Choanoflagellates of the central California waters: Taxonomy, morphology and species assemblages

A qualitative and quantitative survey of nanoplankton communities at offshore Californian localities sampled during September 1989, has revealed a diverse choanoflagellate community consisting of more than 40 taxa, three of which are described as new species (Acanthocorbis haurakiana sp. nov., Parvicorbicula zigzag sp. nov. and Stephanoeca apheles sp. nov.). A biogeographic analysis of the distributional patterns of species encountered indicate that the Californian choanoflagellate fauna consists of species with quasi-cosmopolitan distribution, on top of which is superimposed a contingent of species otherwise associated with warm water regions. A station by station clustering analysis based on the relative abundance counts showed that onshore stations formed a cluster that was significantly different from that formed by offshore stations. Clustering of the PSI values for the species by species matrix revealed two significant clusters, one formed by species found throughout the study area, and one formed by species only encountered in onshore samples. Oligotrophic stations were characterized by high abundances of Pleurasiga minima.