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.
References in periodicals archive ?
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.
This calculation can be used when several populations or species are being compared simultaneously, for example, in the case of a polychotomy when the phylogeny is unresolved because of an assumed adaptive radiation or multiple speciation event (Maddison 1989).