THE FOSSIL RECORD of MESOZOIC MAMMALS in CHINA by Zhang Fakui
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Evolution of the Patellar Sesamoid Bone in Mammals
A peer-reviewed version of this preprint was published in PeerJ on 21 March 2017. View the peer-reviewed version (peerj.com/articles/3103), which is the preferred citable publication unless you specifically need to cite this preprint. Samuels ME, Regnault S, Hutchinson JR. 2017. Evolution of the patellar sesamoid bone in mammals. PeerJ 5:e3103 https://doi.org/10.7717/peerj.3103 Evolution of the patellar sesamoid bone in mammals Mark E Samuels 1, 2 , Sophie Regnault 3 , John R Hutchinson Corresp. 3 1 Department of Medicine, University of Montreal, Montreal, Quebec, Canada 2 Centre de Recherche du CHU Ste-Justine, Montreal, Quebec, Canada 3 Structure & Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hatfield, Hertfordshire, United Kingdom Corresponding Author: John R Hutchinson Email address: [email protected] The patella is a sesamoid bone located in the major extensor tendon of the knee joint, in the hindlimb of many tetrapods. Although numerous aspects of knee morphology are ancient and conserved among most tetrapods, the evolutionary occurrence of an ossified patella is highly variable. Among extant (crown clade) groups it is found in most birds, most lizards, the monotreme mammals and almost all placental mammals, but it is absent in most marsupial mammals as well as many reptiles. Here we integrate data from the literature and first-hand studies of fossil and recent skeletal remains to reconstruct the evolution of the mammalian patella. We infer that bony patellae most likely evolved between four to six times in crown group Mammalia: in monotremes, in the extinct multituberculates, in one or more stem-mammal genera outside of therian or eutherian mammals, and up to three times in therian mammals. -
Marsupials As Models for Research
CSIRO PUBLISHING Introduction www.publish.csiro.au/journals/ajz Australian Journal of Zoology, 2006, 54, 137–138 Marsupials as models for research Lynne SelwoodA,B and Graeme CoulsonA ADepartment of Zoology, The University of Melbourne, Vic. 3010, Australia. BCorresponding author. Email: [email protected] Marsupials are worth studying for their intrinsic value alone. rather than by trying to determine what happens when the They are one of the three major extant mammal types, conceptuses are implanted in the uterus, as in the mouse. The Prototheria (monotremes), Metatheria (marsupials) and Renfree and Shaw group has skilfully exploited this in the Eutheria, and have provided important information about the tammar wallaby, and provided further experimental advan- evolution of mammals. They represent the major mammalian tages by developing techniques for gonad sex reversal and group on the Australian continent, and their study makes an female reproductive tract sex reversal in the neonates important contribution to our natural heritage. Such studies (Renfree et al. 2006). Using marsupials, the development of are necessary in order to stem the further loss of marsupial the scrotum, mammary glands, pouch and processus vagi- diversity due to extinction of species. In addition, the study nalis are shown to be sexually dimorphic before the testis of marsupial species has provided new insights into old prob- differentiates, and hence are independent of testicular hor- lems, because of their value as models to study a variety of mones. These studies have been extended into the molecular totally different fields. level. The study of marsupials can be seen as an example of the Studies on life history strategies of Antechinus showed importance of basic research. -
Recent Advances in Studies on Mesozoic and Paleogene Mammals in China
Vol.24 No.2 2010 Paleomammalogy Recent Advances in Studies on Mesozoic and Paleogene Mammals in China WANG Yuanqing* and NI Xijun Institute of Vertebrate Paleontology and Paleoanthropology, CAS, Beijing 10004, China ike in other fields of paleontology, research in from the articular of the lower jaw and the quadrate of the paleomammalogy mainly falls into two aspects. cranium following the process of reduction and detachment LOne is related to the biological nature of fossil from the reptilian mandible, are new elements of the bony mammals, such as their systematics, origin, evolution, chain in the mammalian middle ear. The appearance of phylogenetic relationships, transformation of key features mammalian middle ear allows mammals to hear the sound and paleobiogeography, and the other is related to the of higher frequencies than reptiles do. Generally speaking, geological context, involving biostratigraphy, biochronology, a widely accepted hypothesis is that mammals originated faunal turnover and its relations to the global and regional from a certain extinct reptilian group. The formation and environmental changes. In the last decade, a number of development of the definitive mammalian middle ear well-preserved mammalian specimens were collected from (DMME) has thus become one of the key issues in the study different localities around the country. Such discoveries have of mammalian evolution and has drawn the attention from provided significant information for understanding the early many researchers for many years. evolution of mammals and reconstructing the phylogeny of Developmental biological studies have proven the early mammals. function of the Meckel’s cartilage and its relationship to Studies of Chinese Mesozoic mammals achieved the ear ossicles during the development of mammalian remarkable progress in the past several years. -
Constraints on the Timescale of Animal Evolutionary History
Palaeontologia Electronica palaeo-electronica.org Constraints on the timescale of animal evolutionary history Michael J. Benton, Philip C.J. Donoghue, Robert J. Asher, Matt Friedman, Thomas J. Near, and Jakob Vinther ABSTRACT Dating the tree of life is a core endeavor in evolutionary biology. Rates of evolution are fundamental to nearly every evolutionary model and process. Rates need dates. There is much debate on the most appropriate and reasonable ways in which to date the tree of life, and recent work has highlighted some confusions and complexities that can be avoided. Whether phylogenetic trees are dated after they have been estab- lished, or as part of the process of tree finding, practitioners need to know which cali- brations to use. We emphasize the importance of identifying crown (not stem) fossils, levels of confidence in their attribution to the crown, current chronostratigraphic preci- sion, the primacy of the host geological formation and asymmetric confidence intervals. Here we present calibrations for 88 key nodes across the phylogeny of animals, rang- ing from the root of Metazoa to the last common ancestor of Homo sapiens. Close attention to detail is constantly required: for example, the classic bird-mammal date (base of crown Amniota) has often been given as 310-315 Ma; the 2014 international time scale indicates a minimum age of 318 Ma. Michael J. Benton. School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, U.K. [email protected] Philip C.J. Donoghue. School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, U.K. [email protected] Robert J. -
0 Introduction
Cambridge University Press 978-0-521-78117-6 - Evolution of Tertiary Mammals of North America, Volume 2: Small Mammals, Xenarthrans, and Marine Mammals Christine M. Janis, Gregg F. Gunnell and Mark D. Uhen Excerpt More information 0 Introduction christine m. janis,1 gregg f. gunnell2 and mark d. uhen3 1Brown University, Providence, RI, USA 2Museum of Paleontology, University of Michigan, Ann Arbor, MI, USA 3Smithsonian Institution, Washington, DC, USA AIMS OF VOLUME 2 the chapter are presented according to a standardized format, and the institutional abbreviations have also been standardized and are This enterprise was originally conceived of as a single volume. How- listed in an appendix (Appendix III). ever, after a span of 10 years from its original conception, the current senior editor (Christine Janis), and the then junior editors (Kathleen Scott and Louis Jacobs) realized that it would be more realistic THE STANDARDIZED LAYOUT OF EACH CHAPTER to proceed with chapters then in hand, which could more or less be assembled into the conceptually useful, if taxonomically para- The chapters are laid out in a similar fashion to those in Volume 1. phyletic, rubric of “Terrestrial Carnivores and Ungulates” (Janis, The contributors were requested to adhere to a common layout for Scott, and Jacobs, 1998). This in part reflected the chapters that had each chapter, in order to provide uniform information throughout been assembled to date, although it should be noted that some of the book. The “Introduction” for each chapter introduces the group. the chapters in this current volume, most notably those by Darryl The “Defining features” section lays out the basic cranial, dental, Domning on sirenians and desmostylians, were among the first ones and postcranial features of the taxon. -
The Oldest Platypus and Its Bearing on Divergence Timing of the Platypus and Echidna Clades
The oldest platypus and its bearing on divergence timing of the platypus and echidna clades Timothy Rowe*†, Thomas H. Rich‡§, Patricia Vickers-Rich§, Mark Springer¶, and Michael O. Woodburneʈ *Jackson School of Geosciences, University of Texas, C1100, Austin, TX 78712; ‡Museum Victoria, PO Box 666, Melbourne, Victoria 3001, Australia; §School of Geosciences, PO Box 28E, Monash University, Victoria 3800, Australia; ¶Department of Biology, University of California, Riverside, CA 92521; and ʈDepartment of Geology, Museum of Northern Arizona, Flagstaff, AZ 86001 Edited by David B. Wake, University of California, Berkeley, CA, and approved October 31, 2007 (received for review July 7, 2007) Monotremes have left a poor fossil record, and paleontology has broadly affect our understanding of early mammalian history, been virtually mute during two decades of discussion about with special implications for molecular clock estimates of basal molecular clock estimates of the timing of divergence between the divergence times. platypus and echidna clades. We describe evidence from high- Monotremata today comprises five species that form two resolution x-ray computed tomography indicating that Teinolo- distinct clades (16). The echidna clade includes one short-beaked phos, an Early Cretaceous fossil from Australia’s Flat Rocks locality species (Tachyglossus aculeatus; Australia and surrounding is- (121–112.5 Ma), lies within the crown clade Monotremata, as a lands) and three long-beaked species (Zaglossus bruijni, Z. basal platypus. Strict molecular clock estimates of the divergence bartoni, and Z. attenboroughi, all from New Guinea). The between platypus and echidnas range from 17 to 80 Ma, but platypus clade includes only Ornithorhynchus anatinus (Austra- Teinolophos suggests that the two monotreme clades were al- lia, Tasmania). -
Mammals from the Mesozoic of Mongolia
Mammals from the Mesozoic of Mongolia Introduction and Simpson (1926) dcscrihed these as placental (eutherian) insectivores. 'l'he deltathcroids originally Mongolia produces one of the world's most extraordi- included with the insectivores, more recently have narily preserved assemblages of hlesozoic ma~nmals. t)een assigned to the Metatheria (Kielan-Jaworowska Unlike fossils at most Mesozoic sites, Inany of these and Nesov, 1990). For ahout 40 years these were the remains are skulls, and in some cases these are asso- only Mesozoic ~nanimalsknown from Mongolia. ciated with postcranial skeletons. Ry contrast, 'I'he next discoveries in Mongolia were made by the Mesozoic mammals at well-known sites in North Polish-Mongolian Palaeontological Expeditions America and other continents have produced less (1963-1971) initially led by Naydin Dovchin, then by complete material, usually incomplete jaws with den- Rinchen Barsbold on the Mongolian side, and Zofia titions, or isolated teeth. In addition to the rich Kielan-Jaworowska on the Polish side, Kazi~nierz samples of skulls and skeletons representing Late Koualski led the expedition in 1964. Late Cretaceous Cretaceous mam~nals,certain localities in Mongolia ma~nmalswere collected in three Gohi Desert regions: are also known for less well preserved, but important, Bayan Zag (Djadokhta Formation), Nenlegt and remains of Early Cretaceous mammals. The mammals Khulsan in the Nemegt Valley (Baruungoyot from hoth Early and Late Cretaceous intervals have Formation), and llcrmiin 'ISav, south-\vest of the increased our understanding of diversification and Neniegt Valley, in the Red beds of Hermiin 'rsav, morphologic variation in archaic mammals. which have heen regarded as a stratigraphic ecluivalent Potentially this new information has hearing on the of the Baruungoyot Formation (Gradzinslti r't crl., phylogenetic relationships among major branches of 1977). -
Femur of a Morganucodontid Mammal from the Middle Jurassic of Central Russia
Femur of a morganucodontid mammal from the Middle Jurassic of Central Russia PETR P. GAMBARYAN and ALEXANDER 0.AVERIANOV Gambaryan, P.P. & Averianov, A.O. 2001. Femur of a morganucodontid mammal from the Middle Jurassic of Central Russia. -Acta Palaeontologica Polonica 46,1,99-112. We describe a nearly complete mammalian femur from the Middle Jurassic (upper Bathonian) from Peski quarry, situated some 100 km south east of Moscow, central Rus- sia. It is similar to the femora of Morganucodontidae in having a globular femoral head, separated from the greater trochanter and reflected dorsally, fovea capitis present, both trochanters triangular and located on the same plane, distal end flat, mediolaterally expanded, and somewhat bent ventrally, and in the shape and proportions of distal condyles. It is referred to as Morganucodontidae gen. et sp. indet. It is the first representa- tive of this group of mammals in Eastern Europe from the third Mesozoic mammal local- ity discovered in Russia. Exquisite preservation of the bone surface allowed us to recon- struct partial hind limb musculature. We reconstruct m. iliopsoas as inserting on the ridge, which starts at the lesser trochanter and extends along the medial femoral margin for more than half of the femur length. On this basis we conclude that the mode of loco- motion of the Peski morganucodontid was similar to that of modern echidnas. During the propulsive phase the femur did not retract and the step elongation was provided by pronation of the femur. Key words : Mammalia, Morganucodontidae, femur, anatomy, locomotion, Jurassic, Russia. Petr P. Gambaryan [[email protected]] and Alexander 0. -
AMERICAN MUSEUM NOVITATES Published by Number 330 Thz Auerican Museum of NAITURAL HISTORY October 30, 1928 New York City
AMERICAN MUSEUM NOVITATES Published by Number 330 THz AuERicAN MusEUM oF NAITURAL HISTORY October 30, 1928 New York City 56.9,33 (117:51.7) AFFINITIES OF THE MONGOLIAN CRETACEOUS INSECTIVORES' BY GEORGE GAYLORD SIMPSON The unique series of Mesozoic mammal remains found by the Third Asiatic Expedition in Mongolia has now been completely de- scribed in a series of three papers.2 The affinities of the one known multituberculate, Djadochtatherium matthewi, were as thoroughly discussed as the material warrants in the first paper, and no additional remarks seem necessary. The relationships of the more important insectivores, however, were only briefly discussed in the second paper and a review of the evidence, especially including the important new details given in the third paper, suggests some modification and amplification of the views already presented. Not only are these mammal remains by far the most complete ever discovered in the Mesozoic, but they also occupy a very strategic position in time and in space which makes close scrutiny of their relationships essential. In time they occur in the Cretaceous, when, according to theories formed before their discovery and based largely on early Tertiary mammals, the differentiation of the placental orders should be in progress and not yet far advanced. In space they occur in Central Asia in or near the region which a number of students, especially Osborn and Matthew, have considered as an important center of radiation and probably the very one whence came the groups of mammals which appear to have entered North America and Europe suddenly at the beginning of the Tertiary and which must have been undergoing an important deployment during upper Cretaceous time. -
Mammals at Woodland Park Zoo Pre-Visit Information
Mammals at Woodland Park Zoo Pre-visit Information If you are planning a zoo field trip and wish to have your students focus on mammals during their visit, this pre- visit sheet can help them get the most out of their time at the zoo. We have put together an overview of key concepts related to mammals, a list of basic vocabulary words, and a checklist of mammal species at Woodland Park Zoo. Knowledge and understanding of these main ideas will enhance your students’ zoo visit. OVERVIEW: There are over 5,000 species of mammals currently identified worldwide, inhabiting a number of different biomes and exhibiting a range of adaptations. Woodland Park Zoo exhibits a wide variety of mammal species (see attached checklist) in several different areas of the zoo. A mammal field trip to the zoo could focus on the characteristics of mammals (see “Concepts” below), comparing/contrasting different mammals or learning about biomes and observing the physical characteristics of mammals in different biomes. CONCEPTS: Mammals share the following physical characteristics: • Fur or hair • Endothermic, often called warm-blooded. Endothermic animals maintain a constant internal body temperature rather than adjusting to the temperature of their surroundings as ectothermic animals (such as reptiles and amphibians) do. • Mammary glands, which are used to feed milk to young Mammals, like all plants and animals, have five basic needs to survive—food, water, shelter, air and space. They inhabit every continent on the planet and range in size from Kitti’s hog-nosed bat (also called bumblebee bat) at 0.07 ounces (2 grams) to the blue whale at 100 tons (approximately 90,000 kilograms). -
The Origin of Mammals: a Study of Some Important Fossils
CEN Tech. J., vol. 7(2), 1993, pp. 122–139 The Origin of Mammals: A Study of Some Important Fossils A. W. MEHLERT ABSTRACT For many years evolutionists have pointed to the alleged transition of reptiles to mammals as being the best example of the natural origin of a major taxon. At first sight such claims appear to have considerable justification, but when the fossil evidence is closely examined it can be shown that there are some grave deficiencies, and the claim is not only factually unproved but also contains a number of dubious assumptions. It is therefore proposed to subject certain of the key fossils to more scrutiny. INTRODUCTION AND BRIEF OVERVIEW therapsids of later Permian and Triassic ‘times’. It is supposedly within the order Therapsida (suborder In 1966 Olson wrote, Theriodontia), that we find the subgroups to which the ‘The reptilian-mammalian transition has by far the immediate ancestors of mammals are assigned (see Table finest record of showing the origin of a new 24). class.’ (Emphasis added.)1 Almost all authorities are convinced that the immediate Kemp in 1982 had the same view.2 If it can be shown that reptilian ancestors of the early mammals are to be found in such a claim is not as strong as Olson and Kemp believe, the infraorders Cynodontia, Tritylodontia and Ictidosauria, then by implication, the evolutionary origin of all other although all six theriodont subgroups contain fossils which classes in the animal and plant kingdoms must be even more appear to bear at least some mammalian-like features. doubtful. -
Early Cretaceous Amphilestid ('Triconodont') Mammals from Mongolia
Early Cretaceous amphilestid ('triconodont') mammals from Mongolia ZOFIAKIELAN-JAWOROWSKA and DEMBERLYIN DASHZEVEG Kielan-Jaworowską Z. &Daslueveg, D. 1998. Early Cretaceous amphilestid (.tricono- dont') mammals from Mongotia. - Acta Pal.aeontol.ogicaPolonica,43,3, 413438. Asmall collection of ?Aptianor ?Albian amphilestid('triconodont') mammals consisting of incomplete dentaries and maxillae with teeth, from the Khoboor localiĘ Guchin Us counĘ in Mongolia, is described. Grchinodon Troftmov' 1978 is regarded a junior subjective synonym of GobiconodonTroftmov, 1978. Heavier wear of the molariforms M3 andM4than of themore anteriorone-M2 in Gobiconodonborissiaki gives indirect evidence formolariformreplacement in this taxon. The interlocking mechanismbetween lower molariforms n Gobiconodon is of the pattern seen in Kuchneotherium and Ttnodon. The ińterlocking mechanism and the type of occlusion ally Amphilestidae with Kuehneotheriidae, from which they differ in having lower molariforms with main cusps aligned and the dentary-squamosal jaw joint (double jaw joint in Kuehneotheńdae). The main cusps in upper molariforms M3-M5 of Gobiconodon, however, show incipient tńangular arrangement. The paper gives some support to Mills' idea on the therian affinities of the Amphilestidae, although it cannot be excluded that the characters that unite the two groups developed in parallel. Because of scanty material and arnbiguĘ we assign the Amphilestidae to order incertae sedis. Key words : Mammali4 .triconodonts', Amphilestidae, Kuehneotheriidae, Early Cretaceous, Mongolia. Zofia Kiel,an-Jaworowska [zkielnn@twarda,pan.pl], InsĘtut Paleobiologii PAN, ul. Twarda 5 I /5 5, PL-00-8 I 8 Warszawa, Poland. DemberĘin Dash7eveg, Geological Institute, Mongolian Academy of Sciences, Ulan Bator, Mongolia. Introduction Beliajeva et al. (1974) reportedthe discovery of Early Cretaceous mammals at the Khoboor locality (referred to also sometimes as Khovboor), in the Guchin Us Soinon (County), Gobi Desert, Mongolia.