Symmetry in biology Most radially symmetric animals are symmetrical about an axis extending from the center of the oral surface, which contains the mouth to the center of the opposite, , end. Radial symmetry is especially suitable for sessile animals such as the sea anemone, floating animals such as jellyfish, and slow moving organisms such as starfish. Animals in the phyla Cnidaria and Echinodermata are radially symmetric, although many sea anemones and some corals have bilateral symmetry defined by a single structure, the siphonoglyph. Many flowers are radially symmetric or actinomorphic. Roughly identical flower parts – petals, sepals, and stamens – occur at
Bacterial phyla threshold definition by Hugenholtz and Pace: Since then several other candidate phyla have been identified:) Since then a candidate phylum called Poribacteria was discovered, living in symbiosis with sponges and extensively studied. (Note: the divergence of the major bacterial lineages predates sponges) Another candidate phylum, called Tectomicrobia, was also found living in symbiosis with sponges. And "Nitrospina gracilis", which had long eluded phylogenetic placement, was proposed to belong to a new phylum, Nitrospinae. Other candidate phyla that have been the center of some studies are TM7, the genomes of organisms of which have even been sequenced (draft), WS6 and Marine