The Retinal Pigments of Filter-feeding Sharks (Rhincodon typus, Cetorhinus maximus, and Megachasma pelagios) and their Role in Foraging Ecology
Date
2020-04-08
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Honors Program, The University of Tampa
Abstract
The spectral tuning properties of the whale shark (Rhincodon typus), basking shark
(Cetorhinus maximus), and megamouth shark (Megachasma pelagios) rod (Rh1) and longwavelength
sensitive (LWS) cone visual pigments were examined to determine whether these
retinal pigments have adapted to the broadband light spectrum available for surface foraging, or
to the narrowband blue-shifted light spectrum available at depth. Recently published whale shark
Rh1 and LWS cone opsin genes were used to design primers for amplification and sequencing of
the opsin proteins from basking and megamouth sharks. Basking and megamouth shark Rh1 and
LWS cone coding sequences were PCR amplified and sequenced to identify amino acid residues
critical for spectral tuning. The predicted absorbance maxima (λmax) for the whale, basking, and
megamouth shark Rh1 visual pigments were 496 nm, 496 nm, and 488 nm, respectively. The
deduced amino acid sequence for both the whale and basking shark LWS cone opsins resulted in
predicted λmax values near 500 nm. Although Rh1 λmax values near 500 nm are typical of
terrestrial vertebrates and surface foraging fish, it is uncommon for vertebrate LWS cone
pigments to be so greatly blue-shifted. We propose that the spectral tuning properties of the Rh1
and LWS cone pigments in whale and basking sharks are most likely an adaptation to the
broadband light spectrum available at the surface, while the megamouth shark Rh1 pigment is
most likely an adaptation to the narrowband light spectrum available in deeper waters.
Description
Recommended Citation: Serba, Katherine M. “The Retinal Pigments of Filter-Feeding Sharks (Rhincodon Typus, Cetorhinus Maximus, and Megachasma Pelagios) and Their Role in Foraging Ecology.” Honors Program, The University of Tampa, 2020. https://doi.org/10.48497/T8WQ-5X45.
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Undergraduate Thesis
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Keywords
Filter-feeding sharks, Visual pigments, Foraging ecology
Citation
Serba, Katherine M. “The Retinal Pigments of Filter-Feeding Sharks (Rhincodon Typus, Cetorhinus Maximus, and Megachasma Pelagios) and Their Role in Foraging Ecology.” Honors Program, The University of Tampa, 2020. https://doi.org/10.48497/T8WQ-5X45.