Descriptions of Spiniferomonas silverensis sp. nov. and S. minuta sp. nov. and an assessment of form variation in their closest relative, S. trioralis (Chrysophyceae)

Abstract

Two new species of the planktonic noncolonial chrysophyte genus Spiniferomonas (S. silverensis sp. nov. and S. minuta sp. nov.) are described from several localities in Ontario, Canada. Scale structure is distinctive and does not integrate with scale structure of their closest relative, S. trioralis Tak. Spiniferomonas trioralis is very common in Ontario; its scale structure is relatively constant with the exception of spine-scale length, which in the Ontario specimens ranged from 4 to 24 μm. The highest observed ratio of longest to shortest spine scale on individual cells was 2.3:1. It is now apparent that the form f. cuspidata Balonov should be abandoned, since there are apparently no differences other than spine length separating this form from f. trioralis.