Supplementary information for
A new ceratopsian dinosaur from the Lower Cretaceous of China: implications
for the early evolution of Ceratopsia.
Xing Xu#, Peter J. Makovicky*, Xiao-lin Wang#, Mark A. Norell+, Hai-lu You#
# Institute
of Vertebrate Paleontology and Paleoanthropology, Chinese Academy
of Sciences, Beijing, 100044, P. R. China
*
+
The Field Museum, 1400 S Lake Shore Drive, Chicago IL, 60605
American Museum of Natural History, Central Park West at 79th St., New York, NY
10024
* to whom correspondence should be addressed. Email: xxu@midwest.com.cn
Cladistic Analysis. List of 120 characters and data matrix informative for resolving
the phylogenetic relationships of the taxa in Figure 3. Characters 1-98 are
modified from ref. 19.
Character list
1. Head size small relative to body (0) or large relative to body (1).
2. Head shape in dorsal view: elongate, ovoid (0), or triangular, wide over jugals
(1).
3. Rostral bone forming beak absent (0) or present (1).
4. Rostral ventral process absent (0) or present (1).
5. Anterior face of rostral round, convex (0) or sharply keeled (1).
6. Premaxillary palatal region flat in ventral view (0) or vaulted dorsally (1).
7. Relative height of premaxilla (snout) to orbital region low (0) or deep (1).
8. Convex buccal process anterior to maxillary tooth row formed by premaxilla or
premaxilla and maxilla absent (0) or present (1).
9. Nares position close to buccal margin (0) or dorsal, away from buccal margin (1).
10. Large depression excavating premaxilla anteroventral to naris absent (0) or
present (1).
11. Nasal horn absent (0) small, (1) or large (2).
12. Naris width less than 10% of skull length (0) or more than 10% of skull length
(1).
13. Position of choana on palate: anterior to maxillary tooth row (0) or level with
maxillary tooth row (1).
14. Maxillae from opposite sides separated by vomers at anterior border of the
internal choanae (0) or maxillae contact each other anterior to choanae (1).
15. Dentigerous margin of maxilla straight (0) or ventrally convex (1).
16. Antorbital fossa reduced or absent (0) or large and rounded (1).
17. Palpebral free, articulating with lacrimal (0) or fused to orbital margin (1).
18. Orbit diameter more than 20% of skull length (0) or less than 20% skull length
(1).
19. Epijugal ossification absent (0) or present (1).
20. Epijugal position on jugal: along dorsal edge of horn [epijugal trapezoidal] (0) or
capping end of horn [epijugal conical] (1).
21. Jugal -lacrimal contact reduced (0) or expanded (1).
22. Jugal horns absent (0) or present and laterally directed(1) or present and ventrally
directed (2). .
23. Orbital horns absent (0) or present (1).
24. Postorbital inverted “L”-shaped (0) or triangular and plate like (1).
25. Postorbital with dorsal part rounded and overhanging lateral edge of
supratemporal fenestra (0) or with concave dorsal shelf bordering supratemporal
fenestra (1).
26. Lower temporal opening with postorbital participation in margin (0), postorbital
excluded from margin (1), jugal-squamosal contact very wide and postorbital
situated far from fenestra (2).
.
27. Lower temporal fenestra width more than 10% of skull length (0) or less than
10% of skull length (1).
28. Squamosal subtriangular in lateral view (0) or “T” shaped, with postquadratic
process (1).
29. Temporal bars of squamosals parallel (0) or posteriorly divergent (1).
30. Quadratojugal mediolaterally flattened (0) or transversely expanded and
triangular in coronal section (1) or triangular in coronal section, but with slender
anterior prong articulating with jugal (2).
31. Quadrate shaft anteriorly convex in lateral view (0) or straight (1).
32. Elongate parasagittal process of the palatine absent (0) or present (1).
33. Ectopterygoid exposed in palatal view (0) or reduced and concealed in palatal
view (1).
34. Ectopterygoid contacts jugal (0) or ectopterygoid reduced and restricted to
contact with maxilla (1).
35. Ventral ridge on mandibular process of pterygoid defining “Eustachian canal”
absent (0) or present (1).
36. Pterygoid -maxilla contact at posterior end of tooth row absent (0) or present (1).
37. Parieto-frontal contact flat (0), or depressed (1) or invaginated by fontanelle
(2).
.
38. Parieto-squamosal frill absent (0) or parietal frill less than 70% of basal length of
skull (1) or more than 70% of basal length (2).
.
39. Frill solid (0) or fenestrated near posterior margin (1).
40. Epoccipital ossifications/ frill scallops absent (0) or present (1).
41. Basioccipital participates in foramen magnum (0) or basioccipital is excluded
from foramen magnum and exoccipitals form less than 1/3 of condyle (1) or
exoccipitals form about half or more of occipital condyle (2).
.
42. Basioccipital excluded from basal tubera by basisphenoid and limited to occipital
midline (0) or basioccipital tubera (1).
43. Basipterygoid process orientation anterolateral (0), ventral (1), or posteroventral
(2) when braincase is oriented with condyle pointing posteriorly.
.
44. Basal tubera flat, in plane with basioccipital plate (0) or everted posterolaterally,
forming lip beneath occipital condyle (1).
45. Notch between posteroventral edge of basisphenoid and base of basipterygoid
process deep (0) or notch shallow and base of basipterygoid process close to
basioccipital tubera (1).
46. Exoccipital with three exits for cranial nerves X- XII near occipital condyle (0) or
with two exits (1).
47. Exoccipital - quadrate separated by ventral flange of squamosal (0) or in contact
(1).
48. Paroccipital processes deep (height ≥ 1/2 length) (0) or significantly narrower (1)
49. Supraoccipital participates in dorsal margin of foramen magnum (0) or excluded
from foramen magnum by exoccipitals (1).
50. Supraoccipital anteriorly inclined relative to basioccipital (0) or in same plane as
posterior face of basioccipital (1).
51. Supraoccipital shape tall, triangular (0) or wider than tall, trapezoid (1) or square
(2).
52. Predentary less than 2/3 of dentary length (0) or equal to or more than 2/3 of
dentary length (1).
53. Predentary buccal margin sharp (0) or with a rounded, beveled edge (1) or with
grooved, triturating edge (2).
54. Large pit at anterior end of dentary absent (0) or present (1).
55. Diastema between predentary and first dentary tooth absent (0) or present (1).
56. Ventral margin of dentary curved (0) or straight (1) in lateral view.
57. Contact between dentary and prearticular absent (0) or present (1).
58. Distal end of coronoid process rounded (0) or with anterior expansion (1).
59. Coronoid process positioned close to main axis of dentary and posterior to tooth
row(0) or set lateral to tooth row, and end of tooth row covered by anterior part of
coronoid process (1) or tooth row level with posterior edge of coronoid process
(2).
.
60. Surangular without distinct lateral ridge or shelf overhanging angular (0) or shelf/
ridge present (1).
61. Angular-surangular-dentary contact triradiate (0) or surangular with long ventral
process overlapping angular, dentary-surangular and angular-surangular sutures
form acute angle on lateral face of mandible (1).
62. Posterior end of splenial simple or with shallow dent (0) or with bifid overlap of
angular (1).
63. Three or more teeth in premaxilla (0), or two caniniform teeth in premaxilla (1) or
premaxilla edentulous (2).
.
64. Teeth with single roots (0) with double roots (1).
65. Cheek teeth spaced (0) or closely apressed with determinate eruption and
replacement pattern (1).
66. Teeth occlude at an oblique angle (0) or at a vertical angle (1) or at a vertical
angle but dentary teeth have a horizontal shelf on the labial face (1).
67. Teeth without median primary ridge (0) or with very weak and wide median ridge
on maxillary teeth (1) or both maxillary and dentary teeth with distinct primary
ridge (2).
.
68. Base of primary ridge confluent with the cingulum on maxillary teeth (0) or base
of primary ridge set back from cingulum, which forms a continuous ridge at the
crown base (1).
69. Tooth row double, with only one replacement tooth present at a time (0) or
battery-like with multiple (≥3) rows of replacement teeth (1).
70. Both lingual and buccal sides of teeth covered with enamel (0) or enamel
restricted to lateral side of maxillary and medial side of dentary teeth (1).
71. Dentary tooth crowns with continuous, smooth root crown transition (0), or
bulbous expansion at root-crown transition on labial side of tooth.
72. Number of alveoli in dentary less than 20 (0) or more than 20 (1).
73. Cheek teeth with cylindrical roots (0) or roots with anterior and posterior grooves
along root (1).
74. Tooth crowns radiate or pennate in lateral view (0) or crowns ovate in lateral
view (1).
75. Atlas intercentrum semicircular (0) or disc shaped (1).
76. Atlas intercentrum not fused to odontoid (0) or fused (1).
77. Atlas neurapophyses free (0) or fused to intercentrum/ odontoid (1).
78. Axial neural spine low (0), or tall and hatchet-shaped (1), or elongate and
posteriorly inclined (2).
.
79. Syncervical absent (0) partially fused [centra but not arches] (1) or completely
coossified (2).
.
80. Dorsal vertebrae with flat articulations on zygapophyses (0) or tongue and groove
articulations on zygapohyses (1).
81. Number of sacrals: five (0) or six (1) or seven (2) or eight or more (3).
.
82. Outline of sacrum defines rectangle or hourglass in dorsal view (0) or oval in
dorsal view (1).
83. Caudal neural spines short and inclined (0) or tall and straight (1).
84. Distal chevrons with lobate expanded shape (0) or rod-like (1).
85. Clavicles absent (0) or present and robust
(1)
86. Scapula distinctly curved in sagittal view (0) or relatively flat (1).
87. Scapular blade at acute angle relative to glenoid (0) or almost perpendicular to
glenoid (1).
88. Olecranon process relatively small (0) or enlarged (≥ 1/3 of ulnar length) (1).
89. More than two distal carpals (0) or less than two distal carpals (1).
90. Manus much smaller than pes (0) or closer to pes in size (1).
91. Shaft of postpubis round (0) or mediolaterally flattened, blade like(1) in cross
section.
92. Postpubis long and ventrally oriented (0) or short and posteriorly directed (1).
93. Prepubis short and rod-shaped (0) or long and flared at anterior end (1).
94. Ischial shaft straight (0) or curved, posterodorsally convex (1).
95. Femoral fourth trochanter large and pendant (0) or reduced (1).
96. Tibio-femoral ratio more than one (0) or less than one (1).
97. Foot gracile with long, constricted metatarsus, elongate phalanges (0) or short and
uncompressed, stubby phalanges (1).
98. Pedal unguals pointed (0) or moderately rounded, hoof-like (1).
99. Preorbital region more than 40% (0), less than 40% the length of the skull
100.Ventral border of external nares significantly below (0); about the level of (1) or
significantly above (2) that of the infratemporal fenestra.
.
101.Premaxilla-maxilla ventral margin relatively straight (0), sinuous (1)
102.Premaxilla-prefontal contact absent (0); present (1)
103.Anterior end of the nasal above (0); below and far rostral to the (1) the external
naris.
104.Eminence on the rim of the buccal emargination of the maxilla near the junction
with the jugal absent (0); present (1)
105.Distinctive indentation on midline of the posterior parietals present (0); absent (1)
106.Prominent posterior process on pterygoid absent (0); present (1)
107.Pterygoid mandibular process short (0); long (1)
108.Pterygoid mandibular process formed only by pterygoid (0); jointly by pterygoid
and ectopterygoid (1).
109.A ventral flange on dentary absent (0); present (1).
110.Prominent medial expansion on the central mandible absent (0); present (1).
111.Retroarticular process long (0); short or absent (1)
112.The neural spine of the axis anteroposteriorly short (0); long, extending caudally
to the posterior end of the centrum of the succeeding cervical (1).
113.Predentary with rounded anterior margin and distally broad posteroventral
process (0); with point anterior margin and distally narrow posteroventral process
(1).
114.Temporal process of squamosal simple (0) or deeply bifurcate around temporal
process of postorbital.
115.Posterior edge of squamosal angled anteromedially (0) or posteromedially,
squamosal contributing to frill margin (1).
116.Lateral surface of surangular flat or only weakly convex (0) or with pronounce
laterally convex curvature (1).
117.Tip of rostral level with maxillary tooth row (0) or dorsal to maxillary tooth row
(1).
118.Cingula on cheek teeth absent (0)or present (1).
119.Tab on surangular forming lateral wall to glenoid absent (0)or present (1).
120. Tip of predentary flat (0) or upturned (1)
Data matrix
Hypsilophodon foxi
000--00000000001000-000000000000000000-0000001?10000000110000000000001
00000000000000?0000000000010001000001100001000-000
Stegoceras validus
000--00000000000100-100--0100?0?002000-000000-000000?001000000000000010
000??0??10????000?0???01010000000011100?00010-00Archaeoceratops oshimai
111111111000??0100100101?110011??????1??11101?0100101?01?011??000010???0
?1000?01000?????????00??10001000?11?011?10-10111
Asiaceratops salsopaludalis
??1??1??10????01????????????????????????11?00????????001???0??2000?001001??
???????1???1??????????0???????????????--0-01Bagaceratops rozhdestvenskyi
11111111101?010100110101010112110011??101110100100111011101111200020000
011?????????????????0??????0??00011??0?111011-111
Chaoyangsaurus youngi
111001?010????0??00-?0????0??0????00????01?0???????00101?000??10000001000
000000???????????????????121??1?01000101--00001
Centrosaurus apertus
1111111101211100111112110211111?111122112110111011202011112000211120100
111111220310110111111111101011000?1000?1110110111
Leptoceratops gracilis
111111111000011100100101100001100?11010011?100110101110010100020022101
101101011010110110000000001002100001?1011111111111
Graciliceratops gobiensis
11??????????0????0???1?????1111???????10?1?????????????1?011???000200?00???
????1??1??1?????0??0010??????0????????011-11Montanoceratops cerorhynchus
1?????1?1???0?010?10?1011??0?11?????0???112100??010????1101??0?002210?101
10111112011011?0000000010??????????????1111-11Protoceratops andrewsi
111111111010010100110101010112110011?210111010010011101010111110002000
00110111112011011000100000110200000/111?011110111111
Psittacosaurus mongoliensis
1110011010001100000-01000000000010010100010000010010000100100?2000000
100000000000000?11000000000101211111111100100000000
Triceratops horridus
11111110012111001111121102111110111122012110111011202011112000211120100
11?11122031011011111111110101100011?00?1110111111
Udanoceratops tshizhovi
1?111110100?0?1???10?1???????11??????????????????????1?0?0100020022100101
1?????0201??110??????0????????????????-1--1111Zuniceratops christopheri
??????????????0??????11??????????????????1?????????????1?0?????0?12000?01???
??????0??????????1???????????????????----1-Liaoceratops yanzigouensis
?111?11010000101000-01010100001?00?001?0011010?100100001001001000010?0
0001????????????????????????0011011111111??1110001
Psittacosaurus sinensis
111001101000--00000-01000000000-00--0100-------0---00001-0100-200-0-0--000--0
00-100----0------0-001211101-1-000100000000
The data matrix was analysed cladistically using the NONA (ver 2.0) software
package (Goloboff, 1993) and formatting and character exploration was performed in
WinClada (Nixon, 2000). All characters were weighted equally and treated as
unordered.
The analysis protocol consisted of 1000 Tree Bisection and Regrafting
tree searches followed by branch swapping. Settings included collapsing unsupported
branches and counting all states in polymorphic codings. Hypsilophodon foxi and
Stegoceras validus were employed as outgroups, and trees were rooted on
Hypsilophodon foxi.
Software references:
Goloboff, P. A. 1993. NONA (ver 2.0) published by the author, S. M. de Tucuman,
Argentina.
Nixon, K. C. 1999. Winclada (BETA) ver. 0.9.9 published by the author, Ithaca, New
York, USA.
Both packages available from http://www.cladistics.org.
Remarks on phylogenetic results:
Several named basal neoceratopsians were excluded from this analysis, because they
are undiagnostic (Turanoceratops tardabilis, Kulceratops kulensis) or appear to be a
junior synonym of another taxon (Breviceratops kozlowskii4). The taxon
Asiaceratops salsoplaudalis is potentially diagnostic, if all referred elements can be
shown to pertain to one taxon. Codings for Graciliceratops gobiensis are based only
on ZPAL (Zaklad Paleobiologi, Warsaw) MgD I/156, which can be distinguished from
other neoceratopsians based on differential diagnoses, but not autapomorphy.
Ordering of some characters, particularly chars. 63 and 100 leads to an alternate
position for Chaoyangsaurus youngi as the most basal member of the Psittacosauridae.
These ordering assumptions dictate topology here, but in the absence of compelling
ontogenetic or other data that may indicate directional transitions between character
states, these assumptions are difficult to defend. We therefore chose to unorder all
characters.
Chaoyangsaurus has been proposed as the most basal neoceratopsian, as
a possible basal psittacosaurid, or as basal to a clade composed of both these groups.
Although Chaoyangsaurus has two putative neoceratopsian synapomorphies (reduced
retroarticular process, upturned predentary), other neoceratopsian or
psittacosaurid-neoceratopsian synapomorphies (keeled rostral and predentary, jugal
horn, coronoid process lateral to mandibular tooth row) are not present (contra4).
Table 1.
Length
measurements
(millimeters) and ratios
in
Liaoceratops
yanzigouensis.
L. yanzigouensis L.yanzigouensis
IVPP V12633
IVPP V12738
Basal skull length
77
Total skull length (tip to midline of 101
posterior paritals)
Mandible length
78
Preorbital length
41
Maximum external naris diameter
8
Maximum orbital diameter
25
Ratios
Snout/skull
0.53
Orbit/skull
0.32
Naris/skull
0.10
111
154
116
65
21
36
0.59
0.32
0.19