晚前寒武纪重要生物事件与事件地层界线

本文以生物绝灭及生物新生为主线,论述了国内外晚前寒武纪的几个主要生物出现事件——宏观藻类出现事件;后生软躯体动物出现与绝灭事件;带壳动物出现事件.通过这些生物事件,讨论了震旦-寒武系界线目前存在的几种看法,指出了震旦-寒武系界线选在A点是有足够的生物学基础的,同时此界线也是一条重要的事件地层界线.     

Guanling Biota: A Marker of Triassic Biotic Recovery from the end-Permian Extinction in the Ancient Guizhou Sea

After a slow recovery from the end-Permian extinction during the Early Triassic and rapid radiation in the Middle Triassic, evolution of organisms reached a new peak phase in the Late Triassic. The Guanling Biota from the Wayao Member （conodont Paragondolella polygnathiformis Zone）, Falang Formation, Xinpu, Guanling County, Guizhou Province, southwestern China corresponds to this peak that marks the full recovery from the end-Permian extinction of marine ecosystems. The biota is of high diversity, containing well preserved and completely articulated skeletons of vertebrates comprising marine reptiles, fishes, and invertebrates including crinoids, ammonites, bivalves, and other fossils, and is one of the best examples of marine ecosystem records in life history. The fossil marine reptiles and crinoids are most significant in this biota, especially the marine reptiles, which provide an important link between the Triassic Pacific and Tethys, and between Triassic basal forms and the Jurassic-Cretaceous marine top predators. The most remarkable fossils are the large completely articulated ichthyosaur skeletons up to and more than 10 m, and the first recorded thalattosaurs and placodonts in China. Following our review, of the 17 named reptilian taxa the eight listed here are considered to be valid： three ichthyosaurs （Qianichthyosaurus zhoui Li, 1999; Guizhouichthyosaurus tangae Cao and Luo in Yin et al., 2000, Guanlingsaurus liangae Yin in Yin et al., 2000）, three thalattosaurs （Anshunsaurus huangguoshuensis Liu, 1999, Xinpusaurus suni Yin in Yin et al., 2000, Xinpusaurus kohi Jiang et al., 2004）, and two placodonts （Sinocyamodus xinpuensis Li, 2000, Psephochelys polyosteoderma Li and Rieppel, 2002）. Mixosaurus guanlingensis Cao in Yin et al., 2000 might be a junior synonym of Qianichthyosaurus zhoui Li, 1999, and Cymbospondylus asiaticus Li and You, 2002 and Panjiangsaurus epicharis Chen and Cheng, 2003 might be junior synonyms of Guizhouichthyosaurus tangae Cao and Luo in Yin et al., 2000. It needs to re-describe the holotypes after a complete preparation for clarifying the taxonomic status of Typicusichthyosaurus tsaihuae Yu in Yin et al., 2000, Xinpusaurus bamaolinensis Cheng, 2003, Neosinosaurus hoangi （Zhou in Yin et al., 2000）, Wayaosaurus geei Zhou in Yin et al., 2000, Wayaosaurus bellus Zhou in Yin et al., 2000 and Placochelys ？ minutus Yin and Luo in Yin et al., 2000.     

中国水生蜥与潜龙名称合法性之争

热河生物群中有一种水生爬行动物,以长颈、长尾、小头颅为主要特征。在研究中,不同学者使用了不同的学名,构成了同物异名。简要回顾它的研究历史,主要讨论究竟哪一个学名是合法有效名称。根据国际动物学命名法规,认为中国水生蜥(Sinohydrosaurus)命名在先,是合法有效名称,而潜龙(Hyphalosaurus)为无效名称,应当废弃。     

安徽省嘉山县官山沉积型坡缕石的矿物学研究

官山坡缕石矿物为典型的沉积成因,结晶程度低、化学成分较复杂,以富Fe_2O_3为特征。矿物在380～580℃热脱水过程中TG曲线近于连续,因此,推测其存在结晶水(OH_2)和结构水(OH)同时脱失的温度区域。X射线粉晶衍射数据中,矿物的(121)、(161)面网衍射不同程度地发生分裂,应属于单斜晶系,但单斜角β近于90°。矿物红外光谱特征和摩叶根标谱类似,只是由于Mg~(2+)、Al~(3+)等八面体阳离子占位率的变化引起部分振动频数的微小飘移。     

论淮南生物群

淮南生物群 (Huainan Biota)产于安徽淮南地区新元古代淮南群中 ,由宏观藻类 Chuaria- Tawuia组合和蠕形动物 Pararenicola- Paleolina组合组成 ,可与加拿大西北麦肯齐山新元古代小达尔群 (L ittle Dal Group)小达尔生物群 (L ittle Dal Biota)对比 ,为新元古代大冰期前的一个特有生物群落 ,地质时代为前震旦纪 (本文的震旦纪即目前的南华纪至震旦纪 ) ,时限约为 85 0— 75 0 Ma,从而将前人所定淮南生物群为青白口纪至震旦纪的时代结论修订为前震旦纪。这对我国乃至国际上新元古代地层层序的重新划分与对比 ,以及新元古代早期生命演化研究等都具有重大的理论意义和实际价值。文中还着重论述了淮南生物群的组合特征和特定的生物发展阶段 ,而区别于青白口纪和震旦纪的生物群落 ,并通过洲际对比 ,讨论了淮南生物群的地层学意义     

A New Arthropod, Guangweicaris Luo, Fu et Hu gen. nov. from the Early Cambrian Guanshan Fauna, Kunming, China

The Guanshan Fauna is a soft-bodied fauna dominated by arthropods （including trilobites, trilobitoides, Tuzoia, Isoxys, and bradorids） in association with priapulids, brachiopods, anomalocaridids, vetulicoliids, sponges, chancellorids, and echinoderms. This paper reports and describes a new arthropod from the yellowish green mudstone at the lower part of the Wulongqing Formation, Canglangpuan Stage, Lower Cambrian in Kunming, Yunnan, China. The stratigraphic and geographic distribution, classification, fossil preservation, life style of this new arthropod and comparisons with other fossil arthropods are also discussed in details. The discovery and research of the non-mineralized arthropod, Guangweicaris Luo, Fu et Hu gen. nov. from the Guanshan Fauna adds new members to the taxonomic list and provides new information to the evolution of early arthropods. Furthermore, this study would shed new light into the ＂Cambrian Explosion＂ and the evolution of early life.     

黔东北震旦纪陡山沱晚期庙河型生物群的生态特征及埋藏环境初探

贵州省东北部江口县桃映震旦纪陡山沱组上部发现的庙河型生物群,包括宏体藻类、可能的后生动物、遗迹化石以及其它生物化石等,进一步证实这类宏体生物群在扬子地区震旦纪陡山沱晚期有较为广泛的分布。通过与鄂西庙河生物群、皖南蓝田植物群的对比,震旦纪陡山沱晚期宏体生物群的生活环境主要为开阔浅海向台缘斜坡相过渡地带。通过对黔东北庙河型生物群的研究,认为陡山沱晚期的宏体生物群为以营固着生活方式为主,生活于透光性较好、具有一定水动力条件和一定含氧量的相对静水贫氧浅海环境;其固着基底为富含水份的未固结的粥性-软质基底。这些宏体生物群多呈半漂浮状竖立于海底,构成初步的“海底草原”,为生物群中依赖一定氧而生活、生长和繁殖的动物提供了必要的支持。生物死亡后,大部分生物躯体倒伏于沉积物表面,在贫氧和较快沉积速率的沉积环境中,生物遗体被较好保存,并很快被沉积物所埋藏。随着沉积物的增厚,生物遗体被完全封闭,导致生物遗体腐烂和分解过程终止,使其得以很好保存。较快的沉积速率、贫氧和相对平静水体的环境是生物群得以很好保存的重要因素。     

冀北承德地区热河生物群化石组合特征及其地质意义

冀北承德与辽西建昌-义县一带是热河生物群化石的命名地,产有丰富的无脊椎动物和脊椎动物化石,以及早期被子植物化石,是探讨鸟类,哺乳类和被子植物起源的重要地区,引起了国内外古生物学家的高度关注和各国媒体的广泛报道.冀北承德地区陆相晚期中生代地层的张家口组-大北沟组-大店子组的层位要低于辽西地区的义县组,时代也更老.该区所产珍稀无脊椎动物与珍稀脊椎动物化石的时代除义县期外要老于辽西义县组,这对探讨热河生物群的起源与演化,特别是软骨硬鳞鱼和真骨鱼类的演化,两栖类的系统分类,鸟类的起源,原始哺乳类的进化,以及被子植物的起源等都具有重大的理论意义.     

辽宁西部早白垩世九佛堂组热河鸟类一新属种

辽宁朝阳早白垩世九佛堂组发现了一种新型热河鸟类化石。该化石不仅具有热河鸟类的典型特征,如尾椎由约28枚未愈合的椎体组成,中后部尾椎前后方向明显拉长;前颌骨无牙齿;齿骨后缘较直,靠近吻端腹侧明显膨大等,同时具有不同于其他已知热河鸟类的独具特征组合,如肱骨三角肌脊相对不发育;第三掌骨较直,与第二掌骨间距较小;后肢第一趾爪最大;尾椎脉弧、关节突不发育等。根据该化石的独特性及与其他热河鸟类特征对比研究,笔者建立了热河鸟类新属、新种：直掌内蒙鸟（Neimengornis rectusmim gen.et sp.nov.）。直掌内蒙鸟（新属、新种）的发现进一步丰富了热河鸟类的属种类群,为研究这一类群的形态特征和属种分异等提供了新的化石证据。     

辽西热河生物群箭蜓科昆虫新类群

描述了箭蜓科(Gomphidae)一新属种—宽翅辽宁澜箭蜓(Liaoninglanthus latusgen.et sp.nov.)及新属一未定种(Liaoninglanthus.sp.),还对义县光箭蜓(Liogomphus yixianensisRen et Gao,1996)进行了补充描述。化石全部采自辽西北票黄半吉沟义县组下部(晚侏罗世晚期—早白垩世)。