Two new species of the Aglajid genus Melanochlamys (Gastropoda: Opisthobranchia)

São descritas duas espécies novas de opistobrânguios aglajídeos do gênero Melanochlamys. M. papillata é proveniente da Tailândia e M. barryi foi coletada apenas em "False Bay", Africa do Sul. Ambas as espécies diferem pronunciadamente de outras congenéricas em detalhes da sua anatomia reprodutiva e na morfologia peniana. A disposição dos órgãos reprodutivos em M. barryi representa o modelo mais primitivo dentro do gênero e fornece dados adicionais para a pesquisa da filogenia da família Aglajidae

Like a bat out of heaven: the phylogeny and diversity of the bat-winged slugs (Heterobranchia: Gastropteridae)

A molecular phylogeny is presented for 25 newly sequenced specimens of Gastropteridae. The present phylogeny was estimated by analysing the nuclear fragment 28S and two mitochondrial fragments cytochrome c oxidase I (COI) and 16S using maximum likelihood and Bayesian analyses. The distinctness of eight new species of Gastropteridae is supported by the molecular phylogeny and by subsequent Automatic Barcode Gap Discovery (ABGD) analysis. Morphological data also support the distinctness of these species. The following species are described here: Gastropteron minutum Ong and Gosliner sp. nov., Gastropteron multo Ong and Gosliner sp. nov., Sagaminopteron multimaculatum Ong and Gosliner sp. nov., Siphopteron vermiculum Ong and Gosliner sp. nov., Siphopteron flavolineatum Ong and Gosliner sp. nov., Siphopteron nakakatuwa Ong and Gosliner sp. nov., Siphopteron makisig Ong and Gosliner sp. nov. and Siphopteron dumbo Ong and Gosliner sp. nov. All of these species, spanning much of the phylogenetic tree of Gastropteridae, are found in a single, highly diverse region of the Philippines, the Verde Island Passage. These data support the hypothesis that this region is an area of high species richness as well as phyletic diversity. This study also supports strong correlation between morphological characters and the molecular phylogeny within the species of Siphopteron. Molecular studies also indicate the distinctness of specimens of Siphopteron quadrispinosum from Hawaii and those from the western Pacific. Western Pacific specimens should be regarded as Siphopteron leah. Siphopteron pohnpei is transferred to Sagaminopteron based on the molecular phylogeny. Other species complexes indicating the presence of geographically separated cryptic species indicate that further detailed study of this group is warranted and that hidden diversity is likely to increase with additional study

Revisión del género indopacífico Nembrotha Bergh, 1877 (Mollusca: Nudibranchia: Polyceridae), con la descripción de dos nuevas especies

Anatomical examination of new material collected from the Indo-Pacific and the review of several collections from around the world allows for the revision of the genus Nembrotha Bergh, 1877. Two new species, Nembrotha rosannulata n. sp. and Nembrotha aurea n. sp., are described. The oldest available name for the genus is Nembrotha nigerrima Bergh, 1877, which was subsequently designated as the type species by O’Donoghue, 1924. The study of the original type material of N. nigerrima confirmed that it is a senior synonym of another name introduced subsequently, Nembrotha kubaryana Bergh, 1877, the name most commonly used for this species. However, according to the provisions of the International Code of Zoological Nomenclature (Article 23.9.1), there is no reason to invalidate the senior name Nembrotha nigerrima, since it has been used as valid after 1899. Nembrotha cristata Bergh, 1877, N. lineolata Bergh, 1905, N. purpureolineata O’Donoghue, 1924, N. livingstonei Allan, 1933, N. megalocera Yonow, 1990 and N. guttata Yonow, 1993, which are poorly known, are redescribed. Nembrotha rutilans (Pruvot-Fol, 1931) is synonymised with N. purpureolineata. Nembrotha yonowae Goethel and Debelius, 1992 is synonymised with N. guttata. The radulae of Nembrotha milleri Gosliner and Behrens, 1997 and N. mullineri Gosliner and Behrens, 1997 are redescribed.El estudio anatómico de nuevo material procedente del Indo-Pacífico así como el examen de diferentes colecciones de todo el mundo ha permitido la revisión del género Nembrotha Bergh, 1877. Se describen dos nuevas especies, Nembrotha rosannulata n. sp. y Nembrotha aurea n. sp. El nombre disponible más antiguo relativo a este género es Nembrotha nigerrima Bergh, 1877, que fue designado subsiguientemente como especie tipo por O’Donoghue, 1924. El estudio del material tipo original de N. nigerrima confirmó que se trata de un sinónimo más antiguo de otro nombre introducido con posterioridad, Nembrotha kubaryana Bergh, 1877, el nombre usado más comúnmente para esta especie. Sin embargo, según lo previsto en el Código Internacional de Nomenclatura Zoológica (Artículo 23.9.1), no hay razón alguna para invalidar el sinónimo más antiguo, Nembrotha nigerrima, ya que este nombre ha sido utilizado como válido después de 1899. Nembrotha cristata Bergh, 1877, N. lineolata Bergh, 1905, N. purpureolineata O’Donoghue, 1924, N. livingstonei Allan, 1933, N. megalocera Yonow, 1990 and N. guttata Yonow, 1993, especies pobremente conocidas, son redescritas. Nembrotha rutilans (Pruvot-Fol, 1931) es sinonimizada con N. purpureolineata. N. Nembrotha yonowae Goethel and Debelius, 1992 es sinonimizada con N. guttata. Se redescriben las rádulas de Nembrotha milleri Gosliner and Behrens, 1997 and N. mullineri Gosliner and Behrens, 1997

Revealing morphological characteristics of Goniodorididae genera (Mollusca: Nudibranchia)

Detailed knowledge of the anatomy of the species is an essential element in taxonomic studies, since it allows the comparison and differentiation of separate groups of taxa. It becomes especially important when considering type species, as the subsequent identification of the species that compose the taxa is based on its characteristics, considered common in the group. However, despite its relevance, there are still numerous species without detailed descriptions, being especially significant among invertebrates. The family Goniodorididae is a little-known group of nudibranchs that includes eight recognized genera: Okenia, Goniodoris, Ancula, Lophodoris, Spahria, Trapania, Goniodoridella and Murphydoris. Several of their species are not completely described, including type species, and the systematics of the family is still unclear. Here we study in detail the external morphology and internal anatomy of the type species of five of the eight Goniodorididae genera using microcomputed tomography and scanning electron microscopy. We include the species Okenia elegans, Goniodoris nodosa, Ancula gibbosa, Goniodoridella savignyi and Murphydoris singaporensis as well as one species of Trapania, T. graeffei. We describe for the first time the detailed internal anatomy of the type species Goniodoridella savignyi. The diagnostic features of each genus are compared, and a preliminary framework is shown to clarify their systematics and identification

A Spanish dancer? No! A troupe of dancers: a review of the family Hexabranchidae Bergh, 1891 (Gastropoda, Heterobranchia, Nudibranchia): A troupe of Spanish dancer

Color ontogeny and variations associated with discrete morphological differences may generate taxonomical challenges, which requires multiple data types and in-depth historical review. The nudibranch known as the Spanish dancer, Hexabranchus sanguineus, is a classic example with over 200 years of taxonomic confusion. Currently, H. sanguineus is accepted by most authors as a single species from the Indo-Pacific Ocean with Hexabranchus morsomus as a valid species from the Atlantic Ocean. Yet, despite these species being highly studied, their systematic status remains debatable. Over 30 synonyms have been proposed for H. sanguineus and even a distinct genus for H. morsomus. Here we provide, for the first time, a comprehensive review of all proposed names and an integrative taxonomic revision of the genus including morphological and molecular data. Our results reveal that H. sanguineus is a complex of five species: four previously described and an undescribed species, one of the largest nudibranchs in the world: Hexabranchus giganteus sp. nov. The genus Caribranchus is considered a junior synonym of Hexabranchus Ehrenberg, 1828 and the ontogeny of color pattern is discussed

Traditional Taxonomic Groupings Mask Evolutionary History: A Molecular Phylogeny and New Classification of the Chromodorid Nudibranchs

Chromodorid nudibranchs (16 genera, 300+ species) are beautiful, brightly colored sea slugs found primarily in tropical coral reef habitats and subtropical coastal waters. The chromodorids are the most speciose family of opisthobranchs and one of the most diverse heterobranch clades. Chromodorids have the potential to be a model group with which to study diversification, color pattern evolution, are important source organisms in natural products chemistry and represent a stunning and widely compelling example of marine biodiversity. Here, we present the most complete molecular phylogeny of the chromodorid nudibranchs to date, with a broad sample of 244 specimens (142 new), representing 157 (106 new) chromodorid species, four actinocylcid species and four additional dorid species utilizing two mitochondrial markers (16s and COI). We confirmed the monophyly of the Chromodorididae and its sister group relationship with the Actinocyclidae. We were also able to, for the first time, test generic monophyly by including more than one member of all 14 of the non-monotypic chromodorid genera. Every one of these 14 traditional chromodorid genera are either non-monophyletic, or render another genus paraphyletic. Additionally, both the monotypic genera Verconia and Diversidoris are nested within clades. Based on data shown here, there are three individual species and five clades limited to the eastern Pacific and Atlantic Oceans (or just one of these ocean regions), while the majority of chromodorid clades and species are strictly Indo-Pacific in distribution. We present a new classification of the chromodorid nudibranchs. We use molecular data to untangle evolutionary relationships and retain a historical connection to traditional systematics by using generic names attached to type species as clade names

Synthase-selected sorting approach identifies a beta-lactone synthase in a nudibranch symbiotic bacterium

[Background] Nudibranchs comprise a group of > 6000 marine soft-bodied mollusk species known to use secondary metabolites (natural products) for chemical defense. The full diversity of these metabolites and whether symbiotic microbes are responsible for their synthesis remains unexplored. Another issue in searching for undiscovered natural products is that computational analysis of genomes of uncultured microbes can result in detection of novel biosynthetic gene clusters; however, their in vivo functionality is not guaranteed which limits further exploration of their pharmaceutical or industrial potential. To overcome these challenges, we used a fluorescent pantetheine probe, which produces a fluorescent CoA-analog employed in biosynthesis of secondary metabolites, to label and capture bacterial symbionts actively producing these compounds in the mantle of the nudibranch Doriopsilla fulva.[Results] We recovered the genome of Candidatus Doriopsillibacter californiensis from the Ca. Tethybacterales order, an uncultured lineage of sponge symbionts not found in nudibranchs previously. It forms part of the core skin microbiome of D. fulva and is nearly absent in its internal organs. We showed that crude extracts of D. fulva contained secondary metabolites that were consistent with the presence of a beta-lactone encoded in Ca. D. californiensis genome. Beta-lactones represent an underexplored group of secondary metabolites with pharmaceutical potential that have not been reported in nudibranchs previously.[Conclusions] Altogether, this study shows how probe-based, targeted sorting approaches can capture bacterial symbionts producing secondary metabolites in vivo.The work (proposal: 10.46936/10.25585/60000940) conducted by the U.S. Department of Energy Joint Genome Institute (https://ror.org/04xm1d337), a DOE Office of Science User Facility, is supported by the Office of Science of the U.S. Department of Energy operated under Contract No. DE-AC02-05CH11231. RS, MB, JL, and TW are supported by NIH grant R01AI168993. The John Templeton Foundation (grant nos. 51250 and 60973) supported TT and SVD, and the Gordon and Betty Moore Foundation grants (GBMF7617 and GBMF9340) supported SVD. MD is supported by the Generalitat Valenciana program GenT grant number CDEIGENT/2021/008. SPE is supported by a FPU grant from the Spanish Ministry of Universities (Reference: FPU20/05756).Peer reviewe

The Systematics of the Aeolidacea (Nudibranchia: Mollusca) of the Hawaiian Islands, with Descriptions of Two New Species

Nineteen species of aeolid nudibranchs are here recorded from the Hawaiian Islands. The natural history and distribution of each species is described. Morphological accounts of these taxa are provided and their systematic status is discussed. The status of an additional three species, previously recorded from the Hawaiian Islands but not encountered in this study, is reviewed. Based on the study of the Hawaiian aeolidacean nudibranch fauna, the systematics of the Facelinidae are reviewed. An examination of the zoogeographical affinities of the Hawaiian aeolid fauna suggests that many taxa have a typical Indo-West Pacific distribution. However, a significant portion of the fauna is substantially more widely distributed and appears to be circumtropical