DOI: 10.6084/m9.figshare.29577563.v1
title: The lady of the rings: integrative systematics of <i>Nanuca</i> Er. Marcus, 1957 (Mollusca: Nudibranchia: Myrrhinidae) reveals a hidden diversity

description: <b>Abstract</b>Myrrhinidae are one of the most species-rich families of aeolid nudibranchs. The genus <i>Nanuca</i> comprises a single species, <i>N. sebastiani</i>, which has a wide geographical distribution along the tropical Western Atlantic. The taxonomy of <i>Nanuca</i> has not been thoroughly studied, and its relationship with the genus <i>Dondice</i> is unclear. Using newly generated sequences, we created the most comprehensive dataset to date for studying evolution of Myrrhinidae. We employed an integrative approach combining phylogenetic analyses and species’ delimitation methods (ABGD, ASAP, GMYC, PTP) with mitochondrial (<i>COI</i>, 16S) and nuclear (28S LSU D1-D2) genes, as well as morphological and biogeographical evidence. Our analysis recovered the six genera of Myrrhinidae as monophyletic, reinforcing <i>Dondice</i> and <i>Nanuca</i> as distinct taxa. Molecular phylogenetics, species’ delimitation, and morphological data support the existence of six species of <i>Nanuca</i>: the polymorphic <i>N. sebastiani</i> and five new pseudocryptic species, <b><i>N. smaugi</i></b><b> sp. nov.</b>, <b><i>N. perolata</i></b><b> sp. nov.</b>, <b><i>N. cahuitaensis</i></b><b> sp. nov.</b>, <b><i>N. alboviridis</i></b><b> sp. nov.</b>, and <b><i>N. leali</i></b><b> sp. nov.</b> Our work sheds light on biogeographic barriers, like the Amazon River plume, and ecological transitions along Florida, the Caribbean Sea, and Brazil as drivers to <i>Nanuca</i> diversification. Our findings highlight the importance of considering nudibranch species’ diversity within an evolutionary context.<b>Description of the data and file structure</b>The current data were used in our phylogenetic, species´ delimitation, molecular distances, haplotype network, and molecular diagnostic character analyses of integrative taxonomy for the nudibranch genus <i>Nanuca</i> in the tropical Western Atlantic.<b>Files</b><b>Supp_File_01_COI_alignment_larger_dataset.fas</b>FASTA alignment of 98 sequences from COI. Alignment length: 657 bp.<b>Supp_File_02_16S_alignment_larger_dataset.fas</b>FASTA alignment of 75 sequences from 16S rRNA. Alignment length: 381 bp.<b>Supp_File_03_COI_alignment_shorter_dataset.fas</b>FASTA alignment of 25 sequences from COI, with one <i>Dondice</i> species included as outgroup. Alignment length: 657 bp.<b>Supp_File_04_28S_LSU_D1-D2_alignment_shorter_dataset.fas</b>FASTA alignment of 16 sequences from 28S LSU D1–D2 and one <i>Dondice</i> outgroup. Alignment length: 940 bp.<b>Supp_File_05_COI_ABGD_and_ASAP.fas</b>FASTA alignment of 17 unique haplotype sequences from COI used in ABGD and ASAP species delimitation analyses. Alignment length: 657 bp.<b>Supp_File_06_COI_GMYC_and_PTP.fas</b>FASTA alignment of 17 unique haplotype sequences from COI, including one <i>Dondice</i> outgroup, used for tree-based species delimitation (GMYC and PTP). Alignment length: 680 bp.<b>Supp_File_07_28S_LSU_D1-D2_ABGD_and_ASAP.fas</b>FASTA alignment of four unique haplotype sequences from 28S LSU D1–D2 used in ABGD and ASAP analyses. The alignment also includes duplicates of unique haplotypes to enable species delimitation methods. Alignment length: 951 bp.<b>Supp_File_08_28S_LSU_D1-D2_GMYC_and_PTP.fas</b>FASTA alignment of four unique haplotype sequences from 28S LSU D1–D2 and a <i>Dondice</i> outgroup, used for tree-based species delimitation (GMYC and PTP). The alignment also includes duplicates of unique haplotypes to enable species delimitation methods. Alignment length: 956 bp.<b>Supp_File_09_COI_network.nex</b>NEXUS file with 24 sequences from COI and associated trait data, formatted for haplotype network analysis in PopArt.<br>