DOCSLIB.ORG

Ontogenetic Stages of Ceratopsian Dinosaur Psittacosaurus in Bone Histology

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Ontogenetic Stages of Ceratopsian Dinosaur Psittacosaurus in Bone Histology Ontogenetic stages of ceratopsian dinosaur Psittacosaurus in bone histology QI ZHAO, MICHAEL J. BENTON, SHOJI HAYASHI, and XING XU Zhao, Q., Benton, M.J., Hayashi, S., and Xu, X. 2019. Ontogenetic stages of ceratopsian dinosaur Psittacosaurus in bone histology. Acta Palaeontologica Polonica 64 (2): 323–334. The early ceratopsians Psittacosaurus and Protoceratops have provided important information on dinosaurian develop- ment because of abundant specimens of adults, subadults, juveniles, and even hatchlings. Here we present new data and methods for identifying key growth stages from bone histology. Previous studies on Psittacosaurus lujiatunensis from the Early Cretaceous Jehol Biota of China did not present in-depth analysis of growth patterns. Based on a histological study of 43 thin sections from 17 individuals of this species, we recognize four histological ontogenetic stages, i.e., hatchling, juvenile, sub-adult, and adult, but no fully-grown stage. We estimate life history and longevity from diaphyseal growth line counts and other features of histology. We show that P. lujiatunensis grew fast in early stages (hatchling, juvenile, and subadult), according to the density of vascular canals and the different type of bone tissue; the deposition of parallel fibred bone tissue in the outer cortex of the subadult stage indicates that growth rate was slowing down. We introduce a new graphical method to estimate the occurrence and volumes of vascular canals from thin sections more accurately than current two-dimensional approaches. Key words: Dinosauria, Ceratopsia, bone histology, ontogeny, growth patterns, longevity, Cretaceous, China. Qi Zhao [[email protected]] and Xing Xu [[email protected]], Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology; and Center for Excellence in Life and Paleoenvi- ronment, Chinese Academy of Sciences, Beijing 100044, China. Michael J. Benton [[email protected]], School of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK. Shoji Hayashi [[email protected]], Department of Biosphere-Geosphere Science, Okayama University of Science, Okayama, 700-0005, Japan. Received 18 October 2018, accepted 29 January 2019, available online 4 March 2019. Copyright © 2019 Q. Zhao et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License (for details please see http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Institute of Vertebrate Paleontology and Paleoanthropology Introduction (Beijing, China), showing various ontogenetic stages. These provide a unique opportunity to explore character changes Several studies on dinosaurs (e.g., Erickson and Tumanova 2000; Horner et al. 2000; Klein and Sander 2008; Klein et al. through ontogeny and establish the life history and growth 2009) have demonstrated that histological sections of fossil pattern for Psittacosaurus lujiatunensis. bone samples can be used to establish the relative age/onto- The key assumption behind establishing the age of rep- genetic stage of specimens. The bones of prematurely dead tiles and mammals by skeletochronology is that the region young dinosaurs may well record their ontogenetic history, between the two neighbouring LAGs (lines of arrested as shown by Woodward et al. (2014) in alligators, and by growth) represents one year of growth, with the LAG indi- Woodward et al. (2015) in Maiasaura. However, this is gener- cating a temporary cessation of growth in winter or another ally not the case with bones of older individuals, because re- unfavourable season (Francillon-Vieillot et al. 1990; Ricqlès modelling during growth can remove any number of growth et al. 1991; Castanet et al. 1993; Sander and Klein 2005; rings in the centre of the bone. In such cases, it is necessary to Köhler et al. 2012). The LAG is marked by a darker band in look at more than one bone, and instead a series of bones from thin section, representing the increased density of the bone individuals of the same species, whose age can be estimated, as a result of less bone deposition and fewer canals formed can provide overlapping histological records of younger and within a fixed amount of time. older individuals to elucidate the full ontogenetic growth tra- Using this approach, Erickson and colleagues sought jectory for the species (Zhao et al. 2013). There are many to reconstruct life tables and assumed logistic growth Psittacosaurus skeletons, including juveniles to adults, in the curves for a variety of dinosaurs, such as Tyrannosaurus, Acta Palaeontol. Pol. 64 (2): 323–334, 2019 https://doi.org/10.4202/app.00559.2018 324 ACTA PALAEONTOLOGICA POLONICA 64 (2), 2019 Oviraptor, and Psittacosaurus (Erickson and Tumanova Table 1. Numbers of LAGs in individual thin sections made during this 2000; Erickson et al. 2001, 2004, 2006, 2007, 2009; Erickson study. Values in parentheses represent additional LAGs that are inferred 2005;). The methods have attracted a great deal of attention, to have been obliterated by expansion of the medullary cavity. An age even though they have been criticised by Sander et al. (2004) estimate is given for each specimen, based on the evidence from all thin sections taken for that specimen. For IVPP V12617, the cross-section because some dinosaurs such as sauropods grew very fast through the radius suggests a younger age (seven years) than cross-sec- and show limited data on their earlier years in bone sections. tions through the other sampled bones (ten years). However, only one New work on large mammals (Köhler et al. 2012) has shown juvenile radius was sectioned in this study, and it is possible that we have that older assumptions that LAGs are associated only with underestimated the number of LAGs obliterated by medullary cavity ectothermic physiologies are incorrect. Modern ruminant expansion in the radius of IVPP V12617. mammals also show evidence of cyclical growth. Growth Repository slows or stops during the unfavourable season, associated Humerus Ulna Radius Femur Tibia Fibula Age number with reductions in body temperature, metabolic rate, and IVPP V16902.1 0 0 <1 suppression of bone growth regulators. The occurrence of IVPP V16902.2 0 0 <1 dry seasons, for example, can drive patterns where, for ex- IVPP V16902.3 0 <1 ample, there might be two episodes of starvation in a year ELDM V1037 1 1 and hence two LAGs (Castanet 2006). ELDM V1038.21 2 2 2 2 2 We assume that the use of LAGs to indicate age is most ELDM V1038.15 2 2 2 reliable when juveniles and adults are sampled from the ELDM V1038.11 2 2 2 2 2 2 same locality, which means that the individual animals all IVPP V14341.2 2 2 2 experienced similar climate cycles. By superimposing the IVPP V14341.3 2 2 2 drawing of LAGs and determining numbers of LAGs, age at IVPP V14341.4 2 2 2 death can be determined for Psittacosaurus, using methods IVPP V14341.5 2 2 2 and data presented by Zhao et al. (2013). IVPP V14341.6 2 2 2 2 Previous work on the bone histology of Psittacosaurus in- IVPP V14341.1 3 3 2 (1) 3 3 cludes a detailed study of ontogenetic stages in P. mongolien- IVPP V14748 3 (2) 3 (2) 5 sis by Erickson and Tumanova (2000) and a similar study on IVPP V18344 4 (2) 3 (3) 5 (2) 6 (1) 7 P. lujiatunensis by Erickson et al. (2009). In our earlier work IVPP V18343 5 (3) 8 (1) 9 (Zhao et al. 2013), we addressed questions of age estimates IVPP V12617 7 (3) 5 (2) 8 (2) 10 and evidence for differential bone growth rates related to a postural shift from quadrupedal juveniles to bipedal adults. nae, radii, femora, tibiae, and fibulae (Table 1). The sample In this study, we describe the histological ontogenetic spans a growth series from hatchling to adult developmental changes in Psittacosaurus lujiatunensis in further detail stages, determined according to life history and longev- and compare these with the previous histological work on ity estimates based on diaphyseal growth line counts, the P. mongoliensis. Our aim is to explore the bone histology of growth stages of osteons and other features of histology, each growth stage of P. lujiatunensis, in particular present- as explained by Zhao et al. (2013). The broad assumption, ing the changes in histological tissue types as shown by con- as in other studies of dinosaurs, is that the LAGs represent fidently aged individuals. We report that the growth pattern approximate annual growth indicators. in bone histology is different between these two species, and We were inclined to accept this simple correlation of we develop this theme further as an example to show the LAG numbers and age as reasonably accurate, for younger complexity of growth patterns in dinosaurs. individuals at least, as multiple juveniles from a single clutch of six specimens (IVPP V14341) showed comparable Institutional abbreviations.— ELDM, Erlianhaote Dinosaur patterns of LAGs, five of them being two years old, and Museum, Eerenhot, Inner Mongolia, China; IVPP, Institute one slightly larger individual three years old (Zhao et al. of Vertebrate Paleontology and Paleoanthropology, Beijing, 2013). In older individuals, we explored geometric ways to China. detect whether early LAGs had been resorbed by medullary Other abbreviations.—EFS, External Fundamental System; cavities. For example, we took thin sections of the humerus, LAG, line of arrested growth. femur, tibia, and fibula from the largest of six individuals of Psittacosaurus lujiatunensis (IVPP V14341.1). Following different rates of medullary cavity expansion in each bone, Material and methods we found three LAGs in the humerus, femur, and fibula, but just two LAGs in the tibia. The medullary cavity must Material and age estimation.—In this study, 17 individuals have absorbed the first-year LAG in the tibia.
Load more

Recommended publications
  • A Neoceratopsian Dinosaur from the Early Cretaceous of Mongolia And
    ARTICLE https://doi.org/10.1038/s42003-020-01222-7 OPEN A neoceratopsian dinosaur from the early Cretaceous of Mongolia and the early evolution of ceratopsia ✉ Congyu Yu 1 , Albert Prieto-Marquez2, Tsogtbaatar Chinzorig 3,4, Zorigt Badamkhatan4,5 & Mark Norell1 1234567890():,; 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 pre- maxillary 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. 1 Division of Vertebrate Paleontology, American Museum of Natural History, New York 10024, USA. 2 Institut Català de Paleontologia Miquel Crusafont, ICTA-ICP, Edifici Z, c/de les Columnes s/n Campus de la Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès Sabadell, Barcelona, Spain. 3 Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA. 4 Institute of Paleontology, Mongolian Academy of Sciences, ✉ Ulaanbaatar 15160, Mongolia.
    [Show full text]
  • A Phylogenetic Analysis of the Basal Ornithischia (Reptilia, Dinosauria)
    A PHYLOGENETIC ANALYSIS OF THE BASAL ORNITHISCHIA (REPTILIA, DINOSAURIA) Marc Richard Spencer A Thesis Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements of the degree of MASTER OF SCIENCE December 2007 Committee: Margaret M. Yacobucci, Advisor Don C. Steinker Daniel M. Pavuk © 2007 Marc Richard Spencer All Rights Reserved iii ABSTRACT Margaret M. Yacobucci, Advisor The placement of Lesothosaurus diagnosticus and the Heterodontosauridae within the Ornithischia has been problematic. Historically, Lesothosaurus has been regarded as a basal ornithischian dinosaur, the sister taxon to the Genasauria. Recent phylogenetic analyses, however, have placed Lesothosaurus as a more derived ornithischian within the Genasauria. The Fabrosauridae, of which Lesothosaurus was considered a member, has never been phylogenetically corroborated and has been considered a paraphyletic assemblage. Prior to recent phylogenetic analyses, the problematic Heterodontosauridae was placed within the Ornithopoda as the sister taxon to the Euornithopoda. The heterodontosaurids have also been considered as the basal member of the Cerapoda (Ornithopoda + Marginocephalia), the sister taxon to the Marginocephalia, and as the sister taxon to the Genasauria. To reevaluate the placement of these taxa, along with other basal ornithischians and more derived subclades, a phylogenetic analysis of 19 taxonomic units, including two outgroup taxa, was performed. Analysis of 97 characters and their associated character states culled, modified, and/or rescored from published literature based on published descriptions, produced four most parsimonious trees. Consistency and retention indices were calculated and a bootstrap analysis was performed to determine the relative support for the resultant phylogeny. The Ornithischia was recovered with Pisanosaurus as its basalmost member.
    [Show full text]
  • A Revision of the Ceratopsia Or Horned Dinosaurs
    MEMOIRS OF THE PEABODY MUSEUM OF NATURAL HISTORY VOLUME III, 1 A.R1 A REVISION orf tneth< CERATOPSIA OR HORNED DINOSAURS BY RICHARD SWANN LULL STERLING PROFESSOR OF PALEONTOLOGY AND DIRECTOR OF PEABODY MUSEUM, YALE UNIVERSITY LVXET NEW HAVEN, CONN. *933 MEMOIRS OF THE PEABODY MUSEUM OF NATURAL HISTORY YALE UNIVERSITY Volume I. Odontornithes: A Monograph on the Extinct Toothed Birds of North America. By Othniel Charles Marsh. Pp. i-ix, 1-201, pis. 1-34, text figs. 1-40. 1880. To be obtained from the Peabody Museum. Price $3. Volume II. Part 1. Brachiospongidae : A Memoir on a Group of Silurian Sponges. By Charles Emerson Beecher. Pp. 1-28, pis. 1-6, text figs. 1-4. 1889. To be obtained from the Peabody Museum. Price $1. Volume III. Part 1. American Mesozoic Mammalia. By George Gaylord Simp- son. Pp. i-xvi, 1-171, pis. 1-32, text figs. 1-62. 1929. To be obtained from the Yale University Press, New Haven, Conn. Price $5. Part 2. A Remarkable Ground Sloth. By Richard Swann Lull. Pp. i-x, 1-20, pis. 1-9, text figs. 1-3. 1929. To be obtained from the Yale University Press, New Haven, Conn. Price $1. Part 3. A Revision of the Ceratopsia or Horned Dinosaurs. By Richard Swann Lull. Pp. i-xii, 1-175, pis. I-XVII, text figs. 1-42. 1933. To be obtained from the Peabody Museum. Price $5 (bound in cloth), $4 (bound in paper). Part 4. The Merycoidodontidae, an Extinct Group of Ruminant Mammals. By Malcolm Rutherford Thorpe. In preparation.
    [Show full text]
  • A Battering Ram?
    A Battering Ram? All evidence suggests that Pachycephalosaur skulls were built to withstand extreme forces 9 inches of solid bone Bone organized in a radial arrangement- structural support Articulation btw back of skull and vertebrae oriented to transfer forces linearly Articulation btw back of skull and vertebral column built to withstand sideways forces Vertebral column has tongue and groove articulations Spinal column is an S-shaped shock absorber BUT There is no ‘locking’ mechanism on skull to keep battering heads aligned Some Pachycephalosaurs have imprinted blood vessels on dome These factors suggests that head- butting may not be likely Intraspecies Competition (typically male-male) Females are typically choosey Why? Because they have more to loose Common rule in biology: Females are expensive to lose, males are cheap (e.g. deer hunting) Females choose the male most likely to provide the most successful offspring Males compete with each other for access to female vs. female chooses the strongest male Choosey females // Strong males have more offspring => SEXUAL selection Many ways to do this... But: In general, maximize competition and minimize accidental deaths (= no fitness) http://www.youtube.com/watch?v=PontCXFgs0M http://www.metacafe.com/watch/1941236/giraffe_fight/ http://www.youtube.com/watch? http://www.youtube.com/watch?v=DYDx1y38vGw http://www.youtube.com/watch?v=ULRtdk-3Yh4 Air-filled horn cores vs. solid bone skull caps... Gotta have a cheezy animated slide. Homalocephale Pachycephalosaurus Prenocephale Tylocephale Stegoceras Head butting Pachycephalosaurs Bone structure was probably strong enough to withstand collision Convex nature would favor glancing blows Instead, dome and spines seem better suited for “flank butting” So..
    [Show full text]
  • A New Maastrichtian Species of the Centrosaurine Ceratopsid Pachyrhinosaurus from the North Slope of Alaska
    A new Maastrichtian species of the centrosaurine ceratopsid Pachyrhinosaurus from the North Slope of Alaska ANTHONY R. FIORILLO and RONALD S. TYKOSKI Fiorillo, A.R. and Tykoski, R.S. 2012. A new Maastrichtian species of the centrosaurine ceratopsid Pachyrhinosaurus from the North Slope of Alaska. Acta Palaeontologica Polonica 57 (3): 561–573. The Cretaceous rocks of the Prince Creek Formation contain the richest record of polar dinosaurs found anywhere in the world. Here we describe a new species of horned dinosaur, Pachyrhinosaurus perotorum that exhibits an apomorphic character in the frill, as well as a unique combination of other characters. Phylogenetic analysis of 16 taxa of ceratopsians failed to resolve relationships between P. perotorum and other Pachyrhinosaurus species (P. canadensis and P. lakustai). P. perotorum shares characters with each of the previously known species that are not present in the other, including very large nasal and supraorbital bosses that are nearly in contact and separated only by a narrow groove as in P. canadensis, and a rostral comb formed by the nasals and premaxillae as in P. lakustai. P. perotorum is the youngest centrosaurine known (70–69 Ma), and the locality that produced the taxon, the Kikak−Tegoseak Quarry, is close to the highest latitude for recovery of ceratopsid remains. Key words: Dinosauria, Centrosaurinae, Cretaceous, Prince Creek Formation, Kikak−Tegoseak Quarry, Arctic. Anthony R. Fiorillo [[email protected]] and Ronald S. Tykoski [[email protected]], Perot Museum of Nature and Science, 2201 N. Field Street, Dallas, TX 75202, USA. Received 4 April 2011, accepted 23 July 2011, available online 26 August 2011.
    [Show full text]
  • Horn Use in Triceratops (Dinosauria: Ceratopsidae): Testing Behavioral Hypotheses Using Scale Models
    Palaeontologia Electronica http://palaeo-electronica.org HORN USE IN TRICERATOPS (DINOSAURIA: CERATOPSIDAE): TESTING BEHAVIORAL HYPOTHESES USING SCALE MODELS Andrew A. Farke ABSTRACT Triceratops, a common chasmosaurine ceratopsid dinosaur from the Late Creta- ceous of North America, is known for its cranial ornamentation, including a single nasal horn and large, paired supraorbital horns. It is commonly surmised that Triceratops used its horns in intraspecific combat, but this hypothesis has not been rigorously tested. Scale models of Triceratops skulls were used to determine if it could physically lock horns as has been suggested. Three hypothetical horn locking positions were found, involving varying orientations of the combatants’ skulls. Based on these posi- tions, it was hypothesized that injuries caused by horns were especially likely in certain portions of the frill, jugals, and postorbital horncore tips. This corresponds to some pre- viously reported pathologies in chasmosaurine specimens. Uncertainties in this model- ing exercise center around variations in horn orientation, size, shape, and the possible existence of a keratinous supraorbital horncore sheath. Triceratops differs from modern horned mammals in its horn orientation, which suggests that if it engaged in intraspe- cific combat, its fighting style was quite different from these modern animals. During hypothetical horn locking in Triceratops, most of the force was directed against the medial and lateral surfaces of the horn cores. This has implications for future studies of ceratopsid cranial functional morphology, especially as related to horn architecture and the development of the frontal sinus complex. Andrew A. Farke. Department of Anatomical Sciences, Stony Brook University, Health Sciences Center, Stony Brook, New York, 11794-8081, USA.
    [Show full text]
  • Taxonomy, Cranial Morphology, and Relationships of Parrot-Beaked Dinosaurs (Ceratopsia: Psittacosaurus)
    2 Taxonomy, Cranial Morphology, and Relationships of Parrot-Beaked Dinosaurs (Ceratopsia: Psittacosaurus) PAUL C. SERENO in 1922, well-preserved fossils of the first parrot- (Coombs 1980, 1982). For many years, Osborn’s two brief beaked dinosaur were discovered in Early Cretaceous notes on P. mongoliensis (Osborn 1923, 1924) and a descrip- horizons in the Gobi Desert of Mongolia. Now referred to tion of P. sinensis (Young 1958) provided most of the informa- a single species, Psittacosaurus mongoliensis, these remains tion available on psittacosaur morphology. include a growth series from hatchlings to adults. In sub- Recent Work. Sereno (1987) provided an overview of psit- sequent years, 15 species have been added to the genus tacosaur morphology. Portions of this dissertation were pub- Psittacosaurus and a second genus, Hongshanosaurus, was lished, including the description of two new species (P. meiley- recently described, all from Early Cretaceous rocks in ingensis, P. xinjiangensis; Sereno and Zhao 1988; Sereno et al. Asia. Although the second genus and about one-half of 1988), the synonomy of several poorly known species (Sereno the species attributed to Psittacosaurus are potentially in- 1990a), and an overview of the morphology of the clade Psit- valid, Psittacosaurus remains the most species-rich dino- tacosauridae (Sereno 1990b). Although most of this overview saurian genus, with interspecific variation concentrated can be found in You and Dodson (2004), reference is made in the skull and dentition. This paper reviews evidence only to the original source (Sereno 1990b). differentiating the named genera and species of psit- Russian psittacosaurs, including a partial skull first reported tacosaurs, outlines major cranial changes in a growth se- by Rozhdestvensky (1955, 1960) at Shestakovo in Siberia, be- ries from hatchling to adult in Psittacosaurus came the subject of a dissertation by Xijin Zhao under his mongoliensis, and provides evidence of two species direction.
    [Show full text]
  • Body-Size Evolution in the Dinosauria
    8 Body-Size Evolution in the Dinosauria Matthew T. Carrano Introduction The evolution of body size and its influence on organismal biology have received scientific attention since the earliest decades of evolutionary study (e.g., Cope, 1887, 1896; Thompson, 1917). Both paleontologists and neontologists have attempted to determine correlations between body size and numerous aspects of life history, with the ultimate goal of docu- menting both the predictive and causal connections involved (LaBarbera, 1986, 1989). These studies have generated an appreciation for the thor- oughgoing interrelationships between body size and nearly every sig- nificant facet of organismal biology, including metabolism (Lindstedt & Calder, 1981; Schmidt-Nielsen, 1984; McNab, 1989), population ecology (Damuth, 1981; Juanes, 1986; Gittleman & Purvis, 1998), locomotion (Mc- Mahon, 1975; Biewener, 1989; Alexander, 1996), and reproduction (Alex- ander, 1996). An enduring focus of these studies has been Cope’s Rule, the notion that body size tends to increase over time within lineages (Kurtén, 1953; Stanley, 1973; Polly, 1998). Such an observation has been made regarding many different clades but has been examined specifically in only a few (MacFadden, 1986; Arnold et al., 1995; Jablonski, 1996, 1997; Trammer & Kaim, 1997, 1999; Alroy, 1998). The discordant results of such analyses have underscored two points: (1) Cope’s Rule does not apply universally to all groups; and (2) even when present, size increases in different clades may reflect very different underlying processes. Thus, the question, “does Cope’s Rule exist?” is better parsed into two questions: “to which groups does Cope’s Rule apply?” and “what process is responsible for it in each?” Several recent works (McShea, 1994, 2000; Jablonski, 1997; Alroy, 1998, 2000a, 2000b) have begun to address these more specific questions, attempting to quantify patterns of body-size evolution in a phylogenetic (rather than strictly temporal) context, as well as developing methods for interpreting the resultant patterns.
    [Show full text]
  • Bristle-Like Integumentary Structures at the Tail of the Horned Dinosaur Psittacosaurus
    Naturwissenschaften (2002) 89:361–365 DOI 10.1007/s00114-002-0339-6 SHORT COMMUNICATION Gerald Mayr · D. Stefan Peters · Gerhard Plodowski Olaf Vogel Bristle-like integumentary structures at the tail of the horned dinosaur Psittacosaurus Received: 20 December 2001 / Accepted: 26 May 2002 / Published online: 17 July 2002 © Springer-Verlag 2002 Abstract A specimen of the horned dinosaur Psittaco- in China has attracted much recent attention (Buffetaut saurus from the early Cretaceous of China is described 2001; Dalton 2001a, b; Stokstad 2001), because psittaco- in which the integument is extraordinarily well-pre- saurs rank among the Ceratopsia (horned dinosaurs), served. Most unusual is the presence of long bristle-like which occupy a phylogenetic position far removed from structures on the proximal part of tail. We interpret these theropod dinosaurs (Sereno 1990, 1999). Here we give a structures as cylindrical and possibly tubular epidermal first formal description of these structures. structures that were anchored deeply in the skin. They We are aware of the controversial debate concerning might have been used in display behavior and especially the legal ownership of this and other Chinese fossils if one assumes that they were colored, they may have (Dalton 2001a). However, arrangements concerning its had a signal function. At present, there is no convincing repatriation to China have not yet proved successful evidence which shows these structures to be homologous (Dalton 2001a), and this important specimen was ac- to the structurally different integumentary filaments of quired in order to prevent its sale into private hands and theropod dinosaurs. Independent of their homology, how- to ensure its availability for future scientific examination.
    [Show full text]
  • Brusatte Triceratops
    Media Inquiries: Kristin Elise Phillips, Department of Communications March 2009 212-496-3419; [email protected] www.amnh.org _____________________________________________________________________________ WAS TRICERATOPS A SOCIAL ANIMAL? YES, ACCORDING TO A NEW FOSSIL DISCOVERY IN MONTANA’S HOMER SITE Until now, Triceratops was thought to be unusual among its ceratopsid relatives. While many ceratopsids—a common group of herbivorous dinosaurs that lived toward the end of the Cretaceous—have been found in enormous bonebed deposits of multiple individuals, all known Triceratops (over 50 in total) fossils have been solitary individuals. But a new discovery of a jumble of at least three juveniles the badlands of the north-central United States suggests that the three-horned dinosaurs were not only social animals, but may have exhibited unique gregarious groupings of juveniles. “This is very thrilling,” says Stephen Brusatte, an affiliate of the American Museum of Natural History and a doctoral student at Columbia University. “We can say something about how these dinosaurs lived. Interestingly, what we’ve found seems to be a larger pattern among many dinosaurs that juveniles lived and traveled together in groups.” In 2005, Brusatte and colleagues found and excavated a site that contained multiple Triceratops juveniles in 66-million-year-old rocks in southeastern Montana. The geological evidence suggests that at least three juveniles were deposited at the same time by a localized flood, and this suggests that they were probably living together when disaster struck. This find indicates that Triceratops juveniles congregated in small herds, a social behavior increasingly identified in other dinosaur groups, such as Psittacosaurus, a small cousin of Triceratops that lived in Asia.
    [Show full text]
  • A Possible Ceratopsid Tooth from the Upper Cretaceous of Kyushu, Japan
    Bull. Natl. Mus. Nat. Sci., Ser. C, 42, pp. 29–34, December 22, 2016 A possible ceratopsid tooth from the Upper Cretaceous of Kyushu, Japan Makoto Manabe1, Takanobu Tsuihiji2, Yuka Miyake3 and Toshifumi Komatsu4 1 Department of Geology and Paleontology, National Museum of Nature and Science, 4–1–1 Amakubo, Tsukuba, Ibaraki 305–0005, Japan 2 Department of Earth and Planetary Science, The University of Tokyo, 7–3–1 Hongo, Bunkyo-ku, Tokyo 113–0033, Japan 3 Satsumasendai City Board of Education, 1457–10 Imuta, Kashima, Satsumasendai, Kagoshima 896–1392, Japan 4 Faculty of Advanced Science and Technology, Kumamoto University, 2–39–1 Kurokami, Chuo-ku, Kumamoto 860–8555, Japan Abstract A fragmentary tooth is reported from the Campanian section of the Upper Cretaceous Himenoura Group on Shimokoshikishima Island of Kyushu, Japan. The tooth specimen is identi- fied as the medial root of a ceratopsid dinosaur. If this identification is correct, it represents a rare example of the clade in Asia. Key words : Ceratopsidae, Dinosauria, Himenoura Group, Campanian, Kyushu, Japan Introduction North America until Xu et al. (2010) described Sinoceratops zhuchengensis from the Upper Cre- Ceratopsians were one of the most successful taceous of China, demonstrating the presence of clades of dinosaurs in North America and Asia this clade in Asia. However, remains of ceratop- during the Cretaceous Period (e.g., Dodson et al., sids are still very scarce in Asia with S. zhuchen- 2004; You and Dodson, 2004). Ceratopsians, gensis being the only definite Asian ceratopsid. especially ceratopsids, are characterized by In the present study, a fragmentary element derived and diversified characters especially in found from the Campanian section of the Hime- the skull such as the distinctive frill, horns and noura Group on Shimokoshikishima Island in beak (Dodson, 1996).
    [Show full text]
  • HISTORY of the CERATOPSIAN DINOSAUR TRICERATOPS in the Science Museum of Minnesota 1960 – Present by Bruce R
    HISTORY OF THE CERATOPSIAN DINOSAUR TRICERATOPS In The Science Museum of Minnesota 1960 – Present by Bruce R. Erickson MONOGRAPH VOLUME 12: PALEONTOLOGY Published by THE SCIENCE MUSEUM OF MINNESOTA SAINT PAUL, MINNESOTA 55102 HISTORY OF THE CERATOPSIAN DINOSAUR TRICERATOPS In The Science Museum of Minnesota 1960 – Present Bruce R. Erickson Fitzpatrick Chair of Paleontology MONOGRAPH VOLUME 12: PALEONTOLOGY The Science Museum of Minnesota 120 West Kellogg Blvd. Saint Paul, Minnesota 55102 USA. July 28, 2017 Frontispiece: First season at Triceratops quarry 1960. CONTENTS INTRODUCTION .............................................................5 COLLECTING TRICERATOPS 1960-1964 FIELD WORK ............................5 ABOUT THE MOUNTED SKELETON 1964-1965 ..................................18 ABOUT THE BRAIN OF TRICERATOPS. 19 EPILOGUE ..................................................................22 OTHER FINDS, NOTES, and VIEWS (Figs. 12-28) ..................................24 From the Triceratops Expeditions 1959-1964 ACKNOWLEDGMENTS .......................................................34 REFERENCES ...............................................................34 APPENDIX I ................................................................36 APPENDIX II ................................................................36 MONOGRAPH VOLUME 12: PALEONTOLOGY International Standard Book Number: 911338-92-6 SCIENCE MUSEUM OF MINNESOTA MONOGRAPH VOL. 12 HISTORY OF THE CERATOPSIAN DINOSAUR TRICERATOPS In The Science Museum of Minnesota 1960
    [Show full text]