Terminology
The relationship between clades can be described in several ways:
- A clade located within a clade is said to be nested within that clade. In the diagram, the hominoid clade, the apes and humans, is nested within the primate clade.
- Two clades are sisters if they have an immediate common ancestor. In the diagram, lemurs and lorises are sister clades.
- A clade A is basal to a clade B if A branches off the lineage leading to B before B 's first member. In the diagram to the right, the strepsirrhine clade, including the lemurs and lorises, is basal to the hominoids, the apes and humans. Some authors have used "basal" differently to mean a clade that is "more primitive" or less species-rich than its sister clade; others consider this usage to be incorrect.
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