Validating a molecular clock for nudibranchs: No fossils to the rescue

Time-calibrated phylogenies are typically reconstructed with fossil information but for soft-bodied marine invertebrates that lack hard parts, a fossil record is lacking. In these cases, biogeographic calibrations or rates of divergence for related taxa are often used. Although nudibranch phylogenies have advanced with the input of molecular data, no study has derived a divergence rate for this diverse group of invertebrates. Here, we use an updated closure date for the Isthmus of Panama (2.8 ma) to derive the first divergence rates for chromodorid nudibranchs using multi-gene data from a geminate pair with broad phylogeographic sampling. Examining the species Chromolaichma sedna (Marcus & Marcus, 1967), we uncover deep divergences among eastern Pacific and western Atlantic clades and we erect a new species designation for the latter (Chromolaichma hemera sp. nov.). Next, we discover extensive phylogeographic structure within C. hemera sp. nov. sensu lato, thereby refuting the hypot..., , , # Validating a molecular clock for nudibranchs – no fossils to the rescue

This dataset contains COI, 16S and ANT gene alignments.

## Description of the data and file structure

This dataset contains COI, 16S and ANT gene alignments. The naming convention used for each sequence is \"Sample Field ID \_RegistrationNumber\", and this data can be found in Table 1 of the manuscript.

## Sharing/Access information

All genetic data is available on GenBank and accession numbers are listed in Table 1 of the manuscript.

## Code/Software

There is no custom code needed to analyze these files. The following programs were used to process and/or analyze data: Geneious, MAFFT, RAxML, ASAP, bPTP, R (pegas package).