polytomy

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Related to Polychotomy: polychotomous

polytomy

(pə-lĭt′ə-mē)
n.
In a cladogram, a point from which two or more new branches diverge, representing either of two cases:
a. A multiple speciation event in which two or more species diverge from the same ancestor. Also called hard polytomy.
b. A speciation event in which two or more species are presumed to descend from the same ancestor, but the order of speciation is unknown. Also called soft polytomy.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
References in periodicals archive ?
Polychotomy is simply the next logical step in the progression of auditory experimental tasks.
Knowledge representation-whether in the mind, on the shelf, or over the Internet--is still subject to the polychotomy of human expression and classification.
mortenseni constitute an unresolved polychotomy (metaphyletic grouping), at the base of the cladogram.