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A systemic secondary vessel system is present in the teleost fish Tandanus tandanus and absent in the elasmobranchs Carcharhinus melanopterus and Rhinobatos typus and in the dipnoan Neoceratodus forsteri

Authors

  • Lisa K. Chopin,

    Corresponding author
    1. Department of Anatomical Sciences, University of Queensland, St. Lucia, Queensland 4072, Australia
      All correspondence to: Dr Lisa Chopin, Farm Animal Studies, PO Box 125, Kenmore Q 4069, Australia. E-mail: j.chopin@mailbox.uq.edu.au
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  • Andrew P. Amey,

    1. Department of Anatomical Sciences, University of Queensland, St. Lucia, Queensland 4072, Australia
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  • Michael B. Bennett

    1. Department of Anatomical Sciences, University of Queensland, St. Lucia, Queensland 4072, Australia
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All correspondence to: Dr Lisa Chopin, Farm Animal Studies, PO Box 125, Kenmore Q 4069, Australia. E-mail: j.chopin@mailbox.uq.edu.au

Abstract

A system of secondary vessels emerging from the primary vessels as numerous coiled capillaries has been described in numerous teleost and holost fishes. The systemic secondary vessels of the teleost Tandanus tandanus are typical of this system and are described in this study. The existence of a secondary vessel system has been postulated in the elasmobranch group. No secondary vessel origins, as seen in the teleosts, are present in the elasmobranchs Rhinobatos typus and Carcharhinus melanopterus. Vessels with a similar distribution to secondary arteries are observed but these are venous rather than arterial in nature and do not connect with the primary arteries. Like the secondary veins in teleosts, the cutaneous veins in R. typus contain blood with a low haematocrit. There is no morphological evidence for a secondary vessel system in the dipnoan Neoceratodus forsteri.

Ancillary