Supplementary Information to be made available on Nature’s Web site
The phylogenetic analysis was constructed by scoring the following characters from Chiappe et al., 1998 in Caudipteryx and Protarchaeopteryx.
1. Rostral portion of premaxillae unfused (0) or fused (1) in adults.
2. Frontal process of premaxilla short (0), relatively long to very long, at least approaching the rostral border of the antorbital fossa (1).
3. Cup-shaped caudal maxillary sinus: absent (0), present (1).
4. Caudal margin of naris farther rostral than (0) or, nearly reaching or overlapping (1) the, rostral border of the antorbital fossa.
5. Triradiate palatine (jugal process absent): absent (0), present (1).
6. Postorbital-jugal contact: present (0), absent (1).
7. Quadratojugal sutured to the quadrate (0), or joined by a ligament (1).
8. Quadratojugal-squamosal contact: present (0), absent (1).
9. Quadrate articulating only with the squamosal (0), or with both prootic and squamosal (1).
10. Caudal tympanic recess opens on the rostral margin of the paraoccipital process (0), or into the columellar recess (1).
11. Coronoid bone: present (0), absent (1).
12. Teeth in adults: with serrated crown (0) or unserrated crowns (1).
13. One or more pneumatic foramina piercing the centra of mid-anterior cervicals beyond the level of the parapophysis-diapophysis: present (0), absent (1).
14. Anterior cervical vertebrae heterocoelous: absent (0), present (1).
15. Carotid processes in intermediate cervicals: absent (0), present (1).
16. Prominent ventral processes on cervico-dorsal vertebrae: absent (0), present (1).
17. Cervico-dorsal vertebrae with parapophyses located at the same level as the prezygapophyses: absent (0), present (1).
18. Wide vertebral foramen in thoracic vertebrae, vertebral foramen/articular cranial facies ratio (vertical diameter) larger than 0.40: absent (0), present (1).
19. Hyposphene-hypantrum accessory intervertebral articulations in dorsal vertebrae: present (0), absent (1).
20. Synsacrum formed by 7 or fewer (0), or 8 or more vertebrae (1).
21. Cranial articular surface of synsacrum strongly concave: absent (0), present (1).
22. Caudal portion of the synsacrum forming a prominent ventral keel: absent (0), present (1).
23. Caudal articular surface of synsacrum convex: absent (0), present (1).
24. Prezygapophyses of distal caudal vertebrae: elongate (0), short or absent (1).
25. Caudal vertebrae: amphicoelous (0), or procoelous (1).
26. First caudal centrum strongly compressed ventrally: absent (0), present (1).
27. Elongated (much longer than wider) proximal haemal arches: absent (0), present (1).
28. Pygostyle: absent (0), present (1).
29. Caudal vertebral count larger than 35 (0) or fewer than 25-26 (1).
30. Coracoid and scapula articulate through a broad, sutured articulation (0), or through more localize, less extensive facets (1).
31. Scapula articulated at the shoulder (proximal) end of coracoid (0), or well below it (1).
32. Coracoid and scapula placed in the same plane (0), or forming a sharp angle (1) at the level of the glenoid cavity.
33. Coracoid shape: elongated with subrectangular profile (0), short (1), strut-like (2).
34. Bicipital tubercle (= acrocoracoidal process): present (0), absent (1).
35. Supracoracoid nerve foramen of coracoid centrally located (0), or displaced (often as an incision or even without passing through) toward the medial margin of coracoid (1).
36. Scapular caudal end blunt and usually expanded (0), or tapered to sharp point (1).
37. Prominent acromion in the scapula: absent (0), present (1).
38. Boomerang-shaped furcula, with interclavicular angle approximately 90_ (0), or U-shaped furcula, with an interclavicular angle less than 70_ (1).
39. Sternum subquadrangular to transversally rectangular (0) or longitudinally rectangular (1).
40. Ossified sternal keel: absent (0), present (1).
41. Proximal and distal humeral ends twisted (0), or expanded nearly in the same plane (1).
42. Ventral tubercle of humerus projected ventrally (0), proximally (1), or caudally, separated from the humeral head by a deep capital incision (2).
43. Humerus with distinct transverse ligamental groove: absent (0), present (1).
44. Humeral pneumatic fossa: absent (0), present (1).
45. Humeral distal condyles mainly located on distal (0), or cranial (1) aspect.
46. Humerus with two (0), or a single distal condyle (1).
47. Well-developed olecranal fossa on the caudal face of the distal end of humerus: absent (0), present (1).
48. Ulna shorter than (0), or subequal in length to, or longer than, humerus (1).
49. Diameter of ulnar shaft: radial shaft/ulnar shaft ratio larger (0), or smaller (1) than 0.70.
50. Olecranon process on ulna: relatively small (0), hypertrophied, nearly one-third (1) or one-half (2) the length of the ulna.
51. Distal end of ulna subrectangular and transversely compressed (0), or subtriangular in shape (1).
52. Semilunate ridge on ulnar dorsal condyle: absent (0), present (1).
53. Ulnare (scapholunar) of round to sub-rectangular shape (0) or U-shaped to heart-shaped (1).
54. Distal carpals and proximal portion of metacarpals unfused (0), or fused forming a carpometacarpus (1).
55. Extensor process on carpometacarpus: absent or rudimentary (0), present (1).
56. Alular metacarpal (I)/major metacarpal (II) length ratio smaller than or equivalent to 0.30: absent (0), present (1).
57. Alular metacarpal massive, depressed, and quadrangular-shaped: absent (0), present (1).
58. Alular digit (I) long, exceeding the distal end of the major metacarpal (0), or
short, not surpassing this metacarpal (1).
59. Alular digit (I) large, robust, and dorsoventrally compressed: absent (0), present (1).
60. Prominent ventral projection of the latero-proximal margin of the proximal phalanx of alular digit (digit I): absent (0), present (1).
61. Alular ungual phalanx with two, ventro-proximal foramina: absent (0), present (1).
62. Pelvic elements unfused (0), or fused or partially fused (1).
63. Pubis subvertically oriented (0), or well-retroverted (1).
64. Prominent antitrochanter: absent (0), caudally directed (1), or dorso-caudally directed (2).
65. Iliac fossa for M. cuppedicus (=M. iliofemoralis internus): present (0), absent or rudimentary (1).
66. Iliac brevis fossa: present (0), absent (1).
67. Pubic pedicel ventrally or caudoventrally (0), or cranioventrally projected (1).
68. Supracetabular crest on ilium absent or rudimentary (0), extending throughout the acetabulum (1), or extending only over the rostral half of the acetabulum (2).
69. Ischiadic terminal processes in contact (0), or lacking contact (1).
70. Ischium less than two-thirds (0), or two-thirds or more of pubis length (1).
71. Obturator process of ischium: prominent (0), or reduced or absent (1).
72. Pubic apex in contact (0), or lacking contact (1).
73. Pubis shaft laterally compressed throughout its length: absent (0), present (1).
74. Pubic foot: present (0), absent (1).
75. Pubic apron more than one-third the length of the pubis (0), shorter or absent (1).
76. Laterally compressed and kidney-shaped proximal end of pubis: absent (0), present (1).
77. Femur with distinct fossa for capital ligament: absent (0), present (1).
78. Femoral anterior trochanter nearly confluent with the greater trochanter (0), or fused to it forming the trochanteric crest (1).
79. Femoral posterior trochanter: present (0), absent (1).
80. Conical and strongly distally projected lateral condyle of femur: absent (0), present (1).
81. Femoral popliteal fossa distally bounded by a complete transverse ridge: absent (0), present (1).
82. Tibiofibular crest on the lateral condyle of femur: absent (0), present (1).
83. Tibia, calcaneum, and astragalus unfused or poorly coosified (sutures still visible) (0), or complete calcaneo-astragalar-tibial fusion (1).
84. Medial border of tibiotarsus at nearly the level of lateral border (0) or strongly projected proximally (1).
85. Proximal end of fibula prominently excavated by a medial fossa (0), or nearly flat (1).
86. Fibula with tubercle for M. iliofibularis anterolaterally (0), laterally or caudolaterally or caudally (1) directed.
87. Fibula reaching the proximal tarsals (0), or greatly reduced distally, without reaching these elements (1).
88. Distal tarsals free (0), or completely fused to the metatarsals (1).
89. Metatarsal V: present (0), absent (1).
90. Proximal end of metatarsal III in the same plane as metatarsals II and IV (0), reduced, not reaching the tarsals (arctometatarsalian condition) (1), or plantarily displaced with respect to metatarsals II and IV (2).
Character Matrix modified from Chiappe et al., 1998.
Velociraptor 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
Archaeopteryx 01011?11?11100?00??00?010?001000000010??0000000000000001000000000?00?0100000?000?000??0000
Mononykus ?????????1?11011111?111?11???00011000?11110011000210?100101111?11?12???????1011100011?1??1
Shuvuia 00?0111111110011111011111110100011000?11110011000210?10010111?11101211111111??1?0?01111001
Enantiornithines 11111111??111111011110010001111120111111021110111011111101000112010001000010110011101?1110
Ornithurae 111111111111111101110001000111112011111112111011101111110100?11211001111111011101110111112
Protarchaeopteryx 00????0?0??0?0???0?0000?0?0010000????000???0???0100??0000000000????????00?00?0??0?00?????0
Caudipteryx 01?1?0000??1?0???0?0????00001???0??0??00???0??0010000000000000000?00??000?0?00??0?00??00?0
Diagnoses of the Chuniaoae and the Avialae under alternative optimizations. Characters marked with a * are ambiguous due to missing data.
Delayed TransformationAccelerated Transformation
Unnamed clade of Caudipteryx + Avialae
2 0-120-1
4*0-14*0-1
120-15*0-1
10* 0-1
11*0-1
120-1
15*0-1
19*0-1
24*0-1
37*0-1
69*0-1
85*0-1
86*0-1
Avialae5*0-16*0-1
70-170-1
80-180-1
10*0-19*0-1
11*0-118*0-1
24*0-139*0-1
710-140*0-1
56*0-1
710-1
References
Chiappe, L.M., M.A. Norell, and J.M. Clark. 1998. The skull of a relative of the stem-group bird Mononykus. Nature 392:275-278.