Specific status of Keratella cochlearis (Gosse) and K. earlinae Ahlstrom (Rotifera: Brachionidae): morphological and ecological considerations

Keratella cochlearis and K. earlinae were found to coexist in a shallow eutrophic lake in western Canada. Differences between the two populations were found with respect to size, shape, seasonal abundance, birth rate, and vertical distribution. Results suggest that the two populations represent stable species and not ecophenotypes as suggested by recent literature.