Skip to main content Accessibility help

Ontogeny of the two co-occurring middle Furongian (late Cambrian) shumardiid trilobites and the protaspid morphology of shumardiids

  • TAE-YOON S. PARK (a1)


Shumardiid trilobites had a small, unique morphology, and formed a key constituent in trilobite faunas during the Cambrian–Ordovician. Because of their unusual morphology, they have been the subject of research s, into various aspects such as their life habit, functional morphology, evolutionary origin and ontogeny. Originally, a flat, adult-like protaspid morphology was suggested for shumardiids, but subsequently a bulbous protaspid morphology interpreted to be associated with metamorphosis was also suggested for this unique trilobite group. This article documents the ontogeny of the two co-occurring shumardiid trilobites, Akoldinioidia latus Park and Kihm and Koldinioidia choii Park and Kihm, from the middle Furongian Hwajeol Formation, Taebaeksan Basin, Korea. Interestingly, protaspides of the two shumardiids have a bulbous morphology. Given the stratigraphic occurrences of the two shumardiids, it can be inferred that commutavi protaspis appeared quite early in the shumardiid evolution. The co-occurrence of the two closely related trilobites is reminiscent of sexual dimorphism, although further evidence is required to prove it. The appearance of metamorphosis-undergoing protaspides in the Furongian shumardiids may have been due to the onset of increasing ecological pressure in the early phase of the Great Ordovician Biodiversification Event.


Corresponding author

*Author for correspondence:


Hide All
Adrain, J. M. 2011. Class trilobita walch, 1771. In Animal Biodiversity: An Outline of Higher-Level Classification and Survey of Taxonomic Richness (ed. Zhang, Z.-Q.). Zootaxa 3148, 104–9.
Adrain, J. M., Fortey, R. A. & Westrop, S. R. 1998. Post-Cambrian trilobite diversity and evolutionary faunas. Science 280, 1922–5.
Benedetto, J. L., Caňas, F. L. & Astini, R. A. 1986. Braquiópodos y trilobites de la zona de transición entre las Formaciones San Juan y Gualcamayo en el área de Guandacol (La Rioja, Argentina). IV Congreso Argentino de Paleontología y Bioestratigrafía, Mendoza 1, 31–44.
Callaway, C. 1877. On a new area of Upper Cambrian rocks in South Shropshire, with a description of a new fauna. Quarterly Journal of the Geological Society of London 33, 652–72.
Cederström, P., Ahlberg, P., Nilsson, C. H., Ahlgren, J. & Eriksson, M. E. 2011. Moulting, ontogeny and sexual dimorphism in the Cambrian ptychopariid trilobite Strenuaeva inflata from the northern Swedish Caledonides. Palaeontology 54, 685703.
Chatterton, B. D. E. & Speyer, S. E. 1997. Ontogeny. In Treatise on Invertebrate Paleontology, Part O, Trilobita 1, Revised (ed. Kaesler, R. L.), pp. 173247. Boulder, CO: Geological Society of America and University of Kansas Press.
Choi, D. K., Chough, S. K., Kwon, Y. K., Lee, S.-B., Woo, J., Kang, I., Lee, H. S., Lee, S. M., Sohn, J. W., Shinn, Y. J. & Lee, D.-J. 2004. Taebaek Group (Cambrian–Ordovician) in the Seokgaejae section, Taebaeksan Basin: a refined lower Paleozoic stratigraphy in Korea. Geosciences Journal 8, 125–51.
Dai, T. & Zhang, X. 2011. Ontogeny of the eodiscoid trilobite Tsunyidiscus acutus from the Lower Cambrian of South China. Palaeontology 54, 1279–88.
Dai, T. & Zhang, X. 2013. Morphology and ontogeny of the eodiscoid trilobite Sinodiscus changyangensis from the Lower Cambrian of South China. Palaeontology 56, 411–20.
Dai, T., Zhang, X. & Peng, S. 2014. Morphology and ontogeny of Hunanocephalus ovalis (trilobite) from the Cambrian of South China. Gondwana Research 25, 991–8.
Dai, T., Zhang, X. & Peng, S. 2016. Morphology and development of the eodiscoid trilobite Tsunyidiscus yanjiazhaiensis from the Cambrian (Stage 3, Series 2) of South China. Journal of Systematic Palaeontology 14, 7589.
Endo, R. 1944. Restudies on the Cambrian Formations and Fossils in Southern Manchoukou. Bulletin of Central National Museum of Manchoukou 7, 1100 (in Japanese).
Fortey, R. A. & Hughes, N. C. 1998. Brood pouches in trilobites. Journal of Paleontology 72, 638–49.
Fortey, R. A. & Owens, R. M. 1991. A trilobite fauna from the highest Shineton Shales in Shropshire, and the correlation of the latest Tremadoc. Geological Magazine 128, 437–64.
Fortey, R. A. & Rushton, A. W. A. 1980. Acanthopleurella Groom 1902: origin and life-habits of a miniature trilobite. Bulletin of British Museum of Natural History 33, 7989.
Fusco, G., Garland, T. Jr, Hunt, G. & Hughes, N. C. 2012. Developmental trait evolution in trilobites. Evolution 66, 314–29.
Groom, T. T. 1902. On a new trilobite from the Dictyonema-shales of the Malvern Hills. Geological Magazine 9, 70–3.
Harper, D. A. T., Zhan, R.-B. & Jin, J. 2015. The Great Ordovician Biodiversification Event: reviewing two decades of research on diversity's big bang illustrated by mainly brachiopod data. Palaeoworld 24, 7585.
Hughes, N. C. & Fortey, R. A. 1995. Sexual dimorphism in trilobites, with an Ordovician case study. In Ordovician Odyssey (eds Cooper, J. C., Droser, M. L. & Finney, S. C.), pp. 419–21. Los Angeles: SEPM Pacific Section.
Hughes, N. C., Minelli, A. & Fusco, G. 2006. The ontogeny of trilobite segmentation: a comparative approach. Paleobiology 32, 602–27.
Jell, P. A. & Adrain, J. M. 2003. Available generic names for trilobites. Memoirs of the Queensland Museum 48, 331551.
Kihm, J.-H, Park, T.-Y. & Choi, D. K. 2013. Ontogeny of the ptychaspidid trilobite Quadraticephalus elongatus Kobayashi, 1935 from the Furongian (late Cambrian) Hwajeol Formation, Korea. Journal of Paleontology 87, 379–90.
Knell, J. R. & Fortey, R. A. 2005. Trilobite spines and beetle horns: sexual selection in the Palaeozoic? Biology Letters 1, 196–9.
Kobayashi, T. 1933. Upper Cambrian of the Wuhutsui Basin, Liaotung, with special reference of eastern Asia, and its subdivision. Japanese Journal of Geology and Geography 11, 55155.
Kobayashi, T. 1935. The Cambro-Ordovician formations and faunas of South Chosen. Paleontology, Part III, 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, 49344.
Kwon, Y. K., Chough, S. K., Choi, D. K. & Lee, D. J. 2006. Sequence stratigraphy of the Taebaek Group (Cambrian–Ordovician), mideast Korea. Sedimentary Geology 192, 1955.
Lu, Y.-H. & Qian, Y.-Y. 1983. New zonation and correlation of the upper Cambrian Changshanian Stage in North China. Acta Palaeontologica Sinica 22, 234–54.
Mansuy, H. 1916. Faunes Cambriennes de l'Extrême-Orient méridional. Mémoires du Service Géologique de l'Indochine 5, 144.
Park, T.-Y. & Choi, D. K. 2009. Post-embryonic development of the Furongian (late Cambrian) trilobite Tsinania canens: implications for life mode and phylogeny. Evolution & Development 11, 441–55.
Park, T.-Y. & Choi, D. K. 2010. Ontogeny and ventral median suture of the ptychaspidid trilobite Asioptychaspis subglobosa (Sun, 1924) from the Furongian (Upper Cambrian) Hwajeol Formation, Korea. Journal of Paleontology 84, 309–20.
Park, T.-Y. & Choi, D. K. 2011a. Trilobite faunal successions across the base of the Furongian Series in the Taebaek Group, Taebaeksan Basin, Korea. Geobios 44, 481–98.
Park, T.-Y. & Choi, D. K. 2011b. Ontogeny of the Furongian (late Cambrian) remopleuridioid trilobite Haniwa quadrata Kobayashi, 1933 from Korea: implications for trilobite taxonomy. Geological Magazine 148, 288303.
Park, T.-Y. & Choi, D. K. 2011c. Constraints on using ontogenetic data for trilobite phylogeny. Lethaia 44, 250–4.
Park, T.-Y. & Choi, D. K. 2012a. Middle Furongian (late Cambrian) shumardiids from the Sesong Formation, Taebaek Group, Korea. Journal of Paleontology 86, 51–9.
Park, T.-Y. & Choi, D. K. 2012b. Middle Furongian (late Cambrian) polymerid trilobites from the upper part of the Sesong Formation, Taebaeksan Basin, Korea. Geosciences Journal 16, 381–98.
Park, T.-Y. S. & Kihm, J.-H. 2015a. Furongian (late Cambrian) trilobites from the Asioptychaspis subglobosa Zone of the Hwajeol Formation, Korea. Alcheringa 39, 181–99.
Park, T.-Y. S. & Kihm, J.-H. 2015b. Post-embryonic development of the Early Ordovician (ca. 480 Ma) trilobite Apatokephalus latilimbatus Peng, 1990 and the evolution of metamorphosis. Evolution & Development 17, 289301.
Park, T.-Y. S., Kihm, J.-H., Woo, J., Kim, Y.-H.G. & Lee, J. I. 2016. Ontogeny of the Furongian (late Cambrian) trilobite Proceratopyge cf. P. lata Whitehouse from northern Victoria Land, Antarctica, and the evolution of metamorphosis in trilobites. Palaeontology 59, 657–70.
Park, T.-Y., Moon, S. J., Han, Z. & Choi, D. K. 2008. Ontogeny of the middle Cambrian trilobite Shantungia spinifera Walcott, 1905 from North China and its taxonomic significance. Journal of Paleontology 82, 851–5.
Peng, S.-C. 1992. Upper Cambrian Biostratigraphy and Trilobite Faunas of the Cili-Taoyuan Area, Northwestern Hunan, China. Memoirs of the Association of Australasian Palaeontologists no. 13.
Peng, S.-C., Babcock, L. E., Hughes, N. C. & Lin, H. L. 2003. Upper Cambrian Shumardiids from northwestern Hunan, China. Special Papers in Palaeontology 70, 197212.
Qian, Y. 1994. Trilobites from the middle Upper Cambrian (Changshan Stage) of north and northeast China. Palaeontologica Sinica, New Series B 30, 1176 (in Chinese).
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, 297314.
Stubblefield, C. J. 1926. Notes on the development of a trilobite, Shumardia pusilla (Sars). Linnean Society Journal of Zoology 36, 345–72.
Sun, Y. C. 1924. Contributions to the Cambrian faunas of North China. Palaeontologica Sinica, series B 1, 1109.
Waisfeld, B. G., Vaccari, N. E., Chatterton, B. D. E. & Edgecombe, G. D. 2001. Systematics of Shumardiidae (Trilobita), with new species from the Ordovician of Argentina. Journal of Paleontology 75, 827–59.
Walcott, C. D. 1905. Cambrian faunas of China. Proceedings of the US National Museum 29, 1106.
Whittington, H. B. 1957. The ontogeny of trilobites. Biological Reviews 32, 421–69.
Zhu, X. & Peng, S. 2006. Eoshumardia (Trilobita, Cambrian), a junior synonym of Koldinioidia. Alcheringa 30, 183–9.


Type Description Title
Supplementary materials

Park supplementary material
Park supplementary material 1

 Unknown (15 KB)
15 KB
Supplementary materials

Park supplementary material
Park supplementary material 2

 Unknown (16 KB)
16 KB
Supplementary materials

Park supplementary material
Park supplementary material 3

 Unknown (13 KB)
13 KB
Supplementary materials

Park supplementary material
Park supplementary material 4

 Unknown (16 KB)
16 KB


Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed