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Yu Y, Zhang C, Xu X. Complex macroevolution of pterosaurs. Curr Biol 2023; 33:770-779.e4. [PMID: 36787747 DOI: 10.1016/j.cub.2023.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 11/13/2022] [Accepted: 01/05/2023] [Indexed: 02/16/2023]
Abstract
Pterosaurs, the earliest flying tetrapods, are the subject of some recent quantitative macroevolutionary analyses from different perspectives.1-2 Here, we use an integrative approach involving newly assembled phylogenetic and body size datasets, net diversification rates, morphological rates, and morphological disparity to gain a holistic understanding of the pterosaur macroevolution. The first two parameters are important in quantitative analyses of macroevolution, but they have been rarely used in previous pterosaur studies.1,3,4,2,5,6,7,8,9,10,11,12 Our study reveals an ∼115-Ma period-from Early Triassic to Early Cretaceous-of multi-wave increasing net diversification rates and disparity, as well as high morphological rates, followed by an ∼65-Ma period-from Early Cretaceous to the end of the Cretaceous-of mostly negative net diversification rates, decreasing disparity, and relatively low morphological rates in pterosaur evolution. Our study demonstrates the following: (1) body size plays an important role in pterosaur lineage diversification during nearly their whole evolutionary history, and the evolution of locomotion, trophic, and ornamental structures also plays a role in different periods; (2) birds, the other major flying tetrapod group at the time, might have affected pterosaur macroevolution for ∼100 Ma; and (3) different mass extinction events might have affected pterosaur evolution differently. Particularly, the revealed decline in pterosaur biodiversity during the Middle and Late Cretaceous periods provides further support for the possible presence of a biodiversity decline of large-sized terrestrial amniotes starting in the mid-Cretaceous,13,14 which may have been caused by multiple factors including a global land area decrease during these periods.
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Affiliation(s)
- Yilun Yu
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Chi Zhang
- 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 100044, China.
| | - Xing Xu
- Centre for Vertebrate Evolutionary Biology, Yunnan University, Kunming, China; Shenyang Normal University, Paleontological Museum of Liaoning, Shenyang, China.
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2
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Zhou CF, Yu D, Zhu Z, Andres B. A new wing skeleton of the Jehol tapejarid Sinopterus and its implications for ontogeny and paleoecology of the Tapejaridae. Sci Rep 2022; 12:10159. [PMID: 35715498 PMCID: PMC9205892 DOI: 10.1038/s41598-022-14111-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 06/01/2022] [Indexed: 11/13/2022] Open
Abstract
The tapejarid pterosaurs flourished in the Jehol Biota with an abundance of immature individuals and a rarity of individuals at skeletal maturity. Most of these individuals plot well on an ontogenetic series based on the proportions of limb elements, but this has lacked histological evidence until now. Here, a new wing skeleton of Sinopterus was thin-sectioned to provide the first histological data about the ontogeny of the Jehol tapejarids. Histologically, the new specimen is an immature individual at a late juvenile stage prior to sexual maturity. It is grouped with medium-sized and medium-crested individuals, which are distinct from the small-sized and crestless individuals as well as the rare large-sized and large-crested individuals at skeletal maturity, supporting the presence of the premaxillary crest as an ontogenetic feature in the Jehol tapejarids. Furthermore, this histology indicates that the largest skeletally immature individuals might have reached the sexual maturity. Enigmatically, there is a size gap between sexual and skeletal maturity, which is at about 79% of the large size, implying a ontogenetic strategy comparable with Pteranodon and possibly with the Brazilian tapejarid Caiuajara. This size gap is consistent with lack of the larger sexually mature individuals in the Jehol Biota, which is hypothesized to be a migratory habitat for the Jehol tapejarids.
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Affiliation(s)
- Chang-Fu Zhou
- College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, Shandong Province, China.
| | - Dongxiang Yu
- College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, Shandong Province, China
| | - Ziheng Zhu
- College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, Shandong Province, China
| | - Brian Andres
- Department of Health, University College Birmingham, Birmingham, UK
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3
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Enriquez NJ, Campione NE, White MA, Fanti F, Sissons RL, Sullivan C, Vavrek MJ, Bell PR. The dinosaur tracks of Tyrants Aisle: An Upper Cretaceous ichnofauna from Unit 4 of the Wapiti Formation (upper Campanian), Alberta, Canada. PLoS One 2022; 17:e0262824. [PMID: 35108301 PMCID: PMC8809565 DOI: 10.1371/journal.pone.0262824] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 01/05/2022] [Indexed: 11/19/2022] Open
Abstract
The Wapiti Formation of northwest Alberta and northeast British Columbia, Canada, preserves an Upper Cretaceous terrestrial vertebrate fauna that is latitudinally situated between those documented further north in Alaska and those from southern Alberta and the contiguous U.S.A. Therefore, the Wapiti Formation is important for identifying broad patterns in vertebrate ecology, diversity, and distribution across Laramidia during the latest Cretaceous. Tracksites are especially useful as they provide a range of palaeoecological, palaeoenvironmental, and behavioural data that are complementary to the skeletal record. Here, we describe the Tyrants Aisle locality, the largest in-situ tracksite known from the Wapiti Formation. The site occurs in the lower part of Unit 4 of the formation (~72.5 Ma, upper Campanian), exposed along the southern bank of the Redwillow River. More than 100 tracks are documented across at least three distinct track-bearing layers, which were deposited on an alluvial floodplain. Hadrosaurid tracks are most abundant, and are referable to Hadrosauropodus based on track width exceeding track length, broad digits, and rounded or bilobed heel margins. We suggest the hadrosaurid trackmaker was Edmontosaurus regalis based on stratigraphic context. Tyrannosaurids, probable troodontids, possible ornithomimids, and possible azhdarchid pterosaurs represent minor but notable elements of the ichnofauna, as the latter is unknown from skeletal remains within the Wapiti Formation, and all others are poorly represented. Possible social behaviour is inferred for some of the hadrosaurid and small theropod-like trackmakers based on trackway alignment, suitable spacing and consistent preservation. On a broad taxonomic level (i.e., family or above), ichnofaunal compositions indicate that hadrosaurids were palaeoecologically dominant across Laramidia during the late Campanian within both high-and low-latitude deposits, although the role of depositional environment requires further testing.
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Affiliation(s)
- Nathan J. Enriquez
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Nicolás E. Campione
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Matt A. White
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Federico Fanti
- Dipartimento di Scienze della Terra e Geologico-Ambientali, Alma Mater Studiorum, Università di Bologna, Bologna, Italy
| | - Robin L. Sissons
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Corwin Sullivan
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- Philip J. Currie Dinosaur Museum, Wembley, Alberta, Canada
| | - Matthew J. Vavrek
- Cutbank Palaeontological Consulting, Grande Prairie, Alberta, Canada
- Department of Natural History, Royal Ontario Museum, Toronto, Ontario, Canada
| | - Phil R. Bell
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
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4
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Aires AS, Reichert LM, Müller RT, Pinheiro FL, Andrade MB. Development and evolution of the notarium in Pterosauria. J Anat 2021; 238:400-415. [PMID: 33026119 PMCID: PMC7812132 DOI: 10.1111/joa.13319] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 08/04/2020] [Accepted: 09/04/2020] [Indexed: 02/03/2023] Open
Abstract
The notarium is the structure formed by fusion of the dorsal vertebrae which occurred independently in pterosaurs and birds. This ankylosis usually involves two to six elements and in many cases, also includes the last cervical vertebra. Fusion can occur in different degrees, uniting the vertebral centra, the neural spines, the transverse processes, the ventral processes, or a combination of these sites. A detailed assessment of the fusion process of pterosaur dorsal vertebrae is still lacking. Here we identify the fusion sequence of pterosaur notarial elements, demonstrating the order of ossification in vertebral bodies and neural spines based on fossils and extant birds. In both Pterosauria and Aves, the notarium generally develops in a antero-posterior direction, but the actual order of each fusion locus may present slight variations. Based on our data, we were able to identify seven developmental stages in the notarium formation, with broad implications for the prediction of ontogenetic stages for the Pterosauria. In addition, we report the occurrence of a notarium in Ardeadactylus longicollum (Kimmeridgian, Southern Germany), the oldest occurrence of this structure in pterosaurs.
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Affiliation(s)
- Alex Schiller Aires
- Programa de Pós‐Graduação em Ecologia e Evolução da BiodiversidadePontifícia Universidade Católica do Rio Grande do SulAvenida Ipiranga6681Porto AlegreBrazil
| | - Leici Machado Reichert
- Programa de Pós‐Graduação em Ecologia e Evolução da BiodiversidadePontifícia Universidade Católica do Rio Grande do SulAvenida Ipiranga6681Porto AlegreBrazil
| | - Rodrigo Temp Müller
- Centro de Apoio à Pesquisa Paleontológica da Quarta ColôniaUniversidade Federal de Santa MariaRua Maximiliano Vizzotto598São João do PolêsineBrazil
| | - Felipe Lima Pinheiro
- Laboratório de PaleobiologiaUniversidade Federal do PampaAvenida Antônio Trilha1847São GabrielBrazil
| | - Marco Brandalise Andrade
- Museu de Ciências e TecnologiaPontifícia Universidade Católica do Rio Grande do Sul (MCT‐PUCRSAvenida Ipiranga6681Porto AlegreBrazil
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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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Kellner AWA, Rodrigues T, Costa FR, Weinschütz LC, Figueiredo RG, Souza GADE, Brum AS, Eleutério LHS, Mueller CW, Sayão JM. Pterodactyloid pterosaur bones from Cretaceous deposits of the Antarctic Peninsula. AN ACAD BRAS CIENC 2019; 91:e20191300. [PMID: 31800676 DOI: 10.1590/0001-3765201920191300] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 11/06/2019] [Indexed: 11/21/2022] Open
Abstract
Fossil vertebrates from Antarctica are considerably rare, hampering our understanding of the evolutionary history of the biota from that continent. For several austral summers, the PALEOANTAR project has been carrying out fieldwork in the Antarctic Peninsula in search for fossils, particularly Cretaceous vertebrates. Among the specimens recovered so far are two bones referable to Pterosauria, more specifically to the Pterodacyloidea, the first volant reptiles from Antarctica to be fully described. MN 7800-V (part and counterpart) was recovered from a moraine at the Abernathy Flats (Santa Marta Formation, Lachman Crags Member, Santonian-Campanian) on James Ross Island. It is interpreted as the distal articulation of a first phalanx of the wing finger, representing an animal with an estimated wingspan between 3 and 4 m. The second specimen (MN 7801-V) comes from Vega Island (Snow Hill Island Formation, Maastrichtian) and is identified as a wing metacarpal IV of an animal with an estimated wingspan from 4 to 5 m. These occurrences show that pterodactyloids inhabited the Antarctic Peninsula at least during the Upper Cretaceous and demonstrate that large pterosaurs were widespread through all parts of the planet during that period.
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Affiliation(s)
- Alexander W A Kellner
- Laboratório de Paleontologia, Departamento de Ciências Biológicas, Centro de Ciências Humanas e Naturais, Universidade Federal do Espírito Santo, Avenida Fernando Ferrari, 514, 29075-910 Vitória, ES, Brazil
| | - Taissa Rodrigues
- Laboratório de Paleontologia, Departamento de Ciências Biológicas, Centro de Ciências Humanas e Naturais, Universidade Federal do Espírito Santo, Avenida Fernando Ferrari, 514, 29075-910 Vitória, ES, Brazil
| | - Fabiana R Costa
- Laboratório de Paleontologia de Vertebrados e Comportamento Animal/LAPC, Centro de Ciências Naturais e Humanas/CCNH, Universidade Federal do ABC, Rua São Paulo, s/n, Jardim Antares, 09606-045 São Bernardo do Campo, SP, Brazil
| | - Luiz C Weinschütz
- CENPALEO - Centro Paleontológico da Universidade do Contestado, Universidade do Contestado, 89306-076 Mafra, SC, Brazil
| | - Rodrigo G Figueiredo
- Departamento de Biologia, Universidade Federal do Espírito Santo, Alto Universitário, s/n, Guararema, 29500-000 Alegre, ES, Brazil
| | - Geovane A DE Souza
- Laboratory of Systematics and Taphonomy of Fossil Vertebrates, Departamento de Geologia e Paleontologia, Museu Nacional/Universidade Federal do Rio de Janeiro, Quinta da Boa Vista s/n, São Cristóvão, 20940-040 Rio de Janeiro, RJ, Brazil
| | - Arthur S Brum
- Laboratory of Systematics and Taphonomy of Fossil Vertebrates, Departamento de Geologia e Paleontologia, Museu Nacional/Universidade Federal do Rio de Janeiro, Quinta da Boa Vista s/n, São Cristóvão, 20940-040 Rio de Janeiro, RJ, Brazil
| | - Lúcia H S Eleutério
- Laboratório de Paleobiologia e Microestruturas, Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Rua do Alto Reservatório, s/n, Bela Vista, 55608-680 Vitória do Santo Antão, PE, Brazil.,Programa de Pós-Graduação em Geociências, Universidade Federal de Pernambuco/UFPE, Centro de Tecnologia e Geociências, Av. da Arquitetura, s/n, Cidade Universitária, 50740-550 Recife, PE, Brazil
| | - Carsten W Mueller
- Technical University of Munich, Chair of Soil Science, Emil-Ramann-Strasse 2, 85354, Freising-Weihenstephan, Germany
| | - Juliana M Sayão
- Laboratory of Systematics and Taphonomy of Fossil Vertebrates, Departamento de Geologia e Paleontologia, Museu Nacional/Universidade Federal do Rio de Janeiro, Quinta da Boa Vista s/n, São Cristóvão, 20940-040 Rio de Janeiro, RJ, Brazil.,Laboratório de Paleobiologia e Microestruturas, Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Rua do Alto Reservatório, s/n, Bela Vista, 55608-680 Vitória do Santo Antão, PE, Brazil
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7
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Navarro CA, Martin-Silverstone E, Stubbs TL. Morphometric assessment of pterosaur jaw disparity. ROYAL SOCIETY OPEN SCIENCE 2018; 5:172130. [PMID: 29765665 PMCID: PMC5936930 DOI: 10.1098/rsos.172130] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 03/26/2018] [Indexed: 05/28/2023]
Abstract
Pterosaurs were a successful group of Mesozoic flying reptiles. They were the first vertebrate group to achieve powered flight and varied enormously in morphology and ecology, occupying a variety of niches and developing specialized feeding strategies. Ecomorphological principles suggest this variation should be reflected by great morphological diversity in the lower jaw, given that the mandible served as the primary apparatus for prey acquisition. Here we present the first study of mandibular shape disparity in pterosaurs and aim to characterize major aspects of variation. We use a combination of geometric morphometric approaches, incorporating both outline analysis using elliptical Fourier analysis and semi-landmark approaches. Our results show that morphological convergence is prevalent and many pterosaurs, belonging to diverse dietary groups and subclades, overlap in morphospace and possessed relatively simple 'rod-shaped' jaws. There is no clear trend of size distributions in pterosaur mandibular morphospace, and larger forms are widely distributed. Additionally, there is limited functional signal within pterosaur lower jaw morphospace. Instead, the development of a large anterior ventral crest represents the major component of disparity. This suggests that a socio-sexual trait was a key driver for innovation in pterosaur lower jaw shape.
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Affiliation(s)
- Charlie A. Navarro
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK
| | - Elizabeth Martin-Silverstone
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK
- Ocean and Earth Science, National Oceanography Centre, University of Southampton, European Way, Southampton SO14 3ZH, UK
| | - Thomas L. Stubbs
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK
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8
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Longrich NR, Martill DM, Andres B. Late Maastrichtian pterosaurs from North Africa and mass extinction of Pterosauria at the Cretaceous-Paleogene boundary. PLoS Biol 2018. [PMID: 29534059 PMCID: PMC5849296 DOI: 10.1371/journal.pbio.2001663] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Pterosaurs were the first vertebrates to evolve powered flight and the largest animals to ever take wing. The pterosaurs persisted for over 150 million years before disappearing at the end of the Cretaceous, but the patterns of and processes driving their extinction remain unclear. Only a single family, Azhdarchidae, is definitively known from the late Maastrichtian, suggesting a gradual decline in diversity in the Late Cretaceous, with the Cretaceous–Paleogene (K-Pg) extinction eliminating a few late-surviving species. However, this apparent pattern may simply reflect poor sampling of fossils. Here, we describe a diverse pterosaur assemblage from the late Maastrichtian of Morocco that includes not only Azhdarchidae but the youngest known Pteranodontidae and Nyctosauridae. With 3 families and at least 7 species present, the assemblage represents the most diverse known Late Cretaceous pterosaur assemblage and dramatically increases the diversity of Maastrichtian pterosaurs. At least 3 families—Pteranodontidae, Nyctosauridae, and Azhdarchidae—persisted into the late Maastrichtian. Late Maastrichtian pterosaurs show increased niche occupation relative to earlier, Santonian-Campanian faunas and successfully outcompeted birds at large sizes. These patterns suggest an abrupt mass extinction of pterosaurs at the K-Pg boundary. Pterosaurs were winged cousins of the dinosaurs and lived from around 200 million years ago to 66 million years ago, when the last pterosaurs disappeared during the Cretaceous-Paleogene extinction that wiped out the dinosaurs. The pterosaurs are thought to have declined in diversity before their final extinction, suggesting that gradual processes played a major role in their demise. However, pterosaur fossils are very rare, and thus, it is unclear whether pterosaurs were really low in diversity at this time or whether these patterns merely result from a paucity of fossils. We describe new pterosaur fossils from the end of the Cretaceous in Morocco, including as many as 7 species. They represent 3 different families and show a large range of variation in size and skeletal proportions, suggesting that they occupied a wide range of ecological niches.
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Affiliation(s)
- Nicholas R. Longrich
- Department of Biology and Biochemistry and Milner Centre for Evolution, University of Bath, Bath, United Kingdom
- * E-mail:
| | - David M. Martill
- School of Earth and Environmental Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Brian Andres
- Vertebrate Paleontology Laboratory, The University of Texas at Austin, Austin, Texas, United States of America
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9
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McLachlan SMS, Kaiser GW, Longrich NR. Maaqwi cascadensis: A large, marine diving bird (Avialae: Ornithurae) from the Upper Cretaceous of British Columbia, Canada. PLoS One 2017; 12:e0189473. [PMID: 29220405 PMCID: PMC5722380 DOI: 10.1371/journal.pone.0189473] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 11/28/2017] [Indexed: 11/18/2022] Open
Abstract
Mesozoic bird fossils from the Pacific Coast of North America are rare, but small numbers are known from the Late Cretaceous aged sediments of Hornby Island, British Columbia. Most are unassociated fragments that offer little information, but additional preparation of a large coracoid has revealed more details of its structure, as well as three associated wing bones. Phylogenetic analysis suggests that Maaqwi cascadensis, gen. et sp. nov. represents a derived crown or near-crown member of Ornithurae, and specifically suggests affinities with Vegaviidae. M. cascadensis is characterized by large size, and regressions based on dimensions of the coracoid suggest a large bird, with an estimated body mass of approximately 1.5 kilograms. The bones are robust, with thick walls, suggesting that M. cascadensis was a bird adapted for diving, similar to modern loons and grebes. The wings are short, while the coracoid is unusually short and broad, similar to modern loons. Along with the Ichthyornithes and Hesperornithes, M. cascadensis and Vegaviidae appear to represent a third clade of bird that evolved to exploit marine habitats in the Late Cretaceous, one specialized for foot-propelled diving and rapid cruising flight over water.
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Affiliation(s)
- Sandy M. S. McLachlan
- School of Earth & Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada
- Department of Natural History, Royal BC Museum, Victoria, British Columbia, Canada
- * E-mail:
| | - Gary W. Kaiser
- Department of Natural History, Royal BC Museum, Victoria, British Columbia, Canada
| | - Nicholas R. Longrich
- Department of Biology and Biochemistry, and Milner Centre for Evolution, University of Bath, Bath, United Kingdom
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10
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Chan NR. Morphospaces of functionally analogous traits show ecological separation between birds and pterosaurs. Proc Biol Sci 2017; 284:rspb.2017.1556. [PMID: 29046377 DOI: 10.1098/rspb.2017.1556] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 09/19/2017] [Indexed: 11/12/2022] Open
Abstract
Birds originated and radiated in the presence of another group of flying vertebrates, the pterosaurs. Opinion is divided as to whether birds competitively displaced pterosaurs from small-body size niches or whether the two groups coexisted with little competition. Previous studies of Mesozoic birds and pterosaurs compared measurements of homologous limb bones to test these hypotheses. However, these characters probably reflect differing ancestries rather than ecologies. Here, competition and ecological separation were tested for using multivariate analyses of functionally equivalent morphological characters. As well as using characters from the fore- and hindlimbs, these analyses also included measurements of the lower jaw. The results of this study indicate that pterosaurs had relatively longer jaws, shorter metatarsals and shorter brachial regions compared with birds of similar size. Contrary to the results of previous studies, the distal wing was not important for separating the two clades in morphospace owing to the inclusion of the primary feathers in this unit. The differences found here indicate ecological separation based on differences in size, locomotory features and feeding adaptations. Thus, instead of one group displacing the other, birds and pterosaurs appear to have adopted distinctive ecological strategies throughout their period of coexistence.
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Affiliation(s)
- Nicholas R Chan
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
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Wu WH, Zhou CF, Andres B. The toothless pterosaur Jidapterus edentus (Pterodactyloidea: Azhdarchoidea) from the Early Cretaceous Jehol Biota and its paleoecological implications. PLoS One 2017; 12:e0185486. [PMID: 28950013 PMCID: PMC5614613 DOI: 10.1371/journal.pone.0185486] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 09/13/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND In the Early Cretaceous Jehol Biota, the toothless pterosaurs flourished with the chaoyangopterids and tapejarids playing a key role in understanding the early diversity and evolution of the Azhdarchoidea. Unlike the more diverse tapejarids, the rarer chaoyangopterids are characterized by a long and low rostrum, supporting a close relationship with the huge azhdarchids. Unfortunately, our knowledge is still limited in the osteology, paleoecology, and taxonomy of the Chaoyangopteridae. As one of the best preserved skeletons, the type and only specimen of Jidapterus edentus provides an opportunity to understand the morphology and paleoecology of the chaoyangopterids. RESULTS Our study of the osteology of Jidapterus edentus reveals valuable information about the morphology of the Chaoyangopteridae such as a rostrum with a curved dorsal profile, high Rostral Index (RI), larger angle between the dorsal and postorbital processes of the jugal, sequentially shorter fourth to seventh cervical vertebrae, sternum with a plate wider than long, contact of the metacarpal I with the distal syncarpal, pneumatic foramen on first wing phalanx, hatchet-like postacetabular process with unconstricted neck and small dorsal process, distinctly concave anterior margin of pubis, subrectangular pubic plate with nearly parallel anterior and posterior margins, longer proximal phalanges of pedal digits III and IV, as well as reduced and less curved pedal unguals. These features further support the validity of Jidapterus edentus as a distinct species and the close relationship of the chaoyangopterids with the azhdarchids. Paleoecologically, the chaoyangopterids are probably like the azhdarchids, more terrestrial than the contemporaneous and putatively arboreal tapejarids, which may have been limited to the forest-dominated ecosystem of the Jehol Biota. DISCUSSION The osteology of Jidapterus edentus further supports the close relationship of the Chaoyangopteridae with the Azhdarchidae in sharing a high RI value and reduced and mildly-curved pedal unguals, and it also implies a possible paleoecological similarity in their terrestrial capability. Combined with the putatively arboreal and herbivorous tapejarids, this distinct lifestyle of the chaoyangopterids provides new insights into the diversity of pterosaurs in the ecosystem of the Jehol Biota.
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Affiliation(s)
- Wen-Hao Wu
- Key Laboratory for Evolution of Past Life and Environment in Northeast Asia, Ministry of Education, Jilin University, Changchun, Jilin, China
- Research Center of Palaeontology & Stratigraphy, Jilin University, Changchun, Jilin, China
| | - Chang-Fu Zhou
- College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, Shandong, China
- Paleontological Institute, Shenyang Normal University, Shenyang, Liaoning, China
| | - Brian Andres
- Department and Earth and Environmental Science, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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Naish D, Witton MP. Neck biomechanics indicate that giant Transylvanian azhdarchid pterosaurs were short-necked arch predators. PeerJ 2017; 5:e2908. [PMID: 28133577 PMCID: PMC5248582 DOI: 10.7717/peerj.2908] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 12/13/2016] [Indexed: 11/20/2022] Open
Abstract
Azhdarchid pterosaurs include the largest animals to ever take to the skies with some species exceeding 10 metres in wingspan and 220 kg in mass. Associated skeletons show that azhdarchids were long-necked, long-jawed predators that combined a wing planform suited for soaring with limb adaptations indicative of quadrupedal terrestrial foraging. The postcranial proportions of the group have been regarded as uniform overall, irrespective of their overall size, notwithstanding suggestions that minor variation may have been present. Here, we discuss a recently discovered giant azhdarchid neck vertebra referable to Hatzegopteryx from the Maastrichtian Sebeş Formation of the Transylvanian Basin, Romania, which shows how some azhdarchids departed markedly from conventional views on their proportions. This vertebra, which we consider a cervical VII, is 240 mm long as preserved and almost as wide. Among azhdarchid cervicals, it is remarkable for the thickness of its cortex (4–6 mm along its ventral wall) and robust proportions. By comparing its dimensions to other giant azhdarchid cervicals and to the more completely known necks of smaller taxa, we argue that Hatzegopteryx had a proportionally short, stocky neck highly resistant to torsion and compression. This specimen is one of several hinting at greater disparity within Azhdarchidae than previously considered, but is the first to demonstrate such proportional differences within giant taxa. On the assumption that other aspects of Hatzegopteryx functional anatomy were similar to those of other azhdarchids, and with reference to the absence of large terrestrial predators in the Maastrichtian of Transylvania, we suggest that this pterosaur played a dominant predatory role among the unusual palaeofauna of ancient Haţeg.
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Affiliation(s)
- Darren Naish
- Ocean and Earth Science, University of Southampton, Southampton, UK
| | - Mark P Witton
- School of Earth & Environmental Sciences, University of Portsmouth, Portsmouth, United Kingdom
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Tiny pterosaurs' tenure extended. Nature 2016; 537:141. [DOI: 10.1038/537141b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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14
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Tiny pterosaur claims new perch on reptile family tree. Nature 2016. [DOI: 10.1038/nature.2016.20507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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