内蒙古上白垩统二连组一长颈的镰刀龙类1)

内蒙古上白垩统二连组一长颈的镰刀龙类

张晓红1　徐　星2　赵喜进2　保罗 塞雷诺3

匡学文4　谭　林1

(1内蒙古国土资源厅龙浩地质古生物研究中心　呼和浩特　010010)

(2中国科学院古脊椎动物与古人类研究所北京)

(3芝加哥大学生物与解剖学系　芝加哥)

(4天津自然博物馆　天津　)1)

),化石记录主要局限于亚洲白摘要　镰刀龙类(又称。,这类恐龙的系统位置存在(RussellandDong,1994;Xuetal.,1999)表明这类恐龙属于虚骨龙类,(Sues,1997;MakovickyandSues,1998;Xuetal.,1999;Sereno,1999)。

新发现于内蒙古苏尼特左旗赛罕高毕上白垩统二连组的镰刀龙类化石材料代表这类恐

龙的一个新属种。杨氏内蒙古龙(Neimongosaurusyangigen.etsp.nov.)的正型标本为一较为完整的骨架,是已知镰刀龙类当中第一件在同一个体中保存了大多数脊椎和几乎所有肢骨的标本。

依据以下特征将内蒙古龙归入镰刀龙超科:U形的下颌联合部、齿骨前端向下弯曲、齿骨

前部没有牙齿、牙齿有一个收缩的基部、近圆形的齿根和叶形的齿冠、前部颈椎的神经脊低矮而轴向较长、后部颈椎背视呈X形、肱骨近端角状、肱骨有后转子、肱骨的尺骨髁和挠骨髁位于前部并为一狭窄槽分开、肠骨的耻骨柄细长而坐骨柄短以及跖部短。

内蒙古龙的以下特征区别于其他镰刀龙类:前部尾椎的横突下部有一圆形的窝,桡骨二

头肌结节非常发育,后足趾节近端跟部非常发育,胫骨的腓骨嵴长,明显超过胫骨长度的一半,肠骨髋臼前支外侧面转向背方,尾椎前关节突向两侧侧伸明显。

镰刀龙类有一些未见于其他手盗龙类的特征,表明这类恐龙较为原始,可能和似鸟龙类

关系较近(Sereno,1999),但其他一些证据表明镰刀龙类较为进步,可能和窃蛋龙类关系较近(MakovickyandSues,1998;Xuetal.,1999)。内蒙古龙高度气孔化的脊椎和进步的肩带形态

表明镰刀龙类相当进步。其中加长的颈部和缩短的尾部等特征非常类似于窃蛋龙类。这些特征的发现支持了镰刀龙类和窃蛋龙类的系统关系较近的假说。

关键词　内蒙古苏尼特左旗,上白垩统,镰刀龙类

中图法分类号　Q915.864

1)国土资源部九五计划前沿科技项目(编号:9501130)和国家自然科学基金委员会人才培养基金项目(编号:J9930095)资助。

收稿日期:2001-04-26

ALONG2NECKEDTHERIZINOSAUROIDDINOSAURFROMTHE

UPPERCRETACEOUSIRENDABASUFORMATIONOF

NEIMONGOL,PEOPLE’SREPUBLICOFCHINA

ZHANGXiao2Hong1　XUXing2　ZHAOXi2Jin2　PaulSERENO3

KUANGXue2Wen4　TANLin1

(1

(2

(3

(4LongHaoGeologicPaleontologicalResearchCenter,NeiMongol　　)InstituteofVertebratePaleontologyandPaleoanthropology,nese100044)DepartmentofOrganismalBiologyandAnatomy,U　　USA)TianjinMuseumofNaturalHistory　Tianjin　Abstract　TwopartialUpperCretaceousIrenDabasuFormation

ofNeiMongoltheropod.Neimongosaurusyangigen.etsp.

nov.,ispreservemostoftheaxialcolumnandnearlyallofthelong

Distinctivecharacteristicsofthenewspeciesincludeanteriorcaudal

afossaunderthetransverseprocess,radiuswithaprominentbicepstubero2

sity,pedalphalangeswithwelldevelopedheels,tibiawithanextremelylongfibularcrest

thatismuchlongerthanthehalflengthofthetibia,lateralsurfaceofpreacetabularprocesstwisted

tofacedorsally,andcaudalvertebraewithwidelypergentprezygapophyses.Neimongosaurus

displaysafewcharactersthatarenotreportedinothertherizinosauroidsbutdooccurinsome

advancedmaniraptorians,suchashighlypneumatizedvertebraandderivedshouldergirdle.

Particularlytheelongatedneckandshortenedtailprovidefurtherevidenceforacloserelationship

betweentherizinosauroidsandoviraptorsaurs.

Keywords　Sunitezuoqi,NeiMongol,UpperCretaceous,therizinosauroid

1　Introduction

TherizinosauroidscompriseanunusualherbivorousgroupoftheropoddinosaursthathavebeenrecoveredalmostexclusivelyindepositsofCretaceousageinAsia.ThefirstremainswerefoundinMongoliaandconsistedoftheenormousmanualclawsofoneofthemostspecializedmembersofthegroup,Therizinosauruscheloniformis(Maleev,1954).TherizinosauroidsarenowrepresentedbypartialskeletonsofbasaltaxafromtheEarlyCretaceous,suchasBeipiaosaurusinexpectus(Xuetal.,1999)andAlxasauruselesitaiensis(RussellandDong,1994),andgenerallylesscompleteskeletalremainsfrommorederivedtaxaofLateCretaceousage,includingNanshiungosaurusbrevispinus(Dong,1979),Segnosaurusgalbinensis(Perle,1979),andErlikosaurusandrewsi(Perle,1980;Clarketal.,1994).AbasaltaxonisalsoknownfromtheEarlyJurassicSouthChina(ZhaoandXu,1998;Xuetal.,2001).

Thegroupremainspoorlyknown,asthereisnotyetasinglespeciesthatpreservedtheskullinassociationwithareasonablycompleteskeleton,askeletonthatpreservesallofthelongbonesofforeandhindlimbs,oraskeletonthatpreservesalloftheaxialcolumn.

Wedescribehereskeletalmaterialsofanewtherizinosauroidthataddimportantnewinformationregardingtheanatomyofthesespecializedtheropods.Thefossilwasdiscoveredin1999atSanhangobiinNeiMongol(InnerMongolian)AutonomousRegionbyateamfromtheDepartmentofLandandResources,Hohhot.ThefossilremainswerecollectedinfluvialsandstonesoftheUpperCretaceousIrenDabasuFormation,whichhasyieldedapersedinosaurianfauna,includingthehadrosauidsBactrosaurusandGilmoreosaurusandthetheropodsArchaeornithomimus,Avimimus,andAlectrosaurus.ThisformationisnowregardedLateCretaceous(Senonian)inage(CurrieandEberth,1993).

Institutionalabbreviations:LH,LongHaoGeologicPaleontologicalResearchCenter,

284古　脊　椎　动　物　学　报　　　　　　　　　　　　　39卷DepartmentofLandandResources,Hohhot.

2　Systematics

TheropodaMarsh,1881

CoelurosauriaHuene,1914

Therizinosauroidea(Maleev,1954)

ThesuperfamilyTherizinosauroideahadgainedcurrencyasthepreferredhighertaxontoencompassallspeciesformerlyreferredtoas“segnosaurs”or“therizinosauridsRussellandDong,1994).WesuggestherethatcurrentwidespreadshouldbelinkedtoaphylogeneticdefinitionthatitswithinCoelurosauriayetclearlyunitesalltaxathataremorenosaurusthantoanyothercoelurosauriansubgroup.as:AllcoelurosaursclosertoTherizinosaurusthantoO,Oviraptor,VelociraptororNeornithes.hand,ismoreusefullyrestrictedtoderivedmembersoftheasbySereno(1998:65)toencompasstheentiregroup.redefinedhereas:Segnosaurus,Erlikosaurus,Nanshi,nosaurus,theircommonancestorandalldescendants.

Neimongosaurusyangigen.etsp.nov.

(pls.I～III)

Etymology　Neimongo,forNeiMongol,thegenerallocationofthesiteofdisc …… 此处隐藏：24806字，全部文档内容请下载后查看。喜欢就下载吧 ……