This is a repository copy of Permian (Artinskian to Wuchapingian) conodont biostratigraphy in the Tieqiao section, Laibin area, South China.

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Article:

Sun, YD, Liu, XT, Yan, JX et al. (7 more authors) (2017) Permian (Artinskian to Wuchapingian) conodont biostratigraphy in the Tieqiao section, Laibin area, South China. Palaeogeography, Palaeoclimatology, Palaeoecology, 465 (A). pp. 42-63. ISSN 0031-0182

https://doi.org/10.1016/j.palaeo.2016.10.013

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1

Early-Middle Permian conodont biostratigraphy in the Tieqiao1

section,Laibinarea,SouthChina2

Y.D.Sun1,2*,X.T.Liu3,J.X.Yan1,B.Li4,B.Chen5,D.P.G.Bond6,M.M.Joachimski2,P.B.3

Wignall7,X.L.Lai1*4

1. Key Laboratory of Geobiology and Environmental Geology, China University of5

Geosciences,Wuhan430074,P.R.China6

2. GeoZentrum Nordbayern, Universität Erlangen-Nürnberg, Schlossgarten 5, 910547

Erlangen,Germany8

3. Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese9

AcademyofSciences,Qingdao266071,China10

4. Key Laboratory of Marine Mineral Resources, Guangzhou Marine Geological Survey,11

MinistryofLandandResources,Guangzhou510075,China12

5.StateKeyLaboratoryofPalaeobiologyandStratigraphy,NanjingInstituteofGeology13

andPalaeontology,39EastBeijingRoad,Nanjing210008,R.P.China14

6.DepartmentofGeography,EnvironmentandEarthSciences,UniversityofHull,HullHU615

7RX,UK16

7.SchoolofEarthandEnvironment,UniversityofLeeds,LeedsLS29JT,UK 17

*Correspondingauthor:E-mail:yadong.sun@cug.edu.cn(Y.D.Sun);xllai@cug.edu.cn(X.L.18

Lai)19

20

2

Abstract21

Permian strata from the Tieqiao section (Jiangnan Basin, South China)22

contain several distinctive conodont assemblages. Early Permian (Cisuralian)23

assemblagesaredominatedbythegeneraSweetognathus,Pseudosweetognathus24

and Hindeodus with rare Neostreptognathodus and Gullodus. Gondolellids are25

absent until the end of the Kungurian stage—in contrast to many parts of the26

worldwheregondolellidsandNeostreptognathodusarethedominantKungurian27

conodonts.AconodontchangeoverisseenatTieqiaoandcoincidedwithariseof28

sealevel inthelatestKungurian:thepreviouslydominantsweetognathidswere29

replacedbymesogondolellids. TheMiddle andLatePermian (Guadalupian and30

Lopingian Series) witnessed a dominance of gondolellids (Jinogondolella and31

Clarkina),thecommonpresenceofHindeodusanddecimationofSweetognathus.32

Twenty one main and six subordinate conodont zones are recognized at33

Tieqiao, spanning the lowerArtinskian to lowermostWuchiapingianStage.The34

main (first occurrence) zones are, in ascending order by stage: the35

Sweetognathus(Sw.)whitei,Neostreptognathodus(N.)pequopensis-Sw.toriyamai,36

andSw.asymmetrican.sp.ZonesfortheArtinskian;theN.prayi,Sw.guizhouensis,37

Sw.iranicus,Sw.adjunctus,Sw.subsymmeticus,Sw.hanzhongensis,Mesogondolella38

(M.) idahoensis andM. lamberti Zones for theKungurian; the Jinogondolella (J.)39

nankingensis Zone for the Roadian; the J. aserrata Zone for the Wordian; the J.40

postserrata,J.shannoni,J.altudaensis,J.prexuanhanensis,J.xuanhanensis,J.granti41

and Clarkina (C.) hongshuiensis Zones for the Capitanian and the C. postbitteri42

3

ZoneforthebaseoftheWuchiapingian.Thesubordinate(interval)zonesarethe43

Pseudosweetognathuscostatus,Pseduosweetognathusmonocornus,Hindeodus(H.)44

gulloides, Pseudohindeodus ramovsi, Gullodus sicilianus, Gullodus duani and H.45

excavatesZones.46

Inaddition, threenewspecies,Gullodus tieqiaoensisn.sp.,Pseudohindeodus47

ellipticae n. sp. and Sweetognathus asymmetrica n. sp. are described. Age48

assignmentsforlesscommonspeciese.g.,Pseudosweetognathusmonocornusare49

reassessedbasedonarichconodontcollection.50

Key words: conodont, Permian, biostratigraphy, Cisuralian, Guadalupian,51

Kungurian,SouthChina52

53

4

1.Introduction54

ConodontsareimportantindexfossilsinthePalaeozoicandTriassic,dueto55

their high speciation rates, geographically widespread distribution and in part56

high abundance in marine sediments. Conodont biostratigraphy provides the57

best method for high-resolution, supra-regional correlations of Permian strata,58

becauseotherkey taxa suchas ammonoidsareoften scarce inmany locations,59

whilst foraminifers and brachiopods are generally long ranging and facies60

controlled and thus less useful for age diagnosis. As a consequence, Permian61

conodonttaxonomyandbiostratigraphyhavebeenthetopicsofextensivestudy62

since the 1950s (e.g., Youngquist et al., 1951; Clark andBehnken, 1971; Ritter,63

1986;WardlawandGrant,1990;Meietal.,1994a;Wardlaw,2000;Nestelletal.,64

2006;Lambert et al., 2010; Shenet al., 2012).The importanceof conodonts in65

stratigraphy is exemplified by their use at Global Boundary Stratotype Section66

and Points: as of 2016, conodonts define of the bases of all but one of the 2967

stagesbetweenthePragian(LowerDevonian)andRhaetian(UpperTriassic),1768

ofwhichhavebeenratifiedbytheInternationalCommissiononStratigraphy.69

Thediversity of Permian conodonts is generally low in comparison to that70

observed for other time periods, with typically less than five genera and two71

dozensofspeciesoccurringinanygivenPermianstage.Conodontzonesarealso72

relativelylongforsomeintervals.Forinstance,thoughsubstantialinvestigations73

have been carried out in West Texas (e.g., Wardlaw, 2000; Nestell et al., 2006;74

Nestell and Wardlaw, 2010a; Wardlaw and Nestell, 2010), only one standard75

5

conodont zone has been established for the Roadian and Wordian stages76

(Henderson et al., 2012). This reflects a true low point in the diversity of77

conodontsduringtheir longevolutionaryhistory.Afurthercomplicationisthat78

minor changes in Permian conodont morphology require a careful taxonomic79

examination of different species.New species are rarely reported from regions80

otherthanWestTexasandSouthChina,perhapsowingtoadecreaseinresearch81

effortandasubstantiallossofexpertiseinrecentyears.82

Establishinga robustbiostratigraphic scheme indifferentareas isessential83

forsupra-regionalcorrelation.Permianconodontshavebeenbeststudiedinthe84

UralsofRussia (EarlyPermian),WestTexas (MiddlePermian)andSouthChina85

(Late Permian and the Permo-Triassic boundary) (e.g., Chuvashov et al., 1990;86

Meietal.,1994b;Zhangetal.,1995;Wardlaw,2000;Lambertetal.,2002;Jianget87

al., 2007; Nestell and Wardlaw, 2010b). The Early to Middle Permian of South88

China has attracted comparatively little research attention and is less89

systematicallystudied.90

This study presents a high-resolution conodont record for the Tieqiao91

section,Guangxi,SouthChina.Newdata,spanningtheArtinskian(EarlyPermian)92

to the early Wuchiapingian (Late Permian), substantially improve existing93

records of the section, first described two decades age in the context of the94

Capitanian-Wuchiapingian(Guadalupian-Lopingian)transition(Meietal.,1994c;95

Wang,2002).96

6

2.GeologicalSetting97

TheYangtzeregionwasalargeisolatedplatformsituatedwithinthePermian98

equatorial Tethys (Fig. 1) with extensive carbonate deposition and diverse99

sedimentaryfacies.Itisanideallocationforconodontstudies.TheLaibinareais100

located in the JiangnanBasin towards the southwesternmargin of theYangtze101

Platform(WangandJin,2000).Aseriesofsuperbsectionsareexposedalongthe102

banks of Hongshui River (Shen et al., 2007) and these have been103

comprehensively studied for the Capitanian-Wuchiapingian transition (e.g.,Mei104

etal.,1994c;Wangetal.,2004;Jinetal.,2006;Wignalletal.,2009b;Chenetal.,105

2011). 106

The Permian strata of the region consist of thick Early Permian platform107

carbonates,subordinateMiddlePermianslopeaswellasbasinalcarbonatesand108

cherts. Late Permian rocks are geographically more variable, including coal109

seams,reefbuild-upsandradiolariancherts(Shaetal.,1990;Shenetal.,2007;110

Qiuetal.,2013).111

ThestudiedsectionatTieqiao(23°42.733'N,109°13.533'E)isexposedon112

thenorthernbankoftheHongshuiRiver,southeastofthetownofLaibin(Figs.1,113

2).ThePermianstratameasure1307mthickandcomprisetheMaping,Chihsia,114

Maokou, Heshan, Wuchiaping and Talung Formations, spanning the earliest115

Permian (Asselian) to the Permian-Triassic boundary (Sha et al., 1990). The116

sectionisveryfossiliferouswithforaminifers,calcareousalgae,crinoids,sponges117

7

andcoralsbeingprolificallyabundant(e.g.,WangandSugiyama,2000;Bucuret118

al., 2009; Zhang et al., 2015), whilst bivalves and ammoinods occur less119

frequently.Well-preservedZoophycostracefossilsarealsoabundant(Gongetal.,120

2010).121

Sha and colleagues (1990) pioneered the study of the Tieqiao section and122

subdividedthesectioninto15Membersand139Beds.Ourstudyfollowsthese123

subdivisions (Figs. 3-5) for consistency and focuses on the stratigraphy and124

conodont zonation of the Chihsia and Maokou formations (Bed 1 to Bed 109).125

TheChihsaFm.generallyrecordsdepositioninacarbonaterampsetting,whilst126

theMaokouFm.comprisesslope tobasin transition facies.The two formations127

are overall 710 m thick and range from the Sakmarian (?) to the128

Capitanian-Wuchiapingianboundary(Figs.3-5).129

3.MaterialsandMethods130

The section was sampled over four field campaigns between 2005-2010.131

During the springof2010, thewaterof theHongshuiheRiver fell to its lowest132

levelofthepasttenyearsduetoaseveredrought,whichallowedustodescribe133

and sample several normally submerged parts of the section (e.g., Bed 17 and134

Bed112).Atotalof374rocksampleswerecollectedwithasamplingresolution135

of~1-2mformostpartsofthesection.Chertsandgrainstonesbearingabundant136

corals and fusulinid foraminifers were avoided during sampling due to137

complications in conodont extraction and low conodont yields. Each sample138

8

weighedbetween2.5and8kg.139

Threehundredandelevensampleswereprocessedinthemicropaleontology140

laboratory at China University of Geosciences (Wuhan) and 63 samples were141

processed at the GeoZentrum Nordbayern, Universität Erlangen-Nürnberg. All142

samplesweredissolvedusing7-10%dilutedaceticacid,wetsievedandair-dried.143

Theinsolubleresidueswereseparatedbyusingheavyliquidfractionation(Jiang144

etal.,2007).Conodontspecimenswerehandpickedusingabinocular.Conodonts145

fromTieqiaoaregenerallywellpreservedwithcolouralternationindexranging146

from1.5to2.5.Atotalof8733specimenswereobtainedfromsampleprocessat147

Wuhanlabandabout~3000specimenswasrecoveredatErlangen.Resultsfrom148

bothlaboratorieswerecrosschecked.149

4.StratigraphyandConodontZonation150

4.1Sakmarian(?)151

The lowermost part of the studied section (Beds 1 to 16, Chihsia Fm.)152

consists mainly of thin-to-medium bedded dark-grey bioclastic micrites, marls153

and black shales (Fig. 2). Brachiopods, gastropods, crinoids, bryozoans and154

spongesarethemostabundantfossils.Ageassignmentforthispartofthesection155

is controversial. Sha et al. (1990) suggested anAsselian age for theunderlying156

MapingFm.andreportedtheoccurrenceofthefusulinaceanEoparafusulinasp.,157

Nankinellasp.,Pamirinasp.,Staffellasp.andPseudofusulinasp.fromBed1toBed158

16,implyingapossibleSakmarianagefortheunit.Meietal.(1998)inferredthis159

9

unittobeof“Longlinian”age—aChineseequivalentoftheArtinskianbyoriginal160

definition (Sheng and Jin, 1994; Jin et al., 1997), now re-defined as Sakmarian161

(Fig. 24.1 in Henderson et al., 2012). Based on consideration of all published162

fossilmaterials,Shenetal.(2007)tentativelyassignthispartofthesectiontothe163

Artinskian.164

Few conodonts were recovered from this part of the section, despite great165

efforts. Many ramiform elements were recovered from Bed 8, but none is166

age-diagnostic.Thepreciseageofthisunitthereforeremainsunresolved.167

4.2Artinskian168

Beds 17 to 26 consist mainly of dark-grey to grey bioclastic pack- and169

grainstones. The conodont assemblage is dominated by Sweetognathus whitei170

andaffinitivespeciesandthusindicatesanArtinskianage.Neostreptognathodus171

andHindeodusarerarewhilstgondolellidsareabsent.ThebaseoftheArtinskian172

stage cannotbepreciselydefinedbecause the first appearancedatum(FAD)of173

Sweetognathus whitei cannot be ascertained due to the inaccessibility of the174

submerged lowerpartofBed17andtheabsenceofdiagnosticconodonts from175

bedsbelowthislevel.Inascendingorder,threeconodontzoneswereestablished176

fortheArtinskian. 177

1).SweetognathuswhiteiZone178

Thelowerlimitofthiszoneisnotdefined.Theupperlimitisdefinedbythe179

FAD of Sweetognathus (Sw.) toriyamai and Neostreptognathodus ex gr.180

10

pequopensis.181

Sw. whitei was one of the most cosmopolitan conodonts during the Early182

Permian (Meietal.,2002). It isknowne.g. fromNorthandSouthChina, Japan,183

U.S.A., Canada and Colombia. (Rhodes, 1963; Igo, 1981; Orchard, 1984; Ritter,184

1986;DingandWan,1990; Jietal.,2004)and isconsideredagoodmarker for185

thebaseofArtinskian. 186

2).Neostreptognathodusexgr.pequopensis-SweetognathustoriyamaiZone187

Lower limit: FAD of Sw. toriyamai and Neostreptognathodus (N.) ex gr.188

pequopensiswithbothtaxafirstoccurringatthesamelevel.Upperlimit:FADof189

Sw. asymmetrica n. sp. The FAD of Sw. bogoslovskajae occurs in this zone. Sw.190

bogoslovskajae is known to co-exist with N. pequopensis in Nevada and has a191

range restricted to the upper “Baigendzhinian” (equivalent to uppermost192

Artinskian to lower Kungurian) (Ritter, 1986). Wang (2002) reported the193

occurrenceofSw. variabilis in this zone (inBed18ofTieqiao).Wehave found194

morphotypes which are similar to Sw. variabilis but the specimens are not195

sufficientlywell-preservedtomakeanidentification. 196

3).Sw.asymmetrican.sp.Zone197

Lower limit: FAD of Sw. asymmetrica n. sp. Upper limit: FAD of198

Neostreptognathodusprayi.HindeoduscatalanoiandSw.cf.windico-occurinthis199

zone. This zone probably straddles the Artinskian-Kungurian boundary due to200

theabsenceoftheN.pnevizoneatTieqiao.201

11

4.3Kungurian202

Kungurianrocks,spanningfromBed27tothelowerpartofBed109,consist203

mainly of medium-to-thick bedded fossiliferous pack- and grainstones with204

commonchertnodulesinthelowerpart.Mediumtothinbeddedlimemudstones205

andwackestonesweregraduallydevelopedhigherintheKungurianstrata,witha206

notable shift in fossil assemblages from a bryozoan- and calcareous207

algae-dominated shallow water facies (Beds 89-99) to a sponge spicule and208

radiolarianrichdeeperwaterfacies(Beds100-111). 209

TheconodontbiostratigraphyofthebasalKungurianstagehasbeenamatter210

of debate (Wang et al., 2011). Kozur et al. (1995) suggested the cline211

Neostreptognathoduspequopensis-N.pnevi tobesuitable foradefinition for the212

Artinskian-Kungurian boundary. Mei et al. (2002) proposed the FAD of N.213

pequopensis or Sw. guizhouensis to define the base of the Kungurian whereas214

Chuvashovetal. (2002) formallyproposed theFADofN.pnevi asdiagnosticof215

the base of the Kungurian, a definition that has been generally accepted216

(Hendersonetal.,2012).However,duetotheabsenceofN.pneviatTieqiao,we217

alternativelysuggestthebaseoftheKungurianbedefinedbytheFADofN.prayi.218

EightconodontzoneswereestablishedfortheKungurian,describedinascending219

orderbelow:220

4).NeostreptognathodusprayiZone221

Lower limit: FAD of Neostreptognathodus prayi. Upper limit: FAD of Sw.222

12

guizhouensis.TheN.prayiZoneisthesecondoldestzoneoftheKungurianinthe223

standardPermianconodontzonation(Hendersonetal.,2012)andsotheN.prayi224

zoneatTieqiaodoesnotindicatethe“true”earliestKungurian(Fig.6).Sw.clarki,225

aspeciesmostcommonlyseeninthelateArtinskian(BeauchampandHenderson,226

1994),alsooccursinthiszone.Thefirstoccurrence(FO)ofSw.clarkiatTieqiao227

isonlyslightlylowerthanthatofSw.guizhouensis.228

5)Sw.guizhouensisZone229

Lowerlimit:FADofSw.guizhouensis.Upperlimit:FADofSw.iranicus.Except230

for in the lower part of this ~180 m thick conodont zone, conodonts are231

relatively rare. The long-ranging species Pseduosw. costatus is the only species232

thatwassparselyrecoveredintheupperpartofthiszone. 233

6)Sw.iranicusZone234

Lowerlimit:FADofSw.iranicus.Upperlimit:FADofSw.subsymmetricus.As235

withtheSw.guizhouensisZone,bothconodontdiversityandabundancearevery236

low.Amajor stratigraphic complication at this level of the section is thatBeds237

76-88areatectonicrepetitionofolderbeds(alsoseeShaetal.,1990). 238

7)Sw.adjunctusZone239

Lowerlimit:FADofSw.adjunctus.Upperlimit:FADofSw.subsymmetrics.Sw.240

cf. paraguizhouensis appears in this zone. Sha et al. (1990) reported the241

occurrenceof“Neogondolella”bisselliinthiszone(Bed91).However,“N”.bisselli242

isanolderspecieswhichoftenco-occurredwiththeArtinskianSw.whiteigroup243

13

(e.g., Behnken, 1975; Clark et al., 1979;Orchard, 1984;Wang, 1994;Mei et al.,244

2002). The occurrence of bisselli obviously contradicts a Kungurian age of the245

hoststrataandalsoisnotconfirmedbyourdataset.246

Sw. adjunctus is also known from the uppermost Victorio Peak Formation247

fromTexasandtheupperPequopFormationfromNevada,USA(Behnken,1975)248

as well as from south-central British Columbia, Canada (Orchard and Forster,249

1988): All of these occurrences are dated to be of late Leonardian age in the250

Permianregionalstratigraphy(=middletolateKungurian).Becauseofthewide251

distribution of Sw. adjunctus, this zone therefore has high potential for252

super-regionalcorrelation.253

8)Sw.subsymmetricusZone254

Lower limit: FAD of Sw. subsymmetricus. Upper limit: FAD of Sw.255

hanzhongensis. This zone correlates to the Kungurian “M. siciliensis-Sw.256

subsymmetricus”zoneinsouthernGuizhou(Meietal.,2002).257

Sw. subsymmetricus is well known from the Kungurian of Guizhou and258

GuangxiinSouthChina,aswellasfromThailandandOman(Meietal.,2002and259

this study; Henderson and Mei, 2003; Metcalfe and Sone, 2008; Burrett et al.,260

2015).TheassertionthatSw.subsymmetricusisrestrictedtotheRoadian(Kozur,261

1993)isincorrect.262

9)Sw.hanzhongensisZone263

Lowerlimit:FADofSw.hanzhongensis.Upperlimit:FADofM.idahoensis.The264

14

FAD of Pseudohindeodus augustus and Pseudohindeodus ramovsi occurs in the265

middle part of this zone. A turnover in the dominant conodont fauna initiated266

during this zone. Hindeodus becomes abundant whilst the abundance and the267

diversityofSweetognathusdecreases.Hindeoduspermicus,H.gulloidesandH.aff.268

wordensisalloccurinthiszone. 269

10)MesogondolellaidahoensisZone270

Lowerlimit:FADofM.idahoensis.Upperlimit:FADofM.lamberti.Conodont271

faunaschange fromHindeodus-Pseduohindeodus-Sweetognathus-dominatedand272

gondolellid-freeassemblagestogondolellid-dominatedassemblagesinthiszone273

(Bed109).Thisshiftinconodontassemblagecoincideswithalithologicalchange274

fromthick-andmedium-beddedwackestonestomorecherty,medium-tothin-275

beddedwacke-andcarbonatemudstones.276

11)M.lambertiZone277

Lower limit: FAD of M. lamberti. Upper limit: FAD of J. nankingensis.278

CarbonateoftheM.lambertiZone(Beds110-111)aremorethinlybeddedwith279

an increasing abundance of sponge spicules and radiolarian tests, indicating280

deepeningandarelativesealevelriseinthelatestKungurian.281

4.4Roadian282

TheRoadianstrataconsistoflessthan5mthickfinelylaminatedandthinly283

bedded carbonatemudstones starting at the topofBed111 (Fig. 2B).Amajor284

sea-levelriseisknownfromtheEarly-MiddlePermiantransitionandismanifest285

15

at Tieqiao by a transition to thinly bedded radiolarian cherts by Bed 112286

(Wordianage).Bythistime,deep,basinalsedimentationwasestablishedinthe287

region. The minor thickness of the Roadian strata may be attributed either to288

condensationduring this sea level rise or tohiatus resulting in a lossof strata289

(duetosuddenlossofcarbonateproductionbelowthecarbonatecompensation290

depth).Onlyoneconodontzoneisrecognized.291

12)JinogondolellanankingensisZone292

Lower limit: FAD of J. nankingensis. Upper limit: FAD of J. aserrata.293

Pseudohindeodusramovsiareabundant.Fine lamination intheupper(Roadian)294

partofBed111indicatesminorbioturbation.295

4.5Wordian296

WordianstrataarepresentedbyBed112tolowermostpartofBed116.The297

sediments consist of thinly bedded radiolarian cherts in the lower part (Beds298

112-113), thickly bedded bioclastic wacke- and packstones in the middle (Bed299

114, also known as “the Great White Bed”) and alternation of cherts and lime300

mudstonesintheupperpart(Bed115-116).Oneconodontzoneisrecognized.301

13)J.aserrataZone302

Lowerlimit:FADofJ.aserrata.Upperlimit:FADofJ.postserrata.TheFADofJ.303

palmata occurs at the same level as the FAD of J. aserrata. This is generally304

consistent with the record in west Texas where the FAD of J. palmata was305

reported very close to the FAD of J. aserrata (Nestell and Wardlaw, 2010a).306

16

Severalspecies,suchasJ.errata,GullodusduaniandthelongrangingspeciesSw.307

hanzhongensis and Pseudohin. ramovsi appear in the middle-upper part of this308

zone. 309

4.6Capitanian310

TheCapitanian(Beds116-119)isthemostintensivelystudiedintervalinthe311

Laibin area (Mei et al., 1994c; Jin et al., 2006; Chen et al., 2009;Wignall et al.,312

2009b).Strataofthisageconsistofmediumbeddedalternatingchertsandlime313

mudstones in the lower part (Beds 116-118) overlain by pack- to grainstones314

(LaibinLimestoneMember,Bed119).Hereweonlygiveabriefdescriptionofthe315

conodontzonesofthisstagesincetheyhavebeenwellstudied.316

14)J.postserrataZone317

Lowerlimit:FADofJ.postserrata.Upperlimit:FADofJ.shannoni. 318

15)J.shannoniZone319

Lowerlimit:FADofJ.shannoni.Upperlimit:FADofJ.altudaensis.320

16)J.altudaensisZone321

Lowerlimit:FADofJ.altudaensis.Upperlimit:FADofJ.prexuanhanensis.This322

interval is characterized by higher extinction rates as well as the onset of323

Emeishanvolcanism(Wignalletal.,2009a;Sunetal.,2010).Lossesincludemany324

foraminifers,calcareousalgae in theequatorialrealmandmanybrachiopods in325

the boreal realm (Bond et al., 2010; Bond et al., 2015). Though there are no326

17

obvious lithological changes in the J. altudaensis Zone at Tieqiao, the last327

appearances of several long-ranging conodonts, such as Gullodus duani, Sw.328

hanzhongensisandPseudohind.ramovsi,areallrecordedinthiszone.329

17)J.prexuanhanensisZone330

Lower limit: FAD of J. prexuanhanensis. Upper limit: the FAD of J.331

xuanhanensis.ThiszonehasnotbeenrecognizedinwesternTexas(Lambertetal.,332

2002).However,itisalsodistinguishableintheTieqiao(Guangxi,thisstudy)and333

atDukou(Sichuan,Meietal.,1994a)sections.IncondensedsectionsinGuizhou,334

the J.prexuanhanensis zone isoftencombinedwith theyounger J. xuanhanensis335

zoneastheJ.prexuanhanensis-J.xuanhanensisassemblagezone(Sunetal.,2010).336

Sw. fengshanensis occurs in this zone. Sw. fengshanensis was established in337

the lateCapitanianstrataatFengshan,northwesternGuangxi(Meietal.,1998).338

At thePenglaitansection,Sw. fengshanensis spans fromtheupper J.postserrata339

zonetothelowerJ.xuanhanensiszone,representingthelastintheevolutionary340

lineageofsweetognathidsinSouthChina(Meietal.,2002).341

18)J.xuanhanensisZone342

Lower limit: FAD of J. xuanhanensis. Upper limit: FAD of J. granti. Many343

maturemorphotypesofJ.shannonioccurinthelowermostpartofthiszoneand344

are very similar to their counterparts from West Texas (Lambert et al., 2002;345

WardlawandNestell,2010).Volcaniclasticmaterialstartstobedepositedduring346

thiszoneandbecomesmorecommonintheoverlyingJ.grantiZone,presumably347

18

corresponding to the large scale of explosive eruptions of the Emeishan Traps348

(e.g.,Sunetal.,2010).349

19)J.grantiZone350

Lower limit: FAD of J. granti. Upper limit: FAD of Clarkina hongshuiensis.351

Conodontsareprolificallyabundantinthiszonewithatypicalyieldrateof~100352

specimensperkgrock.353

20)ClarkinahongshuiensisZone354

Lowerlimit:FADofC.hongshuiensis.Upperlimit:FADofC.postbitteri.355

4.7Wuchiapingian356

The early Wuchiapingian (Bed 120) is characterized by deposition of357

extensivebeddedchertswithintercalatedpinkishlimestonelenses.Evidencefor358

a relative sea level fall towards the end of Wuchiapingian is indicated by a359

reductionofchertthicknessup-sectionwithcarbonatesedimentationincreasing.360

Eventually,thisbasinalsettingevolvedintoaspongereeffacies(Beds124-132)361

inthemiddle-lateWuchiapingianlackingconodonts.Clarkinatranscaucasicawas362

found in Bed 134. One conodont zone is established for the earliest363

WuchiapingianatTieqiao:364

21)ClarkinapostibitteriZone365

Lowerlimit:FADofC.postbitteri.Upperlimit:notdetermined.366

5.Subordinatezonesandreassessmentforageassignmentsofrarespecies367

19

Seven subordinate zones are established at Tieqiao, representing interval368

zonesbasedonoccurrencesof longrangingspecies.Thesubordinatezonesare369

less effective for stratigraphic correlation but can provide a valuable reference370

forcaseswhenasingleconodontassemblageisobtainedfromanage-ambiguous371

lithologic unit (e.g., Burrett et al., 2015). In the following section, we first372

describe therangesof thesesubordinatezones in theTieqiaosection, followed373

by comments on the range of the zonal species. A correlation with the main374

conodontzones isshown in figure.6.Note that therangeof thespeciescanbe375

muchlongerthantherespectivezone. 376

1)Pseudosweetognathus(Pseudosw.)costatusIntervalZone 377

Lower limit: FAD of Pseudosw. costatus. Upper limit: FAD of Pseudosw.378

monocornus. ThePseudosw. costatus Zone spans the earlyArtinskian tomiddle379

Kungurian(Bed19toBed94).Elementsof long-rangingspeciesH.minutusare380

abundantinthelowerpartofthiszoneandthereisasingleoccurrenceofH.aff.381

catalanoiinthelowermost.382

Pseudosweetognathuscostatuswasestablished inArtinskianstrataofSouth383

China (Wang et al., 1987) and also reported from Thailand, co-existing with a384

typicalKunguriantaxonSw.subsymmetricus(MetcalfeandSone,2008).Ourdata385

confirm former observations and indicate that the range of Pseudosw. costatus386

extends from the Artinskian Sw. asymmetrica n. sp. Zone to the Kungurian Sw.387

adjunctus Zone. In the middle Kungurian, Pseudosw. costatus was replaced by388

20

Pseudosw.monocornus.389

2)PseudosweetognathusmonocornusIntervalZone390

Lowerlimit:FADofPseudosw.monocornus.Upper limit:FADofH.gulloides.391

ThiszonecomprisesBed94toBed102atTieqiao,andisoflateKungurianage. 392

Li et al. (1989) established the species Pseudosweetognathus monocornus393

(under the genus “Sichuanognathodus”) from the upper part of Maokou Fm. at394

Shangsi.AlateranddetailedstudyofthesamesectionreportedaJinogondolella395

andHindeodusdominatedfaunawhichindicatesanearlyCapitanianageforthe396

upperMaokouFm.(Sunetal.,2008). 397

Pseudosweetognathusmonocornus is found in theupperpartofChihsiaFm.398

and lower part of Maokou Fm. at Tieqiao and here is reassigned a399

middle-Kunguriantoearly-Roadianage.Thisspeciesonlyoccurredwithshallow400

water, high energy assemblage composed of calcareous algae, corals and401

foraminifers found in thickly bedded bioclastic pack- and grainstones.We thus402

speculate that theoccurrenceofPseudosw.monocornusmightbe facies-related,403

anditspresenceinWordiantolowerCapitanianstrataelsewhere(Lietal.,1989)404

cannotbeexcluded.405

3)HindeodusgulloidesIntervalZone406

Lowerlimit:FADofH.gulloides.Upperlimit:FADofPseudohindeodusramovsi.407

This zone occupies Bed 102 and correlates to the middle part of Sw.408

hanzhongensiszone,representingaLateKungurianage.409

21

The species H. gulloides Kozur and Mostler, 1995, ranges from upper410

Kungurian to Roadian. In northeast Thailand, H. gulloides occurs at an411

age-equivalent level as in South China and co-existed with a typical late412

Kungurian assemblage which consists of species Mesogondolella siciliensis,413

Pseudohindeodus oertlii (= angustus) and Sw. subsymmetricus (Burrett et al.,414

2015). In west Texas, the species was recovered from the upper part of Road415

CanyonFm.,representingalateRoadianage(KozurandMostler,1995).416

4)PseudohindeodusramovsiIntervalZone 417

Lower limit: the FAD of Pseudohindeodus ramovsi. Upper limit: the418

occurrence of Gullodus sicilianus. This zone spans from Bed 103 to Bed 115,419

representingalatestKunguriantoWordianage.420

The species Pseudohindeodus ramovsi Gullo and Kozur, 1992 has a much421

longer range than the Interval Zone. Wardlaw (2000) reported sporadic422

occurrences of this species from the Kungurian to Capitanian. Our data are423

consistent with Wardlaw (2000), suggesting that Pseudohindeodus ramovsi424

spanned fromthe lateKungurianSw.hanzhongensis to themiddleCapitanian J.425

altudaensisZone.426

AnotherassociatespeciesinthiszoneisPseudosw.augustus(Igo,1981).This427

specieshasbeenreportedfromcoevalKungurianstratainJapan(Igo,1981;Shen428

et al., 2012), but can also occur inmucholder strata such as in theArtinskian429

(OrchardandForster,1988).430

22

5)GullodussicilianusIntervalZone 431

Lowerlimit:FOofG.sicilianus.Upperlimit:FADofGullodusduani.Thiszone432

coversthemiddlepartofBed115,representingamiddle-lateWordianage.433

Gullodus sicilianus (Bender and Stoppel, 1965) ranges from the Roadian to434

Wordian(Kozur,1993). It isa rare taxon that isknownmostly fromtheTethys435

realmduringtheWordian(Kozur,1995).436

6)GullodusduaniIntervalZone437

Lower limit: FAD of Gullodus duani. Upper limit: prolific occurrence of H.438

excavatus. This zone comprises Bed 115 to Bed 118, covering much of the439

Capitanian. An associated taxon Hindeodus catalanoi ranges through the upper440

partofthiszone.ThoughGulloandKozur(1992)assignedaWordianageforH.441

catalanoi, this form is found in the Capitanian at Tieqiao, suggesting a longer442

rangeofthespeciesthanitsoriginaldefinition.443

Gullodus duani Mei et al. 2002 is a rather rare species in the Guadalupian.444

ThisspecieswasoriginallyrecoveredfromtheMaokouFm.fromGuangxiandis445

onlyknownfromSouthChina.AtTieqiao,thisspeciesisknownfromuppermost446

WordiantomiddleCapitanianstrata.447

7)H.excavatusIntervalZone448

Lower limit: the prolific occurrence of H. excavatus. Upper limit: FAD of C.449

postbitteri (the Capitanian-Wuchiapingian boundary). At Tieqiao, this zone is450

23

representedbytheLaibinLimestoneMember(Bed119)ofalateCapitanianage.451

Hindeodusexcavatus isanother long-rangingspecies in thePermian,but its452

useasazonalfossilderivesfromitsprolificabundanceinthelateCapitanian.453

6.Systematicpalaeontology454

GenusGullodusKozur,1993455

Emended diagnosis: Spathognathodiform elements with a medium to long456

anterior blade and a posteriorly positioned, strongly expanded basal cavity.457

Denticles occur on the blade and above the basal cavity and are inmost cases458

without ornamentations. Denticles are generally 10-15 in number and those459

above the basal cavity can be expanded and form a carina-like structure or460

narrowtransverseridges.Smallcoalesceddenticlesaresometimesdevelopedon461

theanterioredgeformingan“anteriorblade”.Length/heightratioisbetween1.5462

and3.Basal cavities aregreatly expanded,non-ornamentedandoccupy1/3 to463

2/3ofthefullbody.464

Remarks:thediagnosisofthisgenus(Kozur,1993)shouldbeemendedbecauseit465

is often hard to differentiate between Gullodus and Hindeodus. The emended466

diagnosis also includes wider variability of Gullodus species. Key differences467

betweenGullodus andHindeodus are theshapeandpositionof thebasal cavity468

and the length/height ratio: Hindeodus has a more centrally positioned basal469

cavity and lower length/height ratio. A key difference between Gullodus and470

Sweetognathus is that denticles of Gullodus are not ornamented while those of 471

24

Sweetognathus develop nodes. Gullodus can be differentiated from472

Pseudohindeodus because the basal cavity of the latter is more (horizontally)473

expanded and ornamented with a surface apron and occupies!2/3 of the full474

elementlength.475

Based on the revised diagnosis, Gnathodus sicilianus Bender and Stoppel,476

1965 should remain as Gullodus sicilianus as suggested by Kozur (1993).477

However, Pseudohindeodus catalanoi Gullo and Kozur (1992) and Gullodus478

hemicircularis Kozur, 1993 should belong to Hindeodus, rather than479

PseudohindeodusorGullodus.480

Occurrence:KunguriantoCapitanian481

482

Gullodustieqiaoensisn.sp.SunandLai483

Plate4,figs.6,7.484

Noreportedspecimensaresimilartothisspecies.485

Etymology:Fromthenameofthesectionfromwherethespeciesisdescribed.486

Holotype:SpecimenS1_060 (Pl.4,fig.6)fromsample41-1ofBed41,ChihsiaFm.,487

TieqiaoSection,SouthChina.488

Paratype:SpecimenS1_062 (Pl.4,fig.7)fromsample41-2ofBed41,ChihsiaFm.,489

TieqiaoSection,SouthChina.490

Diagnosis:AGullodusspecieswithahighlength/heightratioandarobustcusp.491

25

Description:Bodyslimandelongated.Length/heightratiois~2.Thecuspistall,492

wideandrobust,normallytwiceashighasthedenticlesandthreetimeswider493

thanthedenticles.13-17denselyarrayeddenticlesdeceaseinheightposteriorly.494

Posteriordenticleson thebasalcavityaremoreexpandedandthuswider than495

therest.Theycanbelowerandmorefused.Thebasalcavityisexpanded,leafor496

irregularshapedandoccupiestheposterior2/3oftheelement.Thewidestpoint497

isintheposterior1/4to1/3.498

Remarks: This species has a very high length/height ratio and a posteriorly499

positioned, expanded but non-ornamented basal cavity that extends to the500

posterior end. It thus belongs to Gullodus rather than Hindeodus or501

Pseudohindeodus.502

Occurrence:lowerChihsiaFm.(earlyKungurian),Tieqiao,SouthChina503

504

GenusHindeodusRexroad&Furnish,1964505

HindeoduscatalanoiGulloandKozur,1992506

Plate7,Figs.6-8.507

PseudohindeoduscatalanoiGulloandKozur,1992p.225,pl.5,fig.A.508

HindeodusgulloidesBurrettetal.2015,p.111-113,Fig.6,figs.J-I.509

Diagnosis: A Hindeodus species that is triangular shaped with 2 to 3 anterior510

coalesceddenticlesand12-15denselyarrayeddenticles.511

26

Remarks: The species resembles its Artinskian-Kungurian and “Roadian”512

predecessors H. hemicircularis Kozur 1993 and H. gulloides Kozur andMostler,513

1995.Theyallhavetwotothreeanteriordenticles.However,H.hemicircularisis514

sub-semicircularshapedandhasfewerbutwiderdenticleswhileH.gulloides is515

moreelongatedandhasamuchbroadercuspthanthecurrentspecies. 516

Occurrence: upper Maokou Fm. (middle-late Capitanian), Tieqiao, South China;517

WordianofSicily.518

Hindeodussp.ASunandLai519

Plate4,Figs.23,26.520

Diagnosis: A Hindeodus species whose outline is close to that of an isosceles521

triangle.522

Description:Bodytriangularshapedwitha longanterioredge.Anteriorangle is523

around 45炣-60炣. Two or three small coalesced denticles may develop on the524

anterior edge. Medium sized cusp followed by three low denticles. Posterior525

denticlesaretallerandwideranddecreaseinheighttowardstheposteriorend.526

Thebasalcavityismediallyexpandedandcentralpositioned.527

Remarks:ThespeciesresemblesH.permicusbutdiffersbyitsoutlineandshapes528

ofdenticles.529

Occurrence:upperKungurian,basalMaokouFm.ofSouthChina530

GenusPseudohindeodusGulloandKozur,1992531

27

Pseudohindeodusellipticaen.sp.SunandLai532

Plate4,fig.13;Plate7.fig.14.533

Pseudohindeodussp.Wang,1995,pl.1,figs.1a,1b.534

Etymology:Fromtheovalshapeofthebasalcavityofthespecies.535

Holotype:SpecimenS7_001 (Pl.7,fig.14)fromsample104-2ofBed104,Maokou536

Fm.,TieqiaoSection,SouthChina.537

Paratype:SpecimenS2_075 (Pl.4,fig.13)fromsample104-2ofBed104,Maokou538

Fm.,TieqiaoSection,SouthChina.539

Diagnosis:AGullodusspecieswithanasymmetricalbasalcavitythatisnearoval540

inshape.541

Description:Elementissmallandrounded.Cuspis large,robustandhigherand542

broaderthananyfollowingdenticles.The5-8denticles immediatelybehindthe543

cusparethinandmorefusedwitheachotherandthuscanappearasaridge.The544

last 4-6 denticles are the largest amongst all denticles. They are lower, more545

roundedinshapeandrelativelyevenlyspacedwitheachotherwithasmallgap546

inbetween.Thebasalcavityisdecoratedwithanapron,horizontallyexpanded,547

asymmetricalandveryrounded.Theoutlineofthebasalcavityisclosetoanoval.548

Remarks:thespeciesresemblesPseudohindeodusramovsi.However,ramovsihas549

aneartriangularbasalcavitywhilstPseudohindeodusellipticaen.sp.hasamore550

roundedbasalcavity.551

28

Occurrence:upperKunguriantolowermostRoadian,basalKufengFm.andlower552

MaokouFm.ofSouthChina.553

554

GenusSweetognathusClark,1972555

Sweetognathusasymmetrican.sp.SunandLai556

Plate1,Figs.1,7,14,17.557

Etymology:Thespeciesnamereferstoitsasymmetricanteriortransverseridges.558

Holotype:SpecimenS1_018(Pl.1,Fig.1)fromsample18-1ofBed18,ChihsiaFm.,559

TieqiaoSection,SouthChina.560

Paratypes:Specimen S1_037 (Pl. 1, Fig.7) from sample 22-2 of Bed22, Chihsia561

Fm.,TieqiaoSection,SouthChina.562

Diagnosis:AType III sweetognathid (definition followsRitter,1986)withshort563

bladeandasymmetricanteriortransverseridges.564

Description:Shortblade,oftenbearing4-6denticles;thecuspismoderatelybig,565

the firstdenticle is thebiggestandveryoften fusedwith thecuspand formsa566

high robust cusp; the other denticles are much smaller, lower and more fused567

toward to the carina. The first two denticles are occasionally both very high,568

robustand triangular inshape.Transverseridgesareclearly incised.Thereare569

commonly 6 to 8 transverse ridges. The first one or two ridges are always570

asymmetricallydeveloped—inmostcasestheleftnodesaremissing.Thewidest571

partof thecarina is inthemiddle.Thebasalcavity is leaf- toheart-shapedand572

29

moderatelyexpanded,occupyingtheposteriorhalfofthefullelementlength. 573

Remarks:This species is similar to Sw. subsymmetricus.Both speciesdeveloped574

asymmetricanteriortransverseridges.However,thecurrentspeciesdiffersfrom575

Sw. subsymmetricus by: 1) the length ratio of free blade/carina < 1 (most576

commonly1/3),whereasthatofSw.subsymmetricusisgenerally≥1;2)thecuspis577

large tall and robust, whereas that of Sw. subsymmetricus is moderately large,578

comparedwithotherdenticlesontheblade;3)anapparentgapbetweenblade579

and carina; Sw. subsymmetricus has low small denticles connecting blade and580

carina;4)Sw. subsymmetricushasa lessexpandedbasal cavityandanarrower581

carina, therefore appears more “slim”; 5) gaps between transverse ridges that582

becomelagertowardtheposteriorend. 583

ThoughSw.subsymmetricusandSweetognathusasymmetrican.sp.mayhave584

close affinities,Sw.asymmetrica n. sp. is restricted to theArtinskian to earliest585

Kungurian whereas Sw. subsymmetricus is found in younger rocks of late586

Kungurian to Roadian age (Kozur, 1995). Many reported occurrences of Sw.587

subsymmetricus inpre-middle-Kungurianstrata (thathavenotbeen illustrated)588

shouldbereassessed.589

The paratype shares a few common featureswithSw. variabilis. They both590

havetwobigtriangular-shapeddenticles.Thekeydifferenceisthepositionofthe591

basalcavity.Sw.variabilishasabasalcavityneartheposteriorend.Inaddition,592

Sw.variabilishasalongblade(blade/carinaratio!1)andfivetransverseridges593

30

with the widest being near the posterior end. Sw. asymmetrica n. sp. has a594

blade/carinaratioalways<1,andusuallysevenormoretransverseridgeswhile595

the widest occurs near the middle of the body. In addition, neither of Sw.596

subsymmetricus and Sw. variabilis should be considered as synonyms of Sw.597

paraguizhouensisandSw.guizhouensis(Shenetal.,2012).598

Occurrence:Artinskian-basalKungurian,basalChihsiaFm.ofSouthChina599

Note:Thespecimenshowninfig.3inPl.4seemlyhasagapbetweenbladeand600

carina.ThisisonlybecauseinthelateralviewtheSEMtookthepartwithmissing601

nodesintheasymmetricanteriortransverseridges.602

Sweetognathussp.A603

Pl.1fig.9604

Diagnosis: A Type III sweetognathid with tall and slim denticles and narrow605

ridges.606

Description:Bodyelongatedwithaheight/lengthratio≈ 1/2.Cusptallandslim,607

at least twice as high as any following denticles. The cusp is immediately608

followedby five to six very slimdenticles.The first and thirddenticles are the609

lowest. A gap is developed between the fourth and fifth denticles. Nodes are610

short,forming5-7lowandgenerallyevenlyspacedridges.611

Sweetognathustoriyamai(Igo,1981)612

Pl.1,fig.12,15.613

31

NeostreptognathodustoriyamaiIgo,1981,p.42-43,pl.6,figs.1-16614

SweetognathuswhiteiIgo,1981,Pl.7,fig.7?615

Remarks: The denticles of this species point forwards. The carina is616

lens-shaped—thus the widest is near the middle. There is a short and narrow617

ridgeconnectingthebladeandcarina.Theridgeisrelativelyhighanteriorlyand618

decreasesinheighttowardsthecarina,thusgivingatriangularshapeiflaterally619

viewed. 620

Comparisons:Theshortnarrowridgebetweenthefreebladeandcarinaisoneof621

the most distinguishable features of this species. This species has a broad,622

lens-likecarina,whichissimilartoSw.behnkeni.However,thelatterspecieshas623

“ledge-like” decorations on the carina, whereas Sw. toriyamai is decorated by624

lowertransverseridges.625

Occurrence: Artinskian, basal Chihsia Fm. of South China andKuchibora Fm. of626

Japan.627

628

7.Conclusions:629

Adetailed conodontbiostratigraphic and taxonomic studyof theEarly and630

Middle Permian strata at Tieqiao, South China has enabled recognition of 21631

mainand7subordinateconodontzones.Threenewspeciesareestablished.The632

followingconclusionscanbedrawn:633

32

1) The Tieqiao strata record a change in conodont faunas from Early Permian634

Sweetognathus dominated assemblages to Middle Permian gondolellids635

dominatedassemblagesfromthelatestKungurianonwards.Thisshiftcoincided636

witharelativesea-levelriseandchangetodeeperwaterfacies.637

2) The Early Permian Sweetognathus fauna represents an important evolution638

lineageandashallower(surface?)watergroup,whichevolvedinparalleltothe639

contemporarybutpossiblydeeper-dwellingMesogondolellafauna.640

3) The Chihsia Fm., which had been in many cases erroneously regarded as a641

MiddlePermianunit, isofEarlyPermianage.ItspanstheArtinskiantothelate642

Kungurian whilst the overlying Maokou Fm. straddles the Early and Middle643

Permian from the late Kungurian to latest Capitanian. The Chihsia/Maokou644

lithological boundary is thus locally not suitable for defining the Early-Middle645

Permianboundary(Kungurian-Roadianstageboundary).646

4)SpeciessuchasJ.palmataandJ.errataoccurattime-equivalentstratigraphic647

levels at Tieqiao as in west Texas, suggesting that they can be used for648

intercontinentalcorrelations.649

650

Acknowledgements651

Manycolleagueshelpedwithfieldandlabwork,includingH.S.Jiang(Wuhan),652

F. Li (now Guilin), Q. Li (now Qingdao), D. Lutz (Erlangen), F. Nenning (now653

Münster), W. Pan (now Guangzhou), L.N. Wang (Wuhan), Y.J. Yan (now654

33

Lianyungang)andW.Q.Xue(Wuhan).H. IgoandB.R.Wardlaware thanked for655

providing conodont literature. Y.D. Sun acknowledges the Alexander von656

Humboldt Foundation for a fellowship. This study is supported by the Chinese657

Fundamental Research Funds for the Central Universities (CUG130615), 973658

Program(2011CB808800),theNaturalScienceFoundationofChina(41272044;659

41472087;41572002)andthe111Project(B08030).DBacknowledgesfunding660

fromtheUKNaturalEnvironmentResearchCouncil(grantNE/J01799X/1).661

662

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KungurianStage,EarlyPermian(Cisuralian)Series.ActaGeologicaSinica,836

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Norte Mountains. In: Wardlaw, B.R., Grant, R.E., Rohr, D.M. (Eds.), The844

Guadalupiansymposium-SmithsonianContributionstotheEarthSciences,845

pp.37-87.846

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ApacheMountains,WestTexas.Micropaleontology,56(1-2):149-183.848

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M.,Ali,J.R.,Lai,X.,Jiang,H.,Cope,H.,Bottrell,S.H.,2009a.Volcanism,Mass850

Extinction, and Carbon Isotope Fluctuations in the Middle Permian of851

China.Science,324:1179-1182.852

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2009b.Faciesanalysisandsea-levelchangeattheGuadalupian–Lopingian854

Global Stratotype (Laibin, South China), and its bearing on the855

end-Guadalupian mass extinction. Journal of the Geological Society,856

166(4):655-666.857

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southeasternIdaho.JournalofPaleontology,25(3):356-364.859

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40

CorrelationofPermian-TriassicBoundaryinMeishanSection,Changxing,861

Zhejiang Province. Earth Science-Journal of China University of862

Geosciences,20(6):669-676.863

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the Maokou Formation at the Tieqiao section, Guangxi, South China.865

Palaeoworld,24(3):263-276.866

867

Figurecaptions868

Fig. 1 Middle Permian palaeogeographic reconstructions of South China and869

Laibinarea(afterWangandJin,2000;Wignalletal.,2009b).870

871

Fig.2Fieldphotographsofthestudiedsection.A,anoverviewoftheChihsiaFm.872

inthelowerpartofthesection.Adiggerinthefarside(bluesquare)asscale.B,a873

close reviewof fine laminatedBed111-112 transition (Roadian-Wordian). The874

pen(~15cmlong)asscale.875

876

Fig. 3 Log of the lower part of Tieqiao section (Asselian to Kungurian) with877

conodontrangesandzonation.878

879

Fig. 4 Log of the middle part of Tieqiao section (Kungurian to Wordian) with880

conodont ranges and zonation. Keys are the same as in Fig. 3. Note that the881

reportedoccurrenceofMesogondolellabisselliinBed91(Shaetal.,1990)cannot882

41

beconfirmedbyourdataset(fordetailsseediscussionoftheSw.adjunctuszone).883

Keysisthesameasinfigure3.884

885

Fig.5LogoftheupperpartofTieqiaosection(WordiantoWuchiapingian)with886

conodontrangesandzonation.Keysisthesameasinfigure3.887

888

Fig. 6 Correlation chart of the Early-Middle Permian with standard conodont889

zonation(Hendersonetal.2012)andTieqiao(thisstudy)andNashui(Meietal.,890

2002) sections. 1.,Pseudosw.monocornus; 2.,H. gulloides; 3.,G. sicilianus; 4.,H.891

excavates.892

893

Plate1.SEMimagesofTieqiaoconodonts-genusSweetognathus.Barscalefor100894

μm, ‘a’ for oral view, ‘b’ for lateral view. Default is oral view. 1, 7, 14, 17.895

Sweetognathus asymmetrica n. sp., 1, holotype, S1_018 (18-1); 7, paratype,896

S1_037 (22-2); 14, S_001 (18-1); 17, S_006 (24A); 2, 16. Sweetognathus whitei897

(Rhodes, 1963), 2, S1_019 (18-1); 16, S_005 (23A); 3, 8. Pseudosweetognathus898

costatus Wang, Ritter and Clark, 1987, 3, S1_021 (19-2), 8, S1_025 (21-2). 4.899

Sweetognathussp.4,S1_023(19-2);5.TransitionalformfromSw.inornatustoSw.900

asymmetrica n. sp., S1_038 (22-2); 6. Sweetognathus sp., S1_031 (22-1). 9.901

Sweetognathus sp. A., S1_026 (21-2); 10. Sweetognathus inornatus Ritter, 1986,902

S1_030(22-1);11.Sweetognathuscf.bogoslovskajaeKozurinKozurandMostler,903

42

1976, S1_020 (18-1); 12, 15. Sweetognathus toriyamai (Igo, 1981), 12, S_002904

(17c),15,juvenileform,S_003(17c);13.Neostreptognathodusexgr.pequopensis,905

S_004(17c).906

907

Plate 2. SEM images of Tieqiao conodonts—genera Sweetognathus,908

Pseudosweetognathus,NeostreptognathodusandHindeodus.Scalebaris100μm,909

‘a’fororalview,‘b’forlateralview.Defaultisoralview.1,2,4,9.Sweetognathus910

bogoslovskajae Kozur in Kozur and Mostler, 1976, 1, S1_039 (22-2), 2, S1_043911

(24-3), 4, juvenile, S1_057 (39-1), 9, S1_051 (27-1); 3, 12. Sweetognathus912

guizhouensis Bando et al., 1980, 3. S1_048 (26-3), 12. S1_055 (39-1); 5-7.913

PseudosweetognathuscostatusWang,RitterandClark,1987,5,S1_047(26-2),6.914

S1_049 (26-4), 7. S1_045 (25-2); 8. Neostreptognathodus prayi Behnken, 1975,915

gerontic form, S1_046 (25-2); 10. Sweetognathus clarki Morphotype I, (Kozur,916

1976),S1_050(27-1);11.Sweetognathus inornatusRitter,1986,S1_053(29-1);917

13. Hindeodus aff. catalanoi, S1_022 (19-2); 14, 16, 17. Hindeodus minutus918

(Ellison, 1941), 14, S1_044 (25-1), 16, S1_056 (39-1), 17, S1_052 (28-1); 15.919

Hindeodussp.S1_042(23-3).920

921

Plate 3. SEM images of Tieqiao conodonts—genera Sweetognathus and922

Pseudosweetognathus. Scalebar is 100μm, ‘a’ for oral view, ‘b’ for lateral view.923

Default is oral view. 1-3.Pseudosweetognathus costatusWang,Ritter andClark,924

43

1987,1.S1_065(52-2);2.S1_066(58-1),3.S1_068(65-2);4,5.Sweetognathus925

iranicusKozur,1975,4,S1_069(66-3),5,S1_071(71-1);6.Pseudosweetognathus926

monocornus(DaiandZhang,1989),S2_001(94-2);7,9,19.Sweetognathussp.7.927

S1_072 (90-7), 9. S2_002 (97-2), 19. S2_020 (100-1); 8, 10, 11. Sweetognathus928

adjunctus (Behnken, 1975), 8. S2_004 (97-2), 10. S2_005 (97-2), 11. S1_076929

(91-1); 12, Sweetognathus cf. paraguizhouensis S1_078 (91-3); 13. Transitional930

formbetweenSweetognathusiranicusandSweetognathushanzhongensis,S2_007931

(99-4); 14.Sweetognathus subsymmetricsWang,Ritter andClark, 1987, S2_039932

(100-3);15-18.Sweetognathushanzhongensis(Wang,1978),15,S2_038(100-5),933

16,S2_018(100-1),17,S2_010(100-1),18,S2_028(100-3).934

935

Plate 4. SEM images of Tieqiao conodonts—genera Sweetognathus, Gullodus,936

Hindeodus and Pseudohindeodus. Scale bar is 100 μm, ‘a’ for oral view, ‘b’ for937

lateral view. Default is oral view. 1. Sweetognathus sp. S2_049 (102-2); 2-4.938

SweetognathussubsymmetricsWang,RitterandClark,1987,2.S2_051(102-3);3.939

S2_056(102-4);4.S2_058(102-4);5,15.SweetognathusiranicusKozur,1975,5,940

S2_082(105-3),15,S2_072(103-2);6-7.Gullodustieqiaoensisnsp.,6.holotype,941

S1_060 (41-1), 7. paratype, S1_062 (41-2); 8. Gullodus sicilianus (Bender and942

Stoppel, 1956), S3_020 (115-4); 9, 10, 16, 18. Transitional forms between943

HindeodusandPseudohindeodus.Notethattheseelementsdevelopedweakapron944

structures on basal cavities. 9. S1_074 (91-1), 10. S1_075 (91-1), 16. S2_057945

(102-4),18.S2_053(102-3);11,12.GullodusduaniMeietal.,2002,11.S1_013946

44

(TQ-28), 12. S3_022 (115-7); 13. Pseudohindeodus ellipticae n. sp. Sun and Lai,947

paratype, S2_075 (104-2); 14.Pseudohindeodus ramovsi Gullo andKozur, 1992,948

S2_073(103-4);17.Hindeoduscf.wordensisWardlaw,2000;17,S2_060(102-5);949

19, 20. Hindeodus cf. julfensis 19, S2_014 (100-1), 20. S2_011 (100-1); 21.950

Hindeoduscf.permicus,S2_050(102-2);22,36.Hindeodussp.22,S2_061(102-5),951

36, S2_022 (100-3); 23, 26. Hindeodus sp. A. 23, S2_068 (103-2); 26, S2_084952

(106-1). 24, 25, 27, 30-32, 34, 35. Hindeodus permicus (Igo, 1981) 24. S2_081953

(105-3),25.S2_034(100-4),27.S2_026(100-3),30.S2_083(105-3),31.S2_016954

(100-1), 32. S2_062 (103-1), 34. S2_071 (103-2); 35, S2_067 (103-2). 28, 29.955

Hindeodusminutus (Ellison,1941),28.S2_027(100-3);29.S2_021(100-2);33.956

HindeodusgolloidesKozurandMostler,1995,S2_066(103-2).957

958

Plate 5. SEM images of Tieqiao conodonts—genera Mesogondolella and959

Jinogondolella.Scalebaris100μm,‘a’fororalview,‘b’forlateralview.Defaultis960

oralview.1,7.transitionaltypebetweenM.lambertitoJ.nankingensis,1,S3_001961

(109-2),7,S3_012(113-2);2.MesogondolellalambertiMeiandHenderson,2002,962

S3_002(109-2);3,8.Mesogondolellasp.,3,S3_004(109-3),8.S3_013(113-7);4.963

Mesogondolellaidahoensis(Youngquist,Hawley,Miller,1951),S3_005(110-2);5,964

6.Mesogondolellasiciliensis(Kozur,1975),5.S3_007(111-1);6.S3_006(111-1);965

9.Jinogondolellanankingensis(Ching,1960),S3_011(111-5);10-11.Jinogodolella966

errataWardlawandNestell, 2000,10. S3_019 (115-3),11. S3_017 (115-2);12.967

Jinogondolella aserrata (Clark and Behnken, 1979), S3_021 (115-4); 13, 16.968

45

Jinogondolellasp.,13.SP_051(115-3),16,S3_037(116-7);14,15.Jinogondolella969

postserrata (Behnken, 1975), S3_028 (116-1); 15. S3_036 (116-7); 17, 18.970

Jinogondolellashannoni(Wardlaw,1994),17.S3_040(116-8);18,S3_030(116-2);971

19.Jinogondolellaaltudaensis(Kozur,1992),S3_033(116-3).972

973

Plate6. SEM imagesofTieqiao conodonts—genera JinogondolellaandClarkina.974

Scale bar is 100 μm, ‘a’ for oral view, ‘b’ for lateral view and ‘c’ for back view.975

Defaultisoralview.1.Jinogondolellaprexuanhanensis(MeiandWardlaw,1994),976

S4_004 (TQ-11); 2. Jinogondolella cf. prexuanhanensis SP_010 (118-2); 3-5.977

Jinogondolellashannoni(Wardlaw,1994),3.S3_062(118-2);4.S4_006(TQ-17+);978

5,SP_014(118-2);6,17.Jinogondolellasp.,6,SP_013(118-2),17,S_035(119A);979

7. Jinogondolella xuanhanensis (Mei and Wardlaw, 1994), 06-70_023 (TQ-6f);980

8-11. Jinogondolella granti (Mei and Wardlaw, 1994), 8. 06-70_024 (TQ-6f), 9.981

06-70_022 (TQ-6f), 10. TQ6f_010 (TQ-6f), 11. 06-70_027b (TQ-6f); 12-13.982

Clarkina postbitteri Mei and Warldlaw, 1994, 12. S6_054 (TQ-1), 13. C6_040a983

(TQ-1). 14. Clarkina sp., S6_055 (TQ-1); 15. Clarkina transcaucasica Gullo and984

Kozur, 1992, S4_003 (134-9); 16. Clarkina hongshuiensis Henderson, Mei and985

Wardlaw,2002,S_029(TQ-1).986

987

Plate 7. SEM images of Tieqiao conodonts—genera Hindeodus, Jinogondolella,988

Mesogondolellaand Sweetognathus.Scalebar is100μm, ‘a’ fororalview, ‘b’ for989

46

lateral view. Default is oral view. 1, transitional form between Sweetognathus990

bogoslovskajae and Sweetognathus inornatus, S_007 (24A); 2. Sweetognathus991

inornatus Ritter, 1986, S_008 (26C); 3. Sweetognathus fengshanensis Mei and992

Wardlaw,1998,S_016(117-3);4.Mesogondolellaidahoensis(Youngquist,Hawley993

andMiller,1951),S_009(109-2);5.Jinogondolellapalmata(NestellandWardlaw,994

2010), S_025 (111-1-2); 6-8. Hindeodus catalanoi (Gullo and Kozur, 1992), 6,995

S3_052 (117-2), 7, S3_052 (117-2), 8, S3_043 (116-12); 9-10. Sweetognathus996

hanzhongensis (Wang, 1978), 9, S4_012 (TQ-25), 10, S_025 (115-8). 11-12.997

Pseudohindeodusaugustus (Igo,1981),11, S7_007 (102-4),12, S7_005 (102-4).998

13.Pseudohindeodussp.S7_003(104-2).14.Pseudohindeodusellipticaen.sp.Sun999

andLai,holotype,S7_001(104-2).1000