The ancient evolutionary origins of Scleractinia revealed by azooxanthellate corals

Background: Scleractinian corals are currently a focus of major interest because of their ecological importance and the uncertain fate of coral reefs in the face of increasing anthropogenic pressure. Despite this, remarkably little is known about the evolutionary origins of corals. The Scleractinia suddenly appear in the fossil record about 240 Ma, but the range of morphological variation seen in these Middle Triassic fossils is comparable to that of modern scleractinians, implying much earlier origins that have so far remained elusive. A significant weakness in reconstruction(s) of early coral evolution is that deep-sea corals have been poorly represented in molecular phylogenetic analyses

Clone wars:asexual reproduction dominates in the invasive range of Tubastraea spp. (Anthozoa: Scleractinia) in the South-Atlantic Ocean

Although the invasive azooxanthellate corals Tubastraea coccinea and T. tagusensis are spreading quickly and outcompeting native species in the Atlantic Ocean, there is little information regarding the genetic structure and path of introduction for these species. Here we present the first data on genetic diversity and clonal structure from these two species using a new set of microsatellite markers. High proportions of clones were observed, indicating that asexual reproduction has a major role in the local population dynamics and, therefore, represents one of the main reasons for the invasion success. Although no significant population structure was found, results suggest the occurrence of multiple invasions for T. coccinea and also that both species are being transported along the coast by vectors such as oil platforms and monobouys, spreading these invasive species. In addition to the description of novel microsatellite markers, this study sheds new light into the invasive process of Tubastraea.Coordenacao de Aperfeicoamento de Pessoal de Nivel SuperiorFundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de JaneiroConselho Nacional de Desenvolvimento Cientifico e TecnologicoFundacao de Amparo a Pesquisa do Estado de Sao PauloNSF-OA (National Science Foundation)Univ Fed Rio de Janeiro, Dept Zool, Rio De Janeiro, BrazilUniv Hawaii Manoa, Hawaii Inst Marine Biol, Sch Ocean & Earth Sci & Technol, Kaneohe, HI USACoral Sol Res Technol Dev & Innovat Network, Rio De Janeiro, BrazilUniv Fed Rio de Janeiro, Inst Microbiol Paulo Goes, Rio De Janeiro, BrazilUniv Estado Rio de Janeiro, Dept Ecol, Rio De Janeiro, BrazilUniv Fed Sao Paulo, Dept Ciencias Mar, Santos, BrazilUniv Sao Paulo, Ctr Biol Marinha, Sao Sebastiao, BrazilUniv Fed Sao Paulo, Dept Ciencias Mar, Santos, BrazilCAPES: 1137/2010FAPERJ: E26/010.003031/2014FAPERJ: E26/201.286/2014CNPq: 305330/2010-1FAPESP: 2014/01332-0Web of Scienc

A hybrid-capture approach to reconstruct the phylogeny of Scleractinia (Cnidaria: Hexacorallia)

A well-supported evolutionary tree representing most major lineages of scleractinian corals is in sight with the development and application of phylogenomic approaches. Specifically, hybrid-capture techniques are shedding light on the evolution and systematics of corals. Here, we reconstructed a broad phylogeny of Scleractinia to test previous phylogenetic hypotheses inferred from a few molecular markers, in particular, the relationships among major scleractinian families and genera, and to identify clades that require further research. We analysed 449 nuclear loci from 422 corals, comprising 266 species spanning 26 families, combining data across whole genomes, transcriptomes, hybrid capture and low-coverage sequencing to reconstruct the largest phylogenomic tree of scleractinians to date. Due to the large number of loci and data completeness (less than 38% missing data), node supports were high across shallow and deep nodes with incongruences observed in only a few shallow nodes. The “Robust” and “Complex” clades were recovered unequivocally, and our analyses confirmed that Micrabaciidae Vaughan, 1905 is sister to the “Robust” clade, transforming our understanding of the “Basal” clade. Several families remain polyphyletic in our phylogeny, including Deltocyathiidae Kitahara, Cairns, Stolarski & Miller, 2012, Caryophylliidae Dana, 1846, and Coscinaraeidae Benzoni, Arrigoni, Stefani & Stolarski, 2012, and we hereby formally proposed the family name Pachyseridae Benzoni & Hoeksema to accommodate Pachyseris Milne Edwards & Haime, 1849, which is phylogenetically distinct from Agariciidae Gray, 1847. Results also revealed species misidentifications and inconsistencies within morphologically complex clades, such as Acropora Oken, 1815 and Platygyra Ehrenberg, 1834, underscoring the need for reference skeletal material and topotypes, as well as the importance of detailed taxonomic work. The approach and findings here provide much promise for further stabilising the topology of the scleractinian tree of life and advancing our understanding of coral evolution

A modern scleractinian coral with a two-component calcite–aragonite skeleton

Until now, all of the ca. 1,800 known modern scleractinian coral species were thought to produce skeletons exclusively of aragonite. Asymbiotic Paraconotrochus antarcticus living in the Southern Ocean is the first example of an extant scleractinian that forms a two-component carbonate skeleton, with an inner structure made of high-Mg calcite and an outer structure composed of aragonite. This discovery adds support to the notion that the coral skeletal formation process is strongly biologically controlled. Mitophylogenomic analysis shows that P. antarcticus represents an ancient scleractinian clade, suggesting that skeletal mineralogy/polymorph of a taxon, once established, is a trait conserved throughout the evolution of that clade.One of the most conserved traits in the evolution of biomineralizing organisms is the taxon-specific selection of skeletal minerals. All modern scleractinian corals are thought to produce skeletons exclusively of the calcium-carbonate polymorph aragonite. Despite strong fluctuations in ocean chemistry (notably the Mg/Ca ratio), this feature is believed to be conserved throughout the coral fossil record, spanning more than 240 million years. Only one example, the Cretaceous scleractinian coral Coelosmilia (ca. 70 to 65 Ma), is thought to have produced a calcitic skeleton. Here, we report that the modern asymbiotic scleractinian coral Paraconotrochus antarcticus living in the Southern Ocean forms a two-component carbonate skeleton, with an inner structure made of high-Mg calcite and an outer structure composed of aragonite. P. antarcticus and Cretaceous Coelosmilia skeletons share a unique microstructure indicating a close phylogenetic relationship, consistent with the early divergence of P. antarcticus within the Vacatina (i.e., Robusta) clade, estimated to have occurred in the Mesozoic (ca. 116 Mya). Scleractinian corals thus join the group of marine organisms capable of forming bimineralic structures, which requires a highly controlled biomineralization mechanism; this capability dates back at least 100 My. Due to its relatively prolonged isolation, the Southern Ocean stands out as a repository for extant marine organisms with ancient traits.Mitogenome sequences data have been deposited in GenBank (MT409109). All other study data are included in the article text and supporting information

A Comprehensive Phylogenetic Analysis of the Scleractinia (Cnidaria, Anthozoa) Based on Mitochondrial CO1 Sequence Data

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.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.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

New records of the genus Crispatotrochus (Scleractinia; Caryophylliidae) from New Caledonia, with description of a new species

During the expeditions Bathus 4 and Norfolk 2 off New Caledonia, three species pertaining to the genus Crispatotrochus were collected: C. rubescens, C. rugosus, and C. septumdentatus sp. nov. This study presents the new records describing and illustrating all species. Also, citation synonyms, type locality, type material, and distribution are provided. A brief revision of the 13 valid Recent species belonging to this genus (plus C. sp. cf. C. cornu and C. sp. A) and an identification key are proposed

A ''Neural'' Enzyme in Nonbilaterian Animals and Algae: Preneural Origins for Peptidylglycine a-Amidating Monooxygenase

Secreted peptides, produced by enzymatic processing of larger precursor molecules, are found throughout the animal kingdom and play important regulatory roles as neurotransmitters and hormones. Many require a carboxy-terminal modification, involving the conversion of a glycine residue into an α-amide, for their biological activity. Two sequential enzymatic activities catalyze this conversion: a monooxygenase (peptidylglycine α-hydroxylating monooxygenase or PHM) and an amidating lyase (peptidyl-α-hydroxyglycine α-amidating lyase or PAL). In vertebrates, these activities reside in a single polypeptide known as peptidylglycine α-amidating monooxygenase (PAM), which has been extensively studied in the context of neuropeptide modification. Bifunctional PAMs have been reported from some invertebrates, but the phylogenetic distribution of PAMs and their evolutionary relationship to PALs and PHMs is unclear. Here, we report sequence and expression data for two PAMs from the coral Acropora millepora (Anthozoa, Cnidaria), as well as providing a comprehensive survey of the available sequence data from other organisms. These analyses indicate that bifunctional PAMs predate the origins of the nervous and endocrine systems, consistent with the idea that within the Metazoa their ancestral function may have been to amidate epitheliopeptides. More surprisingly, the phylogenomic survey also revealed the presence of PAMs in green algae (but not in higher plants or fungi), implying that the bifunctional enzyme either predates the plant/animal divergence and has subsequently been lost in a number of lineages or perhaps that convergent evolution or lateral gene transfer has occurred. This finding is consistent with recent discoveries that other molecules once thought of as neural predate nervous systems