摘要:

Abstract—Because they are designed to produced just one tree, neighbor‐joining programs can obscure ambiguities in data. Ambiguities can be uncovered by resampling, but existing neighbor‐joining programs may give misleading bootstrap frequencies because they do not suppress zero‐length branches and/or are sensitive to the order of terminals in the data. A new procedure, parsimony jackknifing, overcomes these problems while running hundreds of times faster than existing programs for neighbor‐joining bootstrapping. For analysis of large matrices, parsimony jackknifing is hundreds of thousands of times faster than extensive branch‐swapping, yet is better able to screen out poorly‐sup

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1996.tb00196.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract—A cladistic analysis of the South American grasshopper generaScotussaandLeiotettixwas performed in order to test the monophyly of these genera.Eurotettix, Chlorusand theDichroplus bergispecies group were included as terminal taxa. The genusAtrachelacriswas used to root the tree. Twenty‐nine characters from external morphology, male genitalia and female ovipositor were used in the analysis. In order to test for association between the structural change that occurred in the ovipositor valves ofScotussaand the functional change of the oviposition habits, the data matrix was partitioned and two analyses were performed. Characters from the female ovipositor were excluded from the data set used in the first analysis and another analysis was performed where all the characters were included in the analysis. Information on oviposition habits was then mapped on the cladogram, to determine the transformation for performance. Both analyses yielded only one most parsimonious tree and produced congruent results, confirming the monophyly ofLeiotettixandScotussaand corroborating their close relationship. Characters from the female ovipositor valves were informative not only at the species level but also at higher levels in the cladogram. The results also support the hypothesis of association between the structural change that occurred in the ovipositor valves ofScotussawith the functional change in the oviposition habits. However, this association did not seem to be correlated with the adaptive radiation in the ge

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1996.tb00197.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract—The “soft” assumption attributes polytomies to lack of data, not simultaneous cladogenesis (the “hard” assumption). Most systematists prefer the first interpretation, but most parsimony programs implicitly use the second. Results can thus be inconsistent with initial assumptions. Under certain circumstances that seem especially typical for large data sets treating higher taxa, it may be valid to eliminate both compatible and incompatible polytomous trees from consideration. Consistent treatment of soft polytomies can reduce the ambiguity of cladistic solutions and improve the resolution, and testability, of phylogenetic h

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1996.tb00198.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1996.tb00199.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1996.tb00200.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

The effect of uninformative characters on the “significance levels” obtained by bootstrapping in cladistic analysis is investigated empirically. Twenty‐eight data sets from Platnick's benchmarks are analysed with Siddall's Random Cladistics bootstrapping module and Farris’Hennig86 program, using 1000 replicates and exact calculations. Contrary to the assurances of Harshman, inclusion of autapomorphies in a matrix commonly leads to a loss of “sign

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1996.tb00201.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY