Supplementary Information for an Exceptional Devonian Fish from Australia Sheds Light On

Supplementary Information for ‘An exceptional Devonian fish from Australia sheds light on tetrapod origins’

John A. Long1,2, 3, Gavin C. Young2, Tim Holland 1, 3, Tim J. Senden 4 and Erich M. G. Fitzgerald 1,3

1, Museum Victoria, Melbourne, PO Box 666, Melbourne, Australia, 3001; 2, Dept. of Earth and Marine Sciences, The Australian National University, Canberra, Australia, 0200; 3, School of Geosciences, Monash University, Clayton, Victoria, Australia, 3800; 4, Dept. of Applied Mathematics, Research School of Physical Sciences and Engineering, The Australian National University, Canberra, Australia, 0200.

1. Methods and materials

A. Preparation

The specimen was a complete fish preserved in two limestone blocks, the larger containing almost the entire head and body skeleton to the level of the pelvic girdle (showing pelvic basal scutes), and the smaller block (which fitted on to the posterior end of the main block) with an impression of the caudal fin region. Preparation of the main block was by immersion in 10% acetic acid, for 2 day intervals, followed by washing in water, air-drying and then impregnation of the exposed bone surfaces using Mowital B30 (Clariant Chemicals ) diluted with pure ethanol. Photographs of the specimen were taken at each stage of preparation to document the exact position of bones as they came out of the matrix. The tail was prepared by first embedding the exposed surface in epoxy resin to retain articulation of the squamation and posterior fin elements, and the resin block was then acid-etched using the above method. Specimen preparation was carried out by JAL over the period August 2005-February 2006.

B. Tomogram of Otico-occipital unit

High resolution X-ray tomography was conducted in-house (for details see Sakellariou et al. 2004a, b) to explore the relationship between external and internal structures at a spatial resolution of 13 microns. The included animation shows the right posterolateral corner (quadrant) of the otico-occipital. The dermal bone is depicted in translucent brown, and endocranial bones rendered translucent beige. As the specimen rotates the down-turned lamina showing the spiracular border can be clearly seen. Following this rotation the dorsal surface is presented and the specimen is progressively eroded towards the ventral surface. During the erosion we see expression of the semicircular canals of the inner ear, finishing at the floor of the fossa bridgei. All volume rendering and animation was done using the freeware package, Drishti (http://sf.anu.edu.au/~acl900/Drishti/ ).

2. Determining the shape of the spiracular chamber

Supplementary Figure S1 shows the mesial view of the entopterygoid of the new Gogonasus specimen, with the ridge defining the ventral margin of the spiracular chamber clearly indicated. The shape of the spiracular chamber in Gogonasus as in Figure 1h is clearly delineated by this ridge, following the same method as used by Brazeau & Ahlberg (2006, ref. 9) to determine the spiracular chamber shape for Eusthenopteron.

The hyomandibula, and its relationship and orientation with respect to the braincase, were clearly figured by Long et al. (1997, ref. 2) in their Fig. 42G and Fig. 44. The restoration shown in Fig. 60A of that monograph needs slight modification as the opercular process of the hyomandibula sits more posteriorly, taking into account cartilage pads on the synovial surfaces of the hyomandibular facets. This brings into alignment the hyomandibular opercular process and opercular pit on the mesial face of the opercular bone. Nonetheless the actual orientation of the hyomandibula with respect to the skull table is accurate, as verified by the new specimen, bearing in mind the slight degree of vertical movement afforded by the cartilage articulatory surfaces on the hyomandibular head.

3. Phylogenetic methods

Analysis protocol and results:

The character state scores for all taxa, except Gogonasus, Onychodus, Marsdenichthys, and Medoevia, were adapted with modifications from Ahlberg & Johanson (1998), Daeschler et al. (2006) and Shubin et al. (2006). Marsdenichthys was scored, with modifications, from information in Long (1985). Medoevia was scored, with modifications (JAL has studied the original specimen) primarily from information in Lebedev (1995), and for Eusthenopteron and Megalichthys characters were taken from Andrews & Westoll (1970a, b), and Jarvik (1966) as well as personal observation of material by one of us (JAL). Character data entry and formatting was performed in MacClade (version 4.05) (Maddison & Maddison 2002). The matrix includes 103 morphological characters in 12 taxa, of which 9 were based on fairly complete specimens with few missing codings. All characters were treated as unordered, and all characters were weighted equally. The data matrix was analysed with parsimony using PAUP* (version 4.0b10) (Swofford 2002). The analysis protocol consisted of a branch and bound analysis, with furthest addition sequence, and multiple trees saved. Branches were collapsed if the minimum branch length was zero (“amb-” option) (see Kearney & Clark 2003 for discussion). Where taxa were coded for multiple states, the coding was interpreted as uncertainty. Where taxa were coded for gaps, the gap coding was interpreted as an additional state. Character state optimisation was ACCTRAN. Onychodus was employed as an outgroup, and outgroup rooting was used.

The analysis of the data set found 2 shortest trees of 190 steps [consistency index (CI) = 0.7526; retention index (RI) = 0.7902; rescaled consistency index (RC) = 0.5947]. In both of the most parsimonious trees Gogonasus is posited crownward of all other tetrapodomorphs usually referred to as ‘osteolepiforms’, and is the sister group of the elpistostegalians. Thus, this analysis shows that Gogonasus is clearly not nested within the taxa formerly referred to as ‘osteolepidids’, contra the hypothesis of Ahlberg & Johanson (1998).

The clade consisting of Gogonasus + Elpistostegalia is diagnosed by the following synapomorphies: wide spiracular notch (ch. 54: 1 Þ 2); short ventral process on the entepicondyle is present (ch. 61: 0 Þ 1); supracleithrum and postemporal are small, scale-like bones (ch. 69: 0 Þ 1); body of humerus is flattened and rectangular (ch. 79: 0 Þ 1); and the entepicondyle is narrow (ch. 82: 1 Þ 0). Notably, Eusthenopteron occupies a basal position in the phylogeny presented here, being more basal than Medoevia, Megalichthys, and Gogonasus. This is in stark contrast to previous studies, which have posited Eusthenopteron (with other taxa) in the clade Tristichopteridae as the sister group to Elpistostegalia (Panderichthys, Tiktaalik + Tetrapoda) (e.g. Ahlberg & Johanson 1998; Daeschler et al. 2006).

These results demonstrate, once again, that the ‘Osteolepididae’ and more broadly the ‘Osteolepiformes’ are both paraphyletic groupings of tetrapodomorphs as suggested by Ahlberg & Johanson (1998). Given the importance of the ‘Osteolepiformes’ to understanding character evolution in the fish-tetrapod transition (and palaeobiological issues therein), it is critical that the question, “What, if anything, is an osteolepiform?” be addressed through a thorough cladistic analysis of all relevant tetrapodomorph taxa. Only then will it be possible to offer a cladistic redefinition of ‘osteolepiform’ taxa. Such a study is beyond the scope of this essay, but we acknowledge the problem here to highlight the need for resolution of this issue.

References Ahlberg, P. E. & Johanson, Z. Osteolepiformes and the ancestry of tetrapods. Nature 395, 792-794 (1998). Andrews, S.M. & Westoll, T.S. The postcranial skeleton of Eusthenoptero foordi Whiteaves. Trans. R.Soc. Edinb. 68: 207-329 (1970a). Andrews, S.M. & Westoll, T.S. The postcranial skeleton of rhipidistian fishes excluding Eusthenopteron. Trans. R.Soc. Edinb. 68: 391-489 (1970b). Daeschler, E. B., Shubin, N. H. & Jenkins Jr., F. A. A Devonian tetrapod- like fish and the evolution of the tetrapod body plan. Nature 440, 757-763 (2006). Jarvik, E. Remarks on the structure of the snout in Megalichthys and certain other rhipidistid crossopterygians. Ark. Zool. 18: 305-389 (1966). Kearney, M. & Clark, J. M. Problems due to missing data in phylogenetic analyses including fossils: a critical review. J. Vertebr. Paleontol. 23, 263-274 (2003). Lebedev, O. A. Morphology of a new osteolepidid fish from Russia. Bull. Mus. natl. Hist. nat., Paris, 4e sér., Section C 17, 287-341 (1995). Long, J. A. The structure and relationships of a new osteolepiform fish from the Late Devonian of Victoria, Australia. Alcheringa 9, 1-22 (1985). Maddison, D. R. & Maddison, W. P. MacClade. Version 4. Sunderland: Sinauer Associates, Inc (2002). Sakellariou, A., Sawkins, T.J., Limaye, A. & Senden, T.J. 2. X-ray Tomography for Mesoscale Physics Applications. Physica A 339, 152- 158 (2004a) Sakellariou, A., Senden, T.J., Sawkins, T.J., Knackstedt, M.A., Turner, M.L., Jones, A.C., Saadatfar, M., Roberts, R.J., Limaye, A., Arns, C.H., Sheppard, A.P. & Sok, R.M. 2004b. An x-ray tomography facility for quantitative predictions of mechanical and transport properties in geological, biological and synthetic systems, in Development in X-Ray Tomography IV (edited by Ulrich Bonse), Proceedings of SPIE Vol. 5535, 473-484 (SPIE, Bellingham, WA, 2004b). Shubin, N. H., Daeschler, E. B. & Jenkins Jr., F. A. The pectoral fin of Tiktaalik rosae and the origin of the tetrapod limb. Nature 440, 764- 771 (2006). Swofford, D. L. PAUP*. Phylogenetic Analysis Using Parsimony (*and Other Methods). Version 4. Sunderland: Sinauer Associates, Inc. (2002).

Characters

Characters used in previous analyses:

D = taken from Daeschler et al 2006, which are all characters listed below except for new characters (N) which are: 2,4,33,43, 48 67,69,82, 92, 94, 102 and 103. We include a short rationale of how all new characters were polarised.

1. Cosmine:: (D26) 0. present 1. absent

2. Lacrimal bone and posterior naris: (N) 0. lacrimal always participates in posterior border to posterior naris 1. lacrimal does not usually participate in narial opening As Psarolepis, Youngolepis, and basal actinopterygians (Mimia) have the posterior naris bounded by the anterior of the lacrimal bone, we code this as the plesiomorphic state. Coding for Gogonasus is 0/1 as in one specimen the lacrimal does participate in the narial border (MV P221807).

3. Dermal intracranial joint:: (D50) 0. present 1. absent

4. Hyomandibula orientation: (N) 0. posteroventral, distally terminating near jaw joint 1. almost horizontal orientation, opercular process high up dorsally 2. very short, laterally directed

The plesiomorphic state is seen in the long, posteroventrally directed hyomandulae of basal actinopterygians, and in Onychodus.

5. Parasymphysial plate: : (D1) 0. long, not sutured to coronoid, denticulate or with tooth row 1. short, sutured to coronoid, denticulated 2. compressed, unsutured, carrying tooth whorl

6. Mesial parasymphysial foramen:: (D67) 0. absent 1. present

7. Anterior end of prearticular:: (D2) 0. not forked 1. forked

8. Prearticular and angular:: (D3) 0. separated by ventral exposure of Meckelian bone 1. in contact

9. Mesial lamina of splenial:: (D62) 0. absent 1. present

10. Prearticular:: (D4) 0. rear part with conspicuous horizontal ledge 1. rear part flat

11. Number of coronoids:: (D5) 0. more than three 1. three

12. Meckelian exposure in precoronoid fossa:: (D65) 0. present 1. absent 13. Coronoid proportions:: (D6) 0. posterior coronoid same length as middle coronoid, or shorter 1. posterior coronoid significantly longer than middle coronoid

14. Accessory tooth row on dentary:: (D64) 0. present 1. absent

15. Dentary fang pair:: (D8) 0. absent 1. present

16. Number of fang pairs on posterior coronoid:: (D9) 0. one 1. two 2. none

17. Suture between anterior coronoid and splenial:: (D63) 0. absent 1. present

18. Coronoid fangs mesial to marginal tooth row:: (D71) 0. yes 1. no

19. Palatal fangs mesial to marginal tooth row:: (D72) 0. yes 1. no

20. Coronoid fangs larger than marginal teeth:: (D70) 0. yes 1. no

21. Tooth infolding:: (D10) 0. none 1. generalized polyplocodont 2. labyrinthodont 3. dendrodont

22. Number of fang pairs on ectopterygoid:: (D12) 0. one 1. two 2. none

23. Proportions of entopterygoid:: (D13) 0. anterior end level with processus ascendens 1. anterior end anterior to processus ascendens

24. Entopterygoids meeting in midline:: (D14) 0. no 1. yes

25. Posterior process of vomer:: (D15) 0. absent 1. short 2. long

26. Vomers, anteromedial process:: (D16) 0. absent, vomers widely separated 1. present 2. absent, vomers in close contact

27. Relationship of vomer to parasphenoid:: (D18) 0. no contact, or simple abutment 1. overlap or sutured with vomer

28. Internasal pits:: (D19) 0. undifferentiated 1. deep pear - shaped pits

In Daeschler et al. (2006) they use 3 states but as our taxa do not exhibit any differentiation between absent or very small spiracular slit, we have combined these as the basal state (0). State 1 only refers to the 2 outgroup taxa here.

29. Posterior end of parasphenoid:: (D20) 0. denticulate field extends into spiracular groove 1. denticulate field does not extend into spiracular groove

30. Choana:: (D22) 0. absent 1. present

31. Width of ethmoid relative to length from snout tip to posterior margin of parietals:: (D24) 0. more than 80% 1. 70% - 80% 2. 50% - 70% 3. less than 40%

32. Endoskeletal intracranial joint:: (D51) 0. absent 1. present

33. Basipterygoid process: (N) 0. small knob-like process 1. developed as a broad platform

The plesiomorphic state is seen in basal actinopterygians and Onychodus.

34. Basicranial fenestra:: (D52) 0. absent 1. present

35. Extent of crista parotica:: (D28) 0. does not reach posterior margin of tabular 1. reaches posterior margin of tabular

36. Pineal foramen:: (D27) 0. present 1. absent

37. Proportions of postparietal shield:: (D31) 0. wide posteriorly 1. narrow posteriorly 2. fused as part of skull table

We have coded the wide postparietal shield as plesiomorphic based on porolepiforms, and Psarolepis, and add one extra state (2) here to reflect the derived condition in tetrapods. State 0, ‘wide’ equates to being more than twice as broad posteriorly than anteriorly (e.g. Glyptolepis). State 1, narrow posteriorly is where the anterior margins of the shield are more then 50% of the posterior margin.

38. Postparietals narrow to a point posteriorly:: (D32) 0. no 1. yes

39. Posterior margin of tabulars:: (D33) 0. anterior to posterior margin of postparietals 1. level with posterior margin of postparietals

40. Median postrostral:: (D34) 0. absent (postrostral mosaic) 1. present 2. absent (nasals meet in midline)

41. Number of nasals:: (D35) 0. many 1. one or two

42. Frontals:: (D36) 0. absent 1. present

43. Shape of spiracular chamber: (N) 0. Very large, steeply inclined anteriorly 1. Acutely inclined anteriorly 2. Horizontal The difference between state 0 (Eusthenopteron, Onychodus) and condition seen in both Gogonasus and Medoevia (1) is whether the angle of the inner entopterygoid ridge denoting the lateral boundary of the spiracular chamber is steeply inclined (>45deg.) or closer to the horizontal (acute angle).

44. Extratemporal:: (D37) 0. present 1. absent

45. Contact between the extratemporal and supratemporal:: (D38) 0. absent 1. present

46. Posterodorsal process of maxilla:: (D41) 0. present, deep throughout its length 1. wedge shaped, deep posteriorly 2. weak or absent

In Daeschler et al. (2006) they use 2 character states here but we have expanded this to three states and made the plesiomorphic condition to include onychodontids which have a uniformly broad posterodorsal process on the maxilla, as in basal actinopterygians.

47. Jugal - quadratojugal contact:: (D42) 0. absent 1. present

48. Radius and ulna facets: (N) 0. in same transverse plane 1. stepped, in different planes

The stepped articulatory facets on Eusthenopteron are assumed present in Megalichthys as Andrews & Westoll (1970a) claim the humerus is essentially similar to that of Eusthenopteron. As the condition seen in Onychodus and in the larval lungfish Neoceratodus is to have ulna and radial facets at the same levels, we regard the stepped condition as derived.

49. Position of orbits:: (D45) 0. lateral and widely spaced 1. dorsal and close together

50. Extrascapular overlap:: (D48) 0. no strong overlap 1. lateral overlap median 2. median overlaps lateral

51. Anterior margin of median extrascapular:: (D49) 0. broad, extensive contact 1. point or very short contact We regard the primitive state as seen in basal osteichthyans as having a broad median extrascapular contact with postparietal shield (onychodonts, porolepiforms, dipnoans bone A).

52. Dermal ornament: (D69) 0. even 1. separate "starburst" on each bone

53. Intertemporal bones:: (D75) 0. present 1. absent

54. Spiracular notch:: (D87) 0. absent-very small 1. narrow groove 2. wide notch

‘Wide’ notch here refs to the expanded size of the opening as in Gogonasus, Panderichthys and Tiktaalik.

55. Proportion of skull roof (measured as length from tip of snout to posterior margin of postparietals) lying anterior to middle of orbits:: (D75) 0. 0 - <50% 1. 1 - 50% 2. >50%

56. Relative size of prefrontal and postfrontal:: (D76) 0. similar 1. prefrontal much bigger

57. Postfrontals extend anterior of orbits:: (D86) 0. yes 1. no

58. Extrascapular bones:: (D77) 0. present 1. absent

59. Jugal extends anterior to middle of orbit:: (D78) 0. no 1. yes

60. Lacrimal excluded from orbit:: (D79) 0. no 1. yes

61. Short ventral process on entepicondyle: (N) 0. absent 1. present As this process is absent on most tetrapodomorphan humeri, we consider it a derived feature. This process is here shown clearly on Fig 2a for Gogonasus and seen on Tiktaalik in Shubin et al., 2006, Fig 2a.

62. Opercular:: (D111) 0. present 1. absent

63. Submandibulars and Gulars:: (D80) 0. present 1. absent

64. Preopercular:: (D88) 0. large, broad 1. large, bar-like 2. small

65. Large median gular:: (D81) 0. absent 1. present

66. Sublingual rod: (N) 0. absent 1. present

The plesiomorphic state is taken to be the absence of a sublingual rod as it is not found in any actinopterygians, or in porolepiforms.

67. Clavicle ascending process: (N) 0 Clavicle has rod-like ascending process 1. Clavicle lacks rod-like ascending process

The ascending process here defined as an extended narrow process, not just a process or corner of the posterolateral corner of the clavicle. In basal osteichthyans like Mimia and Onychodus there is well-developed ascending process, but in forms like Gogonasus the anterolateral corner of the clavicle ends with an acute point, but is not drawn out into a rod-like process.

68. Interclavicle:: (D83) 0. small, unornamented 1. large, ornamented

69. Supracleithrum and postemporal: (N) 0. enlarged, bigger than scales 1. small, scale-like bones 2. lost from shoulder girdle

We here code the plesiomorphic state as seen in basal actinopterygians (e.g. Mimia) in which these bones are relatively larger than regular scales, and may have different shapes from that of the scales. The condition of having small scale like bones in these positions is identified for Tiktaalik and is also seen in Gogonasus.

70. Anocleithrum:: (D54) 0. exposed 1. subdermal

71. Orientation of cleithrum:: (D105) 0. vertically oriented: tilted less than 10 degrees caudally 1. angulated: tilted over 10 degrees caudally

72. Cleithrum ornamentation: (D106) 0. present 1. absent

73. Contact margin for clavicle on cleithrum:: (D53) 0. straight or faintly convex 1. strongly concave

74. Attachment of scapulocorocoid to cleithrum:: (D108) 0. tripodal, via three processes 1. via a single dorsal process of scapulocorocoid that lies flush against internal surface of cleithrum 2. complete fusion between surfaces of the scapula and cleithrum

75. Glenoid position:: (D104) 0. elevated from plane formed by clavicles 1. offset ventrally to lie at same level as clavicular plane

76. Glenoid orientation:: (D110) 0. posterior and/or ventral orientation 1. lateral component to glenoid orientation

77. Coracoid plate:: (D103) 0. absent 1. present and extends ventromedially

78. Subscapular fossa: : (D109) 0. absent 1. present

79. Body of humerus:: (D56) 0. cylindrical 1. flattened rectangular

80. Caput humeri:: (D112) 0. rounded to hemispherical shaped 1. subrectangular, much wider than high 2. elongate (bifid or strap - shaped) In Daeschler et al. (2006) only 2 states are defined (0, ball-like or1, strap- like). After closer examination of the humeri of a number of tetrapodomorphs, we have added an extra state to accommodate the condition seen in Gogonasus where it is neither ball-shaped nor strap-like, but extensively wide and of uniform width.

81. Radial facet:: (D98) 0. faces distally 1. has some ventrally directed component

82. Entepicondyle size: (N) 0. entepicondyle narrow relative to humerus shaft length 1. entepicondyle as broad as or broader than humerus is long

Based on plesiomorphic archipterygial fin patterns (e.g. dipnoans, porolepiforms) we assume that primary mesomere (A1) lacks a well- developed entepicondyle, so the extensive developments of such a feature are here considered to be derived within tetrapodomorphs. We measure the entepicondylar process as being the ventrally-orientated flange coming off the humeral shaft, measured from the ventral humeral shaft edge to its widest extent relative to maximum humeral shaft length. Thus in Gogonasus, as shown in Fig.1a, the entepicondyle is clearly much shorter in its width than the humerus is long.

83. Anterior termination of ventral ridge:: (D96) 0. adjacent to the caput humeri 1. offset distally toward the proximodistal mid - region of anterior margin of humerus

84. Ectepicondylar process:: (D100) 0. terminates proximal to epipodial facets 1. extends distal to epipodial facets

85. Area proximal to radial facet:: (D102) 0. short, cylindrical leading edge, with no muscle scars 1. enlarged, sharp leading edge, with areas for muscle attachment

86. Articulations for more than two radials on the ulnare:: (D90) 0. several radials articulate with ulnare 1. articulates mainly with one large A4 element and/or other much smaller radials

87. Postaxial process on ulnare:: (D91) 0. present 1. absent

88. Ventral ridge orientation:: (D97) 0. diagonal to long axis of the humerus 1. perpendicular to long axis of humerus 89. Radials:: (D57) 0. jointed 1. unjointed

90. Radius shape: (D94) 0. narrow, tapered or even breadth throughout 1. broad (almost as wide as long) or flared distally

We clarify our definition of this character as expressed by Daeschler et al. (2006) by stating that the plesiomorphic radius must have been rod-like, not broad or expanded, as it is in the small radials in dipnoans and porolepiform pectoral fins.

91. Radial length:: (D101) 0. longer than humerus 1. shorter than humerus

92. Termination of radius: (N) 0. radius and intermedium terminate at different levels 1. radius and intermedium terminate at same level

93. Transverse joint at the level of the ulnare, intermedium and radius:: (D89) 0. absent 1. present

94. Intermedium shape: (N) 0. narrow, tapered 1. broad or flared

Using the same rationale as for Ch.91, the plesiomorphic state must be having a simple, rod –like intermedium.

95. Dorsal and anal fins:: (D58) 0. present 1. absent

96. Caudal fin:: (D59) 0. heterocercal 1. diphycercal

97. Scale morphology:: (D61) 0. rhomboid with internal ridge 1. round without median boss 2. rounded, with median boss 3. elongated, oval- round We have added extra states here to differentiate between rounded scales with a median boss (derived and restricted distribution) and tetrapod scales that are elongated and oval-shaped.

98. Basal scutes:: (D60) 0. absent 1. present

99. Lepidotrichia:: (D92) 0. present and jointed in region that overlaps endochondral elements 1. present and unjointed in region that overlaps endochondral elements 2. absent

100. Imbricate ribs:: (D113) 0. absent 1. present

101. Expanded ribs:: (D114) 0. absent 1. present

102. Shape of mesomere A4: (N) 0. narrow or tapered 1. short, relatively broad

This feature is only known for a few tetrapodomorphans so polarity is difficult to establish. We have based it on the observation that Tiktaalik probably has a derived condition, so the plesiomorphic condition is might be seen in Eusthenopteron.

103. Shape of mesomere A5: (N) 0. narrow and or tapered 1. broadens posteriorly

This character is polarised as for Ch. 105. Character Matrix

1 11111 11112 22222 22223 33333 33334 44444 12345 67890 12345 67890 12345 67890 12345 67890 12345

Onychodus 10002 00000 00000 20000 01000 001?0 010?? 11001 10001 Glyptolepis 10000 00000 10000 00000 30000 00100 0111? 10000 00000 Barameda 110?1 000?0 10?01 10000 11000 0?0?1 011?? 01101 10?01 Marsdenichthys 110?1 ????? ???00 ???00 ???0? 100?1 11??? 01011 10?00 Eusthenopteron 1100? 00000 10100 10000 11102 11011 31111 01011 0001- Medoevia 01011 00000 10000 00000 10100 11011 11111 0101? ?0100 Megalichthys 010?1 00000 10000 00000 10?00 11011 11111 11011 10?00 Gogonasus 00/1011 00000 10000 00000 10100 11011 11111 01101 10100 Panderichthys 11121 00101 10101 20000 20?02 11011 31110 01012 0121- Tiktaalik 11121 00?0? 10101 200?0 20102 110?1 3???? 01012 ?121- Acanthostega 10121 11111 01111 21111 22111 10011 2010? 02012 1121- Ichthyostega 10121 11111 01111 21111 22111 10011 2010? 02012 11?1-

44445 55555 55556 66666 66667 77777 77778 88888 88889 67890 12345 67890 12345 67890 12345 67890 12345 67890

Onychodus 00000 00000 --000 00000 ?0?01 00100 00011 00?0? ??-0? Glyptolepis 20-02 00?00 ?0000 00000 00000 00000 00000 ?-??? -??0- Barameda 2?000 00000 00000 00000 ?00?1 00000 00000 01000 0101? Marsdenichthys 10?01 00010 00000 ?0010 ?1?00 000?? ????? ????? ???0? Eusthenopteron 10101 00010 00000 00010 10000 00100 00000 01000 00001 Medoevia 10?01 0/10010 00000 00010 1?000 00000 00001 01000 ??00? Megalichthys 10101 00010 00000 00010 ?1?00 00000 00000 01000 00000 Gogonasus 10001 10020 00000 10010 11010 00000 00011 1000/10 10000 Panderichthys 2?011 00020 00000 ?0011 11010 10111 11112 00001 ??000 Tiktaalik 2101- -0122 11110/1 11021 11?10 10111 11112 10101 11010 Acanthostega 21?1- -1122 11111 11120 0012? 11?21 11112 00111 ----0 Ichthyostega 21?1- -1121 11111 ?112- ?012? 01?20 11112 10111 ----1

111 99999 99990 000 12345 67890 123

Onychodus ????0 11000 0?? Glyptolepis ?-0-0 01000 0?? Barameda 0001? ?1010 000 Marsdenichthys ????0 ?210? ??? Eusthenopteron 00010 12100 000 Medoevia ????0 ?010? ??? Megalichthys 0??00 00100 ?0? Gogonasus 01000 00100 011 Panderichthys 11001 10010 1?? Tiktaalik 11101 ?001? 111 Acanthostega 1-- 11 13020 0-- Ichthyostega 11- -1 1?021 1-- Supplementary Information Figure S1: