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Meso JG, Gianechini F, Gomez KL, Muci L, Baiano MA, Pol D, Kaluza J, Garrido A, Pittman M. Shed teeth from Portezuelo formation at Sierra del Portezuelo reveal a higher diversity of predator theropods during Turonian-Coniacian times in northern Patagonia. BMC Ecol Evol 2024; 24:59. [PMID: 38730384 PMCID: PMC11083846 DOI: 10.1186/s12862-024-02249-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 04/30/2024] [Indexed: 05/12/2024] Open
Abstract
The study of thirty-two shed crowns from the Portezuelo Formation (middle Turonian-late Coniacian) at the Sierra del Portezuelo locality, reveals six distinct tooth morphotypes identified through cladistic, discriminant, and cluster analyses. Two morphotypes were identified as belonging to Megaraptoridae, three to Abelisauridae, one to Abelisauroidea, and one to Alvarezsauridae. Additionally, two of the morphotypes exhibit a combination of dental features typically found in megaraptorid and abelisauridtheropods. These results suggest a greater diversity of theropods in the original ecosystem than previously thought, including the presence of a second morphotype of megaraptorid and alvarezsaurid previously undocumented in this formation. Furthermore, the existence of Morphotype 6 indicates the potential coexistence of medium-sized abelisauroids alongside larger abelisaurids in the same ecosystem. These findings underscore the importance of future expeditions to the Sierra del Portezuelo locality to further our understanding of these previously unknown theropod species.
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Affiliation(s)
- Jorge Gustavo Meso
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
- Instituto de Investigación en Paleobiología y Geología (IIPG), Universidad Nacional de Río Negro (UNRN) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), General Roca, Río Negro, 8332, Argentina.
- Universidad Nacional de Río Negro, Sede Alto Valle/Valle Medio, R8332 General Roca, Estados Unidos 750, Río Negro, Argentina.
| | - Federico Gianechini
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL), Universidad Nacional de San Luis, San Luis, Argentina
| | - Kevin Leonel Gomez
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Instituto de Investigación en Paleobiología y Geología (IIPG), Universidad Nacional de Río Negro (UNRN) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), General Roca, Río Negro, 8332, Argentina
| | - Luciana Muci
- Universidad Nacional de Río Negro, Sede Alto Valle/Valle Medio, R8332 General Roca, Estados Unidos 750, Río Negro, Argentina
| | - Mattia Antonio Baiano
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Universidad Nacional de Río Negro, Sede Alto Valle/Valle Medio, R8332 General Roca, Estados Unidos 750, Río Negro, Argentina
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
- DrNatali S/N, Área Laboratorio E Investigación, Museo Municipal 'Ernesto Bachmann', 8311 Villa El Chocon, Neuquén, Argentina
| | - Diego Pol
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Museo Paleontológico Egidio Feruglio, Trelew, Chubut, Argentina
| | - Jonatan Kaluza
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Fundación de Historia Natural Félix de Azara, Universidad Maimónides. Hidalgo 775, Ciudad Autónoma de Buenos Aires, C1405, Argentina
| | - Alberto Garrido
- Museo Provincial de Ciencias Naturales 'Prof. Dr. Juan A. Olsacher'. Dirección Provincial de Minería, Zapala, Neuquén, Argentina
| | - Michael Pittman
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
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Senter PJ. Restudy of shoulder motion in the theropod dinosaur Mononykus olecranus (Alvarezsauridae). PeerJ 2023; 11:e16605. [PMID: 38077415 PMCID: PMC10704983 DOI: 10.7717/peerj.16605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 11/15/2023] [Indexed: 12/18/2023] Open
Abstract
Background Range of motion in the forelimb of the Upper Cretaceous theropod dinosaur Mononykus olecranus, a member of the family Alvarezsauridae, has previously been investigated. However, the method used to investigate range of motion at the shoulder in M. olecranus did not follow the standardized procedure used in subsequent studies. The latter procedure yields more reliable results, and its standardization provides that its results are directly comparable to the results of similar studies in other species. I therefore reinvestigated the range of motion at the shoulder in M. olecranus, using the latter procedure. Methods Casts of the left scapula and coracoid of M. olecranus were posed on a horizontal surface, supported from beneath with modeling clay, with the medial surface of the scapula facing toward the horizontal surface. A cast of the left humerus was posed at the limits of motion through the transverse and parasagittal planes. Photos of the poses in orthal views were superimposed and used to measure range of motion, which was measured as the angle between lines drawn down the long axis of the humerus in each position. Results Through the transverse plane, the humerus of M. olecranus could be elevated to a subhorizontal position and depressed to a subvertical position. It could move through the parasagittal plane from a subvertical position at full protraction to a position above the horizontal at full retraction. These results correct the previous mischaracterization of shoulder motion in M. olecranus as restricted to a small arc with the arms held in a permanent sprawl. The range of humeral motion in M. olecranus is much greater than that found by the previous method and allowed the animal to tuck its arms in at the sides, in addition to allowing them to sprawl so as to orient the palm downward. The wide range of humeral motion allowed M. olecranus to forage for insects by employing hook-and-pull digging at surfaces with a wider range of orientations than the previous study showed to be possible.
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Affiliation(s)
- Philip J. Senter
- Department of Biological and Forensic Sciences, Fayetteville State University, Fayetteville, North Carolina, United States
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Kubo K, Kobayashi Y, Chinzorig T, Tsogtbaatar K. A new alvarezsaurid dinosaur (Theropoda, Alvarezsauria) from the Upper Cretaceous Baruungoyot Formation of Mongolia provides insights for bird-like sleeping behavior in non-avian dinosaurs. PLoS One 2023; 18:e0293801. [PMID: 37967055 PMCID: PMC10651048 DOI: 10.1371/journal.pone.0293801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 10/19/2023] [Indexed: 11/17/2023] Open
Abstract
Alvarezsauria is a group of early-branching maniraptoran theropods that are distributed globally from the Late Jurassic to the latest Cretaceous. Despite recent increases in the fossil record of this group, the scarcity of complete specimens still restricts interpreting their detailed anatomy, ecology, and evolution. Here, we report a new taxon of derived alvarezsaur, Jaculinykus yaruui gen. et sp. nov., from the Late Cretaceous of Mongolia, which represents a nearly complete and articulated skeleton. Our phylogenetic analysis reveals that Jaculinykus belongs to the sub-clade of Alvarezsauridae, Parvicursorinae, and forms a mononphyletic group with Mononykus and Shuvuuia. Its well-preserved manus has only two fingers, composed of a hypertrophied digit I and greatly reduced digit II, which implies an intermediate condition between the tridactyl manus of Shuvuuia and monodactyl manus of Linhenykus. This highlights a previously unrecognized variation in specialization of alvarezsaurid manus. Notably, the preserved posture of the specimen exhibits a stereotypical avian-like sleeping position seen in the troodontids Mei and Sinornithoides. Evidence of this behavior in the alvarezsaur Jaculinykus suggests that stereotypically avian sleeping postures are a maniraptoran synapomorphy, providing more evidence of bird-like traits being distributed broadly among avian ancestors.
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Affiliation(s)
- Kohta Kubo
- Department of Natural History and Planetary Sciences, Hokkaido University, Kita-ku, Sapporo, Hokkaido, Japan
| | | | - Tsogtbaatar Chinzorig
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States of America
- Institute of Paleontology, Mongolian Academy of Sciences, Ulaanbaatar, Mongolia
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Qin Z, Liao CC, Benton MJ, Rayfield EJ. Functional space analyses reveal the function and evolution of the most bizarre theropod manual unguals. Commun Biol 2023; 6:181. [PMID: 36797463 PMCID: PMC9935540 DOI: 10.1038/s42003-023-04552-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 02/03/2023] [Indexed: 02/18/2023] Open
Abstract
Maniraptoran dinosaurs include the ancestors of birds, and most used their hands for grasping and in flight, but early-branching maniraptorans had extraordinary claws of mysterious function. Alvarezsauroids had short, strong arms and hands with a stout, rock-pick-like, single functional finger. Therizinosaurians had elongate fingers with slender and sickle-like unguals, sometimes over one metre long. Here we develop a comprehensive methodological framework to investigate what the functions of these most bizarre bony claws are and how they formed. Our analysis includes finite element analysis and a newly established functional-space analysis and also involves shape and size effects in an assessment of function and evolution. We find a distinct functional divergence among manual unguals of early-branching maniraptorans, and we identify a complex relationship between their structural strength, morphological specialisations, and size changes. Our analysis reveals that efficient digging capabilities only emerged in late-branching alvarezsauroid forelimbs, rejecting the hypothesis of functional vestigial structures like T. rex. Our results also support the statement that most therizinosaurians were herbivores. However, the bizarre, huge Therizinosaurus had sickle-like unguals of such length that no mechanical function has been identified; we suggest they were decorative and lengthened by peramorphic growth linked to increased body size.
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Affiliation(s)
- Zichuan Qin
- School of Earth Sciences, Life Sciences Building, University of Bristol, Tyndall Avenue, Bristol, BS8 1TQ, UK.
| | - Chun-Chi Liao
- grid.9227.e0000000119573309Key Laboratory for the Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, 100044 China
| | - Michael J. Benton
- grid.5337.20000 0004 1936 7603School of Earth Sciences, Life Sciences Building, University of Bristol, Tyndall Avenue, Bristol, BS8 1TQ UK
| | - Emily J. Rayfield
- grid.5337.20000 0004 1936 7603School of Earth Sciences, Life Sciences Building, University of Bristol, Tyndall Avenue, Bristol, BS8 1TQ UK
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Guinard G. THE FORELIMBS OF ALVAREZSAUROIDEA (DINOSAURIA: THEROPODA): INSIGHT FROM EVOLUTIONARY TERATOLOGY. J Morphol 2022; 283:1257-1272. [PMID: 35915891 DOI: 10.1002/jmor.21500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 07/14/2022] [Accepted: 07/17/2022] [Indexed: 11/09/2022]
Abstract
Alvarezsauroidea (Tetanurae) are non-avian theropod dinosaurs whose forelimb evolution is characterised by overdevelopment of digit I, at the expense of the other two digits, complemented by a drastic forelimb shortening in derived species (Parvicursorinae). These variations are recognised as evolutionary developmental anomalies. Evolutionary teratology hence leads to a double diagnosis with 1) macrodactyly of digit I and microdactyly of digits II and III, plus 2) anterior micromelia. The teratological macrodactyly/microdactyly coupling evolved first. Developmental mechanisms disturbing limb proportion are thought to be convergent with those of other Tetanurae (Tyrannosauridae, Carcharodontosauridae). As for the manual anomalies, both are specific to Alvarezsauroidea (macrodactyly/microdactyly) and inherited (digit loss/reduction). While considering the frame-shift theory, posterior digits develop before the most anterior one. There would therefore be a decrease in the area devoted to digits II (condensation 3) and III (condensation 4), in connection with the Shh signalling pathway, interacting with other molecular players such as the GLI 3 protein and the Hox system. Developmental independence of digit I (condensation 2) would contribute to generate a particular morphology. Macrodactyly would be linked to a variation in Hoxd-13, impacting Gli3 activity, increasing cell proliferation. The loss/reduction of digital ray/phalanges (digits II and III), would be associated to Shh activity, a mechanism inherited from the theropodan ancestry. The macrodactyly/macrodactyly coupling, and then anterior micromelia, fundamentally changed the forelimb mechanical function, compared to the 'classical' grasping structure of basal representatives and other theropods. The distal ossification of the macrodactylian digit has been identified as physiological, implying the use of the structure. However, the debate of a particular 'adaptive' use is pointless since the ecology of an organism is interactively complex, being both at the scale of the individual and dependent on circumstances. Other anatomical features also allow for compensation and a different predation (cursorial hindlimbs). This article is protected by copyright. All rights reserved.
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Qin Z, Zhao Q, Choiniere JN, Clark JM, Benton MJ, Xu X. Growth and miniaturization among alvarezsauroid dinosaurs. Curr Biol 2021; 31:3687-3693.e5. [PMID: 34233160 DOI: 10.1016/j.cub.2021.06.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 04/06/2021] [Accepted: 06/07/2021] [Indexed: 11/28/2022]
Abstract
Sustained miniaturization, here defined as a drop in body size of at least two orders of magnitude from ancestors to descendants, is a widespread and important phenomenon in animals,1-3 but among dinosaurs, miniaturization occurred only rarely, once in the lineage leading to birds and once in the Alvarezsauroidea,1,3-5 one of the most bizarre theropod groups.1,5-7 Miniaturization and powered flight are intimately linked in avialan theropods,3,5,6,8-11 but the causes and patterns of body size reduction are less clear in the non-volant Alvarezsauroidea.1,5,6,12,13 Here, we present results from analyses on a comprehensive dataset, which not only includes new data from early-branching alvarezsauroids but also considers the ontogenetic effect based on histological data. Our analyses show that alvarezsauroid body mass underwent rapid miniaturization from around 110 to 85 mya and that there was a phylogenetic radiation of small-sized alvarezsauroids in the Late Cretaceous. Our analyses also indicate that growth strategies were highly variable among alvarezsauroids, with significant differences among extremely small taxa. The suggested alvarezsauroid miniaturization and associated phylogenetic radiation are coincident with the emergence of ants and termites, and combining previous functional morphological data, our study suggests that alvarezsauroid miniaturization might have been driven by ecological changes during the Cretaceous Terrestrial Revolution, more specifically by a shift to the myrmecophagous ecological niche.
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Affiliation(s)
- Zichuan Qin
- School of Earth Sciences, Life Sciences Building, University of Bristol, Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Qi Zhao
- Key Laboratory for the Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China; CAS Center of Excellence in Life and Paleoenvironment, Beijing 100044, China
| | - Jonah N Choiniere
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - James M Clark
- Department of Biological Sciences, George Washington University, Washington, DC, USA
| | - Michael J Benton
- School of Earth Sciences, Life Sciences Building, University of Bristol, Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Xing Xu
- Key Laboratory for the Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China; CAS Center of Excellence in Life and Paleoenvironment, Beijing 100044, China.
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Hanson M, Hoffman EA, Norell MA, Bhullar BAS. The early origin of a birdlike inner ear and the evolution of dinosaurian movement and vocalization. Science 2021; 372:601-609. [PMID: 33958471 DOI: 10.1126/science.abb4305] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 03/09/2021] [Indexed: 12/27/2022]
Abstract
Reptiles, including birds, exhibit a range of behaviorally relevant adaptations that are reflected in changes to the structure of the inner ear. These adaptations include the capacity for flight and sensitivity to high-frequency sound. We used three-dimensional morphometric analyses of a large sample of extant and extinct reptiles to investigate inner ear correlates of locomotor ability and hearing acuity. Statistical analyses revealed three vestibular morphotypes, best explained by three locomotor categories-quadrupeds, bipeds and simple fliers (including bipedal nonavialan dinosaurs), and high-maneuverability fliers. Troodontids fall with Archaeopteryx among the extant low-maneuverability fliers. Analyses of cochlear shape revealed a single instance of elongation, on the stem of Archosauria. We suggest that this transformation coincided with the origin of both high-pitched juvenile location, alarm, and hatching-synchronization calls and adult responses to them.
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Affiliation(s)
- Michael Hanson
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT, USA.,Peabody Museum of Natural History, Yale University, New Haven, CT, USA
| | - Eva A Hoffman
- Division of Paleontology, American Museum of Natural History, New York, NY, USA
| | - Mark A Norell
- Division of Paleontology, American Museum of Natural History, New York, NY, USA
| | - Bhart-Anjan S Bhullar
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT, USA. .,Peabody Museum of Natural History, Yale University, New Haven, CT, USA
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Griffin CT, Stocker MR, Colleary C, Stefanic CM, Lessner EJ, Riegler M, Formoso K, Koeller K, Nesbitt SJ. Assessing ontogenetic maturity in extinct saurian reptiles. Biol Rev Camb Philos Soc 2020; 96:470-525. [PMID: 33289322 DOI: 10.1111/brv.12666] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 10/09/2020] [Accepted: 10/28/2020] [Indexed: 01/06/2023]
Abstract
Morphology forms the most fundamental level of data in vertebrate palaeontology because it is through interpretations of morphology that taxa are identified, creating the basis for broad evolutionary and palaeobiological hypotheses. Assessing maturity is one of the most basic aspects of morphological interpretation and provides the means to study the evolution of ontogenetic changes, population structure and palaeoecology, life-history strategies, and heterochrony along evolutionary lineages that would otherwise be lost to time. Saurian reptiles (the least-inclusive clade containing Lepidosauria and Archosauria) have remained an incredibly diverse, numerous, and disparate clade through their ~260-million-year history. Because of the great disparity in this group, assessing maturity of saurian reptiles is difficult, fraught with methodological and terminological ambiguity. We compiled a novel database of literature, assembling >900 individual instances of saurian maturity assessment, to examine critically how saurian maturity has been diagnosed. We review the often inexact and inconsistent terminology used in saurian maturity assessment (e.g. 'juvenile', 'mature') and provide routes for better clarity and cross-study coherence. We describe the various methods that have been used to assess maturity in every major saurian group, integrating data from both extant and extinct taxa to give a full account of the current state of the field and providing method-specific pitfalls, best practices, and fruitful directions for future research. We recommend that a new standard subsection, 'Ontogenetic Assessment', be added to the Systematic Palaeontology portions of descriptive studies to provide explicit ontogenetic diagnoses with clear criteria. Because the utility of different ontogenetic criteria is highly subclade dependent among saurians, even for widely used methods (e.g. neurocentral suture fusion), we recommend that phylogenetic context, preferably in the form of a phylogenetic bracket, be used to justify the use of a maturity assessment method. Different methods should be used in conjunction as independent lines of evidence when assessing maturity, instead of an ontogenetic diagnosis resting entirely on a single criterion, which is common in the literature. Critically, there is a need for data from extant taxa with well-represented growth series to be integrated with the fossil record to ground maturity assessments of extinct taxa in well-constrained, empirically tested methods.
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Affiliation(s)
- Christopher T Griffin
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
| | - Michelle R Stocker
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
| | - Caitlin Colleary
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Vertebrate Paleontology, Cleveland Museum of Natural History, 1 Wade Oval Drive, Cleveland, OH, 44106, U.S.A
| | - Candice M Stefanic
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Anatomical Sciences, Stony Brook University, 100 Nicolls Road, Stony Brook, NY, 11794, U.S.A
| | - Emily J Lessner
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Pathology and Anatomical Sciences, University of Missouri, 1 Hospital Drive, Columbia, MO, 65212, U.S.A
| | - Mitchell Riegler
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Geological Sciences, University of Florida, 241 Williamson Hall, Gainesville, FL, 32611, U.S.A
| | - Kiersten Formoso
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Earth Sciences, University of Southern California, 3651 Trousdale Pkwy, Los Angeles, CA, 90089, U.S.A
- Dinosaur Institute, Natural History Museum of Los Angeles County, 900 W Exposition Boulevard, Los Angeles, CA, 90007, U.S.A
| | - Krista Koeller
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Biology, University of Florida, 220 Bartram Hall, Gainesville, FL, 32611, U.S.A
| | - Sterling J Nesbitt
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
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