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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.

[poly- + -tomy (on the model of dichotomy).]
References in periodicals archive ?
Tenders are invited for Medical devices (cannulated tools for traumatology); a set of instruments for the polytomy of the nose; a set of instruments for performing operations on the larynx; controlled balloon tamponade; complex vacuum system of obstetrics KIW
Those authors found the Jacob's Well specimens to fall within a large Eurycea complex polytomy that includes salamanders from sites recognized to have E.
galloprovincialis-SH clustered into a large polytomy indicating considerable uncertainty in the relationship among these taxa.
2014) or as a clade within a polytomy that also includes Chinchillula and Reithrodon (see Carrizo and Catalano, in press).
philippinensis from Okinawa as a polytomy with two Phallusia samples from GenBank from India and the Mediterranean coast of Israel, while P.
7) shows that the fossil taxon, Solanites brongniartii, is found in a polytomy in the first node of the Euasteridae along with eight individual terminals and nine clades.
12 subgroup and the phylogenetic pattern of a long branch leading to a polytomy with genetic homogeneity point to a possible adaptive advantage for this subgroup.
The wing veins subset offered a tree where most of the Erythemis species are located in a large basal polytomy and others are in other sections of the tree (Fig.