The first consolidation of morphological, molecular, and phylogeographic data for the finely differentiated genus Diaphoreolis (Nudibranchia: Trinchesiidae)

We demonstrate the application of the multilevel organismal diversity approach using the example of the nudibranch trinchesiid genus Diaphoreolis. For the first time, fine-scale morphological, genetic, and phylogeographic data are presented for all known species of the genus Diaphoreolis. One of the significant results of the present study and analysis is that the species D. stipata (Alder and Hancock, 1843) comb. nov., originally described from the North Atlantic and reinstated here, is revealed to be a sister species to the new NW Pacific species Diaphoreolis zvezda sp. nov. described from the Kuril Islands. Hidden diversity within the traditional taxon D. “ viridis” is revealed both in the North Pacific and the North Atlantic. A new subspecies, D. viridis emeraldi subsp. nov., is established for the Canadian and USA NE Pacific forms, and both morphological and molecular data are presented for the separate NW Pacific species D. midori. The present study combines practical results from a particular taxonomic group (nudibranchs) with generally important considerations for the expanding practice of uniting fine-scale morphological and molecular data.