As a rule of thumb, a Bremer score of 3 is good and a score of 5 is “highly supported.”
Bootstrapping calculates a support value for each node based on the fraction of samples that support that node. The highest support value is 100, while values below 70 are usually considered weak. Values below 50 aren’t shown; in fact, branches below 50 are collapsed and shown as a polytomy.
Gradual Assembly of Avian Body Plan Culminated in Rapid Rates of Evolution
across the Dinosaur-Bird Transition (Supplemental Information)
Stephen L. Brusatte, Graeme T. Lloyd, Steve C. Wang, and Mark A. Norell
This clade—Maniraptoriformes—is only poorly supported (Bremer support of 1 and jackknife percentage of less than 50%), and relationships at its base are unresolved. There is a basal polytomy consisting of four clades: Ornitholestes, Compsognathidae, Ornithomimosauria, and Maniraptora (i.e., the clade of all taxa more closely related to birds than to Ornithomimus: [S52]). Maniraptora—the clade defined as all taxa closer to birds than to Ornithomimus—is comprised in the present study of Alvarezsauroidea, Therizinosauroidea, Oviraptorosauria, and Paraves. This clade is supported by a Bremer value of 2 but a jackknife percentage of less than 50%. The clade consisting of Oviraptorosauria and Paraves is supported by a Bremer value of 1 and a jackknife percentage of less than 50%. Paraves—consisting of dromaeosaurids, troodontids, and avialans—is also poorly supported, as it also has a Bremer value of 1 and a jackknife of less than 50%.
It must be stated, however, that the scansoriopterygid + oviraptorosaur clade is poorly supported (Bremer support of 1, jackknife percentage of less than 50%).
An Archaeopteryx-like theropod from China and the origin of Avialae
Xing Xu1,2, Hailu You3 , Kai Du4 & Fenglu Han2
It should be noted that our phylogenetic hypothesis is only weakly supported by the available data. Bremer support and bootstrap values for the recovered coelurosaurian subclades are, in general, low, and a bootstrap value less than 50% and a Bremer support value of 2 are obtained for a monophyletic Deinonychosauria including the Archaeopterygidae
We ran Bremer support and bootstrap analyses on the data matrix, using TNT with all default settings except that 1000 replications were used. Bremer support values for the recovered clades are indicated on Figure S8, and only clades with bootstrap values greater than 50% are shown in Figure S9. It is notable that only a few clades meet this criterion in the present analysis.Figure S9:
the authors and others have noted, low support values indicate that many branches near the origin of birds remain unstable 1, 2, 4 and 5.