Toward an atlas of Salish Sea biodiversity: the flora and fauna of Galiano Island, British Columbia, Canada. Part I. Marine zoology.

Background: Based on records dating from 1859 to 2021, we provide an overview of the marine animal diversity reported for Galiano Island, British Columbia, Canada. More than 650 taxa are represented by 20,000 species occurrence records in this curated dataset, which includes dive records documented through the Pacific Marine Life Surveys, museum voucher specimens, ecological data and crowd-sourced observations from the BC Cetacean Sightings Network and iNaturalist.

New Information: We describe Galiano Island's marine animal diversity in relation to the Salish Sea's overall biodiversity and quantify the proportional contributions of different types of sampling effort to our current local knowledge.

Three new species of the genus Dendronotus from Japan and Russia (Mollusca, Nudibranchia).

Three new species of the genus Dendronotus are described from the North Pacific waters of Japan and Russia. For the first time since 1949, three new species, D. jamsteci sp.

Fine-scale species delimitation: speciation in process and periodic patterns in nudibranch diversity.

Using the nudibranch genus as a model, ongoing speciation is demonstrated, as well as how periodic-like patterns in colouration can be included in an integrated method of fine-scale species delimitation. By combining several methods, including BPP analysis and the study of molecular, morphological, and ecological data from a large number of specimens within a broad geographic range from northern Europe to the Mediterranean, five species are recognised within the genus , reviewed here for the first time. Two new species from the southwestern coast of Sweden are described, and Evidence is provided of a recent speciation process between the two closely related, yet separate, species which inhabit the same geographic localities but demonstrate strict water depth differentiation, with one species inhabiting the shallow brackish top layer above the halocline and the other species inhabiting the underlying saltier water.

Multiple paedomorphic lineages of soft-substrate burrowing invertebrates: parallels in the origin of Xenocratena and Xenoturbella.

Paedomorphosis is an important evolutionary force. It has previously been suggested that a soft-substrate sediment-dwelling (infaunal) environment facilitates paedomorphic evolution in marine invertebrates. However, until recently this proposal was never rigorously tested with robust phylogeny and broad taxon selection.

Multilevel fine-scale diversity challenges the 'cryptic species' concept.

'Cryptic' species are an emerging biological problem that is broadly discussed in the present study. Recently, a cryptic species definition was suggested for those species which manifest low morphological, but considerable genetic, disparity. As a case study we present unique material from a charismatic group of nudibranch molluscs of the genus Trinchesia from European waters to reveal three new species and demonstrate that they show a dual nature: on one hand, they can be considered a 'cryptic' species complex due to their overall similarity, but on the other hand, stable morphological differences as well as molecular differences are demonstrated for every species in that complex.

The genus Zelentia is an amphi-boreal taxon expanded to include three new species from the North Pacific and Atlantic oceans (Gastropoda: Nudibranchia: Trinchesiidae).

The taxonomy of Zelentia Korshunova, Martynov Picton, 2017, a genus of aeolidacean nudibranchs recently separated from Trinchesia Ihering, 1879, is reviewed. Using previous and novel data, including the defining morphological characters of a supplementary gland inserted into the penis, which is also armed with stylet, it is demonstrated that the genus Zelentia is a well-established amphi-boreal taxon. A phylogenetic tree and haplotype network for species of the genus Zelentia are provided.

Corrigenda: Polyphyly of the traditional family Flabellinidae affects a major group of Nudibranchia: aeolidacean taxonomic reassessment with descriptions of several new families, genera, and species (Mollusca, Gastropoda). https://doi.org/10.3897/zookeys.717.21885.

[This corrects the article DOI: 10.3897/zookeys.717.

Polyphyly of the traditional family Flabellinidae affects a major group of Nudibranchia: aeolidacean taxonomic reassessment with descriptions of several new families, genera, and species (Mollusca, Gastropoda).

The Flabellinidae, a heterogeneous assembly of supposedly plesiomorphic to very derived sea slug groups, have not yet been addressed by integrative studies. Here novel material of rarely seen Arctic taxa as well as North Atlantic, North and South Pacific, and tropical Indo-West Pacific flabellinid species is investigated morpho-anatomically and with multi-locus markers (partial COI, 16S rDNA, 28S rDNA and H3) which were generated and analysed in a comprehensive aeolid taxon sampling. It was found that the current family Flabellinidae is polyphyletic and its phylogeny and taxonomic patterns cannot be understood without considering members from all the Aeolidacean families and, based on a robust phylogenetic hypothesis, morpho-anatomical evolution of aeolids is more complex than suspected in earlier works and requires reclassification of the taxon.

Two new species and a remarkable record of the genus from the North Pacific and Arctic oceans (Nudibranchia).

Two new species of the nudibranch genus , and , are described from the Arctic and North Pacific oceans respectively, based on morphological and molecular data, and the North Pacific is revealed to be a species complex. The species is described from the northwestern Pacific (Kamchatka) differing from the northeastern Pacific by molecular and morphological data. The synonymy of with is confirmed by analysis of their original descriptions.