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Palaeovertebrata in press article


Difficulties with the origin of dinosaurs: a comment on the current debate
Matthew G. Baron
Keywords: dinosaur anatomy; dinosaur evolution; Ornithoscelida; palaeobiogeography; Triassic Period

doi: 10.18563/pv.43.1.e3
 

Cite this article: Baron M. G., 2020. Difficulties with the origin of dinosaurs: a comment on the current debate. Palaeovertebrata 43 (1)-e3 . doi: 10.18563/pv.43.1.e3

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Abstract

The origin and early evolutionary history of the dinosaurs is a topic that has recently gone through a period of renewed interest and academic debate. For 130 years, one way of classifying the various dinosaur subgroups persisted as the accepted model, with increasing levels of research in the past quarter-century also providing evidence for the hypothesis that dinosaur origination occurred in the Southern Hemisphere, particularly in South America. It is, after all, from within the Late Triassic strata of countries like Argentina and Brazil that we get some of the very best early dinosaur specimens; many of these specimens are the earliest known representatives of some of the major dinosaur subgroups, such as the theropods and sauropodomorphs. However, some recent analyses have brought about a shift in terms of what is currently accepted and what is now disputed regarding the origin of dinosaurs – the Southern Hemisphere origination hypothesis was questioned (although this was based upon observations and not with quantitative analysis techniques), as has the shape of the dinosaur tree. Responses to the new hypothesis were numerous; many further supported a Southern Hemisphere point of origin. Whilst the interrelationships between the major dinosaur clades remains to be resolved, the current data does seem to comprehensively answer the question of where the dinosaurs first originated. However, it is arguable whether the current data that is being used in such palaeobiogeographical analyses is sufficient to provide an answer to the question of where specifically the dinosaur clade first appeared. This short communication urges a degree of caution about the current consensus and what steps may need to be taken to ensure that more meaningful results are produced in the future. 



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Bibliography

Agnolín, F. L., Rozadilla, S. 2017. Phylogenetic reassessment of Pisanosaurus mertii Casamiquela, 1967, a basal dinosauriform from the Late Triassic of Argentina. Journal of Systematic Palaeontology 16 (10):853-879. https://doi.org/10.1080/14772019.2017.1352623
 
Baron, M. G., Barrett, P. M. 2017. A dinosaur missing-link? Chilesaurus and the early evolution of ornithischian dinosaurs. Biology Letters 13 (8): 20170220. https://doi.org/10.1098/rsbl.2017.0220
 
Baron, M. G., Williams, M. E. 2018. A re-evaluation of the enigmatic dinosauriform Caseosaurus crosbyensis from the Late Triassic of Texas, USA and its implications for early dinosaur evolution. Acta Palaeontologica Polonica 63 (1): 129-145. https://doi.org/10.4202/app.00372.2017
 
Baron, M. G., Norman, D. B., Barrett, P. M. 2017a. A new hypothesis of dinosaur relationships and early dinosaur evolution. Nature 543, 501-506. https://doi.org/10.1038/nature21700
 
Baron, M. G., Norman, D. B., Barrett, P. M. 2017b. Untangling the dinosaur family tree: a rebuttal. Nature 551:E4-E5. https://doi.org/10.1038/nature24012
 
Barret, P. M., Butler, R. J., Edwards, N. P., Milner, A. R. 2008. Pterosaur distribution in time and space: an atlas. Flugsaurier: Pterosaur papers in honour of Peter Wellnhofer. 2008. Hone, D. W. E., and Buffetaut, E. (eds). Zitteliana B, 28. p.61-107.
 
Brusatte, S. L. 2017. Evolution: Uprooting the Dinosaur Family Tree. Current Biology 27(10): R390-R392. https://doi.org/10.1016/j.cub.2017.04.001
 
Brusatte, S. L, Nesbitt, S. J., Irmis, R. B., Butler, R. J., Benton, M. J., Norell, M. A. 2010a. The origin and early radiation of dinosaurs. Earth-Science Reviews 101(1):68-100. https://doi.org/10.1016/j.earscirev.2010.04.001
 
Brusatte, S. L., Niedźwiedzki, G., Butler, R. J. 2010b. Footprints pull origin and diversification of dinosaur stem lineage deep into Early Triassic. Proceedings of the Royal Society B. 278 (1708): 1107-1113. https://doi.org/10.1098/rspb.2010.1746
 
Cabreira, S. F, Kellner, A. W. A., Dias-da-Silva, S., da Silva, L. R, Bronzati, M., Marsola, J. C. A., Müller, R. T., de Souza Bittencourt, J., Batista, B. J., Raugust, T., Carrilho, R., Brodt, A., Langer, M. C. 2016. A unique Late Triassic dinosauromorph assemblage reveals dinosaur ancestral anatomy and diet. Current Biology 26 (22): 3090-3095. https://doi.org/10.1016/j.cub.2016.09.040
 
Dzik, J. 2003. A beaked herbivorous archosaur with dinosaur affinities from the early Late Triassic of Poland. Journal of Vertebrate Paleontology 23 (3): 556-574. https://doi.org/10.1671/A1097
 
Ferigolo, J., Langer, M. C. 2006. A Late Triassic dinosauriform from south Brazil and the origin of the ornithischian predentary bone. Historical Biology 19 (1): 1-11. https://doi.org/10.1080/08912960600845767
 
Langer, M. C., Benton, M. J. 2006. Early dinosaurs: a phylogenetic study. Journal of Systematic Palaeontology 4:309-358. https://doi.org/10.1017/S1477201906001970
 
Langer, M. C., Ezcurra, M. D., Rauhut, O. W. M., Benton, M. J., Knoll, F., McPhee, B. W., Novas, F. E., Pol, D., Brusatte, S. L. 2017. Untangling the dinosaur family tree. Nature 551 (7678): E1-E3. https://doi.org/10.1038/nature24011
 
Lee, M. S. Y., Baron, M. G., Norman, D. B., Barrett, P. M. 2019. Dynamic biogeographic models and dinosaur origins. Earth and Environmental Science Transactions of the Royal Society of Edinburgh 109 (1-2): 325-332. https://doi.org/10.1017/S1755691018000920
 
Marsola, J. C. A., Ferreira, G. S., Langer, M. C., Button, D. J., Butler, R. J. 2019. Increases in sampling support the southern Gondwanan hypothesis for the origin of dinosaurs. Palaeontology 62: 473-482. https://doi.org/10.1111/pala.12411
 
Martinez, R. N., Sereno, P. C., Alcober, O. A., Colombi, C. E., Renne, P. R., Montañez, I. P., Currie, B.S. 2011. A basal dinosaur from the dawn of the dinosaur era in Southwestern Pangaea. Science 331 (6014):206-210. https://doi.org/10.1126/science.1198467
 
Müller, R. T., Dias-da-Silva, S. 2019. Taxon sample and character coding deeply impact unstable branches in phylogenetic trees of dinosaurs, Historical Biology, 31:8, 1089-1092. https://doi.org/10.1080/08912963.2017.1418341
 
Müller, R. T, Langer, M. C., Dias-da-Silva, S. 2018. An exceptionally preserved association of complete dinosaur skeletons reveals the oldest long-necked sauropodomorphs. Biology Letters 14 (11): 20180633. https://doi.org/10.1098/rsbl.2018.0633
 
Nesbitt, S. J. 2011. The early evolution of archosaurs: relationships and the origin of major clades.  Bulletin of the American Museum of Natural History 352:1-292. https://doi.org/10.1206/352.1
 
Nesbitt, S. J., Irmis, R. B., Parker, S. 2007. A critical re-evaluation of the Late Triassic dinosaur taxa of North America. Journal of Systematic Palaeontology 5(2): 209-243. https://doi.org/10.1017/S1477201907002040
 
Nesbitt, S. J, Barrett, P. M., Werning, S., Sidor, C. A., Charig, A. J. 2013. The oldest dinosaur? A Middle Triassic dinosauriform from Tanzania. Biology Letters 9 (1): 20120949. https://doi.org/10.1098/rsbl.2012.0949
 
Nesbitt, S. J., Butler, R. J., Ezcurra, M. D., Barrett, P. M., Stocker, M. R., Angielczyk, K. D., Smith, R. M. H., Sidor, C. A., Niedźwiedzki, G., Sennikov, A. G., Charig, A. J. 2017. The earliest bird-line archosaurs and the assembly of the dinosaur body plan. Nature 544 (7651): 484-487. https://doi.org/10.1038/nature22037
 
Niedźwiedzki, G., Brusatte, S. L., Sulej, T., Butler, R. J. 2015. Basal dinosauriform and theropod dinosaurs from the mid–late Norian (Late Triassic) of Poland: implications for Triassic dinosaur evolution and distribution. Palaeontology 57(6): 1121-1142. https://doi.org/10.1111/pala.12107
 
Pacheco, C., Müller, R. T., Langer, M. C., Pretto, F. A., Kerber, L., Dias da Silva, S. D. 2019. Gnathovorax cabreirai: a new early dinosaur and the origin and initial radiation of predatory dinosaurs. PeerJ 7:e7963. https://doi.org/10.7717/peerj.7963
 
Parry, L. A., Baron, M. G., Vinter, J. 2017. Multiple optimality criteria support Ornithoscelida. Royal Society Open Science 2017(4):170833. https://doi.org/10.1098/rsos.170833
 
Pretto, F. A., Langer, M. C., Schultz, C. L. 2019. A new dinosaur (Saurischia: Sauropodomorpha) from the Late Triassic of Brazil provides insights on the evolution of sauropodomorph body plan. Zoological Journal of the Linnean Society 185(2): 388-416. https://doi.org/10.1093/zoolinnean/zly028
 
Seeley, H. G. 1887. On the classification of the fossil animals commonly named Dinosauria. Proceedings of the Royal Society of London 43:165-171. https://doi.org/10.1098/rspl.1887.0117
 
Sereno, P. C. 2005. The logical basis of phylogenetic taxonomy. Systematic Biology 54:595–619. https://doi.org/10.1080/106351591007453

Sereno, P. C., Martínez R. N., Alcober, O. A. 2013. Osteology of Eoraptor lunensis (Dinosauria, Sauropodomorpha). Basal sauropodomorphs and the vertebrate fossil record of the Ischigualasto Formation (Late Triassic: Carnian-Norian) of Argentina. Journal of Vertebrate Paleontology Memoir 12: 83-179. https://doi.org/10.1080/02724634.2013.820113
 
Sennikov, A. G. 1988. Novyye rauizukhidy iz triasa yevropeyskoy chasti SSSR. Paleontol. Zhurn 1990 (2): 124-128.
 
  


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