Leis' conundrum: Homology of the clavus of the ocean sunfishes. 1. Ontogeny of the median fins and axial skeleton of Monotrete leiurus (Teleostei, Tetraodontiformes, Tetraodontidae)

Authors

  • Ralf Britz,

    Corresponding author
    1. Divison of Fishes, National Museum of Natural History, Smithsonian Institution, Washington DC, USA
    2. Department of Zoology, The Natural History Museum, London, UK
    • Department of Zoology, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
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  • G. David Johnson

    1. Divison of Fishes, National Museum of Natural History, Smithsonian Institution, Washington DC, USA
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Abstract

We describe the ontogeny of the axial skeleton and median fins of the Southeast Asian freshwater puffer Monotrete leiurus, based on a reared developmental series. Most elements of the axial skeleton in M. leiurus arise in membrane bone. Only the base of the anterior three neural arches, the base of the hemal arches of the third preural centrum, the neural and hemal arches and spines of the second preural centrum, the parhypural, the two hypural plates, and the single epural are preformed in cartilage. In contrast to most teleosts, the proximal-middle radials of the dorsal and anal fins are upright and symmetrical and their distal tips coalesce during development to form a deep band of cartilage, from which the spherical distal radials are spatially separated. © 2004 Wiley-Liss, Inc.

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