Skip to main content Skip to main navigation menu Skip to site footer
Type: Article
Published: 2018-03-07
Page range: 149–158
Abstract views: 178
PDF downloaded: 1

Ingroup relationships of Lagerpetidae (Avemetatarsalia: Dinosauromorpha): a further phylogenetic investigation on the understanding of dinosaur relatives

Centro de Apoio à Pesquisa da Quarta Colônia, Universidade Federal de Santa Maria, Rua Maximiliano Vizzotto, 598, 97230-000 São João do Polêsine, RS, Brazil. Programa de Pós Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, 97105-120 Santa Maria, RS, Brazil
Laboratório de Paleontologia, Universidade de São Paulo, 14040-901, Ribeirão Preto, SP, Brazil.
Centro de Apoio à Pesquisa da Quarta Colônia, Universidade Federal de Santa Maria, Rua Maximiliano Vizzotto, 598, 97230-000 São João do Polêsine, RS, Brazil.
Reptilia cladistics basal dinosauromorpha late triassic paleobiogeography phylogeny


Despite representing a key-taxon in dinosauromorph phylogeny, Lagerpertidae is one of the most obscure and enigmatic branches from the stem that leads to the dinosaurs. Recent new findings have greatly increased our knowledge about lagerpetids, but no phylogenetic analysis has so far included all known members of this group. Here, we present the most inclusive phylogenetic study so far conducted for Lagerpetidae. Phylogenetic analyses were performed based on three independent data matrixes. In two of them, Lagerpeton chanarensis Romer, 1971 is the sister taxon to all other known Lagerpetidae, whereas Ixalerpeton polesinensis Cabreira et al., 2016 is in a sister group relationship with a clade that includes PVSJ 883 and Dromomeron. Conversely, the other analysis supports an alternative topology, where I. polesinensis is the sister taxon to either L. chanarensis or all other Lagerpetidae. Although coeval and geographically close, I. polesinensis and PVSJ 883 do not form a clade exclusive of other lagerpetids. As previously suggested D. gigas Martínez, Apaldetti, Correa & Abelín, 2016 is the sister taxon of D. romeri Irmis et al., 2007. The phylogenetic analyses also indicate that the earliest lagerpetids are restricted to southwestern Pangea, whereas later forms spread across the entire western portion of the supercontinent. Finally, quantification of the codified characters of our analysis reveals that Lagerpetidae is one of the poorest known among the Triassic dinosauromorph groups in terms of their anatomy, so that new discoveries of more complete specimens are awaited to establish a more robust phylogeny.



  1. Apaldetti, C., Pol, D. & Yates, A. (2013) The postcranial anatomy of Coloradisaurus brevis (Dinosauria: Sauropodomorpha) from the Late Triassic of Argentina and its phylogenetic implications. Palaeontology, 56, 277–301.

    Arcucci, A. (1987) Un nuevo Lagosuchidae (Thecodontia-Pseudosuchia) de la fauna de Los Chanares (edad reptil Chanarense, Triásico Medio), La Rioja, Argentina. Ameghiniana, 24, 89–94.

    Baron, M.G., Norman, D.B. & Barrett, P.M. (2017a) A new hypothesis of dinosaur relationships and early dinosaur evolution. Nature, 543, 501–506.

    Baron, M.G., Norman, D.B. & Barrett, P.M. (2017b) Baron et al. reply. Nature, 551, E4–E5.

    Bonaparte, J.F. (1975) Nuevos materiales de Lagosuchus talampayensis Romer (Thecodontia-Pseudosuchia) y su significado en el origen de los Saurischia. Chañarense inferior, Triásico Medio de Argentina. Acta Geologica Lilloana, 13, 5–90.

    Broom, R. (1913) On the South African Pseudosuchian Euparkeria and allied genera. Proceedings of the Zoological Society of London, 83, 619–633.

    Cabreira, S.F., Kellner, A.W.A., Dias-da-Silva, S., Roberto-da-Silva, L., Bronzati, M., Marsola, J.C., Müller, R.T., Bittencourt, J.S., Batista, B.J., Raugust, T., Carrilho, R. & Langer, M.C. (2016) A unique Late Triassic dinosauromorph assemblage reveals dinosaur ancestral anatomy and diet. Current Biology, 26, 3090–3095.

    Dzik, J. (2003) A beaked herbivorous archosaur with dinosaur affinities from the early Late Triassic of Poland. Journal of Vertebrate Paleontology, 23, 556–574.

    Ezcurra, M.D. (2006) A review of the systematic position of the dinosauriform archosaur Eucoelophysis baldwini Sullivan and Lucas, 1999 from the Upper Triassic of New Mexico, USA. Geodiversitas, 28, 649–684.

    Ferigolo, J. & Langer, M.C. (2007) A Late Triassic dinosauriform from south Brazil and the origin of the ornithischian predentary bone. Historical Biology, 19, 23–33.

    Goloboff, P.A., Farris, J.S. & Nixon, K.C. (2008) TNT, a free program for phylogenetic nalysis. Cladistics, 24, 1–13.

    Irmis, R.B., Nesbitt, S.J., Padian, K., Smith, N.D., Turner, A.H., Woody, D. & Downs, A. (2007) A Late Triassic dinosauromorph assemblage from New Mexico and the rise of dinosaurs. Science, 317, 358–361.

    Kammerer, C., Nesbitt, S.J. & Shubin, N.H. (2012) The first basal dinosauriform (Silesauridae) from the Late Triassic of Morocco. Acta Palaeontologica Polonica, 57, 277–284.

    Langer, M.C., Ezcurra, M.D., Rauhut, O.W., Benton, M.J., Knoll, F., Mcphee, B.W., Novas, F.E., Pol, D. & Brusatte, S.L. (2017) Untangling the dinosaur family tree. Nature, 551, E1–E3.

    Leal, L.A., Azevedo, S.A., Kellner, A.W. & Da Rosa, Á.A. (2004) A new early dinosaur (Sauropodomorpha) from the Caturrita Formation (Late Triassic), Paraná Basin, Brazil. Zootaxa, 690, 1–24.

    Marsicano, C.A., Irmis, R.B., Mancuso, A.C., Mundil, R. & Chemale, F. (2016) The precise temporal calibration of dinosaur origins. Proceedings of the National Academy of Sciences, 113, 509–513.

    Martínez, R.N., Apaldetti, C., Alcober, O.A, Colombi, C.E., Sereno, P.C., Fernandez, E., Malnis, P.S., Correa, G.A. & Abelin, D. (2012) Vertebrate succession in the Ischigualasto Formation. Journal of Vertebrate paleontology, 32, 10–30.

    Martínez, R.N., Apaldetti, C., Correa, G.A. & Abelín, D. (2016) A Norian Lagerpetid Dinosauromorph from the Quebrada Del Barro Formation, Northwestern Argentina. Ameghiniana, 53, 1–13.

    Martínez, R.N., Apaldetti, C., Correa, G., Colombi, C.E., Fernandez, E., Santi Malnis, P., Praderio, A., Abelín, D., Benegas, L., Aguilar Cameo, A. & Alcober, O.A. (2015) A new late Triassic vertebrate assemblage from Northwestern Argentina. Ameghiniana, 52, 379–390.

    Martínez, 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, 206–210.

    McPhee, B.W., Bonnan, M.F., Yates, A.M., Neveling, J. & Choiniere, J.N. (2015) A new basal sauropod from the pre-Toarcian Jurassic of South Africa: evidence of niche-partitioning at the sauropodomorph—sauropod boundary? Scientific Reports, 5. [published online]

    Nesbitt, S.J. (2011) The early evolution of Archosauria: relationships and the origin of major clades. Bulletin of the American Museum of Natural History, 352, 1–292.

    Nesbitt, S.J., Butler, R.J., Ezcurra, M.D., Barret, P.M., Stocker, M.R., Angielczyk, K.D., Smoth, R.M., 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, 484–487.

    Nesbitt, S.J., Irmis, R.B., Parker, W.G., Smith, N.D., Turner, A.H. & Rowe, T. (2009) Hindlimb osteology and distribution of basal dinosauromorphs from the Late Triassic of North America. Journal of Vertebrate paleontology, 29, 498–516.

    Novas, F.E. (1996) Dinosaur monophyly. Journal of Vertebrate paleontology, 16, 723–741.

    Otero, A. & Pol, D. (2013) Postcranial anatomy and phylogenetic relationships of Mussaurus patagonicus (Dinosauria, Sauropodomorpha). Journal of Vertebrate paleontology, 33, 1138–1168.

    Romer, A.S. (1971) The Chañares (Argentina) Triassic reptile fauna. XI. Two but new incompletely known long-limbed Pseudosuchians. Breviora, 378, 1–10.

    Sarıgül, V. (2016) New basal dinosauromorph records from the Dockum Group of Texas, USA. Palaeontologia Electronica, 19, 1–13.

    Sarıgül, V. (2017) New archosauromorph fragments from the Dockum Group of Texas and assessment of the earliest dinosaurs in North America. Historical Biology, 1–17.

    Sereno, P.C. & Arcucci, A.B. (1994) Dinosaurian precursors from the Middle Triassic of Argentina: Lagerpeton chanarensis. Journal of Vertebrate paleontology, 13, 385–399.

    Small, B. (2009) A Late Triassic dinosauromorph assemblage from the Eagle Basin (Chinle Formation), Colorado, U.S.A. Journal of Vertebrate paleontology, 29, 182A.

    Sullivan, RM. & Lucas, S.G. (1999) Eucoelophysis baldwini, a new theropod dinosaur from the Upper Triassic of New Mexico, and the status of the original types of Coelophysis. Journal of Vertebrate Paleontology, 19, 81–90.

    Watson, D.M.S. (1912) Mesosuchus browni, gen. et spec. nov. Records of the Albany Museum, 2, 298–299.