Reproducibility of results in phylogenetic analysis of mollusks: A reanalysis of the Taylor, Kantor, and Sysoev (1993) data set for conoidean gastropods

Abstract

Reanalysis of the Taylor, Kantor, and Sysoev (1993) data set on conoidean gastropods failed to reproduce their results. Taylor et al. found more than 900 trees of length 189; reanalysis yielded 32.700 trees of length 187. The number of trees they found was limited by the memory available on the computer used for the analysis. The Taylor et al. consensus tree omitted the stated outgroup Benthobia (Pseudolividae); reanalysis including the outgroup yielded 3,149 trees of length 193, in all of which Benthobia fell within the ingroup. Strict and majority-rule consensus trees differed considerably in topology from those with Benthobia excluded. Reanalysis excluding the hypothetical ancestor, whose character states Taylor et al. determined in part by ingroup analysis, yielded additional topologies of consensus trees. Only eight of 38 clades in the Taylor et al. tree appeared in all three strict consensus trees; 17 clades were not supported by any of the majority rule consensus trees. All three majority-rule consensus trees did support the transfer to Conidae by Taylor et al. of the turrid subfamilies Clathurellinae, Conorbinae, Oenopotinae, Mangeliinae, Daphnellinae, and Taraninae. This clade, however, did not appear in two of the strict consensus trees, so support for it is equivocal. Additional problems with the analysis include incorrect character mappings, use of characters primarily from one organ system, conflicts between text and data matrix, choice of taxa, and inclusion of data from taxa not included in the cladistic analysis in formulating the classification. The Taylor et al. data set does not support strong inferences about conoidean phylogeny, and there is not yet convincing evidence for abandoning the traditional classification of the group. Nonetheless, their data are an immensely valuable contribution to be built on as information about conoidean taxa, characters, organ systems, and outgroups accumulates.