Early Development of the Shoulder Girdle and Sternum in Marsupials (Mammalia: Metatheria)

  • Milan Klima

Part of the Advances in Anatomy Embryology and Cell Biology book series (ADVSANAT, volume 109)

Table of contents

  1. Front Matter
    Pages I-VII
  2. Milan Klima
    Pages 3-8
  3. Milan Klima
    Pages 9-53
  4. Milan Klima
    Pages 54-80
  5. Milan Klima
    Pages 81-82
  6. Back Matter
    Pages 83-94

About this book

Introduction

The development of the breast-shoulder apparatus in the Marsupialia was inves­ tigated and compared with the conditions in Monotremata and Placentalia. The results were achieved by the investigation of material comprising altogether 109 histological serial sections of intrauterine embryos, neonates, and pouch young from 11 marsupial species. Additionally, 54 skeletons of subadult and adult marsupials from 25 species were included for comparison. The embryonic states show a strong similarity to the developmental stage of the breast-shoulder apparatus in the monotremes. In contrast, the adult breast-shoulder apparatus generally corresponds to that in placentals. The following elements can be observed in the marsupial breast-shoulder apparatus during embryogenesis: scapula, metacoracoid, procoracoid, first rib, paired sternal elements, unpaired sternal element, and clavicle. All the elements mentioned together form a compact, continuous arch in both the intrauterine embryos and the neonates. In the pouch young, this arch is reduced rather soon after birth, so that a compact connection between the left and the right half of the body no longer exists. All that remains is a loose connection via the clavicle. The metacoracoid becomes the processus coracoideus scapulae. The procoracoid becomes the praeclavium. The unpaired sternal element fuses with the paired sternal element, generating the uniform manubrium sterni. The first rib takes its usual position in the thorax. In the pouch young, the breast­ shoulder apparatus as a whole already shows all the typical characteristics that can be determined in adults.

Keywords

Mammalia development embryo evolution marsupials morphogenesis reptiles

Authors and affiliations

  • Milan Klima
    • 1
  1. 1.Anatomisches InstitutJohann Wolfgang Goethe-UniversitätFrankfurt am MainGermany

Bibliographic information

  • DOI https://doi.org/10.1007/978-3-642-72994-2
  • Copyright Information Springer-Verlag Berlin Heidelberg 1987
  • Publisher Name Springer, Berlin, Heidelberg
  • eBook Packages Springer Book Archive
  • Print ISBN 978-3-540-18358-7
  • Online ISBN 978-3-642-72994-2
  • Series Print ISSN 0301-5556
  • Series Online ISSN 2192-7065
  • About this book
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