The retinal topography of the red lionfish (Pterois volitans): towards an understanding of the visual system of a highly invasive species

Ibáñez, Juan P. (2023) The retinal topography of the red lionfish (Pterois volitans): towards an understanding of the visual system of a highly invasive species. Masters thesis, Memorial University of Newfoundland.

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Abstract

Retinal specializations provide organisms with the spatial information needed to engage in visually guided behaviours aimed at maximizing fitness; nevertheless, little is known about the retinal topography of crepuscular fish, as most studies address diurnal or deep-sea species. I evaluated the types of photoreceptor and neural cells in the retina of the red lionfish, their distribution in the retinal surface, and their spatial resolving power. Single, double and triple cones are imbedded in a rod-dominated field over the entire inner layer. Single and double cones occur in higher densities towards the dorsal and ventral areas, arranged in a square mosaic pattern all along except in the central region of the retina, where they concur with triple cones. Ganglion and amacrine cells cover the outer layer with higher densities in the ventral-nasal region, a mismatch to single and double cones, and occasionally assemble as glomeruli or striation. Cell distribution and single and double cone arrangements in conjunction with spatial resolving power values suggest vision in P. volitans is adapted for vertically open habitats and performs better in dim-light environments while maintaining a moderate capacity for color vision, which denotes an advantage for predatory capabilities and success as an invasive species.

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