Skeletal and cytoplasmic variability of large spongiose spumellarian radiolaria (Actinopodea: Polycystina)

Abstract

Large, spongiose skeletal radiolaria occur abundantly in tropical and some subtropical oceanic locations. There is substantial variability in skeletal and cytoplasmic morphology and the major skeletal features used by Haeckel and others to discriminate among species intergrade to such a degree that it is not possible in most circumstances to make a clear taxonomic distinction. There is no correlation between the kind of symbiont associated with the host and its skeletal organization. There is a nearly continuous variation in cytoplasmic organization of the central capsules. There is no correlation between the degree of ontogenetic sequence progressing from a large, centrally located nucleus with loose, radially-arranged cytoplasmic lobes toward increasingly dispersed nuclear lobes distributed into the peripheral cytoplasm containing abundant reserve bodies. -from Authors