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Ultrastructure and Ecology of Calycomonas ovalis Wulff, 1919, (Chrysophyceae) and Its Redescription as a Testate Rhizopod, Paulinella ovalis N. Comb. (Filosea: Euglyphina) 1
Author(s) -
JOHNSON PAUL W.,
HARGRAVES PAUL E.,
SIEBURTH JOHN McN.
Publication year - 1988
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1988.tb04160.x
Subject(s) - biology , ultrastructure , botany , flagellum , paleontology , bacteria
An exceptional bloom (10 9 cells/liter) of a unicellular alga, Aureococcus anophagefferens , in Narragansett Bay, RI, was accompanied by unusually high numbers (6 times 10 6 tests/liter) of vase‐shaped cells of Calycomonas ovalis Wulff, hitherto considered a flagellated chrysophyte. Phase contrast light microscopy showed the characteristic oval lorica or test of C. ovalis , ca. 3.0 times 4.5 μm. Transmission electron microscopy of thin sections of natural populations revealed, however, that C. ovalis is actually a rhizopod within a test of electron‐dense scales. This estuarine, planktonk testacean extends a pseudopodium through a narrow pseudostome and lacks chloroplasts or flagella. It is a bacterivore and feeds primarily on unicellular cyanobacteria. The morphology, ultrastructure, and cell division of C. ovalis are described. These characteristics place C. ovalis with the genus Paulinella (Sarcodina: Filosea: Euglyphina), which at present contains the single species, P. chromatophora Lauterbom. Calycomonas ovalis is thus assigned to Paulinella as P. ovalis n. comb.