Sarotrocercus oblitus - Small arthropod with great impact on the understanding of arthropod evolution?

 

Authors: Haug JT, Maas A, Haug C, Waloszek D

Published in: Bulletin of Geosciences, volume 86, issue 4; pages: 725 - 736; Received 16 May 2011; Accepted in revised form 5 September 2011; Online 1 November 2011

Keywords: Burgess Shale, Cambrian, Arthropoda sensu stricto, Euarthropoda, ontogeny,

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Abstract

Sarotrocercus oblitus is a small arthropod from the Cambrian Burgess Shale. It was originally described with a short head with only two appendage-bearing segments (the first appendage being limb-shaped), a short trunk of nine segments and lamellate trunk limbs. This rather “unusual” morphology inspired various authors to propose evolutionary scenarios concerning segmentation and appendages. The head of S. oblitus served also for scenarios about the evolution of the arthropod head, because it seemed to document the evolutionary step between the level of Arthropoda sensu stricto (head with one appendage-bearing segment) and that of Euarthropoda (head comprising four appendage-bearing segments). Here we report that the morphology of S. oblitus differs in several significant aspects from its original description, e.g., in the composition of the head, number of trunk segments, and appendage morphology. In consequence, many earlier assumptions based on the original description must be rejected. Although the material consists of only seven individuals, ontogenetic variation of the number of trunk segments was observed, pointing to, at least, two developmental stages. Therefore, S. oblitus is morphologically less different from other Cambrian arthropods than previously thought, but possesses a head with three appendage-bearing segments and lacks a prominent antenn(ul)a. These characters point to a position of S. oblitus inside Arthropoda s. str., deriving from the lineage towards Euarthropoda. The morphology also indicates a special life style, e.g., by the presence of large, stalked eyes, apparently in convergence to one of the Cambrian “Orsten” crustacean stem-lineage derivatives, Henningsmoenicaris scutula.

References

Barnes, R.S.K., Calow, P., Olive, P.J.W., Golding, D.W. & Spicer, J.I. 2001. The Invertebrates - A Synthesis. Third Edition. 505 pp. Blackwell Science Ltd. Malden, Oxford, Melbourne, Berlin.

Barton, N.H., Briggs, D.E.G., Eisen, J.A., Goldstein, D.B. & Patel, N.H. 2007. Evolution. 834 pp. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York. Bengtson, S. 2000. Teasing fossils out of shales with cameras and computers. Palaeontologia Electronica 3(1), art. 4, 14 pp., http://palaeo-electronica.org/2000_1/fossils/issue1_00.htm.

Boxshall, G.A. 2004. The evolution of arthropod limbs. Biological Reviews 79, 253-300. View article

Briggs, D.E.G. 1978. The morphology, mode of life, and affinities of Canadaspis perfecta (Crustacea: Phyllocarida), Middle Cambrian, Burgess Shale, British Columbia. Philosophical Transactions of the Royal Society of London B 281, 439-487. View article

Briggs, D.E.G. & Collins, D. 1999. The arthropod Alalcomenaeus cambricus Simonetta, from the Middle Cambrian Burgess Shale of British Columbia. Palaeontology 42(1), 953-977. View article

Briggs, D.E.G., Erwin, D.H.&Collier, F.J. 1994. The Fossils of the Burgess Shale. 238 pp. Smithsonian Institution Press, Washington, London.

Briggs, D.E.G. & Fortey, R.A. 1992. The Early Cambrian radiation of arthropods, 335-373. In Lipps, J.H. & Signor, P.W. (eds) Origin and Early Evolution of the Metazoa. Plenum Press, New York.

Budd, G.E. 2001. Ecology of nontrilobite arthropods and lobopods in the Cambrian, 404-427. In Zhuravlev, A.Y. & Riding, R. (eds) Ecology of the Cambrian Radiation. Columbia University Press, New York.

Budd, G.E. 2008. Head structure in upper stem-group euarthropods. Palaeontology 51(3), 561-573. View article

Burzin, M.B., Debrenne, F. & Zhuravlev, A.Y. 2001. Evolution of shallow-water level-bottom communities, 217-237. In Zhuravlev, A.Y. & Riding, R. (eds) Ecology of the Cambrian Radiation. Columbia University Press, New York.

Caron, J.-B. & Jackson, D.A. 2008. Paleoecology of the Greater Phyllopod Bed community, Burgess Shale. Palaeogeography, Palaeoclimatology, Palaeoecology 258(3), 222-256. View article

Castellani, C., Haug, J.T., Haug, C., Maas, A., Schoenemann, B. & Waloszek, D. accepted. Exceptionally well-preserved isolated eyes from late Cambrian ‘Orsten’ faunal assemblages of Sweden. Palaeontology.

Chen, J.-Y., Waloszek, D. & Maas, A. 2004. A new ‘great-appendage’ arthropod from the Lower Cambrian of China and homology of chelicerate chelicerae and raptorial antero-ventral appendages. Lethaia 37, 3-20. View article

Cotton, T.J. & Braddy, S.J. 2004. The phylogeny of arachnomorph arthropods and the origin of Chelicerata. Transactions of the Royal Society of Edinburgh: Earth Sciences 94, 169-193.

Delle Cave, L., Insom, E. & Simonetta, A.M. 1998. Advances, diversions, possible relapses and additional problems in understanding the early evolution of the Articulata. Italian Journal of Zoology 65, 19-38. View article

Dewel, R.A.&Dewel, W.C. 1998. The place of tardigrades in arthropod evolution, 109-124. In Fortey, R.A. & Thomas, R.H. (eds) Arthropod Relationships. The Systematics Association Special Volume Series 55. Chapman & Hall, London.

Fryer, G. 1998. A defence of arthropod polyphyly, 23-34. In Fortey, R.A. & Thomas, R.H. (eds) Arthropod Relationships. The Systematics Association Special Volume Series 55. Chapman & Hall, London.

Fryer, G. 1999. Cambrian animals: evolutionary curiosities or the crucible of creation? Hydrobiologia 403, 1-11. View article

Gould, S.J. 1991a. Zufall Mensch. 391 pp. Carl Hanser Verlag, München, Wien. [English original 1989. Wonderful Life: The Burgess Shale and the Nature of History. W.W. Norton, New York]

Gould, S.J. 1991b. The Disparity of the Burgess Shale arthropod fauna and the limits of cladistic analysis: why we must strive to quantify morphospace. Paleobiology 17(4), 411-423. View article

Gould, S.J. 1994. The evolution of life on Earth. Scientific American, 1994(October), 92-100.

Gould, S.J. 1999. The evolution of life, 1-14. In Schopf, J.W. (ed.) Evolution! Facts and Fallacies. Academic Press, San Diego.

Haug, J.T., Maas, A. & Waloszek, D. 2009. Ontogeny of two Cambrian stem crustaceans, †Goticaris longispinosa and †Cambropachycope clarksoni. Palaeontographica, Abteilung A 289, 1-43.

Haug, J.T., Maas, A. & Waloszek, D. 2010. †Henningsmoenicaris scutula, †Sandtorpia vestrogothiensis gen. et sp. nov. and heterochronic events in early crustacean evolution. Earth and Environmental Science Transactions of the Royal Society of Edinburgh 100, 311-350. View article

Haug, J.T., Maas, A., Haug, C. & Waloszek, D. accepted a. Chapter 2: Evolution of Crustacean Appendages. In Watling, L. & Thiel, M. (eds) The Natural History of the Crustacea. Volume 1: Functional Morphology and Diversity. Oxford University Press.

Haug, J.T., Waloszek, D., Maas, A., Liu, Y. & Haug, C. accepted b. Functional morphology, ontogeny and evolution of mantis shrimp-like predators in the Cambrian. Palaeontology.

Hou, X. 1987. Two new arthropods from Lower Cambrian Chengjiang, Eastern Yunnan. Acta Palaeontologica Sinica 26, 236-256.

Hou, X. & Bergström, J. 1997. Arthropods of the Lower Cambrian Chengjiang fauna, southwest China. Fossils and Strata 45, 1-116.

Lin, J. 2009. Function and hydrostatics in the telson of the Burgess Shale arthropod Burgessia. Biology Letters 5(3), 376-379. View article

Liu, Y., Hou, X. & Bergström, J. 2007. Chengjiang arthropod Leanchoilia illecebrosa (Hou, 1987) reconsidered. Geologiska föreningens i Stockholm förhandlingar 129, 263-272. View article

Maas, A., Waloszek, D., Chen, J., Braun, A., Wang, X. & Huang, D. 2004. Phylogeny and life habits of early arthropods - predation in the Early Cambrian sea. Progress in Natural Science 14, 158-166. View article

Minelli, A. 2001. A three-phase model of arthropod segmentation. Development Genes and Evolution 211, 509-521. View article

Müller, K.J. 1983. Crustacea with preserved soft parts from the Upper Cambrian of Sweden. Lethaia 16, 93-109. View article

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

Olesen, J. 2007. Monophyly and phylogeny of Branchiopoda, with focus on morphology and homologies of branchiopod phyllopodous limbs. Journal of Crustacean Biology 27, 165-183. View article

Schoenemann, B., Castellani, C., Clarkson, E.N.K., Haug, J.T., Maas, A., Haug, C. & Waloszek, D. submitted. The sophisticated visual system of a tiny Cambrian crustacean - analysis of a stalked fossil compound eye. Proceedings of the Royal Society of London B.

Scholtz, G. & Edgecombe, G.D. 2006. The evolution of arthropod heads: reconciling morphological, developmental and palaeontological evidence. Development Genes & Evolution 216, 395-415. View article

Schram, F.R. & Koenemann, S. 2001. Developmental genetics and arthropod evolution: part I, on legs. Evolution & Development 3(5), 343-354. View article

Selfa, J. & Pujade-Villar, J. 2002. Fonaments de zoologia dels artropodes. 426 pp. Universitat de Valencia, Valencia.

Simonetta, A.M. & Delle Cave, L. 1975. The Cambrian non Trilobite Arthropods from the Burgess Shale of British Columbia. A study of their comparative taxonomy and evolutionary significance. Palaeontographica Italica 69, 1-37.

Stein, M. 2010. A new arthropod from the Early Cambrian of North Greenland, with a ‘great appendage’-like antennula. Zoological Journal of the Linnean Society 158, 477-500. View article

Stein, M., Waloszek, D., Maas, A., Haug. J.T. & Müller, K.J. 2008. Oelandocaris oelandica revisited. Acta Palaeontologica Polonica 53, 461-484.View article

Sutton, M.D., Briggs, D.E.G., Siveter, D.J., Siveter, D.J. & Orr, P.J. 2002. The arthropod Offacolus kingi (Chelicerata) from the Silurian of Herefordshire, England: computer based morphological reconstructions and phylogenetic affinities. Proceedings of the Royal Society of London B 269, 1195-1203. View article

Van Roy, P. 2006. An aglaspidid arthropod from the Upper Ordovician of Morocco with remarks on the affinities and limitations of Aglaspidida. Transactions of the Royal Society of Edinburgh Earth Sciences 96, 327-350.

Wahlenberg, G. 1818. Petrificata telluris svecanae. Nova Acta Regiae Societatis Scientiarum Upsaliensis 8, 1-116.

Walcott, C.D. 1912. Middle Cambrian Branchiopoda, Malacostraca, Trilobita and Merostomata. Cambrian Geology and Paleontology II. Smithsonian Miscellaneous Collections 57, 145-228.

Walossek, D. 1999. On the Cambrian diversity of Crustacea. Pages 3-27. In Schram, F.R. & Vaupel Klein, J.C. von (eds) Crustaceans and the Biodiversity Crisis, Proceedings of the Fourth International Crustacean Congress, Amsterdam, The Netherlands, July 20-24, 1998, vol. 1. Brill Academic Publishers, Leiden, The Netherlands.

Walossek, D. & Müller, K.J. 1990. Upper Cambrian stem-lineage crustaceans and their bearing upon the monophyletic origin of Crustacea and the position of Agnostus. Lethaia 23, 409-427. View article

Waloszek, D., Chen, J.,Maas, A.&Wang, X. 2005. Early Cambrian arthropods-new insights into arthropod head and structural evolution. Arthropod Structure and Development 34, 189-205. View article

Waloszek, D., Maas, A., Chen, J.-Y. & Stein, M. 2007. Evolution of cephalic feeding structures and the phylogeny of Arthropoda. Palaeogeography, Palaeoclimatology, Palaeoecology 254, 273-287. View article

Whittington, H.B. 1974. Yohoia Walcott and Plenocaris n. gen., arthropods from the Burgess Shale, Middle Cambrian, British Columbia. Geological Survey of Canada, Bulletin 231, 1-63.

Whittington, H.B. 1981. Rare Arthropods from the Burgess Shale, Middle Cambrian, British Columbia. Philosophical Transactions of the Royal Society of London, Series B, Biological Sciences 292(1060), 329-357.View article

Wills, M.A., Briggs, D.E.G. & Fortey, R.A. 1994. Disparity as an Evolutionary Index: A Comparison of Cambrian and Recent Arthropods. Paleobiology 20(2), 93-130. View article

Wills, M.A., Briggs, D.E.G., Fortey, R.A. & Wilkinson, M. 1995. The significance of fossils in understanding arthropod evolution. Verhandlungen der Deutschen Zoologischen Gesellschaft 88, 203-215.

Wills, M.A., Briggs, D.E.G. & Fortey, R.A. 1998. Evolutionary correlates of arthropod tagmosis: scrambled legs, 57-66. In Fortey, R.A. & Thomas, R.H. (eds) Arthropod Relationships. The Systematics Association Special Volume Series 55. Chapman & Hall, London.