Cartilage, bone, and intermandibular connective tissue in the australian lungfish, Neoceratodus forsteri (Osteichthyes: Dipnoi)

Authors

  • Anne Kemp

    Corresponding author
    1. Australian Rivers Institute, Griffith University, Queensland, Australia
    • Correspondence to: A. Kemp, Australian Rivers Institute, Griffith University, 170 Kessels Road, Nathan, Brisbane, Queensland 4111, Australia. E-mail: a.kemp@griffith.edu.au

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ABSTRACT

The connective tissue that links the bones of the mandible in the Australian lungfish, Neoceratodus forsteri, has been described as an intermandibular cartilage, and as such has been considered important for phylogenetic analyses among lower vertebrates. However, light and electron microscopy of developing lungfish jaws demonstrates that the intermandibular tissue, like the connective tissue that links the bones of the upper jaw, contains fibroblasts and numerous bundles of collagen fibrils, extending from the trabeculae of the bones supporting the tooth plates. It differs significantly in structure and in staining reactions from the cartilage and the bone found in this species. In common with the cladistian Polypterus and with actinopterygians and some amphibians, lungfish have no intermandibular cartilage. The connective tissue linking the mandibular bones has no phylogenetic significance for systematic grouping of lungfish, as it is present in a range of different groups among lower vertebrates. J. Morphol. 274:1085–1089, 2013. © 2013 Wiley Periodicals, Inc.

Ancillary