The Vertebrates Overview


A few years ago, I suggested to a paleo professor that it would be interesting to run a graduate seminar around individual bones. Much is written about bones as synapomorphies, bones as functional units, and, of course, naked lists of bones for students to memorize are infamous; but there is little continuity. It might be interesting to look at these pieces of anatomy as individual units of evolutionary change. Not only might this give us a new perspective on evolution, but also perhaps some new ideas about the meaning of homology and the evolution of function.

That project was well beyond me, and remains so. However, if I were one to wait on competence before execution, these Notes would not exist. So, as with the remainder of these notes, I will do my learning in public, like a mental web-cam. As with everything else here, we will evolve, rather than build. The coverage will begin generally with the head, but fairly randomly otherwise. It is not a project designed to be completed, or remain static. So the reader may expect the usual incomplete format changes, unexplained gaps in coverage, substantive and typographical errors.

Links: For a compact treatment of the dermal cranial bones, see Justin Tweet's glossary. Some of the Tree of Life pages by Michael Laurin and colleagues are very useful, although their use of color is distracting. See, for example, Phylogeny and Classification of Amniotes. The Dinosaur Encyclopedia is a (literally) bare-bones, but serviceable, guide to dinosaur osteology. For mammals, there is an excellent set of figures and text at the University of Michigan Animal Diversity Web's Mammal Anatomy Contents. Another useful mammalian osteology site is Prof. LC Todd's Bisonosteology page. ATW031129.

I.    THE BRAINCASE Neurocranium or Chondrocranium)
    A.    The Ethmoid Region
        1. Ethmoid
    B.    The Occiput
        1. Paroccipital Process: see Opisthotic
    C.    The Otic Region
        1. Dermosphenotic
        2. Mastoid
        3. Opisthotic
        4. Prootic
    D.    The Sphenoid Region

        1. Basisphenoid
        2. Pleurosphenoid
        3. Sphenethmoid

        1. Canines
        2. Molars
        3. Tooth Implantation

III.    THE DERMAL BONES (Dermatocranium)
Facial Series
        1. Internasal
2. Premaxilla
        3. Septomaxilla
    B.    Mandibular Series
        1. Dentary
        2. Gular
        3. Infradentaries (see Surangular)
        4. Surangular
    D.    Opercular Series
        1. Opercular
    C.    Orbital Series
        1. Jugals
    D.    Palatal Series
        1. Palatines

    A.    Incus

V.    GILL ARCH DERIVATIVES (Splanchnocranium)
    A. The Mandibular Arch
        1. Meckel's Cartilage
    B. The Hyoid Arch
        1. Hypohyal
    C.  The Branchial Arches
        1. The Epibranchials
    D.  Other derivatives
        1. See Ear: Incus

checked ATW060112