This article comprise the data related to the research article (Møller et al., 2016) [1], and makes it possible to explore and reproduce the topologies that allowed [1] to infer the relationship between the families Bythitidae and Dinematichthyidae. The supplementary data holds nexus-input files for the Bayesian analysis and the '.xml'-input files - with and without nucleotide data - that are used in the fossil-calibrated phylogenetic analysis with a relaxed clock model. The resulting topologies are provided as '.new'-files together with a characters matrix file for traits to trace across the inferred phylogenies.