Match and mismatch of morphological and molecular phylogenies: causes, implications, and new light on cladistics

Cohen, B. L. (2018) Match and mismatch of morphological and molecular phylogenies: causes, implications, and new light on cladistics. Zoological Journal of the Linnean Society, 184(2), pp. 516-527. (doi: 10.1093/zoolinnean/zly004)

Abstract

Established methods of exploratory data analysis reveal conflicts in morphological data from rhynchonellide brachiopods, conflicts that result in mismatches between morphological, combined, and molecular phylogenies. Consideration of the mismatches uncovers several findings of general applicability: causes of conflict include the inherent genealogical deficit of comparative morphology, and genetic signal erosion caused by genome remodelling. Because of genetic signal erosion, cladistic analysis cannot be used safely on taxa whose remote ancestors diverged in deep time. In theory, if not practice, morphological-molecular conflict may be avoided by use of genetically validated characters. The preliminary (prior) classification of the organisms concerned is a hitherto-overlooked first step of cladistic analysis; its integral roles are to enable homology hypotheses, and at least partly to determine cladistic results through classification bias. Thus hitherto, cladistics has been misunderstood and misrepresented; many reported taxon relationships may have been determined more by the prior classification than by the supporting characters. If the prior classification is artificial and does not accurately mirror evolutionary history, morphological and molecular phylogeny mismatches will register as spurious homoplasy. To avoid logical circularity in cladistic analysis there must be clear separation of input (taxon descriptions) from output (clades). This requirement rules out PhyloCode-like approaches to systematics if they allow (named) output of cladistic analysis to serve as the input to further such analyses.

• Item Type: Articles
• Keywords: Animal science and zoology, ecology, evolution, behavior and systematics
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Cohen, Dr Bernard
• Authors: Cohen, B. L.
• College/School: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Journal Name: Zoological Journal of the Linnean Society
• Publisher: Oxford University Press
• ISSN: 0024-4082
• ISSN (Online): 1096-3642
• Published Online: 29 March 2018