au·​tap·​o·​mor·​phy ȯ-ˈta-pə-ˌmȯr-fē How to pronounce autapomorphy (audio)
plural autapomorphies
biological taxonomy
: a specialized character or trait that is unique to a monophyletic taxonomic group
… An eversible penis is a synapomorphy that unites lizards and snakes in a common monophyletic group, the Squamata, but is an autapomorphy of the Squamata within a larger monophyletic assemblage.Robert L. Carroll, Patterns and Processes in Vertebrate Evolution, 1997
These species share key traits as autapomorphies of their clade—and since these traits help to construct the relevant environment, sufficient similarity becomes, in part, an active construction of related organisms, not only a happenstance of common externalities.Stephen Jay Gould, The Structure of Evolutionary Theory, 2002
autapomorphic adjective
or less commonly autapomorph
These features are not known for any Jurassic and Cretaceous mammals and are autapomorphic for this new mammalian lineage. Zhe-Xi Luo and John R. Wible, Science, 1 Apr. 2005
autapomorphous adjective
The Chondrichthyes are a monophyletic clade and are principally distinguished on the basis of two unique autapomorphous character sets. Eileen D. Grogan and Richard Lund, in Biology of Sharks and their Relatives, 2004

Word History


autapomorph (borrowed from German, from aut- aut- + apomorph "apomorphic") + -y entry 2

First Known Use

1959, in the meaning defined above

Time Traveler
The first known use of autapomorphy was in 1959

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Dictionary Entries Near autapomorphy

Cite this Entry

“Autapomorphy.” Dictionary, Merriam-Webster, Accessed 16 Apr. 2024.

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