Pseudorinelepis, the most basal group, is found only in the Amazon basin.

This family was found to be the most basal group of Notosuchia.

The Prasinophyceae may be a paraphyletic basal group to all green plants.

They included a number of basal tetrapod groups classified in early books under the Labyrinthodontia.

They are separate from the lydekkerinids, which remain a basal group of stereospondyls.

This is supported by the fact that some basal groups do not show bioluminescence and, rather, use chemical signaling.

It is used for groups which have evolved from a more basal group.

Within the second clade the respiroviruses appear to be the basal group.

It is probable that this family represents a basal group in which intermediates have disappeared.