Morphology and molecular phylogeny of three black corals(Antipatharia,Schizopathidae)from seamounts in the Western Pacific Ocean,with description of a new species

Three deep-sea black corals belonging to the family Schizopathidae,are reported from two seamounts on the Caroline Ridge in the tropical Western Pacific:Umbellapathes parva sp.nov.with depth of 1488-1766 m,Telopathes cf.magna MacIsaac&Best,2013 with depth of 937-1016 m,and Stauropathes cf.punctata(Roule,1905)with depth of 942-1353 m.The latter two species are the first records in the Western Pacific Ocean.U.parva sp.nov.is characterized by monopodial corallum,relatively long unpinnulated stalk with complex pinnulated branche s developing from the lowermost primary pinnules and small spine s.It differs from two known congeners by much smaller spine s and the present of secondary pinnules.T.cf.magna MacIsaac&Best,2013 has sparsely branched corallum,relatively long and simple pinnules arranged in subopposite or alternate pairs.S.cf.punctata(Roule,1905)is characterized by the corallum with almost planar pinnulated branches,and pinnules arranged in subopposite pairs.Our results indicate that the corallum size and shape are variable in conspecific specimens particularly those at different growth stages.By contrast,the size of the polypar spines as well as the abpolypar spines have little variation and can be served as a main differing feature for schizopathid species.The phylogenetic analyses using nuclear internal transcribed spacer region(spanning partial 18 S rDNA,ITS 1,5.8 S,ITS2,and partial 28 S rDNA)and two mitochondrial fragments cox3-IGR-coxl(COI)and trnW-IGR-nad2(NAD2)showed Telopathes,Stau ropathes,and Bathypathes had close relationships,and Umbellapathes formed a sister clade with Alternatipathes.

Paragorgia papillata sp.nov.,a new bubblegum coral(Octocorallia:Paragorgiidae)from a seamount in the tropical Western Pacific

A new species of bubblegum coral,Paragorgia papillata sp.nov.,discovered from a seamount located on the Caroline Ridge at the water depth of 858 m,is studied using morphological and molecular approaches.The new gorgonian is white-colored,uniplanar with prominent autozooids,and measures about670-mm high and 690-mm wide.The genetic distance and phylogenetic analysis showed that P.papillata sp.nov.was closely related to P.coralloides Bayer,1993,but the former differs morphologically from the latter by its prominent calyces(diameter 2.0-4.0 mm and height 1.5-3.0 mm vs.both diameter and height about 1 mm),white cortex(vs.pink),regular 8-radiates in surface cortex(vs.mostly 8-radiate derived globular radiates)and highly ornate medullar spindles(length 185-400μm vs.no more than 150μm).P.papillata sp.nov.is the third known white-colored species of the genus,and the fifth species found in the tropical Western Pacific.

Establishment of Alloptilella splendida gen.et sp.nov.and resurrection of Scytalium veneris(Thomson&Henderson,1906),two sea pens(Cnidaria:Pennatulacea)from seamounts in the tropical Western Pacific

Sea pens are a highly specialized and morphologically distinct group of octocorallians,but many taxa were poorly described and their phylogenetic relationships are still poorly known.We describe two species of sea pens collected from the tropical Western Pacific:Alloptilella splendida gen.et sp.nov.and Scytalium veneris(Thomson&Henderson,1906).Alloptilella splendida gen.et sp.nov.accords with the definition of the recently resurrected genus Ptilella Gray,1870 in most characters,but differs from the latter in the arrangement of autozooids and the location of mesozooids.The new species mostly resembles Pennatula naresi K(o|")lliker(1880),but differs by the location of me sozooids and the reddish color of sclerite s surrounding siphonozooids.The generic separation is also well supported by their genetic distances and the molecular phylogenetic trees constructed by the concatenated mtMutS-COI-28 S,where Alloptilella clustered with Scytalium Herklots,1858 and formed a clade with the cluster of Ptilella and Distichoptilum.Scytalium veneris,usually considered as a junior synonym of Scytalium sarsii Herklots,1858,is resurrected by recognizing their distinctive differences.This is the first record of Scytalium veneris outside its type locality,and the phylogenetic analysis indicates that Scytalium is a monophyletic group.Both the families Pennatulidae and Virgulariidae are polyphyletic,and more morphological and molecular data are needed to clarify the phylogenetic positions of pennatulacean families and genera.

Morphology and phylogeny of Chrysogorgia pinniformis sp.nov.and C.varians sp.nov.,two golden corals from the Caroline seamounts in the tropical Western Pacific Ocean

Two new species of Chrysogorgia Duchassaing&Michelotti,1864 collected from the Caroline seamounts in the tropical Western Pacific Ocean are described.Chrysogorgia pinniformis sp.nov.belongs to Versluys’group C(Squamosae typicae)with only scales in polyp body wall and tentacles.C.pinniformis sp.nov.is characterized by large branches pinnately branched and forming multiple fans with its small branches regularly and quasi-dichotomous branched,and scales and rods present in the polyp mouth area.It is most similar to C.pinnata Cairns,2007 by the pinnate trait,but differs from the latter by its group C pattern(vs.group A,Spiculosae)and having sclerites present in the polyp mouth area(vs.absent).Chrysogorgia varians sp.nov.belongs to the Chrysogorgia group A(Spiculosae)with rods distributed in the polyp body wall and tentacles.It is characterized by warty rods and elongated scales in the tentacles,many warts and ridges on the scales,conspicuously toothed margins at the rounded ends in the pinnules,and small rods with ridge-like warts in the polyp mouth area.This species was frequent and abundant in the Caroline seamounts during our cruises and its morphological variability in growth period was obvious.The phylogenetic analyses based on mtMutS and 28 S rDNA regions supported the assignment of the new species to the genus Chrysogorgia.However,the mtMutS marker showed very limited usefulness for species delimitation and inner relationship inference of Chrysogorgia.In contrast,the 28 S rDNA showed much higher level of genetic variation,and it may be a potential barcode for this genus.In the 28 S rDNA trees,the two new species clustered together.Additionally,compilation of our data showed that 42 of 78(ca.54%)Chrysogorgia species were found in the Indo-West Pacific convergent region,indicating that this area may be a hotspot of deep-water Chrysogorgia species.

Blooms of Prorocentrum donghaiense reduced the species diversity of dinoflagellate community

Most of reported harmful algal blooms(HABs)of microalgae(75%)have been caused by dinoflagellates.Studies on the negative effects of HABs have generally focused on animals,valuable organisms in particular,and environmental factors such as dissolved oxygen and nutrients,but relatively fewer on community level,particularly that using metagenomic approach.In this study,we reported an investigation on the effects of a HAB caused by the dinoflagellate Prorocentrum donghaiense on the species diversity and community structure of the dinoflagellate sub-community via a pyrosequencing approach for the samples taken before,during,and after the bloom season of P.donghaiense in the East China Sea.We sequenced partial 28S rRNA gene of dinoflagellates for the field samples and evaluated the species richness and diversity indices of the dinoflagellate community,as a sub-community of the total phytoplankton.We obtained 800185 valid sequences(categorized into 560 operational taxonomic units,OTUs)of dinoflagellates from 50 samples and found that the biodiversity of dinoflagellate community was significantly reduced during the blooming period in comparison to that in pre-and after-blooming periods,as reflected in the four diversity indices:the species richness expressed as the number of OTUs,Chao1 index,Shannon index(evenness),and Gini-Simpson index.These four indices were all found to be negatively correlated to the cell density of the bloom species P.donghaiense.Correlation analyses also revealed that the P.donghaiense cell abundance was correlated negatively with NO3--N,and NO2--N,but positively with total nitrogen(TN)and total phosphorus(TP).Principal coordinates analysis(PCoA)showed that the community structure of dinoflagellates was markedly different among the different sampling periods,while the redundancy analysis(RDA)revealed P.donghaiense abundance,salinity,NO3--N,and SiO32-were the most four significant factors shaping the dinoflagellate community structure.Our results together demonstrated that HABs caused by the dinoflagellate P.donghaiense could strongly impact the aquatic ecosystem on the sub-community level which the blooming species belongs to.

Detection of two pathogenic marine ciliates Ancistrum haliotis and A. crassum(Ciliophora: Scuticociliatia) by fluorescence in situ hybridization

The scuticociliatid ciliates Ancistrum haliotis and A.crassum are parasites that may cause high mortality in the cultured abalone Haliotis spp.and the bivalve Ruditapes philippinarum.Traditional identification with silver staining methods is hampered by their morphological similarities to closely related species and the complicated procedures of morphological analysis.We designed two SSU rRNA-targeted oligonucleotide probes labeled with a fluorochrome,and optimized the fluorescence in situ hybridization(FISH)protocols for identification of A.halioti and A.crassum,respectively.The assays resulted in a clear identification by strong fluorescence signals from the oligonucleotide probes.The method can be used for quick and accurate quantitative analysis of A.haliotis and A.crassum infections on host molluscs.