Mitochondrial genome rearrangements in the Scleractinia/Corallimorpharia complex: implications for coral phylogeny

Corallimorpharia is a small Order of skeleton-less animals that is closely related to the reef-building corals (Scleractinia) and of fundamental interest in the context of understanding the potential impacts of climate change in the future on coral reefs. The relationship between the nominal Orders Corallimorpharia and Scleractinia is controversial-the former is either the closest outgroup to the Scleractinia or alternatively is derived from corals via skeleton loss. This latter scenario, the "naked coral" hypothesis, is strongly supported by analyses based on mitochondrial (mt) protein sequences, whereas the former is equally strongly supported by analyses of mt nucleotide sequences. The "naked coral" hypothesis seeks to link skeleton loss in the putative ancestor of corallimorpharians with a period of elevated oceanic CO2 during the Cretaceous, leading to the idea that these skeleton-less animals may be harbingers for the fate of coral reefs under global climate change. In an attempt to better understand their evolutionary relationships, we examined mt genome organization in a representative range (12 species, representing 3 of the 4 extant families) of corallimorpharians and compared these patterns with other Hexacorallia. The most surprising finding was that mt genome organization in Corallimorphus profundus, a deep-water species that is the most scleractinian-like of all corallimorpharians on the basis of morphology, was much more similar to the common scleractinian pattern than to those of other corallimorpharians. This finding is consistent with the idea that C. profundus represents a key position in the coral corallimorpharian transition

Mitochondrial genome rearrangements in the Scleractinia / Corallimorpharia complex: implications for coral phylogeny

Corallimorpharia is a small Order of skeleton-less animals that is closely related to the reef-building corals (Scleractinia) and of fundamental interest in the context of understanding the potential impacts of climate change in the future on coral reefs. The relationship between the nominal Orders Corallimorpharia and Scleractinia is controversial – the former is either the closest outgroup to the Scleractinia or, alternatively is derived from corals via skeleton loss. This latter scenario, the “naked coral” hypothesis, is strongly supported by analyses based on mitochondrial protein sequences, whereas the former is equally strongly supported by analyses of mitochondrial (mt) nucleotide sequences. The “naked coral” hypothesis seeks to link skeleton loss in the putative ancestor of corallimorpharians with a period of elevated oceanic CO2 during the Cretaceous, leading to the idea that these skeleton-less animals may be harbingers for the fate of coral reefs under global climate change. In an attempt to better understand their evolutionary relationships, we examined mitochondrial genome organization in a representative range (12 species, representing 3 of the 4 extant families) of corallimorpharians and compared these patterns to other Hexacorallia. The most surprising finding was that mt genome organization in Corallimorphus profundus, a deep-water species that is the most scleractinian-like of all corallimorpharians on the basis of morphology, was much more similar to the common scleractinian pattern than to those of other corallimorpharians. This finding is consistent with the idea that C. profundus represents a key position in the coral <-> corallimorpharian transition.São Paulo Research Foundation (FAPESP)São Paulo University Marine Biology Centre (CEBIMar)National Science Council (NSC) and Academia Sinica (Thematic Grants 2005–2010) to C.A.C.Australian Research Council to D.J.M. Cora

Control of Domain Wall Position by Electrical Current in Structured Co/Ni Wire with Perpendicular Magnetic Anisotropy

We report the direct observation of the current-driven domain wall (DW) motion by magnetic force microscopy in a structured Co/Ni wire with perpendicular magnetic anisotropy. The wire has notches to define the DW position. It is demonstrated that single current pulses can precisely control the DW position from notch to notch with high DW velocity of 40 m/s.Comment: 12 pages, 3 figure

Mitochondrial and nuclear genes suggest that stony corals are monophyletic but most families of stony corals are not (Order Scleractinia, Class Anthozoa, Phylum Cnidaria)

Modern hard corals (Class Hexacorallia; Order Scleractinia) are widely studied because of their fundamental role in reef building and their superb fossil record extending back to the Triassic. Nevertheless, interpretations of their evolutionary relationships have been in flux for over a decade. Recent analyses undermine the legitimacy of traditional suborders, families and genera, and suggest that a non-skeletal sister clade (Order Corallimorpharia) might be imbedded within the stony corals. However, these studies either sampled a relatively limited array of taxa or assembled trees from heterogeneous data sets. Here we provide a more comprehensive analysis of Scleractinia (127 species, 75 genera, 17 families) and various outgroups, based on two mitochondrial genes (cytochrome oxidase I, cytochrome b), with analyses of nuclear genes (ßtubulin, ribosomal DNA) of a subset of taxa to test unexpected relationships. Eleven of 16 families were found to be polyphyletic. Strikingly, over one third of all families as conventionally defined contain representatives from the highly divergent "robust" and "complex" clades. However, the recent suggestion that corallimorpharians are true corals that have lost their skeletons was not upheld. Relationships were supported not only by mitochondrial and nuclear genes, but also often by morphological characters which had been ignored or never noted previously. The concordance of molecular characters and more carefully examined morphological characters suggests a future of greater taxonomic stability, as well as the potential to trace the evolutionary history of this ecologically important group using fossils

Analysis of complete miochondrial DNA sequences of three members of the Montastraea annularis coral species complex (Cnidaria, Anthozoa, Scleractinia)

Complete mitochondrial nucleotide sequences of two individuals each of Montastraea annularis,Montastraea faveolata, and Montastraea franksi were determined. Gene composition and order di•ered substantially from the sea anemone Metridium senile, but were identical to that of the phylogenetically distant coral genus Acropora. However, characteristics of the noncoding regions di•ered between the two scleractinian genera. Among members of the M. annularis complex, only 25 of 16,134 base pair positions were variable. Sixteen of these occurred in one colony ofM. franksi, which (together with additional data) indicates the existence of multiple divergent mitochondrial lineages in this species. Overall, rates of evolution for these mitochondrial genomes were extremely slow (0.03–0.04% per million years based on the fossil record of the M. annularis complex). At higher taxonomic levels, patterns of genetic divergence and synonymous/nonsynonymous substitutions suggest non-neutral and unequal rates of evolution between the two lineages to which Montastraea and Acropora belong

High species diversity of the soft coral family Xeniidae (Octocorallia, Alcyonacea) in the temperate region of Japan revealed by morphological and molecular analyses

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Xenia konohana sp. nov. (Cnidaria, Octocorallia, Alcyonacea), a new soft coral species in the family Xeniidae from Miyazaki, Japan

A new soft coral species, Xenia konohana sp. nov. (Alcyonacea, Xeniidae), is described from Miyazaki in the warm-temperate region of Japan. This new species has conspicuous and unique spindle sclerites in addition to the simple ellipsoid platelet-shaped sclerites typically found in the genus Xenia. These unique spindles are a specific key morphological characteristic for this new species and for differentiating this species among congeneric species

Xenia konohana sp. nov. (Cnidaria, Octocorallia, Alcyonacea), a new soft coral species in the family Xeniidae from Miyazaki, Japan

A new soft coral species, Xenia konohana sp. nov. (Alcyonacea, Xeniidae), is described from Miyazaki in the warm-temperate region of Japan. This new species has conspicuous and unique spindle sclerites in addition to the simple ellipsoid platelet-shaped sclerites typically found in the genus Xenia. These unique spindles are a specific key morphological characteristic for this new species and for differentiating this species among congeneric species