| genetic architecture of the cryptic species complex of acanthocyclops vernalis (crustacea: copepoda). ii. crossbreeding experiments, cytogenetics, and a model of chromosomal evolution. | collectively, populations of acanthocyclops vernalis, a species complex of freshwater copepods, are remarkably similar as to morphology and dna content, despite variability in chromosome number. reproductive isolation had been reported among some populations, but with each new investigation the species boundaries and factors that may influence them appeared less clear. to clarify the pattern of biological species within this group of populations, we adopted a comprehensive approach and examined ... | 2006 | 16610317 |