Hostname: page-component-8448b6f56d-sxzjt Total loading time: 0 Render date: 2024-04-19T18:38:25.293Z Has data issue: false hasContentIssue false

Cambrothyra ampulliformis, an unusual coeloscleritophoran from the Lower Cambrian of Shaanxi Province, China

Published online by Cambridge University Press:  14 July 2015

John L. Moore
Affiliation:
1Department of Earth Science, University of California, Santa Barbara, 93106, USA, ,
Susannah M. Porter
Affiliation:
1Department of Earth Science, University of California, Santa Barbara, 93106, USA, ,
Michael Steiner
Affiliation:
2Freie Universität Berlin, Institut für Geologische Wissenschaften, FR Paläontologie, Malteserstraße 74-100, Haus D, 12249 Berlin, Germany,
Guoxiang Li
Affiliation:
3State Key Laboratory of Palaeontology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Academia Sinica, Nanjing 210008, China,

Abstract

Cambrothyra ampulliformis Qian and Zhang, 1983, is a jar- or vase-shaped fossil known from the Lower Cambrian of Shaanxi and Hubei provinces, China. It has been interpreted as a protistan test or cyst or a metazoan sclerite. A large collection of specimens from the Xihaoping Member of the Dengying Formation in southern Shaanxi Province permits its detailed redescription. These fossils are highly variable in shape but this variation is continuous and does not support the current recognition of multiple species for this material. They were originally hollow with a restricted basal foramen and a calcareous wall probably composed of fibrous aragonite. All of these features support the identification of Cambrothyra as sclerites of a coeloscleritophoran, a problematic group of Cambrian scleritome-bearing metazoans. Furthermore, the walls of Cambrothyra sclerites contain numerous pores, a feature shared with other coeloscleritophorans. Cambrothyra resembles chancelloriids in particular due to the shared presence of a verruculose texture around the foramen and the absence of mirror-image pairs of asymmetric sclerites. However, unlike chancelloriids, which have rosette-like compound sclerites, the scleritome of Cambrothyra was dominated by isolated sclerites, with only a few pairs and clusters of sclerites and twin sclerites. Consequently, we hypothesize that Cambrothyra forms a clade with other chancelloriids, but represents a basal lineage that plesiomorphically retained isolated sclerites. The morphology of Cambrothyra sclerites, which shares features with both chancelloriids and halkieriids, thus supports the hypothesis that all coeloscleritophorans form a natural group.

Type
Research Article
Copyright
Copyright © The Paleontological Society 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Álvaro, J. J. and Clausen, S. 2010. Morphology and ultrastructure of epilithic versus cryptic, microbial growth in lower Cambrian phosphorites from the Montagne Noire, France. Geobiology, 8:89100.CrossRefGoogle ScholarPubMed
Bengtson, S. 1992. The cap-shaped Cambrian fossil Maikhanella and the relationship between coeloscleritophorans and molluscs. Lethaia, 25:401420.CrossRefGoogle Scholar
Bengtson, S. 2004. Early skeletal fossils, p. 6777. In Lipps, J. H. and Waggoner, B. M. (eds.), Neoproterozoic–Cambrian Biological Revolutions. Paleontological Society Papers, Vol. 10.Google Scholar
Bengtson, S. 2005. Mineralized skeletons and early animal evolution, p. 101124. In Briggs, D. E. G. (ed.), Evolving Form and Function: Fossils and Development: Proceedings of a Symposium Honoring Adolf Seilacher for his Contributions to Paleontology, in Celebration of his 80th Birthday. Peabody Museum of Natural History, New Haven, Connecticut.Google Scholar
Bengtson, S. and Conway Morris, S. 1984. A comparative study of Lower Cambrian Halkieria and Middle Cambrian Wiwaxia. Lethaia, 17:307329.CrossRefGoogle Scholar
Bengtson, S. and Conway Morris, S. 1992. Early radiation of biomineralizing phyla, p. 447481. In Lipps, J. H. and Signor, P. W. (eds.), Origin and Early Evolution of the Metazoa. Plenum Press, New York.CrossRefGoogle Scholar
Bengtson, S., Conway Morris, S., Cooper, B. J., Jell, P. A., and Runnegar, B. N. 1990. Early Cambrian fossils from South Australia. Memoirs of the Association of Australasian Palaeontologists, Number 9, 364 p.Google Scholar
Bengtson, S., Fedorov, A. B., Missarzhevsky, V. V., Rozanov, A. Yu., Zhegallo, E. A., and Zhuravlev, A. Yu. 1987. Tumulduria incomperta and the case for Tommotian trilobites. Lethaia, 20:361370.CrossRefGoogle Scholar
Bengtson, S. and Hou, X.-G. 2001. The integument of Cambrian chancelloriids. Acta Palaeontologica Polonica, 46:122.Google Scholar
Bengtson, S. and Missarzhevsky, V. V. 1981. Coeloscleritophora—a major group of enigmatic Cambrian metazoans. U.S. Geological Survey Open-File Report, 81-743:1921.Google Scholar
Bokova, A. R. and Vasil'eva, N. I. 1990. Nekotorye novye vidy skeletnykh problematik nizhnego kembriya Olenekskogo Podnyatiya, p. 2833. In Sokolov, B. S. and Zhuravleva, I. T. (eds.), Iskopaemye Problematiki SSSR. Trudy Instituta Geologii i Geofiziki, Akademiya Nauk SSSR, Sibirskoe Otdelenie, Vol. 783.Google Scholar
Botting, J. P. and Butterfield, N. J. 2005. Reconstructing early sponge relationships by using the Burgess Shale fossil Eiffelia globosa, Walcott. Proceedings of the National Academy of Sciences, U.S.A., 102:15541559.CrossRefGoogle ScholarPubMed
Brasier, M. D., Shields, G., Kuleshov, V. N., and Zhegallo, E. A. 1996. Integrated chemo- and biostratigraphic calibration of early animal evolution: Neoproterozoic–Early Cambrian of southwest Mongolia. Geological Magazine, 133:445485.CrossRefGoogle Scholar
Butterfield, N. J. 1990. A reassessment of the enigmatic Burgess Shale fossil Wiwaxia corrugata (Matthew) and its relationship to the polychaete Canadia spinosa Walcott. Paleobiology, 16:287303.CrossRefGoogle Scholar
Butterfield, N. J. 2003. Exceptional fossil preservation and the Cambrian explosion. Integrative and Comparative Biology, 43:166177.CrossRefGoogle ScholarPubMed
Butterfield, N. J. and Nicholas, C. J. 1996. Burgess Shale-type preservation of both non-mineralizing and ‘shelly’ Cambrian organisms from the Mackenzie Mountains, northwestern Canada. Journal of Paleontology, 70:893899.CrossRefGoogle Scholar
Cao, F. 1996. Vase-shaped microfossil horizons in Yangtze Platform of China. Acta Geoscientia Sinica, 17(Special Issue):210216.Google Scholar
Cao, F. 1998. [Study on the vase-shaped microfossils in China.] Acta Micropalaeontologica Sinica, 15:404416. (In Chinese).Google Scholar
Cao, F. 2000. [On the vase-shaped microfossils.] Acta Micropalaeontologica Sinica, 17:327332. (In Chinese).Google Scholar
Cao, F., Duan, C.-H., and Zhang, L.-Y. 1995. [Discovery of Meishucunian vase-shaped microfossils in Ningqiang, Shaanxi and its significances.] Geological Review, 41:355362. (In Chinese).Google Scholar
Caron, J.-B., Scheltema, A., Schander, C., and Rudkin, D. 2006. A soft-bodied mollusc with radula from the Middle Cambrian Burgess Shale. Nature, 442:159163.CrossRefGoogle ScholarPubMed
Chen, M.-E. 1979. [Some skeletal fossils from the phosphatic sequence, early Lower Cambrian, south China.] Scientia Geologica Sinica, 1979:187189. (In Chinese).Google Scholar
Clausen, S. and Álvaro, J. J. 2006. Skeletonized microfossils from the Lower–Middle Cambrian transition of the Cantabrian Mountains, northern Spain. Acta Palaeontologica Polonica, 51:223238.Google Scholar
Conway Morris, S. 1985. The Middle Cambrian metazoan Wiwaxia corrugata (Matthew) from the Burgess Shale and Ogygopsis Shale, British Columbia, Canada. Philosophical Transactions of the Royal Society of London B, 307:507582.Google Scholar
Conway Morris, S. and Caron, J.-B. 2007. Halwaxiids and the early evolution of the lophotrochozoans. Science, 315:12551258.CrossRefGoogle Scholar
Conway Morris, S. and Chapman, A. J. 1996. Lower Cambrian coeloscleritophorans (Ninella, Siphogonuchites) from Xinjiang and Shaanxi, China. Geological Magazine, 133:3351.CrossRefGoogle Scholar
Conway Morris, S. and Chapman, A. J. 1997. Lower Cambrian halkieriids and other coeloscleritophorans from Aksu-Wushi, Xinjiang, China. Journal of Paleontology, 71:622.CrossRefGoogle Scholar
Conway Morris, S. and Chen, M.-E. 1991. Cambroclaves and paracarinachitids, early skeletal problematica from the Lower Cambrian of South China. Palaeontology, 34:357397.Google Scholar
Conway Morris, S. and Peel, J. S. 1995. Articulated halkieriids from the Lower Cambrian of North Greenland and their role in early protostome evolution. Philosophical Transactions of the Royal Society of London B, 347:305358.Google Scholar
Demidenko, Yu. E. 2000. Novye sklerity khantselloriid iz nizhnego kembriya Yuzhnoy Avstralii. Paleontologicheskiy Zhurnal, 2000(4):2024.Google Scholar
Demidenko, Yu. E. and Parkhaev, P. Yu. 2006. Taksonomicheskoe raznoobrazie rannekembriyskoy melkorakovinnoy fauny Kitaya, p. 492505. In Rozhnov, S. V. (ed.), Evolyutsiya Biosfery i Bioraznoobraziya. K 70-letiyuRozanova, A. Yu.KMK, Moscow.Google Scholar
Ding, L.-F., Qin, H.-B., and Li, Y. 1990. [Study on the boundary between Sinian and Cambrian in the south of Shaanxi Province, China.] Professional Papers of Stratigraphy and Palaeontology, 23:96130. (In Chinese).Google Scholar
Ding, L.-F., Zhang, L.-Y., Li, Y., and Dong, J.-S. 1992. [The Study of the Late Sinian–Early Cambrian Biota from the Northern Margin of Yangtze Platform]. Scientific and Technical Documents Publishing House, Beijing, 156 p. (In Chinese).Google Scholar
Doré, F. and Reid, R. E. 1965. Allonnia tripodophora nov. gen., nov. sp., nouvelle éponge du Cambrien inférieur de Carteret (Manche). Compte Rendu Sommaire des Séances de la Société Géologique de France, 1965:2021.Google Scholar
Duan, C.-H. 1984. [Small shelly fossils from the Lower Cambrian Xihaoping Formation in the Shennongjia District, Hubei Province—hyoliths and fossil skeletons of unknown affinities.] Bulletin of the Tianjin Institute of Geology and Mineral Resources, Chinese Academy of Geological Sciences, 7:143188. (In Chinese).Google Scholar
Duan, C.-H. 1986. [The earliest Cambrian vase-shaped microfossils of Fangxian County, Hubei Province.] Bulletin of the Tianjin Institute of Geology and Mineral Resources, Chinese Academy of Geological Sciences, 13:87110. (In Chinese).Google Scholar
Duan, C.-H. and Cao, F. 1989. [A new discovery of Precambrian vase-shaped microfossils in the Eastern Yangtze Gorges of Hubei Province.] Bulletin of the Tianjin Institute of Geology and Mineral Resources, Chinese Academy of Geological Sciences, 21:129147. (In Chinese).Google Scholar
Duan, C.-H., Cao, F., and Zhang, L.-Y. 1993. [Vase-shaped microfossils from top of Töngying Formation in Xixiang, Shaanxi.] Acta Micropalaeontologica Sinica, 10:397408. (In Chinese).Google Scholar
Esakova, N. V. and Zhegallo, E. A. 1996. Biostratigrafiya i fauna nizhnego kembriya Mongolii. Trudy Sovmestnaya Rossiysko-Mongol'skaya Paleontologicheskaya Ekspeditsiya, Vol. 46, 216 p.Google Scholar
Feng, W.-M., Mu, X.-N., Sun, W.-G., and Qian, Y. 2002. Microstructure of Early Cambrian Ramenta from China. Alcheringa, 26:917.Google Scholar
Feng, W.-M. and Sun, W.-G. 2003. Phosphate replicated and replaced microstructure of molluscan shells from the earliest Cambrian of China. Acta Palaeontologica Polonica, 48:2130.Google Scholar
Feng, W.-M. and Sun, W.-G. 2006. Monoplacophoran Igorella-type pore-channel structures from the Lower Cambrian in China. Materials Science and Engineering C, 26:699702.CrossRefGoogle Scholar
Fernández Remolar, D. C. 2001a. Chancelloridae del Ovetiense Inferior de la Sierra de Córdoba, España. Revista Española de Paleontología, 16:3961.Google Scholar
Fernández Remolar, D.C. 2001b. Latest Neoproterozoic to Middle Cambrian body fossil record in Spain (exclusive of trilobites and archaeocyaths) and their stratigraphic significance. GFF, 123:7380.CrossRefGoogle Scholar
Geng, L.-Y. and Zhang, S.-B. 1987. Early Cambrian problematic fossils from Fangxian, Hubei, China, p. 523536. In Stratigraphy and Palaeontology of Systemic Boundaries in China: Precambrian–Cambrian Boundary, Vol. 1. Nanjing University Publishing House, Nanjing.Google Scholar
Gravestock, D. I., Alexander, E. M., Demidenko, Yu. E., Esakova, N. V., Holmer, L. E., Jago, J. B., Lin, T.-R., Melnikova, L. M., Parkhaev, P. Yu., Rozanov, A. Yu., Ushatinskaya, G. T., Zang, W.-L., Zhegallo, E. A., and Zhuravlev, A. Yu. 2001. The Cambrian biostratigraphy of the Stansbury Basin, South Australia. Transactions of the Palaeontological Institute, Russian Academy of Sciences, Vol. 282, 344 p.Google Scholar
Gray, M.E. 1850. Figures of Molluscous Animals, Selected from Various Authors, Vol. 4. Longman, Brown, Green and Longmans, London, 219 p.Google Scholar
He, Y.-X. and Yang, X.-H. 1986. [Early Cambrian coelenterates from Nanjiang, Sichuan.] Bulletin of the Chengdu Institute of Geology and Mineral Resources, Chinese Academy of Geological Sciences, 7:3148. (In Chinese).Google Scholar
Hinz, I. 1987. The Lower Cambrian microfauna of Comley and Rushton, Shropshire/England. Palaeontographica Abt. A, 198:41100.Google Scholar
Hirschler, A., Lucas, J., and Hubert, J.-C. 1990. Apatite genesis: A biologically induced or biologically controlled mineral formation process? Geomicrobiology Journal, 8:4756.CrossRefGoogle Scholar
Hua, H., Chen, Z., and Yuan, X.-L. 2007. The advent of mineralized skeletons in Neoproterozoic Metazoa—new fossil evidence from the Gaojiashan fauna. Geological Journal, 42:263279.Google Scholar
Hua, H., Zhang, L.-Y., and Chen, Z. 2003. Microbially mediated phosphatization in the late Sinian skeletal fossils, southern Shaanxi. Acta Palaeontologica Sinica, 42:189199.Google Scholar
Janussen, D., Steiner, M., and Zhu, M.-Y. 2002. New well-preserved scleritomes of Chancelloridae from the Early Cambrian Yuanshan Formation (Chengjiang, China) and the Middle Cambrian Wheeler Shale (Utah, USA) and paleobiological implications. Journal of Paleontology, 76:596606.2.0.CO;2>CrossRefGoogle Scholar
Jell, P. A. 1981. Thambetolepis delicata gen. et sp. nov., an enigmatic fossil from the Early Cambrian of South Australia. Alcheringa, 5:8593.CrossRefGoogle Scholar
Kerber, M. 1988. Mikrofossilien aus unterkambrischen Gesteinen der Montagne Noire, Frankreich. Palaeontographica Abt. A, 202:127203.Google Scholar
Khomentovsky, V. V. and Karlova, G. A. 1993. Biostratigraphy of the Vendian-Cambrian beds and the lower Cambrian boundary in Siberia. Geological Magazine, 130:2945.CrossRefGoogle Scholar
Kouchinsky, A. 2000a. Shell microstructures in Early Cambrian molluscs. Acta Palaeontologica Polonica, 45:119150.Google Scholar
Kouchinsky, A. V. 2000b. Skeletal microstructures of hyoliths from the Early Cambrian of Siberia. Alcheringa, 24:6581.CrossRefGoogle Scholar
Kouchinsky, A. and Bengtson, S. 2002. The tube wall of Cambrian anabaritids. Acta Palaeontologica Polonica, 47:431444.Google Scholar
Lee, H.-Y., Lee, K.-J., and Yi, M.-S. 1993. Revision and addition on the Cambrian microfauna from the Kurangni area, Mungyeong-gun, Gyeongsanbuk-do, South Korea. Journal of the Paleontological Society of Korea, 9:6276.Google Scholar
Lee, H.-Y., Roh, D.-S., Lee, B.-S., and Yi, M.-S. 1992. Small shelly fossils and conodonts from the Myobong and Daegi formations in Baegunsan Syncline, Yeongweol-Jeongseon area, Kangweon-do. Journal of the Paleontological Society of Korea, 8:140163.Google Scholar
Li, G.-X. 1997. Early Cambrian phosphate-replicated endolithic algae from Emei, Sichuan, SW China. Bulletin of National Museum of Natural Science, 10:193216.Google Scholar
Li, G.-X. 1999. [Early Cambrian chancelloriids from Emei, Sichuan Province, SW China.] Acta Palaeontologica Sinica, 38:238247. (In Chinese).Google Scholar
Li, G.-X. 2004. [Early Cambrian hyolithelminths—Torellella bisulcata sp. nov. from Zhenba, southern Shaanxi]. Acta Palaeontologica Sinica, 43:571578. (In Chinese).Google Scholar
Li, G.-X. and Holmer, L. E. 2004. Early Cambrian lingulate brachiopods from the Shaanxi Province, China. GFF, 126:193211.CrossRefGoogle Scholar
Li, G.-X., Zhu, M.-Y., Steiner, M., and Qian, Y. 2004. Skeletal faunas from the Qiongzhusian of southern Shaanxi: Biodiversity and lithofacies-biofacies links in the Lower Cambrian carbonate settings. Progress in Natural Science, 14:9196.CrossRefGoogle Scholar
Li, Y., Guo, J.-F., Zhang, X.-L., Zhang, W.-Q., Liu, Y.-H., Yang, W.-X., Li, Y.-Y., Liu, L.-Q., and Shu, D.-G. 2008. Vase-shaped microfossils from the Ediacaran Weng'an biota, Guizhou, South China. Gondwana Research, 14:263268.CrossRefGoogle Scholar
Li, Y., Qin, H.-B., and Ding, L.-F. 1993. [Early sponge spicules of the Early Cambrian era from the north margin of the Yangtze Platform.] Journal of Xi'an College of Geology, 15(2):3139. (In Chinese).Google Scholar
Lucas, J. and Prévôt, L. E. 1991. Phosphates and fossil preservation, p. 389409. In Allison, P. A. and Briggs, D. E. G. (eds.), Taphonomy: Releasing the Data Locked in the Fossil Record. Plenum Press, New York.CrossRefGoogle Scholar
Luo, H.-L., Jiang, Z.-W., Wu, X.-C., Song, X.-L., Ouyang, L., et al. 1982. [The Sinian-Cambrian Boundary in Eastern Yunnan, China.] People's Publishing House, Yunnan, 267 p. (In Chinese with English abstract).Google Scholar
Malakhova, N. P. 1975. Foraminifery nizhnego vize vostochnogo sklona Yuzhnogo Urala, p. 570. In Malakhova, N. P. and Chuvashov, B. I. (eds.), Foraminifery i Stratigrafiya Rannego Vize Urala. Trudy Instituta Geologii i Geokhimii, Akademiya Nauk SSSR, Ural'skiy Nauchnyy Tsentr, Vol. 112.Google Scholar
Mambetov, A. M. and Repina, L. N. 1979. Nizhniy kembriy Talasskogo Ala-Too i ego korrelyatsiya s razrezami Malogo Karatau i Sibirskoy Platformy, p. 98138. In Zhuravleva, I. T. and Meshkova, N. P. (eds.), Biostratigrafiya i Paleontologiya Nizhnego Kembriya Sibiri. Trudy Instituta Geologii i Geofiziki, Akademiya Nauk SSSR, Sibirskoe Otdelenie, Vol. 406.Google Scholar
Mehl, D. 1996. Organization and microstructure of the chancelloriid skeleton: Implications for the biomineralization of the Chancelloriidae. Bulletin de l'Institut Océanographique de Monaco, No. Spécial 14(4):377385.Google Scholar
Meshkova, N. P. 1969. K voprosy o paleontologicheskoy kharakteristike nizhnekembriyskikh otlozheniy Sibirskoy Platformy, p. 158174. In Zhuravleva, I. T. (ed.), Biostratigrafiya i Paleontologiya Nizhnego Kembriya Sibiri i Dal'nego Vostoka. Nauka, Moscow.Google Scholar
Missarzhevsky, V. V. and Mambetov, A. M. 1981. Stratigrafiya i fauna pogranichnykh sloev kembriya i dokembriya Malogo Karatau. Trudy, Ordena Trudovogo Krasnogo Znameni Geologicheskiy Institut, Akademiya Nauk SSSR, Vol. 326, 92 p.Google Scholar
Parkhaev, P. Yu. 2006. O rode Auricullina Vassiljeva, 1998 i rakovinnykh porakh kembriyskikh gel'tsionelloidnykh mollyuskov. Paleontologicheskiy Zhurnal, 2006(1):2032.Google Scholar
Ponder, W. F., Parkhaev, P. Yu., and Beechey, D. L. 2007. A remarkable similarity in scaly shell structure in Early Cambrian univalved limpets (Monoplacophora; Maikhanellidae) and a Recent fissurellid limpet (Gastropoda: Vetigastropoda) with a review of Maikhanellidae. Molluscan Research, 27:129139.CrossRefGoogle Scholar
Porter, S. M. 2004. Halkieriids in Middle Cambrian phosphatic limestones from Australia. Journal of Paleontology, 78:574590.2.0.CO;2>CrossRefGoogle Scholar
Porter, S. M. 2007. Seawater chemistry and early carbonate biomineralization. Science, 316:1302.CrossRefGoogle ScholarPubMed
Porter, S. M. 2008. Skeletal microstructure indicates chancelloriids and halkieriids are closely related. Palaeontology, 51:865879.CrossRefGoogle Scholar
Porter, S. M. 2010. Calcite and aragonite seas and the de novo acquisition of carbonate skeletons. Geobiology, 8:256277.CrossRefGoogle Scholar
Porter, S. M. and Knoll, A. H. 2000. Testate amoebae in the Neoproterozoic Era: Evidence from vase-shaped microfossils in the Chuar Group, Grand Canyon. Paleobiology, 26:360385.2.0.CO;2>CrossRefGoogle Scholar
Porter, S. M., Meisterfeld, R., and Knoll, A. H. 2003. Vase-shaped microfossils from the Neoproterozoic Chuar Group, Grand Canyon: A classification guided by modern testate amoebae. Journal of Paleontology, 77:409429.2.0.CO;2>CrossRefGoogle Scholar
Prévôt, L. and Lucas, J. 1986. Microstructure of apatite-replacing carbonate in synthesized and natural samples. Journal of Sedimentary Petrology, 56:153159.CrossRefGoogle Scholar
Qian, J.-X. and Xiao, B. 1984. [An Early Cambrian small shelly fauna from Aksu-Wushi region, Xinjiang.] Professional Papers of Stratigraphy and Palaeontology, 13:6590. (In Chinese).Google Scholar
Qian, Y. 1989. Stratigraphy and Palaeontology of Systemic Boundaries in China: Precambrian–Cambrian Boundary, Vol. 2: Early Cambrian Small Shelly Fossils of China with Special Reference to the Precambrian–Cambrian Boundary. Nanjing University Publishing House, Nanjing, 342 p.Google Scholar
Qian, Y. and Bengtson, S. 1989. Palaeontology and biostratigraphy of the Early Cambrian Meishucunian Stage in Yunnan Province, South China. Fossils and Strata, Number 24, 156 p.Google Scholar
Qian, Y., Chen, M.-E., He, T.-G., Zhu, M.-Y., Yin, G.-Z., Feng, W.-M., Xu, J.-T., Jiang, Z.-W., Liu, D.-Y., Li, G.-X., Ding, L.-F., Mao, Y.-Q., and Xiao, B. 1999. [Taxonomy and Biostratigraphy of Small Shelly Fossils in China.] Science Press, Beijing, 247 p. (In Chinese).Google Scholar
Qian, Y., Sun, W.-G., He, T.-G., and Chen, M.-E. 2000. [Restudy on “vase-shaped microfossils” from the Lower Cambrian Xihaoping Member in South Shaanxi and West Hubei.] Acta Micropalaeontologica Sinica, 17:317326. (In Chinese).Google Scholar
Qian, Y., Xie, Y.-S., and He, T.-G. 2001. [Hyoliths of the Lower Cambrian Chiungchussuan Stage in South Shaanxi Province.] Acta Palaeontologica Sinica, 40:3143. (In Chinese).Google Scholar
Qian, Y. and Zhang, S.-B. 1983. [Small shelly fossils from the Xihaoping Member of the Tongying Formation in Fangxian County of Hubei Province and their stratigraphical significance.] Acta Palaeontologica Sinica, 22:8294. (In Chinese).Google Scholar
Qian, Y., and Zhang, S.-B. 1985. [On the systematic position of small orthoconic fossils with bulbous initial part from the early Lower Cambrian.] Acta Micropalaeontologica Sinica, 2:113. (In Chinese).Google Scholar
Qin, H.-B. and Ding, L.-F. 1988. [Occurrence of microfossils in the Yangjiagou Member of the Tongying Formation, southern Shaanxi.] Acta Micropalaeontologica Sinica, 5:171178. (In Chinese).Google Scholar
Randell, R. D., Lieberman, B. S., Hasiotis, S. T., and Pope, M. C. 2005. New chancelloriids from the Early Cambrian Sekwi Formation with a comment on chancelloriid affinities. Journal of Paleontology, 79:987996.CrossRefGoogle Scholar
Reindl, S., Salvenmoser, W., and Haszprunar, G. 1995. Fine structural and immunocytochemical investigations of the caeca of Argyrotheca cordata and Argyrotheca cuneata (Brachiopoda, Terebratulida, Terebratellacea). Journal of Submicroscopic Cytology and Pathology, 27:543556.Google Scholar
Reindl, S., Salvenmoser, W., and Haszprunar, G. 1997. Fine structural and immunocytochemical studies on the eyeless aesthetes of Leptochiton algesirensis, with comparison to Leptochiton cancellatus (Mollusca, Polyplacophora). Journal of Submicroscopic Cytology and Pathology, 29:135151.Google ScholarPubMed
Ren, C.-Y., Liu, L.-Q., Zhou, Y.-H., Guo, J.-F., Yang, W.-X., and Li, Y. 2008. [Vase-shaped microfossils from Weng'an biota.] Journal of Earth Sciences and Environment, 30:249253. (In Chinese).Google Scholar
Runnegar, B. 1985a. Early Cambrian endolithic algae. Alcheringa, 9:179182.CrossRefGoogle Scholar
Runnegar, B. 1985b. Shell microstructures of Cambrian molluscs replicated by phosphate. Alcheringa, 9:245257.CrossRefGoogle Scholar
Sdzuy, K. 1969. Unter- und mittelkambrische Porifera (Chancelloriida und Hexactinellida). Paläontologische Zeitschrift, 43:115147.CrossRefGoogle Scholar
Skovsted, C. B. 2006. Small shelly fauna from the upper Lower Cambrian Bastion and Ella Island formations, North-East Greenland. Journal of Paleontology, 80:10871112.CrossRefGoogle Scholar
Soudry, D. and Lewy, Z. 1988. Microbially influenced formation of phosphate nodules and megafossil moulds (Negev, southern Israel). Palaeogeography, Palaeoclimatology, Palaeoecology, 64:1534.CrossRefGoogle Scholar
Sperling, E. A., Pisani, D., and Peterson, K. J. 2007. Poriferan paraphyly and its implications for Precambrian paleobiology, p. 355368. In Vickers-Rich, P. and Komarower, P. (eds.), The Rise and Fall of the Ediacaran Biota. Geological Society Special Publication, Vol. 286.Google Scholar
Steiner, M., Li, G.-X., Qian, Y., and Zhu, M.-Y. 2004. Lower Cambrian small shelly fossils of northern Sichuan and southern Shaanxi (China), and their biostratigraphic importance. Geobios, 37:259275.CrossRefGoogle Scholar
Steiner, M., Li, G.-X., Qian, Y., Zhu, M.-Y., and Erdtmann, B.-D. 2007. Neoproterozoic to Early Cambrian small shelly fossil assemblages and a revised biostratigraphic correlation of the Yangtze Platform (China). Palaeogeography, Palaeoclimatology, Palaeoecology, 254:6799.CrossRefGoogle Scholar
Vannier, J., Steiner, M., Renvoisé, E., Hu, S.-X., and Casanova, J.-P. 2007. Early Cambrian origin of modern food webs: Evidence from predator arrow worms. Proceedings of the Royal Society B, 274:627633.CrossRefGoogle ScholarPubMed
Vasil'eva, N. I. 1998. Melkaya Rakovinnaya Fauna i Biostratigrafiya Nizhnego Kembriya Sibirskoy Platformy. Vserossiyskiy Neftyanoy Nauchno-Issledovatel'skiy Geologorazvedochnyy Institut, Saint Petersburg, 139 p.Google Scholar
Vasil'eva, N. I. and Sayutina, T. A. 1988. Morfologicheskoe raznoobrazie skleritov khantselloriy, p. 190198. In Zhuravleva, I. T. and Repina, L. N. (eds.), Kembriy Sibiri i Sredney Azii. Trudy Institut Geologii i Geofiziki, Akademiya Nauk SSSR, Sibirskoe Otdelenie, Vol. 720.Google Scholar
Vinther, J. 2009. The canal system in sclerites of Lower Cambrian Sinosachites (Halkieriidae: Sachitida): Significance for the molluscan affinities of the sachitids. Palaeontology, 52:689712.CrossRefGoogle Scholar
Vinther, J. and Nielsen, C. 2005. The Early Cambrian Halkieria is a mollusc. Zoologica Scripta, 34:8189.CrossRefGoogle Scholar
Voronin, Yu. I., Voronova, L. G., Grigor'eva, N. V., Drozdova, N. A., Zhegallo, E. A., Zhuravlev, A. Yu., Ragozina, A. L., Rozanov, A. Yu., Sayutina, T. A., Sysoev, V. A., and Fonin, V. D. 1982. Granitsa dokembriya i kembriya v geosinklinal'nykh oblastyakh. Trudy Sovmestnaya Sovetsko-Mongol'skaya Paleontologicheskaya Ekspeditsiya, Vol. 18, 150 p.Google Scholar
Walcott, C. D. 1911. Middle Cambrian annelids. Smithsonian Miscellaneous Collections, 57:109144.Google Scholar
Walcott, C. D. 1920. Middle Cambrian Spongiae. Smithsonian Miscellaneous Collections, 67:261364.Google Scholar
Walliser, O. H. 1958. Rhombocorniculum comleyense n. gen., n. sp. (incertae sedis, Unterkambrium, Shropshire). Paläontologische Zeitschrift, 32:176180.CrossRefGoogle Scholar
Wang, M.-Z. and Xu, A.-D. 1987. [The establishment of Lower Cambrian Huoshaodian Formation and its significance in stratigraphy, Zhenba, southern Shaanxi.] Journal of Changchun College of Geology, 17:249254. (In Chinese).Google Scholar
Weedon, M. J. 1990. Shell structure and affinity of vermiform ‘gastropods.’ Lethaia, 23:297309.CrossRefGoogle Scholar
Williams, A. and Holmer, L. E. 2002. Shell structure and inferred growth, functions and affinities of the sclerites of the problematic Micrina. Palaeontology, 45:845873.CrossRefGoogle Scholar
Wrona, R. 2004. Cambrian microfossils from glacial erratics of King George Island, Antarctica. Acta Palaeontologica Polonica, 49:1356.Google Scholar
Xiao, S. and Knoll, A. H. 1999. Fossil preservation in the Neoproterozoic Doushantuo phosphorite Lagerstätte, South China. Lethaia, 32:219240.CrossRefGoogle ScholarPubMed
Xie, Y.-S. 1988. [Small shelly fossils in Qiongzhusi Stage of Lower Cambrian in Zhenba County Shaanxi Province.] Journal of Chengdu College of Geology, 15(4):2129. (In Chinese).Google Scholar
Xie, Y.-S. 1990. [The conodont-like fossils of Early Cambrian in Zhenba, Shanxi.] Journal of Chengdu College of Geology, 17(4):1622. (In Chinese).Google Scholar
Xing, Y.-S., Ding, Q.-X., Luo, H.-L., He, T.-G., and Wang, Y.-G., et al. 1984. [The Sinian–Cambrian boundary of China.] Bulletin of the Institute of Geology, Chinese Academy of Geological Sciences, 10:1262. (In Chinese).Google Scholar
Xue, Y.-S. and Zhou, C.-M. 2006. [Resedimentation of the Early Cambrian phosphatized small shell fossils and correlation of the Sinian–Cambrian boundary strata in the Yangtze Region, southern China.] Journal of Stratigraphy, 30:6474. (In Chinese).Google Scholar
Xue, Y.-S., Zhou, C.-M., and Tang, T.-F. 2002. [New material of animal fossils from the Upper Sinian of the Yangtze Region, southern China.] Acta Palaeontologica Sinica, 41:137142. (In Chinese).Google Scholar
Yang, X.-H. and He, T.-G. 1984. [New small shelly fossils from Lower Cambrian Meishucun Stage of Nanjiang Area, Northern Sichuan.] Professional Papers of Stratigraphy and Palaeontology, 13:3547. (In Chinese).Google Scholar
Yang, X.-H., He, Y.-X., and Deng, S.-H. 1983. [On the Sinian–Cambrian boundary and the small shelly fossil assemblages in Nanjiang area, Sichuan.] Bulletin of the Chengdu Institute of Geology and Mineral Resources, Chinese Academy of Geological Sciences, 4:91110. (In Chinese).Google Scholar
Yao, H.-Z., Huang, Z.-X., Xie, C.-F., and Zhang, K.-M. 1999. [The Cambrian lithostratigraphical sequence and sedimentary facies of Wanning Area, Hainan Island.] Journal of Stratigraphy, 23:270276. (In Chinese).Google Scholar
Yin, J.-C., Ding, L.-F., He, T.-G., Li, S.-L., and Shen, L.-J. 1980. [The Palaeontology and Sedimentary Environment of the Sinian System in Emei-Ganluo Area, Sichuan.] Geological College of Chengdu, Chengdu, 231 p. (In Chinese).Google Scholar
Yu, W. 1987. Yangtze micromolluscan fauna in Yangtze Region of China with notes on Precambrian–Cambrian boundary, p. 19344. In Stratigraphy and Palaeontology of Systemic Boundaries in China: Precambrian–Cambrian Boundary, Vol. 1. Nanjing University Publishing House, Nanjing.Google Scholar
Yue, Z. 1990. [Discovery of trilobites from the Xihaoping Member (Lower Cambrian) of the Dengying Formation in Fangxian County, Hubei Province.] Regional Geology of China, 1990:277282. (In Chinese).Google Scholar
Yue, Z. 1991. [Discovery of fused sclerites of Early Cambrian Phyllochiton and its relation with zhijinitids.] Kexue Tongbao, 36:4750. (In Chinese).Google Scholar
Yue, Z. 2004. Early Cambrian small shelly fossil Sinosachites from southwest China. Acta Palaeontologica Sinica, 43:164178.Google Scholar
Zhang, L.-Y. 1994. [A new progress in research on vase-shaped microfossils from the Dengying Formation of Sinian in southern Shaanxi Province.] Acta Geologica Gansu, 3(2):18. (In Chinese).Google Scholar
Zhang, L.-Y. and Li, Y. 1991. [The Late Sinian vasiform microfossils of Ningqiang, Shaanxi Province.] Bulletin of the Xi'an Institute of Geology and Mineral Resources, Chinese Academy of Geological Sciences, 31:7786. (In Chinese).Google Scholar
Zhang, Y., Yin, L.-M., Xiao, S., and Knoll, A. H. 1998. Permineralized fossils from the terminal Proterozoic Doushantuo Formation, South China. Paleontological Society Memoir, Number 50, 52 p.Google Scholar
Zhang, Z.-Y. 1994. [Comments on the “vase-shaped microfossils” from the Doushantuo Formation of the eastern Yangtze Gorges.] Acta Micropalaeontologica Sinica, 11:369371. (In Chinese).Google Scholar
Zhao, X. and Li, G.-X. 2006. [Early Cambrian sponge spicule fossils from Zhenba County, southern Shaanxi Province.] Acta Micropalaeontologica Sinica, 23:281294. (In Chinese).Google Scholar
Zhao, Z.-Q., Xing, Y.-S., Ding, Q.-X., Liu, G.-Z., Zhao, Y.-X., Zhang, S.-S., Meng, X.-Y., Yin, C.-Y., Ning, B.-R., and Han, P.-G. 1988. [The Sinian System of Hubei.] China University of Geosciences Press, Wuhan, 205 p. (In Chinese).Google Scholar