Basal (phylogenetics)

[4][5][6][n 5] However, such a correlation does not make a given case predicable, so ancestral characters should not be imputed to the members of a less species-rich basal clade without additional evidence.

In describing characters, "ancestral" or "plesiomorphic" are preferred to "basal" or "primitive", the latter of which may carry false connotations of inferiority or a lack of complexity.

[1] The terms ''deep-branching'' or ''early-branching'' are similar in meaning, and equally may misrepresent extant taxa that lie on branches connecting directly to the root node as having more ancestral character states.

The term may be equivocal in that it also refers to the direction of the root of the tree, which represents a hypothetical ancestor; this consequently may inaccurately imply that the sister group of a more species-rich clade displays ancestral features.

The traits of Amborella trichopoda are regarded as providing significant insight into the evolution of flowering plants; for example, it has "the most primitive wood (consisting only of tracheids), of any living angiosperm" as well as "simple, separate flower parts of indefinite numbers, and unsealed carpels".

[14] However, those traits are a mix of archaic and apomorphic (derived) features that have only been sorted out via comparison with other angiosperms and their positions within the phylogenetic tree (the fossil record could potentially also be helpful in this respect, but is absent in this case).

These five species form a clade, the subfamily Homininae (African apes), of which Gorilla has been termed the basal genus.

This fact plus their basal status provides a hint that the most recent common ancestor of extant great apes may have been Eurasian (see below), a suggestion that is consistent with other evidence.

[20][21] Given that the deepest phylogenetic split in a group is likely to have occurred early in its history, identification of the most basal subclade(s) in a widely dispersed taxon or clade can provide valuable insight into its region of origin; however, the lack of additional species in a clade is not evidence that it carries the ancestral state for most traits.

Amborella trichopoda , the most basal extant angiosperm
The phylogenetic tree of marsupials derived from retroposon data shows the basal position of South American Didelphimorphia within Marsupialia , and the basal position of South American Dromiciops within otherwise Australasian Australidelphia . [ 18 ]
Relationship of biogeography and phylogeny of bat superfamily Noctilionoidea inferred from nuclear DNA sequence data, showing the basal position of the Malagasy family Myzopodidae . Locations with only fossil members are indicated by red stars.