New data towards the development of a comprehensive taphonomic framework for the Late Jurassic Cleveland-Lloyd Dinosaur Quarry, Central Utah

The Cleveland-Lloyd Dinosaur Quarry (CLDQ) is the densest deposit of Jurassic theropod dinosaurs discovered to date. Unlike typical Jurassic bone deposits, it is dominated by the presence ofAllosaurus fragilis. Since excavation began in the 1920s, numerous hypotheses have been put forward to explain the taphonomy of CLDQ, including a predator trap, a drought assemblage, and a poison spring. In an effort to reconcile the various interpretations of the quarry and reach a consensus on the depositional history of CLDQ, new data is required to develop a robust taphonomic framework congruent with all available data. Here we present two new data sets that aid in the development of such a robust taphonomic framework for CLDQ. First, x-ray fluorescence of CLDQ sediments indicate elevated barite and sulfide minerals relative to other sediments from the Morrison Formation in the region, suggesting an ephemeral environment dominated by periods of hypereutrophic conditions during bone accumulation. Second, the degree of abrasion and hydraulic equivalency of small bone fragments dispersed throughout the matrix were analyzed from CLDQ. Results of these analyses suggest that bone fragments are autochthonous or parautochthonous and are derived from bones deposited in the assemblage rather than transported. The variability in abrasion exhibited by the fragments is most parsimoniously explained by local periodic re-working and re-deposition during seasonal fluctuations throughout the duration of the quarry assemblage. Collectively, these data support previous interpretations that the CLDQ represents an attritional assemblage in a poorly-drained overbank deposit where vertebrate remains were introduced post-mortem to an ephemeral pond during flood conditions. Furthermore, while the elevated heavy metals detected at the Cleveland-Lloyd Dinosaur Quarry are not likely the primary driver for the accumulation of carcasses, they are likely the result of multiple sources; some metals may be derived from post-depositional and diagenetic processes, and others are potentially produced from an abundance of decomposing vertebrate carcasses. These new data help to support the inferred depositional environment of the quarry as an ephemeral pond, and represent a significant step in understanding the taphonomy of the bonebed and Late Jurassic paleoecology in this region.

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New data towards the development of a comprehensive taphonomic framework for the Cleveland-Lloyd Dinosaur Quarry

10.7287/peerj.preprints.2600 ◽

2016 ◽

Author(s):

Joseph E Peterson ◽

Jonathan P Warnock ◽

Shawn L Eberhart ◽

Steven R Clawson ◽

Christopher R Noto

Keyword(s):

Data Sets ◽

Morrison Formation ◽

Depositional History ◽

Theropod Dinosaurs ◽

The Matrix ◽

Significant Step ◽

Primary Driver ◽

History Of ◽

Bone Fragments ◽

Small Bone

The Cleveland-Lloyd Dinosaur Quarry (CLDQ) is the densest deposit of Jurassic theropod dinosaurs discovered to date. Unlike typical Jurassic bone deposits, it is dominated by the presence of Allosaurus fragilis. Since excavation began in the 1920’s numerous hypotheses have been put forward to explain the taphonomy of CLDQ, including a predator trap, a drought assemblage, and a poison spring. In an effort to reconcile the various interpretations of the quarry and reach a consensus on the depositional history of CLDQ, new data is required to develop a robust taphonomic framework congruent with all available data. Here we present two new data sets which aid in the development of such a robust taphonomic framework for CLDQ. First, x-ray fluorescence of CLDQ sediments indicate elevated barite and sulfide minerals relative to other sediments from the Morrison Formation, suggesting an ephemeral environment dominated by periods of hypereutrophic conditions during bone accumulation. Second, the degree of weathering and hydraulic equivalency of small bone fragments dispersed throughout the matrix were analyzed from CLDQ. Results of these analyses suggest that bone fragments are autochthonous or parautochthonous and are derived from bones deposited in the assemblage. The variability in abrasion exhibited by the fragments is most parsimoniously explained by periodic reworking and redeposition during seasonal fluctuations throughout the duration of the quarry assemblage. Collectively, these data support some previous interpretations that the CLDQ represents an attritional assemblage in a poorly-drained overbank deposit where vertebrate remains were introduced post-mortem to an ephemeral pond during flood conditions. Furthermore, elevated heavy metals and rare earth elements detected at the quarry are likely a diagenetic signal, potentially produced in part from an abundance of vertebrate remains, and not the primary driver for the accumulation of carcasses. These new data help to explain the specific depositional environment of the quarry, and represent a significant step in understanding the taphonomy of the bone bed and late Jurassic paleoecology.

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New data towards the development of a comprehensive taphonomic framework for the Cleveland-Lloyd Dinosaur Quarry

10.7287/peerj.preprints.2600v1 ◽

2016 ◽

Author(s):

Joseph E Peterson ◽

Jonathan P Warnock ◽

Shawn L Eberhart ◽

Steven R Clawson ◽

Christopher R Noto

Keyword(s):

Data Sets ◽

Morrison Formation ◽

Depositional History ◽

Theropod Dinosaurs ◽

The Matrix ◽

Significant Step ◽

Primary Driver ◽

History Of ◽

Bone Fragments ◽

Small Bone

The Cleveland-Lloyd Dinosaur Quarry (CLDQ) is the densest deposit of Jurassic theropod dinosaurs discovered to date. Unlike typical Jurassic bone deposits, it is dominated by the presence of Allosaurus fragilis. Since excavation began in the 1920’s numerous hypotheses have been put forward to explain the taphonomy of CLDQ, including a predator trap, a drought assemblage, and a poison spring. In an effort to reconcile the various interpretations of the quarry and reach a consensus on the depositional history of CLDQ, new data is required to develop a robust taphonomic framework congruent with all available data. Here we present two new data sets which aid in the development of such a robust taphonomic framework for CLDQ. First, x-ray fluorescence of CLDQ sediments indicate elevated barite and sulfide minerals relative to other sediments from the Morrison Formation, suggesting an ephemeral environment dominated by periods of hypereutrophic conditions during bone accumulation. Second, the degree of weathering and hydraulic equivalency of small bone fragments dispersed throughout the matrix were analyzed from CLDQ. Results of these analyses suggest that bone fragments are autochthonous or parautochthonous and are derived from bones deposited in the assemblage. The variability in abrasion exhibited by the fragments is most parsimoniously explained by periodic reworking and redeposition during seasonal fluctuations throughout the duration of the quarry assemblage. Collectively, these data support some previous interpretations that the CLDQ represents an attritional assemblage in a poorly-drained overbank deposit where vertebrate remains were introduced post-mortem to an ephemeral pond during flood conditions. Furthermore, elevated heavy metals and rare earth elements detected at the quarry are likely a diagenetic signal, potentially produced in part from an abundance of vertebrate remains, and not the primary driver for the accumulation of carcasses. These new data help to explain the specific depositional environment of the quarry, and represent a significant step in understanding the taphonomy of the bone bed and late Jurassic paleoecology.

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BONE FRAGMENTS FROM THE MATRIX OF THE CLEVELAND-LLOYD DINOSAUR QUARRY (UPPER JURASSIC MORRISON FORMATION) AND THEIR BEARING ON DEPOSITIONAL RECONSTRUCTION

10.1130/abs/2016nc-274876 ◽

2016 ◽

Author(s):

Joseph E. Peterson ◽

◽

Shawn Eberhart ◽

Jonathan P. Warnock ◽

Steven R. Clawson ◽

...

Keyword(s):

Upper Jurassic ◽

Morrison Formation ◽

The Matrix ◽

Bone Fragments

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Small pterosaurs and dinosaurs from the Uncompahgre fauna (Brushy Basin Member, Morrison Formation: ?Tithonian), Late Jurassic, western Colorado

Journal of Paleontology ◽

10.1017/s0022336000019533 ◽

1989 ◽

Vol 63 (3) ◽

pp. 364-373 ◽

Cited By ~ 29

Author(s):

James A. Jensen ◽

Kevin Padian

Keyword(s):

Distal Radius ◽

Late Jurassic ◽

Proximal Tibia ◽

Morrison Formation ◽

Additional Material ◽

Western Colorado ◽

Single Form ◽

The Matrix

Small vertebrates were recovered from the matrix encasing specimens of giant sauropod dinosaurs (Supersaurus, Ultrasaurus, Dystylosaurus) collected from the “Dry Mesa” Quarry (Brushy Basin Member, Morrison Formation, western Colorado). Most of the remains appear to pertain to a single form of pterodactyloid pterosaur, Mesadactylus ornithosphyos, n. gen. and sp., the holotype of which is a synsacrum. A bone end from this quarry, first identified as an avian proximal tibia and named Palaeopteryx thomsoni, is reidentified as the distal radius of a small deinonychosaur or bird. A small femur of a small deinonychosaur or bird and additional material of other small vertebrates from this quarry are figured and described.

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Notes on the cheek region of the Late Jurassic theropod dinosaur Allosaurus

PeerJ ◽

10.7717/peerj.8493 ◽

2020 ◽

Vol 8 ◽

pp. e8493

Author(s):

Serjoscha W. Evers ◽

Christian Foth ◽

Oliver W.M. Rauhut

Keyword(s):

North America ◽

19Th Century ◽

Late Jurassic ◽

Morrison Formation ◽

Late 19Th Century ◽

Theropod Dinosaur ◽

European Species ◽

Theropod Dinosaurs ◽

The Common ◽

Iconic Status

Allosaurus, from the Late Jurassic of North America and Europe, is a model taxon for Jurassic basal tetanuran theropod dinosaurs. It has achieved an almost iconic status due to its early discovery in the late, 19th century, and due to the abundance of material from the Morrison Formation of the western U.S.A., making Allosaurus one of the best-known theropod taxa. Despite this, various aspects of the cranial anatomy of Allosaurus are surprisingly poorly understood. Here, we discuss the osteology of the cheek region, comprised by the jugal, maxilla, and lacrimal. This region of the skull is of importance for Allosaurus taxonomy and phylogeny, particularly because Allosaurus has traditionally been reconstructed with an unusual cheek configuration, and because the European species Allosaurus europaeus has been said to be different from North American material in the configuration of these bones. Based on re-examination of articulated and disarticulated material from a number of repositories, we show that the jugal participates in the antorbital fenestra, contradicting the common interpretation. The jugal laterally overlies the lacrimal, and forms an extended antorbital fossa with this bone. Furthermore, we document previously unrecorded pneumatic features of the jugal of Allosaurus.

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The Mesozoic Biogeographic History of Gondwanan Terrestrial Vertebrates: Insights from Madagascar's Fossil Record

Annual Review of Earth and Planetary Sciences ◽

10.1146/annurev-earth-053018-060051 ◽

2019 ◽

Vol 47 (1) ◽

pp. 519-553 ◽

Cited By ~ 11

Author(s):

David W. Krause ◽

Joseph J.W. Sertich ◽

Patrick M. O'Connor ◽

Kristina Curry Rogers ◽

Raymond R. Rogers

Keyword(s):

Late Cretaceous ◽

Fossil Record ◽

Late Jurassic ◽

Indian Subcontinent ◽

Terrestrial Vertebrates ◽

Faunal Assemblages ◽

Theropod Dinosaurs ◽

Biogeographic History ◽

History Of ◽

The Caribbean

The Mesozoic plate tectonic and paleogeographic history of Gondwana had a profound effect on the distribution of terrestrial vertebrates. As the supercontinent fragmented into a series of large landmasses (South America, Africa-Arabia, Antarctica, Australia, New Zealand, the Indian subcontinent, and Madagascar), particularly during the Late Jurassic and Cretaceous, its terrestrial vertebrates became progressively isolated, evolving into unique faunal assemblages. We focus on four clades that, during the Mesozoic, had relatively low ability for dispersal across oceanic barriers—crocodyliforms, sauropod dinosaurs, nonavian theropod dinosaurs, and mammals. Their distributions reveal patterns that are critically important in evaluating various biogeographic hypotheses, several of which have been informed by recent discoveries from the Late Cretaceous of Madagascar. We also examine the effects of lingering, intermittent connections, or reconnections, of Gondwanan landmasses with Laurasia (through the Caribbean, Mediterranean, and Himalayan regions) on the distributions of different clades. ▪ This article reviews the biogeographic history of terrestrial vertebrates from the Mesozoic of the southern supercontinent Gondwana. ▪ Relatively large, terrestrial animals—including crocodyliforms, sauropod and nonavian theropod dinosaurs, and mammals—are the focus of this review. ▪ Most patterns related to vicariance occurred during the Late Jurassic and Cretaceous, the intervals of most active Gondwanan fragmentation. ▪ Recent discoveries of vertebrates from the Late Cretaceous of Madagascar have played a key role in formulating and testing various biogeographic hypotheses.

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Tertiary Bird History: Notes and Comments

Short Courses in Paleontology ◽

10.1017/s2475263000001318 ◽

1994 ◽

Vol 7 ◽

pp. 179-189

Author(s):

Alan Feduccia

Keyword(s):

Late Jurassic ◽

Controversial Issue ◽

Avian Flight ◽

The Past ◽

Theropod Dinosaurs ◽

Modern Bird ◽

History Of ◽

Tertiary Period

No area of paleontology has changed more in recent years than the history of birds, both during the Mesozoic Era and the Tertiary Period. The most controversial issue in the study of birds for several decades has been their origin, and the origin of avian flight and feathers, and clearly too much emphasis has been placed on the earliest known bird, the late Jurassic Archaeopteyx, an arboreal form that was already well on its way to becoming a modern bird (Feduccia, 1993a). Over the past two decades this urvögel has mistakenly been characterized as an earth-bound, feathered theropod, and a number of rather bizarre scenarios have been envisioned to account for the origin of flight and feathers in birds. However, the debate has centered on two main themes. Were birds derived directly from small, bipedal theropod dinosaurs (Ostrom, 1991), and therefore evolved via the scenario of the cursorial (ground-up) theory (Ostrom, 1986); or were they derived earlier in time from small, arboreal “thecodonts” or basal archosaurs, and therefore evolved via the scenario of the arboreal (trees-down) theory (Bock, 1986; Martin, 1991; Feduccia and Wild, 1993).

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