The paleoclimatic context for South American Triassic vertebrate evolution

MANCUSO, ADRIANA CECILIA; BRUNO LUDOVICO DIHL HORN; BENAVENTE, CECILIA ANDREA; IRMIS, RANDALL

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2021 vol. 110 p. 1 - 26

0895-9811

The Triassic Period was the setting for the origin and early diversification of Mesozoicecosystems after the end-Permian mass extinction. The study of the Triassic is essential tounderstand the evolution of non-marine Mesozoic ecosystems, particularly the vertebratecomponents and their climatic context. During this time, the configuration of thesupercontinent Pangea, which was unique (e.g., the only time since the origin of life that aglobal supercontinent spread across the equator) in the earth´s paleobiogeographic history, isone of the factors that characterized the period. This paleogeographic configuration combinedResponse to Reviewerswith a high global sea level and no polar ice caps would have had an extraordinary effect onthe global climate. Multiple sudden climate events occurred during this time, such as largeigneous province (LIP) eruptions, including two that had a major part to play incaused themajor mass extinctions that bracket the Triassic Period. Against this backdrop, a number ofmodern vertebrate clades originated on land, including lissamphibians, lepidosaurs, turtles,dinosaurs, and mammaliaforms. To test the link between climatic and evolutionary events,we compiled paleoclimatic data from Argentinian, Brazilian, Bolivian, and Chilean Triassicnon-marine vertebrate-bearing strata to discuss observed paleoclimatic changes and theirinfluence on vertebrate evolution in South America during this time. Fluctuating climateconditions dominated the western Gondwana Triassic, with arid to semiarid conditions duringEarly Triassic with marked humid seasonal fluctuation in the continental interior, theseasonal semiarid condition of the Middle Triassic shows more humid seasonality than EarlyTriassic, and the Late Triassic was dominated by seasonal sub-humid conditions with one ormore semi-arid intervals, particularly in the interior. The contrastComparisons of the TriassicSouth American vertebrate fossil record and this paleoclimate record show striking patterns,however better geochronologic control, paleoclimate proxy records, and sample fossilbearingstrata are necessary to understand these trends.