Morphometry and microanatomy of the barbels of the common sawshark Pristiophorus cirratus (Pristiophoridae): implications for pristiophorid behaviour |
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| Authors: | R. J. Nevatte J. E. Williamson N. G. F. Vella V. Raoult B. E. Wueringer |
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| Affiliation: | 1. Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia;2. Microscopy Unit, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109, Australia;3. College of Marine and Environmental Sciences, James Cook University, Cairns, QLD 4870, Australia;4. Sharks and Rays Australia, Bungalow, QLD 4870, Australia |
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| Abstract: | The internal anatomy of the barbels of the common sawshark Pristiophorus cirratus was examined with light microscopy to clarify their sensory role. No sensory structures such as taste buds (chemoreception), ampullae of Lorenzini (electroreception) or free neuromasts (lateral line mechanoreception) could be located in the barbels. The presence of bundles of nerve fibres, however, indicates a tactile function for the barbels. Conveyance of information regarding potentially damaging stimuli (nociception) and temperature (thermoception) cannot be excluded at this stage. It is hypothesized that the barbels are used by P. cirratus to locate prey in both the water column and on the substratum via wake detection and sensing changes in surface texture. The barbels may also be involved in the detection of water currents for rheotaxis. Regression analyses on P. cirratus morphometric data showed that the width of the rostrum at two sections (the barbels and the rostrum tip) does not significantly correlate with total length. The regression analyses also suggested that the barbels of P. cirratus may be lateralised. |
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| Keywords: | histology lateralisation morphometrics tactile sense |
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