polytomy


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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 ?
All Jacob's Well samples, surface and subsurface, formed a polytomy within the Eurycea neotenes complex (Fig.
Most taxa were determined within a large polytomy of Podismini, in which only a few clades have been recovered.
In addition, it recovers a polytomy near the base of the Oryzomyalia, with apparent independent origins of the Euneomyini and Andinomys + Punomys clades.
15) and the presence of a connective projection (ch 17), (3) in a polytomy with Oncotheca and Apodytes in 5 trees (Fig.
The strict consensus of the 12 fundamental trees found from the combined analysis using the presence/absence of pigment coding strategy presented a basal polytomy composed by Libelulla herculea, four species of Erythemis and two large clades, one which included the other six species of Erythemis, and a large clade with species of several genera (Fig.
Nevertheless, the tree showed a subsequent polytomy with three large clades at the base of the genus.
2) depicts the Bolivian populations (Taruma and Parque Nacional Carrasco) as more basal (ancestral), sister of the node that includes all the Argentinean populations (Salta, Jujuy and Tucuman) consisting of a polytomy that includes 7/8 of the Tucuman localities (Arroyo Mole Yaco, El Cadillal, Quebrada de Lules, El Molino, Iltico, Arroyo Hornillo and La Sala), a clade that includes a mixture of Jujuy (INTA Yuto and Lagunita Yuto) and Tucuman (Potrero Las Tablas) localities and finally a clade that contains the Salta localities (El Oculto, Parque Nacional El Rey and Aguas Blancas).
Passoa (1995), Berenbaum and Passoa (1999), and the current analysis find that Agonopterix and Exaeretia are sister clades, unlike Kaila's (2004) analysis, where Agonopterix, Depressaria, Exaeretia, and Levipalpus are all part of an unresolved polytomy.
Again, traditional species complexes were recovered but the more basal relationships were poorly supported and the major species groups were collapsed into a polytomy based on weak nodal support
The strict consensus tree indicates that all seven Sarracenia alata representatives appear in an unresolved polytomy (Fig.
cyaneopubescens + Hapalopus)) and in the other tree it traded place in a polytomy with all these clades plus Homoeomma.