Ocular morphology of the Baikal sculpin-oilfishes,Comephorus baicalensis and C. dybowskii (Comephoridae) |
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Authors: | Neville W Pankhurst Valentina G Sideleva Patricia M Pankhurst Olga Smirnova John Janssen |
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Institution: | (1) Leigh Marine Laboratory, University of Auckland, Private Bag, 92019 Auckland, New Zealand;(2) Limnological Institute, P.O. Box 4199, 664033 Irkutsk, Russia;(3) Department of Biology, Loyola University, 6525 North Sheridan Road, Chicago, IL 60626, USA |
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Abstract: | Synopsis Baikal sculpin-oilfishes (Comephorus baicalensis and C. dybowskii) were captured from Lake Baikal by mid-water trawl. External morphology was assessed using camera lucida drawings of whole
heads. Retinal morphology was examined in material prepared for light and electron microscopy. A single rod-like photoreceptor
is present in the retina, and this is at low density compared with marine species of similar depth distribution. C. baicalensis displays tubular eyes, with a dorsally displaced spherical lens and pupil, creating a dorsally directed visual axis. This
corresponds to an area with a high density of photoreceptors in the ventral retina. Retinal structure is very similar in C. dybowskii with the exception that regional variation of cell densities within the retina is less marked than in C. baicalensis. In contrast to C. baicalensis, C. dybowskii has a caudal aphakic space and highest photoreceptor density in the rostral retina. Both species display changes in body
attitude in association with diurnal vertical migration. We suggest that this may facilitate inspection of the water column
from which predator strikes are most likely to occur. Comephorus in general display less specialization for vision in low light than marine counterparts with similar depth distributions. |
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Keywords: | Vision Retina Photoreceptors Eye morphology |
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