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Son M, Lee YN, Zorigt B, Kobayashi Y, Park JY, Lee S, Kim SH, Lee KY. A new juvenile Yamaceratops (Dinosauria, Ceratopsia) from the Javkhlant Formation (Upper Cretaceous) of Mongolia. PeerJ 2022; 10:e13176. [PMID: 35402094 PMCID: PMC8992648 DOI: 10.7717/peerj.13176] [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: 07/08/2021] [Accepted: 03/06/2022] [Indexed: 01/12/2023] Open
Abstract
Here we report a new articulated skeleton of Yamaceratops dorngobiensis (MPC-D 100/553) from the Khugenetjavkhlant locality at the Shine Us Khudag (Javkhlant Formation, ?Santonian-Campanian) of the eastern Gobi Desert, Mongolia, which represents the first substantially complete skeleton and the first juvenile individual of this taxon. The specimen includes a nearly complete cranium and large portions of the vertebral column and appendicular skeleton. Its skull is about 2/3 the size of the holotype specimen, based on mandibular length. Its juvenile ontogenetic stage is confirmed by multiple indicators of skeletal and morphological immaturity known in ceratopsians, such as the long-grained surface texture on the long bones, the smooth external surface on the postorbital, open neurocentral sutures of all caudal vertebrae, a large orbit relative to the postorbital and jugal, the low angle of the lacrimal ventral ramus relative to the maxillary teeth row, narrow frontal, and straight ventral edge of the dentary. Osteohistological analysis of MPC-D 100/553 recovered three lines of arrested growth, implying around 3 years of age when it died, and verified this specimen's immature ontogenetic stage. The specimen adds a new autapomorphy of Yamaceratops, the anteroventral margin of the fungiform dorsal end of the lacrimal being excluded from the antorbital fossa. Furthermore, it shows a unique combination of diagnostic features of some other basal neoceratopsians: the ventrally hooked rostral bone as in Aquilops americanus and very tall middle caudal neural spines about or more than four times as high as the centrum as in Koreaceratops hwaseongensis, Montanoceratops cerorhynchus, and Protoceratops andrewsi. The jugal with the subtemporal ramus deeper than the suborbital ramus as in the holotype specimen is also shared with A. americanus, Liaoceratops yanzigouensis, and juvenile P. andrewsi. Adding 38 new scorings into the recent comprehensive data matrix of basal Neoceratopsia and taking into account the ontogenetically variable characters recovered Y. dorngobiensis as the sister taxon to Euceratopsia (Leptoceratopsidae plus Coronosauria). A second phylogenetic analysis with another matrix for Ceratopsia also supported this position. The new phylogenetic position of Y. dorngobiensis is important in ceratopsian evolution, as this taxon represents one of the basalmost neoceratopsians with a broad, thin frill and hyper-elongated middle caudal neural spines while still being bipedal.
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Affiliation(s)
- Minyoung Son
- School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea,Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, Minnesota, United States
| | - Yuong-Nam Lee
- School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea
| | - Badamkhatan Zorigt
- Institute of Paleontology, Mongolian Academy of Sciences, Ulaanbaatar, Mongolia
| | | | - Jin-Young Park
- School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea
| | - Sungjin Lee
- School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea
| | - Su-Hwan Kim
- School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea
| | - Kang Young Lee
- Department of Physics Education, Gyeongsang National University, Jinju, South Korea
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Ke Y, Wu R, Zelenitsky DK, Brinkman D, Hu J, Zhang S, Jiang H, Han F. A large and unusually thick-shelled turtle egg with embryonic remains from the Upper Cretaceous of China. Proc Biol Sci 2021; 288:20211239. [PMID: 34403631 PMCID: PMC8370798 DOI: 10.1098/rspb.2021.1239] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/22/2021] [Indexed: 11/12/2022] Open
Abstract
Turtle eggs containing embryos are exceedingly rare in the fossil record. Here, we provide the first description and taxonomic identification, to our knowledge, of a fossilized embryonic turtle preserved in an egg, a fossil recovered from the Upper Cretaceous Xiaguan Formation of Henan Province, China. The specimen is attributed to the Nanhsiungchelyidae (Pan-Trionychia), an extinct group of large terrestrial turtles (possibly the species Yuchelys nanyangensis). The egg is rigid, spherical, and is one of the largest and thickest shelled Mesozoic turtle eggs known. Importantly, this specimen allowed identification of other nanhsiungchelyid egg clutches and comparison to those of Adocidae, as Nanhsiungchelyidae and Adocidae form the basal extinct clade Adocusia of the Pan-Trionychia (includes living soft-shelled turtles). Despite the differences in habitat adaptations, nanhsiungchelyids (terrestrial) and adocids (aquatic) shared several reproductive traits, including relatively thick eggshells, medium size clutches and relatively large eggs, which may be primitive for trionychoids (including Adocusia and Carrettochelyidae). The unusually thick calcareous eggshell of nanhsiungchelyids compared to those of all other turtles (including adocids) may be related to a nesting style adaptation to an extremely harsh environment.
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Affiliation(s)
- Yuzheng Ke
- School of Earth Science, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China
| | - Rui Wu
- School of Earth Science, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China
| | - Darla K. Zelenitsky
- Department of Geoscience, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Don Brinkman
- Royal Tyrrell Museum of Palaeontology, Box 7500, Drumheller, Alberta T0J 0Y0, Canada
| | - Jinfeng Hu
- School of Earth Science, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China
| | - Shukang Zhang
- Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, People's Republic of China
| | - Haishui Jiang
- School of Earth Science, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China
| | - Fenglu Han
- School of Earth Science, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China
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A neoceratopsian dinosaur from the early Cretaceous of Mongolia and the early evolution of ceratopsia. Commun Biol 2020; 3:499. [PMID: 32913206 PMCID: PMC7484756 DOI: 10.1038/s42003-020-01222-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 08/11/2020] [Indexed: 11/29/2022] Open
Abstract
Ceratopsia is a diverse dinosaur clade from the Middle Jurassic to Late Cretaceous with early diversification in East Asia. However, the phylogeny of basal ceratopsians remains unclear. Here we report a new basal neoceratopsian dinosaur Beg tse based on a partial skull from Baruunbayan, Ömnögovi aimag, Mongolia. Beg is diagnosed by a unique combination of primitive and derived characters including a primitively deep premaxilla with four premaxillary teeth, a trapezoidal antorbital fossa with a poorly delineated anterior margin, very short dentary with an expanded and shallow groove on lateral surface, the derived presence of a robust jugal having a foramen on its anteromedial surface, and five equally spaced tubercles on the lateral ridge of the surangular. This is to our knowledge the earliest known occurrence of basal neoceratopsian in Mongolia, where this group was previously only known from Late Cretaceous strata. Phylogenetic analysis indicates that it is sister to all other neoceratopsian dinosaurs. Congyu Yu et al. present the partial skull of a new basal neoceratopsian dinosaur from Mongolia. They show that this group is a sister taxon to all other neoceratopsian dinosaurs, and that it occurs earlier in the Cretaceous than previously shown.
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Button DJ, Zanno LE. Repeated Evolution of Divergent Modes of Herbivory in Non-avian Dinosaurs. Curr Biol 2020; 30:158-168.e4. [DOI: 10.1016/j.cub.2019.10.050] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 09/08/2019] [Accepted: 10/25/2019] [Indexed: 01/13/2023]
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Bullar CM, Zhao Q, Benton MJ, Ryan MJ. Ontogenetic braincase development in Psittacosaurus lujiatunensis (Dinosauria: Ceratopsia) using micro-computed tomography. PeerJ 2019; 7:e7217. [PMID: 31428535 PMCID: PMC6698140 DOI: 10.7717/peerj.7217] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 05/31/2019] [Indexed: 11/20/2022] Open
Abstract
Ontogenetic sequences are relatively rare among dinosaurs, with Ceratopsia being one of the better represented clades, and especially among geologically earlier forms, such as Psittacosaurus. Psittacosaurus is a small, bipedal basal ceratopsian abundant in the Lower Cretaceous deposits of Asia, whose cranial and endocranial morphology has been well studied, but only cursory details have been published on the bones surrounding the brain. Using reconstructions created from micro-computed tomography scans of well-preserved skulls from the Barremian–Aptian Yixian Formation, China, we document morphological changes in the braincase of Psittacosaurus lujiatunensis through three growth stages, hatchling, juvenile, and adult, thus providing the first detailed study of ceratopsian braincase morphology through ontogeny. Notable ontogenetic changes in the braincase of P. lujiatunensis include a dramatic relative reduction in size of the supraoccipital, an increase in the lateral expansion of the paroccipital processes and a decrease in the angle between the lateral semicircular canal and the palatal plane. These ontogenetic morphological changes in the braincase relate to expansion of the cranium and brain through growth, as well as reflecting the switch from quadrupedal juveniles to bipedal adults as documented in the changing orientation of the horizontal semicircular canal through ontogeny. Recognition of these patterns in a basal ceratopsian has implications for understanding key events in later ceratopsian evolution, such as the development of the parieto-squamosal frill in derived neoceratopsians.
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Affiliation(s)
- Claire M Bullar
- School of Earth Sciences, University of Bristol, Bristol, UK
| | - Qi Zhao
- School of Earth Sciences, University of Bristol, Bristol, UK.,Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
| | | | - Michael J Ryan
- Department of Earth Sciences, Carleton University, Ottawa, ON, Canada
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Słowiak J, Tereshchenko VS, Fostowicz-Frelik Ł. Appendicular skeleton of Protoceratops andrewsi (Dinosauria, Ornithischia): comparative morphology, ontogenetic changes, and the implications for non-ceratopsid ceratopsian locomotion. PeerJ 2019; 7:e7324. [PMID: 31367485 PMCID: PMC6657679 DOI: 10.7717/peerj.7324] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 06/19/2019] [Indexed: 11/20/2022] Open
Abstract
Protoceratops andrewsi is a well-known ceratopsian dinosaur from the Djadokhta Formation (Upper Cretaceous, Mongolia). Since the 1920s, numerous skeletons of different ontogenetic stages from hatchlings to adults, including fully articulated specimens, have been discovered, but the postcranial anatomy of Protoceratops has not been studied in detail. A new, mostly articulated subadult individual provides an excellent opportunity for us to comprehensively describe the anatomy of the limb skeleton, to compare to other ceratopsian dinosaurs, and to study the ontogenetic and intraspecific variation in this species. New data provided by the specimen shed light on the lifestyle of P. andrewsi. The young subadult individuals present an array of morphological characters intermediate between the bipedal Psittacosaurus and fully quadrupedal adult P. andrewsi. We compare these observations with a broad range of non-ceratopsid Neoceratopsia (of various locomotor adaptations) and Psittacosauridae (obligate bipeds), which gives us insight into the evolution of the skeletal characters informative for the postural change in ceratopsian dinosaurs.
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Affiliation(s)
- Justyna Słowiak
- Department of Evolutionary Paleobiology, Institute of Paleobiology, Polish Academy of Sciences, Warsaw, Poland
| | - Victor S Tereshchenko
- Laboratory of Paleoherpetology, Paleontological Institute, Russian Academy of Sciences, Moscow, Russia
| | - Łucja Fostowicz-Frelik
- Department of Evolutionary Paleobiology, Institute of Paleobiology, Polish Academy of Sciences, Warsaw, Poland.,Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
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Knapp A, Knell RJ, Farke AA, Loewen MA, Hone DWE. Patterns of divergence in the morphology of ceratopsian dinosaurs: sympatry is not a driver of ornament evolution. Proc Biol Sci 2019; 285:rspb.2018.0312. [PMID: 29563271 PMCID: PMC5897650 DOI: 10.1098/rspb.2018.0312] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 03/01/2018] [Indexed: 12/25/2022] Open
Abstract
Establishing the origin and function of unusual traits in fossil taxa provides a crucial tool in understanding macroevolutionary patterns over long periods of time. Ceratopsian dinosaurs are known for their exaggerated and often elaborate horns and frills, which vary considerably between species. Many explanations have been proposed for the origin and evolution of these ‘ornamental’ traits, from predator defence to socio-sexual dominance signalling and, more recently, species recognition. A key prediction of the species recognition hypothesis is that two or more species possessing divergent ornamental traits should have been at least partially sympatric. For the first time to our knowledge, we test this hypothesis in ceratopsians by conducting a comparison of the morphological characters of 46 species. A total of 350 ceratopsian cladistic characters were categorized as either ‘internal’, ‘display’ (i.e. ornamental) or ‘non display’. Patterns of diversity of these characters were evaluated across 1035 unique species pairs. Display characters were found to diverge rapidly overall, but sympatric species were not found to differ significantly in their ornamental disparity from non-sympatric species, regardless of phylogenetic distance. The prediction of the species recognition hypothesis, and thus the idea that ornamentation evolved as a species recognition mechanism, has no statistical support among known ceratopsians.
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Affiliation(s)
| | | | - Andrew A Farke
- Raymond M. Alf Museum of Paleontology, Claremont, CA, USA
| | - Mark A Loewen
- Natural History Museum of Utah, Salt Lake City, UT, USA
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Wang S, Stiegler J, Amiot R, Wang X, Du GH, Clark JM, Xu X. Extreme Ontogenetic Changes in a Ceratosaurian Theropod. Curr Biol 2016; 27:144-148. [PMID: 28017609 DOI: 10.1016/j.cub.2016.10.043] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 10/03/2016] [Accepted: 10/20/2016] [Indexed: 10/20/2022]
Abstract
Ontogenetic variation is documented within many dinosaur species, but extreme ontogenetic changes are rare among dinosaurs, particularly among theropods. Here, we analyze 19 specimens of the Jurassic ceratosaurian theropod Limusaurus inextricabilis, representing six ontogenetic stages based on body size and histological data. Among 78 ontogenetic changes we identify in these specimens, the most unexpected one is the change from fully toothed jaws in the hatchling and juvenile individuals to a completely toothless beaked jaw in the more mature individuals, representing the first fossil record of ontogenetic edentulism among the jawed vertebrates. Jaw morphological data, including those derived from Mi-CT and SR-μCT scanning of Limusaurus specimens, reveal dental alveolar vestiges and indicate that ontogenetic tooth loss in Limusaurus is a gradual, complex process. Our discovery has significant implications for understanding the evolution of the beak, an important feeding structure present in several tetrapod clades, including modern birds. This radical morphological change suggests a dietary shift, probably from omnivory for juvenile Limusaurus to herbivory for adult Limusaurus, which is also supported by additional evidence from gastroliths and stable isotopes. Incorporating new ontogenetic information from Limusaurus into phylogenetic analyses demonstrates surprisingly little effect on its placement when data from different stages are used exclusively, in contrast to previous analyses of tyrannosaurids, but produces subtle differences extending beyond the placement of Limusaurus.
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Affiliation(s)
- Shuo Wang
- Laboratory of Vertebrate Evolution, College of Life Science, Capital Normal University, 105 West 3(rd) Ring Road North, Beijing 100048, China; Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xi-Zhi-Men-Wai Street, Beijing 100044, China.
| | - Josef Stiegler
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
| | - Romain Amiot
- CNRS UMR 5276, Université Claude Bernard Lyon 1 and Ecole Normale Supérieure de Lyon, Villeurbanne Cedex 69622, France
| | - Xu Wang
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, 19 Bei-Tu-Cheng-Xi Road, Beijing 100029, China
| | - Guo-Hao Du
- Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 239 Zhangheng Road, Shanghai 201204, China
| | - James M Clark
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
| | - Xing Xu
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xi-Zhi-Men-Wai Street, Beijing 100044, China.
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Nabavizadeh A, Weishampel DB. The Predentary Bone and Its Significance in the Evolution of Feeding Mechanisms in Ornithischian Dinosaurs. Anat Rec (Hoboken) 2016; 299:1358-88. [PMID: 27490958 DOI: 10.1002/ar.23455] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 06/11/2016] [Accepted: 06/16/2016] [Indexed: 11/10/2022]
Abstract
The characteristic predentary bone in ornithischian dinosaurs is a unique, unpaired element located at the midline of the mandibular symphysis. Although traditionally thought to only be a plant "nipping" bone, the true functional significance of this bone among feeding mechanisms of ornithischian dinosaurs is poorly known. Recent studies of a select few ornithischian genera have suggested rotation of the mandibular corpora around their long axes relative to their midline joint articulation with the predentary bone. This study aims to re-evaluate these hypotheses as well as provide in-depth qualitative comparative descriptions of predentary bone morphology in ornithischian genera throughout all subclades, including heterodontosaurids, thyreophorans, ornithopods, and marginocephalians. Descriptions evaluate overall shape of the predentary, its articular surfaces contacting the rostral ends of the dentaries, and the morphology of the rostral extent of the dentaries and their midline symphysis. Functionally relevant morphologies in each predentary morphotype are accentuated for further speculation of feeding mechanisms. Three predentary morphotypes are described throughout ornithischian subclades and each plays a unique role in feeding adaptations. Most notably, the predentary likely evolved as a midline axial point of the mandibular symphysis for simultaneous variable movement or rotation of the mandibular corpora in many, but not all, taxa. This simultaneous movement of the hemimandibles would have aided in feeding on both sides of the jaw at once. The function of the predentary as well as other jaw adaptations is discussed for genera throughout all subclades, focusing on both general shape and joint morphology. Anat Rec, 299:1358-1388, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Ali Nabavizadeh
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, New Jersey.
| | - David B Weishampel
- Johns Hopkins University School of Medicine, Center for Functional Anatomy and Evolution, Baltimore, Maryland
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