Abstract
Scanning electron microscopy, microspectrophotometry, and spectrophotometry of digitonin extracts were employed to characterize the photoreceptors and visual pigments of two freshwater Acipenseriformes. The retinas of the shovelnose sturgeon, Scaphirhynchus platorynchus (Acipenseridae), and the paddlefish, Polyodon spathula (Polyodontidae) are dominated by large rods with long, broad outer segments. A second rod, rare and much narrower than the dominant rod, is present in Scaphirhynchus but not seen in Polyodon. The absorbance maximum of the visual pigment in the rods of Polyodon is near 540 nm; that of Scaphirhynchus near 534 nm. The retinas of both species contain substantial numbers of large, single cones, about 33% of the photoreceptors in Scaphirhynchus; 37% in Polyodon. Scaphirhynchus cone pigments have absorbance maxima near 610 nm, 521 nm and 470 nm, respectively. Polyodon cone pigments absorb maximally near 607 nm and 535 nm, respectively. All visual pigments are based on vitamin A2. The data are compared to those from other Acipenseriformes and are discussed in terms of lifestyle and behavior.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Accepted: 7 October 1998
Rights and permissions
About this article
Cite this article
Sillman, A., O'Leary, C., Tarantino, C. et al. The photoreceptors and visual pigments of two species of Acipenseriformes, the shovelnose sturgeon (Scaphirhynchus platorynchus ) and the paddlefish (Polyodon spathula ). J Comp Physiol A 184, 37–47 (1999). https://doi.org/10.1007/s003590050304
Issue Date:
DOI: https://doi.org/10.1007/s003590050304