刺尾虫科三叶虫的起源和早期演化

收稿日期:19982012033国家自然科学基金项目(49262011)成果之一刺尾虫科三叶虫的起源和早期演化3袁金良(中国科学院南京地质古生物研究所　南京210008)尹恭正(贵州省地质矿产局区调院　贵阳550005) 提要　根据贵州东部晚寒武世早期地层内获得的刺尾虫科(Ceratopygidae )三叶虫新材料,论述了具有尾侧刺和不具尾侧刺的此类三叶虫共同起源于褶颊虫目的Mapaniidae ,以及它们的早期演化。

此外,还描述了此类三叶虫1新亚属、2新种和2新亚种及其个体发育过程中的一些变异。

对于正确认识寒武纪三叶虫的分类、演化具有一定的意义。

关键词　三叶虫Ceratopygidae 起源　早期演化1　前言Ceratopygidae 科三叶虫最初出现在中寒武世晚期,繁盛于晚寒武世中晚期,绝灭于早奥陶世,广泛分布于世界各地的台地边缘区和斜坡区。

对这一类三叶虫的研究虽然已有了100多年的历史,置于此科内的三叶虫也多达20余属,如Ceratopyge Hawle et Corda ,1847,Proceratopyge Wallerius ,1895,Proceratopyge (L opnorites )Troedsson ,1937,Proceratopyge (S i noproceratopyge )Lu et Lin ,1980,Diceratopyge Troedsson ,1937,Dichelepyge Harring 2ton et Leanza ,1952,Hysterolenus Moberg ,1898,Pseudohysterolenus Harrington et Leanza ,1957,O nychopyge Harrington ,1938,W annania Qiu ,1983,Charchaqia Troedsson ,1937,Y uepi ngia Lu ,1956,Pseudoyuepi ngia Chien ,1961(=Iw ayaspis K obayashi ,1962),A plotaspis Henderson ,1976,Tam daspis Lisogor ,1977(=Psiloyuepi ngia Qian et Qiu ,1983),Cerm ataspis Shergold ,1980,S ayram aspis Xiang et Zhang ,1985,Haniw oi des K obayashi ,1935,T ropi dopyge Harrington et Kay ,1951,M acropyge (Prom acropyge )Lu in Wang ,1964,M acropyge (M acropyge )Stubblefield in Stubblefield et Bulman ,1927,Hedi 2naspis Troedsson ,1951,Asiocephal us Palmer ,1968,Neohedi naspis Xiang et Zhang ,1984,Guoz ia Xiang et Zhang ,1985,Y uepi ngioi des Lu et Lin ,1984,?Metayuepi ngia Liu ,1977等(Harrington et al.,1959,p.0361;Fortey and Chatterton ,1988,p.196;卢衍豪等,1989,145页,154页;Peng ,1992,p.82,93,100,101),但在系统分类和演化等方面还有不同的观点,主要原因是对这类三叶虫还缺乏详细的个体发育和系统演化的研究。

从尾部的形态特征来看,此类三叶虫可分成二类:一类具有尾侧刺,另一类不具有尾侧刺。

Proceratopyge第38卷第2期1999年4月古　生　物　学　报ACTA PALAEON TOLO GICA SIN ICA Vol.38,No.2Apr.,1999Wallerius 是具有尾侧刺的Ceratopygidae 科三叶虫中最早出现的一个属,始见于中寒武世晚期,繁盛于晚寒武世早中期,绝灭于晚寒武世晚期,在北欧、亚洲、澳大利亚、美国阿拉斯加和南极洲等地都有分布,它不仅在洲际间地层对比上有一定的意义,而且在寒武纪古生物地理区系的划分上也有一定的价值。

研究它的起源和早期演化对于弄清整个这类三叶虫的系统分类、演化具有重要的意义。

A plotaspis (Cataplotaspis )subgen.nov.是不具尾侧刺的Cer 2atopygidae 科三叶虫中另一个重要的亚属,它几乎与Proceratopyge 属同时出现,繁盛于晚寒武世早期,绝灭于晚寒武世中期,且具有与Proceratopyge 形态十分相似的头盖和相同的胸节数(9节),研究它与Proceratopyge 属的演化关系,起源和早期演化同样具有十分重要的意义。

根据贵州东部万山镇南羊尾舟至寄马冲车夫组(晚寒武世早期)所产丰富的Ceratopygi 2dae 科三叶虫的新材料,本文将对Ceratopygidae 科三叶虫的起源和早期演化作初步的探讨。

2　Ceratopygidae 科三叶虫的起源有关科三叶虫的起源,一些学者曾作过研究。

Zhang 和Jell (1987,p.187-188)根据Proceratopyge 和M apania 两属头盖和尾部特征的比较,认为Proceratopyge 是由属于褶颊虫目的Mapaniidae 科的M apania 属演化而来。

Fortey 和Chatterton (1988,p.166-167,195-196,217)则通过节俭的系统演化分析法(PAU P )研究,确认Ceratopigidae 科三叶虫起源于栉虫目的Anomocaridae 科三叶虫。

笔者认为前一种观点较为正确,因为Proceratopyge 与M apania 具有许多共同点,如相同的头盖和头鞍形态,类似的头鞍沟模式,外边缘中部向后都具有矩形凸出。

而Proceratopyge 的尾侧刺则是通过M apania 的第一对大的尾肋脊向外延伸而形成的。

A plotaspis (Cataplotaspis )与M apania 则更为接近,前者幼虫的尾部后缘中部甚至具有向内凹陷,与后者成虫的尾部形态十分相似,只是在漫长的演化过程中,拉长了眼叶,扩宽了尾边缘和出现了头鞍中瘤才与M apania 相区别。

3　Ceratopygidae 科三叶虫的早期演化早期的Ceratopygidae 科三叶虫,除了独有的衍征(autapomorphies )外,如头鞍中瘤,短小的尾侧刺以及两侧与前边沟会合、中部向后弯曲与头鞍前背沟会合的拟复边缘线等,仍然保持许多近祖性状(plesiomorphies )特征,如截锥形的头鞍,三对侧头鞍沟,宽的头鞍前区,外边缘中部向后延伸出的脊状凸起,面线前支在眼叶之前平行向前延伸,横宽而短的尾部,分节少的尾中轴等。

自中寒武世晚期至晚寒武世早期(崮山期)已建和新建的属于Ceratopygidae 科三叶虫的种有Proceratopyge conif rons Wallerius ,P.nathorsti Westergaard ,P.si m ilis Westergaard ,P.m agnicauda Westergaard ,P.f uyangensis Lu et Lin in Peng ,P.z hejian 2gensis Lu et Lin ,Pseudoyuepi ngia laochatianensis Yang ,Ps.l.koutianw uensis Qiu ,Ps.aspi nosa Qiu ,A plotaspis (Cataplotaspis )quadrata subgen.et sp.nov.,A.(C.)spiculata subgen.et sp.nov., A.(C.)laochatianensis nobilis subsp.nov.,Proceratopyge conif rons si nensis subsp.nov.;其中Proceratopyge z hejiangensis ,Pseudoyuepi ngia laochatianensis961第2期袁金良等:刺尾虫科三叶虫的起源和早期演化koutianw uensis ,Pseudoyuepi ngia aspi nosa 与Pseudoyuepi ngia laochatianensis 为同一个种,并归入A plotaspis (Cataplotaspis )subgen.nov.亚属内(见系统描述部分)。

这一时期这类三叶虫总的演化趋势有以下特征:(1)头鞍由窄长变宽而短;(2)头鞍中瘤由后部逐渐向前移动,离颈沟距离增大;(3)两眼叶间固定颊由宽变窄,其眼叶则由短变长,位置由前向后移动;(4)面线前支则由微向内收缩变为近乎平行向前延伸至微向外扩散向前延伸;(5)尾部则由宽而短变为窄而长;(6)尾轴节数则由4节变为6节或7节;(7)外边缘中部后缘伸出的脊状凸起由三角形变为长方形至倒梯形。

在演化过程中,A plotaspis (Cataplotaspis )与Proceratopyge 唯一显著不同的是其眼叶由长变短,且较早地在头盖的内边缘上出现拟复边缘沟和拟复边缘线。

在这一演化系列中令人难以费解的是中寒武世晚期出现的Procer 2atopyge m agnicauda ,它已具备了晚寒武世中晚期繁盛的Proceratopyge (L opnorites )Troedsson 亚属的基本特征,如头鞍前区窄,拟复边缘线消失,固定颊在两眼叶之间窄,眼叶小位置靠前,后侧翼呈次三角形,尾部窄长,后缘向后强烈凸出,尾轴分节多(7节)等,从系统演化的角度来看,此种的时代值得怀疑。

综上所述,Ceratopygidae 科三叶虫的早期演化关系如插图1所示。

为了节省篇幅,有关属种描述仅用英文刊出,中文不再赘述。

本文所用三叶虫化石照片由胡尚卿摄制,笔者深致谢意。

插图1　中寒武世晚期至晚寒武世早期刺尾虫科三叶虫的演化关系Tentatively phylogeny of Ceratopygidae in late Middle Cambrian to early Late Cambrian071 古　生　物　学　报第38卷参考文献仇洪安,卢衍豪,朱兆玲等,1983.　三叶虫纲.华东地区古生物图册(一),早古生代分册.北京:地质出版社.28-254叶戈洛娃,项礼文,李善姬等,1963.　贵州及湖南西部寒武纪三叶虫动物群.中华人民共和国地质部地质科学研究院专刊,乙种,3(1):1-116朱兆玲,林焕令,张志恒,1979.　三叶虫类.西北地区古生物图册,青海分册(一).北京:地质出版社.81-116卢衍豪,1956a.　安徽滁县上寒武统L opnorites 动物群.古生物学报,4(3):267-283卢衍豪,1956b.　黔东玉屏上寒武统三叶虫.古生物学报,4(3):365-380卢衍豪,1964.　三叶虫类.王钰等编:华东区标准化石手册.北京:科学出版社卢衍豪,张文堂,朱兆玲等,1965.　中国的三叶虫(上下册).北京:科学出版社.1-766卢衍豪,周志强,周志毅,1986.　Onychopyge 动物群的新材料并论Onychopyge 的系统演化.中国科学院南京地质古生物研究所丛刊,第7号.南京:江苏科学技术出版社.69-126卢衍豪,林焕令,1989.　浙江西部寒武纪三叶虫动物群.中国古生物志,新乙种25号.北京:科学出版社刘义仁,1982.　三叶虫纲.湖南古生物图册.中华人民共和国地质矿产部地质专报二.地层古生物,第1号.北京:地质出版社.290-346林天瑞,1986.　.南京大学学报,22(1):129-146杨家　,1978.　湘西、黔东中上寒武统及三叶虫动物群.地层古生物论文集,第4辑.北京:地质出版社.1-82周天梅,刘义仁,孟宪松,孙振华,1977.　三叶虫纲.中南地区古生物图册(一).北京:地质出版社.104-266周志强,李晋僧,曲新国,1982.　三叶虫纲.西北地区古生物图册.陕甘宁分册(一).北京:地质出版社.215-294项礼文,张太荣,王景斌,成守德,白文贤,1985.　新疆北天山西段寒武纪地层及三叶虫动物群.中华人民共和国地质矿产部地质专报二.地层古生物,第4号.北京:地质出版社.1-243袁金良,尹恭正,1998.　贵州东部晚寒武世早期车夫组多节类三叶虫新属种.古生物学报,37(2):137-172钱义元,1961.　贵州三都和都匀寒武纪三叶虫.古生物学报,9(2):90-129彭善池,1987.　湖南桃源及慈利晚寒武世早期地层及三叶虫动物群.中国科学院南京地质古生物研究所研究生论文集,第1号.南京:南京大学出版社.53-134Fortey R A ,Chatterton B D E ,1988.　Classification of the trilobite suborder Asaphina.Palaeontology ,31(1):165-222Harrington H J ,et al.,1959.　Trilobita.In R C Moore (ed.):Treatise on Invertebrate Paleontology ,part O ,G eol.Soc.Amer.and Univ.Kansas ,Lawrence ,KansasHenderson R A ,1976.　Upper Cambrian (Idamean )trilobites from western Queensland ,Australia.Palaeontology ,19(2):325-364Hughes N C ,Rushton A W A ,1990.　Computer 2aided restoration of a Late Cambrian ceratopigid trilobite from Wales ,and itsphylogenetic significance.Palaeontology ,33(2):429-445Jago J B ,1987.　Idamean (Late Cambrian )trilobites from the Denison Range ,Southwest Tasmania ,Palaeontology ,30(2):207-231K obayashi T ,1935.　The Cambro 2Ordovician formations and faunas of South Chosen.Palaeontology part ⅢCambrian faunasof South Chosen with special study on the Cambrian trilobite genera and families.J.Fac.Sci.Imp.Univ.Tokyo (2),4(2):49-344K obayashi T ,Ichikawa T ,1955.　Discovery of Proceratopyge in the Chuangia zone in Manchuria ,with a note on the Cer 2atopygidae.Trans.proc.Palaeont.Soc.Japan n.s.,19:65-72Kraskov E N ,1977.　New representatives of Ceratopygidae and Olenidae from the Late Cambrian of southern Kazakhstan.InStukalina G A (ed.):New species of early plants and invertebrates from the SR ,4:56-60(in Russian )Lazarenko N P ,1966.　Biostratigraphy and some new trilobite from the Upper Cambrian of the Olenenk uplift and Kharaulakh171第2期袁金良等:刺尾虫科三叶虫的起源和早期演化271 古　生　物　学　报第38卷mountain.Uchen zap Palaeont.biostrati.Nauchno2Issled.Inst.G eol.Arkt,11:33-78(in Russian)Lisogor K A,1977.　Biostratigraphy of Upper Cambrian and Tremadoc trilobites of the Maly Karatau(southern Kazakhstan).In Zhuravleva I T and Rosova A V(eds.):Biostratigraphy and fauna of the Upper Cambrian and boundary strata.(New data from the Asiatic part of the U.S.S.R.Trudy Inst.G eol.G eoph.Akad.Nauk SSSR,Siber.otd.,313:197-265 Peng S C,1992.　Upper Cambrian biostratigraphy and trilobite faunas of the Cili2Taoyuan area,northwestern Hunan,China.Mem.Ass.Australasia Palaentologists,13:1-119Rushton A W A,1983.　Trilobites from the Upper Cambrian Olenus Z one in central England.In Briggs D E G,Lane P D (eds.):Trilobites and other early arthropods:papers in honour of Professor H.B.Whittington F.R.S.spec.pap.in Palaeont.,30:107-139Shergold J H,Cooper R A,Mackinnon D I,Y ochelson E L,1976.　Late Cambrian Brachiopoda,Mollusca and Trilobita from northern Victoria Land,Antarctica.Palaeontology,19(2):247-291Troedsson G T,1937.　On the Cambro2Ordovician faunas of western Quruq Tagh,eastern Tienshan.Palaeont.Sinica N.S.(B),2(whole ser.106):1-74Wallerius I D,1895.　Unders¨o kningar¨o fver med A gnost us laevigat us;Vesterg¨o tland,jamte en inledande¨o fversikt at Vesterg¨o tlands samtliga Paradoxideslager.G leerupska Universitets Bokhandeln.1-72Webby B D,Wang Qizheng,Mills L J,1988.　Upper Cambrian and basal Ordovician trilobites from western New South Wales.Palaeontology,31(4):915-938Westerg¨a rd A H,1922.　Sveriger Olenidskiffer.Sver.G eol.Unders¨o kn.,ser.c,18:1-205Westerg¨a rd A H,1947.　Supplementary notes on the Upper Cambrian trilobites of Sweden.Sver.G eol.Unders.Afn.ser.C, 41(8):3-34Westerg¨a rd A H,1948.　Non2Agnostidean trilobites of the Middle Cambrian of Sweden.Sver.G eol.Unders¨o kn ser,C,498: 3-32Whitehouse F W,1939.　The Cambrian faunas of northeastern Australia.part3Mem,Queensland,Mus.,11(3):179-282 Zhang W T,Jell P A,1987.　Cambrian trilobites of North China.Chinese Cambrian trilobites housed in the Smithsonian Insti2 tution.Beijing:Science press.1-459ORIGIN AN D EAR LY EV OL UTION OF CERAT OPY GIDAEL INNARSON,1869(TRI LOBITA)YUAN Jin2Liang(N anji ng Instit ute of Geology and Palaeontology,Chi nese Academy of Sciences,N anji ng210008)YIN G ong2Zheng(Geological S urvey,Guiz hou B ureau of Geology and Mi neral Ex ploration and Development,Guiyang550005)K ey w ords　Trilobita,Ceratopygidae,Origin,early evolutionSummaryStudy on new material of Ceratopygidae from lower Upper Cambrian(the Chefu Forma2 tion)of eastern Guizhou,South China indicates that Ceratopygidae with or without spinose py2 gidium may be a monophyletic group and may have a common origin with M apania(Mapani2idae of Ptychopariida ).Phylogeny of Ceratopygidae in late Middle Cambrian and early Late Cambrian is briefly discussed and shown in Text 2fig.1,One new subgenus ,2new species and 2new subspecies are established :A plotaspis (Cataplotaspis )quadrata subgen.et sp.nov.,A .(C.)spiculata subgen.et sp.nov.,A .(C.)laochatianensis nobilis subsp.nov.,Pro 2ceratopyge conif rons si nensis subsp.nov.Description of genera and speciesF amily Ceratopygidae Linnarson ,1869G enus Proceratopyge W allerius ,1895Type species Proceratopyge conif rons Wallerius ,1895R emarks Palmer (1968),Henderson (1976),Shergold et al.(1976,1982),Lisogor (in Zhuravleva et al.(1977),Lu and Lin (1980,1989),Rushton (1983),Jago (1987),Apollonov et al.(1984),Webby et al.(1988),and Peng (1992)discussed Proceratopyge and its possi 2ble subgeneric groupings and we follow Lu and Lin (1980,p.129;1989,p.145,259)in subdi 2viding Proceratopyge into three subgenera :Proceratopyge (P.)Wallerius ,1895,P.(L op 2norites )Troedsson ,1937and P.(S i noproceratopyge )Lu et Lin ,1980based on cranidial fea 2tures.P.(Proceratopyge )is characterized by the subconical glabella ,long frontal area ,well developed paradoublural line (or plectral line ),narrowly diverging anterior branches of facial su 2tures ,short to moderately long (exsag.)palpebral lobes placed centroposteriorly ,subtriangular posterolateral limbs and transverse poorly segmented pygidium.P.(L opnorites )is character 2ized by the subcylindrical to cylindrical glabella ,short frontal area ,the absence of paradoublural line ,narrowly diverging anterior branches of facial sutures ,short palpebral lobes placed anteri 2orly ,narrow fixed cheeks between palpebral lobes and long multisegmented pygidium.P.(S i noproceratopyge )bears the closest resemblance to P.(L opnorites ),however ,it can be dis 2tinguished mainly by its wider cranidial anterior margin ,more or less longer palpebral lobes placed more centroposteriorly ,narrower (exsag.)strape 2like posterolateral limbs and more strongly diverging anterior branches of facial sutures.Up to now more than 70species and sub 2species are assigned to Proceratopyge and their new placements are tentatively listed in Table 1.Table Ⅰ　List of species (subspecies )of Proceratopyge with its modern taxonomic placement Species or Subspecies nameNew placement 1.　P.ajguliensis Kraskov ,1977,pl.14,fig.1Prohedi nia 2.　P.angusta Whitehouse ,1939,pl.23,fig.21?3.　P.angustaxis Zhou ,in Zhou et al.,1982,pl.67,fig.21P.(Proceratopyge )4.　tica Ivshin ,1956,pl.8,figs.7-23P.(Si noproceratopyge )5.　P.(?)brevi rhachis Zhou ,in Zhou et al.,1977,pl.70,fig.7P.(Proceratopyge )6.　P.brevispi na Xiang et Zhang ,1985,pl.45,figs.10-15P.(L opnorites )7.　P.captiosa Lazarenko ,1966,pl.4,figs.7-10P.(L opnorites )?371第2期袁金良等:刺尾虫科三叶虫的起源和早期演化8.　P.(S.)changshanensis Lu et Lin,1989,pl.26,figs.6-8P.(Proceratopyge)9.　P.chuancigouensis Lin et Zhang,in Zhu et al.,1979,pl.43,figs.10-12P.(Proceratopyge)10.　P.chuhsiensis Lu,1956,pl.1,figs.1-6P.(Si noproceratopyge)?11.　 m unis J u,in Qiu et al.,1983,pl.72,fig.13P.(Si noproceratopyge)12.　P.conif rons Wallerius,1895;Westergaard,1948,pl.1,figs.7-16P.(Proceratopyge)13.　P.const ricta Lu,1964,pl.6,fig.1P.(Si noproceratopyge)14.　P.copiosa Xiang et Zhang,1985,pl.46,figs.1-4P.(L opnorites)15.　P.corrugis Pomanenko in Zhuravleva and Rozova,1977,pl.24,figs.18-21P.(Proceratopyge)16.　P.cryptica henderson,1976,pl.47,figs.19-24;pl.48,figs.1-3P.(Proceratopyge17.　P.cyli ndrica Chien,1961,pl.3,figs.8-10P.(L opnorites)18.　P.distensa Lu et Lin,1989,pl.24,figs.9-11P.(Proceratopyge)19.　P.(S.)disti ncta Lu et Lin,1989,pl.26,fig.5P.(Si noproceratopyge)20.　P.f enghw angensis Hsiang,in Jegorova et al.,1963,pl.10,figs.1-10P.(Proceratopyge)21.　P.f.ellipsoi des Liu,1982,pl.228,fig.6P.(Proceratopyge)22.　P.f uyangensis Lu et Lin,in Peng,1987,pl.13,figs.7-10P.(Proceratopyge)23.　P.(L.)f ragilis Troedsson,1937,pl.2,figs.3-6P.(L opnorites)24.　P.gordonensis Jago,1987,pl.26,figs.1-10;pl.27,figs.1-8P.(Si noproceratopyge)25.　P.(L.)grabaui Troedsson,1937,pl.2,figs.7-8;pl.3,figs.2-3P.(L opnorites)26.　P.gracilis Lermontova,1940,pl.49,fig.1P.(Proceratopyge)27.　P.i ncondita Harrington et Leanza,1957,figs.94-10?28.　P.i nex pectata Harrington,1938,pl.5,fig.17?29.　P.i nsueta Lin et Zhang,in Zhu et al.,1979,pl.44,figs.1-3P.(Si noproceratopyge)30.　P.kiangshanensis Lu,1964,pl.8,fig.3P.(Si noproceratopyge)31.　ta Whitehouse,1939,pl.25,figs.12,13P.(Proceratopyge)32.　tili mbata Zhou,in Zhou et al.,1977,pl.70,figs.11-13P.(Proceratopyge)33.　tili mbata Lee,in Y in et al.,1978,pl.179,fig.11P.(Si noproceratopyge) sanduensis Lu et Lin34.　ti rhachis Zhou,in Zhou et al.,1977,pl.70,figs.14-16P.(Si noproceratopyge)35.　P.liaot ungensis K obayashi et Ichikawa,1955,pl.2,figs.1-9P.(Si noproceratopyge)36.　P.longialata Zhou,in Zhou et al.,1982,pl.68,fig.2P.(L opnorites)37.　P.longif rons Lu et al.,1986,pl.10,figs.1-9P.(L opnorites)38.　P.longispi na Ivshin,1962,pl.19,figs.16,17Onychopyge?39.　P.margnicauda Westergaard,1947,pl.2,fig.11P.(L opnorites)40.　P.mi metica Xiang et Zhang,1985,pl.46,figs.11-14;pl.47,fig.1P.(L opnorites)41.　P.mi rabilis Lu et Lin,1989,pl.24,figs.6-8P.(Proceratopyge)42.　P.mitis Xiang et Zhang,1985,pl.45,figs.7-9P.(L opnorites)43.　P.nathorsti Westergaard,1922,pl.2,figs.3-5P.(Proceratopyge)471 古　生　物　学　报第38卷44.　P.nectans Whitehouse ,1939,pl.25,fig.8P.(Proceratopyge )45.　P.ocella Webby ,Wang et Mills ,1988,pl.85,figs.1-10P.(L opnorites )46.　P.(L.)orthogonialis Yang ,1978,pl.3,figs.1-4;pl.7,fig.21P.(Si noproceratopyge )47.　P.polita Whitehouse ,1939,pl.26,fig.14M apania 48.　P.portentosa Lazarenko ,1966,pl.4,figs.1-6Proceratopyge ?49.　P.(L.?)posterolateralis Peng ,1992,Fig.61j ,K P.(L opnorites )50.　P.propria Xiang et Zhang ,1985,pl.46,figs.6-10P.(Proceratopyge )51.　P.prot racta Peng ,1992,Fig.47H 2N P.(Proceratopyge )52.　P.(L.)rectispi nata Troedsson ,1937,pl.2,figs.1-2P.(L opnorites )53.　P.(L.?)robust us K obayashi ,1962,pl.6,fig.13P.(L opnorites ?)54.　P.(Kogeni um )rot unda K obayashi ,1935,pl.17,figs.6-9?55.　P.rot unda kraskov ,1960,pl.53,figs.20-22?56.　P.rutell um Whitehouse ,1939,pl.25,figs ,9-11,13A plotaspis 57.　P.schaganica Hajrullina ,1962,pl.4,figs.15-17Proceratopyge (?)58.　P.si milis Westergaard ,1947,pl.2,fig.1P.(Proceratopyge )59.　P.(S.)si nuata Lu et Lin ,1989,pl.26,fig.9P.(S.)disti ncta 60.　P.spectabilis Zhou ,in Zhou et al.,1982,pl.68,fig.4P.(Proceratopyge )61.　P.stabilis Zhou ,in Zhou et al.,1982,pl.68,fig.4P.(Proceratopyge )62.　P.taojiangensis Zhou ,in Zhou et al.,1977,pl.70,fig.17P.(L opnorites )63.　P.tenuita Lazarenko ,1966,pl.3,figs.10-16Proceratopyge (?)64.　P.tet rasolena J u ,in Qiu et al.,1983,pl.73,fig.7P.(Si noproceratopyge )65.　P.t riangula Ivshin ,1962,pl.19,fig.15Proceratopyge (?)66.　P.(Kogeni um )t riangularis K obayashi ,1935,pl.17,figs.4,5P.(L opnorites ?)67.　P.t runcata Yang ,in Zhou et al.,1977,pl.70,figs.18,19P.(Proceratopyge )68.　P.t ullbergi Westergaard ,1922,pl.2,figs.6,7P.(L opnorites ?)69.　P.w aergangensis Peng ,1992,Fig.47E ,FP.(Proceratopyge )70.　P.(S.)w uni ngensis Lin ,1986,pl.3,figs.6,7P.(Si noproceratopyge )71.　P.yardanshanensis Xiang et Zhang ,1985,pl.47,figs.2-10P.(Proceratopyge )72.　P.z hejiangensis Lu et Lin ,1989,pl.24,figs.1-3A.(C.)laochatianensis 73.　P.?z hitangensis J u ,in Qiu et al.,1983,pl.72,figs.14,15P.(Proceratopyge ) Occurrence Middle -Late Cambrian ,Eurasia ,North America ,Australia ,Antarctica.Proceratopyge (Proceratopyge )conif rons sinensis subsp.nov.(Pl.Ⅰ,figs.18,19)1989　Proceratopyge conif rons Lu and Lin ,p.147,pl.23,figs.9-11.Diagnosis Cranidium with relatively longer palpebral lobes and wider anterior border.Pygidium with 5axial rings and shorter marginal spines.571第2期袁金良等:刺尾虫科三叶虫的起源和早期演化671 古　生　物　学　报第38卷Description　G labella gently tapering forward,truncated anteriorly,occupying more than three fifths of cranidial length,with3pairs of shallow glabellar furrows,of which the S1is rep2 resented as curved depressions and isolated from axial furrows;the S2and S3are very faint, slightly slanting backward.An axial glabellar node apparent,distance from the node to occipi2 tal furrow nearly equal to the sagittal length of occipital ring.Occipital furrow deep,slightly bending backward,shallowing laterally;occipital ring prominent,slightly narrowing laterally. Frontal area wide(sag.),anterior border and preglabellar field subequal in length,rather flat, anterior border extending backward medially and forming a subtriangular plectrum.Anterior border furrow shallow,gently bending towards glabella medially.Fixed cheek moderately broad(tr.),gently vaulted.Eye ridges weak and short,nearly transverse.Palpebral lobes moderately long,semicircular,occupying about half of glabellar length,placed centroposteri2 orly.Palpebral furrows indistinct.Posterolateral limbs narrow,strape2like.Posterior border narrow,gently convex;posterior border furrow deep.Anterior branches of facial sutures long, subparallel forward with a gentle arc;posterior branches slanting outwards and backwards.Py2 gidium(used to be assigned to new species)short and broad.Axis with5axial rings and a very short postaxial ridge.Pleural area with2-3pairs of pleural ribs,of which the first pair ex2 tends into short marginal spines.Border moderately broad and flat.Border furrow shallow.Comparison　In the shape of glabella,the pattern of glabellar furrows,the weakly devel2 oped plectrum on preglabellar field and the general outline of pygidium,the new subspecies is closely related to Proceratopyge conif rons Wallerius(Westergaard,1948,p.5-6,pl.1,figs.7 -16),and differs from the latter mainly in having longer palpebral lobes,shorter transverse eye ridges,wider(sag.)occipital ring,broader(sag.)anterior border and broader pygidial axis with5axial rings rather than4axial rings of the latter.In general configuration of pygidium the new subspecies resembles to Proceratopyge si m ilis(Westergaard,1947,p.10-11,pl.2, fig.1),however,it can be readily discriminated from Swedish species mainly by its less tapered glabella,longer palpebral lobes,narrower(exsag.)posterolateral limbs and parallel forward an2 terior branches of facial sutures.Occurrence　The base of the Chefu Formation(lower part of Formosagnost us f ormosus2 B lackwel deria Z one);Jimachong,Wanshan District,eastern Guizhou,S.China.G enus Aplotaspis H enderson,1976Aplotaspis(Cataplotaspis)subgen.nov.1998　A plotaspis(Cataplotaspis),nom.nudum Yuan and Y in,p.140.Type species　A plotaspis(Cataplotaspis)quadrata subgen.et sp.nov.Etymology　Cat.2Cata(-Gr.)=downwards,under,below and combined with genus A plotaspis Henderson,1976,because the new subgenus occurs stratigraphically lower than A plotaspis.Species and subspecies assigned　A.(C.)caelata(Lazarenko,1968),A.(C.)laocha2tianensis (Yang ,1978),A .(C.)l.nobilis subsp.nov.,A .(C.)quadrata sp.nov., A.(C.)spiculata sp.nov.Diagnosis Ceratopygidae lacking pygidial spines.G labella tapering forward ,with low sagital ridge and a distinct median glabellar node.Shallow 3-4pairs of lateral glabellar fur 2rows.Occipital furrow with shallow lateral branches and isolated from axial furrows laterally.Occipital ring prominent ,with lateral occipital solution.Axial furrow well defined.Anterior border furrow and paradoublural furrow (or plectral furrow )shallow ,merging with anterior border furrow laterally ,curving backward medially and reaching axial furrow in front of glabel 2la.Anterior border narrow and flat ,extending backward medially and forming sagital plec 2trum.Palpebral lobes long ,banded ,semicircular in outline.Palpebral furrow shallow and dis 2tinct.Thorax of 9segments.Pygidium wide and short ,with well defined broad concave bor 2der.Axis with 4-6axial rings and a short postaxial ridge.Pleural area with 2-3pairs of pleural ribs ,of which the first pair is macropleural and extending onto the pygidial border.Discussion In general configuration of cranidium and pygidium the new subgenus bears the closest resemblance to A plotaspis Henderson ,with A plotaspis erugata (Whitehouse )as the type species (Whitehouse ,1939,p.239,pl.25,figs.6,7a ;Henderson ,1976,p.340,pl.48,figs.15-19;pl.49,figs.1-4),however ,it can be easily distinguished from the latter by its deeper axial furrow ,glabellar furrows ,occipital furrow ,its presence of median plectrum ,its presence of paradoublural furrow which merges with anterior border furrow laterally and curves backward medially ,its broader (tr.)fixed cheeks ,its longer palpebral lobes ,and its more dis 2tinct pleural as well as interpleural furrows on pleural area of pygidium.In the shape of glabel 2la ,the pattern of glabellar furrows ,the course of facial suture and the general configuration of pygidium the new subgenus is closely related to Pseudoyuepi ngia Chien ,with Pseu 2doyuepi ngia modesta as the type species (Chien ,1961,p.106,pl.5,figs.5-7),but it differs from the latter by many important features :(1)the cranidial furrows (axial furrow ,glabellar furrows and occipital furrow )are more distinct ;(2)the paradoublural furrow (or plectral fur 2row )and plectrum are well developed ;(3)the palpebral lobes are longer ,more posteriorly lo 2cated ;(4)the posterolateral limbs are narrower (exsag.);(5)the pygidium is shorter ,broad 2er ;(6)the pygidial axis is shorter ,less segmented ;and (7)the pygidial border is broader ,well demarcated.Pseudoyuepi ngia laochatianensis Yang (Yang ,1978,p.69-70,pl.3,figs.5-17)is here transfered to A plotapis (Cataplotaspis )subgen.nov.because of its well 2devel 2oped plectrum and paradoublural furrow ,the presence of 3pairs of more distinct lateral glabel 2lar furrows ,the shorter and broader pygidium with well demarcated broader border.Occurrence Early Late Cambrian ;South China.Aplotaspis (Cataplotaspis )quadrata subgen.et sp.nov.(Pl.Ⅰ,figs.7-17)Description Cranidium gently to moderately vaulted ,subquadrate in outline ,ratio of 771第2期袁金良等:刺尾虫科三叶虫的起源和早期演化width betweenβ2βto that betweenδ2δabout2∶3,gently arched anteriorly,ratio of length to width betweenδ2δabout5∶6.Axial furrows narrow and distinct.G labella subconical in out2 line,gently tapering posteriorly,more or less expanding opposite to S1,then slowly tapering forwardly,obtusely rounded anteriorly,occupying five2eighths of cranidial length(including occipital ring),with a low sagittal ridge and a small axial node located between S1and S1. Shallow lateral glabellar furrows1-4pairs:the S1is bifurcate and isolated from the axial fur2 rows,its anterior branches directed forward,its posterior branches slanting backward and in2 ward;the S2is oblique,placed in front of glabellar mid2length;the S3and S4are very shallow, slightly slanting forward,situated opposite to eye ridges.Occipital furrow deepening laterally, isolated from the axial furrows distally,shallowing and bifurcating medially,its posterior branches gently curving posterolaterally.Occiptial ring prominent,gently narrowing laterally, with subelliptical lateral occipital lobes.Frontal area wide,occupying about a quarter of crani2 dial length,subdivided by shallow anterior border furrow into narrow flat or somewhat up2 turned anterior border and wide gently downsloping preglabellar field.Anterior border narrow2 ing laterally,extending backward to form a narrow low plectrum medially.Paradoublural fur2 row present,merging with anterior border furrow laterally,bending backward and merging with axial furrow medially.Paradoublural lines curving and subparallel to sagittal plectrum. Fixed cheeks moderately broad,about two2fifths of glabellar width betweenδ2δ.Eye ridges low,oblique.Palpebral lobes long,banded,semicircular in outline,more than half as long as glabella,its posterior end slightly anterior to the level of occipital furrow.Anterior branches of facial sutures gently divergent forward;posterior branches slanting outward and backward.Py2 gidium transverse,subelliptical in outline,ratio of length to width about1∶2.1.Axis narrow and short,occupying about one fifth of pygidial width and three2fifths of pygidial length,with 4axial rings and a short postaxial ridge.Pleural area with3pairs of pleural ribs,of which the first pair is macropleural and extending onto the broad pygidial border,shallow pleural furrows 3pairs,2-3pairs of interpleural furrows obsolete,of which the first pair of pleural and inter2 pleural furrows extend close to the margin of the pygidium.Border furrow and doublural line distinct.Ontogenetic variation　Five cranidia figured on pl.Ⅰ,figs.7,8,9,11,15range in length from0.7mm(GPIN128904,pl.Ⅰ,fig.9)to5.7mm(GPIN128902,pl.Ⅰ,fig.7),during its ontogeny the following morphological changes can be observed:(1)the shape of glabella,usual2 ly narrow and long in juvenile cranidia,is becoming broad and short in adults;(2)An axial fur2 row,lateral glabellar furrows,occipital furrow and anterior border furrow are obscure in juve2 niles,but more distinct in adults;(3)An axial glabellar node,usually larger,posteriorly locat2 ed,becomes smaller,and more anteriorly in adults;(4)The frontal area,relatively short (sag.)in juveniles,is longer,well differentiated in adults;(5)Palpebral lobes,usually short, more advanced and far from glabella in juveniles,is longer,centroposteriorly placed in adults. Six pygidia figured on pl.Ⅰ,figs.10,12,13,14,16,17range in length from0.7mm(GPIN128905,pl.Ⅰ,fig.10)to3.7mm(GPIN128909,pl.Ⅰ,fig.14),during its ontogeny they show remarkable morphological changes.In the smallest pygidium axial furrow is obscure; pleural area and pygidial border are not differentiated;a broad posterior marginal indentation is developed.In juvenile pygidia(pl.Ⅰ,figs.12,16),pygidial axis is narrower;pygidial border is narrower and flat.In adults(pl.Ⅰ,figs.13,14,17),axis becomes shorter and broader;py2 gidial border is broader and somewhat concave and doublural line is developed.Occurrence　Lower part of the Chefu Formation(upper part of Formosagnost us2B lack2 wel deria Z one);Jimachong,Wanshan District,eastern Guizhou,S.China.Aplotaspis(Cataplotaspis)spiculata subgen.et sp.nov.(Pl.Ⅱ,figs.15-17)Description　Cranidium gently to moderately vaulted,subtrapezoidal in outline,ratio of width betweenβ2βto that betweenδ2δabout3∶5,ratio of length to width betweenδ2δabout1∶1.Axial furrow deep.G labella subcylindrical,pointed arched anteriorly,occupying about two thirds of cranidial length(including occipital ring),with a low sagittal ridge and a small axial node located between S1and S1.Three pairs of lateral glabellar furrows shallow,of which the S1is bifurcated and isolated from the axial furrows.Occipital furrow narrow and deepening lat2 erally,shallowing medially,isolated from axial furrows distally.Occipital ring prominent, slightly narrowing laterally.Frontal area wide,occupying about a quarter of cranidial length. Anterior border furrow narrow and shallow,bending backward in front of glabella.Anterior border narrow,slightly upturned,slightly narrowing lateraly,extending backward to form a triangular plectrum.Preglabellar field wider than anterior border,gently downsloping. Paradoublural furrow narrow and shallow,merging with anterior border furrow laterally and with axial furrow medially.Paradoublural line narrow and low.Fixed cheeks moderately broad.Eye ridges short and low.Palpebral lobes long,semicircular in outline,less than half as long as glabella except occipital ring,its posterior end opposite to mid2length of the S1.Pos2 terolateral limbs narrow(exsag.),strap2like to subtriangular.Posterior border furrow deep and broad,posterior border narrow,gently convex.Anterior branches of facial sutures running par2 allel or slightly diverging forward,posterior branches slanting outward and backward.Free cheek with short genal teral border broad,slightly teral border furrow distinct.Cheek area broad,gently downsloping.Eye lunate,with many small lenses.Eye fur2 row deep.Pygidium semielliptical in outline.Axis with6axial rings and a short postaxial ridge.Pleural area with3-4pairs of pleural ribs,of which the first pair is macropleural and extending onto the broad pygidial border.Doublure wide,with13-15terrace lines.Comparison　The new species differs from the tyep species A plotaspis(Cataplotaspis) quadrata sp.nov.mainly in possession of subcylindrical glabella with pointed arched anterior margin,smaller palpebral lobes and longer pygidium with6axial rings instead of4axial rings in the latter.In general configuration of cranidium and pygidium the new species bears the clos2。