Appendix 1 - Taxa and Specimen Resource List

The following is a list of taxa analyzed and compared in this study, with references to descriptive papers used in the analysis of each.

Outgroup:

Lesothosaurus diagnosticus Galton, 1978–Thulborn (1970, 1972), Santa Luca (1984), Weishampel and Witmer (1990a), Sereno (1991a), Norman, (2004)

Basal Ornithopod Taxa:

Hypsilophodon foxii Huxley, 1869–Galton (1974a), Norman (2004)

Parksosaurus warreni Parks, 1926–Parks (1926), Sternberg (1940), Galton (1973)

Thescelosaurus neglectus Gilmore, 1913–Gilmore (1913), Gilmore (1915), Sternberg (1940), Galton (1974b, 1995, 1997), Norman et al. (2004)

Basal Iguanodontian Taxa:

Camptosaurus dispar (Marsh, 1879)–Marsh (1879), Gilmore (1909), Norman (2004)

Cumnoria prestwichii Hulke 1880–Hulke (1880), Galton and Powell (1980), Norman (2004)

Dryosaurus altus (Marsh, 1878)–Marsh (1878), Galton (1983), Norman (2004)

Eolambia caroljonesa Kirkland, 1998–Kirkland (1998), Head (2001), Norman (2004), McDonald et al. (2012)

Iguanodon bernissartensis Boulenger, 1881–Boulenger (1881), Norman (1980), Norman (2004)

Jinzhousaurus yangi Wang and Xu, 2001–Wang and Xu (2001), Barrett et al., (2009), Wang et al. (2011)

Mantellisaurus atherfieldensis (Hooley, 1925)–Hooley (1925), Norman (1986), Norman (2004)

Ouranosaurus nigeriensis Taquet, 1976–Taquet (1976), Norman (2004)

Tenontosaurus dossi Winkler et al., 1997–Winkler et al. (1997), Norman (2004)

Tenontosaurus tilletti Ostrom, 1970–Ostrom (1970), Forster (1990), OMNH 58340 (subadult, primary specimen), OMNH 2531 (juvenile), OMNH 16562 (subadult, skull transversely compressed, palpebral), OMNH 34191 (premaxilla)

Zalmoxes robustus (Nopcsa, 1900)–Nopcsa (1900), Weishampel et al. (2003), Norman (2004)

Hadrosauroid Taxa:

Corythosaurus casuarius Brown, 1914–Brown (1914, 1916), Ostrom (1961), Horner et al. (2004)

Edmontosaurus regalis Lambe 1917–Lambe (1917), Lull and Wright (1942), Norman (2004), Horner et al. (2004)

Probactrosaurus gobiensis Rozhdestvensky, 1966–Rozhdestvensky (1966), Norman (2002), Norman (2004)

Protohadros byrdi Head, 1998–Head (1998), Norman (2004)

Telmatosaurus transsylvanicus (Nopcsa, 1900)–Nopcsa (1900), Nopcsa (1903), Weishampel et al. (1993), Horner et al. (2004)

Appendix 2 - Character Description

The following is a list of character states used in this analysis. States were determined independently, but similarities with previously published analyses (Norman, 2004; McDonald et al., 2010) have been noted.

Facial Characters:

1. Presence of nasal contact with the maxilla and reason for exclusion of contact (Modified from Norman, 2004: Character 6):

1:0. Contact

1:1. No contact due to an anterior extension of the lachrymal

1:2. No contact due to a posterior extension of the premaxilla

2. Character of the occlusal margin of the premaxilla (Modified from McDonald et al., 2010: Character 33):

2:0. Smooth

2:1. Denticulate

2:2. Scooped, possibly to accommodate the denticles of the predentary

3. Premaxillary teeth (Modified from Norman, 2004: Character 3; McDonald et al., 2010: Character 29):

3:0. Present

3:1. Absent

4. Posterior extent of the nasal process of the premaxilla:

4:0. Does not reach antorbital fenestra

4:1. Reaches antorbital fenestra or, if no fenestra present, posterior border of dorsal process of maxilla

5. Beak position relative to tooth row (Modified from Norman, 2004: Character 2):

5:0. At level

5:1. Below

6. Width of combined frontals compared to length (Modified from Norman, 2004: Character 15):

6:0. About 2/3 length of frontal

6:1. About equal to length of frontal

6:2. Twice length of frontal

7. Transverse length of frontals' suture with parietal:

7:0. About equal with combined width of frontals

7:1. About two-thirds combined width of frontals

7:2. About half combined width of frontals

7:3. About one-third combined width of frontals

8. Frontal contribution to dorsal orbital rim (Modified from Norman, 2004: Character 16; McDonald et al., 2010: Character 68):

8:0. More than half

8:1. Less than half

8:2. Does not contribute

9. Triangular process of the parietal:

9:0. Present

9:1. Absent

10. Ratio of axial lengths of the frontal and the nasal:

10:0. Roughly equal in length

10:1. Nasal is one and one half times length of the frontal

10:2. Nasal is twice length of the frontal

10:3. Nasal is three times length of the frontal

10:4. Nasal is four times length of the frontal

11. Position of nasal contribution to the border of the external naris:

11:0. Posterodorsal border

11:1. Dorsal border

11:2. Does not contribute

12. Nature of the articulation of the nasal, frontal, and prefrontal:

12:0. Nasal overlaps frontal, overlapped by prefrontal

12:1. Nasal overlaps frontal

12:2. Nasal has transverse suture with frontal

12:3. Frontal overlaps nasal

13. Nature of the articulation of the premaxillae with the nasals:

13:0. Nasal processes wedge between nasals

13:1. Nasal overlapped by nasal process of premaxilla

13:2. Tip to tip

13:3. Nasals lie in beveled grooves in lateral surface of nasal processes of premaxilla

13:4. Nasals overlap nasal processes of premaxilla

13:5. Nasal processes split into dorsal and ventral branches, which overlap the nasals

14. Supratemporal fensestra imprints frontal:

14:0. Present

14:1. Absent

15. Lateral suture of the laterosphenoid with the:

15:0. Frontal and postorbital

15:1. Postorbital only

15:2. Frontal only

16. Rugose lateral edge of the postorbital:

16:0. Absent

16:1. Present

17. Parietal contact with the postorbital:

17:0. Present

17:1. Absent

18. Ectopterygoid articulation with the palatine:

18:0. Present

18:1. Absent

19. Ectopterygoid articulation with the jugal (Modified from Norman, 2004: Character 14; McDonald et al., 2010: Character 53):

19:0. Present

19:1. Absent

20. Jugal articulation with the quadrate:

20:0. Absent

20:1. Present

21. Ventral lobe of the jugal (Modified from Norman, 2004: Character 13; McDonald et al., 2010: Character 56):

21:0. Absent

21:1. Present

22. Jugal extends farthest posteriorly in the:

22:0. Quadratojugal process

22:1. Postorbital process

23. Accessory foramen in the quadratojugal (Modified from Norman, 2004: Character 17; McDonald et al., 2010: Character 58):

23:0. Absent

23:1. Present

24. Enclosure of the quadratojugal by the jugal:

24:0. None

24:1. Dorsal

24:2. Dorsal and ventral

25. Quadrate foramen:

25:0. Absent

25:1. Present

26. Quadratojugal size (relative to quadratojugal process of jugal):

26:0. Reduced

26:1. Large

27. Position of the contribution of the lachrymal to the orbital border:

27:0. Anteroventral corner

27:1. Anterior border

27:2. Middle anterior border

28. Contact of the nasal with the lachrymal (Modified from McDonald et al., 2010: Character 50):

28:0. Present

28:1. Absent

29. Shape of the medial lamina of the palatine:

29:0. Fan

29:1. Rectangle

29:2. Triangle

30. Maxillary tooth family count along a single side

31. Maxillary diastema:

31:0. Absent

31:1. Present

32. Lateral process of the maxilla for articulation with the jugal:

32:0. Absent

32:1. Present

33. Jugal articulation with the maxilla:

33:0. Posterior on the latter element

33:1. Displaced forward on the latter element

34. Prefrontal contact with the premaxilla (Modified from McDonald et al., 2010: Character 37):

34:0. Absent

34:1. Present

35. Position of the prefrontal contact with the nasal:

35:0. Anteromedially

35:1. Dorsally

36. Pterygoid contact with the shaft of the quadrate:

36:0. Absent

36:1. Present

37. Quadrate notch (Modified from McDonald et al., 2010: Character 61):

37:0. Absent

37:1. Present

38. Transversely wide ventral quadratic condyle (Modified from Norman, 2004: Character 18; McDonald et al., 2010: Character 64):

38:0. Present

38:1. Absent

39. “Hamalar” process of the head of the quadrate:

39:0. Absent

39:1. Present

40. Contact between paired squamosals on the midline (Modified from McDonald et al., 2010: Character 67):

40:0. Absent

40:1. Present

41. Lateral visibility of anterior process of squamosal:

41:0. Largely obscured

41:1. Prominent across intertemporal bar

Neurocranial Characters:

42. Shape of occipital condyle:

42:0. Subspherical

42:1. Flattened/reniform

43. Supraoccipital participation in the foramen magnum (Modified from McDonald et al., 2010: Character 69):

43:0. Present

43:1. Absent, due to the exoccipital

44. Shape of the cultriform process of the parasphenoid in ventral aspect:

44:0. Elongate

44:1. Triangular

45. Outline shape of the parietal in dorsal aspect:

45:0. Rectangular

45:1. Triangular

46. Ratio of length to the width of the parietal:

46:0. 1:1

46:1. 1.5:1

46:2. 1:1.5

46:3. 1:2

47. Pronounced sagittal crest of the parietal:

47:0. Absent

47:1. Present

48. Interparietal Eminence:

48:0. Present

48:1. Absent

49. Parietal/prootic contact:

49:0. Present

49:1. Absent

50. Crista prootica is comprised of:

50:0. Laterosphenoid/prootic/opisthotic

50:1. Prootic/opisthotic

Mandibular Characters:

51. Dentary diastema (Modified from Norman, 2004: Character 20; McDonald et al., 2010: Character 9):

51:0. Absent

51:1. Present

52. Posteroventral corner of the dentary extends behind coronoid process:

52:0. Absent

52:1. Present

53. Dentary symphysis:

53:0. Set level with tooth row

53:1. Set below tooth row

54. Dorsoventral borders of dentary (Modified from Norman, 2004: Character 22; McDonald et al., 2010: Character 15):

54:0. Thicker posteriorly

54:1. Parallel

54:2. Thicker anteriorly

55. Length of the dentary bearing dentition:

55:0. Full

55:1. 2/3

55:2. Half

56. Orientation of coronoid process of the mandible (Modified from Norman, 2004: Character 23; McDonald et al., 2010: Character 20):

56:0. Posteriorly deflected

56:1. Vertical

56:2. Anteriorly deflected

57. Coronoid bone:

57:0. Present

57:1. Absent

58. Presence of two processes around the Meckelian canal:

58:0. Absent

58:1. Present

59. Presence of shelf between the teeth and the coronoid process (Modified from Norman, 2004: Character 24):

59:0. Absent

59:1. Present

60. Axially flared coronoid process (Modified from McDonald et al., 2010: Character 21):

60:0. Absent

60:1. Present

61. Bifurcate ventral process of the predentary (Modified from Norman, 2004: Character 19; McDonald et al., 2010: Character 2):

61:0. Absent

61:1. Present

62. Character of the occlusal margin of the predentary (Modified from McDonald et al., 2010: Character 4):

62:0. Smooth

62:1. Denticulate

63. Lateral visibility of the angular (Modified from Norman, 2004: Character 26; McDonald et al., 2010: Character 27):

63:0. Visible

63:1. Reduced visibility

63:2. Not visible

64. Nature of articulation of the angular with the surangular (Modified from McDonald et al., 2010: Character 26):

64:0. Angular laterally overlaps surangular

64:1. Groove in ventral surangular

64:2. Angular laterally abuts surangular

65. Anterior extension of the coronoid:

65:0. Present

65:1. Absent

66. Lateral visibility of the coronoid bone:

66:0. Invisible

66:1. Largely visible

66:2. Reduced

67. Splenial coverage of the Meckelian canal:

67:0. Extensive

67:1. Posterior only

68. Presence of the prearticular:

68:0. Present

68:1. Absent

69. Number of surangular foramina (Modified from Norman, 2004: Character 25; McDonald et al., 2010: Character 24):

69:0. Two

69:1. Three

69:2. One

69:3. None

70. Nature of ridges on the teeth (Modified from Norman, 2004: Character 27; McDonald et al., 2010: Characters 85, 90, 91):

70:0. Absent

70:1. Ridge on Dentary teeth

70:2. Ridge on Dentary and Maxillary Teeth

70:3. Ridge on Maxillary with reduced Dentary ridge

70:4. Ridge on Dentary with reduced Maxillary ridge

71. Dentary tooth family count along a single side

Postcranial Characters:

Taken, with modifications, from Norman, 2004.

72. Dorsal neural spines:

72:0. Low and Square

72:1. Rectangular and height more than twice width

72:2. Extremely elongate, height more than six times width

73. Sacrum:

73:0. Seven or fewer vertebrae

73:1. More than seven

74. Scapular blade:

74:0. Straight

74:1. Curved

74:2. Curved and flared distally

75. Scapular acromion:

75:0. Prominent boss on the anterior margin of the scapula

75:1. Boss is reflected laterally

76. Humerus:scapula length:

76:0. Approximately equal lengths

76:1. Scapula longer than humerus

77. Sternal shape:

77:0. Reniform

77:1. Hatchetlike

78. Carpal structure:

78:0. Fully ossified and blocklike

78:1. Reduced

79. Metacarpal I shape:

79:0. Dumbbell-like

79:1. Short and blocklike

79:2. Absent

80. Metacarpals II-IV:

80:0. Dumbbell-like and spreading

80:1. Closely appressed

80:2. Appressed, slender and elongate

81. Manus digit I:

81:0. Present

81:1. Absent

82. Manus ungual I:

82:0. Claw-like

82:1. Conical

82:2. Absent

83. Manus unguals II and III:

83:0. Claw-like

83:1. Flattened, twisted and hoof-like

83:2. Digit II claw-like, Digit III nub

84. Manus digit III:

84:0. Four phalanges

84:1. Three phalanges

85. Preacetabular process of ilium:

85:0. Long and laterally compressed

85:1. Strongly downturned

85:2. Distally twisted

86. Dorsal margin of iliac blade:

86:0. Mostly smooth edged

86:1. Strongly notched behind the ischial peduncle

87. Dorsal edge of ilium above ischial peduncle:

87:0. Not thickened and bevelled

87:1. Thickened

87:2. Everted with pendent tip

88. Ilium, postacetabular process:

88:0. Tapering posteriorly

88:1. Low and rectangular

89. Pubis, prepubic process:

89:0. Short and blunt

89:1. Elongate

90. Pubis, prepubic process:

90:0. Rod-shaped

90:1. Laterally compressed, bar-like

90:2. Short constriction and distal expansion

90:3. Deep expansion

91. Pubic shaft:

91:0. Ends adjacent to distal end of ischium

91:1. Shorter than ischium, no pubic symphysis

92. Ischium, shaft shape:

92:0. Straight

92:1. Arched dorsally

93. Ischium shaft:

93:0. Flattened in cross section

93:1. Rounded in cross section

94. Obturator process of the ischium:

94:0. Absent

94:1. Present near midshaft

94:2. Present and close to pubic peduncle

95. Tip of ischium:

95:0. Unexpanded

95:1. Axial expansion to form a boot

96. Femur:

96:0. Distal half of shaft curved posteriorly

96:1. Straight

97. Femoral fourth trochanter:

97:0. Pendent

97:1. Triangular

97:2. Crested eminence

98. Femur extensor groove:

98:0. Open shallow trough

98:1. U-shaped groove

98:2. Partially enclosed channel

98:3. Fully enclosed tunnel

99. Femur distal condyles:

99:0. Moderately expanded posteriorly

99:1. Expanded posteriorly and anteriorly

100. Metatarsal I:

100:0. Well developed and articulates with phalanges

100:1. Slender and splintlike

100:2. Absent

101. Pedal unguals:

101:0. Elongate and pointed claws

101:1. Elongate but bluntly truncated

101:2. Short, broad and crescentic with reduced or absent claw grooves

APPENDIX 3.

The following is a matrix composed of the states coded for each of 19 ingroup taxa and one outgroup taxon analyzed for each of the characters in Appendix 2. It is available in text and Excel formats.

APPENDIX 4.

The following is a collection of three-dimensional renderings of each of the elements of the skull of OMNH 58340. They are stored as stl files, which can be easily viewed using software freely available for download on the internet (e.g., by searching for "stl file viewer"). 

APPENDIX 5.

The following is the CT data generated for use in this study. The first section (Cranium) comprises scans of the skull, without the mandibles or disarticulated pieces. The second section (Braincase) comprises scans of the braincase section of the cranium, taken at a higher resolution than those for the rest of the skull. Finally, the third section (Miscellaneous) comprises the mandibles and other disarticulated elements (e.g., the right prefrontal and the predentary). Also included are documents detailing the scanning parameters used for each set of scans.