Reassessing the role of morphology in bryophyte phylogenetics: combined data improves phylogenetic inference despite character conflict

FLORES, JORGE R.; HYVÖNEN, JAAKKO; SUÁREZ, GUILLERMO M.

MOLECULAR PHYLOGENETICS AND EVOLUTION

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2019 vol. 143

1055-7903

Morphological data has gained renewed attention and has been shown to be crucial in clarifying the phylogeneticrelationship in a wide range of taxa. In the last decades, phylogenetic analyses of sequence-level data have radicallymodified the systematic schemes within bryophytes (early non-vascular land plants) and have revealed a widespreadpattern of conflict with morphology-based classifications. Yet, a comprehensive evaluation of character conflict was notperformed in the context of combined matrices. In this study, we evaluate the impact of morphology on bryophytephylogeny following a total-evidence approach across 10 published matrices. The analysed matrices spanned a widerange of bryophytes, taxonomic levels, gene sampling and number of morphological characters and taxa. Data conflictwas addressed by measuring: (i) the topological congruence between individual partitions, (ii) changes in supportvalues of the combined data relative to the molecular partition and (iii) clade stability. The association between thesemeasures and the number of morphological characters per taxon (Nc/T ratio) and the proportion of non-fixedcharacters (i.e., inapplicable, polymorphic and missing data) was explored. In the individual partition analyses, theNc/T ratio correlated positively with the topological congruence in six to seven datasets depending on the weightingscheme. The proportion of non-fixed cells had a minor influence on congruence between data partitions. Among thedatasets improving congruence between data types, morphology consisted of a different number of characters or nonfixed data. Hence, suggesting that different taxa have specific responses to morphology. Combined data revealed that,despite the low congruence values between partitions, integrating data types improves support values and stability.However, while non-fixed data had no negative effect on support values, stability was reduced as the proportion ofnon-fixed cells increased. Nc/T ratio was negatively associated with support values and it showed ambiguousresponses in stability evaluations. Overall, the results indicate that adding morphology may contribute to the inferenceof phylogenetic relationships of bryophytes despite character conflict. Our findings suggest that merely comparing (a)morphology-based classifications with molecular phylogenies or (b) the outcome from individual data partitions canmisestimate data conflict. These findings imply that analyses of combined data may provide conservative assessmentsof data conflict and, eventually, lead to an improved sampling of morphological characters in large-scale analyses ofbryophytes.