The application of electrophoresis to the systematics of the marine dinoflagellate genus Heterocapsa

Eight strains (and three subcultures of one strain) of four species of the marine dinoflagellate genus Heterocapsa ( H. illdefina, H. niei, H. pygmeea, and H. triquetra) were assayed electrophoretically for enzymes encoded by four loci. Additionally, electromorphs of the peridinin-chlorophyll a-protein pigment complex were investigated. A roote Wagner tree was constructed and indicates evolutionary lines of descent, as well as the degree of relatedness between subcultures, isolates, and taxa. There was a correlation between the degree of geographical isolation and taxonomic distance as determined from electrophoresis. Minor electrophoretic differences were detected among four subcultures of H. pygmaea that were prepared 25 years ago. The present morphologically derived classification of this genus agrees with our biochemically based systematic scheme with one exceptin. One of the isolates previously identified as H. pygmaea is considered an undescribed, possibly sibling species.