Definition: 1) Producing live offspring from within the body of the parent (Lincoln et al., 1998). 2) Development of an embryo within the body of the parent, in part, resources passing directly from parent to embryo (Barnes et al., 2006).
Definition: 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.