Nathan A. Jud , Michael D. D’Emic, Scott A. Williams, Josh C. Mathews, Katie M. Tremaine, and also Janok Bhattacharya
The diversification of flowering plants and also marked turnover in vertebprice faunas throughout the mid-Cretaceous transcreated terrestrial communities, yet the shift is obscured by reduced terrestrial deposition attributable to high sea levels. We report a new fossil assemblage from multiple localities in the Upper Cretaceous Ferron Sandstone Member of the Mancos Shale Formation in Utah. The fossils day to the Turonian, a severely understood for interval in the terrestrial fossil record of The United States and Canada. A big silicified log (maximum kept diameter, 1.8 m; approximated elevation, ca. 50 m) is assigned to the genus Paraphyllanthoxylon; it is the biggest well-known pre-Campanian angiosperm and the earliest documented incident of an angiosperm tree even more than 1.0 m in diameter. Foliage and palynomorphs of ferns, conifers, and also angiosperms confirm the presence of combined woodland or woodland vegetation. Previously known terrestrial vertebrate remains from the Ferron Sandstone Member include fish teeth, 2 short dinosaur trackways, and a pterosaur; we report the initially turtle and also crocodilian continues to be and also an ornithopod sacrum. Previous studies show that angiosperm trees were existing by the Cenomanian, but this exploration demonstprices that angiosperm trees approaching 2 m in diameter were component of the woodland canopies throughout southern The United States and Canada by the Turonian (~92 million years ago), nearly 15 million years earlier than formerly thought.

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Terrestrial areas underwent marked transforms associated with the diversification of flowering plants throughout the mid-Cretaceous (1). Unfortunately, internationally high sea levels and diminished terrestrial deposition limit our expertise of these neighborhoods. An especially underrepresented time is the Turonian for which few localities are recognized throughout western The United States and Canada for plant and also terrestrial vertebprice fossils (2). The combination of a sporadic fossil document in western The United States and Canada and noted ecological alters means that each new discovery has actually the potential to dramatically influence our expertise of the eco-friendly alters that took area in the time of this crucial interval.
Today, flowering plants selection in size from minute herbs to massive trees. How conveniently did they come to occupy this array of morphospace? Genealogical state reconstructions indicate that the prevalent ancestor of crown-group angiosperms produced small amounts of lumber (3). Direct evidence from fossils reflects that tiny herbs developed early (4, 5) but it may have actually taken countless years for flowering plants to acquire sizes rivaling the tallest living tropical lowland also emergent trees. The fossil document of angiosperm woods is indevelopmental in part because trunk diameter is regarded tree elevation and standing biomass (6). Fossil angiosperm lumber is rare in pre-Campanian deposits, and most are small fragments (7, 8). These attributes contributed to the hypothesis that angiosperms were subordinate to gymnosperm trees in many kind of habitats (9, 10); but, events of moderately large angiosperm wood pieces (0.1 to 1 m in diameter) from Albian-Turonian deposits (11–14) imply that sampling biases can mask angiosperm physiognomic diversity and abundance in mid-Cretaceous deposits (15), as they do for several Cretaceous terrestrial vertebprice teams (2). Under this hypothesis, large angiosperm trees would certainly have been an important component of poorly sampled mid-Cretaceous communities (15).
Here, we carry a new discovery to bear on the question of once angiosperm trees attained incredibly huge size (>1 m in diameter at breastern height). By placing our findings in the bigger conmessage for fossil angiosperm woods, we display that big angiosperm trees were part of woodland canopies throughout southerly The United States and Canada (Appalachia to the eastern and Laramidia to the west) by the Turonian. In enhancement to the fossil hardwood, we report the first leaf fossils and new terrestrial vertebprice fossils from the Ferron Sandrock Member of the Mancos Shale. Our findings highlight the existing severity of geologic biases in the Upper Cretaceous North Amerihave the right to fossil document while simultaneously opening a brand-new fossiliferous horizon for remedying those biases.
Our fieldjob-related expands the fldental and vertebprice documents in the Ferron Sandstone Member of the Mancos Shale, including angiosperm macrofossils and also turtle, crocodylian, and ornithopod body fossils to currently recognized chondrichthyan (16) and also pycnodont teeth (17), pterosaur body fossils (18), and trackmethods of ornithopod (19) and therizinosaur (20) dinosaurs. The fossils explained herein are from the peak of parasequence 6 (that is, 6th from the height of the Ferron Sandstone) in sequence 2 (that is, second from the top) of Zhu et al. (21). Bentonites above and also below parasequence 6, in sequences 1 and 2 of Zhu et al. (21), constrain the age of the vertebrate and plant body fossils and also vertebprice ichnofossils to between 90.64 ± 0.25 Ma and 90.69 ± 0.34 Ma and are correlated to the Prionocyclus macombi ammonite zamong Cobban et al. (22).
A large decorticated log, ~11 m in maintained size via a maximum diameter estimate of 1.8 m, was found at 38.2°N, 110.8°W (more precise place is on file with the Bureau of Land Management). This is approximately double the size of previously documented angiosperm woods from pre-Campanian deposits global (Fig. 1). We did not collect the entire speciguys (Fig. 2A), however hand also samples and also thin sections are archived at the University of Florida (UF 19462-69143). A 3D surface model developed through photogrammetry is accessible on Morphobank ( Preservation of the trunk is variable. The core is more than 1.6 m in diameter, and complying with the partial excavation and also careful examicountry of the trunk, we estimate the diameter at 1.8 m; but, it does not show up to have actually gone through substantial taphonomic distortion on macro- or microscopic scales that would make the diameter show up larger. We approximated the stem size (tree height) at 50.8 m based on the 1.8 m in diameter estimate (at about breastern height) making use of the allometric scaling equation arisen from the cannel compendium data (23) by Niklas and Spatz (24) and 53.6 m utilizing the pantropical model of height-diameter relationships occurred from direct dimensions of tropical dicot trees by Feldpausch et al. (25). The diameter at breast elevation worth of 1.8 m is beyond the array of values in both information sets, precluding the usage of a prediction interval; yet, we safeguard our initial estimate because the empirical data used to develop these models fit a mechanistic predictive version (24).

Map of Turonian localities in western North America via angiosperm woods >10 cm in diameter and also stacked location curve reflecting the contribution of this exploration (indicated by star) to the worldwide document of Cretaceous angiosperm woods. Ages are midallude approximates. The gray location shows the maximum observed angiosperm diameter with the Cretaceous. Daburned box shows Turonian incidents shown in the map above. Incollection shows the brand-new angiosperm log in the field (Photograph Credit: M.D. D’Emic, Adelphi University). During much of the Late Cretaceous, the Western Interior Seamethod split The United States and Canada into Appalachia in the east and Laramidia in the west. Map modified from Blakey (38).

(A) Picture of the log in the area. (B) Transverse area (XS) showing diffusage porous lumber with vessels in short radial multiples of 2 to 11, development rings lacking, axial parenchyma rare, radial bands of fibers, and also rays about the very same width. (C) Tangential longitudinal section (TLS) reflecting crowded, hexagonal pits on the vessel wall. (D) TLS reflecting carefully spaced lens-shaped 2- to 4-seriate rays among elongate fibers. (E) Radial longitudinal section mirroring rows of procumbent and upideal ray parenchyma cells. (F) XS reflecting thin-walled ray cells (at left) and also medium thick-walled fibers (at right). Scale bars, 500 μm (B), 100 μm (C), 250 μm (D), 200 μm (E), and also 50 μm (F). (Photo Credits: A: M.D. D’Emic, Adelphi University; B to F: N.A. Jud, College of Florida)
We studied the anatomy of the angiosperm timber in transverse, radial longitudinal, and also TLS from a hand also sample taken from the outermost percentage of the log. The hardwood lacks distinct growth rings and also is diffuse-porous. The vessels are solitary (30%) and also in radial multiples of approximately 11, with a suppose tangential diameter of 137 μm (n = 25; SD, 30; selection, 92 to 181 μm) and also a frequency of 6.0 vessels mm−2 (Fig. 2B). The vessel aspects have actually basic perforation plates, numerous tyloses, and crowded alternate intervessel pits 11 and 12 μm across (Fig. 2C). Axial parenchyma is scanty paratracheal (Fig 2B). The rays are heterocellular and also mostly 2 to 4 seriate, through 1 to 2 rows of marginal upappropriate cells (Fig. 2, D and E). Median ray elevation is 645 μm (n = 25; SD, 299; array, 204 to 1449 μm), and also ray frequency is 7.1 mm−1. Poor conservation obscures the vessel-ray parenchyma pits. Fibers are medium thick-walled (Fig. 2F), septate, and without distinctly bordered pits. We did not observe crystals, storied framework, canals, nor cambial variants.
The fossil belongs to the genus Paraphyllanthoxylon Bailey. In virtually all attributes oboffered, this specimen condevelops to Paraphyllanthoxylon alabamense Cahoon (table S1); however, we did not observe the vessel-ray parenchyma pits, and also it has actually vessels that are arranged in longer radial multiples than oboffered in the specimens from Alabama (13). It is our judgment that these differences perform not warrant the acknowledgment of a brand-new species, so we refer the Ferron log to P. cf. alabamense. The largest reported diameter from the kind locality for that species is 0.9 m (13), although anecdotal evidence argues that tright here were additionally specimens more than 1 m in diameter (26).
Approximately 11 kilometres northwest of the huge angiosperm log, we made a small repertoire of leaf fossils from brownish gray shales (38.39°N, 110.88°W), near an build-up of Rosselia map fossils erroneously determined as sauropod dinosaur footprints in a conference abstract (27). The leaves co-take place with impressions of bivalves in a fluvial and distributary channel that is component of a wider fresh-to-brackish water lower delta ordinary atmosphere. The assemblage has isolated shoots of Elatides curvifolia (Dunker) Nathorst (Fig. 3, A and B), and also fragmentary stays of nonmonocot angiosperm leaves. The many finish angiosperm leaf is the lower percentage of a notophyllous leaf with an attached petiole (Fig. 3C). We likewise found tiny fern pieces (Fig. 3D).

(A) Leafy shoot of E. curvifolia (Dunker) Nathorst; UF 19523-70170. B) Indeterminate angiosperm leaf; UF 19523-70171. (C) Close-up of (A). (D) Isolated fern pinnule; UF 19523-70170. Scale bars, 5 mm (A to C) and 3 mm (D). (Picture Credits: N.A. Jud, University of Florida)
Vertebprice body fossils take place mostly at the base of fluvial and also distributary channels around 10 kilometres northwest of the large angiosperm log and were deposited in a fresh-to-brackish water reduced delta ordinary environment. A single shark tooth is attributable to Cretodus crassidens (Fig. 4A), a common lamnidevelop shark in Turonian Western Interior Seaway deposits (16, 28). We additionally recovered crocodylicreate teeth (BMRP 2017.8.5, BMRP 2017.8.4, and BMRP 2017.8.3; Fig. 4B), a huge (~9 cm long and ~1 cm thick) turtle scute (BMRP 2017.8.6; Fig. 4C), and a partial ornithopod sacrum (BMRP 2017.8.2; Fig. 4D).

(A) Tooth of C. crassidens BMRP 2017.8.1. (B) Crocodylidevelop teeth 2017.8.5 (left), 2017.8.4 (center), BMRP 2017.8.3 (right). (C) Dorsal turtle scute BRMP 2017.8.6. (D) Ornithopod sacrum BMRP 2017.8.2. (Photograph Credits: S.A. Williams, Burpee Museum of Natural History)
The Ferron Sandstone Member preserves fossil lumber, leaves, and both terrestrial and marine vertebrate body fossils. The incident of C. crassidens and also associated radiometrically dated bentonite beds confirms the Turonian age for the fossils. The Turonian vertebprice fossil record is sparse (2), limiting our understanding of the beginning of exceedingly varied and geographically heterogeneous (29) Campanian-Maastrichtian neighborhoods. These findings begin to fill the gap in our knowledge of mid-Cretaceous terrestrial areas in North America.
Until now, the only plant fossils well-known from the Ferron Sandstone Member were palynomorphs derived within 10 km of wright here the log reported herein is situated (30). The mixture of fungal, algal, and also fern spores, taxodiaceous conifer pollen, and palm pollen are indicative of a warm (frost-free), ever-wet climate (30). It is surpincreasing that in the exact same development where an huge angiosperm tree was uncovered, no nonmonocot angiosperm pollen types have actually yet been reported (30); however, in at leastern some instances, Paraphyllanthoxylon woods are attributable to Lauraceae (31), a family through a notoriously bad spread pollen record (32). The log described here is considerably larger than all formerly publiburned reports of angiosperm lumber from Cretaceous deposits, except for some stumps from the top Campanian of New Mexico (33). Collectively, these fossils represent the largest well-known Cretaceous angiosperms (Fig. 1).
In spite of significant proof for high species richness among angiosperms considering that the Albian-Cenomanian (1), the angiosperm contribution to canopy cover before the Campanian-Maastrichtian (that is, in the time of the mid-Cretaceous) remains obscure (10, 15). Only a handful of plant assembleras via fossilized woods are well-known from the Turonian of The United States and Canada, and also none of those specimens technique the dimension of the Ferron log (data file S1). The largest of the previously documented mid-Cretaceous woods are P. arizonense logs >0.6 m in diameter from the Cenomanian-Turonian of Arizona (8), and P. alabamense logs >0.9 m in diameter from the Cenomanian-Turonian of Alabama (13, 26). This discovery demonstprices that angiosperm trees approaching 2 m in diameter were part of the canopy by the Turonian nearly 15 Ma earlier than previously believed.
We report new and unintended floral and also faunal events from a severely underrepresented time in the terrestrial geologic record of The United States and Canada. Among these newly reported occurrences are chondrichthyan, testudine, crocodyliform, and also ornithopod stays and fern, conifer, and angiosperm megafossils. This Paraphyllanthoxylon is the earliest documented occurrence of an angiosperm tree more than 1.0 m in kept diameter. Our findings demonstrate that by the Turonian, flowering plants diversified to successfully fill the full variety of heights accessible to land also plants.
We offered traditional survey and also excavation techniques to recuperate vertebprice and plant fossils from the study location. The study horizon is the Ferron Sandstone Member of the Mancos Shale Formation in Utah, which documents fairly brief intervals of eastward fluvio-deltaic deposition right into the then-extensive Western Interior Seameans (21). Plant and also vertebprice fossils were gathered on lands administered by the Bureau of Land also Management under permits UT13-013S and UT13-014E. The fossil log was uncovered in a tidal deposit, indicating some degree of carry from the website of expansion. We offered Agisoft Photosdeserve to (34) to develop 3D models of the log making use of photogrammeattempt. Thin sections of transverse, radial, and tangential planes were created utilizing traditional petrographic techniques (35). Thin sections were examined through light microscopy. The summary of the wood anatomy complies with the International Association of Wood Anatomists guidelines (36). Photos were taken via a Canon Electro-Optical System digital camera, placed onto a Nikon microscope for microscopic imeras. The imeras were processed in Photoshop utilizing just whole-photo manipulations to boost contrast. We compared the specimales via various other Cretaceous angiosperm woods described in the literary works and also through fossil specimens at the Florida Museum of Natural History, consisting of those of P. alabamense Cahoon (13). We evaluated the definition of the size of the specimales by comparing it through various other Cretaceous incidents from roughly the human being for which we could obtain diameter estimates. We augmented the data collection of North Amerihave the right to events presented by Jud et al. (37) via updated diameter approximates, and also we included occurrences from various other continents.
We give thanks to M. Becker (William Paterboy University) for discussion, B. Britt and also R. Sheetz (Brigham Young University) for collections access, the Bureau of Land also Management (J. Reay, S. Fivecoat, R. Hunt-Foster, and S. Foss), area aides S. Lande, M. Yaravitz, D. Boudreau, and also M. Giles, S. M. DeWitt for comments and assistance through numbers, C. Gee, and an anonymous reviewer. Funding: This task was supported by the National Geographic Society’s Committee for Research and also Exploration (provide 9252-13), Stony Brook College, and also Adelphi College. Author contributions: Study style by N.A.J., M.D.D., and also S.A.W. N.A.J. and also M.D.D. drafted the manuscript. Field work-related and arsenal by M.D.D., S.A.W., J.C.M., and K.M.T. Geologic context provided by J.B. Vertebrate descriptions and identifications by M.D.D., S.A.W., and J.C.M. N.A.J. described and identified plant stays. All authors gave last approval for the manuscript. Competing interests: The authors declare that they have no completing interests. Data and materials availability: All information required to evaluate the conclusions in the paper are current in the paper and/or the Supplementary Materials. More information and also results supporting this paper have been uploaded as component of the online electronic Supplementary Material and also will certainly also be obtainable on Morphobank ( Other data concerned this paper might be asked for from the authors.

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Table S1. Comparison of the Cretaceous Paraphyllanthoxylon species and the anatomically equivalent genus Aplectotremas.