New mitogenomes of Runcinidae and Facelinidae: two understudied heterobranch families (Mollusca: Gastropoda).

Here, we present the mitochondrial sequences of two sea slugs (Heterobranchia): Runcina aurata and Facelina auriculata, the latter being the type species of the family. The mitochondrial genomes are 14,282 and 14,171bp in length, respectively, with a complete set of 13 PCGs, 2 rRNAs, and 22 tRNAs. None of the mitogenomes show gene reorganization, keeping the standard mitogenomic structure of Heterobranchia. Nucleotide composition differs significantly between them, with R. aurata showing the most AT-rich mitogenome (25.7% GC content) reported to date in Heterobranchia, and F. auriculata showing a rich GC content (35%) compared with other heterobranch mitochondrial genomes.

A combined phylogenetic strategy illuminates the evolution of Goniodorididae nudibranchs (Mollusca, Gastropoda, Heterobranchia).

Goniodorididae is a family of small dorid nudibranchs distributed worldwide that feed on entoprocts, ascidians, and bryozoans. The evolutionary relationships between its taxa have been uncertain due to the limited taxa available for phylogenetic analyses; some genera being paraphyletic. The family includes a remarkable number of synonymized genera in which the species richness is unequally distributed, while some genera have dozens of species others are monospecific. Some clades are very uniform morphologically while others are considered highly variable. To increase backbone phylogenetic resolution a target enrichment approach of ultra-conserved elements was aimed at representative Goniodorididae species for the first time. Additionally, we increase species representation by including mitochondrial markers cytochrome c oxidase subunit I and ribosomal RNA 16S as well as nuclear Histone 3 and ribosomal RNA 18S from 109 Goniodorididae species, out of approximately 160 currently valid species. Maximum likelihood and Bayesian inference analyses were performed to infer the phylogeny of the family. As a result, two subfamilies and eleven genera were elucidated. The synonymized genera Bermudella, Cargoa, and Ceratodoris are here resurrected and a new genus, Naisdoris gen. nov., is described. The clades included taxa with shared prey preference, showing that trophic behavior could have driven species evolution and morphological uniqueness within the family Goniodorididae.

What is really out there? Review of the genus Okenia Menke, 1830 (Nudibranchia: Goniodorididae) in the Mediterranean Sea with description of two new species.

The precise number of Okenia taxa inhabiting the Mediterranean Sea, as well as their general taxonomy, varies according to different specialists. So far, eight valid species have been reported from the area: Okenia aspersa (Alder & Hancock, 1845), Okenia cupella (Vogel & Schultz, 1970), Okenia elegans (Leuckart, 1828), Okenia hispanica Valdés & Ortea, 1995, Okenia impexa Er. Marcus, 1957, Okenia leachii (Alder & Hancock, 1854), Okenia mediterranea (Ihering, 1886), and Okenia zoobotryon (Smallwood, 1910). Of these, only three (O. elegans, O. hispanica, and O. mediterranea) have their type localities in the Mediterranean Sea, whereas the others were described from different biogeographic areas and later included in the Mediterranean biota. We carried out a review on Mediterranean Okenia species through an integrative approach, based on a wide literature search and a morphological and molecular analysis of available type material and samples collected recently. The present study confirmed the presence of O. aspersa, O. elegans, O. hispanica, and O. mediterranea in the Mediterranean Sea, although leaving remaining questions about some of those taxa. The distribution of O. cupella, O. impexa, and O. zoobotryon is limited to the western Atlantic, and of O. leachii to the eastern Atlantic. All specimens previously identified as O. cupella, O. impexa, and O. zoobotryon by different authors in the Mediterranean Sea were repeatedly misidentified. Thus, we describe Okenia problematica sp. nov. and Okenia longiductis sp. nov., from the "Mediterranean" Okenia cupella/impexa and O. zoobotryon. We also consider here Okenia pusilla Sordi, 1974 a nomen dubium and include a redescription of the holotype of O. cupella. A molecular phylogeny, including all the sequenced Okenia species, was performed in order to evaluate the evolutionary relationships of the newly described species with the other congeneric taxa.

Astonishing diversity revealed: an annotated and illustrated inventory of Nudipleura (Gastropoda: Heterobranchia) from Mozambique.

This paper provides the first comprehensive annotated and illustrated inventory of Nudipleura from Mozambique. A total of 267 species are recorded, including 61 putative new species, documented over a period of seven years from several localities along the coast. At least 20 species need further investigation through molecular and taxomic analysis. Of the 186 confirmed described species, 118 are new records for the Mozambican fauna. Sampling was carried in tidal reefs and depths up to 60m on the subtropical and tropical coast of Mozambique. The most representative families were Chromodorididae (69 species), Discodorididae (30 species), Facelinidae (23 species) and Phyllididae (16 species). Nevertheless, a vast area of Mozambique remains unexplored, thus it is likely that the species documented here represent only a fraction of the true Nudipleura diversity of the country.

Review of Baeolidia, the largest genus of Aeolidiidae (Mollusca: Nudibranchia), with the description of five new species.

This paper discusses the systematics of the aeolid genus Baeolidia Bergh, 1888. To date, this monophyletic genus is the most diverse within Aeolidiidae with sixteen valid species. Excluding Baeolidia cryoporos Bouchet, 1977, the genus is restricted to the Indo-Pacific and Eastern Pacific. Species of Baeolidia show a huge intrageneric variability in several morphological characters. Only oral glands, if present, may distinguish Baeolidia from other aeolidiids genera. Aeolidiella occidentalis Bergh, 1875, Aeolidiella faustina Bergh, 1900 and Spurilla orientalis Bergh, 1905 are transferred to Baeolidia but they are considered nomina dubia. Five new species, Baeolidia rieae sp. nov., Baeolidia variabilis sp. nov., Baeolidia lunaris sp. nov., Baeolidia gracilis sp. nov. and Baeolidia scottjohnsoni sp. nov. are described.

Going further on an intricate and challenging group of nudibranchs: description of five novel species and a more complete molecular phylogeny of the subfamily Nembrothinae (Polyceridae).

Nembrothinae is a colourful subfamily of nudibranch polycerids, which despite its large size and striking appearance, needs to be more thoroughly studied. The available scientific information about this subfamily is very recent, and pictures of living undescribed species become available every day. Nevertheless, the lack of associated material for morphological, anatomical, and molecular analysis results in scarce additional studies. In this paper, five novel species are described: Roboastra ernsti sp. nov., Roboastra nikolasi sp. nov., Tambja brasiliensis sp. nov., Tambja crioula sp. nov., and Tambja kava sp. nov. In addition, Tambja divae (Marcus, 1958), a species previously known only from the original description, is redescribed and additional data and comments on Tambja cf. amakusana Baba, 1987 and Tambja marbellensis Schick and Cervera, 1998 are provided. Molecular data (H3, COI and 16S genes) for all these novel species and some additional ones were obtained and included in a previous molecular database. Maximum-likelihood, maximum-parsimony and Bayesian analyses were carried out. The phylogeny presented here has revealed Nembrothinae to be an intricate and challenging group of nudibranchs to study. Intermediate missing species seem to be critical to understanding the evolutionary relationships within this group.

A tale that morphology fails to tell: a molecular phylogeny of Aeolidiidae (Aeolidida, Nudibranchia, Gastropoda).

Aeolidida is one of the largest clades of nudibranchs with at least 560 known species. However, its systematics has not been studied in a comprehensive manner. Phylogenetic analyses of larger clades such as Nudibranchia or Cladobranchia have usually included a poor sample of aeolids. Furthermore, phylogenetic studies at the family or generic level in Aeolidida are a few and far between. The first molecular phylogeny of the aeolid family Aeolidiidae is presented here. This study, the most comprehensive for Aeolidida to date, uses new sequences of two mitochondrial (COI and 16S) genes and one nuclear gene (H3). 251 specimens from members of seven families of Aeolidida, including 39 species of Aeolidiidae were studied. Excluding Pleurolidia juliae, Aeolidiidae is monophyletic. Our results resolve the systematic relationships within the Aeolidiidae at a generic level, requiring changes in the systematics of this family. Spurilla, Anteaeolidiella, Limenandra and Aeolidia are well-supported and monophyletic clades. Aeolidiella stephanieae is transferred to Berghia and Aeolidiopsis ransoni and Spurilla salaamica to Baeolidia, to maintain the monophyletic lineages reflected in this study. The systematics of Cerberilla remains unclear. Some species earlier attributed to Aeolidiella are now grouped in a previously unnamed clade that we designate as Bulbaeolidia gen. nov.

The first molecular phylogeny of cladobranchian opisthobranchs (Mollusca, Gastropoda, Nudibranchia).

The first molecular phylogeny is presented for the highly diverse, opisthobranch molluscan Cladobranchia. This study, the most comprehensive for Cladobranchia to date, used new sequences of two mitochondrial and one nuclear genes for 95 specimens from 22 families and 38 genera with a species of Pleurobranchoidea as outgroup. Although our results do not resolve all the relationships within the Cladobranchia, there are significant findings that have implications for the systematics of the Cladobranchia. Cladobranchia represents a monophyletic group within the Nudibranchia with the exception of a clade containing species of Melibe. These species share a deletion of four codons in the COI gene that may account for their strong divergence from the remainder of the Cladobranchia. Bornellidae is the sister group to the rest of Cladobranchia, but this relationship is weakly supported. A series of well-supported clades within Cladobranchia show little structure as to their relationships to each other in the current analysis. The relationships of Tethys and Hancockidae to other Cladobranchia remain unresolved. Pseudobornella orientalis is here transferred to Dendronotus as D. orientalis. With this systematic change Bornellidae and Dendronotidae are now monophyletic. Lomanotus appears as the sister group to a monophyletic Aeolidida, but this relationship is not strongly supported. Scyllaeidae is monophyletic in this study with Scyllaea being sister taxon to Notobryon. The Proctonotidae are monophyletic and are clearly nested in the Cladobranchia. Dotoidae is monophyletic when Pinufius is included in this clade. Doriodomorpha is sister taxon to the Arminidae. Within Arminidae, Dermatobranchus and Armina, as they are presently constructed, are not monophyletic. There is an interesting potential sister group relationship between Dirona albolineata and Lemina millecra that requires additional exploration with expanded taxon sampling. In this study, Marianina rosea is nested within Tritoniidae, thus we consider Aranucidae, and its synonym Marianinidae, as a junior synonym of Tritoniidae to preserve the monophyly of Tritoniidae.

Phylogenetic relationships of Nembrothinae (Mollusca: Doridacea: Polyceridae) inferred from morphology and mitochondrial DNA.

Within the Polyceridae, Nembrothinae includes some of the most striking and conspicuous sea slugs known, although several features of their biology and phylogenetic relationships remain unknown. This paper reports a phylogenetic analysis based on partial sequences of two mitochondrial genes (cytochrome c oxidase subunit I and 16S rRNA) and morphology for most species included in Nembrothinae. Our phylogenetic reconstructions using both molecular and combined morphological and molecular data support the taxonomic splitting of Nembrothinae into several taxa. Excluding one species (Tambja tentaculata), the monophyly of Roboastra was supported by all the phylogenetic analyses of the combined molecular data. Nembrotha was monophyletic both in the morphological and molecular analyses, always with high support. However, Tambja was recovered as para- or polyphyletic, depending on the analysis performed. Our study also rejects the monophyly of "phanerobranch" dorids based on molecular data.