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
Tullimonstrum characteristics of the well-known modern phyla, it was speculated that it was representative of a stem group to one of the many phyla of worms that are poorly represented today. Similarities with Cambrian fossil organisms were noted. Chen "et al." suggested similarities to "Vetustovermis planus". Others pointed to a general resemblance between "Tullimonstrum" and "Opabinia regalis", although Cave "et al." noted that they were too morphologically dissimilar to be related. In 2016 a morphological study showed that "Tullimonstrum" may have been a basal vertebrate, and thus a member of the phylum Chordata, with one study suggesting "Tullimonstrum" may be closely