Show simple item record Corfield, Jeremy R. Gsell, Anna C. Brunton, Dianne Heesy, Christopher P. Hall, Margaret I. Acosta, Monica L. Iwaniuk, Andrew N. 2016-11-10T21:37:57Z 2016-11-10T21:37:57Z 2011
dc.identifier.citation Corfield, J. R., Gsell, A. C., Brunton, D., Heesy, C. P., Hall, M. I., Acosta, M. L., & Iwaniuk, A. N. (2011). Anatomical specializations for nocturnality in a critically endangered parrot, the Kakapo (Strigops habroptilus). PLoS ONE, 6(8), e22945. doi:10.1371/journal.pone.0022945 en_US
dc.description Sherpa Romeo green journal: open access en_US
dc.description.abstract The shift from a diurnal to nocturnal lifestyle in vertebrates is generally associated with either enhanced visual sensitivity or a decreased reliance on vision. Within birds, most studies have focused on differences in the visual system across all birds with respect to nocturnality-diurnality. The critically endangered Kakapo (Strigops habroptilus), a parrot endemic to New Zealand, is an example of a species that has evolved a nocturnal lifestyle in an otherwise diurnal lineage, but nothing is known about its’ visual system. Here, we provide a detailed morphological analysis of the orbits, brain, eye, and retina of the Kakapo and comparisons with other birds. Morphometric analyses revealed that the Kakapo’s orbits are significantly more convergent than other parrots, suggesting an increased binocular overlap in the visual field. The Kakapo exhibits an eye shape that is consistent with other nocturnal birds, including owls and nightjars, but is also within the range of the diurnal parrots. With respect to the brain, the Kakapo has a significantly smaller optic nerve and tectofugal visual pathway. Specifically, the optic tectum, nucleus rotundus and entopallium were significantly reduced in relative size compared to other parrots. There was no apparent reduction to the thalamofugal visual pathway. Finally, the retinal morphology of the Kakapo is similar to that of both diurnal and nocturnal birds, suggesting a retina that is specialised for a crepuscular niche. Overall, this suggests that the Kakapo has enhanced light sensitivity, poor visual acuity and a larger binocular field than other parrots. We conclude that the Kakapo possesses a visual system unlike that of either strictly nocturnal or diurnal birds and therefore does not adhere to the traditional view of the evolution of nocturnality in birds. en_US
dc.language.iso en_CA en_US
dc.publisher Public Library of Science en_US
dc.subject Kakapo en_US
dc.subject Strigops habroptilus en_US
dc.subject Nocturnal en_US
dc.subject Diurnal en_US
dc.subject Visual system en_US
dc.subject Visual pathway en_US
dc.subject Morphological analysis en_US
dc.title Anatomical specializations for nocturnality in a critically endangered parrot, the Kakapo (Strigops habroptilus) en_US
dc.type Article en_US
dc.publisher.faculty Arts and Science en_US
dc.publisher.department Department of Neuroscience en_US
dc.description.peer-review Yes en_US
dc.publisher.institution University of Lethbridge en_US
dc.publisher.institution Massey University en_US
dc.publisher.institution Midwestern University en_US
dc.publisher.institution University of Auckland en_US

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