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Chong KL, Grahn A, Perl CD, Sumner-Rooney L. Allometry and ecology shape eye size evolution in spiders. Curr Biol 2024; 34:3178-3188.e5. [PMID: 38959880 DOI: 10.1016/j.cub.2024.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 05/11/2024] [Accepted: 06/07/2024] [Indexed: 07/05/2024]
Abstract
Eye size affects many aspects of visual function, but eyes are costly to grow and maintain. The allometry of eyes can provide insight into this trade-off, but this has mainly been explored in species that have two eyes of equal size. By contrast, animals possessing larger visual systems can exhibit variable eye sizes within individuals. Spiders have up to four pairs of eyes whose sizes vary dramatically, but their ontogenetic, static, and evolutionary allometry has not yet been studied in a comparative context. We report variable dynamics in eye size across 1,098 individuals in 39 species and 8 families, indicating selective pressures and constraints driving the evolution of different eye pairs and lineages. Supplementing our sampling with a recently published phylogenetically comprehensive dataset, we confirmed these findings across more than 400 species; found that ecological factors such as visual hunting, web building, and circadian activity correlate with eye diameter; and identified significant allometric shifts across spider phylogeny using an unbiased approach, many of which coincide with visual hunting strategies. The modular nature of the spider visual system provides additional degrees of freedom and is apparent in the strong correlations between maximum/minimum investment and interocular variance and three key ecological factors. Our analyses suggest an antagonistic relationship between the anterior and posterior eye pairs. These findings shed light on the relationship between spider visual systems and their diverse ecologies and how spiders exploit their modular visual systems to balance selective pressures and optical and energetic constraints.
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Affiliation(s)
- Kaylin L Chong
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA; Oxford University Museum of Natural History, University of Oxford, Oxford OX1 3PW, UK.
| | - Angelique Grahn
- Institut für Biologie, Humboldt Universität, Invalidenstrasse 42, 10115 Berlin, Germany
| | - Craig D Perl
- School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA
| | - Lauren Sumner-Rooney
- Oxford University Museum of Natural History, University of Oxford, Oxford OX1 3PW, UK.
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2
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Song Z, Griesser M, Schuppli C, van Schaik CP. Does the expensive brain hypothesis apply to amphibians and reptiles? BMC Ecol Evol 2023; 23:77. [PMID: 38114918 PMCID: PMC10729550 DOI: 10.1186/s12862-023-02188-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 12/09/2023] [Indexed: 12/21/2023] Open
Abstract
Vertebrate brains show extensive variation in relative size. The expensive brain hypothesis argues that one important source of this variation is linked to a species' ability to generate the energy required to sustain the brain, especially during periods of unavoidable food scarcity. Here we ask whether this hypothesis, tested so far in endothermic vertebrates, also applies to ectotherms, where ambient temperature is an additional major aspect of energy balance. Phylogenetic comparative analyses of reptiles and amphibians support the hypothesis. First, relative brain size increases with higher body temperature in those species active during the day that can gain free energy by basking. Second, relative brain size is smaller among nocturnal species, which generally face less favorable energy budgets, especially when maintaining high body temperature. However, we do not find an effect of seasonal variation in ambient temperature or food on brain size, unlike in endotherms. We conclude that the factors affecting energy balance in ectotherms and endotherms are overlapping but not identical. We therefore discuss the idea that when body temperatures are seasonally very low, cognitive benefits may be thwarted and selection on larger brain size may be rare. Indeed, mammalian hibernators may show similarities to ectotherms.
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Affiliation(s)
- Zitan Song
- Comparative Socioecology group, Department for the Ecology of Animal Societies, Max Planck Institute for Animal Behavior, 78467, Konstanz, Germany.
| | - Michael Griesser
- Department of Biology, University of Konstanz, 78467, Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78467, Konstanz, Germany
- Department of Collective Behavior, Max Planck Institute of Animal Behavior, 78467, Konstanz, Germany
| | - Caroline Schuppli
- Development and Evolution of Cognition Group, Max Planck Institute for Animal Behavior, 78467, Konstanz, Germany
| | - Carel P van Schaik
- Comparative Socioecology group, Department for the Ecology of Animal Societies, Max Planck Institute for Animal Behavior, 78467, Konstanz, Germany
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, 8057, Switzerland
- Center for the Interdisciplinary Study of language Evolution, University of Zurich, Zurich, 8057, Switzerland
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3
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Liu Y, Jiang Y, Xu J, Liao W. Evolution of Avian Eye Size Is Associated with Habitat Openness, Food Type and Brain Size. Animals (Basel) 2023; 13:ani13101675. [PMID: 37238105 DOI: 10.3390/ani13101675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/14/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
The eye is the primary sensory organ that obtains information from the ecological environments and specifically bridges the brain with the extra environment. However, the coevolutionary relationships between eye size and ecological factors, behaviours and brain size in birds remain poorly understood. Here, we investigate whether eye size evolution is associated with ecological factors (e.g., habitat openness, food type and foraging habitat), behaviours (e.g., migration and activity pattern) and brain size among 1274 avian species using phylogenetically controlled comparative analyses. Our results indicate that avian eye size is significantly associated with habitat openness, food type and brain size. Species living in dense habitats and consuming animals exhibit larger eye sizes compared to species living in open habitats and consuming plants, respectively. Large-brained birds tend to possess larger eyes. However, migration, foraging habitat and activity pattern were not found to be significantly associated with eye size in birds, except for nocturnal birds having longer axial lengths than diurnal ones. Collectively, our results suggest that avian eye size is primarily influenced by light availability, food need and cognitive ability.
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Affiliation(s)
- Yating Liu
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China
| | - Ying Jiang
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China
| | - Jiliang Xu
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China
| | - Wenbo Liao
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, China
- Key Laboratory of Artificial Propagation and Utilization in Anurans of Nanchong City, China West Normal University, Nanchong 637009, China
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4
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Geographical Variation in Body Size and the Bergmann's Rule in Andrew's Toad ( Bufo andrewsi). BIOLOGY 2022; 11:biology11121766. [PMID: 36552274 PMCID: PMC9775554 DOI: 10.3390/biology11121766] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022]
Abstract
Environmental variation likely modifies the life-history traits of vertebrates. As ectothermic vertebrates, it is possible that the body size of amphibians is impacted by environmental conditions. Here, we firstly quantified age and body size variation in the Andrew's toad (Bufo andrewsi) across the Hengduan Mountains. Then, we examined the environmental correlates of this variation based on the literature and our unpublished data on the age and body size of the Andrew's toad from 31 populations distributed in southwestern China. Although our analysis revealed significant variations in age and body size across B. andrewsi populations, neither latitude nor altitude correlated with this variability in age and body size. We found that age at sexual maturity, mean age, and longevity increased with decreasing annual mean temperature, whereas age at sexual maturity increased with decreasing temperature seasonality, implying that temperature was a crucial habitat characteristic that modulated age structure traits. Moreover, we revealed positive associations between age structure and UV-B seasonality, and negative relationships between both mean age and longevity and precipitation seasonality. We also found that body size increased with increasing precipitation in the driest month and UV-B seasonality. However, body size did not covary with temperature, signifying no support for Bergmann's rule. These findings help us to understand amphibians' abilities to adapt to environmental variation, which is particularly important in order to provide a theorical basis for their conservation.
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5
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Jiang Y, Chen C, Liao W. Anuran interorbital distance variation: the role of ecological and behavioral factors. Integr Zool 2022; 17:777-786. [PMID: 35512218 DOI: 10.1111/1749-4877.12653] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Eye position varies significantly among taxonomic levels, and this variation is often shaped by ecological and behavioral factors. Eye position is often positively associated with interorbital distance where species with broad visual fields possess a large distance between the left and right eye. Selective pressures underlying the evolution of the eye position are especially studied in birds and mammals. However, selective pressures underling the evolution of anuran eye position which can be indicated by interorbital distance keep unknown. Here, we investigated the effects of ecological (e.g., habitat type, light availability) and behavioral factors (e.g., activity pattern, foraging mobility, and defensive strategy) on variations in interorbital distance among 260 anuran species in China. Our results showed that variations of the interorbital distance can be significantly predicted by the activity pattern. Nocturnal species had larger interorbital distance than both nocturnal and diurnal species. We also found that foraging mobility and defensive strategy affected markedly variation of interorbital distance. Species having slower foraging mobility and possessing poison glands had larger interorbital distance than species having faster foraging mobility and possessing non-position glands. Light availability tended to be associated with variation of interorbital distance, indicating that species living weak light tending to possess larger interorbital distance. However, variations of the interorbital space were not associated with habitat type in anurans. Our findings suggest that anuran behaviors play key roles in shaping visual fields and eye position, and thus affecting the evolution of interorbital distance. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Ying Jiang
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, China.,Key Laboratory of Artificial Propagation and Utilization in Anurans of Nanchong City, China West Normal University, Nanchong, China.,Institute of Eco-adaptation in Amphibians and Reptiles, China West Normal University, Nanchong, China
| | - Chuan Chen
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, China.,Key Laboratory of Artificial Propagation and Utilization in Anurans of Nanchong City, China West Normal University, Nanchong, China.,Institute of Eco-adaptation in Amphibians and Reptiles, China West Normal University, Nanchong, China
| | - Wenbo Liao
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, China.,Key Laboratory of Artificial Propagation and Utilization in Anurans of Nanchong City, China West Normal University, Nanchong, China.,Institute of Eco-adaptation in Amphibians and Reptiles, China West Normal University, Nanchong, China
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6
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Schott RK, Perez L, Kwiatkowski MA, Imhoff V, Gumm JM. Evolutionary analyses of visual opsin genes in frogs and toads: Diversity, duplication, and positive selection. Ecol Evol 2022; 12:e8595. [PMID: 35154658 PMCID: PMC8820127 DOI: 10.1002/ece3.8595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 01/07/2022] [Accepted: 01/08/2022] [Indexed: 01/12/2023] Open
Abstract
Among major vertebrate groups, anurans (frogs and toads) are understudied with regard to their visual systems, and little is known about variation among species that differ in ecology. We sampled North American anurans representing diverse evolutionary and life histories that likely possess visual systems adapted to meet different ecological needs. Using standard molecular techniques, visual opsin genes, which encode the protein component of visual pigments, were obtained from anuran retinas. Additionally, we extracted the visual opsins from publicly available genome and transcriptome assemblies, further increasing the phylogenetic and ecological diversity of our dataset to 33 species in total. We found that anurans consistently express four visual opsin genes (RH1, LWS, SWS1, and SWS2, but not RH2) even though reported photoreceptor complements vary widely among species. The proteins encoded by these genes showed considerable sequence variation among species, including at sites known to shift the spectral sensitivity of visual pigments in other vertebrates and had conserved substitutions that may be related to dim-light adaptation. Using molecular evolutionary analyses of selection (dN/dS) we found significant evidence for positive selection at a subset of sites in the dim-light rod opsin gene RH1 and the long wavelength sensitive cone opsin LWS. The function of sites inferred to be under positive selection are largely unknown, but a few are likely to affect spectral sensitivity and other visual pigment functions based on proximity to previously identified sites in other vertebrates. We also found the first evidence of visual opsin duplication in an amphibian with the duplication of the LWS gene in the African bullfrog, which had distinct LWS copies on the sex chromosomes suggesting the possibility of sex-specific visual adaptation. Taken together, our results indicate that ecological factors, such as habitat and life history, as well as behavior, may be driving changes to anuran visual systems.
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Affiliation(s)
- Ryan K. Schott
- Department of BiologyYork UniversityTorontoOntarioCanada
- Department of Vertebrate ZoologyNational Museum of Natural HistorySmithsonian InstitutionWashingtonDistrict of ColumbiaUSA
| | - Leah Perez
- Department of BiologyStephen F. Austin State UniversityNacogdochesTexasUSA
| | | | - Vance Imhoff
- Southern Nevada Fish and Wildlife OfficeUS Fish and Wildlife ServiceLas VegasNevadaUSA
| | - Jennifer M. Gumm
- Department of BiologyStephen F. Austin State UniversityNacogdochesTexasUSA
- Ash Meadows Fish Conservation FacilityUS Fish and Wildlife ServiceAmargosa ValleyNevadaUSA
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7
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Chen C, Jiang Y, Jin L, Liao WB. No Evidence for Effects of Ecological and Behavioral Factors on Eye Size Evolution in Anurans. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.755818] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Eye size varies markedly among taxonomic levels, and this variation is often related to the patterns shaped by phylogeny and ecological and behavioral factors. The selective pressures underlying eye size evolution are especially studied in fishes, anurans, birds, and mammals. However, selective pressures underlying the eye size evolution in anurans have inconsistent scaling rules. Here, we investigated the links between eye size and both ecological (e.g., light availability and habitat type) and behavioral factors (e.g., activity time, foraging mobility, defensive strategy, and mating system) among 252 species of anurans by using phylogenetically controlled generalized least-squared (PGLS) regression. Results show that anuran eye size scales hypo-allometrically with body size. However, eye size was not significantly influenced by ecological and behavioral factors, including habitat type, activity time, light availability, foraging mobility, defensive strategy, and mating system. Therefore, neither ecology nor behavior plays a key role in promoting eye size evolution in frogs.
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8
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Ausprey IJ, Newell FL, Robinson SK. Adaptations to light predict the foraging niche and disassembly of avian communities in tropical countrysides. Ecology 2020; 102:e03213. [PMID: 33002207 DOI: 10.1002/ecy.3213] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 06/21/2020] [Accepted: 08/06/2020] [Indexed: 12/22/2022]
Abstract
The role of light in partitioning ecological niche space remains a frontier in understanding the assembly of terrestrial vertebrate communities and their response to global change. Leveraging recent advances in biologging technology and intensive field surveys of cloud forest bird communities across an agricultural land use gradient in the Peruvian Andes, we demonstrate that eye size predicts (1) the ambient light microenvironment used by free-ranging birds, (2) their foraging niche, and (3) species-specific sensitivity to agricultural land use change. For 15 species carrying light sensors (N = 71 individuals), light intensity levels were best explained by eye size and foraging behavior, with larger-eyed species using darker microenvironments. Across the cloud forest bird community (N = 240 species), hyperopic ("far-sighted") foragers, (e.g., flycatchers), had larger eyes compared to myopic ("near-sighted") species (e.g., gleaners and frugivores); eye size was also larger for myopic insectivores that foraged in the forest understory. Eye size strongly predicted sensitivity to brightly lit habitats across an agricultural land use gradient. Species that increased in abundance in mixed intensity agriculture, including fencerows, silvopasture, and pasture, had smaller eyes, suggesting that light acts as an environmental filter when communities disassemble in a human-disturbed landscape. We suggest that eye size represents a novel functional trait contributing to terrestrial vertebrate community assembly and sensitivity to habitat disturbance.
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Affiliation(s)
- Ian J Ausprey
- Florida Museum of Natural History and Department of Biology, University of Florida, Gainesville, Florida, 32611, USA
| | - Felicity L Newell
- Florida Museum of Natural History and Department of Biology, University of Florida, Gainesville, Florida, 32611, USA
| | - Scott K Robinson
- Florida Museum of Natural History and Department of Biology, University of Florida, Gainesville, Florida, 32611, USA
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9
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Sultan AE, Ghoneim AM, El-Gammal HL, El-Bakary NER. Vision adaptation in the laughing dove (Streptopelia senegalensis, Linnaeus, 1766) inferred from structural, ultrastructural, and genetic characterization. J Comp Neurol 2020; 529:1830-1848. [PMID: 33094834 DOI: 10.1002/cne.25059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 10/12/2020] [Accepted: 10/19/2020] [Indexed: 11/06/2022]
Abstract
Neuroanatomy of the retina reflects adaptation and acclimation for dark and light conditions. Retinal cells and genes must be functionally adjusted to various environmental luminosities. Opsins are brilliant molecules to assess the adaptations at the genetic and phenotypic levels. Photic adaptations may reveal new mechanisms that enhance vision abilities. Through the investigation of histological, ultrastructural constituents of the whole retinal layers, and the sequencing of shortwave length sensitive opsin 1 (SWS1) of the laughing dove (Streptopelia senegalensis), the current study confirms the plasticity of the retina in response to the natural photic conditions. Retinal pigmented epithelium has plentiful melanosomes, signifying a highly adapted eye for maximum light perception and protection. Variously colored oil droplets signify high color vision ability. Stratified outer nuclear layer with many Müller cells suggests high sensitivity to dim conditions and high retinal regeneration. The penetration of outer limiting membrane by photoreceptor nuclei and Müller cell microvilli could minimize the light reflection. Oligodendrocytes establish thick myelination demanded for a keen visual acuity. A functional violet sensitive SWS1 with crucial Ser90 is presumed. Molecular phylogeny showed a secondary loss as color vision was shifted back from ultraviolet (UV) sensitivity to the ancestral avian violet sensitivity, thus improving visual resolution. However, SWS1 has some UV sensitive residues. These findings implicate not only spectral adaptations with high color vision ability and acuity but also photoinduced structural reorganizations. Further studies are needed to assess the secrets between photons and the structural genes.
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Affiliation(s)
- Aya E Sultan
- Zoology Department, Faculty of Science, Damietta University, Damietta, Egypt
| | - Ahmed M Ghoneim
- Zoology Department, Faculty of Science, Damietta University, Damietta, Egypt
| | - Hekmat L El-Gammal
- Zoology Department, Faculty of Science, Damietta University, Damietta, Egypt
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Thomas KN, Gower DJ, Bell RC, Fujita MK, Schott RK, Streicher JW. Eye size and investment in frogs and toads correlate with adult habitat, activity pattern and breeding ecology. Proc Biol Sci 2020; 287:20201393. [PMID: 32962540 PMCID: PMC7542830 DOI: 10.1098/rspb.2020.1393] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Frogs and toads (Amphibia: Anura) display diverse ecologies and behaviours, which are often correlated with visual capacity in other vertebrates. Additionally, anurans exhibit a broad range of relative eye sizes, which have not previously been linked to ecological factors in this group. We measured relative investment in eye size and corneal size for 220 species of anurans representing all 55 currently recognized families and tested whether they were correlated with six natural history traits hypothesized to be associated with the evolution of eye size. Anuran eye size was significantly correlated with habitat, with notable decreases in eye investment among fossorial, subfossorial and aquatic species. Relative eye size was also associated with mating habitat and activity pattern. Compared to other vertebrates, anurans have relatively large eyes for their body size, indicating that vision is probably of high importance. Our study reveals the role that ecology and behaviour may have played in the evolution of anuran visual systems and highlights the usefulness of museum specimens, and importance of broad taxonomic sampling, for interpreting macroecological patterns.
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Affiliation(s)
- Kate N Thomas
- Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK
| | - David J Gower
- Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK
| | - Rayna C Bell
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560-0162, USA.,Department of Herpetology, California Academy of Sciences, San Francisco, CA 94118, USA
| | - Matthew K Fujita
- Department of Biology, Amphibian and Reptile Diversity Research Center, The University of Texas at Arlington, Arlington, TX 76019, USA
| | - Ryan K Schott
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560-0162, USA
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Hadden PW, Pas AE, Cassidy SB, Ober WC. The eye of the takahe, Porphyrio hochstetteri. NEW ZEALAND JOURNAL OF ZOOLOGY 2020. [DOI: 10.1080/03014223.2020.1792945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Peter W. Hadden
- Department of Ophthalmology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | | | | | - William C. Ober
- Cornell University – Shoals Marine Laboratory, Ithaca, NY, USA
- University of New Hampshire – Shoals Marine Laboratory, Durham, NH, USA
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