!"#$ %&'%( )*+'*'&&'(,', -.---'/( ! " #$%%&&&'&& $ ($ $)*$ + , $) -.)%&&)*$ $ $ ) - ) /0)0& ) )1234/56467706//%868) - && 7&& 9 $ :. , ; $9 $! + )*$ $$21$ . +$ 6 < ) # . $ $ $ +$$ +$ 6 $ $ $ $ $< $ + )= $ $ $$$ $ )*$ $ !+$ $ +$ $ ! $ )= + + $21$ $ + $ $ $ $ + $ $$) 3+ $$ 21$ ! + +$ 6 $ $$ $ $ $+$ ) $ $ $ +$ + $ < )*+ + $ $ $ $ ) - $ $ $ $$ >+6 $$ $+$ $ $ 6 $ )*$$ $$ $ $. $ +! +$ ) $ + $ $$ +! +$$ 6!)*$ $ $2 1$ $ + ! + ) $ $ $.$ 9 .$ < $21$)* $1( 3 $? ) ! + +$$ $ $$ 6 $ $ )*$$ + $$ . +$$ $ $$ ) !" # . 21$ $% & %' %($)*% %&+,-./* %" @- .)%&& 11376%0 1234/56467706//%868 ' ''' 60&%A$ 'BB )!)B C D ' ''' 60&%E To my family List of Papers This thesis is based on the following papers, which are referred to in the text by their Roman numerals. I Daley, A.C., Budd, G.E., Caron, J.-B., Edgecombe, G.D. & Collins, D. 2009. The Burgess Shale anomalocaridid Hurdia and its significance for early euarthropod evolution. Science, 323:1597-1600. II Daley, A.C. & Budd, G.E. New anomalocaridid appendages from the Burgess Shale, Canada. In press. Palaeontology. III Daley, A.C., Budd, G.E. and Caron, J.-B. The morphology and systematics of the anomalocaridid Hurdia from the Burgess Shale. Manuscript to be submitted to Journal of Systematic Pa- leontology. IV Daley, A.C. & Peel, J.S. A possible anomalocaridid from the Cambrian Sirius Passet Lagerstätte, North Greenland. In press. Journal of Paleontology. V Budd, G.E. & Daley, A.C. The lobes and lobopods of Opabinia regalis. Submitted to Lethaia. Additionally, the following papers were prepared during the course of my PhD studies, but are not included in the thesis: VI Daley, A.C. 2008. Statistical analysis of mixed-motive shell borings in Ordovician, Silurian and Devonian brachiopods from northern and eastern Canada. Canadian Journal of Earth Sci- ences, 45:213-229. VII Fischer, A.H.L., Arboleda, E., Egger, B., Hilbrant, M., McGregor, A.P., Cole, A.G., and Daley, A.C. 2009. ZOONET: Perspectives on the Evolution of Animal Form. Meeting Report. Journal of Experimental Zoology, Molecular and Developmen- tal Evolution, 312B:679-685. VIII Caron, J.-B., Gaines, R.R., Mángano, G.M., Streng, M. and Daley, A.C. A new Burgess Shale-type assemblage from the “thin” Stephen Formation of the Southern Canadian Rockies. Submitted to Geology. Reprinting and publication is made with permission from the respective copyright holders. Paper I, © The American Association for the Advancement of Science. Papers II, III, IV, V are copyright of the authors. Statement of authorship Paper I: A.C.D collected data, prepared figures, wrote the manuscript to- gether with G.E.B., and ran the phylogenetic analysis with G.D.E. and G.E.B. Fossil material and assemblages were collected, prepared and identi- fied by D.C., and J.B.C. also prepared some specimens. All authors contrib- uted to the interpretation of the fossils and commented on the manuscript. Paper II: A.C.D. collected data, prepared figures, and wrote the manuscript. Both authors contributed to the interpretation of fossil material, and G.E.B commented on the manuscript. Paper III: A.C.D. collected data, ran the statistical analyses, contributed to the interpretation, and prepared figures. All authors contributed to the inter- pretation of the fossils and wrote the manuscript. Paper IV: A.C.D. prepared the figures and wrote the manuscript. J.S.P. col- lected, prepared and photographed the specimens. Both authors contributed to the fossil interpretation, and J.S.P. commented on the manuscript. Paper V: A.C.D. prepared the figures. Both authors photographed the speci- mens, contributed to the fossil interpretation and wrote the manuscript. Disclaimer The papers presented here are for the purpose of public examination as a doctoral thesis only. They are not deemed valid for taxonomic or nomencla- tural purposes [see article 8.2 in the International Code of Zoological No- menclature 4th Edition, edited by Ride et al. (2000)]. Accordingly, all new taxonomic names and emendations in paper III are void. Authority for taxo- nomic work in papers I, II and IV is retained by the original publications. Front cover: Reconstruction of Hurdia by Marianne Collins, 2008 ©ROM/J.-B. Caron. Used with permission. Contents Introduction ..................................................................................................... 9 The early evolution of animal life .............................................................. 9 Euarthropod stem lineage ......................................................................... 11 The anomalocaridids ..................................................................................... 14 History of description from the Burgess Shale......................................... 14 The Burgess Shale anomalocaridid Hurdia victoria ............................ 18 Diversity and global distribution of the anomalocaridids ........................ 20 Anomalocaridid diversity at the Burgess Shale ................................... 20 A possible anomalocaridid from Sirius Passet, Greenland .................. 22 The lobes and lobopods of Opabinia ............................................................ 24 Conclusions and future perspectives ............................................................. 28 Svensk sammanfattning ................................................................................ 29 Hurdia victoria från Burgess Shale .......................................................... 29 Diversitet och spridning av anomalocarider ............................................. 30 Morfologin hos Opabinia regalis ............................................................. 31 Acknowledgements ....................................................................................... 32 References ..................................................................................................... 34 Introduction The early evolution of animal life The evolution of animal life extends back over half a billion years to a time when a major evolutionary radiation, the “Cambrian Explosion”, gave rise to nearly all of the major animal phyla known today (Conway Morris, 1989a; Budd, 2003). Occurring between about 600 and 500 million years ago, this radiation is exquisitely recorded by various fossil lagerstätten, where excep- tional preservation of soft-bodied animals provides a glimpse of complex marine ecosystems during the earliest evolution of modern animal life (Conway Morris, 1989b). Many Cambrian fossils are bizarre and enigmatic forms quite unlike their modern descendants, often inciting lively debate over their morphology, affinity and evolutionary significance. One such group of animals is the anomalocaridids, large presumed predators with a complicated history of description. The following thesis presents research on the morphology, systematics and evolutionary significance of the anomalo- caridids and the closely related Opabinia regalis. Most of the fossils studied herein come from the Burgess Shale in the Ca- nadian Rocky Mountains, the most famous of all Cambrian lagerstätten. Since its discovery by Charles D. Walcott in 1909, the Burgess Shale has produced thousands of exceptionally preserved fossils of soft-bodied organ- isms representing most major animal groups. The main sites are located on Fossil Ridge and Mount Stephen, near the small town of Field, British Co- lumbia (Fig. 1A). The Burgess Shale Formation is a series of basinal cal- careous argillaceous rocks of latest Glossopleura to early Bathyriscus- Elrathina zonal age that has been divided into 10 members (Fig. 1B), most of which have produced fossils (Fletcher and Collins, 1998). The exact pa- leoenvironment and mode of preservation of the Burgess Shale is controver- sial. Some theories suggest that organisms were living along the Cathedral Escarpment, and were transported to deeper water environments by mud- flows (Conway Morris, 1979, 1986), while others argue that most organisms lived, died, and decayed in the same local environment where they were deposited and rapidly buried by mudflows (Caron and Jackson, 2006), pos- sibly in close proximity to mud mounds and brine seeps in some localities other than those on Fossil Ridge (Collom et al., 2009; Johnson et al., 2009). The mode of preservation of Burgess Shale-type fossils involved the sup- 9 pression of organic degradation in the marine environment (Gaines et al., 2008), perhaps by rapid occlusion of sediment porosity soon after deposition (Gaines et al., 2005), or through complex chemical reactions in the sediment, such as clay-organic interactions (Butterfield, 1995) or adsorption of Fe3+ onto biopolymers (Petrovich, 2001). Early authigenic mineral replacement (Orr et al., 1998) and/or late diagenetic aluminosilicate mineral emplacement (Butterfield et al., 2007) also preserve certain anatomical features of some specimens. The main collections of Burgess Shale material include the origi- nal specimens collected by Walcott between the years 19091917, deposited at the Smithsonian National Museum of Natural History (USNM) in Wash-