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Conway Morris and Caron - A primitive fish from the Cambrian of North America Supplementary information 1) Data table for phylogenetic analysis and detailed results Our phylogenetic analysis is based on a data matrix last revised by Sansom et al.1 Most characters and taxa are from Janvier2, subsequently revised by Donoghue et al.3, Donoghue and Smith4 and Gess et al.5 We have revised the coding of some characters related to Haikouichthys6,7 and added new characters (#110-116) and taxa (Pikaia8, Metasprigginathis paper and 9, and Myllokunmingia6 as well as Hemichordata, the latter is used as the outgroup) relevant to early chordate evolution. Characters (#110 and 115-116) are based on Mallatt and Holland10, and were coded as, or slightly modified from the original designation. We have also added a number of characters specific to the pharyngeal area (#111-114) based on Mallatt11,12. Taxa with less than 25% of applicable characters across all coded characters (i.e. Cornovichthys and Achanarella) were excluded from this analysis. The final matrix has 116 characters and 25 taxa. CHARACTERS (a) Brain, sensory and nervous system 1. Neural crest absent = 0, present = 1 2. Olfactory peduncles absent = 0, present = 1 3. Pineal organ (extra-ocular photoreceptor region expressing pineal opsins)

absent = 0, present = 1 4. Adenohypophysis absent = 0, present = 1 5. Adenohypophysis simple = 0, compartmentalized = 1 6. Optic tectum absent = 0, present = 1 7. Cerebellar primordia absent = 0, present = 1 8. Pretrematic branches in branchial nerves absent = 0, present = 1 9. Flattened spinal cord absent = 0, present = 1 10. Ventral and dorsal spinal nerve roots united, absent = 0, present = 1 11. Mauthner fibres in central nervous system absent = 0, present = 1 12. Retina absent = 0, present = 1 13. Olfactory organ with external opening absent = 0, present = 1 14. Nasohypophyseal opening serving respiration (nasohypophyseal duct)

absent = 0, present = 1 15. Single nasohypophyseal opening, absent = 0, present = 1 16. Position of nasohypophyseal opening: terminal = 0, dorsal = 1 17. Olfactory organ unpaired = 0, paired = 1 18. Extrinsic eye musculature absent = 0, present = 1 19. Otic capsule anterior to branchial series, absent = 0, present = 1 20. Semicircular canals in labyrinth absent = 0, present = 1 21. Vertical semicircular canals forming loops, absent = 0, present = 1

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22. Externally open endolymphatic ducts absent = 0, present = 1 23. Electroreceptive cells absent = 0, present = 1 24. Sensory lines absent = 0, present = 1 25. Sensory-lines on head only = 0, on head plus body = 1 26. Sensory-line enclosed in grooves = 0, enclosed in canals = 1 (b) Mouth and branchial system 27. Pouch-shaped gills absent = 0, present = 1 28. Single confluent branchial opening, absent = 0, present = 1 29. Elongate branchial series: more than 10 gill pouches/slits = 0, fewer than

10 = 1 30. Gill openings lateral and arranged in slanting row, absent = 0, present = 1 31. Position of gill openings: laterally = 0, ventrally = 1 32. Opercular flaps associated with gill openings, absent = 0, present = 1 33. Endodermal gill lamellae, absent = 0, present = 1 34. Gill lamellae with filaments, absent = 0, present = 1 35. Mouth terminal = 0, ventral = 1 36. Oral hood absent = 0, present = 1 37. Velum absent = 0, present = 1 (c) Circulatory system 38. Multi-chamber heart absent = 0, present = 1 39. Closed pericardium absent = 0, present = 1 40. Open blood system absent = 0, present = 1 41. Paired dorsal aortae absent = 0, present = 1 42. Large lateral head vein absent = 0, present = 1 43. Lymphocytes absent = 0, present = 1 44. Subaponeurotic vascular plexus absent = 0, present = 1 (d) Fins and fin-folds 45. Dorsal fin: separate dorsal fin absent = 0, present = 1 46. Dorsal fin originates at posterior of branchial series = 0, restricted to

posterior of trunk and/or caudal region = 1 47. Anal fin separate, absent = 0, present = 1 48. Fin ray supports, absent = 0, present = 1 49. Paired antero-posterior skin folds absent = 0, present = 1 50. Constricted pectoral fins with endoskeletal elements absent = 0, present =

1 51. Pelvic fins/flap, absent = 0, present = 1 52. Tail shape: no distinct lobes developed = 0, ventral lobe much larger than

dorsal = 1, dorsal lobe much larger than ventral = 2, dorsal and ventral lobes almost equally developed = 3

53. Chordal disposition relative to tail development, isochordal = 0, hypochordal = 1, hyperchordal = 2

54. Preanal median fold absent = 0, present = 1 (e) Skeletal 55. Ability to synthesise creatine phosphatase absent = 0, present = 1 56. Visceral arches fused to the neurocranium absent = 0, present =1 57. Keratinous teeth absent = 0, present = 1

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58. Circumoral teeth absent = 0, present = 1 59. Circumoral teeth arranged in radiating series, absent = 0, present = 1 60. Trematic rings absent = 0, present = 1 61. Arcualia absent = 0, present = 1 62. Piston cartilage and apical plate, absent = 0, present = 1 63. Midline retractor muscle and paired protractor muscles, absent = 0,

present = 1 64. Transversely biting teeth (the wording of this character description has

been modified in order reduce ambiguity; coding reflects Gess et al. 2006) , absent = 0, present 1

65. Jaws (dorsoventral bite), absent 0, present = 1 66. Chondroitin 6-sulphate in cartilage, absent = 0, present = 1 67. Braincase with lateral walls, absent = 0, present = 1 68. Neurocranium entirely closed dorsally and covering the brain, absent = 0,

present = 1 69. Occiput enclosing vagus and glossopharyngeal nerves, absent = 0, present

= 1 70. Annular cartilage absent = 0, present = 1 71. Large oral disc absent = 0, present = 1 72. Tentacle cartilages; absent = 0, present = 1 73. Trunk dermal skeleton absent = 0, present = 1 74. Perichondral bone absent = 0, present = 1 75. Calcified cartilage absent = 0, present = 1 76. Cartilage composed of huge clumped chondrocytes, absent = 0, present =

1 77. Calcified dermal skeleton absent = 0, present = 1 78. Lamellar aspidin, absent = 0, present = 1 79. Cellular bone, absent = 0, present = 1 80. Dentine absent = 0, present = 1. Dentinous tissues are preserved in same

deposits as Jamoytius in the thelodont Loganellia, but there is no evidence of dentine in any Jamoytius specimen. Jamoytius can therefore be reliably interpreted as lacking dentine.

81. Dentine present as mesodentine = 0, orthodentine = 1 82. Enamel/oid absent = 0, (monotypic) enamel = 1, enameloid (bitypic

enamel) = 2 83. Three-layered exoskeleton consisting of a basal lamella, middle spongy

(or cancellar) layer and a superficial (often ornamented) layer: absent = 0, present = 1

84. Cancellar layer in exoskeleton, with honeycomb-shaped cavities, absent = 0, present = 1

85. Scales/denticles/teeth composed of odontodes absent = 0, present = 1 86. Scale shape: diamond-shaped = 0, rod-shaped = 1 87. Oak-leaf-shaped tubercles, absent = 0, present = 1 88. Oral plates absent = 0, present = 1 89. Denticles in pharynx absent = 0, present = 1 90. Dermal head covering in adult state absent = 0, present = 1 91. Large unpaired ventral and dorsal dermal plates on head, absent = 0,

present = 1 92. Massive endoskeletal head shield covering the gills dorsally, absent = 0,

present = 1

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93. Sclerotic ossicles absent = 0, present = 1 94. Ossified endoskeletal sclera encapsulating the eye, absent = 0, present = 1 (g) Miscellaneous 95. High blood pressure, absent = 0, present = 1 96. Hyperosmoregulation, absent = 0, present = 1 97. Male gametes shed directly through the coelom, absent = 0, present = 1 98. Forward migration of postotic myomeres, absent = 0, present = 1 99. Larval phase, absent = 0, present = 1 (h) Additional characters due to change in coding strategy and the previous

characters upon which they are contingent 100. (3.) Pineal opening covered = 0, uncovered = 1 101. (13.) External nasal opening single = 0, paired = 1 102. (20.) Number of semicircular canals one = 0, two = 1, three = 2 103. (24.) Neuromasts in sensory liness absent = 0, present = 1 104. (38.) Relative position of atrium and ventricle of heart: well separated = 0,

close to each other = 1 105. (43.) Lymphocytes antigen receptors VLR = 0, T and B = 1 106. (49.) Paired antero-posterior skin folds extend along the trunk = 0,

anterior only =1 107. (61.) Ventral arcualia absent = 0, present = 1 108. (85.) Scales/denticles/teeth made up by single odontode = 0, made up by

several odontodes = 1 109. (90.) Dermal head covering in adult state: micromeric = 0, large

(macromeric) dermal plates or shield = 1 110. Myomeres 0=absent, 1=present-simple, 2=W-shaped (MH#4mod) 111. Pharyngeal bars. 0=continuous, 1=segmented (i.e. with epi and cerato

components), 2=complex framework forming branchial basket or cartilaginous nodules

112. Pharyngeal bars 0=external, 1=internal 113. Mandibular branchial bar 0=absent, 1=present 114. First pharyngeal bar (mandibular). 0=undifferentiated, 1=differentiated 115. Eyes 0=absent, unpaired or ocelli=1, paired=2 (MH#13mod) 116. Notochord absent = 0, present = 1 (MH#12) DATA SET Hemichordata 0-00-0000-000-0---0---00--0000?0-0?000-000000---0----00000-000-0000-0000000000-0----0--0---0--000-0---0-0----00?0-00 Myllokunmingia 1?????????????????????????101?00?100?1??????100?0000????00-?10-00?????0?000?00-0----0--0---0-0???????????-?--?????21 Pikaia ???????????????????????????01100??00????????0-0?0000????00-?00-00?????00000?00-0----0--0---0--???????????-?--?????11 Metaspriggina 1???????????1?111??????????01?00?100?1??????????0000????00-?10-00?????0?000?00-0----0--0---0-0??????0????-?--2111021

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Haikouichthys 1???????????1?111?1????????01?00?100?1??????10010000?1??00-?10-00?????0?000?0000--0-0--0-0-0-0??????0????-?--21???21 Petromyzontida 10111110101110111111001110101100110111110010110100011011111111110110011000010000--0-0-00-0-00011111101111-0--2201121 Jawed_vertebrates 1111111101111-0-111111111100100101000111111011110112201000-010-011111000111010111110100011001111000012111-1102111121 Jamoytius ????????????1?10???????????0010???10????????????100??01???-?????0????1001???1??0--0-?100-0-000??????0????0??-2????21 Euphanerops ??????????????????????????10010??110?????????11110011?1?????1???0????100?0?10000--?-0?00-0-000???????????01--2????21 Arandaspida ??1????????????????????110100100??00????????010?000??01??0-?????0?????001???1101?2111111011?1??????0?????-?112????21 Osteostraci ?011?11?????1011?10111?111101-11?110?11?01?1110101022011?0-?1??00?1110001110101100101001010111?????101?1?-?112?01021 Euconodonta ?????????????????1?????????????????0????????01010001101?00-????10????00?000?1001?10-1?0010-000???????????-?1-2????1? Tunicata 1-10-0000-000-0---?0--00--010??00000001000000?0000000?0000-000-00-00000000000000--0-0-00-00000001011---------1--0-01 Cephalochordata 0-10-00000000-0---?0--00--000000100110-010000?000000010000-000-00-00000000000000--0-0-00-00000000011---------1000-11 Mesomyzon ??????????????????1???????101?0??101?????????10?000110???11?????0?????10000?0000--0-0-00-0-000???????????-?--2????21 Myxinoidea 100101001101111000110001001(0 1)000010001100101101000000111110-1?1110000000100010000--0-0-00-0000000110-00000-?--2201121 Myxinikela ????????????1?10??1???????101?0???00????????010?0000?0???0-?????0?????01000?0000--0-0-00-0-000??????0????-?--2????21 Priscomyzon ??????????????????0???????101?0???011???????000?000?????1101????0????110000?0000--0-0-00-0-000???????????-?--2????21 Mayomyzon ?????????????0????0???????101?0???011???????010?000(0 1)0??????1?1??0????100000?0000--0-0-00-0-000???????????-?--2????21 Heterostraci ?11???1?????????1?0110?111111000?100???????101000003111??0-?1??00?????00100?110110111001011000?????0?1???-?112????21

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Astraspis ??1??????????????????0?100101100???????????1?1??000???1?????????0???????100?11011210101??11??0?????0?????-?102????21 Anaspida ??1?????????1?11???????110100100??00????????01111001101??0-?????0?????00100?1100--0-1101010000?????10????(0 1)?102????21 Galeaspida ?11??11?????11111?0111?111101-10?110?????1?1?1??000??011?0-?1??00?11100010101100--0-1001010100?????101???-?012?01021 Loganellia ???????????????????????111?01101??00????????11101003101??0-????00?????00100?1101000-1000110000???????????1?002?????1 Turinia ??????????????????????????1011?1??00?????????1?010??1?1?????????0?????0010??1101100-10001100?0???????????1?002?????1 (0,1)=polymorphism REMARKS In both Metaspriggina and Haikouichthys, the two structures preserved between the eyes interpreted as nasal sacs are close together. This suggests the presence of as single median duct (which did not preserve) suggesting a monorhinous condition. In this analysis, characters  13  and  15  were  coded  as  present,  character  16  as  dorsal  and  character  101  as  single. ANALYSES Methods Phylogenetic analyses were performed following the same procedures as in Sansom et al.1 to allow for direct comparisons of results. Data matrices were constructed using Mesquite13 (version 2.0). All analyses were performed using PAUP (version 4.0b10)14 based on unordered characters and we used Hemichordata as the outgroup. All searches were done using the heuristic module with 1000 random sequence addition and rescaled consistency indices. In the parsimony options, multistate taxa were coded as polymorphic. Following Sansom et al.1 heuristic searches were done without constraints and by adding a backbone constraint for cyclostome monophyly to the Nexus file after the matrix as follow: BEGIN paup; constraints Cyclostome = (((Petromyzontida, Priscomyzon, Mayomyzon, Mesomyzon), (Myxinoidea, Myxinikela))); endblock; Bremer supports for each node were also calculated using PAUP. We then used mesquite to reconstruct ancestral character states on the topology of the consensus trees for a specific suite of characters related to the pharyngeal area.

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RESULTS * No backbone constraint: We obtained 8 best trees with the following statistics: Tree length = 84.67 Consistency index (CI) = 0.847 Homoplasy index (HI) = 0.161 Retention index (RI) = 0.897 Rescaled consistency index (RC) = 0.760 1) Strict consensus (with Bremer supports)

2) 50% majority rule (with Bremer supports in bold and node frequencies)

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* Backbone constraint: We obtained 5 best trees with the following statistics: Tree length = 79.35 Consistency index (CI) = 0.823 Homoplasy index (HI) = 0.1803 Retention index (RI) = 0.885 Rescaled consistency index (RC) = 0.733 1) Strict consensus (with Bremer supports)

2) 50% majority rule (with Bremer supports in bold and node frequencies)

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* Backbone constraint: We obtained 5 best trees with the following statistics: Tree length = 79.35 Consistency index (CI) = 0.823 Homoplasy index (HI) = 0.1803 Retention index (RI) = 0.885 Rescaled consistency index (RC) = 0.733 1) Strict consensus (with Bremer supports)

2) 50% majority rule (with Bremer supports in bold and node frequencies)

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Discussion: The overall topologies are similar to previous studies with cyclostomes being paraphyletic in the unconstrained trees. Metaspriggina falls into a polytomy (strict consensus trees) or forms a clade (50% majority rule trees) with Myllokunmingia and Haikouichthys as a basal stem group vertebrate. This clade is at present poorly defined by the presence of otic capsule anterior to branchial series (#19), elongate branchial series with less than 10 pouches/slits (#29), dorsal fin present (#45) and internal pharyngeal bars (#112) (all these characters are homoplastic) and it is not clear whether Metaspriggina possessed a dorsal fin and otic capsules. Reconstructed ancestral states (based on the constrained strict consensus tree) for pharyngeal characters 27(A), 111(B), 112(C), 113(D), 114(E) are presented below. White bars = absence (coded 0), black or green bars = presence (coded 1 or 2), light grey bars = missing or unknown (coded – or ?) and dark grey bars = equivocal change. A

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Discussion: The overall topologies are similar to previous studies with cyclostomes being paraphyletic in the unconstrained trees. Metaspriggina falls into a polytomy (strict consensus trees) or forms a clade (50% majority rule trees) with Myllokunmingia and Haikouichthys as a basal stem group vertebrate. This clade is at present poorly defined by the presence of otic capsule anterior to branchial series (#19), elongate branchial series with less than 10 pouches/slits (#29), dorsal fin present (#45) and internal pharyngeal bars (#112) (all these characters are homoplastic) and it is not clear whether Metaspriggina possessed a dorsal fin and otic capsules. Reconstructed ancestral states (based on the constrained strict consensus tree) for pharyngeal characters 27(A), 111(B), 112(C), 113(D), 114(E) are presented below. White bars = absence (coded 0), black or green bars = presence (coded 1 or 2), light grey bars = missing or unknown (coded – or ?) and dark grey bars = equivocal change. A

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Gill pouches (#27): This character is likely a synapomorphy of vertebrates +Metaspriggina+Myllokunmingia+Haikouichthys and was lost in jawed vertebrates and Loganellia. B

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Gill pouches (#27): This character is likely a synapomorphy of vertebrates +Metaspriggina+Myllokunmingia+Haikouichthys and was lost in jawed vertebrates and Loganellia. B

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Segmented branchial (pharyngeal) bars (#111 - green): This character is also probably synapomorphy of vertebrates+Metaspriggina+Myllokunmingia+Haikouichthys. The evolution of a cyclostome branchial basket (in black) probably represents a latter event. C

Pharyngeal bars internal (#112). This character is homoplastic and is only present in Metaspriggina and jawed vertebrates suggesting it is possibly convergent but this character could also be ancestral and possibly lost in cyclostomes.

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D

Mandibular branchial bar (#113): This character is possibly of synapomorphy of all vertebrates + Metaspriggina+Myllokunmingia+Haikouichthys. E

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Mandibular branchial bar differentiated (#114): A differentiated mandibular bar exist in cyclostomes and jawed vertebrates but this character is homoplastic and possibly convergent. REFERENCES 1   Sansom,  R.  S.,  Freedman,  K.  I.  M.,  Gabbott,  S.  E.,  Aldridge,  R.  J.  &  Purnell,  M.  

A.  Taphonomy  and  affinity  of  an  enigmatic  Silurian  vertebrate,  Jamoytius  kerwoodi  White.  Palaeontology  53,  1393-­‐1409  (2010).  

2   Janvier,  P.  The  dawn  of  the  vertebrates:  characters  versus  common  ascent  in  the  rise  of  current  vertebrate  phylogenies.  Palaeontology  39,  259-­‐287  (1996).  

3   Donoghue,  P.  C.  J.,  Forey,  P.  L.  &  Aldridge,  R.  J.  Conodont  affinity  and  chordate  phylogeny.  Biological  Reviews  75,  191-­‐251  (2000).  

4   Donoghue,  P.  C.  J.  &  Smith,  M.  P.  The  anatomy  of  Turinia  pagei  (Powrie),  and  the  phylogenetic  status  of  the  Thelodonti.  Earth  and  Environmental  Science  Transactions  of  the  Royal  Society  of  Edinburgh  92,  15-­‐37  (2001).  

5   Gess,  R.  W.,  Coates,  M.  I.  &  Rubidge,  B.  S.  A  lamprey  from  the  Devonian  period  of  South  Africa.  Nature  443,  981-­‐984  (2006).  

6   Shu,  D.-­‐G.  et  al.  Lower  Cambrian  vertebrates  from  south  China.  Nature  402,  42-­‐46  (1999).  

7   Shu,  D.-­‐G.  et  al.  Head  and  backbone  of  the  Early  Cambrian  vertebrate  Haikouichthys.  Nature  421,  526-­‐529  (2003).  

8   Conway  Morris,  S.  &  Caron,  J.-­‐B.  Pikaia  gracilens  Walcott,  a  stem-­‐group  chordate  from  the  Middle  Cambrian  of  British  Columbia.  Biological  Reviews  87,  480-­‐512  (2013).  

9   Conway  Morris,  S.  A  redescription  of  a  rare  chordate,  Metaspriggina  walcotti  Simonetta  and  Insom,  from  the  Burgess  Shale  (Middle  Cambrian),  British  Columbia,  Canada.  Journal  of  Paleontology  82,  424-­‐430  (2008).  

10   Mallatt,  J.  &  Holland,  N.  Pikaia  gracilens  Walcott:  stem  chordate,  or  already  specialized  in  the  Cambrian?  Journal  of  experimental  zoology.  Part  B,  Molecular  and  developmental  evolution  320,  247-­‐271  (2013).  

11   Mallatt,  J.  Early  vertebrate  evolution:  pharyngeal  structure  and  the  origin  of  gnathostomes.  Journal  of  Zoology  204,  169-­‐183  (1984).  

12   Mallatt,  J.  Ventilation  and  the  origin  of  jawed  vertebrates:  a  new  mouth.  Zoological  Journal  of  the  Linnean  Society  117,  329-­‐404  (1996).  

13   Mesquite:  a  modular  system  for  evolutionary  analysis  v.  2.0  (2007).  14   PAUP:  Phylogenetic  Analysis  Using  Parsimony  (*and  Other  Methods)  v.  

4.0b10  (Sinauer  Associates,  Sunderland,  Massachusetts,  2003).    

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Mandibular branchial bar differentiated (#114): A differentiated mandibular bar exist in cyclostomes and jawed vertebrates but this character is homoplastic and possibly convergent. REFERENCES 1   Sansom,  R.  S.,  Freedman,  K.  I.  M.,  Gabbott,  S.  E.,  Aldridge,  R.  J.  &  Purnell,  M.  

A.  Taphonomy  and  affinity  of  an  enigmatic  Silurian  vertebrate,  Jamoytius  kerwoodi  White.  Palaeontology  53,  1393-­‐1409  (2010).  

2   Janvier,  P.  The  dawn  of  the  vertebrates:  characters  versus  common  ascent  in  the  rise  of  current  vertebrate  phylogenies.  Palaeontology  39,  259-­‐287  (1996).  

3   Donoghue,  P.  C.  J.,  Forey,  P.  L.  &  Aldridge,  R.  J.  Conodont  affinity  and  chordate  phylogeny.  Biological  Reviews  75,  191-­‐251  (2000).  

4   Donoghue,  P.  C.  J.  &  Smith,  M.  P.  The  anatomy  of  Turinia  pagei  (Powrie),  and  the  phylogenetic  status  of  the  Thelodonti.  Earth  and  Environmental  Science  Transactions  of  the  Royal  Society  of  Edinburgh  92,  15-­‐37  (2001).  

5   Gess,  R.  W.,  Coates,  M.  I.  &  Rubidge,  B.  S.  A  lamprey  from  the  Devonian  period  of  South  Africa.  Nature  443,  981-­‐984  (2006).  

6   Shu,  D.-­‐G.  et  al.  Lower  Cambrian  vertebrates  from  south  China.  Nature  402,  42-­‐46  (1999).  

7   Shu,  D.-­‐G.  et  al.  Head  and  backbone  of  the  Early  Cambrian  vertebrate  Haikouichthys.  Nature  421,  526-­‐529  (2003).  

8   Conway  Morris,  S.  &  Caron,  J.-­‐B.  Pikaia  gracilens  Walcott,  a  stem-­‐group  chordate  from  the  Middle  Cambrian  of  British  Columbia.  Biological  Reviews  87,  480-­‐512  (2013).  

9   Conway  Morris,  S.  A  redescription  of  a  rare  chordate,  Metaspriggina  walcotti  Simonetta  and  Insom,  from  the  Burgess  Shale  (Middle  Cambrian),  British  Columbia,  Canada.  Journal  of  Paleontology  82,  424-­‐430  (2008).  

10   Mallatt,  J.  &  Holland,  N.  Pikaia  gracilens  Walcott:  stem  chordate,  or  already  specialized  in  the  Cambrian?  Journal  of  experimental  zoology.  Part  B,  Molecular  and  developmental  evolution  320,  247-­‐271  (2013).  

11   Mallatt,  J.  Early  vertebrate  evolution:  pharyngeal  structure  and  the  origin  of  gnathostomes.  Journal  of  Zoology  204,  169-­‐183  (1984).  

12   Mallatt,  J.  Ventilation  and  the  origin  of  jawed  vertebrates:  a  new  mouth.  Zoological  Journal  of  the  Linnean  Society  117,  329-­‐404  (1996).  

13   Mesquite:  a  modular  system  for  evolutionary  analysis  v.  2.0  (2007).  14   PAUP:  Phylogenetic  Analysis  Using  Parsimony  (*and  Other  Methods)  v.  

4.0b10  (Sinauer  Associates,  Sunderland,  Massachusetts,  2003).    

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2) Metaspriggina walcotti (Simonetta and Insom, 1993). Specimen

occurrences

References Caron, J.-B., Gaines, R. R., Aria, C., Mángano, M. G. & Streng, M. A new phyllopod bed-like assemblage from the Burgess Shale of the Canadian Rockies. Nat Commun 5, (2014). Johnston, K. J., Johnston, P. A. & Powell, W. G. A new Middle Cambrian Burgess Shale-type biota, Bolaspidella Zone, Chancellor Basin, southeastern British Columbia. Palaeogeography, Palaeoclimatology, Palaeoecology 277, 106-126 (2009).

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RESEARCH References Caron, J.-B., Gaines, R. R., Aria, C., Mángano, M. G. & Streng, M. A new phyllopod bed-like assemblage from the Burgess Shale of the Canadian Rockies. Nat Commun 5, (2014). Johnston, K. J., Johnston, P. A. & Powell, W. G. A new Middle Cambrian Burgess Shale-type biota, Bolaspidella Zone, Chancellor Basin, southeastern British Columbia. Palaeogeography, Palaeoclimatology, Palaeoecology 277, 106-126 (2009).

Caron, J.-B. Taphonomy and community analysis of the Middle Cambrian Greater Phyllopod Bed, Burgess Shale Unpublished PhD thesis, University of Toronto, (2005). Simonetta, A. M. & Insom, E. New animals from the Burgess Shale (Middle Cambrian) and their possible significance for the understanding of the Bilateria. Boll. Zool. 60, 97-107 (1993). Conway Morris, S. Ediacaran-like fossils in Cambrian Burgess Shale-type faunas of North America. Palaeontology 36, 593-635 (1993).