Not all ctenophores are hermaphrodites. Studies on the systematics, distribution, sexuality and development of two species of Ocyropsis

摘要: The lobate ctenophores Ocyropsis maculata and O. crystallina are not simultaneous hermaphrodites, based on morphological, histological experimental evidence. Sex ratios in populations, sex of size classes within average sizes males females support the hypothesis that both species dioecious, rather than sequential hermaphrodites. We have divided each into two subspecies, morphology geographic distribution. Preliminary evidence suggests subspecies also differ reproductive behavior. One guttata, spawns a daily cycle laboratory, spawning becomes more synchronous when placed together. Species Ocyropsis, all which oceanic distribution, probably descended from common ancestor was hermaphrodite. That this group evolved dioecy directly contradicts assertion there is selective advantage to hermaphroditism environments where probability finding mate reduced.