摘要:

AbstractAbsolute criteria for evaluating cladistic analyses are useful, not only because cladistic algorithms impose structure, but also because applications of cladistic results demand some assessment of the degree of corroboration of the cladogram. Here, a means of quantitative evaluation is presented based on tree length. The length of the most‐parsimonious tree reflects the degree to which the observed characters co‐vary such that a single tree topology can explain shared character states among the taxa. This “cladistic covariation” can be quantified by comparing the length of the most parsimonious tree for the observed data set to that found for data sets with random covariation of characters. A random data set is defined as one in which the original number of characters and their character states are maintained, but for each character, the states are randomly reassigned to the taxa. The cladistic permutation tail probability, PTP, is defined as the estimate of the proportion of times that a tree can be found as short or shorter than the original tree. Significant cladistic covariation exists if the PTP is less than a prescribed value, for example, 0.05. In case studies based on molecular and morphological data sets, application of the PTP shows that:1In the comparison of four different molecular data sets for orders of mammals, the sequence data set for alpha hemoglobin does not have significant cladistic covariation, while that for alpha crystallin is highly significant. However, when each data set was reduced to the 11 common taxa in order to standardize comparison, reduced levels of cladistic covariation, with no clear superiority of the alpha crystallin data, were found. Morphological data for these 11 taxa had a highly significant PTP, producing a tree roughly congruent with those for the three molecular sets with marginal or significant PTP values. Merging of all data sets, with the exclusion of the poorly structured alpha hemoglobin data, produced a data set with a significant PTP, and provides an estimate of the phylogenetic relationships among these 11 orders of mammals.2In an analysis of lactalbumin and lysozyme DNA sequence data for four taxa, purine‐pyrimidine coding yields a data set with significant cladistic covariation, while other codings fail. The data for codon position 3 taken alone exhibit the strongest cladistic covariation.3A data set based on flavonoids in taxa ofPolygonuminitially yields a significant PTP; however, deletion of identically scored taxa leaves no significant cladistic covariation.4For mitochondrial DNA data on population genome types for four species of the crested newt, there is significant cladistic covariation for the set of all genome types, and among the five mtDNA genome types within one of the species. However, a conditional PTP test that assumes species monophyly shows that no significant cladistic covariation exists among the fur species for these data.5In an application of the test to a group of freshwater insects, as preliminary to biological monitoring, individual subsets of the taxonomic data representing larval, pupal, and adult stages had non‐significant PTPs, while the complete data set showed significant cladisti

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1991.tb00020.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractA data matrix of 32 characters, with a total of 132 character states and 48 terminal taxa of phacopid trilobites, was analysed using parsimony. The 108 most parsimonious trees have a length of 301 steps and a consistency index of 0.29. Two major clades were found, one including species referred toAcernaspisand one with species referred toAnanaspis, Paciphacops, Viaphacops, andPhacops. Most homoplasy occurs between the major clades of the trees, rather than within them. The major clades were also analysed separately, resulting in trees with significantly higher consistency indices. We redefine the following supraspecific taxa to make them monophyletic:Acernaspis, Ananaspis, andPaciphacops. In addition,Kainops, new genus, is described for a clade consisting of six taxa previously assigned toAnanaspisandPaciphacops. The evolutionary pattern resulting from our cladogram is compared with the approaches of Campbell and Eldredge, and it is argued that some of the assumptions made by these authors regarding the phylogeny of the group are not valid. The biogeography of the group was also analysed. It is found that phacopids from the Ludlow and older strata are distributed globally, with an emphasis, perhaps due to a large number of suitable localities, on Northern Europe. However, the lineage of phacopines leading up toPhacopsis, with some slight exceptions, basically confined to the United States, being entirely absent in Northern Europe. The main phacopine lineage does not re‐establish itself geographically until the middle Devonian. Finally, we analysed the evidence for polymorphism in phacopid trilobites, and reject this hypothesis on the basis of stratigraphy and the present cladogra

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1991.tb00021.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1991.tb00022.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractArchie (1990) prefers his “homoplasy excess ratio” HER to Farris' (1989)1ensemble retention indexR. HER, he writes, lacksR's defects:R's minimum is not zero, and varies with number of terminals or characters.HER has those defects. Archie has misunderstood the permutation method on which HER rests, and mistaken the properties ofRas well. After explaining those points, I describe other permutation‐based indices and briefly consider their utility. These provide relative measures of congruence among the characters of the data; one corresponds to a significance

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1991.tb00023.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1991.tb00024.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Book reviews in this article:Phyla, phylogeny and fantasyWonderful life. The Burgess Shale and the nature of historyStephen J. Gould.Wonderful life. The Burgess Shale and the nature of history.—Stephen Jay Goul

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1991.tb00025.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0748-3007    

DOI:10.1111/j.1096-0031.1991.tb00027.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY