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Chiarenza AA, Cantalapiedra JL, Jones LA, Gamboa S, Galván S, Farnsworth AJ, Valdes PJ, Sotelo G, Varela S. Early Jurassic origin of avian endothermy and thermophysiological diversity in dinosaurs. Curr Biol 2024:S0960-9822(24)00525-6. [PMID: 38754424 DOI: 10.1016/j.cub.2024.04.051] [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: 02/07/2024] [Revised: 03/25/2024] [Accepted: 04/22/2024] [Indexed: 05/18/2024]
Abstract
A fundamental question in dinosaur evolution is how they adapted to long-term climatic shifts during the Mesozoic and when they developed environmentally independent, avian-style acclimatization, becoming endothermic.1,2 The ability of warm-blooded dinosaurs to flourish in harsher environments, including cold, high-latitude regions,3,4 raises intriguing questions about the origins of key innovations shared with modern birds,5,6 indicating that the development of homeothermy (keeping constant body temperature) and endothermy (generating body heat) played a crucial role in their ecological diversification.7 Despite substantial evidence across scientific disciplines (anatomy,8 reproduction,9 energetics,10 biomechanics,10 osteohistology,11 palaeobiogeography,12 geochemistry,13,14 and soft tissues15,16,17), a consensus on dinosaur thermophysiology remains elusive.1,12,15,17,18,19 Differential thermophysiological strategies among terrestrial tetrapods allow endotherms (birds and mammals) to expand their latitudinal range (from the tropics to polar regions), owing to their reduced reliance on environmental temperature.20 By contrast, most reptilian lineages (squamates, turtles, and crocodilians) and amphibians are predominantly constrained by temperature in regions closer to the tropics.21 Determining when this macroecological pattern emerged in the avian lineage relies heavily on identifying the origin of these key physiological traits. Combining fossils with macroevolutionary and palaeoclimatic models, we unveil distinct evolutionary pathways in the main dinosaur lineages: ornithischians and theropods diversified across broader climatic landscapes, trending toward cooler niches. An Early Jurassic shift to colder climates in Theropoda suggests an early adoption of endothermy. Conversely, sauropodomorphs exhibited prolonged climatic conservatism associated with higher thermal conditions, emphasizing temperature, rather than plant productivity, as the primary driver of this pattern, suggesting poikilothermy with a stronger dependence on higher temperatures in sauropods.
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Affiliation(s)
- Alfio Alessandro Chiarenza
- Centro de Investigación Mariña, Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain; Department of Earth Sciences, University College London, Gower Place, London WC1E 6BS, UK.
| | - Juan L Cantalapiedra
- Departamento de Paleobiología, Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2, 28006 Madrid, Spain; GloCEE Global Change Ecology and Evolution Research Group, Departamento de Ciencias de la Vida, Universidad de Alcalá, 28801 Alcalá de Henares, Spain; Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invdralidenstraße 43, 10115 Berlin, Germany
| | - Lewis A Jones
- Centro de Investigación Mariña, Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain
| | - Sara Gamboa
- Centro de Investigación Mariña, Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain; Universidad Complutense de Madrid, Av. Séneca 2, 28040 Madrid, Spain
| | - Sofía Galván
- Centro de Investigación Mariña, Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain
| | - Alexander J Farnsworth
- School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK; State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Paul J Valdes
- School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK; State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Graciela Sotelo
- Centro de Investigación Mariña, Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain
| | - Sara Varela
- Centro de Investigación Mariña, Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain
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2
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Lacerda MBS, Bittencourt JS, Hutchinson JR. Reconstruction of the pelvic girdle and hindlimb musculature of the early tetanurans Piatnitzkysauridae (Theropoda, Megalosauroidea). J Anat 2024; 244:557-593. [PMID: 38037880 PMCID: PMC10941590 DOI: 10.1111/joa.13983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 12/02/2023] Open
Abstract
Piatnitzkysauridae were Jurassic theropods that represented the earliest diverging branch of Megalosauroidea, being one of the earliest lineages to have evolved moderate body size. This clade's typical body size and some unusual anatomical features raise questions about locomotor function and specializations to aid in body support; and other palaeobiological issues. Biomechanical models and simulations can illuminate how extinct animals may have moved, but require anatomical data as inputs. With a phylogenetic context, osteological evidence, and neontological data on anatomy, it is possible to infer the musculature of extinct taxa. Here, we reconstructed the hindlimb musculature of Piatnitzkysauridae (Condorraptor, Marshosaurus, and Piatnitzkysaurus). We chose this clade for future usage in biomechanics, for comparisons with myological reconstructions of other theropods, and for the resulting evolutionary implications of our reconstructions; differential preservation affects these inferences, so we discuss these issues as well. We considered 32 muscles in total: for Piatnitzkysaurus, the attachments of 29 muscles could be inferred based on the osteological correlates; meanwhile, in Condorraptor and Marshosaurus, we respectively inferred 21 and 12 muscles. We found great anatomical similarity within Piatnitzkysauridae, but differences such as the origin of M. ambiens and size of M. caudofemoralis brevis are present. Similarities were evident with Aves, such as the division of the M. iliofemoralis externus and M. iliotrochantericus caudalis and a broad depression for the M. gastrocnemius pars medialis origin on the cnemial crest. Nevertheless, we infer plesiomorphic features such as the origins of M. puboischiofemoralis internus 1 around the "cuppedicus" fossa and M. ischiotrochantericus medially on the ischium. As the first attempt to reconstruct muscles in early tetanurans, our study allows a more complete understanding of myological evolution in theropod pelvic appendages.
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Affiliation(s)
- Mauro B. S. Lacerda
- Structure and Motion Laboratory, Department of Comparative Biomedical SciencesThe Royal Veterinary CollegeHatfieldUK
- Pós‐Graduação em ZoologiaInstituto de Ciências Biológicas, Universidade Federal de Minas GeraisBelo HorizonteBrazil
| | - Jonathas S. Bittencourt
- Departamento de GeologiaInstituto de Geociências, Universidade Federal de Minas GeraisBelo HorizonteBrazil
| | - John R. Hutchinson
- Structure and Motion Laboratory, Department of Comparative Biomedical SciencesThe Royal Veterinary CollegeHatfieldUK
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3
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Desojo JB, Rauhut OWM. Reassessment of the enigmatic "Prestosuchus" loricatus (Archosauria: Pseudosuchia) from the Middle-Late Triassic of southern Brazil. Anat Rec (Hoboken) 2024; 307:974-1000. [PMID: 38344898 DOI: 10.1002/ar.25401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 01/16/2024] [Accepted: 01/19/2024] [Indexed: 03/16/2024]
Abstract
Our knowledge of the diversity and evolution of South American Triassic pseudosuchians has greatly improved in the past 15 years, due to new discoveries, but also to the revision of several historically important specimens. One of the earliest descriptions of pseudosuchians from the Triassic of Brazil stems from the classic work of Huene from the first half of the 20th century, who described several species, including such influential taxa as Rauisuchus tiradentes or Prestosuchus chiniquensis, which have recently been reviewed. The more poorly known proposed second species of Prestosuchus, P. loricatus, is the focus of the present work. The original material included some elements of the axial skeleton (cervical and caudal vertebrae, ribs, osteoderms) and the hindlimb (ischia, calcaneum, metatarsus), collected from the Dinodontosaurus Assemblage Zone of the Chiniquá area, west of São Pedro do Sul. "Prestosuchus" loricatus shows numerous differences to P. chiniquensis, including the shape of cervical neural spines, presence of epipophyses on the cervical vertebrae, presence of a pit in the iliac articulation of the ischium, lack of longitudinal furrows in the dorsolateral surface of the ischial shafts, the more slender calcaneal tuber and a less pronounced ventral pit in the calcaneum, and is thus referred to a new genus, Schultzsuchus gen. nov. Phylogenetic analysis indicates an early branching position within Poposauroidea for Schultzsuchus, making it the oldest known member of this clade in South America.
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Affiliation(s)
- Julia B Desojo
- División Paleontología Vertebrados, Museo de La Plata, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Buenos Aires, Argentina
- GeoBioCenter, Ludwig-Maximilians-Universität Munich, Munich, Germany
- SNSB - Bayerische Staatssammlung für Paläontologie und Geologie, Munich, Germany
| | - Oliver W M Rauhut
- SNSB - Bayerische Staatssammlung für Paläontologie und Geologie, Munich, Germany
- Sektion Paläontologie, Department für Geo- und Umweltwissenschaften, Ludwig-Maximilians-Universität Munich, Munich, Germany
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4
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Xu L, Wang M, Chen R, Dong L, Lin M, Xu X, Tang J, You H, Zhou G, Wang L, He W, Li Y, Zhang C, Zhou Z. A new avialan theropod from an emerging Jurassic terrestrial fauna. Nature 2023; 621:336-343. [PMID: 37674081 DOI: 10.1038/s41586-023-06513-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 08/02/2023] [Indexed: 09/08/2023]
Abstract
Birds are descended from non-avialan theropod dinosaurs of the Late Jurassic period, but the earliest phase of this evolutionary process remains unclear owing to the exceedingly sparse and spatio-temporally restricted fossil record1-5. Information about the early-diverging species along the avialan line is crucial to understand the evolution of the characteristic bird bauplan, and to reconcile phylogenetic controversies over the origin of birds3,4. Here we describe one of the stratigraphically youngest and geographically southernmost Jurassic avialans, Fujianvenator prodigiosus gen. et sp. nov., from the Tithonian age of China. This specimen exhibits an unusual set of morphological features that are shared with other stem avialans, troodontids and dromaeosaurids, showing the effects of evolutionary mosaicism in deep avialan phylogeny. F. prodigiosus is distinct from all other Mesozoic avialan and non-avialan theropods in having a particularly elongated hindlimb, suggestive of a terrestrial or wading lifestyle-in contrast with other early avialans, which exhibit morphological adaptations to arboreal or aerial environments. During our fieldwork in Zhenghe where F. prodigiosus was found, we discovered a diverse assemblage of vertebrates dominated by aquatic and semi-aquatic species, including teleosts, testudines and choristoderes. Using in situ radioisotopic dating and stratigraphic surveys, we were able to date the fossil-containing horizons in this locality-which we name the Zhenghe Fauna-to 148-150 million years ago. The diversity of the Zhenghe Fauna and its precise chronological framework will provide key insights into terrestrial ecosystems of the Late Jurassic.
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Affiliation(s)
- Liming Xu
- Fujian Institute of Geological Survey, Fuzhou, China
| | - Min Wang
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China.
| | - Runsheng Chen
- Fujian Institute of Geological Survey, Fuzhou, China
| | - Liping Dong
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
| | - Min Lin
- Fujian Institute of Geological Survey, Fuzhou, China
| | - Xing Xu
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
- Centre for Vertebrate Evolutionary Biology, Yunnan University, Kunming, China
- Paleontological Museum of Liaoning, Shenyang Normal University, Shenyang, China
| | - Jianrong Tang
- Fujian Institute of Geological Survey, Fuzhou, China
| | - Hailu You
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
| | - Guowu Zhou
- Fujian Institute of Geological Survey, Fuzhou, China
| | - Linchang Wang
- Fujian Institute of Geological Survey, Fuzhou, China
| | - Wenxing He
- Fujian Institute of Geological Survey, Fuzhou, China
| | - Yujuan Li
- Fujian Institute of Geological Survey, Fuzhou, China
| | - Chi Zhang
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
| | - Zhonghe Zhou
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
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5
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Wang M, Zhou Z. Low morphological disparity and decelerated rate of limb size evolution close to the origin of birds. Nat Ecol Evol 2023; 7:1257-1266. [PMID: 37277496 DOI: 10.1038/s41559-023-02091-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 05/09/2023] [Indexed: 06/07/2023]
Abstract
The origin of birds from theropod dinosaurs involves many changes in musculoskeletal anatomy and epidermal structures, including multiple instances of convergence and homology-related traits that contribute to the refinement of flight capability. Changes in limb sizes and proportions are important for locomotion (for example, the forelimb for bird flight); thus, understanding these patterns is central to investigating the transition from terrestrial to volant theropods. Here we analyse the patterns of morphological disparity and the evolutionary rate of appendicular limbs along avialan stem lineages using phylogenetic comparative approaches. Contrary to the traditional wisdom that an evolutionary innovation like flight would promote and accelerate evolvability, our results show a shift to low disparity and decelerated rate near the origin of avialans that is largely ascribed to the evolutionarily constrained forelimb. These results suggest that natural selection shaped patterns of limb evolution close to the origin of avialans in a way that may reflect the winged forelimb 'blueprint' associated with powered flight.
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Affiliation(s)
- Min Wang
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China.
| | - Zhonghe Zhou
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
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6
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Lacerda MBS, Bittencourt JS, Hutchinson JR. Macroevolutionary patterns in the pelvis, stylopodium and zeugopodium of megalosauroid theropod dinosaurs and their importance for locomotor function. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230481. [PMID: 37593714 PMCID: PMC10427828 DOI: 10.1098/rsos.230481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 07/27/2023] [Indexed: 08/19/2023]
Abstract
During the Mesozoic, non-avian theropods represented one of the most successful clades globally distributed, with a wide diversity of forms. An example is the clade Megalosauroidea, which included medium- to large-bodied forms. Here, we analyse the macroevolution of the locomotor system in early Theropoda, emphasizing the Megalosauroidea. We scored the Spinosaurus neotype in a published taxon-character matrix and described the associated modifications in character states, mapping them onto a phylogeny and using these to study disparity. In the evolution of Megalosauroidea, there was the mosaic emergence of a low swollen ridge; enlargement of the posterior brevis fossa and emergence of a posterodorsal process on the ilium in some megalosauroids; emergence of a femoral head oriented anteromedially and medially angled, and appearance of posterolaterally oriented medial femoral condyles in spinosaurids. The greatest morphological disparity is in the ilium of megalosaurids; the ischium seems to have a high degree of homoplasy; there is a clear distinction in the femoral morphospace regarding megalosauroids and other theropods; piatnitzkysaurids show considerable disparity of zeugopodial characters. These reconstructions of osteological evolution form a stronger basis on which other studies could build, such as mapping of pelvic/appendicular musculature and/or correlating skeletal traits with changes in locomotor function.
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Affiliation(s)
- Mauro B. S. Lacerda
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hatfield AL9 7TA, UK
- Pós-Graduação em Zoologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil
| | - Jonathas S. Bittencourt
- Departamento de Geologia, Instituto de Geociências, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - John R. Hutchinson
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hatfield AL9 7TA, UK
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7
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Barker CT, Naish D, Gostling NJ. Isolated tooth reveals hidden spinosaurid dinosaur diversity in the British Wealden Supergroup (Lower Cretaceous). PeerJ 2023; 11:e15453. [PMID: 37273543 PMCID: PMC10239232 DOI: 10.7717/peerj.15453] [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: 03/01/2023] [Accepted: 05/03/2023] [Indexed: 06/06/2023] Open
Abstract
Isolated spinosaurid teeth are relatively well represented in the Lower Cretaceous Wealden Supergroup of southern England, UK. Until recently it was assumed that these teeth were referable to Baryonyx, the type species (B. walkeri) and specimen of which is from the Barremian Upper Weald Clay Formation of Surrey. British spinosaurid teeth are known from formations that span much of the c. 25 Ma depositional history of the Wealden Supergroup, and recent works suggest that British spinosaurids were more taxonomically diverse than previously thought. On the basis of both arguments, it is appropriate to doubt the hypothesis that isolated teeth from outside the Upper Weald Clay Formation are referable to Baryonyx. Here, we use phylogenetic, discriminant and cluster analyses to test whether an isolated spinosaurid tooth (HASMG G369a, consisting of a crown and part of the root) from a non-Weald Clay Formation unit can be referred to Baryonyx. HASMG G369a was recovered from an uncertain Lower Cretaceous locality in East Sussex but is probably from a Valanginian exposure of the Hastings Group and among the oldest spinosaurid material known from the UK. Spinosaurid affinities are both quantitatively and qualitatively supported, and HASMG G369a does not associate with Baryonyx in any analysis. This supports recent reinterpretations of the diversity of spinosaurid in the Early Cretaceous of Britain, which appears to have been populated by multiple spinosaurid lineages in a manner comparable to coeval Iberian deposits. This work also reviews the British and global records of early spinosaurids (known mainly from dental specimens), and revisits evidence for post-Cenomanian spinosaurid persistence.
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Affiliation(s)
- Chris T. Barker
- Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, United Kingdom
| | - Darren Naish
- School of Biological Sciences, Faculty of Environment and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Neil J. Gostling
- Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
- School of Biological Sciences, Faculty of Environment and Life Sciences, University of Southampton, Southampton, United Kingdom
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8
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D'Emic MD, O'Connor PM, Sombathy RS, Cerda I, Pascucci TR, Varricchio D, Pol D, Dave A, Coria RA, Curry Rogers KA. Developmental strategies underlying gigantism and miniaturization in non-avialan theropod dinosaurs. Science 2023; 379:811-814. [PMID: 36821658 DOI: 10.1126/science.adc8714] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
In amniotes, the predominant developmental strategy underlying body size evolution is thought to be adjustments to the rate of growth rather than its duration. However, most theoretical and experimental studies supporting this axiom focus on pairwise comparisons and/or lack an explicit phylogenetic framework. We present the first large-scale phylogenetic comparative analysis examining developmental strategies underlying the evolution of body size, focusing on non-avialan theropod dinosaurs. We reconstruct ancestral states of growth rate and body mass in a taxonomically rich dataset, finding that contrary to expectations, changes in the rate and duration of growth played nearly equal roles in the evolution of the vast body size disparity present in non-avialan theropods-and perhaps that of amniotes in general.
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Affiliation(s)
- Michael D D'Emic
- Department of Biology, Adelphi University, Garden City, NY, USA
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, USA
| | - Patrick M O'Connor
- Department of Biomedical Sciences, Ohio University Heritage College of Osteopathic Medicine, Athens, OH, USA
- Ohio Center for Ecological and Evolutionary Studies, Ohio University, Athens, OH, USA
| | - Riley S Sombathy
- Department of Biology, Adelphi University, Garden City, NY, USA
- Ohio Center for Ecological and Evolutionary Studies, Ohio University, Athens, OH, USA
- Department of Biological Sciences, Ohio University, Athens, OH, USA
| | - Ignacio Cerda
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, República Argentina
- Instituto de Investigación en Paleobiología y Geología, Universidad Nacional de Río Negro, Museo Carlos Ameghino, Cipolletti, Río Negro, Argentina
| | | | - David Varricchio
- Department of Earth Sciences, Montana State University, Bozeman, MT, USA
| | - Diego Pol
- CONICET-Museo Paleontológico Egidio Feruglio, Trelew, Chubut, Argentina
| | - Anjali Dave
- Department of Biology, Adelphi University, Garden City, NY, USA
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9
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Barker CT, Naish D, Trend J, Michels LV, Witmer L, Ridgley R, Rankin K, Clarkin CE, Schneider P, Gostling NJ. Modified skulls but conservative brains? The palaeoneurology and endocranial anatomy of baryonychine dinosaurs (Theropoda: Spinosauridae). J Anat 2023; 242:1124-1145. [PMID: 36781174 PMCID: PMC10184548 DOI: 10.1111/joa.13837] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/17/2023] [Accepted: 01/17/2023] [Indexed: 02/15/2023] Open
Abstract
The digital reconstruction of neurocranial endocasts has elucidated the gross brain structure and potential ecological attributes of many fossil taxa, including Irritator, a spinosaurine spinosaurid from the "mid" Cretaceous (Aptian) of Brazil. With unexceptional hearing capabilities, this taxon was inferred to integrate rapid and controlled pitch-down movements of the head that perhaps aided in the predation of small and agile prey such as fish. However, the neuroanatomy of baryonychine spinosaurids remains to be described, and potentially informs on the condition of early spinosaurids. Using micro-computed tomographic scanning (μCT), we reconstruct the braincase endocasts of Baryonyx walkeri and Ceratosuchops inferodios from the Wealden Supergroup (Lower Cretaceous) of England. We show that the gross endocranial morphology is similar to other non-maniraptoriform theropods, and corroborates previous observations of overall endocranial conservatism amongst more basal theropods. Several differences of unknown taxonomic utility are noted between the pair. Baryonychine neurosensory capabilities include low-frequency hearing and unexceptional olfaction, whilst the differing morphology of the floccular lobe tentatively suggests less developed gaze stabilisation mechanisms relative to spinosaurines. Given the morphological similarities observed with other basal tetanurans, baryonychines likely possessed comparable behavioural sophistication, suggesting that the transition from terrestrial hypercarnivorous ancestors to semi-aquatic "generalists" during the evolution of Spinosauridae did not require substantial modification of the brain and sensory systems.
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Affiliation(s)
- Chris Tijani Barker
- Institute for Life Sciences, University of Southampton, University Road, Southampton, UK.,Faculty of Engineering and Physical Sciences, University of Southampton, University Road, Southampton, UK
| | - Darren Naish
- School of Biological Sciences, Faculty of Environment and Life Sciences, University of Southampton, University Road, Southampton, UK
| | - Jacob Trend
- School of Biological Sciences, Faculty of Environment and Life Sciences, University of Southampton, University Road, Southampton, UK
| | - Lysanne Veerle Michels
- School of Biological Sciences, Faculty of Environment and Life Sciences, University of Southampton, University Road, Southampton, UK
| | - Lawrence Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio Center for Ecology and Evolutionary Studies, Ohio University, Athens, Ohio, USA
| | - Ryan Ridgley
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio Center for Ecology and Evolutionary Studies, Ohio University, Athens, Ohio, USA
| | - Katy Rankin
- μ-VIS X-ray Imaging Centre, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, UK
| | - Claire E Clarkin
- School of Biological Sciences, Faculty of Environment and Life Sciences, University of Southampton, University Road, Southampton, UK
| | - Philipp Schneider
- Bioengineering Science Research Group, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, UK.,High-Performance Vision Systems, Center for Vision, Automation and Control, AIT Austrian Institute of Technology, Vienna, Austria
| | - Neil J Gostling
- Institute for Life Sciences, University of Southampton, University Road, Southampton, UK.,School of Biological Sciences, Faculty of Environment and Life Sciences, University of Southampton, University Road, Southampton, UK
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10
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Li Z, Wang M, Stidham TA, Zhou Z. Decoupling the skull and skeleton in a Cretaceous bird with unique appendicular morphologies. Nat Ecol Evol 2023; 7:20-31. [PMID: 36593291 DOI: 10.1038/s41559-022-01921-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 10/03/2022] [Indexed: 01/03/2023]
Abstract
The Cretaceous is a critical time interval that encompasses explosive diversifications of terrestrial vertebrates, particularly the period when the earliest-branching birds, after divergence from their theropod ancestors, evolved the characteristic avian Bauplan that led eventually to their global radiation. This early phylogenetic diversity is overwhelmed by the Ornithothoraces, consisting of the Enantiornithes and Ornithuromorpha, whose members evolved key derived features of crown birds. This disparity consequently circumscribes a large morphological gap between these derived clades and the oldest bird Archaeopteryx. The non-ornithothoracine pygostylians, with an intermediate phylogenetic position, are key to deciphering those evolutionary transformations, but progress in their study has been hampered by the limited diversity of known fossils. Here we report an Early Cetaceous non-ornithothoracine pygostylian, Cratonavis zhui gen. et sp. nov., that exhibits a unique combination of a non-avialan dinosaurian akinetic skull with an avialan post-cranial skeleton, revealing the key role of evolutionary mosaicism in early bird diversification. The unusually elongated scapular and metatarsal one preserved in Cratonavis highlights a breadth of skeletal plasticity, stemming from their distinct developmental modules and selection for possibly raptorial behaviour. Mapped changes in these two elements across theropod phylogeny demonstrate clade-specific evolutionary lability.
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Affiliation(s)
- Zhiheng Li
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China.,Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Beijing, China
| | - Min Wang
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China. .,Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Beijing, China.
| | - Thomas A Stidham
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China.,Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zhonghe Zhou
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China.,Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Beijing, China
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11
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Barker CT, Lockwood JA, Naish D, Brown S, Hart A, Tulloch E, Gostling NJ. A European giant: a large spinosaurid (Dinosauria: Theropoda) from the Vectis Formation (Wealden Group, Early Cretaceous), UK. PeerJ 2022; 10:e13543. [PMID: 35702254 PMCID: PMC9188774 DOI: 10.7717/peerj.13543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 05/15/2022] [Indexed: 01/17/2023] Open
Abstract
Postcranial elements (cervical, sacral and caudal vertebrae, as well as ilium, rib and limb bone fragments) belonging to a gigantic tetanuran theropod were recovered from the basal unit (the White Rock Sandstone equivalent) of the Vectis Formation near Compton Chine, on the southwest coast of the Isle of Wight. These remains appear to pertain to the same individual, with enormous dimensions similar to those of the Spinosaurus holotype and exceeding those of the largest European theropods previously reported. A combination of features-including the presence of spinodiapophyseal webbing on an anterior caudal vertebra-suggest that this is a member of Spinosauridae, though a lack of convincing autapomorphies precludes the identification of a new taxon. Phylogenetic analysis supports spinosaurid affinities but we were unable to determine a more precise position within the clade weak support for a position within Spinosaurinae or an early-diverging position within Spinosauridae were found in some data runs. Bioerosion in the form of curved tubes is evident on several pieces, potentially related to harvesting behaviour by coleopteran bioeroders. This is the first spinosaurid reported from the Vectis Formation and the youngest British material referred to the clade. This Vectis Formation spinosaurid is unusual in that the majority of dinosaurs from the Lower Cretaceous units of the Wealden Supergroup are from the fluviolacustrine deposits of the underlying Barremian Wessex Formation. In contrast, the lagoonal facies of the upper Barremian-lower Aptian Vectis Formation only rarely yield dinosaur material. Our conclusions are in keeping with previous studies that emphasise western Europe as a pivotal region within spinosaurid origination and diversification.
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Affiliation(s)
- Chris T. Barker
- Institute for Life Sciences, University of Southampton, Southampton, United Kingdom,Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, United Kingdom
| | - Jeremy A.F. Lockwood
- School of Environment, Geography and Geosciences, University of Portsmouth, Portsmouth, United Kingdom,Department of Earth Sciences, Natural History Museum, London, United Kingdom
| | - Darren Naish
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Sophie Brown
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Amy Hart
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Ethan Tulloch
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Neil J. Gostling
- Institute for Life Sciences, University of Southampton, Southampton, United Kingdom,School of Biological Sciences, University of Southampton, Southampton, United Kingdom
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12
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Mateus O, Estraviz-López D. A new theropod dinosaur from the early cretaceous (Barremian) of Cabo Espichel, Portugal: Implications for spinosaurid evolution. PLoS One 2022; 17:e0262614. [PMID: 35171930 PMCID: PMC8849621 DOI: 10.1371/journal.pone.0262614] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 12/23/2021] [Indexed: 12/01/2022] Open
Abstract
Spinosaurids are some of the most enigmatic Mesozoic theropod dinosaurs due to their unique adaptations to aquatic environments and their relative scarcity. Their taxonomy has proven to be especially problematic. Recent discoveries from Western Europe in general, specifically Iberia, provide some of the best specimens for the understanding of their phylogeny, leading to the description of the spinosaurid Vallibonavenatrix cani and the recognition of the Iberian dinosaur Camarillasaurus cirugedae as one of them. Portuguese associated spinosaurid remains (ML1190) from the Papo Seco Formation (early Barremian) were previously assigned to Baryonyx walkeri but new material recovered in 2020 along with new phylogenetic analyses suggests a different phylogenetic placement, making their revision necessary. Here we show that these remains are not attributable to Baryonyx walkeri, but to a new genus and species, Iberospinus natarioi, gen. et sp. nov. The new taxon is characterized by the presence of a single Meckelian foramen in the Meckelian sulcus, a straight profile of the ventral surface of the dentary and a distal thickening of the acromion process of the pubis between other characters. Iberospinus natarioi is recovered as a sister taxon of the clade formed by Baryonyx and Suchomimus, and outside Spinosaurinae when Vallibonaventrix cani is excluded from the analysis. The description of this taxon reinforces Iberia as a hotspot for spinosaur biodiversity, with several endemic taxa for the region. As expected for the clade, the dentary displays a highly vascularized neurovascular network. The morphometric analysis of parts of the skeleton (pedal phalanx and caudal vertebrae, among others) shows an intermediate condition between basal tetanurans and spinosaurines.
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Affiliation(s)
- Octávio Mateus
- GEOBIOTEC, Department of Earth Sciences, NOVA School of Science and Technology, Caparica, Portugal
- Museu da Lourinhã, Lourinhã, Portugal
| | - Darío Estraviz-López
- GEOBIOTEC, Department of Earth Sciences, NOVA School of Science and Technology, Caparica, Portugal
- Museu da Lourinhã, Lourinhã, Portugal
- * E-mail:
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13
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Subaqueous foraging among carnivorous dinosaurs. Nature 2022; 603:852-857. [PMID: 35322229 DOI: 10.1038/s41586-022-04528-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 02/07/2022] [Indexed: 01/16/2023]
Abstract
Secondary aquatic adaptations evolved independently more than 30 times from terrestrial vertebrate ancestors1,2. For decades, non-avian dinosaurs were believed to be an exception to this pattern. Only a few species have been hypothesized to be partly or predominantly aquatic3-11. However, these hypotheses remain controversial12,13, largely owing to the difficulty of identifying unambiguous anatomical adaptations for aquatic habits in extinct animals. Here we demonstrate that the relationship between bone density and aquatic ecologies across extant amniotes provides a reliable inference of aquatic habits in extinct species. We use this approach to evaluate the distribution of aquatic adaptations among non-avian dinosaurs. We find strong support for aquatic habits in spinosaurids, associated with a marked increase in bone density, which precedes the evolution of more conspicuous anatomical modifications, a pattern also observed in other aquatic reptiles and mammals14-16. Spinosaurids are revealed to be aquatic specialists with surprising ecological disparity, including subaqueous foraging behaviour in Spinosaurus and Baryonyx, and non-diving habits in Suchomimus. Adaptation to aquatic environments appeared in spinosaurids during the Early Cretaceous, following their divergence from other tetanuran theropods during the Early Jurassic17.
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14
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Rotatori FM, Moreno-Azanza M, Mateus O. Reappraisal and new material of the holotype of Draconyx loureiroi (Ornithischia: Iguanodontia) provide insights on the tempo and modo of evolution of thumb-spiked dinosaurs. Zool J Linn Soc 2022. [DOI: 10.1093/zoolinnean/zlab113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
The Upper Jurassic Lourinhã Formation is well known for its rich assemblage of fossil vertebrates. In this formation, ornithopod dinosaurs are represented by two iguanodontian species, Eousdryosaurus nanohallucis and Draconyx loureiroi. We recently became aware of unreported material belonging to the holotype of Draconyx loureiroi, consisting of partially articulated manual elements. We here re-describe the holotype specimen ML 357, including the newly discovered material. The specimen was subjected to CT-scanning and its surface data used to assess anatomical characters. Linear measurements of metatarsal III were used to estimate the body length of the specimen. The Draconyx loureiroi holotype was included in two datasets and analysed with maximum parsimony and Bayesian inference approaches to estimate evolutionary rates among Iguanodontia. We present evidence that Draconyx loureiroi is a valid taxon nested in Styracosterna and is clearly diagnosable by a unique combination of characters. Both maximum parsimony and Bayesian inference indicate high evolutionary rates across the Jurassic/Cretaceous transition for the base of Iguanodontia. Length estimation suggests that Draconyx loureiroi was a relatively small, bipedal and possibly cursorial animal. Given its basal phyletic position, we interpret this bauplan was the ancestral condition for Styracosterna, that only later in the Cretaceous evolved into giant quadrupedal forms.
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Affiliation(s)
- Filippo Maria Rotatori
- GEOBIOTEC, Department of Earth Sciences, NOVA School of Science and Technology, Campus de Caparica, P-2829 516 Caparica, Portugal
- Museu da Lourinhã, Rua João Luis de Moura 95, 2530-158, Lourinhã, Portugal
| | - Miguel Moreno-Azanza
- GEOBIOTEC, Department of Earth Sciences, NOVA School of Science and Technology, Campus de Caparica, P-2829 516 Caparica, Portugal
- Museu da Lourinhã, Rua João Luis de Moura 95, 2530-158, Lourinhã, Portugal
- Grupo Aragosaurus-IUCA, Facultad de Ciencias, Universidad de Zaragoza, 50009, Zaragoza, Spain
| | - Octávio Mateus
- GEOBIOTEC, Department of Earth Sciences, NOVA School of Science and Technology, Campus de Caparica, P-2829 516 Caparica, Portugal
- Museu da Lourinhã, Rua João Luis de Moura 95, 2530-158, Lourinhã, Portugal
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15
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Hendrickx C, Bell PR, Pittman M, Milner ARC, Cuesta E, O'Connor J, Loewen M, Currie PJ, Mateus O, Kaye TG, Delcourt R. Morphology and distribution of scales, dermal ossifications, and other non-feather integumentary structures in non-avialan theropod dinosaurs. Biol Rev Camb Philos Soc 2022; 97:960-1004. [PMID: 34991180 DOI: 10.1111/brv.12829] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/10/2021] [Accepted: 12/14/2021] [Indexed: 12/14/2022]
Abstract
Modern birds are typified by the presence of feathers, complex evolutionary innovations that were already widespread in the group of theropod dinosaurs (Maniraptoriformes) that include crown Aves. Squamous or scaly reptilian-like skin is, however, considered the plesiomorphic condition for theropods and dinosaurs more broadly. Here, we review the morphology and distribution of non-feathered integumentary structures in non-avialan theropods, covering squamous skin and naked skin as well as dermal ossifications. The integumentary record of non-averostran theropods is limited to tracks, which ubiquitously show a covering of tiny reticulate scales on the plantar surface of the pes. This is consistent also with younger averostran body fossils, which confirm an arthral arrangement of the digital pads. Among averostrans, squamous skin is confirmed in Ceratosauria (Carnotaurus), Allosauroidea (Allosaurus, Concavenator, Lourinhanosaurus), Compsognathidae (Juravenator), and Tyrannosauroidea (Santanaraptor, Albertosaurus, Daspletosaurus, Gorgosaurus, Tarbosaurus, Tyrannosaurus), whereas dermal ossifications consisting of sagittate and mosaic osteoderms are restricted to Ceratosaurus. Naked, non-scale bearing skin is found in the contentious tetanuran Sciurumimus, ornithomimosaurians (Ornithomimus) and possibly tyrannosauroids (Santanaraptor), and also on the patagia of scansoriopterygids (Ambopteryx, Yi). Scales are surprisingly conservative among non-avialan theropods compared to some dinosaurian groups (e.g. hadrosaurids); however, the limited preservation of tegument on most specimens hinders further interrogation. Scale patterns vary among and/or within body regions in Carnotaurus, Concavenator and Juravenator, and include polarised, snake-like ventral scales on the tail of the latter two genera. Unusual but more uniformly distributed patterning also occurs in Tyrannosaurus, whereas feature scales are present only in Albertosaurus and Carnotaurus. Few theropods currently show compelling evidence for the co-occurrence of scales and feathers (e.g. Juravenator, Sinornithosaurus), although reticulate scales were probably retained on the mani and pedes of many theropods with a heavy plumage. Feathers and filamentous structures appear to have replaced widespread scaly integuments in maniraptorans. Theropod skin, and that of dinosaurs more broadly, remains a virtually untapped area of study and the appropriation of commonly used techniques in other palaeontological fields to the study of skin holds great promise for future insights into the biology, taphonomy and relationships of these extinct animals.
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Affiliation(s)
- Christophe Hendrickx
- Unidad Ejecutora Lillo, CONICET-Fundación Miguel Lillo, 251 Miguel Lillo, San Miguel de Tucumán, Tucumán, 4000, Argentina
| | - Phil R Bell
- School of Environmental and Rural Science, University of New England, Armidale, NSW, 2351, Australia
| | - Michael Pittman
- Vertebrate Palaeontology Laboratory, Department of Earth Sciences, The University of Hong Kong, Pokfulam, Hong Kong, SAR, China.,Department of Earth Sciences, University College London, WC1E 6BT, United Kingdom
| | - Andrew R C Milner
- St. George Dinosaur Discovery Site at Johnson Farm, 2180 East Riverside Drive, St. George, UT, U.S.A
| | - Elena Cuesta
- Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Str. 10, Munich, 80333, Germany
| | - Jingmai O'Connor
- Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, IL, 60605, U.S.A
| | - Mark Loewen
- Department of Geology and Geophysics, University of Utah, Frederick Albert Sutton Building, 115 South 1460 East, Salt Lake City, UT, 84112, U.S.A.,Natural History Museum of Utah, 301 Wakara Way, Salt Lake City, UT, 84108, U.S.A
| | - Philip J Currie
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Octávio Mateus
- GeoBioTec, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.,Museu da Lourinhã, 95 Rua João Luis de Moura, Lourinhã, 2530-158, Portugal
| | - Thomas G Kaye
- Foundation for Scientific Advancement, 7023 Alhambra Dr., Sierra Vista, AZ, 85650, U.S.A
| | - Rafael Delcourt
- Universidade Estadual de Campinas (UNICAMP), Instituto de Geociências, Cidade Universitária, Rua Carlos Gomes, 250, Campinas, SP, 13083-855, Brazil
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16
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Barker CT, Hone DWE, Naish D, Cau A, Lockwood JAF, Foster B, Clarkin CE, Schneider P, Gostling NJ. New spinosaurids from the Wessex Formation (Early Cretaceous, UK) and the European origins of Spinosauridae. Sci Rep 2021; 11:19340. [PMID: 34588472 PMCID: PMC8481559 DOI: 10.1038/s41598-021-97870-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 08/26/2021] [Indexed: 11/18/2022] Open
Abstract
Spinosaurids are among the most distinctive and yet poorly-known of large-bodied theropod dinosaurs, a situation exacerbated by their mostly fragmentary fossil record and competing views regarding their palaeobiology. Here, we report two new Early Cretaceous spinosaurid specimens from the Wessex Formation (Barremian) of the Isle of Wight. Large-scale phylogenetic analyses using parsimony and Bayesian techniques recover the pair in a new clade within Baryonychinae that also includes the hypodigm of the African spinosaurid Suchomimus. Both specimens represent distinct and novel taxa, herein named Ceratosuchops inferodios gen. et sp. nov. and Riparovenator milnerae gen. et sp. nov. A palaeogeographic reconstruction suggests a European origin for Spinosauridae, with at least two dispersal events into Africa. These new finds provide welcome information on poorly sampled areas of spinosaurid anatomy, suggest that sympatry was present and potentially common in baryonychines and spinosaurids as a whole, and contribute to updated palaeobiogeographic reconstructions for the clade.
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Affiliation(s)
- Chris T Barker
- Institute for Life Sciences, University of Southampton, University Road, Southampton, SO17 1BJ, UK.
- Faculty of Engineering and Physical Sciences, University of Southampton, University Road, Southampton, SO17 1BJ, UK.
| | - David W E Hone
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Darren Naish
- School of Biological Sciences, Faculty of Environment and Life Sciences, University of Southampton, University Road, Southampton, SO17 1BJ, UK
| | | | - Jeremy A F Lockwood
- School of Environment, Geography and Geosciences, University of Portsmouth, Burnaby Road, Portsmouth, PO1 3QL, UK
- Department of Earth Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | | | - Claire E Clarkin
- Institute for Life Sciences, University of Southampton, University Road, Southampton, SO17 1BJ, UK
- School of Biological Sciences, Faculty of Environment and Life Sciences, University of Southampton, University Road, Southampton, SO17 1BJ, UK
| | - Philipp Schneider
- Bioengineering Science Research Group, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, UK
- High-Performance Vision Systems, Center for Vision, Automation and Control, AIT Austrian Institute of Technology, Vienna, Austria
| | - Neil J Gostling
- Institute for Life Sciences, University of Southampton, University Road, Southampton, SO17 1BJ, UK.
- School of Biological Sciences, Faculty of Environment and Life Sciences, University of Southampton, University Road, Southampton, SO17 1BJ, UK.
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17
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Rowe AJ, Snively E. Biomechanics of juvenile tyrannosaurid mandibles and their implications for bite force: Evolutionary biology. Anat Rec (Hoboken) 2021; 305:373-392. [PMID: 33586862 DOI: 10.1002/ar.24602] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 12/25/2022]
Abstract
The tyrannosaurids are among the most well-studied dinosaurs described by science, and analysis of their feeding biomechanics allows for comparison between established tyrannosaurid genera and across ontogeny. 3D finite element analysis (FEA) was used to model and quantify the mechanical properties of the mandibles (lower jaws) of three tyrannosaurine tyrannosaurids of different sizes. To increase evolutionary scope and context for 3D tyrannosaurine results, a broader sample of validated 2D mandible FEA enabled comparisons between ontogenetic stages of Tyrannosaurus rex and other large theropods. It was found that mandibles of small juvenile and large subadult tyrannosaurs experienced lower stress overall because muscle forces were relatively lower, but experienced greater simulated stresses at decreasing sizes when specimen muscle force is normalized. The strain on post-dentary ligaments decreases stress and strain in the posterior region of the dentary and where teeth impacted food. Tension from the lateral insertion of the looping m. ventral pterygoid muscle increases compressive stress on the angular but may decrease anterior bending stress on the mandible. Low mid-mandible bending stresses are congruent with ultra-robust teeth and high anterior bite force in adult T. rex. Mandible strength increases with size through ontogeny in T. rex and phylogenetically among other tyrannosaurids, in addition to that tyrannosaurid mandibles exceed the mandible strength of other theropods at equivalent ramus length. These results may indicate separate predatory strategies used by juvenile and mature tyrannosaurids; juvenile tyrannosaurids lacked the bone-crunching bite of adult specimens and hunted smaller prey, while adult tyrannosaurids fed on larger prey.
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Affiliation(s)
- Andre J Rowe
- School of Earth Sciences, University of Bristol, Bristol, United Kingdom
| | - Eric Snively
- College of Osteopathic Medicine, Oklahoma State University, Tulsa, Oklahoma, USA
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18
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Brownstein CD. Dromaeosaurid crania demonstrate the progressive loss of facial pneumaticity in coelurosaurian dinosaurs. Zool J Linn Soc 2020. [DOI: 10.1093/zoolinnean/zlaa048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Dinosaurs are notable for their extensive skeletal pneumaticity, a feature that may have helped facilitate the development of various ‘extreme’ body plans in this group. Despite its relevance to understanding the evolution of the avian body plan, this feature has only been described in detail for a few non-avian dinosaurs, and cranial pneumaticity outside the braincase remains poorly documented. I describe facial pneumatic features in members of the Dromaeosauridae, a clade of hypercarnivorous dinosaurs closely allied to birds. Variation in the pneumaticity of the nasals and jugals, the position and shape of the pneumatic fenestrae of the maxilla and the border of the antorbital fossa shows that facial pneumaticity differed substantially among closely related dromaeosaurids and other bird-like dinosaurs. Ancestral state reconstructions of facial pneumaticity in coelurosaurs suggest a complex evolutionary history for these features. Surprisingly, the general trend along the path towards birds was the loss or reduction of superficial pneumatic features on the snout and cheek. Some facial pneumatic features seem to have evolved secondarily in some derived bird-like forms. The results show superficial facial pneumaticity did not increase in coelurosaurs and emphasize the complexity of the evolution of pneumatization in the lineage leading to birds.
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19
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Deep-Time Demographic Inference Suggests Ecological Release as Driver of Neoavian Adaptive Radiation. DIVERSITY-BASEL 2020. [DOI: 10.3390/d12040164] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Assessing the applicability of theory to major adaptive radiations in deep time represents an extremely difficult problem in evolutionary biology. Neoaves, which includes 95% of living birds, is believed to have undergone a period of rapid diversification roughly coincident with the Cretaceous–Paleogene (K-Pg) boundary. We investigate whether basal neoavian lineages experienced an ecological release in response to ecological opportunity, as evidenced by density compensation. We estimated effective population sizes (Ne) of basal neoavian lineages by combining coalescent branch lengths (CBLs) and the numbers of generations between successive divergences. We used a modified version of Accurate Species TRee Algorithm (ASTRAL) to estimate CBLs directly from insertion–deletion (indel) data, as well as from gene trees using DNA sequence and/or indel data. We found that some divergences near the K-Pg boundary involved unexpectedly high gene tree discordance relative to the estimated number of generations between speciation events. The simplest explanation for this result is an increase in Ne, despite the caveats discussed herein. It appears that at least some early neoavian lineages, similar to the ancestor of the clade comprising doves, mesites, and sandgrouse, experienced ecological release near the time of the K-Pg mass extinction.
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