Document Detail


Microspectrophotometric evidence for cone monochromacy in sharks.
MedLine Citation:
PMID:  21212930     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Sharks are apex predators, and their evolutionary success is in part due to an impressive array of sensory systems, including vision. The eyes of sharks are well developed and function over a wide range of light levels. However, whilst close relatives of the sharks-the rays and chimaeras-are known to have the potential for colour vision, an evolutionary trait thought to provide distinct survival advantages, evidence for colour vision in sharks remains equivocal. Using single-receptor microspectrophotometry, we measured the absorbance spectra of visual pigments located in the retinal photoreceptors of 17 species of shark. We show that, while the spectral tuning of the rod (wavelength of maximum absorbance, λ(max) 484-518 nm) and cone (λ(max) 532-561 nm) visual pigments varies between species, each shark has only a single long-wavelength-sensitive cone type. This suggests that sharks may be cone monochromats and, therefore, potentially colour blind. Whilst cone monochromacy on land is rare, it may be a common strategy in the marine environment: many aquatic mammals (whales, dolphins and seals) also possess only a single, green-sensitive cone type. It appears that both sharks and marine mammals may have arrived at the same visual design by convergent evolution. The spectral tuning of the rod and cone pigments of sharks is also discussed in relation to their visual ecology.
Authors:
Nathan Scott Hart; Susan Michelle Theiss; Blake Kristin Harahush; Shaun Patrick Collin
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-1-7
Journal Detail:
Title:  Die Naturwissenschaften     Volume:  -     ISSN:  1432-1904     ISO Abbreviation:  -     Publication Date:  2011 Jan 
Date Detail:
Created Date:  2011-1-7     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0400767     Medline TA:  Naturwissenschaften     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
School of Animal Biology, The University of Western Australia, Crawley, WA, 6009, Australia, nathan.hart@uwa.edu.au.
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