The Proceedings of the Eighth International Conference on Creationism (2018)

it is worth pointing out that two of our datasets appear to have been newly constructed and not based on earlier matrices (Ahlberg and Clack 1998; Ruta 2011), and those that did draw on previously published matrices rescored or modified some characters and/or used different character-taxon combinations. Overall, we feel that the matrices we selected are sufficiently different to regard them as independent. A third issue concerns the bootstrapping results. Some of our analyses were characterized by poor bootstrap values, in particular those based on the matrices of Ahlberg and Clack (1998), Sookias et al. (2014) and Clack et al. (2016). However, as Wood (2008b) has pointed out, low bootstrap values should not be taken to imply that the correlations are not significant, but rather that they are highly dependent on a particular character set. This highlights where future research may be needed. Moreover, the fact that we obtained similar results with datasets yielding better bootstrap values bolsters our confidence in the conclusions that we have drawn. Finally, a fourth concern is our removal of outgroups, a procedure that raises the question of whether different results might have been obtained had more of those taxa been retained in our analyses. Our rationale for removing these taxa is that they represented multiple families so different from the Devonian taxa in which we were particularly interested, that their presence in our analyses was swamping discontinuities that were otherwise evident among the Devonian forms. However, other analyses could undoubtedly be run with different outgroup selections in order to see whether our results can be replicated. CONCLUSION Our studies reveal statistical evidence of morphological discontinuity between Devonian and Carboniferous tetrapods and the Devonian elpistostegids, which we interpret as evidence of phylogenetic discontinuity and, by implication, separate ancestry. Given that this result was consistent across all six of our datasets, we think that our conclusions are robust and will likely withstand future analyses. However, further studies using other datasets with different combinations of taxa and characters are encouraged. ACKNOWLEDGMENTS We would like to thank the Creation Biology Society for financial assistance and Todd C. Wood for help with drafting the bootstrap plots. We are also grateful to two anonymous reviewers, whose advice and comments greatly improved this paper. REFERENCES Ahlberg, P.E. 1991. Tetrapod or near-tetrapod fossils from the Upper Devonian of Scotland. Nature 354:298-301. Ahlberg, P.E. 1995. Elginerpeton pancheni and the earliest tetrapod clade. 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