陕西宁强原始锥石类五辐对称新属种的发现

陕西宁强宽川铺地区灯影组宽川铺段的原始锥石类Carinachitids中,新发现了五辐对称新属种--五分宁强锥石(新属、新种)Pentaconularia ningqiangensis gen.et sp.nov..本文对这一新属种进行了描记.结合前人发现的两辐对称、三辐对称、四辐对称的Carinachitids系列标...     

叠锥石

叠锥石是藻类生物长期沉积作用形成的特殊构造体 ,为叠层石中之一种。其所具有的形态特征与真正的生物化石有区别 ,又和沉积岩的层纹状构造不同 ,为一特殊观赏石石种。该石的基本层相互叠合形成锥柱体 ,柱体的不同形态及石体的分叉情况是对叠层石的分类与鉴定的重要依据。该类石由于受成岩作用的破坏较大 ,完整的生物遗体难于保存。笔者获得的叠锥石 ,主要产于二叠纪峨眉山玄武岩顶部与侏罗纪相交的过度带的喷出岩碎屑层中。其底层叠层与柱体完好 ,层理形态清晰 ,集合体为黑黄色。该石具有美丽的造型 ,完好的生物遗迹 ,别具一格的锰铁与泥质…     

陕南早寒武世西乡化石库原始锥石类Carinachitids新材料及其形态功能分析

近期在西乡化石库中发现了原始锥石类 Carinachites tetrasulcatus 新材料.与以往 C.tetrasulcatus 所不同的是,其角沟窄且浅,不但有呈现出张开状态的角沟,还发现有呈现出闭合状态的角沟化石材料.锥面具有清晰的横肋,角沟处未见横纹.最重要的是发现固着端组织结构的保存,据此推断原始锥石类...     

一种类别不明的化石—三瓣石

１９７８年笔者首次发现一种类别不明的微体古动物壳体化石，其长度一不足１ｍｍ，横切面呈三瓣状，命名为三瓣石。现有的标本获自湖中下石炭统，同一层位还产珊瑚、腕足类化石。经过十多年的反复观察，切片研究等，三瓣石的原始壳质，结构构造，形态特征已基本弄清。按初步制定的形态分类方案，现有的上千个标本至少可分为２组３属约３０个种，本文暂描述其中的１３个种。     

记述原始锥石类中的一个新属种

本文描述了我国四川峨嵋灯影组麦地坪段原始锥石类中的一个罕见的具有三个柱面的Ｅｍｅｉｃｏｎｕｌａｒｉａｔｒｉｇｅｍｍｅｇｅｎ．ｅｔｓｐ．ｎｏｖ．。并与具有四个柱面的Ｃａｒｉｎａｃｈｉｔｉｄｓ和六个柱面的Ｈｅｘａｎｇｕｌａｃｏｎｕｌａｒｉｄｓ进行了比较讨论。经扫描电镜观察,该属种壳体由二层组成。内层由棱柱状胶结物组成,外层由微粒状磷酸盐颗粒组成。它们被认为是经过改造了的原生磷酸盐质壳壁。     

一种类别不明的化石──三瓣石（Tripetita）

１９７８年笔者首次发现一种类别不明的微体古动物壳体化石,其长度一般不足１ｍｍ;横切面呈三瓣状,命名为三瓣石（Ｔｒｉｐｅｔｉｔａ）。现有的标本获自湘中下石炭统,同一层位还产珊瑚、腕足类化石。经过十多年的反复观察、切片研究等,三瓣石的原始壳质、结构构造、形态特征已基本弄清。按初步制定的形态分类方案,现有的上千个标本至少可分为２组３属约３０个种。本文暂描述其中的１３个种。     

陕西南部早寒武世原始锥石类carinachitids两新种记述

对陕西宁强宽川铺地区灯影组宽川铺段原始锥石类carinachitids两个新种Emeiconularia amplicanalis sp.nov.和Carinachites platus sp.nov.进行了记述。外表形态多样、个体大小悬殊的两辐对称、三辐对称和四辐对称的carinachitids系列标本的发现,揭示了陕南地区早寒武世丰富多样的carinachitids生命世界。三辐射对称的Emeiconularia在四川峨眉及陕西南部的震旦-寒武系界线附近都有分布,因而对前寒武纪—寒武纪跨界地层具有划分对比意义。两新种的发现无疑增加了我们对早期锥石类多样性的认识,为证实多样性的刺细胞动物在早寒武世早期已经存在的假说提供了新线索。     

一个新的无脊椎动物门——锥石门

提起锥石类,大家也许会想到它属于腔肠动物门钵水母纲。自从基得连1937年的工作以后,大多数古生物学家都持这种观点,国内有关的教科书也采用这种分类。其实,自上世纪初首次发现锥石化石以来,关于它的分类问题就一直争论不休。罗德尼·费尔德曼和洛伦·巴布科克最近的研究表明,锥石的外骨骼构造与已知的其它化石和现生各门类动物都截然不同,     

陕南寒武纪西乡化石库的马哈螺和棱管壳研究

对陕南西乡化石库发现的马哈螺类化石和棱管壳类化石做了统计和描述,补充了马哈螺类新的属征,建立新种西乡拟鳞锥Ramentoides xixiangensis sp. nov.。马哈螺和棱管壳表面装饰存在差异,并非同一物种上掉落的骨片,本文展示的马哈螺新的特征与"骨针壳"假说存在矛盾,马哈螺在形态上表现出软体动物单板类最原始的特征,而棱管壳则与halkieriids存在密切的亲缘关系。本文报道了马哈螺类化石的新形态,丰富了对马哈螺类和棱管壳类的认识,对确立马哈螺和棱管壳的亲缘关系和分类位置提供了新的材料。     

四川江油三叠纪锥石化石新材料

锥石类化石的生物系统分类位置还不十分肯定,但目前多数人认为应该归入腔肠动物门真水母纲。据目前所知,我国发现的锥石化石主要产于晚古生代。本文所描述的锥石化石,产于四川省江油县马鞍塘车站附近的晚三叠世卡尼期地层。与该化石共生的主要是双壳类Myophoria(Co-     

Redescription of Hexaconularia He and Yang, 1986 (Lower Cambrian, South China): implications for the affinities of conulariid-like small shelly fossils

Abstract:  Hexaconularia , a Lower Cambrian small shelly fossil (SSF) that has been allied with conulariids and scyphozoan cnidarians, is redescribed and refigured. A salient feature of this monospecific genus is the presence of distinct apical and abapical regions. The apical region probably represents an embryonic shell that apparently lacked a basal attachment structure. Comparisons of this feature with the apical end of the smallest known conulariids and with conulariids terminating in an apical wall (schott) reveal substantial differences in structure and ornamentation. Differences in apical anatomy between conulariids and Arthrochites , possibly the nearest SSF relative of Hexaconularia , are also apparent. Comparisons of Hexaconularia with Punctatus , an SSF taxon showing distinct apical and abapical regions in both posthatching specimens and prehatching embryos, suggest that the early development of Hexaconularia was direct. These results have important implications for hypotheses of a conulariid/scyphozoan affinity for Hexaconularia and its possible SSF relatives, and they suggest that Hexaconularia -bearing strata may yield prehatching embryos of this genus.     

Making Tracks

The science of ichnology has grown out of its early phase of infancy, but has not yet entered into the stage of senility. As long as we ichnologists continue playing around with trace fossils just for the fun of it while at the same time employing trace fossils as serious tools in solving geologic problems, our science will continue to be a dynamic and exciting pursuit for many years to come.     

A critique of the chronometric evidence for hominid fossils: I. Africa and the Near East 500-50 ka

The chronometric dating evidence for all hominid fossils from Africa and the Near East that have previously been dated to 500-50 ka is critically assessed using the concept of chronometric hygiene, and these dates are revised using Bayesian statistical analyses where possible. Sixteen relevant hominid sites lacking chronometric evidence are briefly discussed. Chronometric evidence from 37 sites is assessed in detail. The dates for many hominid fossils are poorly constrained, with a number dated by comparisons of faunal assemblages-a method that does not have good chronological resolution for much of the last million years. For sites with stratigraphic sequences of dates, it is generally possible to refine the dating, but in some cases, the revised chronology is less precise than previous chronologies. Fossils over 200 ka in age tend to be poorly dated, but for the last 200 kyr, dating is better due to the availability of electron-spin-resonance and thermoluminescence dating. Consideration of the chronologies favored by the proponents of the out-of-Africa and multiregional hypotheses of human evolution shows their selectivity. The chronological assessment of the fossils here is compatible with either hypothesis. If evolutionary schemes that do not rely on the morphology of the hominid fossils to decide the sequence of fossils are to be built, then further dating is required, alongside full publication of existing dates.     

Adolescent archaics or adult moderns? Le Moustier 1 as a model for estimating the age at death of fragmentary supraorbital fossils in the modern human origins debate.

This study documents and examines selected implications of the adolescent supraorbital anatomy of the Le Moustier 1 Neandertal. Le Moustier's supraorbital morphology conforms to that expected of an adolescent Neandertal but indicates that significant development of the adult Neandertal torus occurs late in ontogeny. As the best preserved adolescent from the Late Pleistocene, Le Moustier 1's anatomy is used to help distinguish adolescent from adult anatomy in two cases of fragmentary supraorbital fossils, the Vindija late Neandertals and KRM 16425 from Klasies River Mouth (South Africa). It has been suggested that the modern-like aspects of the Vindija and Klasies supraorbital fossils are a function of developmental age rather than evolution. Although Le Moustier 1's anatomy does indicate that two of the Vindija fossils are adolescent; these two fossils have already been excluded from studies that demonstrate transitional aspects of the Vindija adult supraorbitals. Results of an analysis of KRM 16425 in light of Le Moustier 1 are more ambiguous. KRM 16425 is clearly not a Neandertal, but its morphology suggests that it may be an adolescent form of such late archaic Africans like Florisbad or Ngaloba. Both the Vindija and Klasies River Mouth cases highlight the need to be wary of confusing adolescent anatomy with modernity.     

The depositional context of the early upper paleolithic human fossils from the Koneprusy (Zlatý kůn) and Mladec caves, Czech republic

The caves of Mladec I and II (Moravia) and Koneprusy (Bohemia) are principal hominid Early Upper Paleolithic sites in Central Europe that require a complex reconsideration from several viewpoints. The focus of this paper is on the depositional context of human fossils, which is clearer from the documentation of Koneprusy, excavated during the 1950s, than from the early reports about Mladec. Both caves are multi-floor underground karstic systems penetrated by vertical fissures and chimneys, where the fossils were found in restricted areas, related to debris cones accumulated under the chimneys. These associations are confirmed using Surfer reconstruction of the original fillings. It appears certain for Koneprusy and highly probable for Mladec that the fossils fell in through the chimneys. This does not mean that living animals and humans never entered the interior of the caves (traces of gnawing by hyenas are visible), but it makes it unlikely that the human paleontological accumulations were the result of human activity within the cave chambers.     

寒武纪早期宽川铺生物群中圆管螺化石显微结构及显微谱学分析

陕南寒武系底部宽川铺组不仅保存了大量的小壳化石,还以磷酸盐化的方式立体保存了多种软躯体动物的胚胎和成体化石,为研究早期动物矿化模式、个体发育方式以及动物躯体构型的早期辐射过程提供了非常关键的信息。然而宽川铺生物群的研究大多聚焦于化石系统分类及亲缘关系探索,对生物群的沉积背景、埋藏过程和保存模式的分析甚少。本文以宽川铺生物群的核心产出层位——陕西省西乡县大河镇宽川铺组下部磷质碎屑灰岩为研究对象,对其中的一类管状化石圆管螺及其围岩进行了显微结构学和显微谱学综合分析,获得了化石显微结构和关键结构对应的元素、矿物成分等信息,讨论了管状化石圆管螺的埋藏过程和保存模式,并在此基础上对其生物学特征进行了初步探讨。该研究对理解宽川铺生物群的埋藏机制提供了新的线索。     

甘肃临夏盆地的渐新世巨犀化石

描述了 2种巨犀化石 :霍尔果斯准噶尔巨犀 (Dzungariotheriumorgosense)和牙沟副巨犀(新种 ) (Paraceratheriumyagouensesp .nov.)。新种的主要特征是 :个体小 ;上颊齿齿冠高 ,有薄层白垩质覆盖 ;DP2～M1反前刺大 ,原尖后收缩沟明显 ,次尖有深的前收缩沟 ,中谷和后凹中常有附属小柱等。巨犀的演化历史可能比过去想象的更复杂。Indricotherium、Dzungariotherium和Paraceratherium为代表不同进化水平和支系的 3个属 ,不应合并为Paraceratherium一属。牙沟含巨犀化石层位的地质时代为晚渐新世。     

ENIGMATIC WORM-LIKE ORGANISMS FROM THE UPPER DEVONIAN OF NEW YORK: AN APPARENT EXAMPLE OF EDIACARAN-LIKE PRESERVATION

Abstract:  The supposed polychaete annelid Protonympha salicifolia , from the Upper Devonian (Frasnian) of New York State, USA, is redescribed. P .  salicifolia has a bilateral and segmented body, but appears to have a 'mattress-like' construction with blade-like extensions along the margins. The affinities of P. salicifolia remain unresolved, but a proposed relationship to the annelids is unlikely. The preservation of the three known fossils, as mouldic imprints in sandstones, is strongly reminiscent of the circumstances associated with Ediacaran fossilization, and as such is an anomalous occurrence of such soft-part preservation in Phanerozoic sediments. Material associated with these enigmatic fossils has been referred to Palaeochaeta devonica , and also compared with the annelids. Such an assignment is also rejected. These fossils appear to be arthropodan, and are possibly myriapods. A supposed example of Protonympha (' P '.  marcellensis ) from the Middle Devonian of New York State is now excluded from this genus, and it may be a crustacean.     

辽南前寒武系兴民村组“类水母”化石新认识

近年来,由于大量可靠的前寒武纪多细胞动物化石的发现,激起了各国学者在前寒武纪地层中寻找多细胞动物化石及其遗迹的热情。华北辽东半岛南部新元古界兴民村组"类水母"化石自上个世纪80年代中期发现以来,一直被大多数学者认为是可能的后生动物化石。然而,笔者通过对"类水母"化石的形态学及生长模式的研究,认为辽南前寒武系兴民村组"类水母"化石可能并非多细胞动物化石,而是一类亲缘关系不明的不具备运动能力的底栖生物化石,该化石具有无限的线性增长方式。关于其生物学属性需要进行进一步的研究。