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Lesku JA, Libourel PA, Kelly ML, Hemmi JM, Kerr CC, Collin SP, Radford CA. An electrophysiological correlate of sleep in a shark. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2024. [PMID: 38957102 DOI: 10.1002/jez.2846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 06/11/2024] [Accepted: 06/13/2024] [Indexed: 07/04/2024]
Abstract
Sleep is a prominent physiological state observed across the animal kingdom. Yet, for some animals, our ability to identify sleep can be masked by behaviors otherwise associated with being awake, such as for some sharks that must swim continuously to push oxygenated seawater over their gills to breathe. We know that sleep in buccal pumping sharks with clear rest/activity cycles, such as draughtsboard sharks (Cephaloscyllium isabellum, Bonnaterre, 1788), manifests as a behavioral shutdown, postural relaxation, reduced responsiveness, and a lowered metabolic rate. However, these features of sleep do not lend themselves well to animals that swim nonstop. In addition to video and accelerometry recordings, we tried to explore the electrophysiological correlates of sleep in draughtsboard sharks using electroencephalography (EEG), electromyography, and electrooculography, while monitoring brain temperature. The seven channels of EEG activity had a surprising level of (apparent) instability when animals were swimming, but also when sleeping. The amount of stable EEG signals was too low for replication within- and across individuals. Eye movements were not measurable, owing to instability of the reference electrode. Based on an established behavioral characterization of sleep in draughtsboard sharks, we offer the original finding that muscle tone was strongest during active wakefulness, lower in quietly awake sharks, and lowest in sleeping sharks. We also offer several critical suggestions on how to improve techniques for characterizing sleep electrophysiology in future studies on elasmobranchs, particularly for those that swim continuously. Ultimately, these approaches will provide important insights into the evolutionary confluence of behaviors typically associated with wakefulness and sleep.
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Affiliation(s)
- John A Lesku
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
| | - Paul-Antoine Libourel
- Center for Functional and Evolutionary Ecology, MAD Team, Montpellier, France
- Neuroscience Research Center of Lyon, Sleep Team, Bron, France
| | - Michael L Kelly
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
- Australian Centre for Disease Preparedness, Commonwealth Scientific and Industrial Research Organisation, Geelong, Victoria, Australia
| | - Jan M Hemmi
- School of Biological Sciences, The University of Western Australia, Perth, Western Australia, Australia
- Oceans Institute, The University of Western Australia, Perth, Western Australia, Australia
| | - Caroline C Kerr
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
| | - Shaun P Collin
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
- Oceans Institute, The University of Western Australia, Perth, Western Australia, Australia
| | - Craig A Radford
- Institute of Marine Science, Leigh Marine Laboratory, The University of Auckland, Auckland, New Zealand
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2
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Smart sharks: a review of chondrichthyan cognition. Anim Cogn 2023; 26:175-188. [PMID: 36394656 PMCID: PMC9877065 DOI: 10.1007/s10071-022-01708-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 10/16/2022] [Accepted: 10/20/2022] [Indexed: 11/19/2022]
Abstract
450 million years of evolution have given chondrichthyans (sharks, rays and allies) ample time to adapt perfectly to their respective everyday life challenges and cognitive abilities have played an important part in that process. The diversity of niches that sharks and rays occupy corresponds to matching diversity in brains and behaviour, but we have only scratched the surface in terms of investigating cognition in this important group of animals. The handful of species that have been cognitively assessed in some detail over the last decade have provided enough data to safely conclude that sharks and rays are cognitively on par with most other vertebrates, including mammals and birds. Experiments in the lab as well as in the wild pose their own unique challenges, mainly due to the handling and maintenance of these animals as well as controlling environmental conditions and elimination of confounding factors. Nonetheless, significant advancements have been obtained in the fields of spatial and social cognition, discrimination learning, memory retention as well as several others. Most studies have focused on behaviour and the underlying neural substrates involved in cognitive information processing are still largely unknown. Our understanding of shark cognition has multiple practical benefits for welfare and conservation management but there are obvious gaps in our knowledge. Like most marine animals, sharks and rays face multiple threats. The effects of climate change, pollution and resulting ecosystem changes on the cognitive abilities of sharks and stingrays remain poorly investigated and we can only speculate what the likely impacts might be based on research on bony fishes. Lastly, sharks still suffer from their bad reputation as mindless killers and are heavily targeted by commercial fishing operations for their fins. This public relations issue clouds people's expectations of shark intelligence and is a serious impediment to their conservation. In the light of the fascinating results presented here, it seems obvious that the general perception of sharks and rays as well as their status as sentient, cognitive animals, needs to be urgently revisited.
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3
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The Colours of Octopus: Using Spectral Data to Measure Octopus Camouflage. Vision (Basel) 2022; 6:vision6040059. [PMID: 36278671 PMCID: PMC9590006 DOI: 10.3390/vision6040059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 09/16/2022] [Accepted: 09/16/2022] [Indexed: 11/17/2022] Open
Abstract
No animal can so effectively camouflage in such a wide range of environments as the octopus. Thanks to their highly malleable skin, they are capable of adapting their body patterns to the brightness and texture of their immediate environment, and they often seemingly match the colour of background objects. However, octopuses are colour-blind as their eyes have only one type of visual pigment. Therefore, chromatophores in their skin are likely to respond to changes in brightness, not chromaticity. To determine whether octopuses actually match background colours, we used a SpectraScan® PR-655 spectroradiometer to measure the reflectance spectra of Octopus tetricus skin in captivity. The spectra were compared with those of green algae, brown algae, and sponges—all of these being colourful objects commonly found in the octopus’s natural environment. Even though we show that octopuses change both lightness and chromaticity, allowing them to potentially camouflage in a wide range of backgrounds in an effective manner, the overall octopus colours did not reach the same level of saturation compared to some background objects. Spectra were then modelled under the visual systems of four potential octopus predators: one dichromatic fish (Heller’s barracuda), two trichromatic fish (blue-spotted stingray and two-spotted red snapper), and one tetrachromatic bird (wedge-tailed shearwater). We show that octopuses are able to match certain background colours for some visual systems. How a colour-blind animal is capable of colour-matching is still unknown.
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4
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Okamoto K, Nomura M, Horie Y, Okamura H. Color preferences and gastrointestinal-tract retention times of microplastics by freshwater and marine fishes. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 304:119253. [PMID: 35378197 DOI: 10.1016/j.envpol.2022.119253] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/25/2022] [Accepted: 03/31/2022] [Indexed: 06/14/2023]
Abstract
We examined ingestion and retention rates of microplastics (MPs) by two freshwater (Japanese medaka and zebrafish) and two marine fish species (Indian medaka and clown anemonefish) to determine their color preferences and gastrointestinal-tract retention times. In our ingestion experiments, clown anemonefish ingested the most MP particles, followed by zebrafish, and then Japanese and Indian medaka. Next, we investigated color preferences among five MP colors. Red, yellow, and green MP were ingested at higher rates than gray and blue MPs for all tested fish species. To test whether these differences truly reflect a recognition of and preference for certain colors based on color vision, we investigated the preferences of clown anemonefish for MP colors under light and dark conditions. Under dark conditions, ingestion of MP particles was reduced, and color preferences were not observed. Finally, we assessed gastrointestinal-tract retention times for all four fish species. Some individuals retained MP particles in their gastrointestinal tracts for over 24 h after ingestion. Our results show that fish rely on color vision to recognize and express preferences for certain MP colors. In addition, MP excretion times varied widely among individuals. Our results provide new insights into accidental MP ingestion by fishes.
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Affiliation(s)
- Konori Okamoto
- Faculty of Maritime Sciences, Kobe University, Fukaeminami-machi, Higashinada-ku, Kobe, 658-0022, Japan
| | - Miho Nomura
- Graduate School of Maritime Sciences, Kobe University, Fukaeminami-machi, Higashinada-ku, Kobe, 658-0022, Japan
| | - Yoshifumi Horie
- Research Center for Inland Seas (KURCIS), Kobe University, Fukaeminami-machi, Higashinada-ku, Kobe, 658-0022, Japan.
| | - Hideo Okamura
- Research Center for Inland Seas (KURCIS), Kobe University, Fukaeminami-machi, Higashinada-ku, Kobe, 658-0022, Japan
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5
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Ryan LA, Slip DJ, Chapuis L, Collin SP, Gennari E, Hemmi JM, How MJ, Huveneers C, Peddemors VM, Tosetto L, Hart NS. A shark's eye view: testing the 'mistaken identity theory' behind shark bites on humans. J R Soc Interface 2021; 18:20210533. [PMID: 34699727 PMCID: PMC8548079 DOI: 10.1098/rsif.2021.0533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Shark bites on humans are rare but are sufficiently frequent to generate substantial public concern, which typically leads to measures to reduce their frequency. Unfortunately, we understand little about why sharks bite humans. One theory for bites occurring at the surface, e.g. on surfers, is that of mistaken identity, whereby sharks mistake humans for their typical prey (pinnipeds in the case of white sharks). This study tests the mistaken identity theory by comparing video footage of pinnipeds, humans swimming and humans paddling surfboards, from the perspective of a white shark viewing these objects from below. Videos were processed to reflect how a shark's retina would detect the visual motion and shape cues. Motion cues of humans swimming, humans paddling surfboards and pinnipeds swimming did not differ significantly. The shape of paddled surfboards and human swimmers was also similar to that of pinnipeds with their flippers abducted. The difference in shape between pinnipeds with abducted versus adducted flippers was bigger than between pinnipeds with flippers abducted and surfboards or human swimmers. From the perspective of a white shark, therefore, neither visual motion nor shape cues allow an unequivocal visual distinction between pinnipeds and humans, supporting the mistaken identity theory behind some bites.
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Affiliation(s)
- Laura A Ryan
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia
| | - David J Slip
- Taronga Conservation Society Australia, Bradley's Head Road, Mosman, New South Wales 2088, Australia
| | - Lucille Chapuis
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK
| | - Shaun P Collin
- School of Life Sciences, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Enrico Gennari
- Oceans Research Institute, Mossel Bay 6500, South Africa.,South African Institute for Aquatic Biodiversity, Private Bag 1015, Grahamstown 6140, South Africa.,Department of Ichthyology and Fisheries Science, Rhodes University, Grahamstown 6140, South Africa
| | - Jan M Hemmi
- School of Biological Sciences and The UWA Oceans Institute, M092, University of Western Australia, Perth, Western Australia 6009, Australia
| | - Martin J How
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | - Charlie Huveneers
- College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042, Australia
| | - Victor M Peddemors
- New South Wales Department of Primary Industries, Sydney Institute of Marine Science, Mosman, New South Wales 2088, Australia
| | - Louise Tosetto
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia
| | - Nathan S Hart
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia
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6
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Bass NC, Day J, Guttridge TL, Mourier J, Knott NA, Vila Pouca C, Brown C. Residency and movement patterns of adult Port Jackson sharks (Heterodontus portusjacksoni) at a breeding aggregation site. JOURNAL OF FISH BIOLOGY 2021; 99:1455-1466. [PMID: 34270092 DOI: 10.1111/jfb.14853] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/02/2021] [Accepted: 07/13/2021] [Indexed: 06/13/2023]
Abstract
Examining the movement ecology of mesopredators is fundamental to developing an understanding of their biology, ecology and behaviour, as well as the communities and ecosystems they influence. The limited research on the residency and movements of benthic marine mesopredators has primarily used visual tags, which do not allow for the efficient and accurate monitoring of individual space use. In this study, the authors investigated the residency and movement patterns of Port Jackson sharks Heterodontus portusjacksoni (Meyer 1793) at a breeding aggregation site in Jervis Bay, south-eastern Australia, using passive acoustic telemetry to further our understanding of the movement ecology of these important mesopredators. Between 2012 and 2014, individuals were tagged with acoustic transmitters, and their residency and movements within the bay were monitored for up to 4 years. H. portusjacksoni showed strong preferences for particular reefs within and between breeding seasons. Males had significantly higher residency indices at their favoured sites relative to females, suggesting that males may be engaging in territorial behaviour. Conversely, female H. portusjacksoni exhibited higher roaming indices relative to males indicating that females may move between sites to assess males. Finally, H. portusjacksoni showed temporal variation in movements between reefs with individuals typically visiting more reefs at night relative to the day, dusk and dawn corresponding with their nocturnal habits.
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Affiliation(s)
- Nathan Charles Bass
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Joanna Day
- Taronga Institute of Science and Learning, Taronga Conservation Society Australia, Mosman, New South Wale, Australia
| | | | - Johann Mourier
- UMR MARBEC (IRD, Ifremer, Univ. Montpellier, CNRS), Séte, France
| | - Nathan A Knott
- NSW Department of Primary Industry, Fisheries Research, Huskisson, New South Wales, Australia
| | - Catarina Vila Pouca
- Zoological Institute, Stockholm University, Stockholm, Sweden
- Behavioural Ecology Group, Wageningen University & Research, Wageningen, The Netherlands
| | - Culum Brown
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia
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7
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Schluessel V, Rick IP, Seifert FD, Baumann C, Lee Davies WI. Not just shades of grey: life is full of colour for the ocellate river stingray (Potamotrygon motoro). J Exp Biol 2021; 224:237826. [PMID: 33771913 DOI: 10.1242/jeb.226142] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 03/19/2021] [Indexed: 12/14/2022]
Abstract
Previous studies have shown that marine stingrays have the anatomical and physiological basis for colour vision, with cone spectral sensitivity in the blue to green range of the visible spectrum. Behavioural studies on Glaucostegus typus also showed that blue and grey can be perceived and discriminated. The present study is the first to assess visual opsin genetics in the ocellate river stingray (Potamotrygon motoro) and test whether individuals perceive colour in two alternative forced choice experiments. Retinal transcriptome profiling using RNA-Seq and quantification demonstrated the presence of lws and rh2 cone opsin genes and a highly expressed single rod (rh1) opsin gene. Spectral tuning analysis predicted these vitamin A1-based visual photopigments to exhibit spectral absorbance maxima at 461 nm (rh2), 496 nm (rh1) and 555 nm (lws); suggesting the presence of dichromacy in this species. Indeed, P. motoro demonstrates the potential to be equally sensitive to wavelengths from 380 to 600 nm of the visible spectrum. Behavioural results showed that red and green plates, as well as blue and yellow plates, were readily discriminated based on colour; however, brightness differences also played a part in the discrimination of blue and yellow. Red hues of different brightness were distinguished significantly above chance level from one another. In conclusion, the genetic and behavioural results support prior data on marine stingrays. However, this study suggests that freshwater stingrays of the family Potamotrygonidae may have a visual colour system that has ecologically adapted to a riverine habitat.
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Affiliation(s)
- Vera Schluessel
- Institute of Zoology, Rheinische Friedrich-Wilhelms-Universität Bonn, Poppelsdorfer Schloss, Meckenheimer Allee 169, 53115 Bonn, Germany
| | - Ingolf P Rick
- Institute of Zoology, Rheinische Friedrich-Wilhelms-Universität Bonn, Poppelsdorfer Schloss, Meckenheimer Allee 169, 53115 Bonn, Germany
| | - Friederike Donata Seifert
- Institute of Zoology, Rheinische Friedrich-Wilhelms-Universität Bonn, Poppelsdorfer Schloss, Meckenheimer Allee 169, 53115 Bonn, Germany
| | - Christina Baumann
- Institute of Zoology, Rheinische Friedrich-Wilhelms-Universität Bonn, Poppelsdorfer Schloss, Meckenheimer Allee 169, 53115 Bonn, Germany
| | - Wayne Iwan Lee Davies
- Institute of Zoology, Rheinische Friedrich-Wilhelms-Universität Bonn, Poppelsdorfer Schloss, Meckenheimer Allee 169, 53115 Bonn, Germany.,Umeå Centre for Molecular Medicine (UCMM), Umeå University, 901 87 Umeå, Sweden.,School of Life Sciences, College of Science, Health and Engineering, La Trobe University, Melbourne Campus, Melbourne, VIC 3086, Australia
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8
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Yamaguchi K, Koyanagi M, Kuraku S. Visual and nonvisual opsin genes of sharks and other nonosteichthyan vertebrates: Genomic exploration of underwater photoreception. J Evol Biol 2020; 34:968-976. [DOI: 10.1111/jeb.13730] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 10/21/2020] [Accepted: 10/21/2020] [Indexed: 12/16/2022]
Affiliation(s)
- Kazuaki Yamaguchi
- Laboratory for Phyloinformatics RIKEN Center for Biosystems Dynamics Research (BDR) Kobe Japan
| | - Mitsumasa Koyanagi
- Department of Biology and Geosciences Graduate School of Science Osaka City University Osaka Japan
| | - Shigehiro Kuraku
- Laboratory for Phyloinformatics RIKEN Center for Biosystems Dynamics Research (BDR) Kobe Japan
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9
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Hart NS, Lamb TD, Patel HR, Chuah A, Natoli RC, Hudson NJ, Cutmore SC, Davies WIL, Collin SP, Hunt DM. Visual Opsin Diversity in Sharks and Rays. Mol Biol Evol 2020; 37:811-827. [PMID: 31770430 DOI: 10.1093/molbev/msz269] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The diversity of color vision systems found in extant vertebrates suggests that different evolutionary selection pressures have driven specializations in photoreceptor complement and visual pigment spectral tuning appropriate for an animal's behavior, habitat, and life history. Aquatic vertebrates in particular show high variability in chromatic vision and have become important models for understanding the role of color vision in prey detection, predator avoidance, and social interactions. In this study, we examined the capacity for chromatic vision in elasmobranch fishes, a group that have received relatively little attention to date. We used microspectrophotometry to measure the spectral absorbance of the visual pigments in the outer segments of individual photoreceptors from several ray and shark species, and we sequenced the opsin mRNAs obtained from the retinas of the same species, as well as from additional elasmobranch species. We reveal the phylogenetically widespread occurrence of dichromatic color vision in rays based on two cone opsins, RH2 and LWS. We also confirm that all shark species studied to date appear to be cone monochromats but report that in different species the single cone opsin may be of either the LWS or the RH2 class. From this, we infer that cone monochromacy in sharks has evolved independently on multiple occasions. Together with earlier discoveries in secondarily aquatic marine mammals, this suggests that cone-based color vision may be of little use for large marine predators, such as sharks, pinnipeds, and cetaceans.
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Affiliation(s)
- Nathan S Hart
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, Australia
| | - Trevor D Lamb
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Hardip R Patel
- Department of Genome Sciences, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Aaron Chuah
- Department of Immunology and Infectious Disease, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Riccardo C Natoli
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia.,ANU Medical School, The Australian National University, Canberra, ACT, Australia
| | - Nicholas J Hudson
- School of Agriculture and Food Sciences, The University of Queensland, St Lucia, QLD, Australia
| | - Scott C Cutmore
- School of Biological Sciences, The University of Queensland, St Lucia, QLD, Australia
| | - Wayne I L Davies
- Umeå Centre for Molecular Medicine (UCMM), Umeå University, Umeå, Sweden
| | - Shaun P Collin
- School of Life Sciences, La Trobe University, Bundoora, VIC, Australia
| | - David M Hunt
- School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia.,Centre for Ophthalmology and Visual Science, Lions Eye Institute, The University of Western Australia, Crawley, WA, Australia
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10
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Kelly ML, Spreitzenbarth S, Kerr CC, Hemmi JM, Lesku JA, Radford CA, Collin SP. Behavioural sleep in two species of buccal pumping sharks (Heterodontus portusjacksoni and Cephaloscyllium isabellum). J Sleep Res 2020; 30:e13139. [PMID: 32672393 DOI: 10.1111/jsr.13139] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 11/28/2022]
Abstract
Sleep is known to occur in most, if not all, animals studied thus far. Recent studies demonstrate the presence of sleep in flatworms and jellyfish, suggesting that this behaviour evolved early in the evolution of animals. Sharks are the earliest known extant, jawed vertebrates and may play an important role in understanding the evolutionary history of sleep in vertebrates, and yet, it is unknown whether they sleep. The Port Jackson (Heterodontus portusjacksoni) and draughtsboard (Cephaloscyllium isabellum) sharks are both benthic, buccal pumping species and remain motionless for extended periods of time. Whether these periods of prolonged inactivity represent sleep or quiet wakefulness is unknown. A key criterion for separating sleep from other quiescent states is an increased arousal threshold. We show here that inactive sharks of both species require significantly higher levels of electric stimulation before they show a visible response. Sharks deprived of rest, however, show no significant compensatory increase in restfulness during their normal active period following enforced swimming. Nonetheless, increased arousal thresholds in inactive animals suggest that these two species of shark sleep - the first such demonstration for members of this group of vertebrates. Further research, including electrophysiological studies, on these and other sharks, is required for a comprehensive understanding of sleep in cartilaginous fishes.
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Affiliation(s)
- Michael L Kelly
- School of Biological Sciences, The University of Western Australia, Perth, Australia.,Oceans Institute, The University of Western Australia, Perth, Australia.,Oceans Graduate School, The University of Western Australia, Perth, Australia
| | - Stefan Spreitzenbarth
- Leigh Marine Laboratory, Institute of Marine Science, The University of Auckland, Auckland, New Zealand
| | - Caroline C Kerr
- School of Life Sciences, La Trobe University, Melbourne, Australia
| | - Jan M Hemmi
- School of Biological Sciences, The University of Western Australia, Perth, Australia.,Oceans Institute, The University of Western Australia, Perth, Australia
| | - John A Lesku
- School of Life Sciences, La Trobe University, Melbourne, Australia
| | - Craig A Radford
- Leigh Marine Laboratory, Institute of Marine Science, The University of Auckland, Auckland, New Zealand
| | - Shaun P Collin
- Oceans Institute, The University of Western Australia, Perth, Australia.,Oceans Graduate School, The University of Western Australia, Perth, Australia.,School of Life Sciences, La Trobe University, Melbourne, Australia
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11
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Simões BF, Gower DJ, Rasmussen AR, Sarker MAR, Fry GC, Casewell NR, Harrison RA, Hart NS, Partridge JC, Hunt DM, Chang BS, Pisani D, Sanders KL. Spectral Diversification and Trans-Species Allelic Polymorphism during the Land-to-Sea Transition in Snakes. Curr Biol 2020; 30:2608-2615.e4. [PMID: 32470360 DOI: 10.1016/j.cub.2020.04.061] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 03/05/2020] [Accepted: 04/23/2020] [Indexed: 11/16/2022]
Abstract
Snakes are descended from highly visual lizards [1] but have limited (probably dichromatic) color vision attributed to a dim-light lifestyle of early snakes [2-4]. The living species of front-fanged elapids, however, are ecologically very diverse, with ∼300 terrestrial species (cobras, taipans, etc.) and ∼60 fully marine sea snakes, plus eight independently marine, amphibious sea kraits [1]. Here, we investigate the evolution of spectral sensitivity in elapids by analyzing their opsin genes (which are responsible for sensitivity to UV and visible light), retinal photoreceptors, and ocular lenses. We found that sea snakes underwent rapid adaptive diversification of their visual pigments when compared with their terrestrial and amphibious relatives. The three opsins present in snakes (SWS1, LWS, and RH1) have evolved under positive selection in elapids, and in sea snakes they have undergone multiple shifts in spectral sensitivity toward the longer wavelengths that dominate below the sea surface. Several relatively distantly related Hydrophis sea snakes are polymorphic for shortwave sensitive visual pigment encoded by alleles of SWS1. This spectral site polymorphism is expected to confer expanded "UV-blue" spectral sensitivity and is estimated to have persisted twice as long as the predicted survival time for selectively neutral nuclear alleles. We suggest that this polymorphism is adaptively maintained across Hydrophis species via balancing selection, similarly to the LWS polymorphism that confers allelic trichromacy in some primates. Diving sea snakes thus appear to share parallel mechanisms of color vision diversification with fruit-eating primates.
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Affiliation(s)
- Bruno F Simões
- University of Plymouth, School of Biological and Marine Sciences, Drake Circus, Plymouth PL4 8AA, United Kingdom; University of Bristol, School of Biological Sciences and School of Earth Sciences, Tyndall Avenue, Bristol BS8 1TG, United Kingdom; The University of Adelaide, School of Biological Sciences, North Terrace, Adelaide, South Australia 5005, Australia.
| | - David J Gower
- Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom
| | - Arne R Rasmussen
- The Royal Danish Academy of Fine Arts, School of Architecture, Design and Conservation, Philip de Langes Allé, 1435 Copenhagen K, Denmark
| | - Mohammad A R Sarker
- University of Dhaka, Department of Zoology, Curzon Hall Campus, Dhaka 1000, Bangladesh
| | - Gary C Fry
- CSIRO Oceans and Atmosphere, Queensland Biosciences Precinct, St Lucia, Queensland 4072, Australia
| | - Nicholas R Casewell
- Liverpool School of Tropical Medicine, Centre for Snakebite Research & Interventions, Pembroke Place, Liverpool L3 5QA, United Kingdom
| | - Robert A Harrison
- Liverpool School of Tropical Medicine, Centre for Snakebite Research & Interventions, Pembroke Place, Liverpool L3 5QA, United Kingdom
| | - Nathan S Hart
- Macquarie University, Department of Biological Sciences, North Ryde, Sydney, New South Wales 2109, Australia
| | - Julian C Partridge
- The University of Western Australia, Oceans Institute, Crawley, Perth, Western Australia 6009, Australia
| | - David M Hunt
- The University of Western Australia, School of Biological Sciences, Crawley, Perth, Western Australia 6009, Australia; The Lions Eye Institute, Centre for Ophthalmology and Visual Science, Nedlands, Perth, Western Australia 6009, Australia
| | - Belinda S Chang
- University of Toronto, Departments of Ecology & Evolutionary, Cell & Systems Biology, Willcocks Street, Toronto M5S 3G5, Canada
| | - Davide Pisani
- University of Bristol, School of Biological Sciences and School of Earth Sciences, Tyndall Avenue, Bristol BS8 1TG, United Kingdom
| | - Kate L Sanders
- The University of Adelaide, School of Biological Sciences, North Terrace, Adelaide, South Australia 5005, Australia; Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom
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12
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Kelly ML, Murray ERP, Kerr CC, Radford CA, Collin SP, Lesku JA, Hemmi JM. Diverse Activity Rhythms in Sharks (Elasmobranchii). J Biol Rhythms 2020; 35:476-488. [PMID: 32525441 DOI: 10.1177/0748730420932066] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Sharks are an interesting group of vertebrates, as many species swim continuously to "ram" oxygen-rich seawater over their gills (ram ventilators), whereas other species "pump" seawater over their gills by manipulating buccal cavity volume while remaining motionless (buccal pumpers). This difference in respiratory physiology raises the question: What are the implications of these differences in lifestyle for circadian rhythms? We investigated the diel activity patterns of 5 species of sharks, including 3 ram ventilating species: the school shark (Galeorhinus galeus), the spotted estuary smooth-hound (Mustelus lenticulatus), and the spiny dogfish (Squalus acanthias); and 2 buccal pumping species: the Port Jackson (Heterodontus portusjacksoni) and draughtsboard (Cephaloscyllium isabellum) sharks. We measured the amount, duration, and distance traveled while swimming over multiple days under a 12:12 light:dark light regime for all species and used modified light regimes for species with a clear diel rhythm in activity. We identified a surprising diversity of activity rhythms. The school shark and smooth-hound swam continuously; however, whereas the school shark swam at the same speed and covered the same distance during the day and night, the smooth-hound swam slower at night and traversed a shorter distance. A similar pattern was observed in the spiny dogfish, although this shark swam less overall. Both the Port Jackson and draughtsboard sharks showed a marked nocturnal preference for swimming. This pattern was muted and disrupted during constant light and constant dark regimes, although circadian organization of this pattern was maintained under certain conditions. The consequences of these patterns for other biological processes, such as sleep, remain unclear. Nonetheless, these 5 species demonstrate remarkable diversity within the activity rhythms of sharks.
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Affiliation(s)
- Michael L Kelly
- School of Biological Sciences, The University of Western Australia, Perth, Australia.,Oceans Institute, The University of Western Australia, Perth, Australia.,Oceans Graduate School, The University of Western Australia, Perth, Australia
| | - Errol R P Murray
- Institute of Marine Science, Leigh Marine Laboratory, The University of Auckland, Auckland, New Zealand
| | - Caroline C Kerr
- School of Life Sciences, La Trobe University, Melbourne, Australia
| | - Craig A Radford
- Institute of Marine Science, Leigh Marine Laboratory, The University of Auckland, Auckland, New Zealand
| | - Shaun P Collin
- Oceans Institute, The University of Western Australia, Perth, Australia.,Oceans Graduate School, The University of Western Australia, Perth, Australia.,School of Life Sciences, La Trobe University, Melbourne, Australia
| | - John A Lesku
- School of Life Sciences, La Trobe University, Melbourne, Australia
| | - Jan M Hemmi
- School of Biological Sciences, The University of Western Australia, Perth, Australia.,Oceans Institute, The University of Western Australia, Perth, Australia
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13
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Vision in sharks and rays: Opsin diversity and colour vision. Semin Cell Dev Biol 2020; 106:12-19. [PMID: 32331993 DOI: 10.1016/j.semcdb.2020.03.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 03/31/2020] [Accepted: 03/31/2020] [Indexed: 01/11/2023]
Abstract
The visual sense of elasmobranch fishes is poorly studied compared to their bony cousins, the teleosts. Nevertheless, the elasmobranch eye features numerous specialisations that have no doubt facilitated the diversification and evolutionary success of this fascinating taxon. In this review, I highlight recent discoveries on the nature and phylogenetic distribution of visual pigments in sharks and rays. Whereas most rays appear to be cone dichromats, all sharks studied to date are cone monochromats and, as a group, have likely abandoned colour vision on multiple occasions. This situation in sharks mirrors that seen in other large marine predators, the pinnipeds and cetaceans, which leads us to reassess the costs and benefits of multiple cone pigments and wavelength discrimination in the marine environment.
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14
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Peel LR, Collin SP, Hart NS. Retinal topography and spectral sensitivity of the Port Jackson shark (
Heterodontus portusjacksoni
). J Comp Neurol 2020; 528:2831-2847. [DOI: 10.1002/cne.24911] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/20/2020] [Accepted: 03/20/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Lauren R. Peel
- School of Biological Sciences University of Western Australia Crawley Western Australia Australia
- The Oceans Institute University of Western Australia Crawley Western Australia Australia
- The Oceans Graduate School University of Western Australia Crawley Western Australia Australia
| | - Shaun P. Collin
- School of Biological Sciences University of Western Australia Crawley Western Australia Australia
- The Oceans Institute University of Western Australia Crawley Western Australia Australia
- The Oceans Graduate School University of Western Australia Crawley Western Australia Australia
- School of Life Sciences, La Trobe University Bundoora Victoria Australia
| | - Nathan S. Hart
- School of Biological Sciences University of Western Australia Crawley Western Australia Australia
- Department of Biological Sciences Macquarie University Sydney New South Wales Australia
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15
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The retinal pigments of the whale shark ( Rhincodon typus) and their role in visual foraging ecology. Vis Neurosci 2019; 36:E011. [PMID: 31718726 DOI: 10.1017/s0952523819000105] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The spectral tuning properties of the whale shark (Rhincodon typus) rod (rhodopsin or Rh1) and long-wavelength-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 genomes have identified orthologous genes for both the whale shark Rh1 and LWS cone opsins suggesting a duplex retina. Here, the whale shark Rh1 and LWS cone opsin sequences were examined to identify amino acid residues critical for spectral tuning. Surprisingly, the predicted absorbance maximum (λmax) for both the whale shark Rh1 and LWS visual pigments is near 500 nm. Although Rh1 λmax values near 500 nm are typical of terrestrial vertebrates, as well as surface foraging fish, it is uncommon for a vertebrate LWS cone pigment to be so greatly blue-shifted. We propose that the spectral tuning properties of both the whale shark Rh1 and LWS cone pigments are most likely adaptations to the broadband light spectrum available at the surface. Whale shark melanopsin (Opn4) deactivation kinetics was examined to better understand the underlying molecular mechanisms of the pupillary light reflex. Results show that the deactivation rate of whale shark Opn4 is similar to the Opn4 deactivation rate from vertebrates possessing duplex retinae and is significantly faster than the Opn4 deactivation rate from an aquatic rod monochromat lacking functional cone photoreceptors. The rapid deactivation rate of whale shark Opn4 is consistent with a functional cone class and would provide the animal with an exponential increase in the number of photons required for photoreceptor signaling when transitioning from photopic to scotopic light conditions, as is the case when diving.
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16
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A detailed investigation of the visual system and visual ecology of the Barrier Reef anemonefish, Amphiprion akindynos. Sci Rep 2019; 9:16459. [PMID: 31712572 PMCID: PMC6848076 DOI: 10.1038/s41598-019-52297-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 10/13/2019] [Indexed: 11/24/2022] Open
Abstract
Vision plays a major role in the life of most teleosts, and is assumingly well adapted to each species ecology and behaviour. Using a multidisciplinary approach, we scrutinised several aspects of the visual system and ecology of the Great Barrier Reef anemonefish, Amphiprion akindynos, including its orange with white patterning, retinal anatomy and molecular biology, its symbiosis with anemones and sequential hermaphroditism. Amphiprion akindynos possesses spectrally distinct visual pigments and opsins: one rod opsin, RH1 (498 nm), and five cone opsins, SWS1 (370 nm), SWS2B (408 nm), RH2B (498 nm), RH2A (520 nm), and LWS (554 nm). Cones were arranged in a regular mosaic with each single cone surrounded by four double cones. Double cones mainly expressed RH2B (53%) in one member and RH2A (46%) in the other, matching the prevailing light. Single cones expressed SWS1 (89%), which may serve to detect zooplankton, conspecifics and the host anemone. Moreover, a segregated small fraction of single cones coexpressed SWS1 with SWS2B (11%). This novel visual specialisation falls within the region of highest acuity and is suggested to increase the chromatic contrast of Amphiprion akindynos colour patterns, which might improve detection of conspecifics.
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17
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Collin SP. Scene through the eyes of an apex predator: a comparative analysis of the shark visual system. Clin Exp Optom 2018; 101:624-640. [PMID: 30066959 DOI: 10.1111/cxo.12823] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 07/09/2018] [Accepted: 07/09/2018] [Indexed: 12/15/2022] Open
Abstract
The eyes of apex predators, such as the shark, have fascinated comparative visual neuroscientists for hundreds of years with respect to how they perceive the dark depths of their ocean realm or the visual scene in search of prey. As the earliest representatives of the first stage in the evolution of jawed vertebrates, sharks have an important role to play in our understanding of the evolution of the vertebrate eye, including that of humans. This comprehensive review covers the structure and function of all the major ocular components in sharks and how they are adapted to a range of underwater light environments. A comparative approach is used to identify: species-specific diversity in the perception of clear optical images; photoreception for various visual behaviours; the trade-off between image resolution and sensitivity; and visual processing under a range of levels of illumination. The application of this knowledge is also discussed with respect to the conservation of this important group of cartilaginous fishes.
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Affiliation(s)
- Shaun P Collin
- The Oceans Institute and the Oceans Graduate School, The University of Western Australia, Perth, Western Australia, Australia
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18
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Food approach conditioning and discrimination learning using sound cues in benthic sharks. Anim Cogn 2018; 21:481-492. [DOI: 10.1007/s10071-018-1183-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 04/05/2018] [Accepted: 04/21/2018] [Indexed: 12/27/2022]
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19
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Hart NS, Mountford JK, Davies WIL, Collin SP, Hunt DM. Visual pigments in a palaeognath bird, the emu Dromaius novaehollandiae: implications for spectral sensitivity and the origin of ultraviolet vision. Proc Biol Sci 2017; 283:rspb.2016.1063. [PMID: 27383819 DOI: 10.1098/rspb.2016.1063] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Accepted: 06/14/2016] [Indexed: 11/12/2022] Open
Abstract
A comprehensive description of the spectral characteristics of retinal photoreceptors in palaeognaths is lacking. Moreover, controversy exists with respect to the spectral sensitivity of the short-wavelength-sensitive-1 (SWS1) opsin-based visual pigment expressed in one type of single cone: previous microspectrophotometric (MSP) measurements in the ostrich (Struthio camelus) suggested a violet-sensitive (VS) SWS1 pigment, but all palaeognath SWS1 opsin sequences obtained to date (including the ostrich) imply that the visual pigment is ultraviolet-sensitive (UVS). In this study, MSP was used to measure the spectral properties of visual pigments and oil droplets in the retinal photoreceptors of the emu (Dromaius novaehollandiae). Results show that the emu resembles most other bird species in possessing four spectrally distinct single cones, as well as double cones and rods. Four cone and a single rod opsin are expressed, each an orthologue of a previously identified pigment. The SWS1 pigment is clearly UVS (wavelength of maximum absorbance [λmax] = 376 nm), with key tuning sites (Phe86 and Cys90) consistent with other vertebrate UVS SWS1 pigments. Palaeognaths would appear, therefore, to have UVS SWS1 pigments. As they are considered to be basal in avian evolution, this suggests that UVS is the most likely ancestral state for birds. The functional significance of a dedicated UVS cone type in the emu is discussed.
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Affiliation(s)
- Nathan S Hart
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia School of Animal Biology, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Jessica K Mountford
- School of Animal Biology, University of Western Australia, Crawley, Western Australia 6009, Australia Oceans Institute, University of Western Australia, Crawley, Western Australia 6009, Australia Lions Eye Institute, University of Western Australia, Nedlands, Western Australia 6009, Australia
| | - Wayne I L Davies
- School of Animal Biology, University of Western Australia, Crawley, Western Australia 6009, Australia Oceans Institute, University of Western Australia, Crawley, Western Australia 6009, Australia Lions Eye Institute, University of Western Australia, Nedlands, Western Australia 6009, Australia
| | - Shaun P Collin
- School of Animal Biology, University of Western Australia, Crawley, Western Australia 6009, Australia Oceans Institute, University of Western Australia, Crawley, Western Australia 6009, Australia Lions Eye Institute, University of Western Australia, Nedlands, Western Australia 6009, Australia
| | - David M Hunt
- School of Animal Biology, University of Western Australia, Crawley, Western Australia 6009, Australia Lions Eye Institute, University of Western Australia, Nedlands, Western Australia 6009, Australia
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20
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Jacobs GH. Photopigments and the dimensionality of animal color vision. Neurosci Biobehav Rev 2017; 86:108-130. [PMID: 29224775 DOI: 10.1016/j.neubiorev.2017.12.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/04/2017] [Accepted: 12/05/2017] [Indexed: 12/31/2022]
Abstract
Early color-matching studies established that normal human color vision is trichromatic. Subsequent research revealed a causal link between trichromacy and the presence in the retina of three classes of cone photopigments. Over the years, measurements of the photopigment complements of other species have expanded greatly and these are frequently used to predict the dimensionality of an animal's color vision. This review provides an account of how the linkage between the number of active photopigments and the dimensions of human color vision developed, summarizes the various mechanisms that can impact photopigment spectra and number, and provides an across-species survey to examine cases where the photopigment link to the dimensionality of color vision has been claimed. The literature reveals numerous instances where the human model fails to account for the ways in which the visual systems of other animals exploit information obtained from the presence of multiple photopigments in support of their behavior.
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Affiliation(s)
- Gerald H Jacobs
- Department of Psychological and Brain Science, University of California, Santa Barbara, CA 93106, USA.
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21
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Musser JM, Arendt D. Loss and gain of cone types in vertebrate ciliary photoreceptor evolution. Dev Biol 2017; 431:26-35. [DOI: 10.1016/j.ydbio.2017.08.038] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Revised: 08/28/2017] [Accepted: 08/30/2017] [Indexed: 01/09/2023]
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22
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The Ebbinghaus illusion in the gray bamboo shark (Chiloscyllium griseum) in comparison to the teleost damselfish (Chromis chromis). ZOOLOGY 2017; 123:16-29. [PMID: 28712674 DOI: 10.1016/j.zool.2017.05.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 05/18/2017] [Accepted: 05/18/2017] [Indexed: 11/22/2022]
Abstract
This is the first study to comparatively assess the perception of the Ebbinghaus-Titchener circles and variations of the Delboeuf illusion in four juvenile bamboo sharks (Chiloscyllium griseum) and five damselfish (Chromis chromis) using identical training paradigms. We aimed to investigate whether these two species show similarities in the perceptual integration of local elements into the global context. The Ebbinghaus-Titchener circles consist of two equally sized central test circles surrounded by smaller or larger circles of different size, number and/or distance. During training, sharks and damselfish learned to distinguish a large circle from a small circle, regardless (i) of its gray level and (ii) of the presence of surrounding circles arranged along an outer semi-circle. During the subsequent transfer period, individuals were presented with variations of the Ebbinghaus-Titchener circles and the Delboeuf illusion. Similar to adult humans, dolphins, or some birds, damselfish tended to judge the test circle surrounded by smaller inducers as larger than the one surrounded by larger inducers (contrast effect). However, sharks significantly preferred the overall larger figure or chose indifferently between both alternatives (assimilation effect). These contrasting responses point towards potential differences in perceptual processing mechanisms, such as 'filling-in' or '(a)modal completion', 'perceptual grouping', and 'local' or 'global' visual perception. The present study provides intriguing insights into the perceptual abilities of phylogenetically distant taxa separated in evolutionary time by 200 million years.
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23
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Electrophysiological measures of temporal resolution, contrast sensitivity and spatial resolving power in sharks. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:197-210. [DOI: 10.1007/s00359-017-1154-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 02/05/2017] [Accepted: 02/07/2017] [Indexed: 02/07/2023]
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24
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Bedore CN, Kajiura SM, Johnsen S. Freezing behaviour facilitates bioelectric crypsis in cuttlefish faced with predation risk. Proc Biol Sci 2017; 282:20151886. [PMID: 26631562 DOI: 10.1098/rspb.2015.1886] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cephalopods, and in particular the cuttlefish Sepia officinalis, are common models for studies of camouflage and predator avoidance behaviour. Preventing detection by predators is especially important to this group of animals, most of which are soft-bodied, lack physical defences, and are subject to both visually and non-visually mediated detection. Here, we report a novel cryptic mechanism in S. officinalis in which bioelectric cues are reduced via a behavioural freeze response to a predator stimulus. The reduction of bioelectric fields created by the freeze-simulating stimulus resulted in a possible decrease in shark predation risk by reducing detectability. The freeze response may also facilitate other non-visual cryptic mechanisms to lower predation risk from a wide range of predator types.
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Affiliation(s)
| | - Stephen M Kajiura
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Sönke Johnsen
- Biology Department, Duke University, Durham, NC 27708, USA
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25
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Ryan LA, Hart NS, Collin SP, Hemmi JM. Visual resolution and contrast sensitivity in two benthic sharks. ACTA ACUST UNITED AC 2016; 219:3971-3980. [PMID: 27802139 DOI: 10.1242/jeb.132100] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 10/11/2016] [Indexed: 12/25/2022]
Abstract
Sharks have long been described as having 'poor' vision. They are cone monochromats and anatomical estimates suggest they have low spatial resolution. However, there are no direct behavioural measurements of spatial resolution or contrast sensitivity. This study estimates contrast sensitivity and spatial resolution of two species of benthic sharks, the Port Jackson shark, Heterodontus portusjacksoni, and the brown-banded bamboo shark, Chiloscyllium punctatum, by recording eye movements in response to optokinetic stimuli. Both species tracked moving low spatial frequency gratings with weak but consistent eye movements. Eye movements ceased at 0.38 cycles per degree, even for high contrasts, suggesting low spatial resolution. However, at lower spatial frequencies, eye movements were elicited by low contrast gratings, 1.3% and 2.9% contrast in H portusjacksoni and C. punctatum, respectively. Contrast sensitivity was higher than in other vertebrates with a similar spatial resolving power, which may reflect an adaptation to the relatively low contrast encountered in aquatic environments. Optokinetic gain was consistently low and neither species stabilised the gratings on their retina. To check whether restraining the animals affected their optokinetic responses, we also analysed eye movements in free-swimming C. punctatum We found no eye movements that could compensate for body rotations, suggesting that vision may pass through phases of stabilisation and blur during swimming. As C. punctatum is a sedentary benthic species, gaze stabilisation during swimming may not be essential. Our results suggest that vision in sharks is not 'poor' as previously suggested, but optimised for contrast detection rather than spatial resolution.
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Affiliation(s)
- Laura A Ryan
- School of Animal Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia .,The UWA Oceans Institute, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Nathan S Hart
- School of Animal Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.,The UWA Oceans Institute, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.,Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Shaun P Collin
- School of Animal Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.,The UWA Oceans Institute, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Jan M Hemmi
- School of Animal Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.,The UWA Oceans Institute, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
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26
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Nagloo N, Collin SP, Hemmi JM, Hart NS. Spatial resolving power and spectral sensitivity of the saltwater crocodile, Crocodylus porosus, and the freshwater crocodile, Crocodylus johnstoni. J Exp Biol 2016; 219:1394-404. [DOI: 10.1242/jeb.135673] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 02/23/2016] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Crocodilians are apex amphibious predators that occupy a range of tropical habitats. In this study, we examined whether their semi-aquatic lifestyle and ambush hunting mode are reflected in specific adaptations in the peripheral visual system. Design-based stereology and microspectrophotometry were used to assess spatial resolving power and spectral sensitivity of saltwater (Crocodylus porosus) and freshwater crocodiles (Crocodylus johnstoni). Both species possess a foveal streak that spans the naso-temporal axis and mediates high spatial acuity across the central visual field. The saltwater crocodile and freshwater crocodile have a peak spatial resolving power of 8.8 and 8.0 cycles deg−1, respectively. Measurement of the outer segment dimensions and spectral absorbance revealed five distinct photoreceptor types consisting of three single cones, one twin cone and a rod. The three single cones (saltwater/freshwater crocodile) are violet (424/426 nm λmax), green (502/510 nm λmax) and red (546/554 nm λmax) sensitive, indicating the potential for trichromatic colour vision. The visual pigments of both members of the twin cones have the same λmax as the red-sensitive single cone and the rod has a λmax at 503/510 nm (saltwater/freshwater). The λmax values of all types of visual pigment occur at longer wavelengths in the freshwater crocodile compared with the saltwater crocodile. Given that there is a greater abundance of long wavelength light in freshwater compared with a saltwater environment, the photoreceptors would be more effective at detecting light in their respective habitats. This suggests that the visual systems of both species are adapted to the photic conditions of their respective ecological niche.
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Affiliation(s)
- Nicolas Nagloo
- School of Animal Biology, The University of Western Australia, Crawley, Western Australia 6009, Australia
- The Oceans Institute, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Shaun P. Collin
- School of Animal Biology, The University of Western Australia, Crawley, Western Australia 6009, Australia
- The Oceans Institute, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Jan M. Hemmi
- School of Animal Biology, The University of Western Australia, Crawley, Western Australia 6009, Australia
- The Oceans Institute, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Nathan S. Hart
- School of Animal Biology, The University of Western Australia, Crawley, Western Australia 6009, Australia
- The Oceans Institute, The University of Western Australia, Crawley, Western Australia 6009, Australia
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia
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27
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Gruber DF, Loew ER, Deheyn DD, Akkaynak D, Gaffney JP, Smith WL, Davis MP, Stern JH, Pieribone VA, Sparks JS. Biofluorescence in Catsharks (Scyliorhinidae): Fundamental Description and Relevance for Elasmobranch Visual Ecology. Sci Rep 2016; 6:24751. [PMID: 27109385 PMCID: PMC4843165 DOI: 10.1038/srep24751] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 04/05/2016] [Indexed: 01/01/2023] Open
Abstract
Biofluorescence has recently been found to be widespread in marine fishes, including sharks. Catsharks, such as the Swell Shark (Cephaloscyllium ventriosum) from the eastern Pacific and the Chain Catshark (Scyliorhinus retifer) from the western Atlantic, are known to exhibit bright green fluorescence. We examined the spectral sensitivity and visual characteristics of these reclusive sharks, while also considering the fluorescent properties of their skin. Spectral absorbance of the photoreceptor cells in these sharks revealed the presence of a single visual pigment in each species. Cephaloscyllium ventriosum exhibited a maximum absorbance of 484 ± 3 nm and an absorbance range at half maximum (λ1/2max) of 440-540 nm, whereas for S. retifer maximum absorbance was 488 ± 3 nm with the same absorbance range. Using the photoreceptor properties derived here, a "shark eye" camera was designed and developed that yielded contrast information on areas where fluorescence is anatomically distributed on the shark, as seen from other sharks' eyes of these two species. Phylogenetic investigations indicate that biofluorescence has evolved at least three times in cartilaginous fishes. The repeated evolution of biofluorescence in elasmobranchs, coupled with a visual adaptation to detect it; and evidence that biofluorescence creates greater luminosity contrast with the surrounding background, highlights the potential importance of biofluorescence in elasmobranch behavior and biology.
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Affiliation(s)
- David F. Gruber
- Baruch College, City University of New York, Department of Natural Sciences, New York, NY 10010, USA
- City University of New York, The Graduate Center, Program in Biology, New York, NY 10016, USA
- American Museum of Natural History, Sackler Institute for Comparative Genomics, New York, NY 10024, USA
| | - Ellis R. Loew
- College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Dimitri D. Deheyn
- University of California, San Diego, Scripps Institution of Oceanography, La Jolla, CA 92093, USA
| | - Derya Akkaynak
- University of Haifa, Charney School of Marine Sciences, Haifa, 3498838, Israel
- Interuniversity Institute of Marine Sciences, Eilat, 88103, Israel
| | - Jean P. Gaffney
- Baruch College, City University of New York, Department of Natural Sciences, New York, NY 10010, USA
| | - W. Leo Smith
- University of Kansas, Biodiversity Institute and Department of Ecology and Evolutionary Biology, Lawrence, KS 66049, USA
| | - Matthew P. Davis
- St. Cloud State University, Department of Biological Sciences, St. Cloud, MN 56301, USA
| | - Jennifer H. Stern
- University of Kansas, Biodiversity Institute and Department of Ecology and Evolutionary Biology, Lawrence, KS 66049, USA
| | - Vincent A. Pieribone
- The John B. Pierce Laboratory, Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06519, USA
| | - John S. Sparks
- American Museum of Natural History, Sackler Institute for Comparative Genomics, New York, NY 10024, USA
- American Museum of Natural History, Division of Vertebrate Zoology, Department of Ichthyology, New York, NY 10024, USA
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Gerlach T, Theobald J, Hart NS, Collin SP, Michiels NK. Fluorescence characterisation and visual ecology of pseudocheilinid wrasses. Front Zool 2016; 13:13. [PMID: 26981144 PMCID: PMC4791940 DOI: 10.1186/s12983-016-0145-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/09/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Wrasses represent the second largest family of marine fishes and display a high diversity of complex colours linked to ecological functions. Recently, red autofluorescent body colouration has been reported in some of these fishes. However, little is known about the distribution of such fluorescent body patterns in wrasses or the animals' ability to perceive such colours. RESULTS Against this background, we (1) investigated long-wavelength emission autofluorescence in thirteen species of pseudocheilinid wrasses and (2) characterised the spectral absorbance of visual pigments in one of the examined species, the fairy wrasse Cirrhilabrus solorensis. Spectrophotometric analysis revealed that fluorescent body colouration is widespread and diverse within this clade, with considerable variation in both fluorescent pattern and maximum emission wavelength between species. Characterisation of visual pigments in retinal photoreceptors showed a single class of rod and three spectrally distinct cone photoreceptors, suggesting possible trichromacy. CONCLUSION Combining the emission characteristics of fluorescence body colouration and the spectral sensitivity data of retinal cells suggests that the visual system of C. solorensis is sensitive to pseudocheilinid fluorescence.
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Affiliation(s)
- Tobias Gerlach
- Animal Evolutionary Ecology group, Faculty of Sciences, University of Tübingen, Tübingen, Germany
| | - Jennifer Theobald
- Animal Evolutionary Ecology group, Faculty of Sciences, University of Tübingen, Tübingen, Germany
| | - Nathan S Hart
- School of Animal Biology and The Oceans Institute, The University of Western Australia, Perth, Australia
| | - Shaun P Collin
- School of Animal Biology and The Oceans Institute, The University of Western Australia, Perth, Australia
| | - Nico K Michiels
- Animal Evolutionary Ecology group, Faculty of Sciences, University of Tübingen, Tübingen, Germany
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Nosal AP, Chao Y, Farrara JD, Chai F, Hastings PA. Olfaction Contributes to Pelagic Navigation in a Coastal Shark. PLoS One 2016; 11:e0143758. [PMID: 26735492 PMCID: PMC4703295 DOI: 10.1371/journal.pone.0143758] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 11/09/2015] [Indexed: 11/19/2022] Open
Abstract
How animals navigate the constantly moving and visually uniform pelagic realm, often along straight paths between distant sites, is an enduring mystery. The mechanisms enabling pelagic navigation in cartilaginous fishes are particularly understudied. We used shoreward navigation by leopard sharks (Triakis semifasciata) as a model system to test whether olfaction contributes to pelagic navigation. Leopard sharks were captured alongshore, transported 9 km offshore, released, and acoustically tracked for approximately 4 h each until the transmitter released. Eleven sharks were rendered anosmic (nares occluded with cotton wool soaked in petroleum jelly); fifteen were sham controls. Mean swimming depth was 28.7 m. On average, tracks of control sharks ended 62.6% closer to shore, following relatively straight paths that were significantly directed over spatial scales exceeding 1600 m. In contrast, tracks of anosmic sharks ended 37.2% closer to shore, following significantly more tortuous paths that approximated correlated random walks. These results held after swimming paths were adjusted for current drift. This is the first study to demonstrate experimentally that olfaction contributes to pelagic navigation in sharks, likely mediated by chemical gradients as has been hypothesized for birds. Given the similarities between the fluid three-dimensional chemical atmosphere and ocean, further research comparing swimming and flying animals may lead to a unifying paradigm explaining their extraordinary navigational abilities.
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Affiliation(s)
- Andrew P. Nosal
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92037, United States of America
| | - Yi Chao
- Department of Atmospheric and Oceanic Sciences and Joint Institute for Regional Earth System Science and Engineering, University of California Los Angeles, Los Angeles, California, 90095, United States of America
| | - John D. Farrara
- Department of Atmospheric and Oceanic Sciences and Joint Institute for Regional Earth System Science and Engineering, University of California Los Angeles, Los Angeles, California, 90095, United States of America
| | - Fei Chai
- School of Marine Sciences, University of Maine, Orono, Maine, 04469, United States of America
| | - Philip A. Hastings
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92037, United States of America
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Cortesi F, Musilová Z, Stieb SM, Hart NS, Siebeck UE, Cheney KL, Salzburger W, Marshall NJ. From crypsis to mimicry: changes in colour and the configuration of the visual system during ontogenetic habitat transitions in a coral reef fish. J Exp Biol 2016; 219:2545-58. [DOI: 10.1242/jeb.139501] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 06/09/2016] [Indexed: 01/30/2023]
Abstract
Animals often change their habitat throughout ontogeny; yet, the triggers for habitat transitions and how these correlate with developmental changes – e.g. physiological, morphological, and behavioural – remain largely unknown. Here, we investigated how ontogenetic changes in body colouration and of the visual system relate to habitat transitions in a coral-reef fish. Adult dusky dottybacks, Pseudochromis fuscus, are aggressive mimics that change colour to imitate various fishes in their surroundings; however, little is known about the early life stages of this fish. Using a developmental time-series in combination with the examination of wild caught specimens we uncover that dottybacks change colour twice during development: (i) nearly translucent cryptic pelagic larvae change to a grey camouflage colouration when settling on coral reefs; and (ii) juveniles change to mimic yellow or brown coloured fishes when reaching a size capable of consuming juvenile fish prey. Moreover, microspectrophotometric (MSP) and quantitative real time PCR (qRT-PCR) experiments show developmental changes of the dottyback visual system, including the use of a novel adult specific visual gene (RH2 opsin). This gene is likely to be coexpressed with other visual pigments to form broad spectral sensitivities that cover the medium-wavelength part of the visible spectrum. Surprisingly, the visual modifications precede changes in habitat and colour, possibly because dottybacks need to first acquire the appropriate visual performance before transitioning into novel life stages.
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Affiliation(s)
- Fabio Cortesi
- Queensland Brain Institute, The University of Queensland, Brisbane 4072, Australia
- School of Biological Sciences, The University of Queensland, Brisbane 4072, Australia
- Zoological Institute, University of Basel, Basel 4051, Switzerland
| | - Zuzana Musilová
- Zoological Institute, University of Basel, Basel 4051, Switzerland
- Department of Zoology, Charles University in Prague, 128 44 Prague, Czech Republic
| | - Sara M. Stieb
- Queensland Brain Institute, The University of Queensland, Brisbane 4072, Australia
| | - Nathan S. Hart
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Ulrike E. Siebeck
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia
| | - Karen L. Cheney
- School of Biological Sciences, The University of Queensland, Brisbane 4072, Australia
| | - Walter Salzburger
- Zoological Institute, University of Basel, Basel 4051, Switzerland
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, Oslo 0316, Norway
| | - N. Justin Marshall
- Queensland Brain Institute, The University of Queensland, Brisbane 4072, Australia
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de Busserolles F, Hart NS, Hunt DM, Davies WI, Marshall NJ, Clarke MW, Hahne D, Collin SP. Spectral Tuning in the Eyes of Deep-Sea Lanternfishes (Myctophidae): A Novel Sexually Dimorphic Intra-Ocular Filter. BRAIN, BEHAVIOR AND EVOLUTION 2015; 85:77-93. [DOI: 10.1159/000371652] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 09/15/2014] [Indexed: 11/19/2022]
Abstract
Deep-sea fishes possess several adaptations to facilitate vision where light detection is pushed to its limit. Lanternfishes (Myctophidae), one of the world's most abundant groups of mesopelagic fishes, possess a novel and unique visual specialisation, a sexually dimorphic photostable yellow pigmentation, constituting the first record of a visual sexual dimorphism in any non-primate vertebrate. The topographic distribution of the yellow pigmentation across the retina is species specific, varying in location, shape and size. Spectrophotometric analyses reveal that this new retinal specialisation differs between species in terms of composition and acts as a filter, absorbing maximally between 356 and 443 nm. Microspectrophotometry and molecular analyses indicate that the species containing this pigmentation also possess at least 2 spectrally distinct rod visual pigments as a result of a duplication of the Rh1 opsin gene. After modelling the effect of the yellow pigmentation on photoreceptor spectral sensitivity, we suggest that this unique specialisation acts as a filter to enhance contrast, thereby improving the detection of bioluminescent emissions and possibly fluorescence in the extreme environment of the deep sea. The fact that this yellow pigmentation is species specific, sexually dimorphic and isolated within specific parts of the retina indicates an evolutionary pressure to visualise prey/predators/mates in a particular part of each species' visual field.
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COLLIN SP, HART NS. Vision and photoentrainment in fishes: The effects of natural and anthropogenic perturbation. Integr Zool 2015; 10:15-28. [DOI: 10.1111/1749-4877.12093] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Shaun P. COLLIN
- School of Animal Biology and the Oceans Institute; University of Western Australia; Crawley Western Australia Australia
| | - Nathan S. HART
- School of Animal Biology and the Oceans Institute; University of Western Australia; Crawley Western Australia Australia
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33
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Affiliation(s)
- Nathan S. HART
- School of Animal Biology and the Oceans Institute; The University of Western Australia; Crawley Perth Australia
| | - Shaun P. COLLIN
- School of Animal Biology and the Oceans Institute; The University of Western Australia; Crawley Perth Australia
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Ancestral duplications and highly dynamic opsin gene evolution in percomorph fishes. Proc Natl Acad Sci U S A 2014; 112:1493-8. [PMID: 25548152 DOI: 10.1073/pnas.1417803112] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Single-gene and whole-genome duplications are important evolutionary mechanisms that contribute to biological diversification by launching new genetic raw material. For example, the evolution of animal vision is tightly linked to the expansion of the opsin gene family encoding light-absorbing visual pigments. In teleost fishes, the most species-rich vertebrate group, opsins are particularly diverse and key to the successful colonization of habitats ranging from the bioluminescence-biased but basically dark deep sea to clear mountain streams. In this study, we report a previously unnoticed duplication of the violet-blue short wavelength-sensitive 2 (SWS2) opsin, which coincides with the radiation of highly diverse percomorph fishes, permitting us to reinterpret the evolution of this gene family. The inspection of close to 100 fish genomes revealed that, triggered by frequent gene conversion between duplicates, the evolutionary history of SWS2 is rather complex and difficult to predict. Coincidentally, we also report potential cases of gene resurrection in vertebrate opsins, whereby pseudogenized genes were found to convert with their functional paralogs. We then identify multiple novel amino acid substitutions that are likely to have contributed to the adaptive differentiation between SWS2 copies. Finally, using the dusky dottyback Pseudochromis fuscus, we show that the newly discovered SWS2A duplicates can contribute to visual adaptation in two ways: by gaining sensitivities to different wavelengths of light and by being differentially expressed between ontogenetic stages. Thus, our study highlights the importance of comparative approaches in gaining a comprehensive view of the dynamics underlying gene family evolution and ultimately, animal diversification.
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Spectral sensitivity, luminous sensitivity, and temporal resolution of the visual systems in three sympatric temperate coastal shark species. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 200:997-1013. [DOI: 10.1007/s00359-014-0950-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 09/23/2014] [Accepted: 10/01/2014] [Indexed: 01/04/2023]
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Schluessel V, Rick IP, Plischke K. No rainbow for grey bamboo sharks: evidence for the absence of colour vision in sharks from behavioural discrimination experiments. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 200:939-47. [DOI: 10.1007/s00359-014-0940-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 09/08/2014] [Accepted: 09/09/2014] [Indexed: 11/28/2022]
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Claes JM, Partridge JC, Hart NS, Garza-Gisholt E, Ho HC, Mallefet J, Collin SP. Photon hunting in the twilight zone: visual features of mesopelagic bioluminescent sharks. PLoS One 2014; 9:e104213. [PMID: 25099504 PMCID: PMC4123902 DOI: 10.1371/journal.pone.0104213] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 07/04/2014] [Indexed: 01/01/2023] Open
Abstract
The mesopelagic zone is a visual scene continuum in which organisms have developed various strategies to optimize photon capture. Here, we used light microscopy, stereology-assisted retinal topographic mapping, spectrophotometry and microspectrophotometry to investigate the visual ecology of deep-sea bioluminescent sharks [four etmopterid species (Etmopterus lucifer, E. splendidus, E. spinax and Trigonognathus kabeyai) and one dalatiid species (Squaliolus aliae)]. We highlighted a novel structure, a translucent area present in the upper eye orbit of Etmopteridae, which might be part of a reference system for counterillumination adjustment or acts as a spectral filter for camouflage breaking, as well as several ocular specialisations such as aphakic gaps and semicircular tapeta previously unknown in elasmobranchs. All species showed pure rod hexagonal mosaics with a high topographic diversity. Retinal specialisations, formed by shallow cell density gradients, may aid in prey detection and reflect lifestyle differences; pelagic species display areae centrales while benthopelagic and benthic species display wide and narrow horizontal streaks, respectively. One species (E. lucifer) displays two areae within its horizontal streak that likely allows detection of conspecifics' elongated bioluminescent flank markings. Ganglion cell topography reveals less variation with all species showing a temporal area for acute frontal binocular vision. This area is dorsally extended in T. kabeyai, allowing this species to adjust the strike of its peculiar jaws in the ventro-frontal visual field. Etmopterus lucifer showed an additional nasal area matching a high rod density area. Peak spectral sensitivities of the rod visual pigments (λmax) fall within the range 484–491 nm, allowing these sharks to detect a high proportion of photons present in their habitat. Comparisons with previously published data reveal ocular differences between bioluminescent and non-bioluminescent deep-sea sharks. In particular, bioluminescent sharks possess higher rod densities, which might provide them with improved temporal resolution particularly useful for bioluminescent communication during social interactions.
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Affiliation(s)
- Julien M. Claes
- Laboratoire de Biologie Marine, Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
- * E-mail:
| | - Julian C. Partridge
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
- Neuroecology Group, School of Animal Biology and the UWA Oceans Institute, The University of Western Australia, Crawley, Australia
| | - Nathan S. Hart
- Neuroecology Group, School of Animal Biology and the UWA Oceans Institute, The University of Western Australia, Crawley, Australia
| | - Eduardo Garza-Gisholt
- Neuroecology Group, School of Animal Biology and the UWA Oceans Institute, The University of Western Australia, Crawley, Australia
| | - Hsuan-Ching Ho
- National Museum of Marine Biology and Aquarium, Checheng, Taiwan
- Institute of Marine Biodiversity and Evolutionary Biology, National Dong Hwa University, Shoufeng, Taiwan
| | - Jérôme Mallefet
- Laboratoire de Biologie Marine, Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Shaun P. Collin
- Neuroecology Group, School of Animal Biology and the UWA Oceans Institute, The University of Western Australia, Crawley, Australia
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Schluessel V, Beil O, Weber T, Bleckmann H. Symmetry perception in bamboo sharks (Chiloscyllium griseum) and Malawi cichlids (Pseudotropheus sp.). Anim Cogn 2014; 17:1187-205. [DOI: 10.1007/s10071-014-0751-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 04/07/2014] [Accepted: 04/20/2014] [Indexed: 10/25/2022]
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Fuss T, Bleckmann H, Schluessel V. The brain creates illusions not just for us: sharks (Chiloscyllium griseum) can "see the magic" as well. Front Neural Circuits 2014; 8:24. [PMID: 24688458 PMCID: PMC3960505 DOI: 10.3389/fncir.2014.00024] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 03/03/2014] [Indexed: 01/17/2023] Open
Abstract
Bamboo sharks (Chiloscyllium griseum) were tested for their ability to perceive subjective and illusionary contours as well as line length illusions. Individuals were first trained to differentiate between squares, triangles, and rhomboids in a series of two alternative forced-choice experiments. Transfer tests then elucidated whether Kanizsa squares and triangles, grating gaps and phase shifted abutting gratings were also perceived and distinguished. The visual systems of most vertebrates and even invertebrates perceive illusionary contours despite the absence of physical luminance, color or textural differences. Sharks are no exception to the rule; all tasks were successfully mastered within 3-24 training sessions, with sharks discriminating between various sets of Kanizsa figures and alternative stimuli, as well as between subjective contours in >75% of all tests. However, in contrast to Kanizsa figures and subjective contours, sharks were not deceived by Müller-Lyer (ML) illusions. Here, two center lines of equal length are comparatively set between two arrowheads or -tails, in which case the line featuring the two arrow tails appears to be longer to most humans, primates and birds. In preparation for this experiment, lines of varying length, and lines of unequal length randomly featuring either two arrowheads or -tails on their ends, were presented first. Both sets of lines were successfully distinguished by most sharks. However, during presentation of the ML illusions sharks failed to succeed and succumbed either to side preferences or chose according to chance.
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Affiliation(s)
- Theodora Fuss
- Department for Comparative Sensory Biology and Neurobiology, Institute of Zoology, Rheinische Friedrich-Wilhelms-University Bonn Bonn, Germany
| | - Horst Bleckmann
- Department for Comparative Sensory Biology and Neurobiology, Institute of Zoology, Rheinische Friedrich-Wilhelms-University Bonn Bonn, Germany
| | - Vera Schluessel
- Department for Comparative Sensory Biology and Neurobiology, Institute of Zoology, Rheinische Friedrich-Wilhelms-University Bonn Bonn, Germany
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Yokoyama S, Starmer WT, Liu Y, Tada T, Britt L. Extraordinarily low evolutionary rates of short wavelength-sensitive opsin pseudogenes. Gene 2013; 534:93-9. [PMID: 24125953 DOI: 10.1016/j.gene.2013.09.114] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 09/24/2013] [Accepted: 09/26/2013] [Indexed: 01/08/2023]
Abstract
Aquatic organisms such as cichlids, coelacanths, seals, and cetaceans are active in UV-blue color environments, but many of them mysteriously lost their abilities to detect these colors. The loss of these functions is a consequence of the pseudogenization of their short wavelength-sensitive (SWS1) opsin genes without gene duplication. We show that the SWS1 gene (BdenS1ψ) of the deep-sea fish, pearleye (Benthalbella dentata), became a pseudogene in a similar fashion about 130 million years ago (Mya) yet it is still transcribed. The rates of nucleotide substitution (~1.4 × 10(-9)/site/year) of the pseudogenes of these aquatic species as well as some prosimian and bat species are much smaller than the previous estimates for the globin and immunoglobulin pseudogenes.
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Affiliation(s)
- Shozo Yokoyama
- Department of Biology, Emory University, Atlanta, GA 30322, USA.
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Bedore CN, Loew ER, Frank TM, Hueter RE, McComb DM, Kajiura SM. A physiological analysis of color vision in batoid elasmobranchs. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2013; 199:1129-41. [DOI: 10.1007/s00359-013-0855-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 08/18/2013] [Accepted: 09/11/2013] [Indexed: 11/30/2022]
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Abstract
AbstractS 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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Meredith RW, Gatesy J, Emerling CA, York VM, Springer MS. Rod monochromacy and the coevolution of cetacean retinal opsins. PLoS Genet 2013; 9:e1003432. [PMID: 23637615 PMCID: PMC3630094 DOI: 10.1371/journal.pgen.1003432] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 02/15/2013] [Indexed: 01/02/2023] Open
Abstract
Cetaceans have a long history of commitment to a fully aquatic lifestyle that extends back to the Eocene. Extant species have evolved a spectacular array of adaptations in conjunction with their deployment into a diverse array of aquatic habitats. Sensory systems are among those that have experienced radical transformations in the evolutionary history of this clade. In the case of vision, previous studies have demonstrated important changes in the genes encoding rod opsin (RH1), short-wavelength sensitive opsin 1 (SWS1), and long-wavelength sensitive opsin (LWS) in selected cetaceans, but have not examined the full complement of opsin genes across the complete range of cetacean families. Here, we report protein-coding sequences for RH1 and both color opsin genes (SWS1, LWS) from representatives of all extant cetacean families. We examine competing hypotheses pertaining to the timing of blue shifts in RH1 relative to SWS1 inactivation in the early history of Cetacea, and we test the hypothesis that some cetaceans are rod monochomats. Molecular evolutionary analyses contradict the "coastal" hypothesis, wherein SWS1 was pseudogenized in the common ancestor of Cetacea, and instead suggest that RH1 was blue-shifted in the common ancestor of Cetacea before SWS1 was independently knocked out in baleen whales (Mysticeti) and in toothed whales (Odontoceti). Further, molecular evidence implies that LWS was inactivated convergently on at least five occasions in Cetacea: (1) Balaenidae (bowhead and right whales), (2) Balaenopteroidea (rorquals plus gray whale), (3) Mesoplodon bidens (Sowerby's beaked whale), (4) Physeter macrocephalus (giant sperm whale), and (5) Kogia breviceps (pygmy sperm whale). All of these cetaceans are known to dive to depths of at least 100 m where the underwater light field is dim and dominated by blue light. The knockout of both SWS1 and LWS in multiple cetacean lineages renders these taxa rod monochromats, a condition previously unknown among mammalian species.
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Affiliation(s)
- Robert W. Meredith
- Department of Biology, University of California Riverside, Riverside, California, United States of America
- Department of Biology and Molecular Biology, Montclair State University, Montclair, New Jersey, United States of America
| | - John Gatesy
- Department of Biology, University of California Riverside, Riverside, California, United States of America
| | - Christopher A. Emerling
- Department of Biology, University of California Riverside, Riverside, California, United States of America
| | - Vincent M. York
- Department of Biology, University of California Riverside, Riverside, California, United States of America
- Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Mark S. Springer
- Department of Biology, University of California Riverside, Riverside, California, United States of America
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Jordan LK, Mandelman JW, McComb DM, Fordham SV, Carlson JK, Werner TB. Linking sensory biology and fisheries bycatch reduction in elasmobranch fishes: a review with new directions for research. CONSERVATION PHYSIOLOGY 2013; 1:cot002. [PMID: 27293586 PMCID: PMC4732448 DOI: 10.1093/conphys/cot002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 02/18/2013] [Accepted: 02/19/2013] [Indexed: 05/08/2023]
Abstract
Incidental capture, or bycatch, in fisheries represents a substantial threat to the sustainability of elasmobranch populations worldwide. Consequently, researchers are increasingly investigating elasmobranch bycatch reduction methods, including some focused on these species' sensory capabilities, particularly their electrosensory systems. To guide this research, we review current knowledge of elasmobranch sensory biology and feeding ecology with respect to fishing gear interactions and include examples of bycatch reduction methods used for elasmobranchs as well as other taxonomic groups. We discuss potential elasmobranch bycatch reduction strategies for various fishing gear types based on the morphological, physiological, and behavioural characteristics of species within this diverse group. In select examples, we indicate how an understanding of the physiology and sensory biology of vulnerable, bycatch-prone, non-target elasmobranch species can help in the identification of promising options for bycatch reduction. We encourage collaboration among researchers studying bycatch reduction across taxa to provide better understanding of the broad effects of bycatch reduction methods.
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Affiliation(s)
- Laura K. Jordan
- Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Corresponding author: Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA. Tel: +1 909 240 9703.
| | - John W. Mandelman
- John H. Prescott Marine Laboratory, New England Aquarium, Boston, MA 02110, USA
| | | | - Sonja V. Fordham
- Shark Advocates International, a project of The Ocean Foundation, Washington, DC 20036, USA
| | - John K. Carlson
- Southeast Fisheries Science Center, NOAA Fisheries Service, Panama City, FL 32408, USA
| | - Timothy B. Werner
- Consortium for Wildlife Bycatch Reduction, New England Aquarium, Boston, MA 02110, USA
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Amann B, Hirmer S, Hauck SM, Kremmer E, Ueffing M, Deeg CA. True blue: S-opsin is widely expressed in different animal species. J Anim Physiol Anim Nutr (Berl) 2012; 98:32-42. [PMID: 23173557 DOI: 10.1111/jpn.12016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Colour vision in animals is an interesting, fascinating subject. In this study, we examined a wide variety of species for expression of S-opsin (blue sensitive) and M-/L-opsin (green-red sensitive) in retinal cones using two novel monoclonal antibodies specific for peptides from human opsins. Mouse, rat and hare did not express one of the investigated epitopes, but we could clearly prove existence of cones through peanut agglutinin labelling. Retinas of guinea pig, dog, wolf, marten, cat, roe deer, pig and horse were positive for S-opsin, but not for M-/L-opsin. Nevertheless all these species are clearly at least dichromats, because we could detect further S-opsin negative cones by labelling with cone arrestin specific antibody. In contrast, pheasant and char had M-/L-opsin positive cones, but no S-opsin expressing cones. Sheep, cattle, monkey, men, pigeon, duck and chicken were positive for both opsins. Visual acuity analyzed through density of retinal ganglion cells revealed least visual discrimination by horses and highest resolution in pheasant and pigeon. Most mammals studied are dichromats with visual perception similar to red-green blind people.
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Affiliation(s)
- B Amann
- Institute of Animal Physiology, Department of Veterinary Sciences, LMU Munich, München, Germany Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany Institute of Molecular Immunology, Helmholtz Zentrum München, German Research Center for Environmental Health, München, Germany Centre of Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
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Theiss SM, Davies WIL, Collin SP, Hunt DM, Hart NS. Cone monochromacy and visual pigment spectral tuning in wobbegong sharks. Biol Lett 2012; 8:1019-22. [PMID: 22993239 DOI: 10.1098/rsbl.2012.0663] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Much is known regarding the evolution of colour vision in nearly every vertebrate class, with the notable exception of the elasmobranchs. While multiple spectrally distinct cone types are found in some rays, sharks appear to possess only a single class of cone and, therefore, may be colour blind. In this study, the visual opsin genes of two wobbegong species, Orectolobus maculatus and Orectolobus ornatus, were isolated to verify the molecular basis of their monochromacy. In both species, only two opsin genes are present, RH1 (rod) and LWS (cone), which provide further evidence to support the concept that sharks possess only a single cone type. Examination of the coding sequences revealed substitutions that account for interspecific variation in the photopigment absorbance spectra, which may reflect the difference in visual ecology between these species.
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Affiliation(s)
- Susan M Theiss
- School of Geography, Planning and Environmental Management, University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia.
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DAVIES WAYNEIL, COLLIN SHAUNP, HUNT DAVIDM. Molecular ecology and adaptation of visual photopigments in craniates. Mol Ecol 2012; 21:3121-58. [DOI: 10.1111/j.1365-294x.2012.05617.x] [Citation(s) in RCA: 156] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Harahush BK, Green K, Webb R, Hart NS, Collin SP. Optimal preservation of the shark retina for ultrastructural analysis: An assessment of chemical, microwave, and high-pressure freezing fixation techniques. Microsc Res Tech 2012; 75:1218-28. [DOI: 10.1002/jemt.22052] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 03/09/2012] [Indexed: 01/13/2023]
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Lisney TJ, Theiss SM, Collin SP, Hart NS. Vision in elasmobranchs and their relatives: 21st century advances. JOURNAL OF FISH BIOLOGY 2012; 80:2024-54. [PMID: 22497415 DOI: 10.1111/j.1095-8649.2012.03253.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This review identifies a number of exciting new developments in the understanding of vision in cartilaginous fishes that have been made since the turn of the century. These include the results of studies on various aspects of the visual system including eye size, visual fields, eye design and the optical system, retinal topography and spatial resolving power, visual pigments, spectral sensitivity and the potential for colour vision. A number of these studies have covered a broad range of species, thereby providing valuable information on how the visual systems of these fishes are adapted to different environmental conditions. For example, oceanic and deep-sea sharks have the largest eyes amongst elasmobranchs and presumably rely more heavily on vision than coastal and benthic species, while interspecific variation in the ratio of rod and cone photoreceptors, the topographic distribution of the photoreceptors and retinal ganglion cells in the retina and the spatial resolving power of the eye all appear to be closely related to differences in habitat and lifestyle. Multiple, spectrally distinct cone photoreceptor visual pigments have been found in some batoid species, raising the possibility that at least some elasmobranchs are capable of seeing colour, and there is some evidence that multiple cone visual pigments may also be present in holocephalans. In contrast, sharks appear to have only one cone visual pigment. There is evidence that ontogenetic changes in the visual system, such as changes in the spectral transmission properties of the lens, lens shape, focal ratio, visual pigments and spatial resolving power, allow elasmobranchs to adapt to environmental changes imposed by habitat shifts and niche expansion. There are, however, many aspects of vision in these fishes that are not well understood, particularly in the holocephalans. Therefore, this review also serves to highlight and stimulate new research in areas that still require significant attention.
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Affiliation(s)
- T J Lisney
- Department of Psychology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
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