Intraspecific variation and taphonomic alteration in the Cambrian (Furongian) agnostoid Lotagnostus americanus: new information from China


Authors: Peng SC, Babcock LE, Zhu XJ, Ahlberg P, Terfelt F, Dai T

Published in: Bulletin of Geosciences, volume 90, issue 2; pages: 281 - 306; Received 31 January 2014; Accepted in revised form 14 November 2014; Online 9 February 2015

Keywords: Cambrian, Furongian, agnostoid, Lotagnostus americanus, China, Quebec,

full text (PDF, 5.22 MB)

Export to RIS


Supplementary material

Appendix (5862 kB)

Photographic equipment



The concept of the agnostoid arthropod species Lotagnostus americanus (Billings, 1860), which has been reported from numerous localities in the upper Furongian Series (Cambrian) of Laurentia, Gondwana, Baltica, Avalonia, and Siberia, is reviewed with emphasis on morphologic and taphonomic information afforded by large collections from Hunan in South China, Xinjiang in Northwest China, and Zhejiang in Southeast China. Comparisons are made with type and topotype material from Quebec, Canada, as well as material from elsewhere in Canada, the USA, the United Kingdom, Sweden, Russia, and Kazakhstan. The new information clarifies the limits of morphologic variability in L. americanus owing to ontogenetic changes and variation within holaspides, including inferred microevolution. It also provides details on apparent variation of taphonomic origin. The Chinese collections demonstrate a moderately wide variation in L. americanus, indicating that arguments favoring restriction of Lotagnostus species to narrowly defined, geographically restricted forms are unwarranted. Species described as L. trisectus (Salter, 1864), L. asiaticus Troedsson, 1937, and L. punctatus Lu, 1964, for example, fall within the range of variation observed in L. americanus, and are regarded as junior synonyms. The effaced form Lotagnostus obscurus Palmer, 1955 is removed from synonymy with L. americanus. A review of the stratigraphic distribution of L. americanus as construed here shows that the earliest occurrences of the species in all regions of the world are nearly synchronous.


AHLBERG, P. 2003. Trilobites and international tie points in the Upper Cambrian of Scandinavia. Geologica Acta 1, 127-134.

AHLBERG, P., AXHEIMER, N. & ROBISON, R.A. 2007. Taxonomy of Ptychagnostus atavus: A key trilobite in defining a global Cambrian stage boundary. Geobios 40, 709-714.View article

AHLBERG, P. & TERFELT, F. 2012. Furongian (Cambrian) agnostoids of Scandinavia and their implications for intercontinental correlation. Geological Magazine 149, 1001-1012.View article

ANGELIN, N.P. 1851. Palaeontologia Suecica, pars I: Iconographia Crustaceorum Formationis Transitionis. 24 pp. Weigel, Lund.

APOLLONOV, M.K. & CHUGAEVA, M.N. 1983. Some trilobites from the Cambrian-Ordovician boundary deposits in the Batyrbai Valley of the Lesser Karatau, 66-90. In APOLLONOV, M.K., BANDALETOV, S.M. & IVSHIN, N.K. (eds) The Lower Palaeozoic Stratigraphy and Palaeontology of Kazakhstan. Nauka, Alma-Ata. [in Russian]

APOLLONOV, M.K., CHUGAEVA, M.N. & DUBININA, S.V. 1984. Trilobites and conodonts from the Batyrbai section (Uppermost Cambrian - Lower Ordovician) in Malyi Karatau Range (Atlas of palaeontological plates). 48 pp. Nauka, Alma-Ata. [in Russian]

AXHEIMER, N., ERIKSSON, M.E., AHLBERG, P. & BENGTSSON, A. 2006. The middle Cambrian cosmopolitan key species Lejopyge laevigata and its biozone: new data from Sweden. Geological Magazine 143, 447-455.View article

BABCOCK, L.E, ROBISON, R.A, REES, M.N, PENG, S. & SALTZMAN, M.R. 2007. The Global boundary Stratotype Section and Point (GSSP) of the Drumian Stage (Cambrian) in the Drum Mountains, Utah, USA. Episodes 30, 85-95.

BABCOCK, L.E, AHLBERG, P., PENG, S., TERFELT, F. & ERIKSSON, M.E. 2012. Morphologic variation, taphonomy and biostratigraphic range of the agnostoid Lotagnostus (Cambrian: Furongian) from Sweden. Journal of Guizhou University (Natural Sciences) 29 (Sup. 1), 154-155.

BELT, T. 1867. On some new trilobites from the Upper Cambrian rocks of North Wales. Geological Magazine 4, 294-295.View article

BILLINGS, E. 1860. On some new species of fossils from the limestone near Point Levi, opposite Quebec. Canadian Naturalist and Geologist 5, 301-324.

BOROVIKOV, L.E. & KRYSKOV, L.N. 1963. Cambrian deposits in the Kendyktas Mountains (South Kazakhstan). Material on Geology and Mineral Deposits of Altai and Kasakhstan. Trudy Vsesoyuznogo nauchno-issledovatelyskogo geologicheskogo instituta (VSEGEI), New Series 94, 266-280. [in Russian]

CHOI, D.K., LEE, J.G. & SHEEN, B.C. 2004. Upper Cambrian agnostoid trilobites from the Machari Formation, Yongwol, Korea. Geobios 27, 159-189.View article

CLARK, T.H. 1924. The paleontology of the Beekmantown Series at Lévis, Quebec. Bulletins of American Paleontology 10, 1-134.

DAILY, B. & JAGO, J. B. 1975. The trilobite Lejopyge Hawle and Corda and the Middle-Upper Cambrian boundary. Palaeontology 18, 527-550.

DALMAN, J.W. 1828. Nya Svenska Paleader. Arsberättelse om Nyare Zoologiska Arbeten och Upptäckter, 134-135. Kongliga Svenska Vetenskaps-Akademiens Handlingar.

ERGALIEV, G.K. 1980. Middle and Upper Cambrian trilobites of the Malyi Karatau Range. 211 pp. Nauka, Alma-Ata. [in Russian]

ERGALIEV, G.K. 1983. Some trilobites from the Upper Cambrian and Lower Ordovician of the Greater Karatau and Ulutau, 35-66. In ApOLLONOV, M.K., BANDELETOV, S.M. & IVSHIN, N.K. (eds) The Lower Paleozoic Stratigraphy and Paleontology of Kazakhstan. Nauka, Alma-Ata. [in Russian]

HENNINGSMOEN, G. 1958. The Upper Cambrian fauna of Norway. Norsk Geologisk Tidsskrift 38, 179-196.

HOYBERGET, M. & BRUTON, D.L. 2008. Middle Cambrian trilobites of the suborders Agnostina and Eodiscina from the Oslo Region, Norway. Palaeontographica A286, 1-87.View article

HUTCHINSON, R.D. 1952. The stratigraphy and trilobite faunas of the Cambrian sedimentary rocks of Cape Breton Island, Nova Scotia. Geological Survey of Canada Memoir 263, 1-124.View article

JAGO, J.B. & COOPER, R.A. 2007. Middle Cambrian trilobites from Reilly Ridge, northern Victoria Land, Antarctica. Memoirs of the Australasian Association of Palaeontologists 34, 473-487.

KOBAYASHI, T. 1935. The Cambro-Ordovician formations and faunas of South Chosen, Palaeontology. Part 3, Cambrian faunas of South Chosen with a special study on the Cambrian trilobite genera and families. Journal of the Faculty of Science, Imperial University of Tokyo, Section II 4(2), 49-344.

LANDING, E., WESTROP, S.R. & ADRAIN, J.M. 2011. The Lawsonian Stage - the Eoconodontus notchpeakensis FAD and HERB carbon isotope excursion define a globally correlatable terminal Cambrian stage. Bulletin of Geosciences 86(3), 621-640.View article

LANDING, E., WESTROP, S.R. & MILLER, J.F. 2010. Globally practical base for the uppermost Cambrian (Stage 10) - FAD of the conodont Eoconodontus notchpeakensis and the Housian Stage, p. 18. In FATKA, O. & BUDIL, P. (eds) Prague 2010, the 15th Conference of the Cambrian Stage Subdivision Working Group, International Subcommission on Cambrian Stratigraphy; Abstracts and Excursion Guide. Czech Geological Survey, Prague.

LAZARENKO, N.P., GOGIN, I.Y., PEGEL, T.V. & ABAIMOVA, G.P. 2011. The Khos-Nelege River section of the Ogon’or Formation: a potential candidate for the GSSP of Stage 10, Cambrian System. Bulletin of Geosciences 86(3), 555-568.View article

LAZARENKO, N.P., GOGIN, I.Y., PEGEL, T.V., SUKHOV, S.S., ABAIMOVA, G.P., EGOROVA, L.I., FEDOROV, A.B., RAEVSKAYA, E.G. & USHATINSKAYA, G.T. 2008a. Excursion 1b. Cambrian stratigraphy of the northeastern Siberian Platform and potential stratotype of lower boundaries of proposed Upper Cambrian Chekurovkian and Nelegerian stages in the Ogon’or Formation section at the Khos-Nelege River; the boundaries are defined by the FAD of Agnostotes orientalis and Lotagnostus americanus, 61-139. In ROZANOV, A.Y. & VARLAMOV, A.I. (eds) The Cambrian System of the Siberian Platform, Part 2: North-East of the Siberian Platform. PIN RAS, Moskva & Novosibirsk.

LAZARENKO, N.P., PEGEL, T.V., SUKHOV, S.S., ABAIMOVA, G.P. & GOGIN, I.Y. 2008b. Type section of Upper Cambrian of Siberian Platform - Candidate of stage stratotype of International stratigraphic scale, 3-58. In BUDNIKOV, I.V. (ed.) Cambrian sections of Siberian Platform - candidates of stratotype subdividing International Stratigraphic Scale (Stratigraphy and Paleontology); Material for 13th International Field Conference of Cambrian Stage Subdivision Working Group. SB RAS Press, Novosibirsk. [in Russian]

LINNARSSON, J.G.O. 1869. Om Vestergötlands cambriska och siluriska aflagringar. Kongliga Svenska Vetenskaps-Akademiens Handlingar 8(2), 1-89.

LINNARSSON, J.G.O. 1879. Om faunan i kalken med Conocoryphe exsulans (“coronatuskalken”). Sveriges Geologiska Undersökning, Series C 35, 1-31.

LU, Y. 1954. Upper Cambrian trilobites from Santu, southeastern Kueichou. Acta Palaeontologica Sinica 2(2), 117-152. [in Chinese with English summary]

LU, Y. 1964. Trilobites, 31-41. In WANG, Y. (ed.) Index Fossils of South China. Science Press, Beijing. [in Chinese]

LU, Y., CHANG (ZHANG), W., CHU (ZHU), C. (Z.), CHIEN (QIAN), Y. & HSIANG (XIANG), L. 1965. Trilobites of China. 1-362 + 363-766 pp. Science Press, Beijing. [in Chinese]

LU, Y., CHU (ZHU), C.(Z.), CHIEN (QIAN), Y., LIN, H., ZHOU, Z. & YUAN, K. 1974. Bio-environmental control hypothesis and its application to the Cambrian biostratigraphy and palaeozoogeography. Memoirs of the Nanjing Institute of Geology and Palaeontology, Academia Sinica 5, 27-116 [in Chinese]

LU, Y. & LIN, H. 1980. Cambro-Ordovician boundary in western Zhejiang and the trilobites contained therein. Acta Palaeontologica Sinica 19, 118-135. [in Chinese]

LU, Y. & LIN, H. 1984. Late Cambrian and earliest Ordovician trilobites of Jiangshan-Changshan area, Zhejiang, 45-143. In NANJING INSTITUTE OF GEOLOGY AND PALAEONTOLOGY, ACADEMIA SINICA (ed.) Stratigraphy and Palaeontology of Systemic Boundaries in China, Cambrian-Ordovician Boundary, Volume 1. Anhui Science & Technology Publishing House, Hefei.

LU, Y. & LIN, H. 1989. The Cambrian trilobites of western Zhejiang. Palaeontologia Sinica, Whole Number 178, New Series B, 25, 1-287.

LU, Y. & QIAN (CHIEN), Y. 1983. Cambro-Ordovician trilobites from eastern Guizhou. Palaeontologia Cathayana 1, 1-105.

LUDVIGSEN, R. & WESTROP, S.R. 1989. Systematic Paleontology, 11-63. In LUDVIGSEN, R., WESTROP, S.R. & KINDLE, C.H. 1989 Sunwaptan (Upper Cambrian) trilobites of the Cow Head Group, western Newfoundland, Canada. Palaeontographica Canadiana 6, 1-175.

MÜLLER, K.J. & WALOSSEK, D. 1987. Morphology, ontogeny, and life habit of Agnostus pisiformis from the Upper Cambrian of Sweden. Fossils and Strata 19, 1-124.

ÖPIK, A.A. 1979. Middle Cambrian agnostids: systematics and biostratigraphy. Bulletin of the Bureau of Mineral Resources, Geology and Geophysics, Australia 172, 1-188.

PALMER, A.R. 1955. Upper Cambrian Agnostidae of the Eureka district, Nevada. Journal of Paleontology 29, 86-101.

PEGEL, T.V. 2000. Evolution of trilobite biofacies in Cambrian basins on the Siberian platform. Journal of Paleontology 74, 1000-1019.View article

PENG, S. 1984. Cambrian-Ordovician boundary in the Cili-Taoyuan border area, northwestern Hunan, 285-405. In NANJING INSTITUTE OF GEOLOGY AND PALAEONTOLOGY, ACADEMIA SINICA (ed.) Stratigraphy and paleontology of systemic boundaries in China, Cambrian and Ordovician boundary 1. Anhui Science and Technology Publishing House, Hefei.

PENG, S. 1990. Upper Cambrian in the Cili-Taoyuan area, Hunan, and its trilobite succession. Journal of Stratigraphy 14, 261-276. [in Chinese with English abstract]

PENG, S. 1992. Upper Cambrian biostratigraphy and trilobite faunas of the Cili-Taoyuan area, northwestern Hunan. Memoirs of the Association of Australasian Palaeontologists 13, 1-119.

PENG, S. & BABCOCK, L.E. 2005. Two Cambrian agnostoid trilobites, Agnostotes orientalis (Kobayashi, 1935) and Lotagnostus americanus (Billings, 1860): Key species for defining global stages of the Cambrian System. Geosciences Journal 9, 107-115.View article

PENG, S. & BABCOCK, L.E. 2008. Cambrian Period, 37-46. In OGG, J., OGG, G. & GRADSTEIN, F.M. (eds) The Concise Geologic Time Scale. 177 pp. Cambridge University Press, Cambridge.

PENG, S., BABCOCK, L.E. & AHLBERG, P. 2012a. Morphologic variation of Lotagnostus americanus from China and Russia. Journal of Guizhou University (Natural Sciences), 29 (Sup. 1), 182-183.

PENG, S., BABCOCK, L.E. & COOPER, R.A. 2012b. The Cambrian Period, 437-488. In GRADSTEIN, F.M., OGG, J.G., SCHMITZ, M.D. & OGG, G.M. (eds) The Geologic Time Scale 2012 (2 volumes). 1144 pp. Elsevier BV, Amsterdam, Boston, Heidelberg.

PENG, S., BABCOCK, L.E., ROBISON, R.A., LIN, H., REES, M.N. & SALTZMAN, M.R. 2004. Global Standard Stratotype-section and Point (GSSP) of the Furongian Series and Paibian Stage (Cambrian). Lethaia 37, 365-379.View article

PENG, S., BABCOCK, L.E., ZUO, J., LIN, H., ZHU, X., YANG, X., ROBISON, R.A., QI, Y., BAGNOLI, G. & CHEN, Y. 2009. The global boundary stratotype section and Point (GSSP) of the Guzhangian Stage (Cambrian) in the Wuling Mountains, northwestern Hunan, China. Episodes 32, 41-55.

PENG, S., BABCOCK, L.E., ZUO, J., ZHU, X., LIN, H., YANG, X., QI, Y., BAGNOLI, G. & WANG, L. 2012c. Global Standard Stratotype-section and Point (GSSP) for the base of the Jiangshanian Stage (Cambrian: Furongian) at Duibian, Jiangshan, Zhejiang, Southeast China. Episodes 35, 462-477.

PENG, S., BABCOCK, L.E., ZHU, X., ZUO, J. & DAI, T. 2014. A potential GSSP for the base of the uppermost Cambrian stage, coinciding with the first appearance of Lotagnostus americanus at Wa’ergang, Hunan, China. GFF 136, 208-213.View article

PENG, S. & ROBISON, R.A. 2000. Agnostoid biostratigraphy across the Middle-Upper Cambrian boundary in Hunan, China. Paleontological Society Memoir 53 (supplement to Journal of Paleontology 74), 1-104.View article

PRATT, B.R. 1992. Trilobites of the Marjuman and Steptoean stages (Upper Cambrian), Rabbitkettle Formation, southern Mackenzie Mountains, northwest Canada. Palaeontographica Canadiana 9, 1-179.

RASETTI, F. 1944. Upper Cambrian trilobites from the Lévis Conglomerate. Journal of Paleontology 18, 229-258.

ROBISON, R.A. 1972. Mode of life of agnostid trilobites. 24th International Geological Congress, Montreal, Session 7, 33-40.

ROBISON, R.A. 1982. Some Middle Cambrian agnostoid trilobites from western North America. Journal of Paleontology 56, 132-160.

ROBISON, R.A. 1984. Cambrian Agnostida of North America and Greenland, Part I; Ptychagnostidae. University of Kansas Paleontological Contributions, Paper 109, 1-59.

ROBISON, R.A. 1994. Agnostoid trilobites from the Henson Gletscher and Kap Stanton formations (Middle Cambrian), North Greenland. Gronlands Geologiske Undersogelse Bulletin 169, 25-77.

ROWELL, A.J., ROBISON, R.A. & STRICKLAND, D.K. 1982. Paleontology and chronocorrelation of a potential series boundary within the Cambrian. Journal of Paleontology 56, 161-182.

RUSCONI, C. 1950. Trilobitas y otros organismos del Cambrico de Canota. Revista del Museo de Historia Natural de Mendoza 4, 71-84.

RUSCONI, C. 1951. Trilobitas Cambricos del Cerro Pelado (Mendoza). Boletín Paleontologico de Buenos Aires 24, 1-4.

RUSHTON, A.W.A. 1978. Fossils from the middle-upper Cambrian transition in the Nuneaton district. Palaeontology 21, 245-283.

RUSHTON, A.W.A. 2009. Revision of the Furongian agnostoid Lotagnostus trisectus (Salter). Memoirs of the Association of Australasian Palaeontologists 37, 273-279.

SALTER, J.W. 1864. Figures and descriptions illustrative of British organic remains. Decade 11, Trilobites (chiefly Silurian). Memoirs of the Geological Survey of the United Kingdom, 1-64.

SHERGOLD, J.H. & LAURIE, J.R. 1997. Agnostina, 331-383. In KAESLER, R.L. (ed.) Treatise on Invertebrate Paleontology, Part O. Arthropoda 1. Trilobita, Revised. Geological Society of America & University of Kansas Press, Boulder & Lawrence.

SHERGOLD, J.H., LAURIE, J.R. & SUN, X. 1990. Classification and review of the trilobite Order Agnostida Salter. 1864: an Australian perspective. Bureau of Mineral Resources, Geology and Geophysics, Australia, Report 296, 1-93.

SOHN, J.W. & CHOI, D.K. 2007. Furongian trilobites from the Asioptychaspis and Quadraticephalus zones of the Hwajeol Formation, Taebaeksan Basin, Korea. Geosciences Journal 11, 297-314.View article

TAYLOR, M.E. 1976. Indigenous and redeposited trilobites from Late Cambrian basinal environments of central Nevada. Journal of Paleontology 50, 668-700.

TAYLOR, M.E. & COOK, H.E. 1976. Continental shelf and slope facies of the Upper Cambrian and lowest Ordovician of Nevada. Brigham Young University Geology Studies 23, 181-214.

TERFELT, F. & AHLBERG, P. 2010. Pseudagnostus rugosus Ergaliev, 1980: a key agnostoid species for intercontinental correlation of upper (Cambrian) Furongian strata. Geological Magazine 147, 789-796.View article

TERFELT, F., AHLBERG, P. & ERIKSSON, M.E. 2011. Complete record of Furongian polymerid trilobites and agnostoids of Scandinavia - a biostratigraphical scheme. Lethaia 44, 8-14.View article

TERFELT, F. & AHLGREN, J. 2007. Macropyge (Promacropyge) scandinavica new species; the first macropyginid trilobite recorded from the Furongian of Baltica. Journal of Paleontology 81, 1516-1522.View article

TERFELT, F., ERIKSSON, M.E., AHLBERG, P. & BABCOCK, L.E. 2008. Furongian Series (Cambrian) biostratigraphy of Scandinavia - a revision. Norwegian Journal of Geology 88, 73-87.

TROEDSSON, G.T. 1937. On the Cambro-Ordovician faunas of western Quruq Tagh, eastern Tien-Shan. Palaeontologia Sinica B2, 1-74.

TULLBERG, S. 1880. Om Agnostus-arterna i de kambriska aflagringarne vid Andrarum. Sveriges Geologiska Undersökning C42, 1-38.

WALLERIUS, I.D. 1895. Undersökningar öfver zonen med Agnostus laevigatus i Vestergötland: Jämte en inledande öfversikt af Vestergötlands samtliga Paradoxideslager. 72 pp. Hjalmar Möller, Lund.

WESTERGARD, A.H. 1922. Sveriges olenidskriffer. Sveriges Geologiska Undersökning Ca 18, 1-205.

WESTERGARD, A.H. 1946. Agnostidea of the Middle Cambrian of Sweden. Sveriges Geologiska Undersökning C477, 1-141.

WESTROP, S.R. 1995. Sunwaptan and Ibexian (Upper Cambrian-Lower Ordovician) trilobites from the Rabbitkettle Formation, Mountain River region, northern Mackenzie Mountains, northwest Canada. Palaeontographica Canadiana 12, 1-75.

WESTROP, S.R., ADRAIN, J.M. & LANDING, E. 2011. The Cambrian (Sunwaptan, Furongian) agnostoid arthropod Lotagnostus Whitehouse, 1936, in Laurentian and Avalonian North America: systematics and biostratigraphic significance. Bulletin of Geosciences 86(3), 569-594.View article

YIN, G. & LEE (LI), S. 1978. Trilobita, 385-595. In GUIZHOU WORKING TEAM ON STRATIGRAPHY AND PALAEONTOLOGY (ed.) Palaeontological Atlas of Southwest China, Guizhou Province (1): Cambrian-Devonian. Geological Publishing House, Beijing. [in Chinese]

ZHAO, J. (ed.) 1963. Handbook of Index fossils of China, Xibei (Northwest China) Region. 179 pp. Science Press, Beijing. [in Chinese]