The first report of Silurian internal-wave sediments from South China
Internalwavesarisebyperturbationsthatdisturbthehydrostaticequilibriumbetweengravityandbuoyancyatthepycnocline.Incomparisontotempestitesandturbidites,internalwavesproduceepisodichigh-turbulenceeventsandremobilizethesedimentatthedepthwherethepycnoclineintersectstheseafloor.Internalwaves,internaltidesandtheirassociatedcurrentshavelongbeenobservedandmeasuredonmodernshelvesandcontinentalslopes,yetverylittleisknownfromtherockrecordforalongtime.Overthepastdecade,moreandmoreauthorsnoticedtheinfluenceofinternalwavesonthedevelopmentofheterotrophmetazoanreefsthroughthePhanerozoic. Recently,Dr.LIQijianfromNanjingInstituteofGeologyandPalaeontology,ChineseAcademyofSciencesconductedaresearchonthebryozoanreefsinthelowerHanchiatienFormation,whichcropoutinthelowerpartofthisformationatthesoutherntipofChongqing,SouthwestChina.Thesereefsoccurasmassiveargillaceouslimestones,varyinginsizefrom1.6to2.8minthicknessand6to16mindiameter.Thereefsaresurroundedbygray-greenshalesandsiltyshales(Fig.1).Distinctverticalecozonationispresent,andfourgrowthstageshavebeenrecognized,representedbyfourfaciestypesfrombottomtotop:(1)auloporidcoral-echinoderm-bryozoanpackstone/floatstone,(2)fenestratebryozoan-echinodermbafflestone,(3)Fistulipora-Asperoporaframestone,and(4)Fistuliporaframestone(Fig.2). Ofnote,notracesofalgaeorcyanobacteria(noteventhinmicrobialcrusts)havebeenobservedintheHanchiatienreefs,arguingthatthebryozoanreefsdevelopedbelowthephoticzonebutinnutrient-rich,agitatedwater.Suchconditionsarecommonlyobservedinareaswhereapycnoclinearrivesatashelf,slope,orramp.Inthestudiedsection,internalwaves,probablyinitiatedbytides,propagatelandward,shoal,andeventuallybreakatadepthwherethepycnoclineintersectstheseafloor.Intropicalmid-toouter-rampsettings,thesebryozoanreefsshowcaseanunusualreefcommunityinheterozoancarbonates,whichwereprobablyinfluencedbyinternalwaves. ThisstudywasfinanciallysupportedbytheNationalNaturalScienceFoundationofChina,andtheChineseAcademyofScience.ThisstudyisacontributiontotheIGCP-653‘TheonsetoftheGreatOrdovicianBiodiversityEvent’. Reference:QijianLi,AndrejErnst,AxelMunnecke,ShenyangYu,YueLi,EarlySilurian(Telychian)bryozoanreefsintheepeiricseaofSouthChina:Areheterotrophicmetazoanbuildupspromotedbyinternalwaves?.SedimentaryGeology(2018),doi:10.1016/j.sedgeo.2018.07.008 Photomicrographsofreeflimestonesofthelowerreefhorizon.(A)Fistuliporaframestone.(B)Close-upoftheboxinAshowingfistuliporidbryozoans.(C)Fistulipora-Asperoporaframestone.(D–E)Close-upsoftheboxesmarkedinDshowingdifferentbryozoans.NotethatsomeAsperoporacoloniesdevelopedonthetopoffenestellidbryozoans(redarrows).A=Asperopora,F=Fistulipora.
2018-11-01
A new protolepidodendrid lycopsid from the Middle Devonian of Hunan
Tiaomaphytonfuigen.etsp.nov.Xu,FuetWangfromtheMiddleDevonianTiaomachianFormation,Hunan,SouthChinaTheMiddleDevonianfloraofSouthChinaconstitutesakeycomponentofPalaeozoicflorasandischaracterisedasbeingdominantofendemicplants.However,thestudyoftheMiddleDevonianflorawasmainlybasedonmaterialsfromtheupperYangtzeregion,suchastheXichongFlorafromYunnanProvince,southwesternChina(YangtzeBlock).CentralHunan,especiallythepalaeogeographicCathaysiaBlock,thoughdevelopsnon-marineMiddleDevoniandeposits,well-describedplantfossilsthatcanbecomparedwiththosefromothercoevalfloraswererare.Itissignificantforunderstandingplantsevolution,comparingflorasandpalaeogeographytostudyMiddleDevonianflorafromHunanProvince. Recently,anewprotolepidodendridlycopsidisdescribedfromtheMiddleDevonianTiaomachianFormationofChangsha,Hunan,bytheworkgroupofprof.XUHonghe,AssociateProf.FUQiangandgraduatestudentWANGYaofromNanjingInstituteofGeologyandPalaeontology,ChineseAcademyofSciences.Theplanthasslenderstemandovalleafbase.Itsleaftrifurcatesintoalaminawiththreesegmentsinoneplanecurvingadaxiallyandaheelofsmalltipdownwardly.Thecentralsegmentisthelongest,whilstallthreesegmentsarecloseandparallelingarranged.Thesporangiumattachedadaxiallytothesporophyllbyapadisellipsoidalandovalinshapeandwithlongitudinaldehiscence.TheplantTiaomaphytonfuiwasnamedafteritslocalityTiaomajianTown. ThepresentplantTiaomaphytonfuifromtheMiddleDevonianofcentralHunan,whichpalaeogeographicallybelongstotheCathaysiaBlock,oneofthetwosub-regionsofthewholeSouthChinaPlate. ThestudygivesabetterunderstandingoftheMiddleDevonianfloraoftheCathaysiaBlockandhaspalaeogeographicimplicationstotheSouthChinaPlate.AfloristicdistinctionbetweentheCathaysiaandYangtzeblocksissuggestedanditisprobablycausedbythespecialpalaeogeographicpatternoftheSouthChinaPlate. ThispaperwillbepublishedrecentlyintheJournal“ReviewofPalaeobotanyandPalynology”. Paperinformation:XuH-H,FuQ,WangY.2018.AnewprotolepidodendridlycopsidfromtheMiddleDevonianofHunan,SouthChinaanditspalaeogeographicimplications.ReviewofPalaeobotanyandPalynology.256,63-69. https://doi.org/10.1016/j.revpalbo.2018.06.003
2018-11-01
New observations of Zosterophyllum sinense from the Lower Devonian of Guangxi
Zosterophyllumsinense(Zosterophyllopsida)fromtheLowerDevonianCangwuFormationofGuangxi,SouthChina:thetypespecimen(PB6477,left)andthereconstruction(right)Thezosterophyllopsid,animportantgroupoftheearlylandvascularplants,waswidespreadonanumberofpalaeocontinentsoftheEarlyDevonianandactsasadominantplantmemberoftheSouthChinaEarlyDevonianflora.MostpreviousstudieswerebasedonspecimensfromYunnan,whilstfewstudiesweregiventoLowerDevonianplantsfromGuangxi.Though,ZosterophyllumsinensewasreportedbyLiandCaiin1970s,moredetailedinformationwasobscure.Itissignificantforunderstandingplantsevolution,comparingfloarsandpalaeogeographytostudyzosterophyllosidsfromGuangxiProvince. Recently,ProfessorXUHongheandWANGYi,AssociateProfessorFUQiangandgraduatestudentWANGYaofromNanjingInstituteofGeologyandPalaeontology,ChineseAcademyofScienseshavere-observedthetypespecimensofZosterophyllumsinensefromLowerDevonianofGuangxiandcollectednewspecimensfromthesamelocality. Thisresearchcarriesafurtherstudyontherootingsystem,terminalspikesandsporangialdehiscecharacteristicsofZ.sinense,revisesitdiagnosisandreconstructsthisplant. Theplantwithtuftedhabitconsistsofthebelow-groundpart(rhizomearea)andtheabove-groundpart(axesandterminalspikes).Therhizomeareaisformedbydensemassesofaxesextendingtowardsseveraldirectionsandtheaxesabove-groundaresmoothandoftenbranchingK-shapedoranisotomousnear-ground.Spikecomprisesthecentralfertileaxisandlooselyandhelicallyarrangedsporangia.Thesporangiumispear-shapedorfan-shapedinfaceviewandfusiformtoovalinlateralview.Thesporangiumdehiscesintotwounequalsporangialvalvesandtheabaxialvalveislargerthantheadaxialone. Palaeogeographically,GuangxibelongedtotheCathaysiaBlock,asub-regionoftheSouthChinaBlock,whilepreviousLowerDevonianfloristicrecordsweremainlyfromYunnan,whichbelongedtotheYangtzesub-regionofthewholeSouthChinaBlock.Though,theCathaysiaandYangtzeblocksbelongedtoacontinentalterrane,therewasanepicontinentalseabetweenthetwoblocksduringthePalaeozoic.Plantfossilsinthisstudysuggestafloristicdistinctionbetweenthetwoblocks. ThispaperwillbepublishedrecentlyintheJournal“ReviewofPalaeobotanyandPalynology”,asbelow: Reference:WangY.,XuH-H,WangY,FuQ,2018.AfurtherstudyofZosterophyllumsinenseLiandCai(Zosterophyllopsida)basedonthetypeandthenewspecimensfromtheLowerDevonianofGuangxi,southwesternChina.ReviewofPalaeobotanyandPalynology.258,112–122.
2018-11-01
Graptolite biostratigraphy reveals the circumjacent distribution pattern of the Yichang Uplift
patialandtemporaldistributionoftheYichangUpliftStratigraphichiatusesofvariabletimeintervalswithintheRhuddaniantoearlyAeronian(Llandovery,Silurian)areidentifiedintheareaborderingEastChongqing,WestHubeiandNorthwestHunanincentralChina.Theirdistributionsuggestedtheexistenceofalocaluplift,traditionallynamedtheYichangUplift. ThediachronousnatureofthebasalblackshaleoftheLungmachiFormationcrossingdifferentbeltsofthisUpliftsignifiesthevariousdevelopingstagesduringtheupliftingprocess.ThepresentpaperbyProf.CHENXufromNanjingInstituteofGeologyandPalaeontology,ChineseAcademyofSciencesandcolleguesdefinethetemporalandspatialdistributionpatternoftheYichangUplift,whichmightbeoneoftheimportantcontrollingfactorsforthepreservationanddistributionoftheshalegasinthisregion. Thepresentworkisasisterstudytothepublishedpaper,“Stage-progressivedistributionpatternoftheLungmachianblackgraploliticshalesfromGuizhoutoChongqing,CentralChina”.ThesetwostudiesprovideacompleteOrdovician-SilurianblackshaledistributionpatternintheMiddleandUpperYangtze,aregionwiththemajorshalegasfieldsinChina. ThisresearchwaspublishedinScienceChinaEarthSciencesasacoverstory,anditwassupportedbyStrategicPriorityResearchProgramofChineseAcademyofSciences,theNationalNaturalScienceFoundationofChinaandtheNationalScienceandTechnologyMajorProjectofChina. Reference:ChenX,ChenQ,ZhenY,WangH,ZhangL,ZhangJ,WangW,XiaoZ.2018.CircumjacentdistributionpatternoftheLungmachiangraptoliticblackshale(earlySilurian)ontheYichangUpliftanditsperipheralregion.ScienceChinaEarthSciences,61:1195–1203.
2018-11-01
Middle Triassic ammonoids from Canada, biochronological and palaeobiogeographical implications
CanadahasanextensiverecordofTriassicmarinesedimentsdocumentingabundantammonoidfaunasofmidandhighpalaeolatitudes,rangingfromGriesbachiantolateRhaetian.AlongwiththematerialfromNevada(lowpalaeolatitude),BritishColumbiaprovidesanexcellentexamplefordiscussionsonammonoidpalaeogeographyandlatitudinalgradientoftaxonomicrichness. SomeAnisianammonoidsreportedfromBritishColumbiaforthefirsttimeRecently,Dr.JIChengfromNanjingInstituteofGeologyandPalaeontology,ChineseAcademyofSciencesandcolleaguefromSwitzerlandreportednewmaterialofAnisian(MiddleTriassic)ammonoidsfromBritishColumbiabasedonpopulatioanlapproachandrecognizedsixspecieswhichwereonlyfoundinNevadabefore. Theoccurrenceoflow-palaeolatituderestrictedspeciesinBCindicatesthatexchangesbetweenlow-andmid-palaeolatituderegionswereactuallymoresignificantthanpreviouslydocumented.ModeratelevelsofexchangeexistednotonlyduringmiddleAnisianbutalsoduringthelateAnisian.Thenewmateriallargelyimprovedthecorrelationofammonoidunitaryassociationzonesbetweenthetworegions. TheserevisedbiochronologicalcorrelationsindicatethatBCbiochronozoneswerenotnecessarilyoflargerdurationthanthosefromNevada.Alongwithincreasingsamplingefforts,BCbiochronozonestendeithertobeexactcorrelativeofNevadazones,ortointercalatebetweenthem.Therefore,thecommonviewthatgeographicallydifferentiatedevolutionaryratesoriginatesfromthelatitudinalgradientoftaxonomicrichnessdoesnotholdforAnisianammonoidfaunasalongthePalaeopacificmarginofNorthAmerica.Therelativelowerdiversityofammonoidinhigherlatitudeismostlikelyduetothelowcarbonatecontent,insteadofdifferentoriginationandextinctionrates. MiddleandupperAnisianrevisedammonoidzonationofnorth-easternBritishColumbiaThisresearchhasrecentlybeenonlinepublishedinPapersinPalaeontology. Paperinformation:ChengJiandHugoBucher.2018.Anisian(MiddleTriassic)ammonoidsfromBritishColumbia(Canada):biochronologicalandpalaeobiogeographicalimplications.PapersinPalaeontology.
2018-11-01
Hyoliths with pedicles illuminate the affinity with brachiopods
PedunculothecadianiaSun,ZhaoetZhugen.etsp.nov.fromtheChengjiangBiota,YunnanProvince,ChinaHyolithsareataxonomicallyproblematicgroupofPalaeozoiclophotrochozoansthatareamongthefirstshellyfossilstoappearintheCambrianperiod.Onthebasisoftheirdistinctiveexoskeleton,hyolithshavehistoricallybeenclassifiedasaseparatephylumwithpossibleaffinitiestothemolluscs,sipunculansorlophophorates–buttheirprecisephylogeneticpositionremainsuncertain. Recently,Dr.SUNHaijing,Prof.ZHAOFangchenandcolleaguesfromtheNanjingInstituteofGeologyandPalaeontology,ChineseAcademyofScienceswithDr.MartinSmithfromtheDurhamUniversity,describeaneworthothecidehyolithfromtheChengjiangLagerstatte(CambrianSeries2Stage3),Pedunculothecadiania,publishedinProceedingsoftheRoyalSocietyB:BiologicalSciences. ReconstructionofadultPedunculothecadianiainfeedingpositionThenewtaxonexhibitsanon-mineralizedattachmentstructurethatstrikinglyresemblesthebrachiopodpedicle–thefirstreportofapeduncularorganinhyoliths.Thisorganestablishesasessile,suspensionfeedingecologyfortheseorthothecides,and–togetherwithothercharacteristics(e.g.,bilaterallysymmetricalbivalveshellenclosingafiltrationchamberandthedifferentiationofcardinalareas)–identifieshyolithsasstem-groupbrachiopods. Thephylogeneticanalysisindicatesthatbothhyolithsandcrownbrachiopodsderivedfromatommotiidgrade,andthatthepediclehasasingleoriginwithinthebrachiopodtotalgroup.Shellmicrostructures,inparticular,the‘canaliculate’microstructureand‘punctae’,thosehavebeenaffordedgreatimportance–turnouttohavemultipleoriginsacrossthebrachiozoans. Identifyinghyolithsasstem-groupbrachiopodsnotonlyresolvescharacterpolaritywithinthegroupitself,thatPedunculothecaismoreprimitivethanhyolithidesandotherorthothecideswhichareunitedbythesecondarylossofapedicleandthemorphologyoftheirmetamorphicshell;butalsoindicatesaprofoundadaptivestrategychangeattheendoftheCambrian,thatthedramaticdeclineofstembrachiopodsandlinguliformswithahighmetabolicoverheadweresupplantedbytheradiationoflineagesexpertineconomicliving. Reference:SunH,SmithMR*,ZengH,ZhaoF*,LiG,ZhuM.2018Hyolithswithpediclesilluminatetheoriginofthebrachiopodbodyplan.Proc.R.Soc.B20181780.DOI:10.1098/rspb.2018.1780
2018-11-01
New progress made on Cupressaceae plant fossil from the Middle Jurassic Daohugou Biota in China
SomefossilspecimensofAustrohamiaacanthobracteafromtheDaohugoubiota TheCupressaceaeistheonlyconiferfamilythatdistributeinallcontinentsexceptforAntarctica,anditisespeciallyremarkableforthediversityofmorphology,species,andhabitatpreferenceexhibitedbyitsmembers.ThefossilrecordsuggeststhattheancestralgroupsofCupressaceaeoriginatedduringtheTriassic.Duringthemiddle-lateMesozoic,thediversityandgeographicaldistributionofCupressaceaearecrucialandtheancestorsofallsubfamiliesappearedanddifferentiated.However,detailedinvestigationsonmorphologyandanatomicalcharacteristicsoftheMesozoicCupressaceaetaxaarestillverylimitedcomparedwiththeirrichfossilrecord,whichimpedetheunderstandingoftheearlymorphologicaldiversityandevolutionofthemiddle-lateMesozoicCupressaceaeplants. Recently,aresearchteamoftheMesozoicplantsrepresentedbyDr.DONGChong,Prof.WANGYongdongandProf.YANGXiaojufromtheNanjingInstituteofGeologyandPalaeontology,ChineseAcademyofSciences(NIGPAS)providenewinsightintothewhole-plantreconstructionandphylogenyonAustrohamiaacanthobractea—aCupressaceaetaxonfromtheMiddleJurassicDaohugoubiotainnortheasternChina.Thestudyrevealedtheexquisitedetailsofthevegetativeshootsandleafcuticles,ovulateconesandinsituovules,pollenconesandinsitupollengrains,providingacompletesupplementarydepictiononthemorphologicalandanatomicalinformationofthisJurassiccypressplant.Theupdateresultwasrecentlypublishedin“InternationalJournalofPlantScience”,awell-knownscientificjournalpublishedinUniversityPressofChicagoinUSA. Whole-plantreconstructionofAustrohamiaacanthobractea. Austrohamia,theoldestmacrofossilrecordofCupressaceaewasoriginallyreportedfromtheEarlyJurassicintheArgentinaofthesouthernHemisphere.Inadditiontothetypespecies,Austrohamiaacanthobracteaisthesecondfossilrecordofthegenus.Theco-occurrenceofAustrohamiaintheJurassicofboththeSouthernandNorthernHemispheresappearstosuggestanintercontinentaldisjunctionbetweenGondwanaandLaurasia.A.acanthobracteaisthemostcommonspeciesamongtheplantfossilsfromtheDaohugoubiota.Theserichandwell-preservedfossilmaterialswithmanydetailsmakesittobeoneofthemostcompletelystudiedJurassicCupressaceaespecies. Inaddition,byusingthemorphologicalcladisticanalysis,theresearchersshowthatthetwospeciesofAustrohamiaformapolytomywiththeexpandedCunninghamioideaecladeThissupportstheoriginalinterpretationthatthegenusiscloselyrelatedtoCunninghamiaandCunninghamia-likefossils.ThisstudyisofgreatsignificanceforacomprehensiveunderstandingofancestorgroupsanddiversityofearlyCupressaceae. ReconstructedphylogenyforCupressaceae(left)andfiguresofbract-scalecomplexes(right).TheDaohugouLagerstatteiswellknownforitsrichandwell-preservedfossilinvertebrates,vertebratesandplants,andrepresentsadepositwithsometerrestrialelements.Incontrast,detailedstudiesonsystematicsanddiversityinsomekeyplantfossiltaxaofthisbiotaisverypoorlydocumented,thusneedsmoreandurgentcomprehensivelystudy.ThisnewresultbyDONGetal.willthuspromoteanddeepentheinvestigationofkeyplantfossilsintheDaohugoubiota. ThisstudywassupportedbytheStrategicPriorityResearchProgram(B)ofCASandtheNationalNaturalScienceFoundationofChina. Reference:Dong,C.,Wang,Y.D.,Yang,X.J.,Sun,B.N.,2018.Whole-PlantReconstructionandUpdatedPhylogenyofAustrohamiaacanthobractea(Cupressaceae)fromtheMiddleJurassicofNortheastChina.InternationalJournalofPlantScience,179(8),640-662.Doi:10.1086/699665.
2018-11-01
Chinese-led Team Shows Mass Extinction Happened in Geological “Instant”
It took less than 30,000 years, and maybe only thousands, to kill more than 90% of sea creatures and most land species, according to the most precise study ever published about the mass extinction marking the end of the Permian Period. A recent study published in the Geological Society of America Bulletin on September 19 suggests an answer.
2018-09-18
Fossils reveal diverse Mesozoic pollinating lacewings
Insect pollination played an important role in the evolution of angiosperms. Recently, a research group provide new insight into the niche diversity, chemical communication, and defence mechanisms of Mesozoic pollinating insects. This research was recently published in Nature Communications on September 17th, 2018.
2018-09-13
Chinese Fossils Reveal Middle-Late Triassic Insect Radiation
Scientists from China and the UK reported two Middle-Late Triassic entomofaunas, providing not only the earliest records of several modern insect elements, but also new insights into the early evolution of freshwater ecosystems.This study confirms that holometabolous and aquatic insects experienced extraordinary diversification about 237 million years ago. The research was published in Science Advances on September 5, 2018.
2018-09-05