Hostname: page-component-8448b6f56d-c47g7 Total loading time: 0 Render date: 2024-04-24T21:08:38.464Z Has data issue: false hasContentIssue false
  • English
  • Français

The Early Cambrian trilobite Family Emuellidae Pocock, 1970: Systematic position and revision of Australian species

Published online by Cambridge University Press:  20 May 2016

John R. Paterson  and
Gregory D. Edgecombe
John R. Paterson
Affiliation:
Centre for Ecostratigraphy and Paleobiology, Department of Earth and Planetary Sciences, Macquarie University NSW 2109, Australia,
Gregory D. Edgecombe
Affiliation:
Australian Museum, 6 College Street, Sydney NSW 2010, Australia,
Get access Rights & Permissions [Opens in a new window]

Abstract

The family Emuellidae Pocock, 1970 was established for Emuella Pocock, 1970 and Balcoracania Pocock, 1970 from the Lower Cambrian of South Australia. Based on their peculiar trunk tagmosis, emuellids have been interpreted as the sister group of all other trilobites with dorsal facial sutures, and classified as high as the ordinal level. Cladistic analysis with a range of exemplar taxa of the Olenellina and Redlichiina instead resolves the emuellids within the Redlichiina, with tagmosis into a prothorax and opisthothorax (“telosoma”) nonhomologous in olenellines and emuellids. A taxonomic revision of Australian species identifies Balcoracania flindersi as a junior subjective synonym of B. dailyi, whereas the two named species of Emuella are considered to be distinct. Balcoracania dailyi possesses up to 103 thoracic segments, the maximum number recorded in any trilobite.

Type
Research Article
Information
Journal of Paleontology , Volume 80 , Issue 3 , May 2006 , pp. 496 - 513
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

Ahlberg, P., and Bergström, J. 1978. Lower Cambrian ptychopariid trilobites from Scandinavia. Sveriges Geologiska Undersökning, Ser. Ca, 49:5–41.Google Scholar
Ahlberg, P., Bergström, J., and Johansson, J. 1986. Lower Cambrian olenellid trilobites from the Baltic Faunal Province. Geologiska Föreningens i Stockholm Förhandlingar, 108:39–56.CrossRefGoogle Scholar
Ax, P. 1987. The Phylogenetic System. John Wiley & Sons, New York, 340 p.Google Scholar
Barrande, J. 1846. Notice Préliminaire sur le Système Silurien et les Trilobites de Bohême. Hirschfeld, Leipzig, 97 p.Google Scholar
Bell, G. K. Jr. 1931. The disputed structures of the Mesonacidae and their significance. American Museum Novitates, 475:1–23.Google 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, 9:1–364.Google Scholar
Bergström, J. 1973. Organization, life, and systematics of trilobites. Fossils and Strata, 2:1–69.CrossRefGoogle Scholar
Bergström, J., and Levi-Setti, R. 1978. Phenotypic variation in the Middle Cambrian trilobite Paradoxides davidis Salter at Manuels, Southeast Newfoundland. Geologica et Palaeontologica, 12:1–40.Google Scholar
Briggs, D. E. G., and Fortey, R. A. 1992. The Early Cambrian radiation of arthropods, p. 335–373. In Lipps, J. H. and Signor, P. W. (eds.), Origin and Early Evolution of the Metazoa. Plenum Press, New York.CrossRefGoogle Scholar
Chapman, F. 1929. On some trilobites and brachiopods from the Mount Isa district, N.W. Queensland. Proceedings of the Royal Society of Victoria, 41:206–216.Google Scholar
Chatterton, B. D. E., and Speyer, S. E. 1997. Ontogeny, p. O173–O247. In Kaesler, R. L. (ed.), Treatise on Invertebrate Paleontology. Pt. O. Arthropoda 1, Trilobita (revised). Geological Society of America and University of Kansas Press, Lawrence.Google Scholar
Cisne, J. L. 1975. Anatomy of Triarthrus and the relationships of the Trilobita. Fossils and Strata, 4:45–63.CrossRefGoogle Scholar
Cisne, J. L. 1981. Triarthrus eatoni (Trilobita): Anatomy of its exoskeletal, skeletomuscular, and digestive systems. Palaeontographica Americana, 9:99–142.Google Scholar
Cobbold, E. S. 1935. A new genus of the Trilobita and a new species of the Conchostraca from the Cambrian of the Carteret region, N. W. France. Annals and Magazine of Natural History, series 10, 15:381–392.Google Scholar
Cossmann, M. 1902. Rectification de la nomenclature. Revue Critique de Paléozoologie, 16:52.Google Scholar
Demokidov, K. K., and Lazarenko, N. P. 1964. Stratigrafia verkhnego Dokembriia i Kembriia i Nizhnekembriiskie trilobity severnoi chasti srednei sibiri i ostrovov sovetskoi Arktiki [Stratigraphy of the upper Precambrian and Cambrian and Lower Cambrian trilobites in the northern part of central Siberia and the islands of the Soviet Arctic]. Trudy Nauchno-Issledovatel'skogo Instituta Geologii Arktiki, 137:1–288. (In Russian) Google Scholar
Emmons, E. 1844. The Taconic System, Based on Observations in New York, Massachusetts, Maine, Vermont and Rhode Island. Albany, New York, 653 p.Google Scholar
Fortey, R. A. 1990. Ontogeny, hypostome attachment and trilobite classification. Palaeontology, 33:529–576.Google Scholar
Fortey, R. A., and Whittington, H. B. 1989. The Trilobita as a natural group. Historical Biology, 2:125–138.Google Scholar
Fritz, W. H. 1972. Lower Cambrian trilobites from the Sekwi Formation type section, Mackenzie Mountains, northwestern Canada. Geological Survey of Canada Bulletin, 212:1–90.Google Scholar
Fritz, W. H. 1992. Walcott's Lower Cambrian olenellid trilobite collection 61K, Mount Robson area, Canadian Rocky Mountains. Geological Survey of Canada Bulletin, 432:1–65.Google Scholar
Fritz, W. H. 1995. Esmeraldina rowei and associated Lower Cambrian trilobites (1f fauna) at the base of Walcott's Waucoban Series, southern Great Basin, U.S.A. Journal of Paleontology, 69:708–723.CrossRefGoogle Scholar
Geyer, G. 1996. The Moroccan fallotaspidid trilobites revisited. Beringeria, 18:89–199.Google Scholar
Gravestock, D. I. 1995. Early and Middle Palaeozoic, p. 3–61. In Drexel, J. F. and Priess, W. V. (eds.), The Geology of South Australia. Vol. 2. The Phanerozoic. Mines and Energy, South Australia, Bulletin 54.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, 282:1–344.Google Scholar
Hahn, G. 1989. Reconstruction of the phylogenetic relationships among the higher taxa of trilobites. Abhandlungen des Naturwissenschaftlichen Vereins in Hamburg, 28:187–199.Google Scholar
Hall, J. 1838. Descriptions of two species of trilobites belonging to the genus Paradoxides . American Journal of Science, 13:139–142.Google Scholar
Hughes, N. C., and Chapman, R. E. 1995. Growth and variation in the Silurian proetide trilobite Aulacopleura konincki and its implications for trilobite palaeobiology. Lethaia, 28:333–353.CrossRefGoogle Scholar
Hughes, N. C., Chapman, R. E., and Adrain, J. M. 1999. The stability of thoracic segmentation in trilobites: A case study in developmental and ecological constraints. Evolution and Development, 1:24–35.CrossRefGoogle ScholarPubMed
Hupé, P. 1953. Contribution à l'étude du Cambrien inférieur et du Précambrien III de l'Anti-Atlas Marocain. Direction de la Production Industrielle et des Mines, Division des Mines et de la Géologie, Service Géologique, Notes et Mémoires, 103:1–402.Google Scholar
Hupé, P., and Abadie, J. 1950. Sur l'existence de Trilobites du Cambrien inférieur asiatique dans l'Anti-Atlas marocain. Comptes Rendus de l'Academie de Sciences, 230:2112–2113.Google Scholar
Jago, J. B., Lin, T. R., and Dunster, J. N. 2002. A new species of the trilobite Abadiella from the Lower Cambrian of the eastern Officer Basin, South Australia. Acta Palaeontologica Sinica, 41:428–433.Google Scholar
Jell, P. A. 2003. Phylogeny of Early Cambrian trilobites. Special Papers in Palaeontology, 70:45–57.Google Scholar
Kautsky, F. 1945. Die Unterkambrische Fauna vom Aistjakk in Lappland (Die Larven von Strenuella). Geologiska Föreningens i Stockholm Föerhandlingar, 67:129–211.Google Scholar
Khomentovskii, V. V., and Repina, L. N. 1965. Nezhnii Kembrii Stratotipicheskogo razreza Sibiri [The Lower Cambrian Stratotype section of Siberia]. Sibirskoe Otdelenie, Institut Geologii i Geofiziki, Akademiia Nauk SSSR, p. 1–196. (In Russian)Google Scholar
Kryskov, L. N., Lazarenko, N. P., Ogienko, L. V., and Chernysheva, N. E. 1960. [New early Paleozoic trilobites of eastern Siberia and Kazakhstan], p. 211–255. In Markovsky, B. P. (ed.), [New Species of Prehistoric Plants and Invertebrates of the USSR] Vol. 1. Pt. 2. VSEGEI, Moscow.Google Scholar
Lauterbach, K.-E. 1980. Schlüsselereignisse in der Evolution des Grundplans der Arachnata (Arthropoda). Abhandlungen des Naturwissenschaftlichen Vereins in Hamburg, 23:163–327.Google Scholar
Lauterbach, K.-E. 1983. Synapomorphien zwischen Trilobiten- und Cheliceratenzweig der Arachnata. Zoologischer Anzeiger, 210:213–218.Google Scholar
Lauterbach, K.-E. 1989. Trilobites and phylogenetic systematics: A reply to G. Hahn. Abhandlungen des Naturwissenschaftlichen Vereins in Hamburg, 28:201–211.Google Scholar
Leanza, A. F. 1949. Olenopsis Ameghino 1889 (un roedor) versus Olenopsis Bornemann 1891 (un trilobite). Asociacion Geologia Argentina (Buenos Aires), Revista, 4:36.Google Scholar
Lermontova, E. V. 1951. Nizhnekembriiskie trilobity i brakhiopody Vostochnoi Sibiri [Lower Cambrian trilobites and brachiopods from eastern Siberia]. Vsesoiuznyj Nauchno-Issledovatel'skij Geologicheskij Institut (VSEGEI), Gosudarstvennoe Izdatel'stvo, Moscow, 218 p. (In Russian) Google Scholar
Levi-Setti, R. 1993. Trilobites (second edition). The University of Chicago Press, Chicago, 342 p.Google Scholar
Lieberman, B. S. 1998. Cladistic analysis of the Early Cambrian olenelloid trilobites. Journal of Paleontology, 72:59–78.Google Scholar
Lieberman, B. S. 1999. Systematic revision of the Olenelloidea (Trilobita, Cambrian). Bulletin of the Peabody Museum of Natural History, Yale University, 45:1–150.Google Scholar
Lieberman, B. S. 2001. Phylogenetic analysis of the Olenellina Walcott, 1890 (Trilobita, Cambrian). Journal of Paleontology, 75:96–115.2.0.CO;2>CrossRefGoogle Scholar
Lieberman, B. S. 2002. Phylogenetic analysis of some basal Early Cambrian trilobites, the biogeographic origins of the Eutrilobita, and the timing of the Cambrian radiation. Journal of Paleontology, 76:692–708.Google Scholar
Lin, T. R. 1990. Application of cluster analysis to taxonomy of super-families and families of suborder Redlichiina (Trilobita). Acta Palaeontologica Sinica, 29:94–105. (In Chinese with English summary) Google Scholar
Linnarsson, J. G. O. 1871. Om några försteningar från Sveriges och Norges ‘primordialzon.’ Öfversigt af Kongliga Svenska Vetenskaps-Akademiens Förhandlingar, 6:789–796.Google Scholar
Lochman, C. 1956. Stratigraphy, paleontology, and paleogeography of the Elliptocephala asaphoides strata in Cambridge and Hoosick Quadrangles, New York. Bulletin of the Geological Society of America, 67:1331–1396.CrossRefGoogle Scholar
Lu, Y. H. 1940. On the ontogeny and phylogeny of Redlichia intermediata Lu (sp. nov.). Acta Geologica Sinica, 20:333–342. (In Chinese with English summary) Google Scholar
Lu, Y. H. 1950. On the genus Redlichia with description of its new species. Geological Review, 15:157–170.Google Scholar
Lu, Y. H., and Dong, N. T. 1952. Revision of the Cambrian type sections of Shantung. Acta Geologica Sinica, 32:164–201.Google Scholar
McNamara, K. J. 1981. Paedomorphosis in Middle Cambrian xystridurine trilobites from northern Australia. Alcheringa, 5:209–224.CrossRefGoogle Scholar
McNamara, K. J. 1983. Progenesis in trilobites. Special Papers in Palaeontology, 30:59–68.Google Scholar
Meneghini, G. 1882. Fauna Cambriana dell'Iglesiente in Sardegna. Atti della Società Toscana Scienze Naturali, Processi Verbali, 3:158–166.Google Scholar
Minelli, A., Fusco, G., and Hughes, N. C. 2003. Tagmata and segment specification in trilobites. Special Papers in Palaeontology, 70:31–43.Google Scholar
Moore, P. S. 1979. Stratigraphy and depositional environments of the Billy Creek Formation (Cambrian), central and northern Flinders Ranges, South Australia. Transactions of the Royal Society of South Australia, 103:197–211.Google Scholar
Moore, P. S. 1980. Stratigraphy and depositional environments of the Billy Creek Formation (Cambrian), east of the Flinders Ranges, South Australia. Transactions of the Royal Society of South Australia, 104:117–132.Google Scholar
Nedin, C. 1995. The Emu Bay Shale, a Lower Cambrian fossil Lagerstätten, Kangaroo Island, South Australia. Memoirs of the Association of Australasian Palaeontologists, 18:31–40.Google Scholar
Nedin, C., and Jenkins, R. J. F. 1999. Heterochrony in the Cambrian trilobite Hsuaspis . Alcheringa, 23:1–7.Google Scholar
Neltner, L., and Poctey, N. 1950. Quelques faunes géorgiennes du Maroc. Notes et Mémoires du Service Géologiques du Maroc, 74:53–83.Google Scholar
Nicosia, M. L., and Rasetti, F. 1970. Revisione dei trilobite del Cambriano dell'Iglesiente (Sardegna) descritti da Meneghini. Atti della Accademia Nazionale dei Lincei, Memorie, 10:1–18.Google Scholar
Öpik, A. A. 1968. The Ordian Stage of the Cambrian and its Australian Metadoxididae. Bureau of Mineral Resources, Geology and Geophysics Bulletin, 92:133–169.Google Scholar
Öpik, A. A. 1970. Redlichia of the Ordian (Cambrian) of northern Australia and New South Wales. Bureau of Mineral Resources, Geology and Geophysics Bulletin, 114:1–66.Google Scholar
Öpik, A. A. 1975a. Templetonian and Ordian xystridurid trilobites of Australia. Bureau of Mineral Resources, Geology and Geophysics Bulletin, 121:1–84.Google Scholar
Öpik, A. A. 1975b. Cymbric Vale fauna of New South Wales and Early Cambrian biostratigraphy. Bureau of Mineral Resources, Geology and Geophysics Bulletin, 159:1–74.Google Scholar
Palmer, A. R. 1957. Ontogenetic development of two olenelloid trilobites. Journal of Paleontology, 31:105–128.Google Scholar
Palmer, A. R. 1998. Terminal Early Cambrian extinction of the Olenellina: Documentation from the Pioche Formation, Nevada. Journal of Paleontology, 72:650–672.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. United States Geological Survey Professional Paper, 1047:1–131.Google Scholar
Palmer, A. R., and Repina, L. N. 1993. Through a glass darkly: Taxonomy, phylogeny, and biostratigraphy of the Olenellina. The University of Kansas Paleontological Contributions, n.s., 3:1–35.Google Scholar
Palmer, A. R., and Rowell, A. J. 1995. Early Cambrian trilobites from the Shackleton Limestone of the Central Transantarctic Mountains. Paleontological Society Memoir, 45:1–28.Google Scholar
Pillola, G. L. 1993. The Lower Cambrian trilobite Bigotina and allied genera. Palaeontology, 36:855–881.Google Scholar
Pocock, K. J. 1964. Estaingia, a new trilobite genus from the Lower Cambrian of South Australia. Palaeontology, 7:458–471.Google Scholar
Pocock, K. J. 1970. The Emuellidae, a new family of trilobites from the Lower Cambrian of South Australia. Palaeontology, 13:522–562.Google Scholar
Pocock, K. J. 1974. A unique case of teratology in trilobite segmentation. Lethaia, 7:63–66.CrossRefGoogle Scholar
Priess, W. V. 1999. Parachilna, South Australia. Explanatory Notes. 1: 250,000 Geological Series Sheet SH54–13. Primary Industries and Resources, South Australia, 52 p.Google Scholar
Ramsköld, L., and Edgecombe, G. D. 1991. Trilobite monophyly revisited. Historical Biology, 4:267–283.CrossRefGoogle Scholar
Rasetti, F. 1972. Cambrian trilobite faunas of Sardinia. Atti della Accademia Nazionale dei Lincei, Memorie, 11:1–100.Google Scholar
Repina, L. N. 1990. Evoliutsiia trilobitov no nachal'nykh etapakh ikh istoricheskogo razvitiia [Evolution of trilobites in their early stages of historical development]. Sibirskoe Otdelenie, Trudy Instituta Geologii i Geofiziki, 764:34–44. (In Russian) Google Scholar
Savitsky, V. E., Evtushenko, V. M., Egorova, L. I., Kontorovitch, A. E., and Shabanov, Yu. Ya. 1972. Cambrian of the Siberian Platform (Yudomia-Olenek section type. Kuonamka assemblage of sediments). Sibirskiy nauchno-issledovatel'skiy institut geologii, geofiziki i mineral'nogo syr'ya Trudy, 130:1–199. (In Russian) Google Scholar
Shu, D. G., Geyer, G., Chen, L., and Zhang, X. L. 1995. Redlichiacean trilobites with preserved soft-parts from the Lower Cambrian Chengjiang Fauna (South China). Beringeria, special issue, 2:203–241.Google Scholar
Šnajdr, M. 1958. Trilobiti českého středního kambria [Trilobites of the Middle Cambrian of Bohemia]. Rozpravy Ústředního Ústavu Geologického, 24:1–280.Google Scholar
Swofford, D. L. 2002. PAUP∗ Phylogenetic Analysis Using Parsimony (∗and Other Methods). Version 4b10. Sinauer Associates, Sunderland, Massachusetts.Google Scholar
Walcott, C. D. 1910. Olenellus and other genera of the Mesonacidae. Smithsonian Miscellaneous Collections, 53:231–422.Google Scholar
Wanner, A. 1901. A new species of Olenellus from the Lower Cambrian of York County, Pennsylvania. Proceedings of the Washington Academy of Sciences, 3:267–272.Google Scholar
Weygoldt, P. 1986. Arthropod interrelationships—The phylogenetic-systematic approach. Zeitschrift für zoologische Systematik und Evolutionsforschung, 24:19–35.Google Scholar
Whitehouse, F. W. 1936. The Cambrian faunas of northeastern Australia. Parts 1 and 2. Memoirs of the Queensland Museum, 11:59–112.Google Scholar
Whittington, H. B. 1957. Ontogeny of Elliptocephala, Paradoxides, Sao, Blainia, and Triarthrus (Trilobita). Journal of Paleontology, 31:934–946.Google Scholar
Whittington, H. B. 1988. Hypostomes and ventral cephalic sutures in Cambrian trilobites. Palaeontology, 31:577–609.Google Scholar
Whittington, H. B. 1989. Olenelloid trilobites: Type species, functional morphology and higher classification. Philosophical Transactions of the Royal Society of London (series B), 324:111–147.Google Scholar
Whittington, H. B. 1990. Articulation and exuviation in Cambrian trilobites. Philosophical Transactions of the Royal Society of London (series B), 329:27–46.Google Scholar
Whittington, H. B. 1997. Morphology of the exoskeleton, p. O1–O85. In Kaesler, R. L. (ed.), Treatise on Invertebrate Paleontology. Pt. O. Arthropoda 1, Trilobita (revised). Geological Society of America and University of Kansas Press, Lawrence.Google Scholar
Whittington, H. B., and Almond, J. E. 1987. Appendages and habits of the Upper Ordovician trilobite Triarthrus eatoni . Philosophical Transactions of the Royal Society of London, series B, 324:111–147.Google Scholar
Whittington, H. B., and Kelly, S. R. A. 1997. Morphological terms applied to Trilobita, p. O313–O329. In Kaesler, R. L. (ed.), Treatise on Invertebrate Paleontology. Pt. O. Arthropoda 1, Trilobita (revised). Geological Society of America and University of Kansas Press, Lawrence.Google Scholar
Zang, W. L., Jago, J. B., and Lin, T. R. 2001. Early Cambrian acritarchs, trilobites and archaeocyaths from Yalkalpo 2, eastern Arrowie Basin, South Australia. Department of Primary Industries and Resources, South Australia, Report Book, 2001/2:–41.Google Scholar
Zenker, J. C. 1833. Beiträge zur Naturgesichte der Urwelt. Oragnische Reste (Petrefacten) aus der Altenbruger Braunkohlen-Formation, dem Blankenburger Quadersandstein, Jenaischen bunten Sandstein und Böhmischen Uebergangsgebirge, Jena, 67 p.Google Scholar
Zhang, W. T. 1957. Cambrian and Ordovician stratigraphy of the Gorge district of the Yangtze, Hupei. Kexue Tongbao, 5:145.Google Scholar
Zhang, W. T. 1962. On the genus Eoredlichia . Acta Palaeontologica Sinica, 10:36–44. (In Chinese with English summary) Google Scholar
Zhang, W. T. 1966. On the classification of Redlichiacea, with description of new families and new genera. Acta Palaeontologica Sinica, 14:135–184. (In Chinese with English summary) Google Scholar
Zhang, W. T. 1987. World's oldest Cambrian trilobites from eastern Yunnan, p. 1–16. In Nanjing Institute of Geology and Palaeontology, Academia Sinica (ed.), Stratigraphy and Palaeontology of Systemic Boundaries in China. Precambrian–Cambrian Boundary, 1. Anhui Science and Technology Publishing House.Google Scholar
Zhang, W. T. 1992. Classification and phylogeny of Redlichioidea (Trilobita). Progress in Geology of China (1989–1992), Papers to the 29th International Geological Congress. Science Press, Beijing, p. 291–296.Google Scholar
Zhang, W. T., Repina, L. N., and Geyer, G. 1997. Suborder Redlichiina Richter, 1932, p. O429–O481. In Kaesler, R. L. (ed.), Treatise on Invertebrate Paleontology. Pt. O. Arthropoda 1, Trilobita (revised). Geological Society of America and University of Kansas Press, Lawrence.Google Scholar
Zhang, W. T., Babcock, L. E., Xiang, L. W., Sun, W. G., Luo, H. L., and Jiang, Z. W. 2001. Lower Cambrian stratigraphy of Chengjiang, eastern Yunnan, China, with special notes on Chinese Parabadiella, Moroccan Abadiella and Australian Abadiella huoi . Acta Palaeontologica Sinica, 40:294–309.Google Scholar
Zhang, W. T., Lu, Y. H., Zhu, Z. L., Qian, Y. Y., Lin, H. L., Zhou, Z. Y., Zhang, S. G., and Yuan, J. L. 1980. Cambrian trilobite faunas of southwestern China. Palaeontologica Sinica, 159:1–497. (In Chinese with English summary) Google Scholar
Zhang, X. G., and Pratt, B. R. 1999. Early Cambrian trilobite larvae and ontogeny of Ichangia ichangensis Chang, 1957 (Protolenidae) from Henan, China. Journal of Paleontology, 73:117–128.CrossRefGoogle Scholar