or encystment followed by liberation of young amoebae. A. algophilum is, however, an algal feeder, mainly devouring centric diatoms, and the importance of these organisms in controlling the numbers of algae is mentioned (Canter & Lund 1968). The possible presence of internal rod bacteria in A. algophilum is mentioned, also the presence of a mucilaginous envelope (Carter 1973). (ref. ID; 4670)