- Autapomorphy
An autapomorphy in
cladistics is a derived trait that is unique to a given terminal group. That is, it is found only in one member of aclade , but not found in any others oroutgroup taxa , not even those most closely related to the group (which may be aspecies , family or in general any clade).An autapomorphy is not present in the closest relative of the terminal group and also was not present in their common ancestor.
ee also
*
Homoplasy - a trait that is found in several terminal groups but evolved independently (i.e., was not present in their common ancestor)
*Synapomorphy - a trait that is found in some or all terminal groups of a clade, and inherited from a common ancestor, for which it was an autapomorphy (i.e., not present in "its" immediate ancestor).
** Underlying synapomorphy - a synapomorphy that has been lost again in many members of the clade. If lost in all but one, it can be hard to distinguish from an autapomorphy.
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