Implications of the Newark Supergroup-based astrochronology and geomagnetic polarity time scale (Newark-APTS) for the tempo and mode of the early diversification of the Dinosauria

Olsen, Paul E.; Kent, Dennis V.; Whiteside, Jessica H.

doi:10.1017/s1755691011020032

Cited by 101 publications

(90 citation statements)

References 148 publications

(425 reference statements)

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“…At a larger scale, floral data also shows a strong pattern of latitude-related provinciality, with time-transgressive microfloral assemblages being characteristic of low to higher latitudinal sedimentary basin successions (32) resulting from the northward translation of central Pangea, paralleling the pattern observed in larger vertebrates (2). Because the ranges of pollen and spores is often used for long range biostratigraphic correlation, there has been a strong tendency to conflate these biogeographic patterns with a biostratigraphic (i.e., temporal) signal in the absence, or even in the face of, strong, biostratigraphically independent means of temporal correlation (e.g., ref.…”

Section: Discussionmentioning

confidence: 95%

Climatically driven biogeographic provinces of Late Triassic tropical Pangea

Whiteside

Grogan

Olsen

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Although continents were coalesced into the single landmass Pangea, Late Triassic terrestrial tetrapod assemblages are surprisingly provincial. In eastern North America, we show that assemblages dominated by traversodont cynodonts are restricted to a humid 6°equatorial swath that persisted for over 20 million years characterized by "semiprecessional" (approximately 10,000-y) climatic fluctuations reflected in stable carbon isotopes and sedimentary facies in lacustrine strata. More arid regions from 5-20°N preserve procolophonid-dominated faunal assemblages associated with a much stronger expression of approximately 20,000-y climatic cycles. In the absence of geographic barriers, we hypothesize that these variations in the climatic expression of astronomical forcing produced latitudinal climatic zones that sorted terrestrial vertebrate taxa, perhaps by excretory physiology, into distinct biogeographic provinces tracking latitude, not geographic position, as the proto-North American plate translated northward. Although the early Mesozoic is usually assumed to be characterized by globally distributed land animal communities due to of a lack of geographic barriers, strong provinciality was actually the norm, and nearly global communities were present only after times of massive ecological disruptions.biotic provinciality | Cynodontia | orbital forcing | Procolophonidae | latitudinal gradient G eographic and climatic barriers are among the main constraints on the distribution of organisms. During the Late Triassic, Pangea lacked significant geographic barriers nearly pole-to-pole, and was warm and equable without glaciation or sea ice (1). Nonetheless, when correlated temporally by nonbiostratigraphic means, diverse Late Triassic continental faunal and floral assemblages display dramatic differences across paleolatitude (e.g., refs. 2-4) (Fig. 1). Although the equator-to-pole temperature gradients may have been relatively weak, Milankovitchtype climatic variability expressed in precipitation and evaporation was nonetheless very important (5-8). Then, as now (9,10), this scale of temporal variability may have played a critical role in structuring terrestrial communities, and thus early Mesozoic sequences provide a unique window into the link between climate variability and biotic provinciality.Here, we focus on the tropical regions of Late Triassic central Pangea and the role of traversodont cynodonts (basal synapsids) and procolophonids (parareptiles) as possible ecologically equivalent herbivores (Fig. 2) under different climatic regimes. We test the correlation between climate variability and biotic provinces within narrow swaths of time constrained by astrochronology, paleomagnetic polarity stratigraphy, and paleomagnetically determined plate position from long [>5 million years (My)] lacustrine and associated fluvial records spanning 30°of paleolatitude. We show that faunal composition tracks different modes of orbitally forced climate variability that maintained Pangean faunal provinces and suggest that this may...

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Section: Discussionmentioning

confidence: 95%

Climatically driven biogeographic provinces of Late Triassic tropical Pangea

Whiteside

Grogan

Olsen

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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“…Ghost lineages derived from phylogenies indicate that numerous ornithischian lineages must have been present at this time [17], but only three Late Triassic taxa are known from the first 30 Myr of the clade's history (Eocursor, from South Africa; and Pisanosaurus and an unnamed heterodontosaurid from Argentina), each based on incomplete singleton specimens [9, 23,24]. In each case, either the phylogenetic affinities of the taxon or its geological age have been challenged: for example, it has been suggested that one of these specimens (Pisanosaurus) is not an ornithischian at all, whereas Eocursor and the unnamed Argentinean heterodontosaurid have been suggested to be derived from strata of Early Jurassic age [25]. Consequently, ornithischians have been regarded as exceptionally rare faunal components during the Late Triassic and restricted geographically to the middle-high latitudinal regions of southern Pangaea [1][2][3]9].…”

Section: Discussionmentioning

confidence: 99%

A palaeoequatorial ornithischian and new constraints on early dinosaur diversification

et al. 2014

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Current characterizations of early dinosaur evolution are incomplete: existing palaeobiological and phylogenetic scenarios are based on a fossil record dominated by saurischians and the implications of the early ornithischian record are often overlooked. Moreover, the timings of deep phylogenetic divergences within Dinosauria are poorly constrained owing to the absence of a rigorous chronostratigraphical framework for key Late Triassic-Early Jurassic localities. A new dinosaur from the earliest Jurassic of the Venezuelan Andes is the first basal ornithischian recovered from terrestrial deposits directly associated with a precise radioisotopic date and the first-named dinosaur from northern South America. It expands the early palaeogeographical range of Ornithischia to palaeoequatorial regions, an area sometimes thought to be devoid of early dinosaur taxa, and offers insights into early dinosaur growth rates, the evolution of sociality and the rapid tempo of the global dinosaur radiation following the end-Triassic mass extinction, helping to underscore the importance of the ornithischian record in broad-scale discussions of early dinosaur history.

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“…TS III was deposited under relatively arid climatic conditions and is of Norian and Rhaetian age. Its age is constrained by palaeomagnetic correlation to the Newark basin astrochronology and marine sequences (Kent and Olsen 1999;Muttoni et al 2004;Olsen et al 2011). TS IV conformably overlies TS III and consists of the late Rhaetian top member of the Blomidon Formation and (overlying the North Mountain Basalt) the McCoy Brook Formation, which is of latest Rhaetian to Hettangian (and possibly younger) age.…”

Section: [Traduit Par La Redaction]mentioning

confidence: 99%

Stratigraphic and temporal context and faunal diversity of Permian-Jurassic continental tetrapod assemblages from the Fundy rift basin, eastern Canada

Sues

Olsen

2015

atgeol

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The Fundy basin in Nova Scotia and New Brunswick is the largest exposed rift basin of the Newark Supergroup and also extends beneath the Bay of Fundy. Its strata can be divided into four tectonostratigraphic sequences (TS). TS I is represented by the probably Permian Honeycomb Point Formation and possibly the Lepreau Formation. TS II includes the Wolfville Formation with the probably Middle Triassic Economy Member and the early Late Triassic Evangeline Member. These members have yielded markedly different assemblages of continental tetrapods. TS III comprises most of the Blomidon Formation, which is Norian to Rhaetian in age. The Blomidon Formation has yielded few skeletal remains of tetrapods to date but many tetrapod tracks. TS IV includes the late Rhaetian top of the Blomidon Formation and the McCoy Brook Formation, which overlies the North Mountain Basalt and is latest Rhaetian and earliest Jurassic (Hettangian) in age. The McCoy Brook Formation has yielded a diversity of continental tetrapods and lacks any of the characteristic Late Triassic forms. Recent work has correlated the Global Boundary Stratotype Section and Point (GSSP) for the base of the Jurassic (Hettangian) to a level well above the North Mountain Basalt. Thus most of the tetrapod fossils from the McCoy Brook Formation are latest Rhaetian in age, but the higher horizon with skeletal remains of sauropodomorph dinosaurs may be earliest Hettangian in age. The Fundy basin preserves the only known, stratigraphically tightly constrained record of the profound biotic changes in continental ecosystems across the Triassic-Jurassic transition.

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Implications of the Newark Supergroup-based astrochronology and geomagnetic polarity time scale (Newark-APTS) for the tempo and mode of the early diversification of the Dinosauria

Cited by 101 publications

References 148 publications

Climatically driven biogeographic provinces of Late Triassic tropical Pangea

Climatically driven biogeographic provinces of Late Triassic tropical Pangea

A palaeoequatorial ornithischian and new constraints on early dinosaur diversification

Stratigraphic and temporal context and faunal diversity of Permian-Jurassic continental tetrapod assemblages from the Fundy rift basin, eastern Canada

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