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Title: Competing hypotheses and character conflict in palaeontological phylogenetics
Author: Corfe, Ian J.
ISNI:       0000 0004 2674 9802
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2006
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What happens in the case where more than one morphologic dataset is used to generate hypotheses of phylogeny for fossil taxa? Sometimes the different investigations produce congruent results, but more often than not, a degree of conflict between the relationships hypothesised is observed. Little work has been carried out on quantifying this conflict, and still less on discerning the source(s) and cause(s) of such conflict, especially for morphological (as opposed to molecular) data. As evolutionary studies are critically dependent upon the accuracy of phylogenies, finding the cause of phylogenetic conflict becomes a keystone of accurate evolutionary biology. Here, two case studies are examined in which conflict is identified between competing morphological, palaeontological phylogenetic hypotheses. The first, investigating the relationships of sauropod dinosaurs, focuses on two more or less independently derived datasets. By quantifying and identifying sources of statistically significant conflict between the phylogenetic hypotheses produced, it highlights priority areas for further study in order to produce more congruent estimates of relationship. It is shown that congruence has increased through time between competing sauropod phylogenies. By following a stepped methodology, increasingly more detail can be resolved regarding the presence, statistical significance, source(s) and cause(s) of the remaining conflict. The second involves a very small number of rescorings and recodings to an existing dataset based on a recently described specimen of Archaeopteryx. These result in a dramatically different phylogenetic hypothesis - namely, the polyphyly of Aves. It is shown that this is not statistically significantly betterer supported than the original hypothesis of a monophyletic Aves, and that relationshij general within coelurosaurian dinosaurs are very uncertain, and subject to change with extremely minor differences in character scoring.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available