Provincialism of the late Middle through middle Late Cambrian paraconodonts and protoconodonts

Quantitative paleoprovincialism is studied, using a coefficient of similarity (CS) formula. The results indicate that the provincialism of the late Middle through middle Late Cambrian paraconodonts and protoconodonts did exist. The provincialism of Ordovician conodonts can be traced back to late Middle Cambrian. The North China Province and South China Province can be recognized in late Middle Cambrian, whereas the North China Province, South China Province and Balitca Province can be recognized respectively in early Late Cambrian and middle Late Cambrian. The possibility that the larger units of provincialism, i.e. Faunal Regions existed in the areas mentioned above is discussed. It is inferred that the Midcontinent Faunal Region and the Atlantic Faunal Region had existed in early Late Cambrian and middle Late Cambrian. The North China Province was the secondary unit of provincialism in the Midcontinent Faunal Region, while the Baltica Province was that in the Atlantic Faunal Region. The South China Province is the secondary unit of provincialism between the two largest units of provincialism. Moreover, the comparison with the trilobite provincialism which has been accumulated on a solid basis of research is made, and the paleogeographic positions of North China Massif, South China Massif and Tarim Massif are revised.     

Early Cambrian phosphatized blastula- and gastrula-stage animal fossils from southern Shaanxi

Marine invertebrate animal embryos and their early developmental products are of great significance to the study of taxonomy and phylogeny of early animals. A great number of phosphatized globular fossils were collected fromthe early Cambrian Kuanchuanpu Member (upper Dengying Formation), southern Shaanxi, and a nearly complete develo-pmental sequence—from a fertilized egg, via blastodisc formation, blastula development, blastodisc enlargement toward gastrulae, to tissue differentiation—can be discerned in this collection. This discovery provides unmatchable material for studies on the origin, taxonomy, radiation, and ontogeny of early metazoans.     

Early Cambrian eodiscoid trilobites of the Yangtze Platform and their stratigraphic implications

Analysis of the taxonomy and stratigraphic distribution of the Early Cambrian eodiscoid trilobites of the Yangtze Platform indicates that species of Tsunyidiscus and Hupeidiscus can be used for biostratigraphic correlation. T. aclis occurs only in the lower Qiongzhusian, T. armatus occurs in the lower and middle Qiongzhusian, while T. niutitangensis and T. tingi occur mainly in the middle and upper Qiongzhusian, with only T. tingi extending upward into the lower Canglangpuian. H. orientalis first appears in the upper Qiongzhusian, reaching peak abundance in the lower Canglangpuian and becoming extinct above the Drepanuroides Zone. Biostratigraphic and lithostratigraphic correlations indicate that the limestone in the lower part of the Mingxinsi Formation, the Upper Member of Jiumenchong Formation, and the upper part of the Middle Member of the Huangbailing Formation, can be correlated with each other as Hupediscus, an index fossil of the lower Canglangpuian, is abundant in all these units. The lower part of the Niutitang and Jiumenchong formations in eastern Guizhou, which mainly represent Qiongzhusian strata, can be correlated with the Lower Member of the Huangbailing Formation. The basal part of the Niutitang Formation, which may be equivalent to the Upper Meishucunian Shiyantou Formation in eastern Yunnan, is very condensed. Well-preserved sponge faunas and non-mineralized fossils in the lower part of the Niutitang and Hetang formations are not older than Qiongzhusian in age.     

Phosphatized embryo fossils from the Cambrian explosion

The earliest Cambrian (Meishucunian) phosphatized metazoanOlivooides from the Yangtze platform is represented by dierent developmental stages: from blastula through possible gastrula to tissue differentiation and finally to the hatched animals. The fossilization of embryos opens a new field in palaeontologypalaeoembryology. Embryological studies will be of importance for the understanding of ontogeny and phylogeny of metazoans from the Cambrian explosion.     

Lower Cambrian small shelly faunas from Zhejiang (China)and their biostratigraphical implications

Despite a long history of research on the Early Cambrian in China most available data on small skeletal fossils concern fossil associations of the shallow carbonate platform. Information on skeletal fossils from marginal shelf environments of the Yangtze Platform is scanty, which may reflect the rarity of fossils in deeper sedimentary environments but is also due to limitation of carbonate distribution and outcrops, difficulties in fossil extraction, and a general research focus on the Precambrian-Cambrian boundary beds on the carbonate platform. Here we present a documentation of Meishucunian to Qiongzhusian small skeletal fossils from the lower Hetang Formation and the chert unit at its base from the Jiangshan region, Zhejiang Province, representing a relatively deep shelf environment compared to the inner shelf region. The earliest association (Meishucunian) from the chert unit underlying the Hetang Formation is mainly characterized by the occurrence of Protohertzina anabarica, P. unguliformis, Fengzuella zhejiangensis, and Kaiyangites novilis, which differs somewhat in composition from SSF-associations of typical inner shelf deposits. The enigmatic skeletal fossil Fengzuella zhejiangensis, which exhibits an unusual secretional growth mode previously unrecognized from the Early Cambrian, is described in detail. A younger (Qiongzhusian) fossil association contains numerous arthropod remains, such as disarticulated spines of arthropods (Jiangshanodus- and Kijacus-type), which have previously been considered as conodont-like fossils, and bradoriid valves.     

Vermicular fossils in the Early Cambrian Xidashan Formation in the Quruqtagh region of Xinjiang, China

Large amounts of vermicular fossils and a minor amount of sponge animal fossils have been found in the Early Cambrian Xidashan Formation in the region of Quruqtagh, Xinjiang. Vermicular fossils are generally more than 50 mm long and 0.3?1.4 mm wide; their wrinkled lamellae are microfine with 3?10 pieces within the length of every each millimeter. The fossils are considered to be Sabellidites cambriensis Sokolov (1965). The Xidashan Formation is the highest stratum in which Sabellidites occur, as has been so far reported.     

Speciation of the genus Arthricocephalus Bergeron, 1899 (Trilobita) from the late Early Cambrian and its stratigraphic significance

The genus Arthricocephalus Bergeron, 1899 is revised, and Halipanktos Balker & Peel, 1997 is suggested here as a senior synonym. The subgenus Arthricocephalus (Arthricocephalites) Chien & Lin in Lu et al. , 1974 is considered as a separate genus. Of the 20 previously assigned species of Arthricocephaius (Arthricocephalus) Bergeron, 1899, Arthricocephalus (Arthricocephalites) Chien & Lin in Lu et al. , 1974, Arthricocephalus (Euarthricocephalus) Ju, 1983 are lumped into eight species. The speciation trend of Arthricocephalus and Arthricocephalites is demonstrated based on their stratigraphic occurrences. It not only enhances the resolution of the biostatigraphic zonation in the uppermost Lower Cambrian, but also represents a potential candidate to define the Duyunian stage. The base of the stage is suggested at the first appearance datum (FAD) of Arthricocephalus chauveaui Bergeron, 1899 within the evolutionary lineage from Ar. jiangkouensis Yin in Yin & Li, 1978 to Ar. chauveaui in a global scale.     

寒武早期泥质基底腕足动物的生活策略——来自澄江动物群的证据

目的 系统分析滇东泥质基底澄江化石库腕足动物的生活方式.方法 依据澄江化石库丰富的腕足动物资料,论证寒武纪早期泥质基底腕足动物的生活策略.结果 寒武纪早期泥质基底上腕足动物的生活方式主要包括肉茎附着型(pedicle-anchoring or pedicle-attaching)、自由平躺型(free-lying)、假内栖型(qusi-infaunal)和表栖粘附型(cemented epifaunal),肉茎附着型是早寒武世腕足动物生活的最普遍的型式.结论 空间生态分析显示,早寒武世滇东海盆中,腕足动物的分布已经具有一定的空间层次性,不同的腕足类型占据了不同的生态位,形成了比较复杂的空间群落结构.     

贵州早寒武世黑色页岩地球化学特征及其意义

贵州早寒武世早期普遍存在一套黑色页岩。通过对麻江羊跳、铜仁、遵义中南、遵义松林小竹、天柱大公塘剖面实地考察与地球化学分析,认为贵州早寒武世黑色页岩是在缺氧环境下,热水沉积为主导,同时受陆源强烈影响,是海水、生物和地球深部物质共同作用下形成的.     

Trace element geochemistry of the Lower Cambrian black rock series from northwestern Hunan, South China

Samples of black rock series collected from the Lower Cambrian Niutitang Formation, northwestern Hunan Province, China, were analyzed for trace elements.The trace element geochemical characteristics of the ore layer (high enrichments of Ni, Mo, V, U, Cu, Pb, Zn, Cd, Tl and Ba; high U/Th ratios and LREE-enriched patterns with positive Eu and Y anomalies) support the assumption that the Ni-Mo polymetallic layer is of submarine hydrothermal origin.High field strength elements (HFSE) and lithophile elements such as Nb, Ta, Zr, Hf, Li, Be, Rb, Cs, Th and Sc are remarkably higher in the upper unit than those in the lower unit of the Niutitang Formation.These features may reflect that hydrothermal contributions were diminished, and terrigenous constituents were increased in the sediments of the upper unit of the Niutitang Formation.     

Sponge fossil assemblage from the Early Cambrian Hetang Formation in southern Anhui

Abundant well-preserved large articulated sponge fossils and isolated spicules have been reported from the Early Cambrian Hetang Formation, southern Anhui Province. This unique epifaunal fossil assemblage dominated by articulated sponge fossils is called the Xidi Sponge Fauna. The sponge fauna lived in a quiet oxygenic environment below the storm wave base. Bloom of phytoplankton and rapid sedimentation rate resulted in the deposition of the black shales. Sufficient food supply, lack of other competitors, abundant ecological niches, and demand for oxygen during early Cambrian were in favor of the diversification and evolution of large sponges in the Early Cambrian.     

Microstructure and functional morphology of the Early Cambrian problematical fossil Rhombocorniculum

Rhombocorniculum cancellatum from the Lower Cambrian of southern Shaanxi Province (South China) is represented by the dextral and sinistral tooth-like sclerites (both in nearly equal numbers), indicating that the body plan of the organism with these sclerites probably was bilaterian. The main feature of the microstructure of the sclerites is the presence of longitudinally arranged, mutually contiguous hollow tubules, the shared walls consisting of microcrystalline apatite. In transverse cross sections, the sclerite wall mainly exhibits a spongy structure, with pore size decreasing adapically. Functional morphological analysis indicates that the sclerites serve as a defensive rather than a grasping function.     

δ13Ccarb and Ceanom excursions in the post-glacial Neoproterozoic and Early Cambrian interval in Guizhou,South China

Secular δ 13Ccarb and Ceanom profiles in the post-glacial Neoproterozoic and Early Cambrian interval are reported from Guizhou on the southeasten border of the Yangtze platform, South China. Overall, the δ 13Ccarb profile drifts to negative values in the post-glacial Nantuo and lower to middle Doushantuo Formations, and then to positive values in the upper Doushantuo and Dengying Formations of Neoproterozoic, followed by negative values in the Lower Cambrian Gezhongwu and Niutitang Formations. A detailed investigation of the relationship between the δ 13Ccarb and Ceanom profiles reveals that the main anoxic and oxic episodes are coupled with negative and positive δ 13Ccarb values, respectively. This may suggest a control of alternation between ocean stratification and mixing on variations in 13C abundance in the ancient ocean of the investigated areas.     

Preliminary notes on softbodied fossil concentrations from the Early Cambrian Chengjiang deposits

The Chengjiang fauna has played a pivotal role in our understanding of the origin and diversification of metazoans since its discovery in 1984. To date, this fauna has been documented as consisting of 121 genera with 140 species belonging to 24 phyla[1-27]. The geo- graphic distribution of the Chengjiang fauna has been expanded from Chengjiang County to eastern Yunnan Province including Haikou, Malong, Yiliang, Anning and elsewhere[25-33], with about 20 localities in to- tal[25,33]. Succes…     

Speciation of the genus Arthricocephalus Bergeron, 1899 (Trilobita) from the late Early Cambrian and its stratigraphic significance

The genus Arthricocephalus Bergeron, 1899 is revised, and Halipanktos Balker & Peel, 1997 is suggested here as a senior synonym. The subgenus Arthricocephalus (Arthricocephalites) Chien & Lin in Lu et al., 1974 is considered as a separate genus. Of the 20 previously assigned species of Arthricocephalus (Arthricocephalus) Bergeron, 1899, Arthricocephalus (Arthricocephalites) Chien & Lin in Lu et al., 1974, Arthricocephalus (Euarthricocephalus) Ju, 1983 are lumped into eight species. The speciation trend of Arthricocephalus and Arthricocephalites is demonstrated based on their stratigraphic occurrences. It not only enhances the resolution of the biostatigraphic zonation in the uppermost Lower Cambrian, but also represents a potential candidate to define the Duyunian stage. The base of the stage is suggested at the first appearance datum (FAD) of Arthricocephalus chauveaui Bergeron, 1899 within the evolutionary lineage from Ar. jiangkouensis Yin in Yin & Li,1978 to Ar. chauveaui in a global scale.     

Speciation of the genus Arthricocephalus Bergeron, 1899 (Trilobita) from the late Early Cambrian and its stratigraphic significance

The genus Arthricocephalus Bergeron, 1899 is revised, and Halipanktos Balker & Peel, 1997 is suggested here as a senior synonym. The subgenus Arthricocephalus (Arthricocephalites) Chien & Lin in Lu et al., 1974 is considered as a separate genus. Of the 20 previously assigned species of Arthricocephalus (Arthricocephalus) Bergeron, 1899, Arthricocephalus (Arthricocephalites) Chien & Lin in Lu et al., 1974, Arthricocephalus (Euarthricocephalus) Ju, 1983 are lumped into eight species. The speciation trend of Arthricocephalus and Arthricocephalites is demonstrated based on their stratigraphic occurrences. It not only enhances the resolution of the biostatigraphic zonation in the uppermost Lower Cambrian, but also represents a potential candidate to define the Duyunian stage. The base of the stage is suggested at the first appearance datum (FAD) of Arthricocephalus chauveaui Bergeron, 1899 within the evolutionary lineage from Ar. jiangkouensis Yin in Yin & Li,1978 to Ar. chauveaui in a global scale.     

寒武纪叶足动物与现生有爪类的亲缘关系再讨论

目的 对位于中国云南省东部的早寒武世澄江化石库保存的软躯体构造的叶足动物化石进行系统研究,探究叶足动物这一灭绝类群与现生有爪类的亲缘关系.方法 将叶足动物化石与现生有爪类进行形态对比分析,详细讨论它们之间可能的近裔特征,从生物演化角度系统探究两者之间的亲缘关系.结果 叶足动物与现生有爪类亲缘关系相对较远.结论 现生有爪类极有可能是叶足动物演化过程中的一个侧支.     

Eocrinoid echinoderms from the Lower Cambrian Guanshan Fauna in Wuding, Yunnan, China

This is a brief report of a new occurrence of eocrinoids from the Early Cambrian Wulongqing Formation in Yunnan, China. The eocrinoids from the Guanshan fauna are among the earliest known eocrinoids. Different from many other Early and Middle Cambrian eocrinoids, the Guanshan eocrinoids are char-acterized by the absence of sutural pores and epispires, the long and spiral brachioles, the extremely long stalk, and the ratio of the length of the stalk versus that of the calyx. The discovery of the eocri-noids from the Guanshan fauna not only provides new information to the investigation of the early evolution of this animal group, but also shed new light on the occurrence and migration of early eocrinoids.