Time and Place: About 235 to 234 million years ago, in the Carnian of the Late TriassicĀ
Lagerpeton is known from the ChaƱares Formation in La Rioja, ArgentinaĀ
Physical Description: Lagerpeton was named as the Rabbit Reptile, and for good reason - in a lot of ways, it represents a decent attempt by reptiles in trying to do the whole hoppy-hop thing. You might think that it resembles Scleromochlus in that way, and youād be right! Scleromochlus and Lagerpeton are close cousins, but one is on the line towards Pterosaurs - Scleromochlus - and the other is on the line towards dinosaurs - Lagerpeton. So, hopping around was an early feature that all Ornithodirans (Dinosaurs, Pterosaurs, and those closest to them) shared. Lagerpeton itself was about 70 centimeters in length, with most of that length represented as tail; it was slender and lithe, built for moving quickly through its environment. It had a small head, a long neck, and a thin body. While it had long legs, it also had somewhat long arms, and while it may have been able to walk on all fours it also would have been able to walk on two legs alone. It was digitigrade, walking only on its toes, making it an even faster animal. Its back was angled to help it in hopping and running through its environment, and its small pelvis gave it more force during hip extension while jumping. In addition to all of this, it basically only really rested its weight on two toes - giving it even more hopping ability! As a small early bird-line reptile, it would have been covered in primitive feathers all over its body (protofeathers), though what form they took we do not know.Ā
By Scott Reid
Diet: As an early dinosaur relative, itās more likely than not that Lagerpeton was an omnivore, though this is uncertain as its head and teeth are not known at this time.
Behavior: Lagerpeton would have been a very skittish animal, being so small in an environment of so many kinds of animals - and as such, that hopping and fast movement ability would have aided it in escaping and moving around its environment, avoiding predators and reaching new sources of food (and, potentially, chasing after smaller food itself). Lagerpeton may have also been somewhat social, moving in small groups, potentially families, to escape the predators and chase after prey together, given its common nature in its environment. As an archosaur, Lagerpeton was more likely than not to take care of its young, though we donāt know how or to what extent. The feathers it had would have been primarily thermoregulatory, and as such, they would have helped it maintain a constant body temperature - making it a very active, lithe animal.Ā
Ecosystem: Lagerpeton lived in the ChaƱares environment, a diverse and fascinating environment coming right after the transition from the Middle to Late Triassic epochs. Given that the first true dinosaurs are probably from the start of the Late Triassic, this makes it a hotbed for understanding the environments that the earliest dinosaurs evolved in. Since Lagerpeton is a close dinosaur relative, this helps contextualize its place within its evolutionary history. This environment was a floodplain, filled with lakes that would regularly flood depending on the season. There were many seed ferns, ferns, conifers, and horsetails. Many different animals lived here with Lagerpeton, including other Dinosauromorphs like the Silesaurid Lewisuchus/Pseudolagosuchus and the Dinosauriform Marasuchus/Lagosuchus. There were crocodilian relatives as well, such as the early suchian Gracilisuchus and the Rauisuchid Luperosuchus. There were also quite a few Proterochampsids, such as Tarjadia, Tropidosuchus, Gualosuchus, and Chanaresuchus. Synapsids also put in a good show, with the Dicynodonts Jachaleria and Dinodontosaurus, as well as Cynodonts like Probainognathus and Chiniquodon, and the herbivorous Massetognathus. Luperosuchus would have definitely been a predator Lagerpeton would have wanted to get away from - fast!Ā
By Ripley Cook
Other: Lagerpeton is one of our earliest derived Dinosauromorphs, showing some of the earliest distinctions the dinosaur-line had compared to other archosaurs. Lagerpeton was already digitigrade - an important feature of Dinosaurs - as shown by its tracks, called Prorotodactylus. These tracks also showcase that dinosaur relatives were around as early as the Early Triassic - and that their evolution, and the rapid diversification of archosauromorphs in general, was a direct result of the end-Permian extinction.
~ By Meig Dickson
Sources Under the CutĀ
Arcucci, A. 1986. New materials and reinterpretation of Lagerpeton chanarensis Romer (Thecodontia, Lagerpetonidae nov.) from the Middle Triassic of La Rioja, Argentina. Ameghiniana 23 (3-4): 233-242.
Arcucci, A. B. 1987. Un nuevo Lagosuchidae (Thecodontia-Pseudosuchia) de la fauna de los ChaƱares (Edad Reptil ChaƱarense, Triasico Medio), La Rioja, Argentina. Ameghiniana 24: 89 - 94.
Arcucci, A., C. A. Mariscano. 1999. A distinctive new archosaur from the Middle Triassic (Los ChaƱares Formation) of Argentina. Journal of Vertebrate Paleontology 19: 228 - 232.
Bittencourt, J. S., A. B. Arcucci, C. A. Marsicano, M. C. Langer. 2014. Osteology of the Middle Triassic archosaur Lewisuchus admixtus Romer (ChaƱares Formation, Argentina), its inclusivity, and relationships amongst early dinosauromorphs. Journal of Systematic Palaeontology: 1 - 31.
Brusatte, S. L., G. Niedzwiedzki, R. J. Butler. 2011. Footprints pull origin and diversification of dinosaur stem lineage deep into Early Triassic. Proceedings of the Royal Society B: Biological Sciences 278 (1708): 1107 - 1113.
Ezcurra, M. D. 2006. A review of the systematic position of the dinosauriform archosaur Eucoelophysis baldwini Sullivan & Lucas, 1999 from the Upper Triassic of New Mexico, USA. Geodiversitas 28(4):649-684.
Ezcurra, M. D. 2016. The phylogenetic relationships of basal archosauromorphs, with an emphasis on the systematics of proterosuchian archosauriformes. PeerJ 4: e1778.
Fechner, R. 2009. Morphofunctional evolution of the pelvic girdle and hindlimb of DInosauromorpha on the lineage to Sauropoda (Thesis). Ludwigs Maximillians Universita.
Fiorelli, L. E., S. Rocher, A. G. Martinelli, M. D. Ezcurra, E. Martin Hechenleitner, M. Ezpeleta. 2018. Tetrapod burrows from the Middle-Upper Triassic ChaƱares Formation (La Rioja, Argentina) and its palaeoecological implications. Palaeogeography, Palaeoclimatology, Palaeoecology 496: 85 - 102.
Kammerer, C. F., S. J. Nesbitt, N. H. Shubin. 2012. The first Silesaurid Dinosauriform from the Late Triassic of Morocco. Acta Palaeontological Polonica 57 (2): 277.
Kent, D. V., P. S. Malnis, C. E. Colombi, A. A. Alcober, R. N. Martinez. 2014. Age constraints on the dispersal of dinosaurs in the Late Triassic from magnetochronology of the Los Colorados Formation (Argentina). Proceedings of the National Academy of Sciences 111: 7958 - 7963.
Irmis, R. B., S. J. Nesbitt, K. Padian, N. D. Smith, A. H. Turner, D. T. Woody, and A. Downs. 2007. A Late Triassic dinosauromorph assemblage from New Mexico and the rise of dinosaurs. Science 317:358-361.
Jenkins, F. A. 1970. The ChaƱares (Argentina) Triassic reptile fauna. VII. The postcranial skeleton of the traversodontid Massetognathus pascuali (Therapsida, Cyondontia). Breviora 352: 1 - 28.
Langer, M. C., S. J. Nesbitt, J. S. Bittencourt, R. B. Irmis. 2013. Non-dinosaurian Dinosauromorphs. Geological Society London, Special Publications. 379 (1): 157 - 186.
Marsh, A. D. 2018. A new record of Dromomeron romeri Irmis et al., 2007 (Lagerpetidae) from the Chinle Formation of Arizona, U.S.A. PaleoBios 35:1-8.
Marsicano, C. A., R. B. Irmis, A. C. Mancuso, R. Mundil, F. Chemale. 2016. The precise temporal calibration of dinosaur origins. Proceedings of the National Academy of Sciences of the United States of AMerica 113 (3): 509 - 513.
Martz, J. W., and B. J. Small. 2019. Non-dinosaurian dinosauromorphs from the Chinle Formation (Upper Triassic) of the Eagle Basin, northern Colorado: Dromomeron romeri (Lagerpetidae) and a new taxon, Kwanasaurus williamparkeri (Silesauridae). PeerJ 7:e7551:1-71.
Nesbitt, S. J., R. B. Irmis, W. G. Parker, N. D. Smith, A. H. Turner and T. Rowe. 2009. Hindlimb osteology and distribution of basal dinosauromorphs from the Late Triassic of North America. Journal of Vertebrate Paleontology 29(2):498-516.
Nesbitt, S. J. 2011. The early evolution of archosaurs: relationships and the origin of major clades. Bulletin of the American Museum of Natural History 353:1-292.
Perez Loinaze, V. S., E. I. Vera, L. E. Fiorelli, J. B. Desojo. 2018. Palaeobotany and palynology of coprolites from the Late Triassic ChaƱares Formation of Argentina: implications for vegetation provinces and the diet of dicynodonts. Palaeogeography, Palaeoclimatology, Palaeoecology 502: 31 - 51.
Rogers, R. R., A. B. Arcucci, F. Abdala, P. C. Sereno, C. A. Forster, C. L. May. 2001. Paleoenvironment and taphonomy of the ChaƱares Formation tetrapod assemblage (Middle Triassic), northwestern Argentina: spectacular preservation in volcanogenic concretions. Palaios 16: 461 - 481.
Romer, A. S. 1966. Ā The ChaƱares (Argentina) Triassic reptile fauna. I. Introduction. Breviora 247: 1 - 14.
Romer, A. S. 1966. Ā The ChaƱares (Argentina) Triassic reptile fauna. II. Sketch of the geology of the Rio-ChaƱares-Rio Gualo Region. Breviora 252: 1 - 20.
Romer, A. S. 1967. The ChaƱares (Argentina) Triassic reptile fauna. III. Two new gomphodonts, Massetognathus pascuali and M. teruggii. Breviora 264: 1 - 25.
Romer, A. S. 1968. The ChaƱares (Argentina) Triassic reptile fauna. IV. The dicynodont fauna. Breviora 295: 1 - 25.
Romer, A. S. 1969. The ChaƱares (Argentina) Triassic reptile fauna. V. A new chiniquodontid cynodont, Probelesodon lewisi - cynodont ancestry. Breviora 333: 1 - 24.
Romer, A. S. 1970. The ChaƱares (Argentina) Triassic reptile fauna. VI. A chiniquodont cynodont with an incipient squamosal-dentary jaw articulation. Breviora 344: 1 - 18.
Romer, A. S. 1971. The ChaƱares (Argentina) Triassic reptile fauna. VIII. A fragmentary skull of a large thecodont, Luperosuchus fractus. Breviora 373: 1 - 8.
Romer, A. S. 1971. The ChaƱares (Argentina) Triassic reptile fauna. IX: The Chanares Formation. Breviora 377: 1 - 8.
Romer, A. S. 1971. The ChaƱares (Argentina) Triassic reptile fauna. X. Two new but incompletely known long-limbed pseudosuchians. Breviora 378:1-10.
Romer, A. S. 1971. The ChaƱares (Argentina) Triassic reptile fauna. XI. Two new long-snouted thecodonts, Chanaresuchus and Gualosuchus. Breviora 379: 1 - 22.
Romer, A. S. 1972. The ChaƱares (Argentina) Triassic reptile fauna. XII. The post cranial skeleton of the thecodont Chanaresuchus. Breviora 385: 1 - 21.
Romer, A. S. 1972. The ChaƱares (Argentina) Triassic reptile fauna. XIII. A fragmentary skull of a large thecodont, Luperosuchus fractus. Breviora 389: 1 - 8.
Romer, A. S. 1972. The ChaƱares (Argentina) Triassic reptile fauna. Lewisuchus admixtus, gen. et sp. Nov., a further thecodont from the ChaƱares beds. Breviora 390: 1 - 13.
Romer, A. S. 1972. The ChaƱares (Argentina) Triassic reptile fauna. XV. Further remains of the thecodonts Lagerpeton and Lagosuchus. Breviora 394: 1 - 7.
Romer, A. S. 1972. The ChaƱares (Argentina) Triassic reptile fauna. XVI. Thecodont classification. Breviora 395:1-24.
Romer, A. S. 1972. The ChaƱares (Argentina) Triassic reptile fauna. XVII. The ChaƱares gomphodonts. Breviora 396: 1 - 9.
Romer, A. S. 1973. The ChaƱares (Argentina) Triassic reptile fauna. XVIII. Probelesodon minor, a new species of carnivorous cynodont; family Probainognathidae nov. Breviora 401: 1 - 4.
Romer, A. S., and A. D. Lewis. 1973. The ChaƱares (Argentina) Triassic reptile fauna. XIX. Postcranial materials of the cynodonts Probelesodon and Probainognathus. Breviora 407: 1 - 26.
Romer, A. S. 1973. The ChaƱares (Argentina) Triassic reptile fauna. XX. Summary. Breviora 413: 1 - 20.
Sereno, P. C., and A. B. Arcucci. 1994. Dinosaurian precursors from the Middle Triassic of Argentina: Marasuchus lilloensis, gen. nov. Journal of Vertebrate Paleontology 14(1):53-73.
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