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Weber B.,Free University of Berlin | Hu S.,Yunnan Institute of Geological science | Steiner M.,Free University of Berlin | Zhao F.,CAS Nanjing Institute of Geology and Palaeontology
Bulletin of Geosciences | Year: 2012

A diverse and well-preserved ichnofauna from the Cambrian (Stage 4: Canglangpuan) Wulongqing Formation (Kunming area, Yunnan Province) is reported here for the first time in detail. Early Cambrian ichnoassemblages are common and have been described from many localities worldwide; however, they are rarely associated with a significant body fossil record that enables both a well-defined biostratigraphic calibration of the related ichnofauna and a direct comparison with the possibly related trace originators, as is the case with the Wulongqing Formation. The ichnofauna consists of various simple bedding-plane-parallel and sub-horizontal traces of Planolites-type as well as of branching, treptichnid-type burrows, Phycodes- and Teichichnus-type "spreiten", star-shaped trace structures associated with short, central and vertical burrow structures, and arthropod traces of the Diplichnites-type. Large, star-shaped trace fossils belonging to a new ichnotaxon (Guanshanichnus glockerichnoides igen. et isp. nov.) are reported from the Yangtze Platform for the first time and represent the hitherto oldest (equivalent to Botoman regional stage of Siberia) known evidence of this trace type and further global-scale evidence of this trace type from a shallow-water environment. Arthropod traces appear in less abundance in the middle part of the formation. Several arthropod traces display a significant, V-shaped, paired arrangement of scratch marks onthe bedding plane; their morphology and size correspond with co-occurring trilobite taxa from the Wulongqing Formation, probably indicating the preservation of trilobite resting traces. The Shitangshan trace fauna as part of the Guanshan Fauna provides new insights into the palaeoecology and taphonomy of Chengjiang-type fossil Lagerstätten.

Hu S.,Yunnan Institute of Geological science | Steiner M.,Free University of Berlin | Zhu M.,CAS Nanjing Institute of Geology and Palaeontology | Luo H.,Yunnan Institute of Geological science | And 4 more authors.
Bulletin of Geosciences | Year: 2012

A new priapulid assemblage, including 4 palaeoscolecidans and one corynetiid, is reported from the Guanshan fossil Lagerstätte (Cambrian Stage 4, Series 2) from East Yunnan, SW China. Three palaeoscolecidan new species, namely Yunnanoscolex magnus gen. et sp. nov., Wudingscolex sapushanensis gen. et sp. nov., Paramaotianshania zijunia gen. et sp. nov., and a new corynetiid species, Corynetis fortis sp. nov. are described. The lifestyles of these animals and their ecological significance are discussed. The occurrence of abundant and diverse priapulids from both the Chengjiang and Guanshan fossil Lagerstätten in East Yunnan indicates a possible radiation centre of this animal group on the soft-substratum shelf of the western part of the Yangtze Platform.

Hu S.,Yunnan Institute of Geological science | Zhang Z.,Northwest University, China | Holmer L.E.,Uppsala University | Skovsted C.B.,Uppsala University
Acta Palaeontologica Polonica | Year: 2010

Linguliform brachiopods were important components of early Cambrian benthic communities. However, exceptionally preserved soft parts in Cambrian linguliform brachiopods are extremely sparse, and the most important findings are from the early Cambrian Chengjiang Konservat Lagersttte of Kunming, southern China. Here we describe the first record of preserved soft-part anatomy in a linguliform brachiopod from the early Cambrian Guanshan fauna (Wulongqing Formation, Palaeolenus Zone); a unit which is considerably younger than the Chengjiang fauna. The well preserved soft anatomy include linguliform pedicles, marginal setae and, in a few cases, an intact lophophore imprint. The pedicle has pronounced surface annulations, with its proximal-most part enclosing the apex of the ventral pseudointerarea; the pedicle is up to 51 mm long, corresponding to more than 4 times the sagittal length of the shell, and 12% of the maximum valve width. In details of their preservation, these new fossils exhibit striking similarities with the linguliforms from the older Chengjiang fauna, and all specimens are preserved in a compressed state as flattened impressions. The new linguliform has an elongate oval to subtriangular shell and an elongate triangular ventral pseudointerarea; the pedicle emerged from an apical foramen through a poorly preserved internal pedicle tube. The new linguliform is most similar to the mostly organic-shelled siphonotretoid-like brachiopod Acanthotretella spinosa, recently described from the classic middle Cambrian Burgess Shale Konservat Lagersttte, British Columbia, Canada. The new species Acanthotretella decaius sp. nov. is described; it differs from A. spinosa in having a slightly thicker pedicle, and a larger and more rigid, probably partly mineralised shell, indicating that the mostly organic shell of A. spinosa may represent a secondary reduction of shell mineralisation. However, the spine-like setae of the new species are unfortunately poorly preserved only at the margin of the shell, but the new species is referred tentatively to the Superfamily Siphonotretoidea. The occurrence of A. decaius in the Guanshan fauna is the first lower Cambrian (Series 2, early Stage 4) record of both Acanthotretella and siphonotretoids, and it represents the first description of a lophophore and digestive tract from the siphonotretoid lineage.

Wang X.,National Research Center for Geoanalysis | Hu S.,Yunnan Institute of Geological science | Gan L.,National Research Center for Geoanalysis
Terra Nova | Year: 2010

The emergence of the Metazoa can be dated back to the Neoproterozoic Era which comprises the Cryogenian Period during which two major glaciations occurred, the Sturtian and the Varanger-Marinoan. At that time, the phylum Porifera (sponges) evolved as the first animals and developed a hard skeleton. The two classes of siliceous sponges, the Hexactinellida and the Demospongiae, are already provided with the major genetic repertoire and gene regulatory networks that also exist in modern multicellular animals. Besides these metazoan innovations, the siliceous sponges display one autapomorphic character, silicatein, an enzyme which mediates bio-silica formation. Well preserved siliceous sponge fossils have been excavated from the Cambrian Burgess Shale- and Chengjiang deposits. It is concluded that it was the hard skeleton of the siliceous sponges that contributed to the successful evolution and survival of the Porifera during the last 500 Ma. © 2009 Blackwell Publishing Ltd.

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