Cone monochromacy and visual pigment spectral tuning in wobbegong sharks

Theiss, Susan M.; Davies, Wayne I. L.; Collin, Shaun P.; Hunt, David M.; Hart, Nathan S.

doi:10.1098/rsbl.2012.0663

Cited by 24 publications

(30 citation statements)

References 25 publications

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“…The complement of cone receptor types extends sensitivity across more of the visible spectrum and provides the potential for color vision. The ability to discriminate color appears to have been lost in true sharks (Selachii), which possess only a single cone type in addition to a rod [Hart et al, 2011;Theiss et al, 2012]. The low rod-to-cone ratio (12: 1) in the elephant shark is similar to species of sharks and rays that live in dim-light conditions, i.e., H. ocellatum (18: 1), O. ornatus (19: 1) [Litherland and Collin, 2008], and Isurus oxyrinchus (10: 1) [Gruber et al, 1975].…”

Section: Discussionmentioning

confidence: 99%

Retinal Morphology and Visual Specializations in Three Species of Chimaeras, the Deep-Sea R. pacifica and C. lignaria, and the Vertical Migrator C. milii (Holocephali)

2018

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The majority of holocephalans live in the mesopelagic zone of the deep ocean, where there is little or no sunlight, but some species migrate to brightly lit shallow waters to reproduce. This study compares the retinal morphology of two species of deep-sea chimaeras, the Pacific spookfish (Rhinochimaera pacifica) and the Carpenter’s chimaera (Chimaera lignaria), with the elephant shark (Callorhinchus milii), a vertical migrator that lives in the mesopelagic zone but migrates to shallow water to reproduce. The two deep-sea chimaera species possess pure rod retinae with long photoreceptor outer segments that might serve to increase visual sensitivity. In contrast, the retina of the elephant shark possesses rods, with an outer-segment length significantly shorter (a mean of 34 µm) than in the deep-sea species, and cones, and therefore the potential for color vision. The retinal ganglion cell distribution closely follows that of the photoreceptor populations in all three species, but there is a lower peak density of these cells in both deep-sea species (215–275 cells/mm² vs. 769 cells/mm² in the elephant shark), which represents a significant increase in the convergence of visual information (summation ratio) from photoreceptors to ganglion cells. It is evident that the eyes of deep-sea chimaeras have increased sensitivity to detect objects under low levels of light, but at the expense of both resolution and the capacity for color vision. In contrast, the elephant shark has a lower sensitivity, but the potential for color discrimination and a higher visual acuity.

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Section: Discussionmentioning

confidence: 99%

Retinal Morphology and Visual Specializations in Three Species of Chimaeras, the Deep-Sea R. pacifica and C. lignaria, and the Vertical Migrator C. milii (Holocephali)

2018

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“…Cartilaginous fi shes are divided into two lineages, the holocephalans (chimaeras) and the elasmobranchs (sharks, rays, and skates), and recent work implies that the SWS1 gene has been lost from both lineages. In contrast, rays possess three spectral classes of cone, although none of these has a λ max suggestive of a SWS1 pigment (Hart et al, 2004 ;Theiss et al, 2007 ), and sharks appear to be L cone monochromats with just a single cone type expressing an LWS pigment (Hart et al, 2011 ;Theiss et al, 2012 ). Among the elasmobranchs, skates possess a rod-only retina with no evidence for the presence of cones or the expression of cone opsins in the retina (Brin & Ripps, 1977 ;Cornwall et al, 1989 ;O'Brien et al, 1997 ).…”

Section: S Cone Loss In Fi Shesmentioning

confidence: 99%

S cones: Evolution, retinal distribution, development, and spectral sensitivity

Hunt

Peichl

2013

Vis Neurosci

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S cones expressing the short wavelength-sensitive type 1 (SWS1) class of visual pigment generally form only a minority type of cone photoreceptor within the vertebrate duplex retina. Hence, their primary role is in color vision, not in high acuity vision. In mammals, S cones may be present as a constant fraction of the cones across the retina, may be restricted to certain regions of the retina or may form a gradient across the retina, and in some species, there is coexpression of SWS1 and the long wavelength-sensitive (LWS) class of pigment in many cones. During retinal development, SWS1 opsin expression generally precedes that of LWS opsin, and evidence from genetic studies indicates that the S cone pathway may be the default pathway for cone development. With the notable exception of the cartilaginous fishes, where S cones appear to be absent, they are present in representative species from all other vertebrate classes. S cone loss is not, however, uncommon; they are absent from most aquatic mammals and from some but not all nocturnal terrestrial species. The peak spectral sensitivity of S cones depends on the spectral characteristics of the pigment present. Evidence from the study of agnathans and teleost fishes indicates that the ancestral vertebrate SWS1 pigment was ultraviolet (UV) sensitive with a peak around 360 nm, but this has shifted into the violet region of the spectrum (>380 nm) on many separate occasions during vertebrate evolution. In all cases, the shift was generated by just one or a few replacements in tuning-relevant residues. Only in the avian lineage has tuning moved in the opposite direction, with the reinvention of UV-sensitive pigments.

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“…In addition to a single spectral type of rod, only one spectral type of cone visual pigment has been measured in sharks: the λ max of the cone pigment ranges from 532 nm in the blacktip shark ( Carcharhinus limbatus Müller & Henle, 1839) to 561 nm in the ornate wobbegong shark ( Orectolobus ornatus De Vis, 1883) (Hart et al ; Theiss et al ). Although visual pigments have been characterized in very few of the more than 500 described species of shark (Last & Stevens ), based on the diversity of the species studied it seems likely that cone monochromacy is widespread throughout the taxon.…”

Section: An Overview Of Shark Sensory Abilitiesmentioning

confidence: 99%

Sharks senses and shark repellents

Hart

Collin

2015

Integrative Zoology

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Despite over 70 years of research on shark repellents, few practical and reliable solutions to prevent shark attacks on humans or reduce shark bycatch and depredation in commercial fisheries have been developed. In large part, this deficiency stems from a lack of fundamental knowledge of the sensory cues that drive predatory behavior in sharks. However, the widespread use of shark repellents is also hampered by the physical constraints and technical or logistical difficulties of deploying substances or devices in an open-water marine environment to prevent an unpredictable interaction with a complex animal. Here, we summarize the key attributes of the various sensory systems of sharks and highlight residual knowledge gaps that are relevant to the development of effective shark repellents. We also review the most recent advances in shark repellent technology within the broader historical context of research on shark repellents and shark sensory systems. We conclude with suggestions for future research that may enhance the efficacy of shark repellent devices, in particular, the continued need for basic research on shark sensory biology and the use of a multi-sensory approach when developing or deploying shark repellent technology.

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Cone monochromacy and visual pigment spectral tuning in wobbegong sharks

Cited by 24 publications

References 25 publications

Retinal Morphology and Visual Specializations in Three Species of Chimaeras, the Deep-Sea R. pacifica and C. lignaria, and the Vertical Migrator C. milii (Holocephali)

Retinal Morphology and Visual Specializations in Three Species of Chimaeras, the Deep-Sea R. pacifica and C. lignaria, and the Vertical Migrator C. milii (Holocephali)

S cones: Evolution, retinal distribution, development, and spectral sensitivity

Sharks senses and shark repellents

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