A new fossil assemblage shows that large angiosperm trees grew in North America by the Turonian (Late Cretaceous)

Jud, Nathan A.; D’Emic, Michael D.; Williams, Scott A.; Mathews, Josh C.; Tremaine, Katie; Bhattacharya, Janok P.

doi:10.1126/sciadv.aar8568

Cited by 19 publications

(14 citation statements)

References 38 publications

(45 reference statements)

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“…In contrast, gymnosperms appeared well before angiosperms in the Devonian (∼380 Ma) and flourished in diversity during the Mesozoic ( 14 , 32 – 34 ). The fossil record shows a sudden and rapid increase in diversity and geographic spread of angiosperms since the middle Cretaceous ( 18 , 19 , 35 – 40 ), which resulted in the ecological dominance, in terms of species richness, of flowering plants observed in most terrestrial ecosystems today ( 41 – 46 ). As a consequence, it is widely assumed that angiosperms underwent such an ecological and evolutionary diversification that they outcompeted and outnumbered other land plants in terms of richness ( 18 , 19 , 35 – 46 ).…”

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confidence: 99%

“…The fossil record shows a sudden and rapid increase in diversity and geographic spread of angiosperms since the middle Cretaceous ( 18 , 19 , 35 – 40 ), which resulted in the ecological dominance, in terms of species richness, of flowering plants observed in most terrestrial ecosystems today ( 41 – 46 ). As a consequence, it is widely assumed that angiosperms underwent such an ecological and evolutionary diversification that they outcompeted and outnumbered other land plants in terms of richness ( 18 , 19 , 35 – 46 ). Despite decades of scientific debate on the pattern of biotic replacements ( 16 – 24 , 35 – 39 ), the main underlying processes of speciation and extinction of gymnosperms have not been formally quantified.…”

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confidence: 99%

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The rise of angiosperms pushed conifers to decline during global cooling

Condamine

Silvestro

Koppelhus

et al. 2020

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

107

102

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Competition among species and entire clades can impact species diversification and extinction, which can shape macroevolutionary patterns. The fossil record shows successive biotic turnovers such that a dominant group is replaced by another. One striking example involves the decline of gymnosperms and the rapid diversification and ecological dominance of angiosperms in the Cretaceous. It is generally believed that angiosperms outcompeted gymnosperms, but the macroevolutionary processes and alternative drivers explaining this pattern remain elusive. Using extant time trees and vetted fossil occurrences for conifers, we tested the hypotheses that clade competition or climate change led to the decline of conifers at the expense of angiosperms. Here, we find that both fossil and molecular data show high congruence in revealing 1) low diversification rates, punctuated by speciation pulses, during warming events throughout the Phanerozoic and 2) that conifer extinction increased significantly in the Mid-Cretaceous (100 to 110 Ma) and remained high ever since. Their extinction rates are best explained by the rise of angiosperms, rejecting alternative models based on either climate change or time alone. Our results support the hypothesis of an active clade replacement, implying that direct competition with angiosperms increased the extinction of conifers by pushing their remaining species diversity and dominance out of the warm tropics. This study illustrates how entire branches on the Tree of Life may actively compete for ecological dominance under changing climates.

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confidence: 99%

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confidence: 99%

The rise of angiosperms pushed conifers to decline during global cooling

Condamine

Silvestro

Koppelhus

et al. 2020

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

107

102

View full text Add to dashboard Cite

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“…Many are comparable in size and complexity to newly discovered leaves from the Turonian Mancos Shale Formation which have been attributed to trees (Jud et al . ). This would make the Redmond flora slightly older, assuming the relative dating of the formation is accurate (see Geological Setting, above).…”

Section: Discussionmentioning

confidence: 97%

“…In this regard, the discovery and scoring of new palaeofloras (Jud et al . ) remains an essential aspect of palaeoclimatology based on biological proxies.…”

Section: Discussionmentioning

confidence: 99%

Palaeoclimatic reconstruction for a Cenomanian‐aged angiosperm flora near Schefferville, Labrador

Demers‐Potvin

Larsson

2019

Palaeontology

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An understanding of local and regional climate trends is essential to investigate the remarkable angiosperm radiation that happened during the Albian–Cenomanian transition. However, many of the inland depositional environments pioneered by the first modern angiosperms are poorly represented in the fossil record. Eastern Canada, in particular, has a very poor Mesozoic record. In this paper, we present the first multivariate palaeoclimate analysis (CLAMP) for the environment of a geologically isolated woody dicot dominated flora found in the Redmond no.1 mine, Labrador, near Schefferville, with an estimated Cenomanian age. It reveals that the Redmond flora would have experienced a mean annual temperature of 15.1 ± 2.1°C, one of the coolest recorded for North America at this time. These results confer the Redmond no.1 site a warm temperate and fully humid climate with a hot summer, in accordance with previous qualitative palaeoclimate estimates. This flora fits smoothly into palaeolatitudinal MAT gradients that use other Cenomanian‐estimated North American floras. Despite an inland setting, the climate analysis does not recover a significantly higher degree of seasonality than the sites to which it is compared, which agrees with established climate equability models for the Cretaceous and Palaeogene. This study also introduces 15 new morphotypes discovered in recent fieldwork. The eventual description of the species they represent may refine our dating estimates for the Redmond Formation. A greater understanding of the depositional environment and of the natural history of these angiosperms is required to improve this community's characterization, along with estimates from other proxies.

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“…Current evidence indicates that the earliest caenagnathids, including giant forms, had dispersed to North America by the Albian-Cenomanian (Makovicky and Sues 1998;Simon et al 2019). During this interval, terrestrial ecosystems in North America were undergoing drastic reorganizations, including turnovers in both the flora and fauna (Cifelli et al 1997;Sues and Averianov 2009;Makovicky 2011, 2013;Prieto-Marquez et al 2016;Jud et al 2018;Nesbitt et al 2019;Zanno et al 2019). The presence of caenagnathids in North America during this interval may have enabled them to occupy opening niches and expand in body size range.…”

Section: Caenagnathid Phylogeny and Evolutionmentioning

confidence: 99%

Caenagnathids of the Dinosaur Park Formation (Campanian) of Alberta, Canada: anatomy, osteohistology, taxonomy, and evolution

Funston

2020

Vert. Anat. Morph. Palaeo.

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Our understanding of caenagnathid anatomy, diversity, and ecology has improved considerably in the past twenty years, but numerous issues still remain. Among these, the diversity and taxonomy of caenagnathids from the Dinosaur Park Formation of Alberta, Canada, have remained problematic. Whereas some authors recognize three genera, others suggest only two were present, and there is considerable disagreement about which specimens are referable to which genus. This study aims to resolve this issue by reviewing the known specimens and using osteohistology, to establish a testable taxonomic framework of Dinosaur Park Formation caenagnathids. Numerous new specimens from all regions of the skeleton provide insight into morphological variation in caenagnathids, and three morphotypes are recognized based on a combination of morphological features and body size. Osteohistology shows that representatives in each body size class are at skeletal maturity, and therefore supports the delineation of three taxa: the smaller Citipes elegans gen. nov., the intermediate Chirostenotes pergracilis, and the larger Caenagnathus collinsi, new material of which shows it rivalled Anzu wyliei in size. However, these analyses also raise concerns about the referral of isolated material to each taxon in the absence of skeletal overlap between specimens or osteohistological analysis. Caenagnathids are consistently recovered throughout the Dinosaur Park Formation interval, and two geographic clusters of increased abundance probably reflect collection and taphonomic biases. The coexistence of three taxa was apparently facilitated by differences in both adult body size and functional morphology of the dentary and pes, which suggests that caenagnathids minimized niche overlap rather than subdividing niche space. Regardless, little is known of the exact roles caenagnathids played in Late Cretaceous ecosystems. Incorporation of the new material and taxonomic framework into a phylogenetic analysis drastically improves our understanding of the relationships between caenagnathines, and sheds light on the evolution of body size in caenagnathids and its role in their diversification.

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A new fossil assemblage shows that large angiosperm trees grew in North America by the Turonian (Late Cretaceous)

Abstract: Fossils from Utah show large flowering trees evolved at least 15 million years earlier than previously thought.

Cited by 19 publications

References 38 publications

The rise of angiosperms pushed conifers to decline during global cooling

The rise of angiosperms pushed conifers to decline during global cooling

Palaeoclimatic reconstruction for a Cenomanian‐aged angiosperm flora near Schefferville, Labrador

Caenagnathids of the Dinosaur Park Formation (Campanian) of Alberta, Canada: anatomy, osteohistology, taxonomy, and evolution

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