clade

Etymology

From Ancient Greek κλάδος (kládos, “shoot, branch”). Coined by British evolutionary biologist, philosopher and author Julian Huxley in 1957 in a paper titled "The three types of evolutionary process" in Nature. Doublet of cladus.

noun

1. (systematics) A group of animals or other organisms derived from a common ancestor species.
   All three clades containing Prunum and “Volvarina” species contain morphological features that do not collectively appear in any other living or fossil marginellid species (see above). 2001, Ross H. Nehm, “6: Linking Evolutionary Pattern and Development Process in Marginellid Gastropods”, in Alan H. Cheetham, Jeremy B. C. Jackson, Scott Lidgard, Frank K. McKinney, editors, Evolutionary Patterns: Growth, Form, and Tempo in the Fossil Record, page 166
   No one has ever tabulated the number or percentage of non-trending clades within larger monophyletic groups. The concept of a non-trending clade — the higher level analog of a species in stasis — has never been explicitly formulated at all. If only one percent of clades exhibited sustained trends, we would still focus our attention upon this tiny minority in telling our favored version of the story of life's history. 2002, Stephen Jay Gould, The Structure of Evolutionary Theory, page 1092
   A clade is made up of an ancestral species and all its descendants; think of it as that part of an evolutionary tree that would fall off with a single saw cut. September 11 2004, Bob Holmes, Linnean naming system faces challengers, New Scientist, page 13
2. (genetics) A higher level grouping of a genetic haplogroup.

verb

1. To be part of a clade; to form a clade.
   The phylogenetic tree for CiCBR shows it clades with the human cannabinoid receptors rather than with those other human GPCRs which most closely resemble the cannabinoid receptors. 2009, Andrew J. Brown and C. Robin Hiley, "Is GPR55 an Anandamide Receptor?" in Anandamide An Endogenous Cannabinoid (Vitamins And Hormones, Vol. 81), p. 117