Reproductive strategies in the bryozoa: morpho-anatomical diversity and systematics, and evolutionary significance

The various patterns of embryogenetical, larval and morphological strategies of development known among the Bryozoa, ontogenetically pre-programated phenomena, peculiarly characterized by the distinct destinies of the endodermic primordium according to the evolutive ligneages, correspond to so much reproductive models for ameliorate the survival, the capacities of dispersion and the prosperity of these given species. It is matter, according the structures of the larvae, the phylogenetic lineages and consequently the taxa, of plantotrophy, transformation of an abortive alimentary canal to an energetic reserve or to an amorphic mineral concretions, or to a most ordinary lecitotrophy without a particular regression. Beyond the direct budding on new zoecia, are known in some of these evolutive series another whole of strategies of reproduction: the capacity of an asexual reproduction. The latter corresponds to some different modalities: nautozoids, sessoblasts, flottoblasts, succuli, hibernacles; in other groups, the authors pointed out phenomena of polyembryony (cyclostomes) or of viviparity (phylactolaemates ). The various aspects are analyzed and interpretated according the phylogenetic lineages, the delimitation and the definition of the taxa, and also the advantages drowed by the organisms.