Ears About Ancient Mammals
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The Ear in Mammal-Like Reptiles and Early Mammals
Acta Palaeontologica Polonica Vol. 28, No. 1-2 pp, 147-158 Warszawa, 1983 Second Symposium on Mesozoic T erre stial Ecosystems, Jadwisin 1981 KENNETH A. KERMACK and FRANCES MUSSETT THE EAR IN MAMMAL-LIKE REPTILES AND EARLY MAMMALS KERMACK, K . A. a nd MUSS ETT, F.: The ear in mammal-like r eptiles an d early mammals. Acta Palaeont. P olonica , 28, 1-2, 147-158, 1983. Th e early m embers of the Theropsida lacked a tympanic membrane. In the later theropslds, the Therapsid a, a tym p an ic membrane develop ed from thc skin on the lateral side of th e lower jaw. The tympanum is not homologous In the Therapsida and ' t he Sauropslda. The ther apsid ea r w as a poor receiver of airborne sound, both In hi gh frequency r esp onse and In the r ange of frequencies encompassed. With the radiation of the Sauropsida in the Triassic the large therapsids became extinct, the small therap si ds evolv ed In to the mammal s and became nocturnal. High frequency hearin g w as essen tial for the nocturn al mode of life; quadrate and arttcutar became diss ociated from the jaw hinge to become the m ammali an au di tory ossi cles . I n the Theria the cochlea became coil ed. The spiral cochlea could n ot have existed until there w as a middle ear w ith the n ec essary h ig h f re q uency r esp onse. This m ay n ot have been until the Cretace ous. -
The Intramandibular Joint in Girella: a Mechanism for Increased Force Production?
JOURNAL OF MORPHOLOGY 271:271–279 (2010) The Intramandibular Joint in Girella: A Mechanism for Increased Force Production? Lara A. Ferry-Graham1,3* and Nicolai Konow2 1California State University, Moss Landing Marine Labs, Moss Landing, California 95039 2Brown University, Ecology and Evolutionary Biology, Providence, Box G-B204, Rhode Island 02912 3CEAZA, Centro de Estudios Avanzados de Zonas Aridas (Center for Advanced Studies in Arid Zones), Universidad Cato´lica del Norte. Box 599, Benavente 980, La Serena, Chile ABSTRACT Intramandibular joints (IMJ) are novel Bellwood, 2002). This is likely due to the forces articulations between bony elements of the lower jaw required for obtaining food items many of which are that have evolved independently in multiple fish line- either tough or firmly attached to the substrate ages and are typically associated with biting herbivory. (Alfaro et al., 2001). In several reef fish lineages, This novel joint is hypothesized to function by augment- aspects of the feeding apparatus have been radically ing oral jaw expansion during mouth opening, which would increase contact between the tooth-bearing area altered for force production, either via hypertro- of the jaws and algal substratum during feeding, result- phied or via structurally altered musculature (Friel ing in more effective food removal from the substrate. and Wainwright, 1997), modified muscle attach- Currently, it is not understood if increased flexibility in ments (Vial and Ojeda, 1990; Konow and Bellwood, a double-jointed mandible also results in increased force 2005), or increased suturing and/or reinforcement generation during herbivorous biting and/or scraping. of bony elements and dentition (Tedman, 1980; Therefore, we selected the herbivore Girella laevifrons Streelman et al., 2002; Bellwood et al., 2003). -
The Skull O Neurocranium, Form and Function O Dermatocranium, Form
Lesson 15 ◊ Lesson Outline: ♦ The Skull o Neurocranium, Form and Function o Dermatocranium, Form and Function o Splanchnocranium, Form and Function • Evolution and Design of Jaws • Fate of the Splanchnocranium ♦ Trends ◊ Objectives: At the end of this lesson, you should be able to: ♦ Describe the structure and function of the neurocranium ♦ Describe the structure and function of the dermatocranium ♦ Describe the origin of the splanchnocranium and discuss the various structures that have evolved from it. ♦ Describe the structure and function of the various structures that have been derived from the splanchnocranium ♦ Discuss various types of jaw suspension and the significance of the differences in each type ◊ References: ♦ Chapter: 9: 162-198 ◊ Reading for Next Lesson: ♦ Chapter: 9: 162-198 The Skull: From an anatomical perspective, the skull is composed of three parts based on the origins of the various components that make up the final product. These are the: Neurocranium (Chondocranium) Dermatocranium Splanchnocranium Each part is distinguished by its ontogenetic and phylogenetic origins although all three work together to produce the skull. The first two are considered part of the Cranial Skeleton. The latter is considered as a separate Visceral Skeleton in our textbook. Many other morphologists include the visceral skeleton as part of the cranial skeleton. This is a complex group of elements that are derived from the ancestral skeleton of the branchial arches and that ultimately gives rise to the jaws and the skeleton of the gill -
Mammalogy Lecture 2 - Origin of Mammals I
Mammalogy Lecture 2 - Origin of Mammals I. There are three major living (extant) groups of mammals A. Monotremes - egg laying mammals B. Metatherians - marsupial mammals C. Eutherians - Placental mammals These are related by the following evolutionary tree or phylogeny Monotremes Metatherians (Marsupials) Eutherians (Placentals) Node - Divergence Event Branch - Common Ancestor Marsupials and placentals share an ancestor not shared by monotremes. II. A. In order to understand the origin of mammals, we have to look farther back, into the Paleozoic (350 MYA), and look at relationships among the tetrapod vertebrates. So we’ll start by going deeper in time, and work our way back up to this level in the phylogeny. Amp hibians Mamm als Tur tles Squ amates Crocodylians Dino1 Birds Dino 2 Synaps ida Stem Rep tiles - Captor hino mo rp hs Am n ion Trans ition to land We can mark evolutionary changes along this phylogeny; the evolution of limbs, the evolution of the amnion, etc. It’s this lineage labeled Synapsida that we’ll examine in order to understand the origin of mammals. We need to understand the situation just prior to this in the “stem reptiles,” the ancestors to mammals, birds, turtles, and other reptiles. Captorhinomorphs. B. In the Carboniferous, ca. 350 MYBP, the captorhinomorphs evolved, and the synapsid lineage diverged from the stem reptiles 30 MY later 320 MYA, and it’s this lineage that will eventually lead the modern mammals. Synapsid - “together arch” describes a skull condition that is unique to this lineage. The word “synapsid” is also used to refer to the group of organisms that exhibit this condition. -
Middle Ear Structures in the Permian Glanosuchus Sp. (Therocephalia, Therapsida), Based on Thin Sections
Mitt. Mus. Nat.kd. Berl., Geowiss. Reihe 5 (2002) 309-318 10.11.2002 Middle ear structures in the Permian Glanosuchus sp. (Therocephalia, Therapsida), based on thin sections Wolfgang Maierl & Juri van den Heever2 With 14 figures Abstract Transverse sections of the skull of the Permian therocephalian Glunosuchus sp. were studied with regard to the structures of the middle ear region. It is generally accepted that most of the skeletal elements of the mammalian middle ear are derived from the postdentary bones of the lower jaw. During synapsid evolution there is a gradual transition from a primitive amniote condition to derived mammalian condition; the latter is characterized by the decoupling of the remaining middle ear elements (angular, prearticular, articular) from the dentary, which forms a secondary jaw articulation with the squamosal. Morgunuco- don from the Triassic-Jurassic boundary represents an evolutionary stage, where both jaw articulations are present in a coaxial position and where the primary joint is a Pready a fully effective sound transmitter. Therocephalians are considered to be a good representation of the transitory state of this evolutionary process; this may be especially true for primitive taxa such as the lycosuchid Glunosuchus, whose anatomy may represent the “groundplan” (ancestral morphotype) of Lower to Middle Permian eutheriodonts. We studied a complete sectional series of a young specimen of Glunosuchus sp. prepared using the grind-and peel-technique. This showed that the reflected lamina of Glunosuchus is in major parts an extremely thin bony plate, which is best interpreted as a sound-receiving element overlying an air-filled recessus of the pharynx. -
Jaw Suspension
JAW SUSPENSION Jaw suspension means attachment of the lower jaw with the upper jaw or the skull for efficient biting and chewing. There are different ways in which these attachments are attained depending upon the modifications in visceral arches in vertebrates. AMPHISTYLIC In primitive elasmobranchs there is no modification of visceral arches and they are made of cartilage. Pterygoqadrate makes the upper jaw and meckel’s cartilage makes lower jaw and they are highly flexible. Hyoid arch is also unchanged. Lower jaw is attached to both pterygoqadrate and hyoid arch and hence it is called amphistylic. AUTODIASTYLIC Upper jaw is attached with the skull and lower jaw is directly attached to the upper jaw. The second arch is a branchial arch and does not take part in jaw suspension. HYOSTYLIC In modern sharks, lower jaw is attached to pterygoquadrate which is in turn attached to hyomandibular cartilage of the 2nd arch. It is the hyoid arch which braces the jaw by ligament attachment and hence it is called hyostylic. HYOSTYLIC (=METHYSTYLIC) In bony fishes pterygoquadrate is broken into epipterygoid, metapterygoid and quadrate, which become part of the skull. Meckel’s cartilage is modified as articular bone of the lower jaw, through which the lower jaw articulates with quadrate and then with symplectic bone of the hyoid arch to the skull. This is a modified hyostylic jaw suspension that is more advanced. AUTOSTYLIC (=AUTOSYSTYLIC) Pterygoquadrate is modified to form epipterygoid and quadrate, the latter braces the lower jaw with the skull. Hyomandibular of the second arch transforms into columella bone of the middle ear cavity and hence not available for jaw suspension. -
Joints Chapter 8
Chapter 8 Joints Alessandro Castriota-Scanderbeg, M.D. Joints develop secondarily in the mesenchyme com- Joint Contracture, Joint Stiffness prised between the developing ends of two adjacent bones (mesenchymal interpose) at about 5 1/2 weeks. ᭤ [Limitation (loss) of (active and passive) The mesenchyme is converted to form fibrous tissue, joint motion] hyaline cartilage, or fibrocartilage, depending on whether the developing joint is a fibrous joint, a syn- The issue discussed in the current section encom- chondrosis, or a symphysis, respectively.At the site of passes a heterogeneous group of conditions, both in- a synovial joint, while the primitive mesenchyme of herited and acquired, isolated and associated with the interzone undergoes liquefaction and cavitation, syndromic and nonsyndromic malformation spec- giving rise to the articular cavity, its peripheral con- tra, localized to one joint and generalized. An intro- densation results in formation of the joint capsule duction to the contractural abnormalities developing (Resnick et al.1995).This process is completed by ap- after birth is first provided, followed by a discussion proximately 7 weeks of fetal age, and by 8 weeks of the congenital forms, which represent the main fo- movements of the limbs about the joint are appear- cus of the section. ing. Motion is essential for the normal development Flexion contracture and joint stiffness may occur of joints and contiguous structures. As discussed in as late manifestations of conditions causing joint more detail in the following pages, congenital limita- and/or surrounding tissue infiltration (sarcoidosis, tion or loss of joint function may be caused by factors amyloidosis), hemorrhage (trauma, hemophilia), or that either are intrinsic to the joint, or are extrinsic inflammation (rheumatoid arthritis, systemic lupus but inhibit fetal movements. -
Furry Folk: Synapsids and Mammals
FURRY FOLK: SYNAPSIDS AND MAMMALS Of all the great transitions between major structural grades within vertebrates, the transition from basal amniotes to basal mammals is represented by the most complete and continuous fossil record, extending from the Middle Pennsylvanian to the Late Triassic and spanning some 75 to 100 million years. —James Hopson, “Synapsid evolution and the radiation of non-eutherian mammals,” 1994 At the very beginning of their history, amniotes split into two lineages, the synapsids and the reptiles. Traditionally, the earliest synapsids have been called the “mammal-like reptiles,” but this is a misnomer. The earliest synapsids had nothing to do with reptiles as the term is normally used (referring to the living reptiles and their extinct relatives). Early synapsids are “reptilian” only in the sense that they initially retained a lot of primitive amniote characters. Part of the reason for the persistence of this archaic usage is the precladistic view that the synapsids are descended from “anapsid” reptiles, so they are also reptiles. In fact, a lot of the “anapsids” of the Carboniferous, such as Hylonomus, which once had been postulated as ancestral to synapsids, are actually derived members of the diapsids (Gauthier, 1994). Furthermore, the earliest reptiles (Westlothiana from the Early Carboniferous) and the earliest synapsids (Protoclepsydrops from the Early Carboniferous and Archaeothyris from the Middle Carboniferous) are equally ancient, showing that their lineages diverged at the beginning of the Carboniferous, rather than synapsids evolving from the “anapsids.” For all these reasons, it is no longer appropriate to use the term “mammal-like reptiles.” If one must use a nontaxonomic term, “protomammals” is a alternative with no misleading phylogenetic implications. -
The Teleost Intramandibular Joint: a Mechanism That Allows Fish to Obtain Prey Unavailable to Suction Feeders Alice C
Integrative and Comparative Biology Advance Access published May 21, 2015 Integrative and Comparative Biology Integrative and Comparative Biology, pp. 1–12 doi:10.1093/icb/icv042 Society for Integrative and Comparative Biology SYMPOSIUM The Teleost Intramandibular Joint: A mechanism That Allows Fish to Obtain Prey Unavailable to Suction Feeders Alice C. Gibb,1,* Katie Staab,† Clinton Moran* and Lara A. Ferry‡ *Department of Biology, Northern Arizona University, Flagstaff, AZ 86011-5640; †Biology Department, McDaniel College, Westminster, MD 21157; ‡School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85069-7100 From the symposium ‘‘New Insights into Suction Feeding Biomechanics and Evolution’’ presented at the annual meeting of the Society for Integrative and Comparative Biology, January 3–7, 2015 at West Palm Beach, Florida. 1Email: [email protected] Downloaded from Synopsis Although the majority of teleost fishes possess a fused lower jaw (or mandible), some lineages have acquired a secondary joint in the lower jaw, termed the intramandibular joint (IMJ). The IMJ is a new module that formed within http://icb.oxfordjournals.org/ the already exceptionally complex teleost head, and disarticulation of two bony elements of the mandible potentially creates a ‘‘double-jointed’’ jaw. The apparent independent acquisition of this new functional module in divergent lineages raises a suite of questions. (1) How many teleostean lineages contain IMJ-bearing species? (2) Does the IMJ serve the same purpose in all teleosts? (3) Is the IMJ associated with altered feeding kinematics? (4) Do IMJ-bearing fishes experience trade-offs in other aspects of feeding performance? (5) Is the IMJ used to procure prey that are otherwise unavailable? The IMJ is probably under-reported, but has been documented in at least 10 lineages within the Teleostei. -
Connecting the Chondrocranium: Biomechanics of the Suspensorium in Reptiles
70 (3): 275 – 290 © Senckenberg Gesellschaft für Naturforschung, 2020. 2020 VIRTUAL ISSUE on Recent Advances in Chondrocranium Research | Guest Editor: Ingmar Werneburg Connecting the chondrocranium: Biomechanics of the suspensorium in reptiles Alec T. Wilken 1, *, Kaleb C. Sellers 1, Ian N. Cost 2, Rachel E. Rozin 1, Kevin M. Middleton 1 & Casey M. Holliday 1 1 Department of Pathology and Anatomical Sciences, University of Missouri, M263, Medical Sciences Building, Columbia, MO, 65212, USA — 2 Department of Biology, Albright College, 13th and Bern Streets, Reading, PA, 19612, USA — * Corresponding author; atwxb6@ mail.missouri.edu Submitted February 07, 2020. Accepted June 8, 2020. Published online at www.senckenberg.de/vertebrate-zoology on June 16, 2020. Published in print on Q3/2020. Editor in charge: Ingmar Werneburg Abstract Gnathostomes all share the common challenge of assembling 1st pharyngeal arch elements and associated dermal bones (suspensorium) with the neurocranium into a functioning linkage system. In many tetrapods, the otic and palatobasal articulations between suspensorium and neurocranial elements form the joints integral for cranial kinesis. Among sauropsids, the otic (quadratosquamosal) joint is a key feature in this linkage system and shows considerable variability in shape, tissue-level construction and mobility among lineages of reptiles. Here we explore the biomechanics of the suspensorium and the otic joint in fve disparate species of sauropsids of different kinetic capacity (two squamates, one non-avian theropod dinosaur, and two avian species). Using 3D muscle modeling, comparisons of muscle moments, joint surface areas, cross-sectional geometries, and fnite element analysis, we characterize biomechanical differences in the resultants of protractor muscles, loading of otic joints, and bending properties of pterygoid bones. -
AMERICAN MUSEUM Novitates PUBLISHED by the AMERICAN MUSEUM of NATURAL HISTORY CENTRAL PARK WEST at 79TH STREET, NEW YORK, N.Y
AMERICAN MUSEUM Novitates PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK, N.Y. 10024 Number 2827, pp. 1-57, figs. 1-45 August 13, 1985 An Essay on Euteleostean Classification DONN E. ROSEN' ABSTRACT The anatomy of the occipital region and rostral letic and raises questions about the monophyly of cartilage in euteleostean fishes is reviewed in some the fishes formerly grouped in the Osmeroidei. detail. These data, in combination with other an- Evidence is presented on how the occipital region atomical features taken from the literature, have might be used in acanthomorph systematics, and led to a reassessment of interrelationships within includes reasons for rejecting the concept of the the Euteleostei. This review supports the notions Paracanthopterygii, as this group was formerly that the Salmoniformes, Aulopiformes, Mycto- constituted. phiformes, and Beryciformes are nonmonophy- INTRODUCTION The earliest general classification of fishes dan (1923), A. Smith-Woodward (1932), in which it is possible to pick out many of Norman (1934), Berg (1940) and its various the main components of the Euteleostei is translations, reprinted editions and slightly that ofJohannes Muller (1844), in which the modified versions, and lastly Greenwood et teleosts as a whole were presented as a ver- al. (1966), McAllister (1968), and J. Nelson tebrate subclass, and their components as or- (1984)] went through an evolution from the ders. These orders of Muller's bore names early nonsubordinated, ordinal classifica- that may seem strange and unfamiliar to to- tions of Muller (1844), Agassiz (1858), Gill day's student, but the etymological charac- (1872), Boulenger (1904), and Regan (1909, teristics of many of them were preserved for 1929), to the complex subordinated, hierar- some time, a few even to the present. -
Amniote Phylogeny and the Importance of Fossils
Clndistirs (1988)4: 105-209 AMNIOTE PHYLOGENY AND THE IMPORTANCE OF FOSSILS Jacques Gauthierl,3,Arnold G. Klugel, and Timothy Rowe2 I Museum of ,500logy and Department of Biology, University of Michigan, Ann Arbor, MI 48109-1079; Department of Geological Sciences, University of Texas, Austin, TX 78713-7909, U.S.A. Ah.~/mcl Srvrral prominrnt cladists haw qurstioiied thc importancc of fossils in phylogrnctic inference, and it is becoming iiicreasingly popular to simply fit extinct forms, ifthcy are considered at all, 10 a cladogram ofReccnt taxa. Gardiner’s [ 1982) arid Lovtrup’s [ 1985) study ofamniote phylogeny rxcmplilirs this dilfrrrntial treatment, and we focuard on that group of organisms to test the proposition that hssils c;mnot overturn a theory of‘relatioiiships based only on the Recent biota. Our parsimony analysis of amniotc phylogrny, special knowledge contributed by fossils being scrupulously avoided, led to the followiiig best fitting classification, which is similar to the novel hypothesis Gardiner published: (lcpidmaurs (turtles (mammals (birds, crocodiles)))).However, adding fossils resulted in a markedly dilfcrcnt most parsimonious cladogram or thc extant taxa: (mammals (turtles (lepidosaurs [birds, crocodilrs)))).‘l‘hat classification is likr thr traditional hypothesis, and it provides a brttrr fit to the stratigraphic rrcord. ‘1.0 isolate thr extinct taxa rcsponsihle for the lattcr c,lassification, thr data wrrr succcssi~elypartitioned with each phylogenetic analysis, and wc coneluded that: (1) the ingroup, not the outgroup, fossils were important; (2) synapsid, not reptile, fossils wcrc pivotal; (3) certain syiiapsid fossils, not the rarliest or latrst, were responsible. ‘Ihr critical nature of thr syiiapsid lossils sremcd to lir in the particular comhinatioti of primitive arid derivrd c.haracter states they exhibited.