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Saetaspongia so far cannot be confidently assigned to any class-level crown group. Clarifying its phylogenetic position requires new information provided by more detailed studies of previously described and/or new material. Some sponge fossils with the typical skeletal architecture of Saetaspongia have recently been recognized in the Cambrian (Stage 4) Balang Biota of Guizhou, China, including S. jianhensis new species and S. cf. S. densa. The new taxon is characterized by the following features: spicules are fine monaxons and are inclined to be loosely to densely arranged into plumose arrays; skeleton is composed primarily of one major plumose bundle, with an uncertain number (perhaps two) of small plumose arrays; and primary skeleton is occasionally interspersed with some irregularly oriented individual spicules. An additional specimen consisting of large monaxons, with plumose structures and overlying irregular coarse monaxons, closely fits the description and illustrations of previously described S. cf. S. densa. By combining information from previous studies and the present research, fossil evidence indicates that the plumose architecture is a critical feature diagnostic of Saetaspongia and that there are no hexactine-based spicules in this genus. The new material from the Balang Biota further supports the notion that Saetaspongia has a protomonaxonid rather than a hexactinellid affinity. Fossil evidence suggests that Saetaspongia had a wide biogeographic distribution during the early Cambrian and the stratigraphic distribution of this genus extends up to Stage 4. UUID: http://zoobank.org/e9ca5e4a-134c-4daa-9266-19085e32614f. [ABSTRACT FROM AUTHOR]

It is important to understand moulting behaviours in trilobites through different growth stages. Most studies have focused on patterns of moulting in trilobites based on a few exuviae. The present study is based on 177 disarticulated specimens of Arthricocephalites xinzhaiheensis from the Balang Formation (Cambrian Series 2, Stage 4, Guizhou Province, South China). The abundance of disarticulated assemblages allows the distinction between carcasses and exuviae to be made with confidence and enables a detailed exploration of moulting behaviours. About 96.6% of exuviae of both meraspides and holaspides of Ar. xinzhaiheensis show a disarticulated cranidium characterizing Henningsmoen's configuration. The trilobites commonly used the cephalic sutures and cephalothoracic joint for moulting, involving lateral rotation or inversion of the cranidium to create a wide exuvial gape. Only one specimen displays the Somersault configuration characterized by an overturned lower cephalic unit and the data also show that trilobites employing the cephalic sutures to create an anterior exuvial gape are rare in holaspides. Though some specimens are similar to Salter's configuration with an inverted cephalon with respect to the thoracopygon, the specimens show closed cephalic sutures and thus dissociated or inverted cephala are likely to represent disturbed carcasses. Several other species of oryctocephalid trilobites display Henningsmoen's configuration indicating that exuviation by disarticulated cranidium to enlarge the exuvial gape was prevalent in the family from Cambrian Series 2 Stage 4 to the succeeding Wuliuan Stage of the Miaolingian Series. [ABSTRACT FROM AUTHOR]

The Cambrian (Stage 4) Balang Fauna is a significant Burgess Shale-type biota from South China. The sponge animals are one of the major components of the fauna and are dominated by protomonaxonids. Sponge fossils, having the diagnostic skeletal architecture and bowl-shaped body form of Hamptonia Walcott 1920, are described here as H. jianhensis sp. nov. Its skeleton is characterized by the large spicules that are substantially larger than the dominant fine ones. Although H. jianhensis sp. nov. generally shows a radiating spicule array, some spicules are semi-regularly or irregularly arranged, especially the coarse ones. The previous and present studies suggest Hamptonia has a relatively long stratigraphic range (early Cambrian to Middle Ordovician) and an effectively cosmopolitan distribution during the Early Palaeozoic. The new taxon can provide additional biogeographical informations for Hamptonia sponges. [ABSTRACT FROM AUTHOR]

The gogiid eocrinoid Guizhoueocrinus yui is the most abundant member of the marine benthos in the Balang Fauna (Cambrian Series 2, Stage 4) of Guizhou, China. To date, little attention has been paid to the morphological development of the thecal plates. Here, based on 120 specimens, we describe the morphological development of the primary large thecal plate in the widest part of the theca (WPT). These results demonstrate that the primary large thecal plates in different ontogenetic stages exhibit a unique trajectory within a space defined by size and shape. As the individual grows, the centroid size of the plates shows a continuous changing process. Moreover, the shape of the plate alters during the ontogeny: initially polygonal to oval, then develop a more sprocket-like shape. These results provide statistically supported differences among three pre-defined ontogenetic stages. However, the thecal plates show a gradual growth in seven divided sub-stages. These morphological changes prove that the margins of the primary large thecal plate in the WPT underwent a process of resorption and redeposition to produce more sutural pores. This study demonstrates that newborn sutural pores may help organism to get more oxygen for supporting individuals' life activities. [ABSTRACT FROM AUTHOR]

The morphology and trunk development of the trilobite Arthricocephalus chauveaui described herein are based on 216 articulated specimens collected from the Lazizhai section of the Balang Formation (Stage 4, Series 2 of the Cambrian) in Jianhe County, Guizhou Province, South China. The new specimens exhibit a relatively complete ontogenetic sequence ranging from the protaspid to holaspid periods and reveal more morphological changes of the species in detail. For example, from degrees 0 to 4, the facial sutures are proparian and then gradually move backward from degree 5, until in the holaspid period, the suture becomes gonatoparian. Based on both linear measurements, we investigate here the morphological variation of some cranial traits throughout ontogeny. Our results demonstrate that the allometric growth pattern shows continuous variations, some of which are related to trunk development. By exploring the trunk segmentation in A.chauveaui, the developmental mode shows that somitogenesis and tagmosis may have developed independently at each meraspid degree beyond degree 0. The holaspid period is consistent with the beginning of the epimorphic phase. [ABSTRACT FROM AUTHOR]

New Cambrian sponge fossils can generate alternative interpretations of the phylogenetic and biogeographical history of early sponges. Recently, many sponge fossils have been discovered from the Stage 4 Balang Fauna of Guizhou, China; these sponges are dominated by protomonaxonids, some of which can provide reliable evidence for interpreting the above-mentioned history. The sponge fossils, having the basic skeletal architecture of leptomitids, are recognized here as Jianhella obconica nov. gen., nov. sp., and Leptomitus teretiusculus Chen, Hou et Lu, 1989. The new taxon has a large obconical shape; it is characterized by a dominantly longitudinal skeleton consisting of isolated longitudinal and oblique monaxons, and apparently lacks transverse spicules. The obconical body form and unique skeleton show that Jianhella nov. gen. clearly differs from previously described leptomitids and suggest that it may represent an intermediate morphology between leptomitids and basal protomonaxonids. The occurrence of Jianhella nov. gen. from a single deposit and its absence elsewhere may indicate that it was a monospecific, endemic genus, but may also suggest that it was a rare genus, so far exemplified by its occurrence in a single site with very few specimens. Additional specimens with an elongated tubular shape and a skeleton consisting of bundled longitudinal monaxons and isolated transverse spicules closely fit the description and illustrations of Leptomitus teretiusculus from the Cambrian biotas of South China. According to the spicule morphology, the degree of spicule bundling and the skeletal architecture, there likely exists a deep node separating Jianhella nov. gen. from the earlier ancestral members of Leptomitus. Fossil evidence, together with previous studies, confirms that Leptomitus generally had a relatively long stratigraphic range (Cambrian Stage 3 to Drumian) and had an effectively cosmopolitan distribution during the early and middle Cambrian. [ABSTRACT FROM AUTHOR]

Tuzoia is a large, bivalved Cambrian arthropod having a widespread distribution in shallow‐shelf to deeper marine Lagerstätten; stratigraphically it ranges from Cambrian Series 2 through the Miaolingian Series. In the present study, three species are recognized from relatively deep‐water deposits of the Balang Formation (Cambrian Stage 4) of Guizhou, South China: Tuzoia sinensis Pan, 1957, T. bispinosa Yuan et Zhao, 1999 and T. lazizhaiensis sp. nov. The new species is unique in having 6–10 small marginal spines on the dorsal margin, an inflated anterior margin with three short, closely spaced marginal spines. These remains, which usually occur as disarticulated valves, are inferred to be parautochthonous. One new specimen of T. lazizhaiensis shows a stalked eye and antenna. New Tuzoia material from the Kaili Biota (Cambrian: Wuliuan Stage) of Guizhou, and from the Guanshan Biota (Cambrian Stage 4) of Yunnan, China, provide additional comparative information about the genus. Some new specimens of T. bispinosa from the Kaili Biota provide information on valve morphology and palaeoecology. One specimen of T. sinensis from the Guanshan Biota provides information on the appendages, and one specimen of T. tylodesa, from the Guanshan Biota adds provides information on the trunk and appendages. [ABSTRACT FROM AUTHOR]

The Wuliu-Zengjiayan section in Jianhe County, Guizhou Province, China has been suggested as a potential Global Stratotype Section and Point (GSSP) for the defined base of Cambrian Series 3. A molecular organic geochemical study on the Cambrian Series 2-Series 3 boundary interval was carried out to reveal the biotic and environmental change during this transition. The hydrocarbons extracted from the Kaili Formation were proved to be indigenous. The various geochemical proxies such as biomarker parameter, δC, atomic H/C value of kerogen, and TOC content, co-vary along with the sedimentary column, and show a quick and significant change just across the Cambrian Series 2-Series 3 boundary. The less abundance of isoprenoid hydrocarbons, the relative enrichment of midchain monomethyl branched alkanes ( mmb-alkanes), the relatively negative value of δC, and the higher TOC contents may suggest that the upper Cambrian Series 2 was deposited in a relatively reducing environment with a higher organic input from cyanobacteria-predominated benthic microbial mats. On the other hand, the relative enrichment of isoprenoid hydrocarbons, the less abundance of mmb-alkanes, the relatively positive value of δC, the lower TOC contents, and the lower atomic H/C values of kerogen are combined to indicate an enhanced phytoplankton production and an increased oxygen content and nutrients in the ocean during the early Cambrian Series 3, which could have benefited the explosion of the Kaili Biota. The Wuliu-Zengjiayan section may provide a typical case to understand the co-variation of marine microbe, animal, and environment. [ABSTRACT FROM AUTHOR]

In order to help facilitate stratigraphic correlation between south China and Siberia, trilobite zones of Guizhou, China, and the Molodo River area, Siberia, need to be better coordinated. The Wuliu-Zengjiayan section is a strong candidate for the Global Standard Stratotype Section and Point for Cambrian Stage 5, and the Molodo River section provides important supplemental information that helps expand the precision of correlation on a global scale. The Kaili Formation in the Wuliu-Zengjiayan section contains three trilobite zones over an interval of 214.20 m. We propose that theOvatoryctocara granulataZone, as used in Siberia, replace theOvatoryctocaraZone. Equivalent strata in Guizhou extend more than 150 m stratigraphically, from theProtoryctocephalus wuxunensisZone to theBathynotus kueichouensis–O.cf. O. granulataAssemblage Zone. We also propose that the traditionalKounamkitesZone be supplemented or replaced by theOryctocephalus reticulatusZone, which outside Siberia containsOryctocephalus indicus. [ABSTRACT FROM AUTHOR]

Abundant cryptospore-like microfossils have been collected from a sample of the 'Middle' Cambrian Log Cabin Member of the Pioche Shale in eastern Nevada, USA. Compared with organic-walled microfossils obtained from the Cambrian Kaili Formation in eastern Guizhou Province, China, some specimens of leiosphers may be inferred to be similar cryptospore-like microfossils. The new fossil record would be the oldest known specimens of cryptospore-like microfossils during the Cambrian Period. [ABSTRACT FROM AUTHOR]

Bivalved arthropods are very important elements in Mid-Cambrian Kaili Biota. Three genera, Alicaris, Pseudoarctolepis, and Forfexicaris, are herein recorded for the first time, including three new species: Alicaris kailiensis sp. nov., Forfexicaris reticulata sp. nov., and Pseudoarctolepis semicircularis sp. nov., of which Alicaris kailiensis sp. nov. could be assigned to crustaceomorphs; the other two forms are grouped as proschizoramians. These forms provide important information about the distribution and species diversity of a poorly-known element of Cambrian fauna, and also bridge the biotic evolutionary gap between Early Cambrian Chengjiang Biota in Southwest China and Mid-Cambrian burgess shale biota in North America. [ABSTRACT FROM AUTHOR]

Focuses on the discovery of fossil assemblage of early Cambrian fauna in Kaili City, Guizhou Province, China. Topographic description of the area; Characteristics of Cambrian fauna; Phyla of fossil specimens collected from the fauna.

Reports on the discovery of a Miaohe-type Biota from the neoproterozoic doushantuo formation in Jiangkou County, Guizhou Sheng Province, China. Discussion on the discovery of the megascopic algal fossil assemblage; Place on the preservation of Miaohe Biota fossils; Identification of a new fossil assemblage similar to Miaohe Biota on April 2004.

The First Appearance Datum (FAD) of the oryctocephalid trilobite Ovatoryctocara granulata Tchernysheva, 1962 is one of the candidates for establishing the base of the Cambrian Series 3, Stage 5. However some records of this taxon in China and elsewhere are doubtful and in need of review. Ovatoryctocara cf. granulata and Ovatoryctocara sp., previously described from the lower part of the Kaili Formation, China are transferred herein to Ovatoryctocara sinensis sp. nov., which shows significant morphological differences with type specimens of O . granulata . All Chinese specimens of Ovatoryctocara are therefore transferred to O. sinensis sp. nov. As consequence, the former trilobite Zone Bathynotus kueichouensis - Ovatoryctocara cf. guanulata is renamed the Bathynotus kueichouensis - Ovatoryctocara sinensis Assemblage Zone. O . granulata from Newfoundland also exhibits large differences in morphology with type specimens of O . granulata from Siberia. It is concluded that O . granulata does not occur in China but is restricted to Siberia and North Greenland. Hence, O . granulata is not suitable for defining the Cambrian Series 2–3 boundary, as previously suggested. [ABSTRACT FROM AUTHOR]

Abstract: Numerous specimens of Guizhoueocrinus yui n gen. et sp. occur in the middle-upper parts of the Lower Cambrian Balang Formation, eastern Guizhou, and are the earliest well preserved gogiids. Mature specimens are larger than most comparable gogiids, thecal plates are very numerous and sutural pores are smaller. Stalk is polyplated, conical and long; brachioles (up to 10) are spirally coiled. The species comprises a significant component of the Balang Fauna. It is distinctly different than Sinoeocrinus lui and Sinoeocrinus globus from the Middle Cambrian Kaili Biota in the adjacent region in Guizhou. This new gogiid expands the geographic range of Lower Cambrian eocrinoids and provides significant new data on gogiid evolution. [Copyright &y& Elsevier]

Abstract: A globally recorded negative carbon isotope excursion characterizes the transition from Cambrian Series 2 to Cambrian Series 3. This transition is also well exposed in sedimentary successions on the Yangtze Platform, and the Wuliu–Zengjiayan section, Guizhou Province, South China has been proposed as a potential Global Stratotype Section and Point (GSSP) for this boundary. Here, we report δ 13Ccarb values for the Jianshan and the Wuliu–Zengjiayan sections. Both sections display a progressive decrease in δ 13C from values around +3‰ upwards in stratigraphy to a pronounced δ 13C minimum with values as low as −6.9‰ at the proposed boundary level, and a return to δ 13C values between 0 and +1‰ in the upper part of the sections. The δ 13C minimum is thought to be caused by a transgressive event, flooding the shelf area with 13C depleted basinal anoxic bottom water. Our δ 13C data are in good agreement with carbon isotope profiles recorded elsewhere. These define the so called ROECE event (Redlichiid–Oleneliid Extinction Carbon Isotope Excursion, cf. Zhu et al., 2006, 2007) and may reflect the perturbation of the global carbon cycle during the Cambrian Series 2 to Cambrian Series 3 transition. [Copyright &y& Elsevier]

Important progrress in research on the Kaili Biota has been made recently. Many interesting components from Chengjiang Biota and Burgess Shale Biota have been discovered, e.g. Microdictyon of lobopodia; Ottoia, Palaeoscolex of worms; Naraoia, Marrella of Trilobitioidea, Mollisonia, anamalocarids and other non-trilobite arthropode; and new sorts of echinoder-mas, macroalage fossils and so on. Recent work on the Kaili Biota has resulted in the following developments: (i) an increase in the number of animal genera, up to more than 100 genera in total, so that the Kaili Biota has become the third most diverse of the Burgess Shale-type Biota after the Burgess Shale and Chensjiang Biotas; and (ii) the most noteworthy fossils in the Kaili Biota are echinoderms, non-trilobite arthropods and soft-bedied medusiform fossils, especially the most diverse echinoderms. The progress provides envidence for the biodiversity of marine organisms presented after the "Cambrian Explosion" and serves as a link between the earlist Cambrian Chengjiang Biota and late early Middle Cambrian Burgess Shale Biota. It is of great significance in the reconstruction of the Cambrian palaeoplate, palaeongeography and in research on taphonomy. [ABSTRACT FROM AUTHOR]