Physical and morphological aspects of the eye of the manatee trichechus inunguis natterer 1883: (Sirenia: Mammalia) |
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Authors: | Erich K. Ritter Juerg M. Brunnschweiler |
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Affiliation: | 1. Shark Research Institute , P.O. Box 40, Princeton, NJ, 08540, USA;2. Zoological Institute , University of Zurich , Winterthurerstrasse 190, Zurich, CH-8057, Switzerland |
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Abstract: | The eyes and aspects of vision of the Amazonian manatee Trichechus inunguis NATTERER 1883: (Sirenia: mammalia) have been examined in five animals, in relation to previous findings for sirenians. This paper presents a review of previous findings confirming those upon gross ocular anatomy, retinal histology and ocular refraction. The confirmation of a primarily rod retina, high receptor: ganglion cell ratio and low refractive error under water were of note. A visual pigment based upon vitamin A1 and a difference spectrum of λ max at 505 nm was in agreement with Dartnalls nomogram. The findings suggest a retina more suited to low light levels and at best, moderate visual acuity, though motion perception appears present and a low degree of binocular vision possible. |
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Keywords: | Sharksucker Shark Jump Behaviour Irritation |
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