Final answer:
A novel, derived character is also known as an apomorphy. It helps to identify evolutionary divergence within a lineage and contrasts with a synapomorphy, which is shared among members of a clade.
Step-by-step explanation:
A novel, derived character is also referred to as an apomorphy. In cladistics, an apomorphy is a trait that is newly evolved in a species or a group and is different from the form found in the ancestor of the group. These features are important for determining evolutionary relationships as they can signify a divergence from the ancestral form, leading to the formation of new lineages or clades. When a derived character is shared by members of a group, it is known as a synapomorphy, which helps to define that clade (a group of organisms that includes an ancestor and all of its descendants). Conversely, an ancestral trait found across all members of a group and their common ancestor is known as a plesiomorphy.
For example, considering the amniotic egg characteristic in certain vertebrates, this trait would be considered a shared derived character for those vertebrates that have developed it, as opposed to being a shared ancestral character like the vertebrate backbone.