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Axial growth gradients across the postprotaspid ontogeny of the Silurian trilobite Aulacopleura koninckii

  • Giuseppe Fusco (a1), Paul S. Hong (a2) and Nigel C. Hughes (a3)


Recent morphometric analysis revealed a juvenile (meraspid) axial growth gradient in the trunk of the ~429 Myr old trilobite Aulacopleura koninckii that resulted from growth control based on positional specification, as is common among extant organisms. Here we explore axial growth gradients in the more anterior body region, the cephalon, and in the cephalon and trunk during subsequent development in the holaspid period. We detected an axial growth gradient in the cephalon in the meraspid period, flatter and opposite in direction to that of the trunk, which also persisted during the holaspid period. We also found an holaspid trunk growth gradient, with a different distribution of growth rates among segments than that of the meraspid period. These newly observed growth gradients are compatible with the mechanism of growth control inferred for the meraspid trunk. Thus, the same kind of growth control may have operated in both body regions and during the whole ontogeny of A. koninckii. This study, along with others on the same species that preceded it, show that morphometric analysis of appropriate data sets can address questions of high interest for evolutionary developmental biology using data from fossils. By revealing developmental features at deep nodes of the phylogenetic tree, these studies will elucidate both how developmental processes evolved and how they themselves affected the evolution of organismal body patterning.



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Abràmoff, M. D., Magalhães, P. J., and Ram, S. J.. 2004. Image processing with ImageJ. Biophotonics International 11:3642.
Andersson, G. 1976. Post-embryonic development of Lithobius forticatus (L.), (Chilopoda: Lithobiidae). Entomologica Scandinavica 7:161168.
Bergström, J., and Levi-Setti, R.. 1978. Phenotypic variation in the middle Cambrian trilobite Paradoxides davidis Salter at Manuels, S.E. Newfoundland. Geologica et Palaeontologica 12:140.
Bortolin, F., Benna, C., and Fusco, G.. 2011. Gene expression during post-embryonic segmentation in the centipede Lithobius peregrinus (Chilopoda, Lithobiomorpha). Development Genes and Evolution 221:105111.
Chatterton, B. D. E., and Speyer, S. E.. 1997. Ontogeny. Pp. O173–O247 in H. B. Whittington et al. Arthropoda 1, Trilobita, Vol. 1, Introduction, order Agnostida, order Redlichiida. Part O of R. L. Kaesler, ed. Treatise on invertebrate paleontology. Geological Society of America, Boulder, Colo., and University of Kansas, Lawrence.
Cock, A. G. 1966. Genetical aspects of metrical growth and form in animals. Quarterly Review of Biology 41:131190.
Dai, T., and Zhang, X.-L.. 2013. Morphology and ontogeny of the eodiscoid trilobite Sinodiscus changyangensis from the lower Cambrian of South China. Palaeontology 56:411420.
Dai, T., Zhang, X.-L, and Peng, S.-C.. 2014. Morphology and ontogeny of Hunanocephalus ovalis (trilobite) from the Cambrian of South China. Gondwana Research 25:991998.
Fusco, G. 2005. Trunk segment numbers and sequential segmentation in myriapods. Evolution and Development 7:608617.
Fusco, G., and Minelli, A.. 2013. Arthropod segmentation and tagmosis. Pp. 197221in A. Minelli, G. Boxshall, and G. Fusco, eds. Arthropod biology and evolution: molecules, development, morphology. Springer, Berlin.
Fusco, G., Hughes, N. C., Webster, M., and Minelli, A.. 2004. Exploring developmental modes in a fossil arthropod: growth and trunk segmentation of the trilobite Aulacopleura koninckii. American Naturalist 163:167183.
Fusco, G., Garland, T. Jr., Hunt, E., and Hughes, N. C.. 2012. Developmental trait evolution in trilobites. Evolution 66:314329.
Fusco, G., Hong, P. S., and Hughes, N. C.. 2014. Positional specification in the segmental growth pattern of an early arthropod. Proceedings of the Royal Society of London B 281:20133037.
Hong, P. S., Hughes, N. C., and Sheets, H. D.. 2014. Size, shape, and systematics of the Silurian trilobite Aulacopleura koninckii. Journal of Paleontology 88:11201138.
Hou, J.-B., Hughes, N. C., Lan, T., Yang, J., and Zhang, X.-G.. 2015. Early postembryonic to mature ontogeny of the oryctocephalid trilobite Duodingia duodingensis from the lower Cambrian (Series 2) of southern China. Papers in Palaeontology 1:497513.
Hughes, N. C. 2003. Trilobite body patterning and the evolution of arthropod tagmosis. BioEssays 25:386395.
Hughes, N. C. 2007. The evolution of trilobite body patterning. Annual Review of Earth and Planetary Sciences 35:401434.
Hughes, N. C., Minelli, A., and Fusco, G.. 2006. The ontogeny of trilobite segmentation: a comparative approach. Paleobiology 32:602627.
Hughes, N. C., Kříž, J., Macquaker, J. H. S., and Huff, W. D.. 2014. The depositional environment and taphonomy of the Homerian “Aulacopleura shales” fossil assemblage near Loděnice, Czech Republic (Prague Basin, Perunican microcontinent). Bulletin of Geosciences 89:219238.
Iatrou, G. D., and Stamou, G. P.. 1988. Post-embryonic growth of Glomeris balcanica (Diplopoda: Glomeridae). Pedobiologia 32:343353.
Kihm, J.-H., Park, T.-Y., and Choi, D.-K.. 2013. Ontogeny of the ptychaspidid trilobite Quadraticephalus elongatus Kobayashi, 1935 from the Furongian (late Cambrian) Hwajeol Formation, Korea. Journal of Paleontology 87:379390.
Minelli, A., and Fusco, G.. 2013. Arthropod post-embryonic development. Pp. 91122in A. Minelli, G. Boxshall, and G. Fusco, eds. Arthropod biology and evolution: molecules, development, morphology. Springer, Berlin.
Minelli, A., Fusco, G., and Hughes, N. C.. 2003. Tagmata and segment specification in trilobites. Special Papers in Palaeontology 70:3143.
Moczek, A. P., Sears, K. E., Stollewerk, A., Wittkopp, P. J., Diggle, P., Dworkin, I., Ledon-Rettig, C., Matus, D. Q., Roth, S., Abouheif, E., Brown, F. D., Chiu, C.-H., Cohen, C. S., De Tomaso, A. W., Gilbert, S. F., Hall, B., Love, A. C., Lyons, D. C., Sanger, T. J., Smith, J., Specht, C., Vallejo-Marin, M., and Extavour, C. G.. 2015. The significance and scope of evolutionary developmental biology: a vision for the 21st century. Evolution and Development 17:198219.
Müller, G. B. 2007. Evo–devo: extending the evolutionary synthesis. Nature Reviews Genetics 8:943949.
Ramsköld, L. 1991. Pattern and process in the evolution of the Odontopleuridae (Trilolita). The Selenopeltinae and Ceratocephalinae. Transactions of the Royal Society of Edinburgh (Earth Sciences) 82:143181.
Ramsköld, L., and Chatterton, B. D. E.. 1991. Revision and subdivision of the polyphyletic “Leonaspis” (Trilobita). Transactions of the Royal Society of Edinburgh (Earth Sciences) 82:333371.
Sánchez, M. 2012. Embryos in deep time. University of California Press, Berkeley.
Webster, M. 2015. Ontogeny and intraspecific variation of the early Cambrian trilobite Olenellus gilberti, with implications for olenelline phylogeny and evolutionary trends in phenotypic variation. Journal of Systematic Palaeontology 13:174.
Yuan, W.-W., Li, L.-Z., Zhou, Z.-Y., and Zhang, C.-S.. 2001. Ontogeny of the Silurian trilobite Aulacopleura (Aulacopleura) wulongensis Wang of western Hubei and its implications for the phylogeny of the Aulacopleurinae. Acta Palaeontologica Sinica 40:388398.


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