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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]

Extant biodiversity can easily be underestimated owing to the presence of cryptic taxa, even among commonly observed species. Scleractinian corals are challenging to identify because of their ecophenotypic variation and morphological plasticity. In addition, molecular analyses have revealed the occurrence of cryptic speciation. Here, we describe a new cryptic lobophylliid genus and species Paraechinophyllia variabilis gen. nov., sp. nov., which is morphologically similar to Echinophyllia aspera and E. orpheensis. The new taxon occurs in Mayotte Island, Madagascar, the Gulf of Aden and the Red Sea. Six molecular markers (COI, 12S, ATP6‐NAD4, NAD3‐NAD5, histone H3 and ITS) and 46 morphological characters at three different levels (macromorphology, micromorphology and microstructure) were examined. The resulting molecular phylogenetic reconstruction showed that Paraechinophyllia gen. nov. represents a distinct group within the Lobophylliidae that diverged from the lineage leading to Echinophyllia and Oxypora in the Early Miocene, approximately 21.5 Ma. The morphological phylogenetic reconstruction clustered Paraechinophyllia gen. nov., Echinophyllia and Oxypora together in a single clade. A sole morphological character, calice relief, discriminated Paraechinophyllia gen. nov. from the latter two genera, suggesting that limited morphological variation has occurred over a long period. These results highlight the importance of cryptic taxa in reef corals, with implications for population genetics, ecological studies and conservation. [ABSTRACT FROM AUTHOR]

Background: Classical morphological taxonomy places the approximately 1400 recognized species of Scleractinia (hard corals) into 27 families, but many aspects of coral evolution remain unclear despite the application of molecular phylogenetic methods. In part, this may be a consequence of such studies focusing on the reef-building (shallow water and zooxanthellate) Scleractinia, and largely ignoring the large number of deep-sea species. To better understand broad patterns of coral evolution, we generated molecular data for a broad and representative range of deep sea scleractinians collected off New Caledonia and Australia during the last decade, and conducted the most comprehensive molecular phylogenetic analysis to date of the order Scleractinia. Methodology: Partial (595 bp) sequences of the mitochondrial cytochrome oxidase subunit 1 (CO1) gene were determined for 65 deep-sea (azooxanthellate) scleractinians and 11 shallow-water species. These new data were aligned with 158 published sequences, generating a 234 taxon dataset representing 25 of the 27 currently recognized scleractinian families. Principal Findings/Conclusions: There was a striking discrepancy between the taxonomic validity of coral families consisting predominantly of deep-sea or shallow-water species. Most families composed predominantly of deep-sea azooxanthellate species were monophyletic in both maximum likelihood and Bayesian analyses but, by contrast (and consistent with previous studies), most families composed predominantly of shallow-water zooxanthellate taxa were polyphyletic, although Acroporidae, Poritidae, Pocilloporidae, and Fungiidae were exceptions to this general pattern. One factor contributing to this inconsistency may be the greater environmental stability of deep-sea environments, effectively removing taxonomic ''noise'' contributed by phenotypic plasticity. Our phylogenetic analyses imply that the most basal extant scleractinians are azooxanthellate solitary corals from deep-water, their divergence predating that of the robust and complex corals. Deep-sea corals are likely to be critical to understanding anthozoan evolution and the origins of the Scleractinia. [ABSTRACT FROM AUTHOR]

The first fossil stylasterid from Antarctic is reported from La Meseta Formation (Telml: Early Eocene) of Seymour Island (Antarctic Peninsula): Conopora mariae sp. nov. This also is the earliest reliable fossil record of the genus Conopora. Conopora mariae differs from congeners by having much larger cyclosystems (diameter 2.5-4.5 mm). Cyclosystems of that size are exceptional among the Stylasteridae. [ABSTRACT FROM AUTHOR]