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Once considered the most speciose mostly azooxanthellate scleractinian group, the family Caryophylliidae is found to be highly polyphyletic based on molecular data and is undergoing a process of systematic revision. High‐throughput sequencing methods coupled with morphological analyses have facilitated revision of several scleractinian lineages, including the aforementioned family. In previous studies that relied on few mitochondrial and nuclear markers, the caryophylliid genera Stephanocyathus and Vaughanella were phylogenetically recovered in separate clades from the lineage that includes the type genus of the family, Caryophyllia, which is considered the 'true' Caryophylliidae. To help untangle the relationship among taxa of this family, here a new deep‐sea scleractinian family (Stephanocyathidae Vaga, Cairns & Kitahara fam. nov.) is proposed based on phylogenomic reconstructions coupled with molecular features, specifically gene order, of the complete mitochondrial genome. Evolutionary reconstructions were based on both mitochondrial and nuclear ultraconserved elements (UCEs) and exon loci data sets and confirmed the divergent position of the genera Stephanocyathus and Vaughanella. The new family shows a specific gene transposition in the mitochondrial genome, not present in the 'true' caryophylliid lineage, but instead already observed for the species Paraconotrochus antarcticus, recovered as sister taxon of the here proposed new family. Although its phylogenetic position is unknown, the genus Ericiocyathus is also added to the new family, based on macromorphological similarities. This study represents a step forward in our understanding of deep‐sea corals relationships and provide further information (e.g., mitochondrial gene order) that will aid in future efforts of assessing the systematic of caryophylliid lineages. [ABSTRACT FROM AUTHOR]

The integration of morphological and molecular lines of evidence has enabled the family Deltocyathidae to be erected to accommodate Deltocyathus species that were previously ascribed to the family Caryophylliidae. However, although displaying the same morphological characteristics as other species of Deltocyathus, molecular data suggested that D. magnificus was phylogenetically distant from Deltocyathidae, falling within the family Turbinoliidae instead. To elucidate the enigmatic evolutionary history of this species and skeletal microstructural features, the phylogenetic relationships of Deltocyathidae and Turbinoliidae were investigated using nuclear ultraconserved and exon loci and complete mitochondrial genomes. Both nuclear and mitochondrial phylogenomic reconstructions confirmed the position of D. magnificus within turbinolids. Furthermore, a novel mitochondrial gene order was uncovered for Deltocyathidae species. This gene order was not present in Turbinoliidae or in D. magnificus that both have the scleractinian canonical gene order, further indicating the taxonomic utility of mitochondrial gene order. D. magnificus is therefore formally moved to the family Turbinoliidae and accommodated in a new genus (Dennantotrochus Kitahara, Vaga & Stolarski, gen. nov.). Surprisingly, turbinolids and deltocyathids do not differ in microstructural organisation of the skeleton that consists of densely packed, individualised rapid accretion deposits and thickening deposits composed of fibres perpendicular to the skeleton surface. Therefore, although both families are clearly evolutionarily divergent, macromorphological features indicate a case of skeletal convergence while these may still share conservative biomineralisation mechanisms. [ABSTRACT FROM AUTHOR]

Deep-sea lineages are generally thought to arise from shallow-water ancestors, but this hypothesis is based on a relatively small number of taxonomic groups. Anthozoans, which include corals and sea anemones, are significant contributors to the faunal diversity of the deep sea, but the timing and mechanisms of their invasion into this biome remain elusive. Here, we reconstruct a fully resolved, time-calibrated phylogeny of 83 species in the order Antipatharia (black coral) to investigate their bathymetric evolutionary history. Our reconstruction indicates that extant black coral lineages first diversified in continental slope depths (∼250–3000 m) during the early Silurian (∼437 millions of years ago (Ma)) and subsequently radiated into, and diversified within, both continental shelf (less than 250 m) and abyssal (greater than 3000 m) habitats. Ancestral state reconstruction analysis suggests that the appearance of morphological features that enhanced the ability of black corals to acquire nutrients coincided with their invasion of novel depths. Our findings have important conservation implications for anthozoan lineages, as the loss of 'source' slope lineages could threaten millions of years of evolutionary history and confound future invasion events, thereby warranting protection. [ABSTRACT FROM AUTHOR]

Target‐capture approaches have facilitated a rapid growth in the field of phylogenomics but few probe sets exist for molluscs, an exceptionally rich phylum with unparalleled ecological and morphological diversity. We designed and tested the first universal probe set using Phyluce to capture ultraconserved elements (UCEs) and exon loci from the Subclass Caenogastropoda ‐ one of six major lineages of gastropods. The probe set consists of 29,441 probes designed to target 1142 UCE loci and 1933 exon loci (3075 total). In silico analyses of our probe set yielded an average of 2110 loci from genomes and 1389 loci from transcriptomes of diverse caenogastropods, from which an average of 1669 and 849 loci were retained respectively after screening to remove those that matched multiple contigs. Phylogenetic analyses of the loci extracted from transcriptomes produced well‐supported trees very similar to those published based on transcriptomic analyses. Phylogenetic relationships estimated from loci extracted from genomes recover similar phylogenetic relationships, and indicate that the loci targeted with this probe set are informative for resolving deep phylogenetic relationships. An in vitro analysis of the probe set with the Epitoniidae, a diverse caenogastropod family of uncertain affinity and with poorly resolved evolutionary relationships, recovered a total of 2850 loci. Although preliminary, the analysis of loci captured by our probe set for a small number of epitoniid taxa produced a well‐resolved tree indicating that this probe set is also able to resolve relationships at shallower hierarchical scales. Together, the in silico and in vitro analyses indicate that target‐capture enrichment with this probe set is a useful tool for reconstructing phylogenetic relationships across taxonomic levels and evolutionary time scales. [ABSTRACT FROM AUTHOR]

Black corals (Anthozoa: Antipatharia) are an anthozoan lineage in the class Hexacorallia that occur across a wide range of habitats from the tropics to the poles and from surface waters to depths deeper than 8000 m. A new species of black coral, Aphanipathes puertoricoensis sp. nov., collected with a remotely operated vehicle 357 m deep off Puerto Rico is recognized in the family Aphanipathidae. The new species is characterized by very long and loosely coiled primary branches and up to 0.5 mm tall spines with as many as 40 or more small conical tubercles. A phylogeny composed of 13 taxa that are closely related to the new species was reconstructed from 793 nuclear loci to show their systematic relationships. Our study integrated morphological and genomic data to show that this new species is distinct from other species in the genus Aphanipathes. Furthermore, our results add to the growing knowledge of black coral diversity, while further demonstrating the need for exploration in deep waters of the Caribbean Sea. [ABSTRACT FROM AUTHOR]

• Genomic capture methods can resolve clades that lack decades of molecular marker development. • An enhanced bait setfor Hexacorallia recovers >2400 UCE/exon loci in stony corals. • Phylogenomics resolves coral relationships at deep and shallow time scales. • Well-supported clades in Acropora are not supported by macromorphological features. Targeted enrichment of genomic DNA can profoundly increase the phylogenetic resolution of clades and inform taxonomy. Here, we redesign a custom bait set previously developed for the cnidarian class Anthozoa to more efficiently target and capture ultraconserved elements (UCEs) and exonic loci within the subclass Hexacorallia. We test this enhanced bait set (targeting 2476 loci) on 99 specimens of scleractinian corals spanning both the "complex" (Acroporidae, Agariciidae) and "robust" (Fungiidae) clades. Focused sampling in the staghorn corals (genus Acropora) highlights the ability of sequence capture to inform the taxonomy of a clade previously deficient in molecular resolution. A mean of 1850 (±298) loci were captured per taxon (955 UCEs, 894 exons), and a 75% complete concatenated alignment of 96 samples included 1792 loci (991 UCE, 801 exons) and ~1.87 million base pairs. Maximum likelihood and Bayesian analyses recovered robust molecular relationships and revealed that species-level relationships within the Acropora are incongruent with traditional morphological groupings. Both UCE and exon datasets delineated six well-supported clades within Acropora. The enhanced bait set will facilitate investigations of the evolutionary history of many important groups of reef corals, particularly where previous molecular marker development has been unsuccessful. [ABSTRACT FROM AUTHOR]

[Display omitted] • For the first time, deep nodes are resolved within the Keratoisididae, a prolific deep-sea family of octocorals. • Nuclear phylogenies built with hundreds of genes conflict with previously published single and multi-gene mitochondrial phylogenies. • Some currently recognised keratoisidid groups appear polyphyletic using nuclear phylogenies built with hundreds of markers. • Sclerite microstructure and ornamentation could be future informative taxonomic features for bamboo corals. Keratoisididae is a globally distributed, and exclusively deep-sea, family of octocorals that contains species and genera that are polyphyletic. An alphanumeric system, based on a three-gene-region phylogeny, is widely used to describe the biodiversity within this family. That phylogeny identified 12 major groups although it did not have enough signal to explore the relationships among groups. Using increased phylogenomic resolution generated from Ultraconserved Elements and exons (i.e. conserved elements), we aim to resolve deeper nodes within the family and investigate the relationships among those predefined groups. In total, 109 libraries of conserved elements were generated from individuals representing both the genetic and morphological diversity of our keratoisidids. In addition, the conserved element data of 12 individuals from previous studies were included. Our taxon sampling included 11 of the 12 keratoisidid groups. We present two phylogenies, constructed from a 75% (231 loci) and 50% (1729 loci) taxon occupancy matrix respectively, using both Maximum Likelihood and Multiple Species Coalescence methods. These trees were congruent at deep nodes. As expected, S1 keratoisidids were recovered as a well-supported sister clade to the rest of the bamboo corals. S1 corals do not share the same mitochondrial gene arrangement found in other members of Keratoisididae. All other bamboo corals were recovered within two major clades. Clade I comprises individuals assigned to alphanumeric groups B1, C1, D1&D2, F1, H1, I4, and J3 while Clade II contains representatives from A1, I1, and M1. By combining genomics with already published morphological data, we provide evidence that group H1 is not monophyletic, and that the division between other groups – D1 and D2, and A1 and M1 – needs to be reconsidered. Overall, there is a lack of robust morphological markers within Keratoisididae, but subtle characters such as sclerite microstructure and ornamentation seem to be shared within groups and warrant further investigation as taxonomically diagnostic characters. [ABSTRACT FROM AUTHOR]