التعريف: overall repetitive or reflective pattern in the body of one individual of this taxon. eg: bilateral symmetry, rotational symmetry, radial symmetry
التعريف: a type of locomotion in which an animal moves on a secreted layer of mucus, propelled by the beating of cilia. It is characteristic of small, soft-bodied invertebrates.
التعريف: The number of fossil occurrences in the Paleobiology Database (https://paleobiodb.org) that are identified as belonging to a particular taxon or any of its subtaxa.
التعريف: Eye-spots which may be set into a pit to reduce the angles of light that enters, to allow the organism to deduce the angle of incoming light. Lens-like structures may be present, but stemmata, unlike lens eyes, cannot form an image, either for lack of refractive power or retinal resolution.
