Hostname: page-component-76fb5796d-45l2p Total loading time: 0 Render date: 2024-04-29T20:13:20.671Z Has data issue: false hasContentIssue false
  • English
  • Français

Early Middle Cambrian Trilobites from La Laja Formation, Cerro El Molle, Precordillera of Western Argentina

Published online by Cambridge University Press:  15 October 2015

Brian R. Pratt  and
Osvaldo L. Bordonaro
Brian R. Pratt
Affiliation:
Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada,
Osvaldo L. Bordonaro
Affiliation:
and IANIGLA–CONICET, Centro Científico Tecnológico, c.c. 131, 5500 Mendoza, Argentina,
Get access Rights & Permissions [Opens in a new window]

Abstract

A tectonically undeformed portion of the lower part of La Laja Formation is exposed at Cerro El Molle near San Juan, Precordillera of western Argentina. It consists of shallow-water, variably argillaceous lime mudstone and sporadically interbedded bioclastic grainstone deposited in an inner shelf setting. The El Estero Member and the basal 0.2 m of the Soldano Member contain a trilobite fauna of olenelloids and ‘simple’ ptychoparioids indicative of the early Cambrian (series 2, stage 4; Dyeran stage of Laurentia). The succeeding 50 m of the lower Soldano Member yield trilobites characteristic of the early middle Cambrian (series 3, stage 5; Delamaran stage of Laurentia). In ascending order of occurrence, Amecephalus arrojosensis, Kochiella maxeyi and Eokochaspis nodosa, along with several other taxa, including Ptychobaba n. gen. (type species Ptychoparella buttsi), belong to the traditional lower Plagiura–Poliella Biozone. However, while this fauna is similar to that of the Great Basin, the nominative species of the Eokochaspsis nodosa and overlying Amecephalus arrojosensis biozones recognized in southern Nevada occur in reverse order in the Soldano Member. This suggests that the ranges of these species overlap, thereby reducing the temporal resolution in the Precordillera into a combined Amecephalus arrojosensis–Eokochaspis nodosa Biozone. Argillaceous lime mudstones at the top yield Mexicella mexicana, indicative of the Mexicella mexicana Biozone recognized in the Great Basin, which is equivalent to the traditional Albertella Biozone of Laurentia. Because corynexochids are almost absent, the low-diversity ‘kochaspid’-dominated biofacies appears to typify the platform interior. The fauna is entirely Laurentian in composition, reinforcing notions of a close proximity of Cuyania to Laurentia during the Cambrian that enabled faunal migration and interchange. The absence of a late early Cambrian to early middle Cambrian hiatus correlative with the Hawke Bay Event, however, suggests no close affinity to the Iapetus-facing margin of eastern Laurentia.

Type
Research Article
Information
Journal of Paleontology , Volume 88 , Issue 5 , September 2014 , pp. 906 - 924
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

Aitken, J. D. 1997. Stratigraphy of the middle Cambrian platformal succession, southern Rocky Mountains. Geological Survey of Canada, Bulletin 398, 322 p.Google Scholar
Álvaro, J. J., Elicki, O., Geyer, G., Rushton, A. W. A., and Shergold, J. H. 2003. Palaeogeographical controls on the Cambrian trilobite immigration and evolutionary patterns reported in the western Gondwana margins. Palaeogeography, Palaeoclimatology, Palaeoecology, 195:5–35.Google Scholar
Babcock, L. E. 1994. Systematics and phylogenetics of polymeroid trilobites from the Henson Gletscher and Kap Stanton formations (middle Cambrian), North Greenland, p. 79–127. In Peel, J. S. (ed.), Palaeontology, stratigraphy and environmental setting of middle Cambrian outer shelf deposits, North Greenland. Grønlands geologiske Undersøgelse, Bulletin 169.Google Scholar
Benedetto, J. L. and Foglia, R. D. 2012. Lower and middle Cambrian rhynchonelliform brachiopods from the Precordillera terrane of Argentina. Journal of Paleontology, 86:273–281.Google Scholar
Benedetto, J. L., Sánchez, T. M., Carrera, M. G., Brussa, E. D., and Salas, M. J. 1999. Paleontological constraints on successive paleogeographic positions of Precordillera terrane during the early Paleozoic, p. 21–42. In Ramos, V. A. and Keppie, J. D. (eds.), Laurentia–Gondwana connections before Pangea. Geological Society of America, Special Paper 336.Google Scholar
Blaker, M. R. and Peel, J. S. 2012. Lower Cambrian Trilobites from North Greenland. Meddelelser om Grønland, Geoscience 35, 145 p.Google Scholar
Bordonaro, O. L. 1986. Bioestratigrafía del Cámbrico Inferior de San Juan. IV Congreso Argentino de Paleontología y Bioestratigrafía, Mendoza, Actas, 1:19–27.Google Scholar
Bordonaro, O. L. 2003. Review of the Cambrian stratigraphy of the Argentine Precordillera. Geologica Acta, 1:11–21.Google Scholar
Bordonaro, O. L. and Fojo, C. F. 2011. Bathyuriscus mendozanus (Rusconi, 1945), trilobites del Cámbrico medio de la Precordillera Argentina. Revista Española de Paleontología, 26:11–23.Google Scholar
Bordonaro, O., Banchig, A., Pratt, B. R., and Raviolo, M. 2008. Trilobite-based biostratigraphic model (biofacies and biozonation) for the middle Cambrian carbonate platform of the Argentine Precordillera. Geologica Acta, 6:115–129.Google Scholar
Bordonaro, O. L., Pratt, B. R., and Robledo, V. 2013. Systematic, morphometric and paleobiogeographic study of Blainia gregaria Walcott, 1916 (Trilobita, Ptychopariida), middle Cambrian of the Precordillera of western Argentina. Geological Journal, 47:126–141.Google Scholar
Borrello, A. V. 1963. Fremontella inopinata n. sp. del Cámbrico de Argentina. Ameghiniana, 3:51–55.Google Scholar
Borrello, A. V. 1964. Sobre la presencia del Cámbrico Inferior olenellidiano en la Sierra de Zonda, Precordillera de San Juan, Argentina. Ameghiniana, 3:313–317.Google Scholar
Chang, W. T. 1963. A classification of the lower and middle Cambrian trilobites from north and northeastern China, with description of new families and genera. Acta Palaeontologica Sinica, 11:447–487, 2 pls.Google Scholar
Cooper, G. A., Arellano, A. R., Johnson, J. H., Okulitch, V. J., Stoyanow, A., and Lochman, C. 1952. Cambrian stratigraphy and paleontology near Caborca, northwestern Sonora, Mexico. Smithsonian Miscellaneous Collections, 111(1), 184 p., 31 pls.Google Scholar
Dickerson, P. W. 2012. The circum-Laurentian carbonate bank, the western Ouachita-Cuyania Basin, and the prodigal Llanoria landmass, p. 959–984. In Derby, J. R., Fritz, R. D., Longacre, S. A., Morgan, W. A., and Sternbach, C. A. (eds.), The Great American Carbonate Bank: The geology and economic resources of the Cambrian–Ordovician Sauk Megasequence of Laurentia. AAPG Memoir 98.Google Scholar
Dickerson, P. W. and Keller, M. 1998. The Argentine Precordillera: its odyssey from the Laurentian Ouachita margin towards the Sierras Pampeanas of Gondwana, p. 85–105. In Pankhurst, R. J. and Rapela, C. W. (eds.), The Proto-Andean margin of Gondwana. Geological Society, London, Special Publication 142.Google Scholar
Eddy, J. D. and McCollum, L. B. 1998. Early middle Cambrian Albertella Biozone trilobites of the Pioche Shale, southeastern Nevada. Journal of Paleontology, 72:864–887.Google Scholar
Elicki, O. and Geyer, G. 2013. The Cambrian trilobites of Jordan—taxonomy, systematic and stratigraphic significance. Acta Geologica Polonica, 63:1–56.Google Scholar
Finney, S. C. 2007. The parautochthonous Gondwanan origin of the Cuyania (greater Precordillera) terrane of Argentina: a re-evaluation of evidence used to support an allochthonous Laurentian origin. Geologica Acta, 5:127–158.Google Scholar
Foglia, R. D. and Vaccari, N. E. 2010. Delamaran trilobites from the La Laja Formation, San Juan, Argentina. Ameghiniana, 47:431–445.Google Scholar
Foster, J. R. 2011. Trilobites and other fauna from two quarries in the Bright Angel Shale (middle Cambrian, series 3; Delameran), Grand Canyon National Park, Arizona, p. 99–120. In Hollingsworth, J. S., Sundberg, F. A., and Foster, J. R. (eds.), Cambrian stratigraphy and paleontology of northern Arizona and southern Nevada. Museum of Northern Arizona Bulletin 67.Google Scholar
Fritz, W. H. 1968. Lower and early middle Cambrian trilobites from the Pioche shale, east-central Nevada, U.S.A. Palaeontology, 11:183–235.Google Scholar
Fritz, W. H. 1991. Lower Cambrian trilobites from the Illtyd Formation, Wernecke Mountains, Yukon Territory. Geological Survey of Canada, Bulletin 409, 77 p.Google Scholar
Geyer, G. and Peel, J. S. 2011. The Henson Gletscher Formation, North Greenland, and its bearing on the global Cambrian Series 2–Series 3 boundary. Bulletin of Geosciences, 86:465–534.Google Scholar
Gómez, F. J., Ogle, N., Astini, R. A., and Kalin, R. M. 2007. Paleoenvironmental and carbon–oxygen isotope record of middle Cambrian carbonates (La Laja Formation) in the Argentine Precordillera. Journal of Sedimentary Research, 77:826–842.Google Scholar
Gunther, L. F. and Gunther, V. G. 1981. Some middle Cambrian fossils of Utah. Brigham Young University Geology Studies, 28, 87 p.Google Scholar
Hall, J. and Whitfield, R. P. 1877. Palaeontology (Part II. Fossils of the Potsdam Group). In C. King. Report of the United States geological exploration of the Fortieth Parallel, v. 4, pt. II. United States Army Engineer Department Professional Papers, 18:198–302.Google Scholar
Hu, C.-H. 1985. Ontogenetic development of Cambrian trilobites from British Columbia and Alberta, Canada (Part I). Journal of Taiwan Museum, 32:121–158.Google Scholar
Keller, M. 1999. Argentine Precordillera: sedimentary and plate tectonic history of a Laurentian crustal fragment in South America. Geological Society of America, Special Paper 341, 131 p.Google Scholar
Kobayashi, T. 1935. The Cambro–Ordovician formations and faunas of South Chosen: Palaeontology, Part III, Cambrian faunas of South Chosen with a special study on the Cambrian trilobite genera and families. Journal of the Faculty of Science, Tokyo University (sec. 2), 4:49–344, pls. 1–24.Google Scholar
Lochman, C. 1947. Analysis and revision of eleven Lower Cambrian trilobite genera. Journal of Paleontology, 21:59–71.Google Scholar
Lochman, C. 1948. New Cambrian trilobite genera from northeast Sonora, Mexico. Journal of Paleontology, 22:451–464.Google Scholar
Lorenz, Th. 1906. Beiträge zur Geologie und Palaeontologie von Ostasien unter besonderer Berüchsichting der Provinz Schantung in China, 2 Palaeontologischer Teil. Deutsche Geologische Gesellschaft, 58:53–108.Google Scholar
Matthew, G. F. 1887. Illustrations of the fauna of the St. John Group. 4. Part 1. Description of a new species of Paradoxides (Paradoxides regina). Part 2. The smaller trilobites with eyes (Ptychoparidae and Ellipsocephalidae). Transactions of the Royal Society of Canada, 5:115–166.Google Scholar
McCollum, L. B. and Sundberg, F. A. 2007. Cambrian trilobite biozonation of the Laurentian Delamaran Stage in the southern Great Basin, U.S.A.: implications for global correlations and defining a Series 3 global boundary stratotype, p. 147–156. In Laurie, J. R. and Patterson, J. R. (eds.), Papers in honour of John Helsby Shergold, 1938–2006. Association of Australasian Palaeontologists, Memoir 34.Google Scholar
McCollum, M. B. and McCollum, L. B. 2011. Depositional sequences in the Laurentian Delamaran Stage, southern Great Basin, U.S.A. In Hollingsworth, J. S., Sundberg, F. A., and Foster, J. R. (eds.), Cambrian stratigraphy and paleontology of northern Arizona and southern Nevada: Museum of Northern Arizona Bulletin, No. 67, p. 154–173.Google Scholar
Naipauer, M., Vujovich, G. I., Cingolani, C. A., and McClelland, W. C. 2010. Detrital zircon analysis from the Neoproterozoic–Cambrian sedimentary cover (Cuyania terrane), Sierra de Pie de Palo, Argentina: Evidence of a rift and passive margin system? Journal of South American Earth Sciences, 29:306–326.Google Scholar
Nielsen, A. T. and Schovsbo, N. H. 2011. The lower Cambrian of Scandinavia: depositional environment, sequence stratigraphy and palaeogeography. Earth-Science Reviews, 107:207–310.Google Scholar
Norford, B. S. 1968. A middle Cambrian Plagiura–Poliella faunule from southwest District of Mackenzie. Geological Survey of Canada, Bulletin 163, p. 29–38, pls. 4–6.Google Scholar
Palmer, A. R. 1971. The Cambrian of the Appalachian and eastern New England regions, eastern United States, p. 169–217. In Holland, C. H. (ed.), Cambrian of the New World. Wiley-Interscience, London.Google Scholar
Palmer, A. R. 1988. A proposed nomenclature for stages and series for the Cambrian of Laurentia. Canadian Journal of Earth Sciences, 35:323–328.Google Scholar
Palmer, A. R. and Campbell, D. P. 1976. Biostratigraphic implications of trilobite biofacies: Albertella Zone, middle Cambrian, western United States. Brigham Young Geology University Studies, 23:39–50.Google Scholar
Palmer, A. R. and Halley, R. B. 1979. Physical stratigraphy and trilobite biostratigraphy of the Carrara Formation (lower and middle Cambrian) in the southern Great Basin. U.S. Geological Survey Professional Paper 1,047, 131 p., 16 pls.Google Scholar
Palmer, A. R. and James, N. P. 1980. The Hawke Bay event: a circum-Iapetus regression near the lower middle Cambrian boundary, p. 15–18. In Wones, D. R. (ed.), The Caledonides in the U.S.A. IGCP Project 27, Caledonide Orogen, Proceedings, 1979. Virginia Polytechnic and State University, Memoir 2.Google Scholar
Peel, J. S. and Christie, R. L. 1982. Cambrian–Ordovician platform stratigraphy: correlations around Kane Basin. In Dawes, P. R. and Kerr, J. W. (eds.), Nares Strait and the Drift of Greenland: a conflict in plate tectonics. Meddelelser om Grønland, Geoscience, 8:117–135.Google Scholar
Poulsen, C. 1927. The Cambrian, Ozarkian and Canadian faunas of northwest Greenland. Meddelelser om Grønland, 70:233–343, pls. 14–21.Google Scholar
Poulsen, V. 1964. Contribution to the lower and middle Cambrian paleontology and stratigraphy of northwest Greenland. Meddelelser om Grønland, 164(6), 105 p., 3 pls.Google Scholar
Pratt, B. R. 1992. Trilobites of the Marjuman and Steptoean stages (upper Cambrian), Rabbitkettle Formation, southern Mackenzie Mountains, Northwest Canada. Palaeontographica Canadiana, 9, 179 p.Google Scholar
Pratt, B. R. and Bordonaro, O. L. 2007. Tsunamis in a stormy sea: middle Cambrian inner shelf limestones of western Argentina. Journal of Sedimentary Research, 77:256–262.Google Scholar
Pratt, B. R., Raviolo, M. M., and Bordonaro, O. L. 2012. Carbonate platform dominated by peloidal sands: Lower Ordovician La Silla Formation of the eastern Precordillera, San Juan, Argentina. Sedimentology, 59:843–866.Google Scholar
Ramos, V. A. 2004. Cuyania, an exotic block to Gondwana: review of a historical success and the present problems. Gondwana Research, 7:1,009–1,026.Google Scholar
Rasetti, F. 1951. Middle Cambrian stratigraphy and faunas of the Canadian Rocky Mountains. Smithsonian Miscellaneous Collections, 116(5), 277 p., 34 pls.Google Scholar
Rasetti, F. 1957. Additional fossils from the middle Cambrian Mt. Whyte Formation of the Canadian Rocky Mountains. Journal of Paleontology, 31:955–972.Google Scholar
Read, J. F. and Repetski, J. E. 2012. Cambrian–Lower Middle Ordovician passive carbonate margin, southern Appalachians, p. 357–382. In Derby, J. R., Fritz, R. D., Longacre, S. A., Morgan, W. A., and Sternbach, C. A. (eds.), The Great American Carbonate Bank: The geology and economic resources of the Cambrian–Ordovician Sauk Megasequence of Laurentia. AAPG Memoir 98.Google Scholar
Resser, C. E. 1935. Nomenclature of some Cambrian trilobites. Smithsonian Miscellaneous Collections, 93(5), 46 p.Google Scholar
Resser, C. E. 1936. Second contribution to nomenclature of Cambrian trilobites. Smithsonian Miscellaneous Collections, 95(4), 29 p.Google Scholar
Resser, C. E. 1937. Third contribution to nomenclature of Cambrian trilobites. Smithsonian Miscellaneous Collections, 95(22), 29 p.Google Scholar
Resser, C. E. 1938 a. Middle Cambrian fossils from Pend Oreille Lake, Idaho. Smithsonian Miscellaneous Collections, 97(3), 12 p., 1 pl.Google Scholar
Resser, C. E. 1938 b. Cambrian System (restricted) of the southern Appalachians. Geological Society of America, Special Paper 15, 140 p.Google Scholar
Resser, C. E. 1939 a. The Spence Shale and its fauna. Smithsonian Miscellaneous Collections, 97(12), 29 p, 6 pls.Google Scholar
Resser, C. E. 1939 b. The Ptarmigania strata of the northern Wasatch Mountains. Smithsonian Miscellaneous Collections, 98(24), 72 p., 14 pls.Google Scholar
Richter, R. 1932. Crustacea (Paläontologie), p. 840–864, figs. 1–65. In Dittler, R., Joos, G., Korschelt, E., Linek, G., Oltmanns, F., and Schaum, K. (eds.), Handwörterbuch der Naturwissenschaften (2nd edition). Gustav Fischer, Jena.Google Scholar
Robison, R. A. 1976. Middle Cambrian trilobite biostratigraphy of the Great Basin. Brigham Young Geology University Studies, 23:93–109.Google Scholar
Robison, R. A. and Babcock, L. E. 2011. Systematics, paleobiology, and taphonomy of some exceptionally preserved trilobites from Cambrian Lagerstätten of Utah. University of Utah, Paleontological Contributions, No. 5, 47 p.Google Scholar
Rominger, C. 1887. Description of primordial fossils from Mt. Stephens, N. W. Territory of Canada. Proceedings of the Academy of Natural Sciences of Philadelphia, 1887, p. 12–19.Google Scholar
Rushton, A. W. A. and Hughes, N. C. 1995. Biometry, systematics and biogeography of the late Cambrian trilobite Maladioidella abdita . Transactions of the Royal Society of Edinburgh: Earth Sciences, 86:247–256.Google Scholar
Sundberg, F. A. 1999. Redescription of Alokistocare subcoronatum (Hall and Whitfield, 1877), the type species of Alokistocare, and the status of Alokistocaridae Resser, 1939b (Ptychopariida: Trilobita, middle Cambrian). Journal of Paleontology, 73:1,126–1,143.Google Scholar
Sundberg, F. A. 2004. Cladistic analysis of early–middle Cambrian kochaspid trilobites (Ptychopariida). Journal of Paleontology, 78:920–940.Google Scholar
Sundberg, F. A. and McCollum, L. B. 2000. Ptychopariid trilobites of the lower–middle Cambrian boundary interval, Pioche Shale, southwestern Nevada. Journal of Paleontology, 74:604–630.Google Scholar
Sundberg, F. A. and McCollum, L. B. 2002. Kochiella Poulsen, 1927, and Hadrocephalites new genus (Trilobita: Ptychopariida) from the early middle Cambrian of western North America. Journal of Paleontology, 76:76–94.Google Scholar
Sundberg, F. A. and McCollum, L. B. 2003 a. Trilobites of the lower middle Cambrian Poliella denticulata Biozone (new) of southeastern Nevada. Journal of Paleontology, 77:331–359.Google Scholar
Sundberg, F. A. and McCollum, L. B. 2003 b. Early and mid Cambrian trilobites from the outer-shelf deposits of Nevada and California, U.S.A. Palaeontology, 46:945–986.Google Scholar
Swinnerton, H. H. 1915. Suggestions for a revised classification of trilobites. Geological Magazine, n. ser., 2:407–496, 538–545.Google Scholar
Taylor, M. E. and Halley, R. B., 1974. Systematics, environment, and biogeography of some late Cambrian and Early Ordovician trilobites of eastern New York State. U.S. Geological Survey, Professional Paper 834, 38 p., 4 pls.Google Scholar
Taylor, J. F., Repetski, J. E., Loch, J. D., and Leslie, S. A., 2012, Biostratigraphy and chronostratigraphy of the Cambrian–Ordovician great American carbonate bank, p. 15–35. In Derby, J. R., Fritz, R. D., Longacre, S. A., Morgan, W. A., and Sternbach, C. A. (eds.), The Great American Carbonate Bank: The Geology and Economic Resources of the Cambrian–Ordovician Sauk Megasequence of Laurentia. AAPG Memoir 98.Google Scholar
Thomas, W. A. and Astini, R. A. 2003. Ordovician accretion of the Argentine Precordillera terrane to Gondwana: a review. Journal of South American Earth Sciences, 16:67–79.Google Scholar
Tortello, F. 2011. Late middle Cambrian trilobites from El Tortoral, Mendoza, Argentina, p. 115–136. In Laurie, J. R., Patterson, J. R., and Brock, G. A. (eds.), Cambro–Ordovician studies IV. Memoirs of the Association of Australasian Palaeontologists, 42.Google Scholar
Voldman, A., Albanesi, G. L., and Ramos, V. A. 2008. Ordovician metamorphic event in the carbonate platform of the Argentine Precordillera: implications for the geotectonic evolution of the proto-Andean margin of Gondwana. Geology, 37:311–313.Google Scholar
Walch, J. E. I. 1771. Die Naturgeschichte der Versteinerungen, zur Erläuterung der Knorrischen Sammlung von Merkwürdigkeiten der Natur. Dritter Theil. P. J. Felßecker, Nürnberg, 235 p., 85 pls.Google Scholar
Walcott, C. D. 1886. Second contribution to the studies of the Cambrian faunas of North America. Bulletin of the U.S. Geological Survey, No. 30, 369 p., 33 pls.Google Scholar
Walcott, C. D. 1912. Cambrian geology and paleontology II. No. 8.—The Sardinian Cambrian genus Olenopsis in America. Smithsonian Miscellaneous Collections, 57:239–249.Google Scholar
Walcott, C. D. 1916 a. Cambrian geology and paleontology III. No. 3.—Cambrian trilobites. Smithsonian Miscellaneous Collections, 64:157–256.Google Scholar
Walcott, C. D. 1916 b. Cambrian geology and paleontology III. No. 5.—Cambrian trilobites. Smithsonian Miscellaneous Collections, 64:303–456.Google Scholar
Walcott, C. D. 1917 a. Cambrian geology and paleontology IV. No. 2.—The Albertella fauna in British Columbia and Montana. Smithsonian Miscellaneous Collections, 67:9–59.Google Scholar
Walcott, C. D. 1917 b. Cambrian geology and paleontology IV. No. 3.—Fauna of the Mount Whyte Formation. Smithsonian Miscellaneous Collections, 67:61–114.Google Scholar
Walcott, C. D. 1924. Cambrian geology and paleontology V. No. 2.—Cambrian and Ozarkian trilobites. Smithsonian Miscellaneous Collections, 75:53–60.Google Scholar
Walcott, C. D. 1925. Cambrian geology and paleontology V. No. 3.—Cambrian and Ozarkian trilobites. Smithsonian Miscellaneous Collections, 75:61–146.Google Scholar
Webster, M. 2011. The structure of cranidial shape variation in three early ptychoparioid trilobite species from the Dyerian–Delamaran (traditional “Lower–Middle” Cambrian) boundary interval of Nevada, U.S.A. Journal of Paleontology, 85:179–225.Google Scholar
Webster, M. and Zelditch, M. L. 2011. Evolutionary lability of integraton in Cambrian ptychoparioid trilobites. Evolutionary Biology, 38:144–162.Google Scholar
Whittington, H. B. and 16 others. 1997. Part O. Arthropoda 1. Trilobita, revised. Volume 1: Introduction, Order Agnostina, Order Redlichiida. Treatise on invertebrate paleontology. Geological Society of America and University of Kansas.Google Scholar
Yuan, J.-J. and Li, Y. 1999. Lower middle Cambrian boundary and trilobite faunas at Laoyingshan, Huainan, Anhui. Acta Palaeontologica Sinica, 36:494–524, 6 pls.Google Scholar