The Late Triassic Ischigualasto Formation at Cerro Las Lajas (La Rioja, Argentina): fossil tetrapods, high-resolution chronostratigraphy, and faunal correlations

Author(s):Show less -

Desojo, Julia B. ^{[1, 2]} ; Fiorelli, Lucas E. ^{[1, 3]} ; Ezcurra, Martin D. ^{[1, 4]} ; Martinelli, Agustin G. ^{[1, 4]} ; Ramezani, Jahandar ^[5] ; Da Rosa, Atila A. S. ^[6] ; Belen von Baczko, M. ^{[1, 4]} ; Jimena Trotteyn, M. ^{[1, 7]} ; Montefeltro, Felipe C. ^[8] ; Ezpeleta, Miguel ^{[1, 9]} ; Langer, Max C. ^[10]

Affiliation

^[1] Consejo Nacl Invest Cient & Tecn CONICET, Godoy Cruz 2290, C1425FQB, Buenos Aires, DF - Argentina

^[2] Univ Nacl La Plata, Div Paleontol Vertebrados, Fac Ciencias Nat & Museo, Paseo Bosque S-N, B1900FWA, La Plata - Argentina

^[3] Gobierno La Rioja, Paleontol Vertebrados, Ctr Reg Invest Cient & Transferencia Tecnol La Ri, UNLaR, SEGEMAR, UNCa, CONICET, Entre Rios & Mendoza S-N, RA-5301 Anillaco, Provincia De La - Argentina

^[4] Museo Argentino Ciencias Nat Bernardino Rivadavia, Secc Paleontol Vertebrados, Av Angel Gallardo 470, C1405DJR, Buenos Aires, DF - Argentina

^[5] MIT, Earth Atmospher & Planetary Sci, 77 Massachusetts Ave, Cambridge, MA 02139 - USA

^[6] Univ Fed Santa Maria, Ctr Ciencias Nat & Exatas, Dept Geociencias, Lab Estratig & Paleobiol, BR-97105900 Santa Maria, RS - Brazil

^[7] Univ Nacl San Juan, Inst Geol CIGEOBIO, Dept Biol, Dept Geol, Av Ignacio de la Rosa 590 Oeste, J5402DCS, San Juan - Argentina

^[8] Univ Estadual Paulista, Lab Paleontol & Evolucao Ilha Solteira, Campus Ilha Solteira, BR-15385000 Ilha Solteira, SP - Brazil

^[9] Univ Nacl Cordoba, Ctr Invest Ciencias Tierra CICTERRA, Av Velez Sarsfield 1611, Ciudad Univ, X5016GCA, Cordoba - Argentina

^[10] Univ Sao Paulo, Dept Biol, FFCLRP, Av Bandeirantes 3900, Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 10, n. 1 JUL 29 2020.
• Web of Science Citations: 1

Abstract

Present knowledge of Late Triassic tetrapod evolution, including the rise of dinosaurs, relies heavily on the fossil-rich continental deposits of South America, their precise depositional histories and correlations. We report on an extended succession of the Ischigualasto Formation exposed in the Hoyada del Cerro Las Lajas (La Rioja, Argentina), where more than 100 tetrapod fossils were newly collected, augmented by historical finds such as the ornithosuchid Venaticosuchus rusconii and the putative ornithischian Pisanosaurus mertii. Detailed lithostratigraphy combined with high-precision U-Pb geochronology from three intercalated tuffs are used to construct a robust Bayesian age model for the formation, constraining its deposition between 230.2 +/- 1.9 Ma and 221.4 +/- 1.2 Ma, and its fossil-bearing interval to 229.20+0.11/-0.15-226.85+1.45/-2.01 Ma. The latter is divided into a lower Hyperodapedon and an upper Teyumbaita biozones, based on the ranges of the eponymous rhynchosaurs, allowing biostratigraphic correlations to elsewhere in the Ischigualasto-Villa Union Basin, as well as to the Parana Basin in Brazil. The temporally calibrated Ischigualasto biostratigraphy suggests the persistence of rhynchosaur-dominated faunas into the earliest Norian. Our ca. 229 Ma age assignment to Pi. mertii partially fills the ghost lineage between younger ornithischian records and the oldest known saurischians at ca. 233 Ma. (AU)

• FAPESP's process: 14/03825-3 - The origin and rise of dinosaurs in Gondwana (late Triassic - early Jurassic)
• Grantee: Max Cardoso Langer
• Support Opportunities: Research Projects - Thematic Grants