824:
2420:
2336:
2172:
2244:
804:
2385:, despite the fact that these genera vary with respect to the size and architecture of their domes, and fact that they existed during varying geologic periods. These findings were in stark contrast with the results from analysis of the relatively flat-headed pachycephalosaurids, where there was an absence of pathology. This would support the hypothesis that these individuals represent either females or juveniles, where intra-specific combat behavior is not expected.
113:
154:
912:
4648:
4671:
2389:
2327:
2316:
2558:
2307:
2381:, an infection of the bone resulting from penetrating trauma, or trauma to the tissue overlying the skull leading to an infection of the bone tissue. This high rate of pathology lends more support to the hypothesis that pachycephalosaurid domes were employed in intra-specific combat. The frequency of trauma was comparable across the different genera in this
1056:. In 2006, Robert Sullivan published a re-evaluation of pachycephalosaur taxonomy. Sullivan considered attempts by Maryańska and Osmólska to restrict the definition of Pachycephalosauria redundant with their Pachycephalosauridae, since they were diagnosed by the same anatomical characters. Sullivan also rejected attempts by
1075:
Sullivan diagnosed the
Pachycephalosauridae-based only on characters of the skull, with the defining character being a dome-shaped frontoparietal skull bone. According to Sullivan, the absence of this feature in some species assumed to be primitive led to the split in classification between domed and
2433:
The Asian and North
American species of pachycephalosaurs lived in markedly different environments. Asian specimens are normally more intact, indicating they were not transported far from their place of death before fossilization. They likely lived in a large desert region in central Asia with a hot
2233:
Also, the rounded shape of the skull would lessen the contacted surface area during head-butting, resulting in glancing blows. Other possibilities include flank-butting, defense against predators, or both. The relatively wide build of pachycephalosaurs (which would protect vital internal organs from
2162:
has been found, mandibular teeth are similar in size and shape to those in the upper jaw. Wear patterns on the teeth vary by species, indicating a range of food preferences which could include seeds, stems, leaves, fruits, and possibly insects. A very wide rib cage and large gut cavity extending all
2277:
instead argued that the dome functioned for species recognition. There is evidence that the dome had some form of external covering, and it is reasonable to consider the dome may have been brightly covered, or subject to change color seasonally. Due to the nature of the fossil record, however, it
2229:
Anatomical evidence for combative behavior includes vertebral articulations providing spinal rigidity, and the shape of the back indicating strong neck musculature. It has been suggested that a pachycephalosaur could make its head, neck, and body horizontally straight, in order to transmit stress
719:
animals with thick skulls. Skulls can be domed, flat, or wedge-shaped depending on the species, and are all heavily ossified. The domes were often surrounded by nodes and/or spikes. Partial skeletons have been found of several pachycephalosaur species, but to date no complete skeletons have been
2284:
argued that species recognition is an unlikely evolutionary cause for the dome, because dome forms are not notably different between species. Because of this general similarity, several genera of
Pachycephalosauridae have sometimes been incorrectly lumped together. This is unlike the case in
1008:' as a basal grouping within Pachycephalosauria, paraphyletic with respect to the traditional, dome-headed pachycephalosaurs. The same conclusion had previously been reached by George Olshevsky in 1991, who classified heterodontosaurids as basal pachycephalosaurs on the basis of perceived
880:. In some species this takes the form of a raised dome; in others, the skull is flat or wedge-shaped. While the flat-headed pachycephalosaurs are traditionally regarded as distinct species or even families, they may represent juveniles of dome-headed adults. All display highly ornamented
2442:. Specimens are far less intact; usually only skull caps are recovered, and those found regularly exhibit surface exfoliation and other signs that they were transported long distances by water before fossilization. It is assumed that they lived in the mountains in a
2258:
argued against the battering ram hypothesis. They argued that the dome was "an ephemeral ontogenetic stage", the spongy bone structure could not sustain the blows of combat, and the radial pattern was simply an effect of rapid growth. Later biomechanical analyses by
1080:) show this distinction to be incorrect. Sullivan also pointed out that the original diagnosis of Pachycephalosauridae centered around "flat to dome-like" skulls, so the flat-headed forms should be included in the family. In a paper published in 2003,
3287:
Woodruff, D. Cary; Schott, Ryan K.; Evans, David C. (2023-11-15). "Two new species of small‐bodied pachycephalosaurine (Dinosauria, Marginocephalia) from the uppermost
Cretaceous of North America suggest hidden diversity in well‐sampled formations".
2230:
during ramming. However, in no known dinosaur could the head, neck, and body be oriented in such a position. Instead, the cervical and anterior dorsal vertebrae of pachycephalosaurs show that the neck was carried in an "S"- or U-shaped curve.
2136:
The small size of most pachycephalosaur species and lack of skeletal adaptation indicates that they were not climbers and primarily ate food close to the ground. Mallon et al. (2013) examined herbivore coexistence on the island continent of
2153:
teeth. Front teeth are small and peg-like with an ovular cross section and were most likely used for grabbing food. In some species, the last premaxillary tooth was enlarged and canine-like. Back teeth are small and triangular with
1758:
and Early
Cretaceous pachycephalosaur fossils, even though they should have existed if the modern understanding of ornithischian phylogeny is correct. However, this hypothesis has not been widely accepted by other paleontologists.
2407:(2013) concluded that, taken together, the frequency of lesion distribution and the bone structure of frontoparietal domes lend strong support to the hypothesis that pachycephalosaurids used their unique cranial structures for
2197:
The adaptive significance of the skull dome has been heavily debated. The popular hypothesis among the general public that the skull was used in head-butting, as sort of a dinosaurian battering ram, was first proposed by
2462:
and central Asia. Pachycephalosaurs originated in Asia and had two major dispersal events, resulting in the two separate waves of pachycephalosaur evolution observed in Asia. The first, occurring before the late
849:
characterized by their thickened skulls. They had a bulky torso with an expanded gut cavity and broad hips, short forelimbs, long legs, a short, thick neck, and a heavy tail. Large orbits and a large
1072:), while leaving more "basal" species outside that family in Pachycephalosauria. Therefore, Sullivan's use of Pachycephalosauridae is equivalent to Sereno and Benton's use of Pachycephalosauria.
857:
indicate that they had a good sense of smell relative to other dinosaurs. They were fairly small dinosaurs, with most falling in the range of 2–3 meters (6.6–9.8 feet) in length and the largest,
1118:, which has been modified in many iterations to include newer taxa and additional characters. The version of the analysis published by Woodruff and colleagues in 2023 is below.
2982:
2141:, during the Late Cretaceous and concluded that pachycephalosaurids were generally restricted to feeding on vegetation at, or below, the height of 1 meter. They exhibit
2603:
Fonseca, A. O.; Reid, I. J.; Venner, A.; Duncan, R. J.; Garcia, M. S.; Müller, R. T. (2024). "A comprehensive phylogenetic analysis on early ornithischian evolution".
4146:
3080:
864:
estimated to measure 4.5 meters (14.8 feet) long and weigh 450 kilograms (990 pounds). The characteristic skull of pachycephalosaurs is a result of the fusion and
3923:
Lehman, TM (2010). "Pachycephalosauridae from the San Carlos and Aguja
Formations (Upper Cretaceous) of west Texas, and observations of the frontoparietal dome".
2732:"Description and revised diagnosis of Asia's first recorded pachycephalosaurid, Sinocephale bexelli gen. nov., from the Upper Cretaceous of Inner Mongolia, China"
3535:
Lehman TM (2010). "Pachycephalosauridae from the San Carlos and Aguja
Formations (Upper Cretaceous) of west Texas, and observations of the frontoparietal dome".
4169:
4277:
3211:(2010). "Texacephale langstoni, a new genus of pachycephalosaurid (Dinosauria: Ornithischia) from the upper Campanian Aguja Formation, southern Texas, USA".
930:
Most pachycephalosaurid remains are not complete, usually consisting of portions of the frontoparietal bone that forms the distinctive dome. This can make
4799:
4794:
4044:"Common Functional Correlates of Head-Strike Behavior in the Pachycephalosaur Stegoceras validum (Ornithischia, Dinosauria) and Combative Artiodactyls"
892:
in the form of blunt horns and nodes. Many species are only known from skull fragments, and a complete pachycephalosaur skeleton is yet to be found.
938:
relies almost entirely on cranial characteristics. Consequently, improper species have historically been appointed to the clade. For instance,
3832:"Cranial histology of pachycephalosaurs (Ornithischia: Marginocephalia) reveals transitory structures inconsistent with head-butting behavior"
3495:"Cranial histology of pachycephalosaurs (Ornithischia: Marginocephalia) reveals transitory structures inconsistent with head-butting behavior"
4664:
3755:
3041:
2571:
3769:
3451:
2293:
argued that instead the dome had a mechanical function, such as combat, one which was important enough to justify the resource investment.
2377:
studied cranial pathologies among the
Pachycephalosauridae and found that 22% of all domes examined had lesions that are consistent with
1114:
either just outside or just within the clade of it and more derived pachycephalosaurs. These studies began with the phylogenetic work of
4784:
3696:; Martill, D.M. (2008). "Dinosaurs of Great Britain and the role of the Geological Society of London in their discovery: Ornithischia".
4789:
2694:
3364:"Feeding height stratification among the herbivorous dinosaurs from the Dinosaur Park Formation (upper Campanian) of Alberta, Canada"
3669:
2820:
1076:
non-domed pachycephalosaurs; however, discovery of more advanced and possibly juvenile pachycephalosaurs with flat skulls (such as
3113:
2399:
Histological examination reveals that pachycephalosaurid domes are composed of a unique form of fibrolamellar bone which contains
4270:
3964:, a new genus of pachycephalosaurid (Dinosauria: Ornithischia) from the upper Campanian Aguja Formation, southern Texas, USA".
325:
153:
4157:
3095:
3585:"Distributions of Cranial Pathologies Provide Evidence for Head-Butting in Dome-Headed Dinosaurs (Pachycephalosauridae)"
2888:
2844:
Stocker, M.R.; Nesbitt, S.J.; Criswell, K.E.; Parker, W.G.; Witmer, L.M.; Rowe, T.B.; Ridgely, R.; Brown, M.A. (2016).
4263:
4779:
4674:
4245:
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2403:
that play a critical role in wound healing, and are capable of rapidly depositing bone during remodeling. Peterson
299:
2271:
argued that the growth patterns discussed by
Goodwin and Horner are not inconsistent with head-butting behavior.
4208:
3850:
3513:
3172:
3129:
2240:(which would have been used to great effect during flank-butting) add credence to the flank-butting hypothesis.
4368:
3240:"The oldest North American pachycephalosaurid and the hidden diversity of small-bodied ornithischian dinosaurs"
2155:
1231:
4647:
2954:
Dieudonné PE, Cruzado-Caballero P, Godefroit P, Tortosa T (2020). "A new phylogeny of cerapodan dinosaurs".
2641:
823:
364:
331:
4729:
4097:"Society of Vertebrate Paleontology Meeting: Did Horny Young Dinosaurs Cause Illusion of Separate Species?"
2659:
4691:
4195:
Williamson, TE; Carr, TD (2002). "A new genus of derived pachycephalosaurian from western North
America".
4170:"A new pachycephalosaurid from the Baynshire Formation (Cenomanian-late Santonian), Gobi Desert, Mongolia"
1081:
895:
Members of Pachycephalosauria characteristically have an unusually domed head reminiscent of the earlier
4751:
4395:
3770:"Agonistic behavior in pachycephalosaurs (Ornithischia:Dinosauria): a new look at head-butting behavior"
3452:"Agonistic behavior in pachycephalosaurs (Ornithischia:Dinosauria): a new look at head-butting behavior"
3159:
Williamson TE, Carr TD (2002). "A new genus of derived pachycephalosaurian from western North America".
1754:
with respect to pachycephalosauria. This analysis was proposed as a hypothesis for the complete lack of
2419:
1094:, made up of "all other dome-headed pachycephalosaurians; this was referred to as Pachycephalosaurinae
2335:
2171:
962:, another dinosaur initially described as a pachycephalosaurid, has also since been reclassified as a
4738:
4542:
4490:
4055:
3883:
3802:
3705:
3596:
3251:
2908:
900:
3989:
3985:
3657:
3007:
3003:
2243:
1747:
1005:
700:
2846:"A Dome-Headed Stem Archosaur Exemplifies Convergence among Dinosaurs and Their Distant Relatives"
4593:
4220:
4124:
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3344:
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148:
134:
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as one of the earliest fully-domed members, with flat-headed and potentially juvenile taxa like
803:
768:
might also represent a basal pachycephalosaur. The oldest known definitive pachycephalosaur is
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4083:
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3911:
3765:
3751:
3675:
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3037:
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2826:
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2700:
2690:
2443:
1885:
1833:
1746:
Below is a cladogram published by Dieudonné and colleagues (2020) which controversially found
911:
2438:. North American specimens are typically found in rocks that were formed by erosion from the
1064:
studies, to re-define Pachycephalosauridae to include only "dome-skulled" species (including
4204:
4108:
4073:
4063:
3973:
3932:
3901:
3891:
3846:
3713:
3614:
3604:
3544:
3509:
3385:
3375:
3336:
3297:
3259:
3220:
3168:
3125:
2983:"A Revision of the Parainfraclass Archosauria Cope, 1869, Excluding the Advanced Crocodylia"
2963:
2926:
2916:
2857:
2778:
2769:(Ornithischia: Ceratopsia) from the Upper Jurassic Shishugou Formation of Xinjiang, China".
2739:
2731:
2612:
2563:
2382:
1040:, the Pachycephalosauridae. Later researchers, such as Michael Benton, have ranked it as an
1037:
975:
889:
761:
747:
733:
601:
4096:
4572:
4353:
4337:
2804:
2439:
1346:
1041:
1025:
1009:
775:
756:
730:
692:
477:
353:
278:
3642:
Reid, R.E.H. (1997). "Histology of bones and teeth". In Currie, P.J.; Padian, K. (eds.).
2522:. Two species originally reported to be pachycephalosaurs discovered outside this range,
754:, although R.M. Sullivan has doubted that either of these species are pachycephalosaurs.
4059:
3887:
3709:
3600:
3255:
2912:
4503:
4471:
4249:
4136:
Sues, H-D (1978). "Functional morphology of the dome in pachycephalosaurid dinosaurs".
4078:
4043:
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3743:
3619:
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3390:
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3029:
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2809:
2435:
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on the front and back of the crown, used for mouth processing. In species in which the
1197:
1102:
Phylogenetic analyses by many authors have found Pachycephalosauria to be a group with
885:
854:
724:
396:
305:
230:
4018:
3831:
3494:
3417:
2630:
699:
Period, dating between about 85.8 and 66 million years ago. They are exclusive to the
4773:
4621:
4586:
4558:
4479:
3952:
3725:
3564:
3348:
2790:
2751:
2534:
2510:, and involved a migration back into Asia from North America by a common ancestor of
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2425:
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2352:
2219:
2023:
1958:
1850:
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1435:
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952:
945:
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896:
873:
811:
704:
681:
673:
568:
537:
497:
375:
140:
70:
4224:
4128:
3858:
3521:
3188:
3145:
2218:. In this hypothesis, pachycephalosaurs rammed each other head-on, as do modern-day
2210:. Many paleontologists have since argued for the head-butting hypothesis, including
934:
identification a difficult task, as the classification of genera and species within
17:
4607:
4380:
4328:
3814:
3693:
3208:
2512:
2495:
2183:
2006:
1751:
1411:
1061:
1029:
869:
865:
846:
517:
314:
214:
128:
4112:
3977:
3340:
3324:
3224:
2967:
2782:
2616:
2388:
695:. With the exception of two species, most pachycephalosaurs lived during the Late
4068:
4019:"Structural mechanics of pachycephalosaur crania permitted head-butting behavior"
3896:
3609:
3418:"Structural mechanics of pachycephalosaur crania permitted head-butting behavior"
3362:
Mallon, Jordan C.; Evans, David C.; Ryan, Michael J.; Anderson, Jason S. (2013).
2921:
2163:
the way to the base of the tail suggests the use of fermentation to digest food.
4723:
4628:
4614:
4600:
4579:
4565:
4531:
4510:
4001:
3057:
2524:
2518:
2489:
2477:
2400:
2346:
2326:
2236:
2189:
2175:
Hypothetical examples of pachycephalosaur combat behavior, varying per species:
1982:
1469:
1370:
1322:
1274:
1115:
1085:
971:
963:
958:
944:, once thought to be a pachycephalosaur, is now recognized as a specimen of the
850:
770:
712:
547:
527:
507:
487:
467:
436:
406:
45:
4551:
4524:
4517:
4239:
3936:
3717:
3548:
2862:
2845:
2576:
2553:
2539:
2483:
2358:
2146:
2142:
2040:
1910:
1809:
1785:
1394:
1180:
1090:
1053:
1049:
881:
853:
point to pachycephalosaurs having good vision, and uncharacteristically large
787:
782:. In 2017, a phylogenetic analysis conducted by Han and colleagues identified
741:
737:
720:
discovered. Often isolated skull fragments are the only bones that are found.
716:
696:
688:
457:
426:
416:
246:
122:
90:
55:
4714:
4216:
4034:
3944:
3679:
3556:
3433:
3323:
Dieudonné, P. -E.; Cruzado-Caballero, P.; Godefroit, P.; Tortosa, T. (2021).
3309:
3180:
3137:
2830:
2704:
2685:
Maryanska, T.; Chapman, R.E.; Weishampel, D.B. (2004). "Pachycephalosauria".
2471:, involved a migration from Asia to North America, most likely by way of the
1084:
and Thomas D. Carr discovered a clade of the Pachycephalosauridae that was a
3380:
2689:(2nd ed.). Berkeley: University of California Press. pp. 464–477.
2543:
2507:
2468:
2464:
2286:
2223:
2138:
1934:
948:
165:
95:
4177:
Fossil Record 3. New Mexico Museum of Natural History and Science, Bulletin
4147:"A taxonomic review of the Pachycephalosauridae (Dinosauria: Ornithischia)"
4120:
4087:
3915:
3628:
3399:
3273:
3081:"A taxonomic review of the Pachycephalosauridae (Dinosauria: Ornithischia)"
2940:
2871:
2765:
Han, F.-L.; Forster, C.A.; Clark, J.M.; Xu, X. (2016). "Cranial anatomy of
2743:
2315:
4708:
4319:
4310:
3992:(1974). "Pachycephalosauria, a new suborder of ornithischian dinosaurs".
3010:(1974). "Pachycephalosauria, a new suborder of ornithischian dinosaurs".
2472:
2455:
2202:, p. . This view was popularized in the 1956 science fiction story "
2159:
1755:
1045:
1013:
997:
684:
262:
198:
185:
85:
80:
65:
60:
50:
2730:
Evans, David; Brown, Caleb M.; You, Hailu; Campione, Nicolás E. (2021).
2306:
2278:
cannot be observed whether or not color played a role in dome function.
4004:(1986). "Phylogeny of the bird-hipped dinosaurs (Order Ornithischia)".
3264:
3239:
3114:"A new genus of derived pachycephalosaurian from western North America"
3060:(1986). "Phylogeny of the bird-hipped dinosaurs (Order Ornithischia)".
2529:
2150:
843:
751:
708:
100:
75:
3301:
2446:
and were carried by erosion after death to their final resting place.
4304:
4255:
4168:
Watabe, Mahito; Tsogtbaatar, Khishigjaw; Sullivan, Robert M. (2011).
2635:
175:
4685:
2267:
concluded, however, that the domes could withstand combat stresses.
970:). Further complicating matters are the diverse interpretations of
2418:
2387:
2242:
2170:
910:
877:
779:
765:
677:
340:
4743:
3817:(1970). "Pachycephalosaurids — dinosaurian battering rams".
1012:, the presence of fanglike premaxillary teeth, and the prominent
4252:
on shape-shifting dinosaur skulls and dinosaur misclassification
4689:
4297:
4259:
2289:, which had much more distinct cranial ornamentation. Longrich
628:
640:
120:
Montage of four pachycephalosaurs. Clockwise from top left:
4209:
10.1671/0272-4634(2002)022[0779:ANGODP]2.0.CO;2
3868:"Extreme Cranial Ontogeny in the Upper Cretaceous Dinosaur
3851:
10.1666/0094-8373(2004)030<0253:CHOPOM>2.0.CO;2
3514:
10.1666/0094-8373(2004)030<0253:CHOPOM>2.0.CO;2
3173:
10.1671/0272-4634(2002)022[0779:ANGODP]2.0.CO;2
3130:
10.1671/0272-4634(2002)022[0779:ANGODP]2.0.CO;2
2893:"Extreme Cranial Ontogeny in the Upper Cretaceous Dinosaur
723:
Candidates for the earliest-known pachycephalosaur include
661:
649:
646:
631:
622:
4042:
Snively, E; Theodor, JM (2011). Carpenter, Kenneth (ed.).
3238:
Evans DC, Schott RK, Larson DW, Brown CM, Ryan MJ (2013).
2234:
harm during flank-butting) and the squamosal horns of the
4154:
New Mexico Museum of Natural History and Science Bulletin
3088:
New Mexico Museum of Natural History and Science Bulletin
616:
610:
2374:
3112:
Williamson, Thomas E.; Carr, Thomas D. (2003-01-14).
664:
658:
655:
637:
625:
619:
613:
604:
3866:
Horner, JR; Goodwin, MB (2009). Sereno, Paul (ed.).
2883:
2881:
643:
607:
574:
564:
553:
543:
533:
523:
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503:
493:
483:
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3198:
3036:(3rd ed.). Blackwell Publishing. p. 472.
2281:
634:
3646:. San Diego, CA: Academic Press. pp. 329–339.
2808:
676:παχυκεφαλόσαυρος for 'thick headed lizards') is a
1033:
2145:, having different tooth morphology between the
1004:recovered the animals traditionally considered '
2506:. The second event occurred before the middle
2264:
4271:
4138:Neues Jahrbuch für Geologie und Paläontologie
3583:Peterson JE, Dischler C, Longrich NR (2013).
3578:
3576:
3574:
2598:
2596:
2594:
2592:
2475:. This migration was by a common ancestor of
2274:
2255:
8:
2716:
2714:
1024:The Pachycephalosauria was first named as a
3960:Longrich, NR; Sankey, J; Tanke, D (2010). "
4686:
4495:
4463:
4454:
4385:
4358:
4349:
4294:
4278:
4264:
4256:
3488:
3486:
3411:
3409:
2542:, have recently been shown to actually be
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111:
31:
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4067:
3905:
3895:
3618:
3608:
3389:
3379:
3263:
2930:
2920:
2861:
3325:"A new phylogeny of cerapodan dinosaurs"
2375:Peterson, Dischler & Longrich (2013)
967:
2660:"Genus List for Holtz (2007) Dinosaurs"
2588:
2454:Pachycephalosaurs lived exclusively in
2199:
3750:(3rd ed.). Blackwell Publishing.
2811:The Princeton field guide to dinosaurs
2268:
2211:
1057:
3830:Goodwin, MB; Horner, JR (June 2004).
2572:Timeline of pachycephalosaur research
7:
3662:Dinosaurs: a concise natural history
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2678:
2676:
2674:
2672:
2653:
2651:
2395:life restoration with cranial injury
2215:
876:, accompanied by the closing of the
3493:Goodwin MB, Horner JR (June 2004).
2605:Journal of Systematic Palaeontology
2282:Longrich, Sankey & Tanke (2010)
1998:
1974:
1950:
1926:
1902:
1825:
1801:
1777:
1770:
1762:
1584:
1532:
1520:
1461:
1451:
1427:
1386:
1362:
1338:
1314:
1290:
1266:
1256:
1172:
1165:
1155:
1131:
1121:
1036:. They included within it only one
4197:Journal of Vertebrate Paleontology
3925:Journal of Vertebrate Paleontology
3537:Journal of Vertebrate Paleontology
3161:Journal of Vertebrate Paleontology
3118:Journal of Vertebrate Paleontology
2771:Journal of Vertebrate Paleontology
2736:Canadian Journal of Earth Sciences
2254:A histological study conducted by
25:
4017:Snively, E; Cox, A (March 2008).
3698:Journal of the Geological Society
989:were just early growth stages of
4670:
4669:
4646:
4095:Stokstad, Erik (November 2007).
2556:
2334:
2325:
2314:
2305:
822:
802:
600:
152:
3416:Snively E, Cox A (March 2008).
1034:Maryańska & Osmólska (1974)
993:, rather than distinct genera.
860:Pachycephalosaurus wyomingensis
326:Pachycephalosaurus wyomingensis
4800:Taxa named by Halszka Osmólska
4795:Taxa named by Teresa Maryańska
3664:. Cambridge University Press.
2815:. Princeton University Press.
2658:Holtz, Thomas R. Jr. (2007) .
1:
4156:(35): 347–365. Archived from
4113:10.1126/science.318.5854.1236
3978:10.1016/j.cretres.2009.12.002
3341:10.1080/08912963.2020.1793979
3225:10.1016/j.cretres.2009.12.002
2968:10.1080/08912963.2020.1793979
2783:10.1080/02724634.2015.1029579
2617:10.1080/14772019.2024.2346577
703:, all of them being found in
4069:10.1371/journal.pone.0021422
4006:National Geographic Research
3897:10.1371/journal.pone.0007626
3807:Evolution of the Vertebrates
3610:10.1371/journal.pone.0068620
3207:Longrich, N.R.; Sankey, J.;
3062:National Geographic Research
2922:10.1371/journal.pone.0007626
2265:Snively & Theodor (2011)
2247:Restoration of head-butting
726:Ferganocephale adenticulatum
2275:Goodwin & Horner (2004)
2256:Goodwin & Horner (2004)
981:A 2009 paper proposed that
4816:
4785:Turonian first appearances
4023:Palaeontologia Electronica
3783:(1): 19–25. Archived from
3465:(1): 19–25. Archived from
3422:Palaeontologia Electronica
2981:Olshevsky, George (1991).
27:Extinct clade of dinosaurs
4790:Maastrichtian extinctions
4659:
4644:
4498:
4466:
4453:
4434:
4388:
4361:
4348:
4293:
4183:: 489–497. Archived from
3937:10.1080/02724631003763532
3718:10.1144/0016-76492007-154
3644:Encyclopedia of Dinosaurs
3549:10.1080/02724631003763532
3094:: 347–365. Archived from
2863:10.1016/j.cub.2016.07.066
2738:. e–First (10): 981–992.
2458:, being found in western
2054:
2037:
2020:
2003:
1996:
1979:
1972:
1955:
1948:
1931:
1924:
1907:
1900:
1883:
1847:
1830:
1823:
1806:
1799:
1782:
1775:
1768:
1604:
1589:
1582:
1567:
1552:
1537:
1530:
1518:
1483:
1466:
1459:
1449:
1432:
1425:
1408:
1391:
1384:
1367:
1360:
1343:
1336:
1319:
1312:
1295:
1288:
1271:
1264:
1254:
1228:
1211:
1194:
1177:
1170:
1163:
1153:
1136:
1129:
346:
339:
320:
313:
149:Scientific classification
147:
119:
110:
34:
3994:Palaeontologica Polonica
3777:Contributions to Geology
3748:Vertebrate Palaeontology
3459:Contributions to Geology
3034:Vertebrate Palaeontology
3012:Palaeontologica Polonica
2891:; Goodwin, M.B. (2009).
2261:Snively & Cox (2008)
1232:Stegoceras novomexicanum
1016:present in many genera.
707:and Asia. They were all
691:, it makes up the clade
3809:. New York: John Wiley.
3381:10.1186/1472-6785-13-14
3290:Papers in Palaeontology
2642:Oxford University Press
2429:in its paleoenvironment
842:Pachycephalosaurs were
365:Micropachycephalosaurus
334:, 1931 (conserved name)
2990:Earth Sciences Library
2744:10.1139/cjes-2020-0190
2430:
2396:
2251:
2194:
978:in pachycephalosaurs.
927:
878:supratemporal fenestra
4752:Paleobiology Database
4145:Sullivan, RM (2006).
3962:Texacephale langstoni
3244:Nature Communications
2638:UK English Dictionary
2422:
2391:
2246:
2174:
2167:Head-butting behavior
914:
4543:Pachycephalosaurinae
4491:Pachycephalosauridae
3658:Weishampel, David B.
3079:Sullivan RM (2006).
2631:"Pachycephalosauria"
2579:Convergent evolution
2535:Majungatholus atopus
2525:Yaverlandia bitholus
1261:Pachycephalosaurinae
1160:Pachycephalosauridae
1082:Thomas E. Williamson
996:A 2020 reworking of
923:as growth stages of
901:convergent evolution
829:Life restoration of
809:Life restoration of
743:Stenopelix valdensis
446:Pachycephalosaurinae
385:Pachycephalosauridae
18:Pachycephalosauridae
4060:2011PLoSO...621422S
3966:Cretaceous Research
3888:2009PLoSO...4.7626H
3710:2008JGSoc.165..613N
3601:2013PLoSO...868620P
3256:2013NatCo...4.1828E
3213:Cretaceous Research
2913:2009PLoSO...4.7626H
2636:Oxford Dictionaries
2297:Dome paleopathology
1766:Pachycephalosauria
1748:heterodontosauridae
1456:Pachycephalosaurini
1078:Dracorex hogwartsia
1048:, which unites the
786:as a member of the
771:Sinocephale bexelli
701:Northern Hemisphere
557:Pachycephalosaurini
4730:Pachycephalosauria
4700:Pachycephalosauria
4594:Pachycephalosaurus
4459:Pachycephalosauria
4438:Pachycephalosauria
4408:Pachycephalosauria
4287:Pachycephalosauria
3870:Pachycephalosaurus
3766:Carpenter, Kenneth
3329:Historical Biology
3265:10.1038/ncomms2749
3030:Benton, Michael J.
2956:Historical Biology
2895:Pachycephalosaurus
2503:Pachycephalosaurus
2473:Bering Land Bridge
2431:
2409:agonistic behavior
2397:
2393:Pachycephalosaurus
2365:Pachycephalosaurus
2252:
2249:Pachycephalosaurus
2208:L. Sprague de Camp
2204:A Gun for Dinosaur
2195:
2178:Pachycephalosaurus
2058:Pachycephalosaurus
1886:Heterodontosaurids
1487:Pachycephalosaurus
1215:Stegoceras validum
1126:Pachycephalosauria
1070:Pachycephalosaurus
1006:heterodontosaurids
991:Pachycephalosaurus
936:Pachycephalosauria
928:
925:Pachycephalosaurus
832:Pachycephalosaurus
815:(primitive member)
596:Pachycephalosauria
579:Pachycephalosaurus
295:Pachycephalosauria
135:Pachycephalosaurus
4780:Pachycephalosaurs
4767:
4766:
4692:Taxon identifiers
4683:
4682:
4655:
4654:
4642:
4641:
4638:
4637:
4449:
4448:
4445:
4444:
4430:
4429:
4426:
4425:
3757:978-0-632-05637-8
3744:Benton, Michael J
3335:(10): 2335–2355.
3302:10.1002/spp2.1535
3043:978-0-632-05637-8
2962:(10): 2335–2355.
2856:(19): 2674–2680.
2444:temperate climate
2285:ceratopsians and
2123:
2122:
2114:
2113:
2105:
2104:
2096:
2095:
2087:
2086:
2078:
2077:
2069:
2068:
1880:
1879:
1871:
1870:
1862:
1861:
1834:Heterodontosaurus
1743:
1742:
1734:
1733:
1725:
1724:
1716:
1715:
1707:
1706:
1698:
1697:
1689:
1688:
1680:
1679:
1671:
1670:
1662:
1661:
1653:
1652:
1644:
1643:
1635:
1634:
1626:
1625:
1617:
1616:
1507:
1506:
1498:
1497:
1243:
1242:
899:in an example of
835:(advanced member)
593:
592:
561:
450:
389:
309:
35:Pachycephalosaurs
16:(Redirected from
4807:
4760:
4759:
4747:
4746:
4734:
4733:
4732:
4719:
4718:
4717:
4687:
4673:
4672:
4650:
4496:
4464:
4455:
4386:
4359:
4350:
4343:
4342:
4295:
4280:
4273:
4266:
4257:
4242:
4228:
4191:
4189:
4174:
4164:
4162:
4151:
4141:
4132:
4091:
4081:
4071:
4038:
4013:
3997:
3981:
3956:
3919:
3909:
3899:
3862:
3836:
3826:
3810:
3798:
3796:
3795:
3789:
3774:
3761:
3730:
3729:
3690:
3684:
3683:
3654:
3648:
3647:
3639:
3633:
3632:
3622:
3612:
3580:
3569:
3568:
3532:
3526:
3525:
3499:
3490:
3481:
3480:
3478:
3477:
3471:
3456:
3444:
3438:
3437:
3413:
3404:
3403:
3393:
3383:
3359:
3353:
3352:
3320:
3314:
3313:
3284:
3278:
3277:
3267:
3235:
3229:
3228:
3204:
3193:
3192:
3156:
3150:
3149:
3109:
3103:
3102:
3100:
3085:
3076:
3070:
3069:
3054:
3048:
3047:
3026:
3020:
3019:
3000:
2994:
2993:
2987:
2978:
2972:
2971:
2951:
2945:
2944:
2934:
2924:
2885:
2876:
2875:
2865:
2841:
2835:
2834:
2814:
2805:Paul, Gregory S.
2801:
2795:
2794:
2762:
2756:
2755:
2727:
2721:
2718:
2709:
2708:
2682:
2667:
2666:
2664:
2655:
2646:
2645:
2627:
2621:
2620:
2600:
2566:
2564:Dinosaurs portal
2561:
2560:
2559:
2368:showing injuries
2338:
2329:
2318:
2309:
1999:
1975:
1951:
1927:
1903:
1826:
1802:
1778:
1771:
1763:
1607:S. edmontonensis
1585:
1533:
1521:
1462:
1452:
1428:
1387:
1363:
1339:
1315:
1291:
1267:
1257:
1173:
1166:
1156:
1132:
1122:
915:Diagram showing
826:
806:
762:Early Cretaceous
748:Early Cretaceous
671:
670:
667:
666:
663:
660:
657:
652:
651:
648:
645:
642:
639:
636:
633:
630:
627:
624:
621:
618:
615:
612:
609:
606:
576:
566:
559:
555:
545:
535:
525:
515:
505:
495:
485:
475:
465:
455:
448:
444:
434:
424:
414:
404:
394:
387:
383:
373:
362:
351:
323:
298:
293:
277:
261:
245:
229:
213:
157:
156:
115:
105:
42:
38:Temporal range:
32:
21:
4815:
4814:
4810:
4809:
4808:
4806:
4805:
4804:
4770:
4769:
4768:
4763:
4755:
4750:
4742:
4737:
4728:
4727:
4722:
4713:
4712:
4707:
4694:
4684:
4679:
4651:
4634:
4573:Foraminacephale
4537:
4485:
4441:
4422:
4402:
4375:
4369:Avemetatarsalia
4354:Avemetatarsalia
4344:
4338:Marginocephalia
4300:
4299:
4289:
4284:
4240:
4236:
4231:
4194:
4187:
4172:
4167:
4160:
4149:
4144:
4135:
4094:
4041:
4016:
4000:
3984:
3959:
3922:
3865:
3834:
3829:
3813:
3801:
3793:
3791:
3787:
3772:
3764:
3758:
3742:
3738:
3733:
3692:
3691:
3687:
3672:
3656:
3655:
3651:
3641:
3640:
3636:
3582:
3581:
3572:
3534:
3533:
3529:
3497:
3492:
3491:
3484:
3475:
3473:
3469:
3454:
3446:
3445:
3441:
3415:
3414:
3407:
3361:
3360:
3356:
3322:
3321:
3317:
3286:
3285:
3281:
3237:
3236:
3232:
3206:
3205:
3196:
3158:
3157:
3153:
3111:
3110:
3106:
3098:
3083:
3078:
3077:
3073:
3056:
3055:
3051:
3044:
3028:
3027:
3023:
3002:
3001:
2997:
2985:
2980:
2979:
2975:
2953:
2952:
2948:
2887:
2886:
2879:
2850:Current Biology
2843:
2842:
2838:
2823:
2803:
2802:
2798:
2777:(1): e1029579.
2764:
2763:
2759:
2729:
2728:
2724:
2719:
2712:
2697:
2684:
2683:
2670:
2662:
2657:
2656:
2649:
2629:
2628:
2624:
2602:
2601:
2590:
2586:
2562:
2557:
2555:
2552:
2452:
2440:Rocky Mountains
2423:Restoration of
2417:
2372:
2371:
2370:
2369:
2344:Skull domes of
2341:
2340:
2339:
2331:
2330:
2321:
2320:
2319:
2311:
2310:
2299:
2169:
2134:
2129:
2124:
2115:
2106:
2097:
2088:
2079:
2070:
1890:(paraphyletic)
1889:
1881:
1872:
1863:
1744:
1735:
1726:
1717:
1708:
1699:
1690:
1681:
1672:
1663:
1654:
1645:
1636:
1627:
1618:
1508:
1499:
1347:Foraminacephale
1244:
1100:
1022:
1010:cranial kinesis
976:sexual features
968:Sullivan (2006)
909:
855:olfactory lobes
840:
839:
838:
837:
836:
827:
818:
817:
816:
807:
796:
776:Late Cretaceous
757:Albalophosaurus
731:Middle Jurassic
693:Marginocephalia
654:
603:
599:
478:Foraminacephale
388:Sternberg, 1945
354:Albalophosaurus
335:
329:
303:
297:
291:
279:Marginocephalia
275:
259:
243:
227:
211:
151:
106:
104:
103:
98:
93:
88:
83:
78:
73:
68:
63:
58:
53:
48:
41:Late Cretaceous
40:
39:
36:
28:
23:
22:
15:
12:
11:
5:
4813:
4811:
4803:
4802:
4797:
4792:
4787:
4782:
4772:
4771:
4765:
4764:
4762:
4761:
4748:
4735:
4720:
4704:
4702:
4696:
4695:
4690:
4681:
4680:
4678:
4677:
4667:
4660:
4657:
4656:
4653:
4652:
4645:
4643:
4640:
4639:
4636:
4635:
4633:
4632:
4625:
4618:
4611:
4604:
4597:
4590:
4583:
4576:
4569:
4562:
4555:
4547:
4545:
4539:
4538:
4536:
4535:
4528:
4521:
4514:
4507:
4504:Colepiocephale
4499:
4493:
4487:
4486:
4484:
4483:
4476:
4472:Ferganocephale
4467:
4461:
4451:
4450:
4447:
4446:
4443:
4442:
4435:
4432:
4431:
4428:
4427:
4424:
4423:
4421:
4420:
4419:
4418:
4412:
4410:
4404:
4403:
4401:
4400:
4399:
4398:
4389:
4383:
4377:
4376:
4374:
4373:
4372:
4371:
4362:
4356:
4346:
4345:
4341:
4340:
4331:
4322:
4313:
4307:
4298:
4291:
4290:
4285:
4283:
4282:
4275:
4268:
4260:
4254:
4253:
4235:
4234:External links
4232:
4230:
4229:
4203:(4): 779–801.
4192:
4190:on 2011-09-29.
4165:
4163:on 2007-09-27.
4142:
4133:
4107:(5854): 1236.
4092:
4039:
4014:
3998:
3982:
3972:(2): 274–284.
3957:
3931:(3): 786–798.
3920:
3863:
3845:(2): 253–267.
3827:
3811:
3803:Colbert, Edwin
3799:
3762:
3756:
3739:
3737:
3734:
3732:
3731:
3704:(3): 613–623.
3685:
3670:
3649:
3634:
3570:
3543:(3): 786–798.
3527:
3508:(2): 253–267.
3482:
3439:
3405:
3354:
3315:
3279:
3230:
3219:(2): 274–284.
3194:
3167:(4): 779–801.
3151:
3124:(4): 779–801.
3104:
3101:on 2007-09-27.
3071:
3049:
3042:
3021:
2995:
2973:
2946:
2877:
2836:
2821:
2796:
2767:Yinlong downsi
2757:
2722:
2720:Sullivan 2006
2710:
2696:978-0520242098
2695:
2687:The Dinosauria
2668:
2647:
2622:
2611:(1). 2346577.
2587:
2585:
2582:
2581:
2580:
2574:
2568:
2567:
2551:
2548:
2451:
2448:
2416:
2413:
2343:
2342:
2333:
2332:
2324:
2323:
2322:
2313:
2312:
2304:
2303:
2302:
2301:
2300:
2298:
2295:
2200:Colbert (1955)
2168:
2165:
2133:
2130:
2128:
2125:
2121:
2120:
2117:
2116:
2112:
2111:
2108:
2107:
2103:
2102:
2099:
2098:
2094:
2093:
2090:
2089:
2085:
2084:
2081:
2080:
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2072:
2071:
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2066:
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2062:
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2050:
2049:
2046:
2045:
2036:
2033:
2032:
2029:
2028:
2019:
2016:
2015:
2012:
2011:
2002:
1997:
1995:
1992:
1991:
1988:
1987:
1978:
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1971:
1968:
1967:
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1963:
1954:
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1947:
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1732:
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1728:
1727:
1723:
1722:
1719:
1718:
1714:
1713:
1710:
1709:
1705:
1704:
1701:
1700:
1696:
1695:
1692:
1691:
1687:
1686:
1683:
1682:
1678:
1677:
1674:
1673:
1669:
1668:
1665:
1664:
1660:
1659:
1656:
1655:
1651:
1650:
1647:
1646:
1642:
1641:
1638:
1637:
1633:
1632:
1629:
1628:
1624:
1623:
1620:
1619:
1615:
1614:
1611:
1610:
1603:
1600:
1599:
1596:
1595:
1592:S. buchholtzae
1588:
1583:
1581:
1578:
1577:
1574:
1573:
1566:
1563:
1562:
1559:
1558:
1551:
1548:
1547:
1544:
1543:
1536:
1531:
1529:
1519:
1517:
1514:
1513:
1510:
1509:
1505:
1504:
1501:
1500:
1496:
1495:
1492:
1491:
1482:
1479:
1478:
1475:
1474:
1465:
1460:
1458:
1450:
1448:
1445:
1444:
1441:
1440:
1431:
1426:
1424:
1421:
1420:
1417:
1416:
1407:
1404:
1403:
1400:
1399:
1390:
1385:
1383:
1380:
1379:
1376:
1375:
1366:
1361:
1359:
1356:
1355:
1352:
1351:
1342:
1337:
1335:
1332:
1331:
1328:
1327:
1318:
1313:
1311:
1308:
1307:
1304:
1303:
1294:
1289:
1287:
1284:
1283:
1280:
1279:
1270:
1265:
1263:
1255:
1253:
1250:
1249:
1246:
1245:
1241:
1240:
1237:
1236:
1227:
1224:
1223:
1220:
1219:
1210:
1207:
1206:
1203:
1202:
1198:Colepiocephale
1193:
1190:
1189:
1186:
1185:
1176:
1171:
1169:
1164:
1162:
1154:
1152:
1149:
1148:
1145:
1144:
1135:
1130:
1128:
1120:
1099:
1096:
1044:of a suborder
1021:
1018:
908:
907:Classification
905:
847:ornithischians
828:
821:
820:
819:
808:
801:
800:
799:
798:
797:
795:
792:
591:
590:
589:
588:
587:
586:
585:
584:
583:
582:
572:
560:Sullivan, 2003
551:
541:
531:
521:
511:
501:
491:
481:
471:
461:
440:
430:
420:
410:
400:
397:Colepiocephale
379:
369:
358:
344:
343:
337:
336:
330:
318:
317:
311:
310:
306:conserved name
289:
282:
281:
273:
266:
265:
257:
250:
249:
241:
234:
233:
231:Neornithischia
225:
218:
217:
209:
202:
201:
196:
189:
188:
183:
179:
178:
173:
169:
168:
163:
159:
158:
145:
144:
117:
116:
108:
107:
99:
94:
89:
84:
79:
74:
69:
64:
59:
54:
49:
44:
43:
37:
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
4812:
4801:
4798:
4796:
4793:
4791:
4788:
4786:
4783:
4781:
4778:
4777:
4775:
4758:
4753:
4749:
4745:
4740:
4736:
4731:
4725:
4721:
4716:
4710:
4706:
4705:
4703:
4701:
4697:
4693:
4688:
4676:
4668:
4666:
4662:
4661:
4658:
4649:
4631:
4630:
4626:
4624:
4623:
4622:Sphaerotholus
4619:
4617:
4616:
4612:
4610:
4609:
4605:
4603:
4602:
4598:
4596:
4595:
4591:
4589:
4588:
4587:Homalocephale
4584:
4582:
4581:
4577:
4575:
4574:
4570:
4568:
4567:
4563:
4561:
4560:
4559:Alaskacephale
4556:
4554:
4553:
4549:
4548:
4546:
4544:
4540:
4534:
4533:
4529:
4527:
4526:
4522:
4520:
4519:
4515:
4513:
4512:
4508:
4506:
4505:
4501:
4500:
4497:
4494:
4492:
4488:
4482:
4481:
4480:Wannanosaurus
4477:
4474:
4473:
4469:
4468:
4465:
4462:
4460:
4456:
4452:
4440:
4439:
4433:
4416:
4415:
4414:
4413:
4411:
4409:
4405:
4397:
4393:
4392:
4391:
4390:
4387:
4384:
4382:
4378:
4370:
4366:
4365:
4364:
4363:
4360:
4357:
4355:
4351:
4347:
4339:
4335:
4332:
4330:
4326:
4323:
4321:
4317:
4314:
4312:
4308:
4306:
4302:
4301:
4296:
4292:
4288:
4281:
4276:
4274:
4269:
4267:
4262:
4261:
4258:
4251:
4247:
4243:
4238:
4237:
4233:
4226:
4222:
4218:
4214:
4210:
4206:
4202:
4198:
4193:
4186:
4182:
4178:
4171:
4166:
4159:
4155:
4148:
4143:
4139:
4134:
4130:
4126:
4122:
4118:
4114:
4110:
4106:
4102:
4098:
4093:
4089:
4085:
4080:
4075:
4070:
4065:
4061:
4057:
4054:(6): e21422.
4053:
4049:
4045:
4040:
4036:
4032:
4028:
4024:
4020:
4015:
4011:
4007:
4003:
3999:
3996:(30): 45–102.
3995:
3991:
3987:
3983:
3979:
3975:
3971:
3967:
3963:
3958:
3954:
3950:
3946:
3942:
3938:
3934:
3930:
3926:
3921:
3917:
3913:
3908:
3903:
3898:
3893:
3889:
3885:
3882:(10): e7626.
3881:
3877:
3873:
3871:
3864:
3860:
3856:
3852:
3848:
3844:
3840:
3833:
3828:
3824:
3820:
3816:
3812:
3808:
3804:
3800:
3790:on 2016-03-03
3786:
3782:
3778:
3771:
3767:
3763:
3759:
3753:
3749:
3745:
3741:
3740:
3735:
3727:
3723:
3719:
3715:
3711:
3707:
3703:
3699:
3695:
3689:
3686:
3681:
3677:
3673:
3671:9780511479410
3667:
3663:
3659:
3653:
3650:
3645:
3638:
3635:
3630:
3626:
3621:
3616:
3611:
3606:
3602:
3598:
3595:(7): e68620.
3594:
3590:
3586:
3579:
3577:
3575:
3571:
3566:
3562:
3558:
3554:
3550:
3546:
3542:
3538:
3531:
3528:
3523:
3519:
3515:
3511:
3507:
3503:
3496:
3489:
3487:
3483:
3472:on 2016-03-03
3468:
3464:
3460:
3453:
3449:
3448:Carpenter, K.
3443:
3440:
3435:
3431:
3427:
3423:
3419:
3412:
3410:
3406:
3401:
3397:
3392:
3387:
3382:
3377:
3373:
3369:
3365:
3358:
3355:
3350:
3346:
3342:
3338:
3334:
3330:
3326:
3319:
3316:
3311:
3307:
3303:
3299:
3295:
3291:
3283:
3280:
3275:
3271:
3266:
3261:
3257:
3253:
3249:
3245:
3241:
3234:
3231:
3226:
3222:
3218:
3214:
3210:
3203:
3201:
3199:
3195:
3190:
3186:
3182:
3178:
3174:
3170:
3166:
3162:
3155:
3152:
3147:
3143:
3139:
3135:
3131:
3127:
3123:
3119:
3115:
3108:
3105:
3097:
3093:
3089:
3082:
3075:
3072:
3067:
3063:
3059:
3053:
3050:
3045:
3039:
3035:
3031:
3025:
3022:
3017:
3013:
3009:
3005:
2999:
2996:
2991:
2984:
2977:
2974:
2969:
2965:
2961:
2957:
2950:
2947:
2942:
2938:
2933:
2928:
2923:
2918:
2914:
2910:
2907:(10): e7626.
2906:
2902:
2898:
2896:
2890:
2884:
2882:
2878:
2873:
2869:
2864:
2859:
2855:
2851:
2847:
2840:
2837:
2832:
2828:
2824:
2822:9780691137209
2818:
2813:
2812:
2806:
2800:
2797:
2792:
2788:
2784:
2780:
2776:
2772:
2768:
2761:
2758:
2753:
2749:
2745:
2741:
2737:
2733:
2726:
2723:
2717:
2715:
2711:
2706:
2702:
2698:
2692:
2688:
2681:
2679:
2677:
2675:
2673:
2669:
2661:
2654:
2652:
2648:
2643:
2639:
2637:
2632:
2626:
2623:
2618:
2614:
2610:
2606:
2599:
2597:
2595:
2593:
2589:
2583:
2578:
2575:
2573:
2570:
2569:
2565:
2554:
2549:
2547:
2545:
2541:
2537:
2536:
2531:
2527:
2526:
2521:
2520:
2515:
2514:
2509:
2505:
2504:
2499:
2497:
2492:
2491:
2486:
2485:
2480:
2479:
2474:
2470:
2466:
2461:
2460:North America
2457:
2449:
2447:
2445:
2441:
2437:
2428:
2427:
2426:Homalocephale
2421:
2414:
2412:
2410:
2406:
2402:
2394:
2390:
2386:
2384:
2380:
2379:osteomyelitis
2376:
2367:
2366:
2361:
2360:
2355:
2354:
2353:Sphaerotholus
2349:
2348:
2337:
2328:
2317:
2308:
2296:
2294:
2292:
2288:
2283:
2279:
2276:
2272:
2270:
2269:Lehman (2010)
2266:
2262:
2257:
2250:
2245:
2241:
2239:
2238:
2231:
2227:
2225:
2221:
2220:bighorn sheep
2217:
2213:
2212:Galton (1970)
2209:
2205:
2201:
2192:
2191:
2186:
2185:
2180:
2179:
2173:
2166:
2164:
2161:
2157:
2152:
2148:
2144:
2140:
2131:
2126:
2119:
2118:
2110:
2109:
2101:
2100:
2092:
2091:
2083:
2082:
2074:
2073:
2065:
2064:
2061:
2060:
2059:
2052:
2051:
2048:
2047:
2044:
2043:
2042:
2035:
2034:
2031:
2030:
2027:
2026:
2025:
2024:Homalocephale
2018:
2017:
2014:
2013:
2010:
2009:
2008:
2001:
2000:
1994:
1993:
1990:
1989:
1986:
1985:
1984:
1977:
1976:
1970:
1969:
1966:
1965:
1962:
1961:
1960:
1959:Wannanosaurus
1953:
1952:
1946:
1945:
1942:
1941:
1938:
1937:
1936:
1929:
1928:
1922:
1921:
1918:
1917:
1914:
1913:
1912:
1905:
1904:
1898:
1897:
1894:
1893:
1887:
1876:
1875:
1867:
1866:
1858:
1857:
1854:
1853:
1852:
1851:Abrictosaurus
1845:
1844:
1841:
1840:
1837:
1836:
1835:
1828:
1827:
1821:
1820:
1817:
1816:
1813:
1812:
1811:
1804:
1803:
1797:
1796:
1793:
1792:
1789:
1788:
1787:
1780:
1779:
1773:
1772:
1765:
1764:
1760:
1757:
1753:
1749:
1739:
1738:
1730:
1729:
1721:
1720:
1712:
1711:
1703:
1702:
1694:
1693:
1685:
1684:
1676:
1675:
1667:
1666:
1658:
1657:
1649:
1648:
1640:
1639:
1631:
1630:
1622:
1621:
1613:
1612:
1609:
1608:
1602:
1601:
1598:
1597:
1594:
1593:
1587:
1586:
1580:
1579:
1576:
1575:
1572:
1571:
1565:
1564:
1561:
1560:
1557:
1556:
1550:
1549:
1546:
1545:
1542:
1541:
1535:
1534:
1528:
1527:
1526:Sphaerotholus
1523:
1522:
1516:
1515:
1512:
1511:
1503:
1502:
1494:
1493:
1490:
1489:
1488:
1481:
1480:
1477:
1476:
1473:
1472:
1471:
1464:
1463:
1457:
1454:
1453:
1447:
1446:
1443:
1442:
1439:
1438:
1437:
1436:Alaskacephale
1430:
1429:
1423:
1422:
1419:
1418:
1415:
1414:
1413:
1406:
1405:
1402:
1401:
1398:
1397:
1396:
1389:
1388:
1382:
1381:
1378:
1377:
1374:
1373:
1372:
1365:
1364:
1358:
1357:
1354:
1353:
1350:
1349:
1348:
1341:
1340:
1334:
1333:
1330:
1329:
1326:
1325:
1324:
1317:
1316:
1310:
1309:
1306:
1305:
1302:
1301:
1300:
1299:Homalocephale
1293:
1292:
1286:
1285:
1282:
1281:
1278:
1277:
1276:
1269:
1268:
1262:
1259:
1258:
1252:
1251:
1248:
1247:
1239:
1238:
1235:
1234:
1233:
1226:
1225:
1222:
1221:
1218:
1217:
1216:
1209:
1208:
1205:
1204:
1201:
1200:
1199:
1192:
1191:
1188:
1187:
1184:
1183:
1182:
1175:
1174:
1168:
1167:
1161:
1158:
1157:
1151:
1150:
1147:
1146:
1143:
1142:
1141:
1140:Wannanosaurus
1134:
1133:
1127:
1124:
1123:
1119:
1117:
1113:
1109:
1108:Homalocephale
1105:
1097:
1095:
1093:
1092:
1088:to the genus
1087:
1083:
1079:
1073:
1071:
1067:
1063:
1059:
1058:Sereno (1986)
1055:
1051:
1047:
1043:
1039:
1035:
1031:
1028:of the order
1027:
1019:
1017:
1015:
1011:
1007:
1003:
1000:by Dieudonné
999:
994:
992:
988:
984:
979:
977:
973:
969:
965:
961:
960:
955:
954:
953:Majungasaurus
950:
947:
943:
942:
941:Majungatholus
937:
933:
926:
922:
918:
913:
906:
904:
902:
898:
897:Protopyknosia
893:
891:
887:
883:
879:
875:
871:
867:
863:
861:
856:
852:
848:
845:
834:
833:
825:
814:
813:
812:Wannanosaurus
805:
793:
791:
789:
785:
781:
777:
773:
772:
767:
763:
759:
758:
753:
749:
745:
744:
739:
735:
732:
728:
727:
721:
718:
714:
710:
706:
705:North America
702:
698:
694:
690:
687:. Along with
686:
683:
682:ornithischian
679:
675:
669:
597:
581:
580:
573:
571:
570:
569:Alaskacephale
563:
562:
558:
552:
550:
549:
542:
540:
539:
538:Sphaerotholus
532:
530:
529:
522:
520:
519:
512:
510:
509:
502:
500:
499:
498:Homalocephale
492:
490:
489:
482:
480:
479:
472:
470:
469:
462:
460:
459:
452:
451:
447:
441:
439:
438:
431:
429:
428:
421:
419:
418:
411:
409:
408:
401:
399:
398:
391:
390:
386:
380:
378:
377:
376:Wannanosaurus
370:
367:
366:
359:
356:
355:
348:
347:
345:
342:
338:
333:
328:
327:
319:
316:
312:
307:
301:
296:
290:
287:
284:
283:
280:
274:
271:
268:
267:
264:
258:
255:
252:
251:
248:
242:
239:
236:
235:
232:
226:
223:
220:
219:
216:
210:
207:
204:
203:
200:
197:
194:
191:
190:
187:
184:
181:
180:
177:
174:
171:
170:
167:
164:
161:
160:
155:
150:
146:
143:
142:
141:Homalocephale
137:
136:
131:
130:
125:
124:
118:
114:
109:
102:
97:
92:
87:
82:
77:
72:
67:
62:
57:
52:
47:
33:
30:
19:
4699:
4627:
4620:
4613:
4608:Prenocephale
4606:
4599:
4592:
4585:
4578:
4571:
4564:
4557:
4550:
4530:
4523:
4516:
4509:
4502:
4478:
4470:
4458:
4437:
4436:
4407:
4396:Ornithischia
4381:Ornithischia
4333:
4329:Ornithischia
4324:
4315:
4286:
4200:
4196:
4185:the original
4180:
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4158:the original
4153:
4137:
4104:
4100:
4051:
4047:
4026:
4022:
4009:
4005:
3993:
3986:Maryańska, T
3969:
3965:
3961:
3928:
3924:
3879:
3875:
3869:
3842:
3839:Paleobiology
3838:
3822:
3818:
3806:
3792:. Retrieved
3785:the original
3780:
3776:
3747:
3701:
3697:
3688:
3661:
3652:
3643:
3637:
3592:
3588:
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3530:
3505:
3502:Paleobiology
3501:
3474:. Retrieved
3467:the original
3462:
3458:
3442:
3425:
3421:
3371:
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3357:
3332:
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3296:(6). e1535.
3293:
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3282:
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3164:
3160:
3154:
3121:
3117:
3107:
3096:the original
3091:
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3065:
3061:
3058:Sereno, P.C.
3052:
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3015:
3011:
2998:
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2959:
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2949:
2904:
2900:
2894:
2889:Horner, J.R.
2853:
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2774:
2770:
2766:
2760:
2735:
2725:
2686:
2634:
2625:
2608:
2604:
2533:
2523:
2517:
2513:Prenocephale
2511:
2501:
2496:Prenocephale
2494:
2488:
2482:
2476:
2453:
2450:Distribution
2436:arid climate
2432:
2424:
2415:Paleoecology
2404:
2398:
2392:
2373:
2363:
2357:
2351:
2345:
2290:
2287:hadrosaurids
2280:
2273:
2253:
2248:
2235:
2232:
2228:
2196:
2188:
2184:Prenocephale
2182:
2176:
2147:premaxillary
2135:
2127:Paleobiology
2056:
2055:
2039:
2038:
2022:
2021:
2007:Prenocephale
2005:
2004:
1981:
1980:
1957:
1956:
1933:
1932:
1909:
1908:
1849:
1848:
1832:
1831:
1808:
1807:
1784:
1783:
1752:paraphyletic
1745:
1606:
1605:
1591:
1590:
1570:S. triregnum
1569:
1568:
1554:
1553:
1539:
1538:
1524:
1485:
1484:
1468:
1467:
1455:
1434:
1433:
1412:Prenocephale
1410:
1409:
1393:
1392:
1369:
1368:
1345:
1344:
1321:
1320:
1297:
1296:
1273:
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1196:
1195:
1179:
1178:
1159:
1138:
1137:
1125:
1111:
1107:
1103:
1101:
1089:
1077:
1074:
1069:
1065:
1062:phylogenetic
1050:ceratopsians
1030:Ornithischia
1023:
1001:
995:
990:
986:
982:
980:
957:
951:
939:
935:
929:
924:
920:
916:
894:
890:postorbitals
858:
841:
830:
810:
783:
769:
755:
742:
725:
722:
595:
594:
577:
567:
556:
546:
536:
526:
518:Prenocephale
516:
506:
496:
486:
476:
466:
456:
449:Sereno, 1997
445:
435:
425:
415:
405:
395:
384:
374:
363:
352:
324:
315:Type species
294:
285:
269:
253:
237:
221:
215:Ornithischia
205:
192:
139:
133:
129:Prenocephale
127:
121:
29:
4724:Wikispecies
4629:Tylocephale
4615:Sinocephale
4601:Platytholus
4580:Goyocephale
4566:Amtocephale
4532:Texacephale
4511:Gravitholus
4250:Jack Horner
3990:Osmólska, H
3368:BMC Ecology
3004:Maryańska T
2519:Tylocephale
2490:Tylocephale
2478:Stygimoloch
2401:fibroblasts
2347:Gravitholus
2237:Stygimoloch
2216:Sues (1978)
2190:Stygimoloch
2143:heterodonty
1983:Goyocephale
1540:S. goodwini
1470:Stygimoloch
1371:Amtocephale
1323:Tylocephale
1275:Goyocephale
1116:Paul Sereno
1112:Goyocephale
1086:sister taxa
1054:ornithopods
987:Stygimoloch
972:ontogenetic
964:coelurosaur
959:Yaverlandia
946:abelisaurid
921:Stygimoloch
851:optic nerve
794:Description
713:herbivorous
548:Tylocephale
528:Sinocephale
508:Platytholus
488:Goyocephale
468:Amtocephale
437:Texacephale
407:Gravitholus
4774:Categories
4663:See also:
4552:Acrotholus
4525:Stegoceras
4518:Hanssuesia
4417:see below↓
4320:Dinosauria
4140:: 459–472.
4012:: 234–256.
4002:Sereno, PC
3794:2011-07-16
3736:References
3476:2011-07-16
3068:: 234–256.
3008:Osmólska H
2577:Triopticus
2540:Madagascar
2484:Stegoceras
2359:Stegoceras
2149:teeth and
2041:Stegoceras
1911:Tianyulong
1810:Lycorhinus
1786:Fruitadens
1395:Acrotholus
1181:Hanssuesia
1104:Stegoceras
1091:Stegoceras
1066:Stegoceras
1042:infraorder
966:(Naish in
886:squamosals
866:thickening
788:Ceratopsia
784:Stenopelix
764:strata of
750:strata of
738:Kyrgyzstan
736:strata of
717:omnivorous
697:Cretaceous
689:Ceratopsia
458:Acrotholus
427:Stegoceras
417:Hanssuesia
247:Pyrodontia
199:Dinosauria
123:Stegoceras
4303:Kingdom:
4241:TEDx talk
4217:0272-4634
4035:1094-8074
3953:129592428
3945:0272-4634
3819:Discovery
3815:Galton, P
3726:129624992
3694:Naish, D.
3680:476234422
3565:129592428
3557:0272-4634
3434:1094-8074
3349:221854017
3310:2056-2799
3209:Tanke, D.
3181:0272-4634
3138:0272-4634
3018:: 45–102.
2831:930852339
2791:130791053
2752:244227050
2705:493366196
2544:theropods
2508:Campanian
2469:Campanian
2467:or early
2465:Santonian
2224:musk oxen
2156:denticles
2151:maxillary
2139:Laramidia
1935:Echinodon
1555:S. lyonsi
1098:Phylogeny
1060:, in his
932:taxonomic
874:parietals
774:from the
760:from the
685:dinosaurs
300:Sternberg
172:Kingdom:
166:Eukaryota
4744:42418466
4709:Wikidata
4675:Category
4665:Timeline
4311:Chordata
4309:Phylum:
4305:Animalia
4225:86112901
4129:36443204
4121:18033861
4088:21738658
4048:PLOS ONE
3916:19859556
3876:PLOS ONE
3859:84961066
3825:: 23–32.
3805:(1955).
3768:(1997).
3746:(2004).
3660:(2009).
3629:23874691
3589:PLOS ONE
3522:84961066
3450:(1997).
3400:23557203
3274:23652016
3250:. 1828.
3189:86112901
3146:86112901
3032:(2004).
2941:19859556
2901:PLOS ONE
2872:27666971
2807:(2010).
2550:See also
2456:Laurasia
1756:Jurassic
1046:Cerapoda
1026:suborder
1020:Taxonomy
1014:diastema
998:Cerapoda
983:Dracorex
949:theropod
917:Dracorex
870:frontals
263:Cerapoda
186:Chordata
182:Phylum:
176:Animalia
162:Domain:
4715:Q131376
4246:YouTube
4101:Science
4079:3125168
4056:Bibcode
3907:2762616
3884:Bibcode
3706:Bibcode
3620:3712952
3597:Bibcode
3391:3637170
3252:Bibcode
2932:2762616
2909:Bibcode
2530:England
2160:dentary
2132:Feeding
868:of the
844:bipedal
752:Germany
709:bipedal
672:; from
332:Gilmore
4757:147917
4223:
4215:
4127:
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3904:
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3754:
3724:
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3668:
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3563:
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3432:
3398:
3388:
3374:: 14.
3347:
3308:
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3179:
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2992:: 104.
2939:
2929:
2870:
2829:
2819:
2789:
2750:
2703:
2693:
2405:et al.
2383:family
2362:, and
2291:et al.
1750:to be
1038:family
1002:et al.
956:, and
888:, and
882:jugals
734:Period
341:Genera
302:, 1945
4334:Clade
4325:Clade
4316:Clade
4221:S2CID
4188:(PDF)
4173:(PDF)
4161:(PDF)
4150:(PDF)
4125:S2CID
4029:(1).
3949:S2CID
3855:S2CID
3835:(PDF)
3788:(PDF)
3773:(PDF)
3722:S2CID
3561:S2CID
3518:S2CID
3498:(PDF)
3470:(PDF)
3455:(PDF)
3428:(1).
3345:S2CID
3185:S2CID
3142:S2CID
3099:(PDF)
3084:(PDF)
2986:(PDF)
2787:S2CID
2748:S2CID
2663:(PDF)
2584:Notes
2206:" by
2187:(B),
2181:(A),
780:China
766:Japan
746:from
729:from
678:clade
674:Greek
286:Clade
270:Clade
254:Clade
238:Clade
222:Clade
206:Clade
193:Clade
4394:see
4367:see
4213:ISSN
4117:PMID
4084:PMID
4031:ISSN
3941:ISSN
3912:PMID
3752:ISBN
3676:OCLC
3666:ISBN
3625:PMID
3553:ISSN
3430:ISSN
3396:PMID
3306:ISSN
3270:PMID
3177:ISSN
3134:ISSN
3038:ISBN
2937:PMID
2868:PMID
2827:OCLC
2817:ISBN
2701:OCLC
2691:ISBN
2532:and
2516:and
2500:and
2434:and
2263:and
2222:and
2214:and
1110:and
1068:and
1052:and
985:and
974:and
919:and
872:and
740:and
138:and
46:PreꞒ
4739:EoL
4248:by
4244:on
4205:doi
4109:doi
4105:318
4074:PMC
4064:doi
3974:doi
3933:doi
3902:PMC
3892:doi
3847:doi
3714:doi
3702:165
3615:PMC
3605:doi
3545:doi
3510:doi
3386:PMC
3376:doi
3337:doi
3298:doi
3260:doi
3221:doi
3169:doi
3126:doi
2964:doi
2927:PMC
2917:doi
2858:doi
2779:doi
2740:doi
2613:doi
2538:of
2528:of
2193:(C)
1032:by
778:of
680:of
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