Crown group

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Root group and crown group in an abstract example.

Crown group is a term from the phylogenetic system and describes a clade , at the basis of which the last common ancestor of all recent taxa of this clade is. Besides the mentioned recent taxa, only those fossil representatives belong to the crown group that also go back to this last common ancestor.

Home group

The parent line or parent group is the paraphyletic ancestor group of a crown group, to which all fossil taxa belong that are more closely related to this crown group than to any other recent group, but do not belong to the crown group itself. For example, the "non-avian dinosaurs", the pterosaurs and the silesaurids belong to the ancestral group of birds, since the birds have a last common ancestor with them, which is younger than the last common ancestor with their closest relatives living today, the crocodiles.

Pan group

The crown group and the main group together form the monophyletic pan group (also called total group ). The recent mammals form the synapsid crown group, the non-mammal therapsids together with the “ Pelycosauria ” form the mammalian parent group and the synapsida as such form the pan group.

swell

  • Philip CJ Donoghue: Saving the stem group - a contradiction in terms? Paleobiology 31 (4), 2005, pp. 553-558.
  • B. Wiesemüller, H. Rothe, W. Henke: Phylogenetic systematics. Springer, 2003, ISBN 3-540-43643-X .