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Soft-bodied biota from the middle Cambrian (Drumian) Rockslide Formation, Mackenzie Mountains, northwestern Canada

Published online by Cambridge University Press:  09 March 2015

Julien Kimmig
Affiliation:
Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada, 〈j.kimmig@usask.ca〉
Brian R. Pratt
Affiliation:
Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada, 〈j.kimmig@usask.ca〉

Abstract

A new Burgess Shale-type Lagerstätte is described from the middle Cambrian (Series 3, Drumian) Rockslide Formation of the Mackenzie Mountains, Northwest Territories, Canada. The Rockslide Formation is a unit of deeper water ramp to slope, mixed carbonate, and siliciclastic facies deposited on the northwestern margin of Laurentia. At the fossil-bearing locality, the unit onlaps a fault scarp cutting lower Cambrian sandstones. There it consists of a succession of shale and thick-laminated to thin-bedded lime mudstone, calcareous sandstone, and greenish-colored calcareous mudstone, overlain by shallower water dolostones of the Avalanche Formation, which is indicative of an overall progradational sequence. The Rockslide Formation is of similar age to the Wheeler and Marjum formations of Utah, belonging to the Bolaspidella Biozone. Only two 1 m thick units of greenish mudstone exhibit soft-bodied preservation, with most specimens coming from the lower interval. However, the biota is common but not as diverse as that of other Lagerstätten such as the Burgess Shale in its type area. The shelly fauna is dominated by the hyolith Haplophrentis carinatus Matthew, 1899 along with sparse linguliformean brachiopods, agnostoid arthropods, and ptychoparioid trilobites. The nonmineralized biota includes the macrophytic alga Margaretia dorus Walcott, 1911, priapulid worms, and the carapaces of a number of arthropods. The arthropods belong to Isoxys mackenziensis n. sp., Tuzoia cf. T. guntheri Robison and Richards, 1981; Branchiocaris? sp., Perspicaris? dilatus Robison and Richards, 1981; and bradoriids, along with fragments of arthropods of indeterminate affinities. The style of preservation indicates that most soft parts underwent complete biodegradation, leaving just the more resistant materials such as chitinous arthropod cuticles. The range of preservation and similarity to the coeval biotas preserved in Utah suggests that the composition of this Lagerstätte is probably representative of the community living on the relatively deep-water ramp or slope during middle Cambrian time in Laurentia. This would argue that the extraordinary diversity of the Burgess Shale at Mount Field is anomalous.

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Copyright © 2015, The Paleontological Society 

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References

Abushik, A.F., 1960, First discovery of leperditaceans from the Cambrian of the Siberian Platform: Vestnik Leningradskogo Universitet, Seriya Geologii I Geografii, v. 6, p. 9398. [In Russian].Google Scholar
Aitken, J.D., Macqueen, R.W., and Usher, J.L., 1973, Reconnaissance studies of Proterozoic and Cambrian stratigraphy, lower Mackenzie River area (Operation Norman), District of Mackenzie: Geological Survey of Canada Paper 73-9, 178 p.Google Scholar
Allison, P.A., 1988, The role of anoxia in the decay and mineralization of proteinaceous macrofossils: Paleobiology, v. 14, p. 139154.Google Scholar
Babcock, L.E., and Robison, R.A., 1988, Taxonomy and paleobiology of some Middle Cambrian Scenella (Cnidaria) and hyolithids (Mollusca) from western North America: The University of Kansas Paleontological Contributions, no. 121, 22 p.Google Scholar
Billings, E., and Whiteaves, J.F., 1861, On some new or little known species of Lower Silurian fossils from the Potsdam group (Primordial Zone). Report on the Geology of Vermont: Claremont, Hew Hampshire, v. 2, p. 942960.Google Scholar
Briggs, D.E.G., 1976, The Arthropod Branchiocaris n. gen., Middle Cambrian, Burgess Shale, British Columbia: Geological Survey of Canada, Bulletin 264, 29 p.Google Scholar
Briggs, D.E.G., 1977, Bivalved arthropods from the Cambrian Burgess Shale of British Columbia: Palaeontology, v. 20, p. 595621.Google Scholar
Briggs, D.E.G., 1978, The morphology, mode of life, and affinities of Canadaspis perfecta (Crustacea: Phyllocarida), Middle Cambrian, Burgess Shale, British Columbia: Philosophical Transactions of the Royal Society of London, Series B, v. 281, p. 439487.Google Scholar
Briggs, D.E.G., 1992, Phylogenetic significance of the Burgess Shale crustacean Canadaspis: Acta Zoologica, v. 73, p. 293300.Google Scholar
Briggs, D.E.G., Erwin, D.H., and Collier, F.J., 1994, The Fossils of the Burgess Shale: Washington, D.C., Smithsonian Institution Press, 238 p.Google Scholar
Briggs, D.E.G., Lieberman, B.S., Hendricks, J.H., Halgedahl, S.L., and Jarrard, R.D., 2008, Middle Cambrian Arthropods from Utah: Journal of Paleontology, v. 82, p. 238254.Google Scholar
Butterfield, N.J., 1994, Burgess Shale-type fossils from a Lower Cambrian shallow-shelf sequence in northwestern Canada, Nature, v. 369, p. 477479.CrossRefGoogle Scholar
Butterfield, N.J., 1995, Secular distribution of Burgess Shale type preservation. Lethaia, v. 28, p. 113.Google Scholar
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, v. 70, p. 893899.Google Scholar
Butterfield, N.J., Balthasar, U., and Wilson, L.A., 2007, Fossil diagenesis in the Burgess Shale, Palaeontology, v. 50, p. 537543.Google Scholar
Caron, J.-B., and Jackson, D.A., 2008, Paleoecology of the Greater Phyllopod Bed community, Burgess Shale: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 258, p. 222256.Google Scholar
Caron, J.-B., Gaines, R.R., Aria, C., Mángano, M.G., and Streng, M., 2014, A new phyllopod bed-like assemblage from the Burgess Shale of the Canadian Rockies: Nature Communications, v. 5, doi:10.1038/ncomms4210.Google Scholar
Cecile, M.P., 1982, The lower Paleozoic Misty Creek embayment, Selwyn Basin, Yukon and Northwest Territories: Geological Survey of Canada, Bulletin 335, 78 p.Google Scholar
Chevier, T.S., and Turner, E.C., 2013, Lithostratigraphy of deep-water Paleozoic strata in the central misty creek embayment, Mackenzie Mountains, Northwest Territories: Geological Survey of Canada, Current Research 2013-2014, 21 p.Google Scholar
Chlupáč, I., and Kordule, V., 2002, Arthropods of Burgess Shale type from the Middle Cambrian of Bohemia (Czech Republic): Bulletin of the Czech Geological Survey, v. 77, p. 167182.Google Scholar
Collom, C.J., Johnston, P.A., and Powell, W.G., 2009, Reinterpretation of ‘Middle’ Cambrian stratigraphy of the rifted western Laurentian margin: Burgess Shale Formation and contiguous units (Sauk II Megasequence); Rocky Mountains, Canada: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 277, p. 6385.Google Scholar
Conway Morris, S., and Robison, R.A., 1988, More soft-bodied animals and algae from the Middle Cambrian of Utah and British Columbia: University of Kansas Paleontological Contributions, v. 122, 48 p.Google Scholar
Cuvier, G., 1797, Tableau élémentaire de l’histoire naturelle des animaux: Baudouin, Paris, 770 p.Google Scholar
D’Eichwald, E., 1840, Ueber das silurische Schichtensystem in Esthland: Aus dem ersten and zweiten Hefte der Zeithschrift für Natur und Heilkunde der medizinischen Akademi zu St. Petersburg, besonders abgedruckt, 210 p.Google Scholar
Dixon, J., and Stasiuk, L.D., 1998, Stratigraphy and hydrocarbon potential of Cambrian strata,Northern Interior Plains, Northwest Territories: Bulletin of Canadian Petroleum Geology, v. 46, p. 445470.Google Scholar
Dohrmann, M., Vargas, S., Janussen, D., Collins, A.G., and Wörheide, G., 2013, Molecular paleobiology of early-branching animals: integrating DNA and fossils elucidates the evolutionary history of hexactinellid sponges: Paleobiology, v. 39, p. 95108.Google Scholar
Duméril, A.M.C., 1806, Zoologie analytique ou méthode naturelle de classification des animaux: Paris, Allais, 364 p.Google Scholar
Edgecombe, G.D., and Legg, D.A., 2013, The arthropod fossil record, in Minelli, A., Boxshall, G., and Fusco, G., eds., Arthropod Biology and Evolution, Molecules, Development, Morphology: Berlin, Springer, p. 393415.Google Scholar
Endo, R., and Resser, C.E., 1937, The Sinian and Cambrian formations and fossils of southern Manchoukuo. Bulletin of the Manchurian Science Museum, v. 1, p. 1406.Google Scholar
Erwin, D.H., and Valentine, J. W., 2013, The Cambrian Explosion: the construction of animal biodiversity: Greenwood Village, Colorado, Roberts & Company, 406 p.Google Scholar
Fritz, W.H., 1979, Cambrian stratigraphic section between South Nahanni and Broken Skull Rivers, southern Mackenzie Mountains: Geological Survey of Canada, Paper 79-1B, p. 121125.Google Scholar
Fritz, W.H., Cecile, M.P., Norford, B.S., Morrow, D., and Geldsetzer, H.H.J., 1991, Cambrian to Middle Devonian assemblages, in Gabrielse, H., and Yorath, C.J., eds., Geology of the Cordilleran Orogen in Canada: Geological Survey of Canada, Geology of Canada, v. 4, p. 151218.Google Scholar
Fu, D., Zhang, X., Budd, G.E., Liu, W., and Pan, X., 2013, Ontogeny and dimorphism of Isoxyx auritus (Arthropoda) from the Early Cambrian Chengjiang biota,South China: Gondwana Research, v. 25, p. 975982.Google Scholar
Gabbott, S.E., Zalasiewicz, J., and Collins, D., 2008, Sedimentation of the Phyllopod Bed within the Cambrian Burgess Shale Formation of British Columbia: Journal of the Geological Society,London, v. 165, p. 307818.Google Scholar
Gabrielse, H., Blusson, S.L., and Roddick, J.A., 1973, Geology of Flat River, Glacier Lake, and Wrigley Lake map-areas,District of Mackenzie and Yukon Territory: Geological Survey of Canada, Memoir 366, 153 p.Google Scholar
Gaines, R.R., and Droser, M.L., 2010, The paleoredox setting of Burgess Shale-type deposits: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 297, p. 649661.Google Scholar
Gaines, R.R., Hammarlund, E.U., Hou, X., Qi, C., Gabbot, S.E., Zhao, Y., Peng, J., and Canfield, D.E., 2012, Mechanism for Burgess Shale-type preservation: Proceedings of the National Academy of Sciences, USA, v. 109, p. 5180–5184.Google Scholar
García-Bellido, D.C., Paterson, J.R., Edgecombe, G.D., Jago, J.B., Gehling, J.G., and Lee, M.S.Y., 2009, The bivalved arthropods Isoxys and Tuzoia with soft-part preservation from the Lower Cambrian Emu Bay Shale Lagerstätte (Kangaroo Island, Australia): Palaeontology, v. 52, p. 12211241.Google Scholar
Glaessner, M.F., 1979, Lower Cambrian Crustacea and annelid worms from Kangaroo Island, South Australia: Alcheringa, v. 3, p. 2131.Google Scholar
Gordey, S.P., and Anderson, J.G., 1993, Evolution of the northern Cordilleran miogeocline, Nahanni map area (105I),Yukon and Northwest Territories: Geological Survey Cananda, Memoir 428, 214 p.Google Scholar
Haeckel, G., 1866, Generale Morphologie der Organismen: Berlin, Georg Reimer, 462 p.Google Scholar
Handle, K.C., and Powell, W.G., 2012, Morphologically simple enigmatic fossils from the Wheeler Formation: A comparison with definitive algal fossils: Palaios, v. 27, p. 304316.Google Scholar
Harvey, T.H.P., and Butterfield, N.J., 2011, Great Canadian Lagerstätten 2. Macro- and microfossils of the Mount Cap Formation (Early and Middle Cambrian, Northwest Territories): Geoscience Canada, v. 38, p. 165173.Google Scholar
Hegna, T.A., Legg, D.A., Møller, O.S., Van Roy, P., and Lerosey-Aubril, R., 2013, The correct authorship of the taxon name ‘Arthropoda’: Arthropod Systematics and Phylogeny, v. 71, p. 7174.Google Scholar
Hinz-Schallreuter, I., 1993, Cambrian ostracodes mainly from Baltoscandia and Morocco: Archiv für Geschiebekunde, v. 1, p. 385448.Google Scholar
Hou, X., 1987, Early Cambrian large bivalved arthropods from Chengjiang,eastern Yunnan: Acta Palaeontologica Sinica, v. 26, p. 286298.Google Scholar
Hou, X., and Bergström, J., 1991, The arthropods of the Lower Cambrian Chengjiang fauna, with relationships and evolutionary significance, in Simonetta, A.M., and Conway Morris, S., eds., The Early Evolution of Metazoa and the Significance of Problematic Taxa: Cambridge: Cambridge University Press, p. 179187.Google Scholar
Hou, X., and Bergström, J., 1997, Arthropods of the Lower Cambrian Chengjiang fauna, southwest China: Fossils and Strata, v. 45, 116 p.Google Scholar
Hou, X.-G., Aldridge, R.J., Bergström, J., Siveter, Da.J., Siveter, De. J., and Feng, X-H., 2004, The Cambrian fossils of Chengjiang, China. The Flowering of Early Animal Life. Oxford, Blackwell, 233 p.Google Scholar
Huo, S.C., Shu, D., and Cui, Z.I., 1991, Cambrian Bradoriida of China: Beijing, Geological Publishing House, 249 p.Google Scholar
Ivantsov, A.Yu., 1990, First finds of phyllocarids in the Lower Cambrian of Yakutia. Paleontologicheskii Zhurnal, v. 1990, p. 130132. [in Russian].Google Scholar
Johnston, K.J., Johnston, P.A., and Powell, W.G., 2009a, A new, Middle Cambrian, Burgess Shale-type biota, Bolaspidella Zone, Chancellor Basin, southeastern British Columbia: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 277, p. 106126.Google Scholar
Johnston, P.A., Johnston, K.J., Collom, C.J., Powell, W.G., and Pollock, R.J., 2009b, Palaeontology and depositional environments of ancient brine seeps in the Middle Cambrian Burgess Shale at The Monarch, British Columbia, Canada: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 277, p. 86105.Google Scholar
King, W., 1846, Remarks on certain genera belonging to the class Palliobranchiata: Annals and Magazine of Natural History, v. 18, p. 2642.Google Scholar
Landing, E., Geyer, G., Brasier, M.D., and Bowring, S.A., 2013, Cambrian evolutionary radiation: context, correlation, and chronostratigraphy—overcoming deficiencies of the first appearance datum (FAD) concept: Earth-Science Reviews, v. 123, p. 133172.Google Scholar
Lee, M.S.Y., Soubrier, J., and Edgecombe, G.D., 2013, Rates of phenotypic and genomic evolution during the Cambrian Explosion: Current Biology, v. 23, p. 18891895.Google Scholar
Legg, D.A., and Vannier, J., 2013, The affinities of the cosmopolitan arthropod Isoxys and its implications for the origin of arthropods: Lethaia, v. 46, p. 540550.Google Scholar
Legg, D.A., and Caron, J.-B., 2014, New middle Cambrian bivalved arthropods from the Burgess Shale (British Columbia, Canada): Palaeontology, doi:10.1111/pala.12081.Google Scholar
Legg, D.A., Sutton, M.D., Edgecombe, G.D., and Caron, J.-B., 2014, Cambrian bivalved arthropod reveals origin of arthrodization:Proceedings of the Royal Society B, doi:10.1098/rspb.2012.1958.Google Scholar
Legg, D.A., Sutton, M.D., and Edgecombe, G.D., 2013, Arthropod fossil data increase congruence of morphological and molecular phylogenies: Nature Communications, v. 4, doi: 10.1038/ncomms3485.Google Scholar
Lieberman, B.S., 2003, A new soft-bodied fauna: The Pioche Formation of Nevada: Journal of Paleontology, v. 77, p. 674690.Google Scholar
Linnaeus, C., 1758, Systema Naturae Per Regna Tria Naturae: Secundum Classes, Ordines, Genera, Species, Cum Characteribus, Differentiis, Synonymis, Locis. 10th edition. Holmiae, Laurentii Salvii, 823 p.Google Scholar
Luo, H.L., Hu, S.X., Chen, L.Z., Zhang, S.S., and Tao, Y.H., 1999, Early Cambrian Chengjiang Fauna from Kunming Region, China: Kunming, Yunnan Science and Technology Press, 129 p. [in Chinese with English summary].Google Scholar
Luo, H.L., Jiang, Z., Wu, X., Song, X., and Liu, O., 1982, The Sinian–Cambrian boundary in eastern Yunnan, China: Kunming, People’s Publishing House of Yunnan, 265 p.Google Scholar
Luo, H.L., Fu, X.P., Hu, S.H., Li, Y., Chen, L.Z., You, T., and Liu, Q., 2006, New bivalved arthropods from the early Cambrian Guanshan fauna in the Kunming and Wuding area: Acta Palaeontologica Sinica, v. 45, p. 460472.Google Scholar
Luo, H.L., Li, Y., Hu, S.X., Fu, X.P., Hou, S.G., Liu, X.R., Chen, L.Z., Li, F.J., Pang, J.Y., and Liu, Q., 2008, Early Cambrian Malong Fauna and Guanshan Fauna from Eastern Yunnan, China: Kunming, Yunnan Science and Technology Press, 122 p. [in Chinese with English summary].Google Scholar
Mángano, M.G., Bromley, R.G., Harper, D.A.T., Nielsen, A.T., Smith, M.P., and Vinther, J., 2012, Nonbiomineralized carapaces in Cambrian seafloor landscapes (Sirius Passet, Greenland): Opening a new window into early Phanerozoic benthic ecology: Geology, v. 40, p. 519522.Google Scholar
Marek, L., 1963, New knowledge on the morphology of Hyolithes: Sborník geologickych věd, řada Paleontologie, v. 1, p. 5372.Google Scholar
Matthew, G.F., 1899, Studies on Cambrian faunas, no. 3: Upper Cambrian fauna of Mt. Stephen, British Columbia: Transactions of the Royal Society of Canada, Series 2, v. 5, p. 3966.Google Scholar
Nicholson, H.A., 1872, On the genera Cornulites and Tentaculites and on a new genus Conchicolites: American Journal of Science, v. 3, p. 202206.Google Scholar
Novozhilov, N.I., 1960, Rodklass Pseudocrustacea, in Orlov, Yu.A., ed., Osnovy Paleontologii, Arthropoda. Trilobitomorpha and Crustacea: Moscow, Nedra, Moscow, p. 199.Google Scholar
Peel, J.S., and Ineson, J.R., 2011, The extent of the Sirius Passet Lagerstätte (early Cambrian) of North Greenland: Bulletin of Geosciences, v. 86, p. 535543.Google Scholar
Poulsen, C., 1927, The Cambrian, Ozarkian and Canadian faunas of northwest Greenland: Meddelelser om Grønland, v. 70, p. 233343, pls. 14–21.Google Scholar
Pratt, B.R., 1989, Deep-water Girvanella-Epiphyton reef on a mid-Cambrian continental slope, Rockslide Formation, Mackenzie Mountains, Northwest Territories, in Geldsetzer, H.H.J., James, N.P., and Tebbutt, G.E., eds., Reefs, Canada and Adjacent Areas: Canadian Society of Petroleum Geologists, Memoir 13, p. 161164.Google Scholar
Pratt, B.R., 1992, Trilobites of the Marjuman and Steptoean Stages (Upper Cambrian), Rabbitkettle Formation, Southern Mackenzie Mountains, Northwest Canada: Palaeontographica Canadiana, v. 9, p. 179.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, v. 79, p. 10021011.Google Scholar
Raymond, P.E., 1935, Leanchoilia and other Mid-Cambrian Arthropoda: Bulletin of the Museum of Comparative Zoology, Harvard University, v. 76, p. 205230.Google Scholar
Rees, M.N., 1986, A fault-controlled trough through a carbonate platform: Middle Cambrian House Range embayment: Geological Society of America Bulletin, v. 97, p. 10541069.Google Scholar
Resser, C.E., 1929, New Lower and Middle Cambrian Crustacea: Proceedings of the U.S. National Museum, v. 76, p. 1–18.Google Scholar
Resser, C.E., 1937, Third contribution to nomenclature of Cambrian trilobites: Smithsonian Miscellaneous Collections, v. 95, no. 22, 29 p.Google Scholar
Resser, C.E., and Howell, B.F., 1938, Lower Cambrian Olenellus Zone of the Appalachians: Geological Society of America Bulletin, v. 49, p. 195248.Google Scholar
Reichenbach, H.G.L., 1834, Johann Christoph Mössler’s Handbuch der Gewächskunde, 3rd ed., 3, Phanerogamia: Altona: J. F. Hammerich, 768 p.Google Scholar
Richter, R., and Richter, E., 1927, Eine Crustacee (Isoxys carbonelli n. sp.) in den Archaeocyathus-Bildungen der Sierra Morena und ihre Stratigraphische Beurteilung: Senckenbergiana, v. 9, p. 188195.Google Scholar
Robison, R.A., 1991, Middle Cambrian biotic diversity: examples from four Utah lagerstätten, in Simonetta, A., and Conway Morris, S., eds., The Early Evolution of Metazoa and the Significance of Problematic Taxa: Cambridge, Cambridge University Press, p. 7798.Google Scholar
Robison, R.A., and Babckock, L.E., 2011, Systematics, paleobiology, and taphonomy of some exceptionally preserved trilobites from Cambrian Lagerstätten of Utah: Paleontological Contributions, v. 5, 47 p.Google Scholar
Robison, R.A., and Richards, B.C., 1981, Larger bivalve arthropods from the Middle Cambrian of Utah: The University of Kansas Paleontological Contributions, v. 106, 28 p.Google Scholar
Simonetta, A.M., and Delle Cave, L., 1975, The Cambrian non-trilobite arthropods from the Burgess Shale of British Columbia. A study of their comparative morphology, taxonomy and evolutionary significance: Palaeontographica Italiana, v. 69 (no. ser. 39), p. 137.Google Scholar
Sieveter, D.J., and Williams, M., 1997, Cambrian bradoriid and phosphatocopid arthropods of North America: Special Papers in Palaeontology, v. 57, 69 p.Google Scholar
Stein, M., 2010, A new arthropod from the early Cambrian of North Greenland, with a “great-appendage”-like antennule: Zoological Journal of the Linnean Society, v. 158, p. 477500.Google Scholar
Syssoiev [Sysoev, V.A.], 1958, Superorder Hyolithoidea, in Orlov, Yu. A., Luppov, N.P., and Drushchits, V.V., eds., Osnovy Paleontologii: Molluski−golovonogie, v. 2, Moscow: Akademia Nauk SSSR, Moscow, p. 184190 [in Russian].Google Scholar
Théel, H., 1906, Northern Arctic Invertebrates in the Collection of the Swedish State Museum. II. Priapulids, Echiurids etc: Kungliga Svenska Vetenskapsakademiens Handllingar, v. 40, 28 p.Google Scholar
Vannier, J., and Chen, J.Y., 2000, The Early Cambrian colonization of pelagic niches exemplified by Isoxys (Arthropoda), Lethaia, v. 33, p. 295311.Google Scholar
Vannier, J., Caron, J.-B., Yuan, J.-L., Briggs, D. G., Collins, D., Zhao, Y.-L., and Zhu, M.Y., 2007, Tuzoia: Morphology and lifestyle of a large bivalved arthropod of the Cambrian seas: Journal of Paleontology, v. 81, p. 445471.Google Scholar
von Siebold, C.T., 1848, Lehrbuch der vergleichenden Anatomie der Wirbellosen Thiere. Erster Theil, in von Siebold, C.T., and Stannius, H., eds., Lehrbuch der vergleichenden Anatomie: Berlin: Veit und Comp, p. 1679.Google Scholar
Waggoner, B., and Hagadorn, J.W., 2004, An unmineralized alga from the Lower Cambrian of California, USA: Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 231, p. 6783.Google Scholar
Walcott, C.D., 1890, The fauna of the Lower Cambrian or Olenellus Zone: Reports of the U.S. Geological Survey, v. 10, p. 509763.Google Scholar
Walcott, C.D., 1912, Cambrian geology and paleontology II; Middle Cambrian Branchiopoda, Malacostraca, Trilobita, and Merostomata: Smithsonian Miscellaneous Collections, v. 57, p. 145228.Google Scholar
Walcott, C.D., 1924, Cambrian and Ozarkian Brachiopoda, Cambrian Geology and Paleontology IV: Smithsonian Miscellaneous Collections, v. 67, p. 477554.Google Scholar
Walcott, C.D., 1931, Addenda to descriptions of Burgess Shale fossils: Smithsonian Miscellaneous Collections, v. 85, p. 146.Google Scholar
Wang, Y., Huang, D., and Lieberman, B.S., 2010, New Isoxys (Arthropoda) from the Cambrian Mantou Formation, Shandong Province: Acta Palaeontologica Sinica, v. 40, p. 398406.Google Scholar
Warming, E., 1884, Haandbog i den systematiske Botanik, 2nd ed., Copenhagen: P.G. Philipsens, 434 p.Google Scholar
Whittington, H.B., 1985, The Burgess Shale: New Haven, Connecticut, Yale University Press, 151 p.Google Scholar
Williams, M., Siveter, D.J., and Peel, J.S., 1996, Isoxys (Arthropoda) from the Early Cambrian Sirius Passet Lagerstätte, North Greenland: Journal of Paleontology, v. 70, p. 947954.Google Scholar
Yuan, J.-L., and Zhao, Y.-L., 1999, Tuzoia (bivalved arthropods) from the Lower-Middle Cambrian Kaili Formation of Taijiang, Guizhou: Palaeontologica Sinica, 38, supplement, p. 8893.Google Scholar
Yuan, J-L., Peng, J., and Zhao, Y.-L., 2011, New bivalve arthropods from the mid-Cambrian Kaili Biota of southeastern Guizhou, southwest China: Acta Geologica Sinica, v. 85, p. 801840.Google Scholar
Zhao, Y., Zhu, M., Babcock, L.E., Yuan, J., Parsley, R.L., Peng, J., Yang, X., and Wang, Y., 2005, Kaili Biota: A taphonomic window on diversification of metazoans from the basal Middle Cambrian: Guizhou, China: Acta Geologica Sinica, v. 79, p. 751765.Google Scholar
Zhao, Y., 2011, The Kaili Biota: Marine Organisms from 508 million years ago: Guiyang, China, Guizhou Science and Technology Press, 251 p.Google Scholar