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Button DJ, Zanno LE. Neuroanatomy of the late Cretaceous Thescelosaurus neglectus (Neornithischia: Thescelosauridae) reveals novel ecological specialisations within Dinosauria. Sci Rep 2023; 13:19224. [PMID: 37932280 PMCID: PMC10628235 DOI: 10.1038/s41598-023-45658-3] [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: 06/06/2023] [Accepted: 10/22/2023] [Indexed: 11/08/2023] Open
Abstract
Ornithischian dinosaurs exhibited a diversity of ecologies, locomotory modes, and social structures, making them an ideal clade in which to study the evolution of neuroanatomy and behaviour. Here, we present a 3D digital reconstruction of the endocranial spaces of the latest Cretaceous neornithischian Thescelosaurus neglectus, in order to interpret the neuroanatomy and paleobiology of one of the last surviving non-avian dinosaurs. Results demonstrate that the brain of Thescelosaurus was relatively small compared to most other neornithischians, instead suggesting cognitive capabilities within the range of extant reptiles. Other traits include a narrow hearing range, with limited ability to distinguish high frequencies, paired with unusually well-developed olfactory lobes and anterior semicircular canals, indicating acute olfaction and vestibular sensitivity. This character combination, in conjunction with features of the postcranial anatomy, is consistent with specializations for burrowing behaviours in the clade, as evidenced by trace and skeletal fossil evidence in earlier-diverging thescelosaurids, although whether they reflect ecological adaptations or phylogenetic inheritance in T. neglectus itself is unclear. Nonetheless, our results provide the first evidence of neurological specializations to burrowing identified within Ornithischia, and non-avian dinosaurs more generally, expanding the range of ecological adaptations recognized within this major clade.
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Affiliation(s)
- David J Button
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Bristol, BS8 1TQ, UK.
| | - Lindsay E Zanno
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC, USA
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
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2
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Cantlay JC, Martin GR, McClelland SC, Potier S, O'Brien MF, Fernández-Juricic E, Bond AL, Portugal SJ. Binocular vision and foraging in ducks, geese and swans (Anatidae). Proc Biol Sci 2023; 290:20231213. [PMID: 37670586 PMCID: PMC10510447 DOI: 10.1098/rspb.2023.1213] [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: 05/31/2023] [Accepted: 08/02/2023] [Indexed: 09/07/2023] Open
Abstract
Wide variation in visual field configuration across avian species is hypothesized to be driven primarily by foraging ecology and predator detection. While some studies of selected taxa have identified relationships between foraging ecology and binocular field characteristics in particular species, few have accounted for the relevance of shared ancestry. We conducted a large-scale, comparative analysis across 39 Anatidae species to investigate the relationship between the foraging ecology traits of diet or behaviour and binocular field parameters, while controlling for phylogeny. We used phylogenetic models to examine correlations between traits and binocular field characteristics, using unidimensional and morphometric approaches. We found that foraging behaviour influenced three parameters of binocular field size: maximum binocular field width, vertical binocular field extent, and angular separation between the eye-bill projection and the direction of maximum binocular field width. Foraging behaviour and body mass each influenced two descriptors of binocular field shape. Phylogenetic relatedness had minimal influence on binocular field size and shape, apart from vertical binocular field extent. Binocular field differences are associated with specific foraging behaviours, as related to the perceptual challenges of obtaining different food items from aquatic and terrestrial environments.
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Affiliation(s)
- Jennifer C. Cantlay
- Department of Biological Sciences, School of Life and Environmental Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
| | - Graham R. Martin
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Stephanie C. McClelland
- Department of Biological Sciences, School of Life and Environmental Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
| | - Simon Potier
- Department of Biology, Faculty of Science, Lund University, Sölvegatan 35, 223 62 Lund, Sweden
| | | | | | - Alexander L. Bond
- Bird Group, Department of Life Sciences, The Natural History Museum, Akeman Street, Tring, Hertfordshire HP23 6AP, UK
| | - Steven J. Portugal
- Department of Biological Sciences, School of Life and Environmental Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
- Bird Group, Department of Life Sciences, The Natural History Museum, Akeman Street, Tring, Hertfordshire HP23 6AP, UK
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3
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The endocast of the insular and extinct Sylviornis neocaledoniae (Aves, Galliformes), reveals insights into its sensory specializations and its twilight ecology. Sci Rep 2022; 12:21185. [PMID: 36477415 PMCID: PMC9729198 DOI: 10.1038/s41598-022-14829-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 06/13/2022] [Indexed: 12/12/2022] Open
Abstract
Sylviornis neocaledoniae (Galliformes, Sylviornithidae), a recently extinct bird of New-Caledonia (Galliformes, Sylviornithidae) is the largest galliform that ever lived and one of the most enigmatic birds in the world. Herein, for the first time, we analyze its neuroanatomy that sheds light on its lifestyle, its brain shape and patterns being correlated to neurological functions. Using morphometric methods, we quantified the endocranial morphology of S. neocaledoniae and compared it with extinct and extant birds in order to obtain ecological and behavioral information about fossil birds. Sylviornis neocaledoniae exhibited reduced optic lobes, a condition also observed in nocturnal taxa endemic to predator-depauperate islands, such as Elephant birds. Functional interpretations suggest that S. neocaledoniae possessed a well-developed somatosensorial system and a good sense of smell in addition to its specialized visual ability for low light conditions, presumably for locating its food. We interpret these results as evidence for a crepuscular lifestyle in S. neocaledoniae.
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Núñez‐León D, Nagashima H, Sánchez‐Villagra MR. Chondrocranial variation in chicken domestication. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B: MOLECULAR AND DEVELOPMENTAL EVOLUTION 2022; 338:505-515. [DOI: 10.1002/jez.b.23177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 08/09/2022] [Accepted: 09/01/2022] [Indexed: 11/18/2022]
Affiliation(s)
- Daniel Núñez‐León
- Paleontological Institute and Museum University of Zurich Zürich Switzerland
| | - Hiroshi Nagashima
- Division of Anatomy Niigata University Graduate School of Medical and Dental Sciences Niigata Japan
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5
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Undin M, Castro I. Predicting breeding systems to guide conservation strategies: A kiwi example. Ethology 2022. [DOI: 10.1111/eth.13286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Malin Undin
- Department of Natural Sciences Mid Sweden University Sundsvall Sweden
- Wildlife and Ecology Group, School of Agriculture and Environment Massey University Palmerston North New Zealand
| | - Isabel Castro
- Wildlife and Ecology Group, School of Agriculture and Environment Massey University Palmerston North New Zealand
- Wildbase Research Massey University Palmerston North New Zealand
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6
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Wang L, Sun L, Wan QH, Fang SG. Comparative Genomics Provides Insights into Adaptive Evolution in Tactile-Foraging Birds. Genes (Basel) 2022; 13:genes13040678. [PMID: 35456484 PMCID: PMC9028243 DOI: 10.3390/genes13040678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 04/07/2022] [Accepted: 04/11/2022] [Indexed: 11/28/2022] Open
Abstract
Tactile-foraging birds have evolved an enlarged principal sensory nucleus (PrV) but smaller brain regions related to the visual system, which reflects the difference in sensory dependence. The “trade-off” may exist between different senses in tactile foragers, as well as between corresponding sensory-processing areas in the brain. We explored the mechanism underlying the adaptive evolution of sensory systems in three tactile foragers (kiwi, mallard, and crested ibis). The results showed that olfaction-related genes in kiwi and mallard and hearing-related genes in crested ibis were expanded, indicating they may also have sensitive olfaction or hearing, respectively. However, some genes required for visual development were positively selected or had convergent amino acid substitutions in all three tactile branches, and it seems to show the possibility of visual degradation. In addition, we may provide a new visual-degradation candidate gene PDLIM1 who suffered dense convergent amino acid substitutions within the ZM domain. At last, two genes responsible for regulating the proliferation and differentiation of neuronal progenitor cells may play roles in determining the relative sizes of sensory areas in brain. This exploration offers insight into the relationship between specialized tactile-forging behavior and the evolution of sensory abilities and brain structures.
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Delaunay MG, Charter M, Grant RA. Anatomy of bristles on the nares and rictus of western barn owls (Tyto alba). J Anat 2022; 241:527-534. [PMID: 35315065 PMCID: PMC9296031 DOI: 10.1111/joa.13655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/01/2022] [Accepted: 03/03/2022] [Indexed: 12/02/2022] Open
Abstract
Many nocturnal avian species, such as Strigiformes, Caprimulgiformes and Apterygiformes, have sensitive vibrotactile bristles on their upper bill, especially on their rictus. The anatomy of these bristles can vary, especially in terms of sensitivity (Herbst corpuscle number), bristle length and bristle number. This variation is thought to be associated with foraging – such that diurnal, open foragers have smaller and less‐sensitive bristles. Here, we describe bristle morphology and follicle anatomy in the western barn owl (Tyto alba) for the first time, using both live and roadkill wild owls. We show that T. alba have both narial and rictal bristles that are likely to be vibrotactile, since they have Herbst corpuscles around their follicles. We observed more numerous (~8) and longer bristles (~16 mm) on the nares of T. alba, than on the rictal region (~4 and ~13 mm respectively). However, the narial bristle follicles contained fewer Herbst corpuscles in their surroundings (~5) than the rictal bristles (~7); indicating that bristle length is not indicative of sensitivity. As well as bristle length and number varying between different facial regions, they also varied between individuals, although the cause of this variation remains unclear. Despite this variation, the gross anatomy of facial bristle follicles appears to be conserved between nocturnal Strigiformes, Caprimulgiformes and Apterygiformes. Understanding more about how T. alba use their bristles would, therefore, give us greater insights into the function of avian bristles in general.
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Affiliation(s)
- Mariane G Delaunay
- Department of Natural Science, Manchester Metropolitan University, Manchester, UK
| | - Motti Charter
- The Shamir Research Institute and the Department of Geography and Environmental Studies, University of Haifa, Haifa, Israel
| | - Robyn A Grant
- Department of Natural Science, Manchester Metropolitan University, Manchester, UK
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Undin M, Lockhart PJ, Hills SFK, Armstrong DP, Castro I. Mixed Mating in a Multi-Origin Population Suggests High Potential for Genetic Rescue in North Island Brown Kiwi, Apteryx mantelli. FRONTIERS IN CONSERVATION SCIENCE 2021. [DOI: 10.3389/fcosc.2021.702128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Reinforcement translocations are increasingly utilised in conservation with the goal of achieving genetic rescue. However, concerns regarding undesirable results, such as genetic homogenisation or replacement, are widespread. One factor influencing translocation outcomes is the rate at which the resident and the introduced individuals interbreed. Consequently, post-release mate choice is a key behaviour to consider in conservation planning. Here we studied mating, and its consequences for genomic admixture, in the North Island brown kiwi Apteryx mantelli population on Ponui Island which was founded by two translocation events over 50 years ago. The two source populations used are now recognised as belonging to two separate management units between which birds differ in size and are genetically differentiated. We examined the correlation between male and female morphometrics for 17 known pairs and quantified the relatedness of 20 pairs from this admixed population. In addition, we compared the genetic similarity and makeup of 106 Ponui Island birds, including 23 known pairs, to birds representing the source populations for the original translocations. We found no evidence for size-assortative mating. On the contrary, genomic SNP data suggested that kiwi of one feather did not flock together, meaning that mate choice resulted in pairing between individuals that were less related than expected by random chance. Furthermore, the birds in the current Ponui Island population were found to fall along a gradient of genomic composition consistent with non-clustered representation of the two parental genomes. These findings indicate potential for successful genetic rescue in future Apteryx reinforcement translocations, a potential that is currently under utilised due to restrictive translocation policies. In light of our findings, we suggest that reconsideration of these policies could render great benefits for the future diversity of this iconic genus in New Zealand.
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Hüppi E, Werneburg I, Sánchez-Villagra MR. Evolution and development of the bird chondrocranium. Front Zool 2021; 18:21. [PMID: 33926502 PMCID: PMC8082637 DOI: 10.1186/s12983-021-00406-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 04/08/2021] [Indexed: 01/29/2023] Open
Abstract
Background Birds exhibit an enormous diversity in adult skull shape (disparity), while their embryonic chondrocrania are considered to be conserved across species. However, there may be chondrocranial features that are diagnostic for bird clades or for Aves as a whole. We synthesized and analyzed information on the sequence of chondrification of 23 elements in ten bird species and five outgroups. Moreover, we critically considered the developmental morphology of the chondrocrania of 21 bird species and examined whether the diversity in adult skull shape is reflected in the development of the embryonic skull, and whether there are group-specific developmental patterns. Results We found that chondrocranial morphology is largely uniform in its major features, with some variation in the presence or absence of fenestrae and other parts. In kiwis (Apteryx), the unique morphology of the bony skull in the orbito-nasal region is reflected in its chondrocranial anatomy. Finally, differences in morphology and chondrification sequence may distinguish between different Palaeognathae and Neognathae and between the Galloanserae and Neoaves. The sequence of chondrification is largely conserved in birds, but with some variation in most regions. The peri- and prechordal areas in the base of the chondrocranium are largely conserved. In contrast to the outgroups, chondrification in birds starts in the acrochordal cartilage and the basicranial fenestra is formed secondarily. Further differences concern the orbital region, including early chondrification of the pila antotica and the late formation of the planum supraseptale. Conclusion Synthesizing information on chondrocranial development confronts terminological issues and a lack of comparable methods used (e.g., different staining; whole-mounts versus histology). These issues were taken into consideration when assessing differences across species. The summary of works on avian chondrocranial development, covered more than a century, and a comparison of the chondrification sequence among birds could be conducted. Future studies could test the hypothesis that chondrocranial disparity in Aves, in terms of the shape and proportion of individual elements, could be as large as adult skull disparity, despite conserved developmental patterns and the richness of forms in other (dermal) portions of the skull. Supplementary Information The online version contains supplementary material available at 10.1186/s12983-021-00406-z.
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Affiliation(s)
- Evelyn Hüppi
- Universität Zürich, Paläontologisches Institut und Museum, Karl-Schmid-Straße 4, 8006, Zürich, Switzerland.
| | - Ingmar Werneburg
- Senckenberg Center for Human Evolution and Palaeoenvironment (HEP) an der Eberhard Karls Universität, Sigwartstraße 10, 72076, Tübingen, Germany.,Fachbereich Geowissenschaften der Eberhard-Karls-Universität Tübingen, Hölderlinstraße 12, 72074, Tübingen, Germany
| | - Marcelo R Sánchez-Villagra
- Universität Zürich, Paläontologisches Institut und Museum, Karl-Schmid-Straße 4, 8006, Zürich, Switzerland
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10
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Hogan AVC, Watanabe A, Balanoff AM, Bever GS. Comparative growth in the olfactory system of the developing chick with considerations for evolutionary studies. J Anat 2020; 237:225-240. [PMID: 32314400 PMCID: PMC7369194 DOI: 10.1111/joa.13197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 02/17/2020] [Accepted: 03/10/2020] [Indexed: 12/26/2022] Open
Abstract
Despite the long-held assumption that olfaction plays a relatively minor role in the behavioral ecology of birds, crown-group avians exhibit marked phylogenetic variation in the size and form of the olfactory apparatus. As part of a larger effort to better understand the role of olfaction and olfactory tissues in the evolution and development of the avian skull, we present the first quantitative analysis of ontogenetic scaling between olfactory features [olfactory bulbs (OBs) and olfactory turbinates] and neighboring structures (cerebrum, total brain, respiratory turbinates) based on the model organism Gallus gallus. The OB develops under the predictions of a concerted evolutionary model with rapid early growth that is quickly overcome by the longer, sustained growth of the larger cerebrum. A similar pattern is found in the nasal cavity where the morphologically simple (non-scrolled) olfactory turbinates appear and mature early, with extended growth characterizing the larger and scrolled respiratory turbinates. Pairwise regressions largely recover allometric relationships among the examined structures, with a notable exception being the isometric trajectory of the OB and olfactory turbinate. Their parallel growth suggests a unique regulatory pathway that is likely driven by the morphogenesis of the olfactory nerve, which serves as a structural bridge between the two features. Still, isometry was not necessarily expected given that the olfactory epithelium covers more than just the turbinate. These data illuminate a number of evolutionary hypotheses that, moving forward, should inform tradeoffs and constraints between the olfactory and neighboring systems in the avian head.
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Affiliation(s)
- Aneila V. C. Hogan
- Center for Functional Anatomy and EvolutionJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Akinobu Watanabe
- Department of AnatomyNew York Institute of Technology College of Osteopathic MedicineNew YorkNYUSA
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNYUSA
- Life Sciences DepartmentVertebrates DivisionNatural History MuseumLondonUK
| | - Amy M. Balanoff
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNYUSA
- Department of Psychological and Brain SciencesJohns Hopkins UniversityBaltimoreMDUSA
| | - Gabriel S. Bever
- Center for Functional Anatomy and EvolutionJohns Hopkins University School of MedicineBaltimoreMDUSA
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNYUSA
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11
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Iwaniuk AN, Keirnan AR, Janetzki H, Mardon K, Murphy S, Leseberg NP, Weisbecker V. The endocast of the Night Parrot (Pezoporus occidentalis) reveals insights into its sensory ecology and the evolution of nocturnality in birds. Sci Rep 2020; 10:9258. [PMID: 32518353 PMCID: PMC7283296 DOI: 10.1038/s41598-020-65156-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 04/24/2020] [Indexed: 11/13/2022] Open
Abstract
The Night Parrot (Pezoporus occidentalis) is a rare, nocturnal parrot species that has largely escaped scientific investigation due to its behaviour and habitat preferences. Recent field studies have revealed some insights into Night Parrot behaviour, but nothing is known of its sensory abilities. Here, we used μCT scans of an intact Night Parrot specimen to determine if its visual system shares similarities with other nocturnal species. The endocast of the Night Parrot revealed relatively small optic lobes and optic foramina, especially compared with closely related grass parakeets, but no apparent differences in orbit dimensions. Our data suggests that the Night Parrot likely has lower visual acuity than most other parrots, including its congener, the Eastern Ground Parrot (P. wallicus). We propose that the visual system of the Night Parrot might represent a compromise between the need to see under low light conditions and the visual acuity required to detect predators, forage, and fly. Based on the endocast and optic foramen measurements, the Night Parrot fits into a common pattern of decreased retinal input to the optic lobes in birds that should be explored more thoroughly in extant and extinct species.
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Affiliation(s)
- Andrew N Iwaniuk
- Department of Neuroscience, University of Lethbridge, Lethbridge, AB, Canada.
| | - Aubrey R Keirnan
- School of Biological Sciences, University of Queensland, St. Lucia, QLD, Australia
| | | | - Karine Mardon
- Centre for Advanced Imaging, University of Queensland, St. Lucia, QLD, Australia
| | - Stephen Murphy
- School of Earth and Environmental Sciences, University of Queensland, St. Lucia, QLD, Australia
| | - Nicholas P Leseberg
- School of Earth and Environmental Sciences, University of Queensland, St. Lucia, QLD, Australia
| | - Vera Weisbecker
- School of Biological Sciences, University of Queensland, St. Lucia, QLD, Australia. .,College of Science and Engineering, Flinders University, GPO 2100, Adelaide, SA, Australia.
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Knoll F, Kawabe S. Avian palaeoneurology: Reflections on the eve of its 200th anniversary. J Anat 2020; 236:965-979. [PMID: 31999834 PMCID: PMC7219626 DOI: 10.1111/joa.13160] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 12/28/2019] [Accepted: 01/07/2020] [Indexed: 12/13/2022] Open
Abstract
In birds, the brain (especially the telencephalon) is remarkably developed, both in relative volume and complexity. Unlike in most early-branching sauropsids, the adults of birds and other archosaurs have a well-ossified neurocranium. In contrast to the situation in most of their reptilian relatives but similar to what can be seen in mammals, the brains of birds fit closely to the endocranial cavity so that their major external features are reflected in the endocasts. This makes birds a highly suitable group for palaeoneurological investigations. The first observation about the brain in a long-extinct bird was made in the first quarter of the 19th century. However, it was not until the 2000s and the application of modern imaging technologies that avian palaeoneurology really took off. Understanding how the mode of life is reflected in the external morphology of the brains of birds is but one of several future directions in which avian palaeoneurological research may extend. Although the number of fossil specimens suitable for palaeoneurological explorations is considerably smaller in birds than in mammals and will very likely remain so, the coming years will certainly witness a momentous strengthening of this rapidly growing field of research at the overlap between ornithology, palaeontology, evolutionary biology and neurosciences.
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Affiliation(s)
- Fabien Knoll
- ARAID‐Fundación Conjunto Paleontológico de Teruel‐DinópolisTeruelSpain
- Departamento de PaleobiologíaMuseo Nacional de Ciencias Naturales‐CSICMadridSpain
| | - Soichiro Kawabe
- Institute of Dinosaur ResearchFukui Prefectural UniversityFukuiJapan
- Fukui Prefectural Dinosaur MuseumFukuiJapan
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13
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Delaunay MG, Larsen C, Lloyd H, Sullivan M, Grant RA. Anatomy of avian rictal bristles in Caprimulgiformes reveals reduced tactile function in open-habitat, partially diurnal foraging species. J Anat 2020; 237:355-366. [PMID: 32202663 PMCID: PMC7369198 DOI: 10.1111/joa.13188] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 03/03/2020] [Indexed: 12/30/2022] Open
Abstract
Avian rictal bristles are present in many species of birds, especially in nocturnal species. Rictal bristles occur along the upper beak and are morphologically similar to mammalian whiskers. Mammalian whiskers are important tactile sensors, guiding locomotion, foraging and social interactions, and have a well‐characterised anatomy. However, it is not yet known whether avian rictal bristles have a sensory function, and their morphology, anatomy and function have also not been described in many species. Our study compares bristle morphology, follicle anatomy and their association with foraging traits, across 12 Caprimulgiform species. Rictal bristle morphology and follicle anatomy were diverse across the 12 species. Nine of the 12 species had mechanoreceptors around their bristle follicles; however, there was large variation in their musculature, mechanoreceptor numbers and bristle morphology. Overall, species with short, thin, branching bristles that lacked mechanoreceptors tended to forage pre‐dusk in open habitats, whereas species with mechanoreceptors around their bristle follicle tended to forage at night and in more closed habitats. We suggest that rictal bristles are likely to be tactile in many species and may aid in navigation, foraging and collision avoidance; however, identifying rictal bristle function is challenging and demands further investigation in many species.
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Affiliation(s)
- Mariane G Delaunay
- Department of Natural Sciences, Manchester Metropolitan University, Manchester, UK
| | - Carl Larsen
- School of Life Sciences, University of Liverpool, Liverpool, UK
| | - Huw Lloyd
- Department of Natural Sciences, Manchester Metropolitan University, Manchester, UK
| | - Matthew Sullivan
- Department of Natural Sciences, Manchester Metropolitan University, Manchester, UK
| | - Robyn A Grant
- Department of Natural Sciences, Manchester Metropolitan University, Manchester, UK
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Torres CR, Clarke JA. Nocturnal giants: evolution of the sensory ecology in elephant birds and other palaeognaths inferred from digital brain reconstructions. Proc Biol Sci 2018; 285:20181540. [PMID: 30381378 PMCID: PMC6235046 DOI: 10.1098/rspb.2018.1540] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/10/2018] [Indexed: 11/12/2022] Open
Abstract
The recently extinct Malagasy elephant birds (Palaeognathae, Aepyornithiformes) included the largest birds that ever lived. Elephant bird neuroanatomy is understudied but can shed light on the lifestyle of these enigmatic birds. Palaeoneurological studies can provide clues to the ecologies and behaviours of extinct birds because avian brain shape is correlated with neurological function. We digitally reconstruct endocasts of two elephant bird species, Aepyornis maximus and A. hildebrandti, and compare them with representatives of all major extant and recently extinct palaeognath lineages. Among palaeognaths, we find large olfactory bulbs in taxa generally occupying forested environments where visual cues used in foraging are likely to be limited. We detected variation in olfactory bulb size among elephant bird species, possibly indicating interspecific variation in habitat. Elephant birds exhibited extremely reduced optic lobes, a condition also observed in the nocturnal kiwi. Kiwi, the sister taxon of elephant birds, have effectively replaced their visual systems with hyperdeveloped olfactory, somatosensory and auditory systems useful for foraging. We interpret these results as evidence for nocturnality among elephant birds. Vision was likely deemphasized in the ancestor of elephant birds and kiwi. These results show a previously unreported trend towards decreased visual capacity apparently exclusive to flightless, nocturnal taxa endemic to predator-depauperate islands.
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Affiliation(s)
- Christopher R Torres
- Department of Integrative Biology, University of Texas at Austin, 2415 Speedway, C0930, Austin, TX 78712, USA
| | - Julia A Clarke
- Department of Integrative Biology, University of Texas at Austin, 2415 Speedway, C0930, Austin, TX 78712, USA
- Jackson School of Geosciences, University of Texas at Austin, 2305 Speedway, C1160, Austin, TX 78712, USA
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Stańczyk EK, Velasco Gallego ML, Nowak M, Hatt JM, Kircher PR, Carrera I. 3.0 Tesla magnetic resonance imaging anatomy of the central nervous system, eye, and inner ear in birds of prey. Vet Radiol Ultrasound 2018; 59:705-714. [PMID: 29978528 DOI: 10.1111/vru.12657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 02/18/2018] [Accepted: 03/23/2018] [Indexed: 11/28/2022] Open
Abstract
Despite the increasing interest in the clinical neurology of birds, little is known about the magnetic resonance imaging (MRI) appearance of the avian central nervous system, eye, and inner ear. The objective of this cadaveric study was to document the MRI anatomic features of the aforementioned structures using a high-resolution 3.0 Tesla MRI system. The final study group consisted of 13 cadavers of the diurnal birds of prey belonging to six species. Images were acquired in sagittal, dorsal, and transverse planes using T1-weighted and T2-weighted turbo spin echo sequences. A necropsy with macroscopic analysis of the brain and spinal cord was performed on all cadavers. Microscopic examination of the brain was performed on one cadaver of each species; the spinal cord was examined in three subjects. Anatomic structures were identified on the magnetic resonance images based on histologic slices and available literature. Very good resolution of anatomic detail was obtained. The olfactory bulbs; cerebral hemispheres; diencephalon; optic lobe; cerebellum; pons; ventricular system; optic, trigeminal, and facial nerves; pineal and pituitary glands; as well as the semicircular canals of the inner ear were identified. Exquisite detail was achieved on the ocular structures. In the spinal cord, the gray and white matter differentiation and the glycogen body were identified. This study establishes normal MRI anatomy of the central nervous system, eye, and inner ear of the birds of prey; and may be used as a reference in the assessment of neurologic disorders or visual impairment in this group of birds.
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Affiliation(s)
- Ewa K Stańczyk
- Clinic for Diagnostic Imaging, Vetsuisse Faculty, University of Zurich, 8057, Zurich, Switzerland
| | - María L Velasco Gallego
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, 8057, Zurich, Switzerland
| | - Maricn Nowak
- Department of Pathology, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Wrocław, Poland
| | - Jean-Michel Hatt
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, 8057, Zurich, Switzerland
| | - Patrick R Kircher
- Clinic for Diagnostic Imaging, Vetsuisse Faculty, University of Zurich, 8057, Zurich, Switzerland
| | - Inés Carrera
- Southern Counties Veterinary Specialist, Hangersley, UK
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16
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Blin M, Tine E, Meister L, Elipot Y, Bibliowicz J, Espinasa L, Rétaux S. Developmental evolution and developmental plasticity of the olfactory epithelium and olfactory skills in Mexican cavefish. Dev Biol 2018; 441:242-251. [PMID: 29709597 DOI: 10.1016/j.ydbio.2018.04.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/19/2018] [Accepted: 04/24/2018] [Indexed: 11/16/2022]
Abstract
The fish Astyanax mexicanus comes in two forms: the normal surface-dwelling (SF) and the blind depigmented cave-adapted (CF) morphs. Among many phenotypic differences, cavefish show enhanced olfactory sensitivity to detect amino-acid odors and they possess large olfactory sensory organs. Here, we questioned the relationship between the size of the olfactory organ and olfactory capacities. Comparing olfactory detection abilities of CF, SF and F1 hybrids with various olfactory epithelium (OE) sizes in behavioral tests, we concluded that OE size is not the only factor involved. Other possibilities were envisaged. First, olfactory behavior was tested in SF raised in the dark or after embryonic lens ablation, which leads to eye degeneration and mimics the CF condition. Both absence of visual function and absence of visual organs improved the SF olfactory detection capacities, without affecting the size of their OE. This suggested that developmental plasticity occurs between the visual and the olfactory modalities, and can be recruited in SF after visual deprivation. Second, the development of the olfactory epithelium was compared in SF and CF in their first month of life. Proliferation, cell death, neuronal lifespan, and olfactory progenitor cell cycling properties were identical in the two morphs. By contrast, the proportions of the three main olfactory sensory neurons subtypes (ciliated, microvillous and crypt) in their OE differed. OMP-positive ciliated neurons were more represented in SF, TRPC2-positive microvillous neurons were proportionately more abundant in CF, and S100-positive crypt cells were found in equal densities in the two morphs. Thus, general proliferative properties of olfactory progenitors are identical but neurogenic properties differ and lead to variations in the neuronal composition of the OE in SF and CF. Together, these experiments suggest that there are at least two components in the evolution of cavefish olfactory skills: (1) one part of eye-dependent developmental phenotypic plasticity, which does not depend on the size of the olfactory organ, and (2) one part of developmental evolution of the OE, which may stem from embryonic specification of olfactory neurons progenitor pools.
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Affiliation(s)
- Maryline Blin
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Eugène Tine
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Lydvina Meister
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Yannick Elipot
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Jonathan Bibliowicz
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Luis Espinasa
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Sylvie Rétaux
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France.
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Krause ET, Bischof HJ, Engel K, Golüke S, Maraci Ö, Mayer U, Sauer J, Caspers BA. Olfaction in the Zebra Finch ( Taeniopygia guttata ): What Is Known and Further Perspectives. ADVANCES IN THE STUDY OF BEHAVIOR 2018. [DOI: 10.1016/bs.asb.2017.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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18
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Grigg NP, Krilow JM, Gutierrez-Ibanez C, Wylie DR, Graves GR, Iwaniuk AN. Anatomical evidence for scent guided foraging in the turkey vulture. Sci Rep 2017; 7:17408. [PMID: 29234134 PMCID: PMC5727128 DOI: 10.1038/s41598-017-17794-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 11/30/2017] [Indexed: 12/25/2022] Open
Abstract
The turkey vulture (Cathartes aura) is a widespread, scavenging species in the Western Hemisphere that locates carrion by smell. Scent guided foraging is associated with an expansion of the olfactory bulbs of the brain in vertebrates, but no such neuroanatomical data exists for vultures. We provide the first measurements of turkey vulture brains, including the size of their olfactory bulbs and numbers of mitral cells, which provide the primary output of the olfactory bulbs. Comparative analyses show that the turkey vulture has olfactory bulbs that are 4× larger and contain twice as many mitral cells as those of the sympatric black vulture (Coragyps atratus), despite having brains that are 20% smaller. The turkey vulture has the largest olfactory bulbs in absolute terms and adjusted for brain size among birds, but the number of mitral cells is proportional to the size of their olfactory bulbs. The combination of large olfactory bulbs, high mitral cell counts and a greatly enlarged nasal cavity likely reflects a highly sensitive olfactory system. We suggest that this sensitive sense of smell allowed the turkey vulture to colonize biomes that are suboptimal for scavenging birds and become the most widespread vulture species in the world.
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Affiliation(s)
- Nathan P Grigg
- Department of Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
| | - Justin M Krilow
- Department of Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
| | | | - Douglas R Wylie
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Gary R Graves
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Andrew N Iwaniuk
- Department of Neuroscience, University of Lethbridge, Lethbridge, AB, Canada.
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19
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Corfield JR, Kolominsky J, Craciun I, Mulvany-Robbins BE, Wylie DR. Is Cerebellar Architecture Shaped by Sensory Ecology in the New Zealand Kiwi (Apteryx mantelli). BRAIN, BEHAVIOR AND EVOLUTION 2016; 87:88-104. [PMID: 27192984 DOI: 10.1159/000445315] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 03/09/2016] [Indexed: 11/19/2022]
Abstract
Among some mammals and birds, the cerebellar architecture appears to be adapted to the animal's ecological niche, particularly their sensory ecology and behavior. This relationship is, however, not well understood. To explore this, we examined the expression of zebrin II (ZII) in the cerebellum of the kiwi (Apteryx mantelli), a fully nocturnal bird with auditory, tactile, and olfactory specializations and a reduced visual system. We predicted that the cerebellar architecture, particularly those regions receiving visual inputs and those that receive trigeminal afferents from their beak, would be modified in accordance with their unique way of life. The general stripe-and-transverse region architecture characteristic of birds is present in kiwi, with some differences. Folium IXcd was characterized by large ZII-positive stripes and all Purkinje cells in the flocculus were ZII positive, features that resemble those of small mammals and suggest a visual ecology unlike that of other birds. The central region in kiwi appeared reduced or modified, with folium IV containing ZII+/- stripes, unlike that of most birds, but similar to that of Chilean tinamous. It is possible that a reduced visual system has contributed to a small central region, although increased trigeminal input and flightlessness have undoubtedly played a role in shaping its architecture. Overall, like in mammals, the cerebellar architecture in kiwi and other birds may be substantially modified to serve a particular ecological niche, although we still require a larger comparative data set to fully understand this relationship.
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Affiliation(s)
- Jeremy R Corfield
- Department of Biological Sciences, Salisbury University, Salisbury, Md., USA
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Corfield JR, Price K, Iwaniuk AN, Gutierrez-Ibañez C, Birkhead T, Wylie DR. Diversity in olfactory bulb size in birds reflects allometry, ecology, and phylogeny. Front Neuroanat 2015; 9:102. [PMID: 26283931 PMCID: PMC4518324 DOI: 10.3389/fnana.2015.00102] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 07/13/2015] [Indexed: 12/20/2022] Open
Abstract
The relative size of olfactory bulbs (OBs) is correlated with olfactory capabilities across vertebrates and is widely used to assess the relative importance of olfaction to a species’ ecology. In birds, variations in the relative size of OBs are correlated with some behaviors; however, the factors that have led to the high level of diversity seen in OB sizes across birds are still not well understood. In this study, we use the relative size of OBs as a neuroanatomical proxy for olfactory capabilities in 135 species of birds, representing 21 orders. We examine the scaling of OBs with brain size across avian orders, determine likely ancestral states and test for correlations between OB sizes and habitat, ecology, and behavior. The size of avian OBs varied with the size of the brain and this allometric relationship was for the most part isometric, although species did deviate from this trend. Large OBs were characteristic of more basal species and in more recently derived species the OBs were small. Living and foraging in a semi-aquatic environment was the strongest variable driving the evolution of large OBs in birds; olfaction may provide cues for navigation and foraging in this otherwise featureless environment. Some of the diversity in OB sizes was also undoubtedly due to differences in migratory behavior, foraging strategies and social structure. In summary, relative OB size in birds reflect allometry, phylogeny and behavior in ways that parallel that of other vertebrate classes. This provides comparative evidence that supports recent experimental studies into avian olfaction and suggests that olfaction is an important sensory modality for all avian species.
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Affiliation(s)
- Jeremy R Corfield
- Department of Psychology, University of Alberta, Edmonton AB, Canada ; Department of Neuroscience, University of Lethbridge, Lethbridge AB, Canada
| | - Kasandra Price
- Department of Psychology, University of Alberta, Edmonton AB, Canada
| | - Andrew N Iwaniuk
- Department of Neuroscience, University of Lethbridge, Lethbridge AB, Canada
| | | | - Tim Birkhead
- Department of Animal and Plant Sciences, University of Sheffield Sheffield, UK
| | - Douglas R Wylie
- Department of Psychology, University of Alberta, Edmonton AB, Canada
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Le Duc D, Renaud G, Krishnan A, Almén MS, Huynen L, Prohaska SJ, Ongyerth M, Bitarello BD, Schiöth HB, Hofreiter M, Stadler PF, Prüfer K, Lambert D, Kelso J, Schöneberg T. Kiwi genome provides insights into evolution of a nocturnal lifestyle. Genome Biol 2015; 16:147. [PMID: 26201466 PMCID: PMC4511969 DOI: 10.1186/s13059-015-0711-4] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 07/01/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Kiwi, comprising five species from the genus Apteryx, are endangered, ground-dwelling bird species endemic to New Zealand. They are the smallest and only nocturnal representatives of the ratites. The timing of kiwi adaptation to a nocturnal niche and the genomic innovations, which shaped sensory systems and morphology to allow this adaptation, are not yet fully understood. RESULTS We sequenced and assembled the brown kiwi genome to 150-fold coverage and annotated the genome using kiwi transcript data and non-redundant protein information from multiple bird species. We identified evolutionary sequence changes that underlie adaptation to nocturnality and estimated the onset time of these adaptations. Several opsin genes involved in color vision are inactivated in the kiwi. We date this inactivation to the Oligocene epoch, likely after the arrival of the ancestor of modern kiwi in New Zealand. Genome comparisons between kiwi and representatives of ratites, Galloanserae, and Neoaves, including nocturnal and song birds, show diversification of kiwi's odorant receptors repertoire, which may reflect an increased reliance on olfaction rather than sight during foraging. Further, there is an enrichment of genes influencing mitochondrial function and energy expenditure among genes that are rapidly evolving specifically on the kiwi branch, which may also be linked to its nocturnal lifestyle. CONCLUSIONS The genomic changes in kiwi vision and olfaction are consistent with changes that are hypothesized to occur during adaptation to nocturnal lifestyle in mammals. The kiwi genome provides a valuable genomic resource for future genome-wide comparative analyses to other extinct and extant diurnal ratites.
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Affiliation(s)
- Diana Le Duc
- Institute of Biochemistry, Medical Faculty, University of Leipzig, Johannisallee 30, Leipzig, 04103, Germany.
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, 04103, Germany.
| | - Gabriel Renaud
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, 04103, Germany.
| | - Arunkumar Krishnan
- Department of Neuroscience, Unit of Functional Pharmacology, Uppsala University, Box 593, Husargatan 3, Uppsala, 751 24, Sweden.
| | - Markus Sällman Almén
- Department of Neuroscience, Unit of Functional Pharmacology, Uppsala University, Box 593, Husargatan 3, Uppsala, 751 24, Sweden.
| | - Leon Huynen
- Griffith School of Environment and School of Biomolecular and Physical Sciences, Griffith University, Nathan, Queensland, 4111, Australia.
| | - Sonja J Prohaska
- Department of Computer Science, and Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, 04103, Germany.
| | - Matthias Ongyerth
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, 04103, Germany.
| | - Bárbara D Bitarello
- Department of Genetics and Evolutionary Biology, University of São Paulo, São Paulo, SP, 05508-090, Brazil.
| | - Helgi B Schiöth
- Department of Neuroscience, Unit of Functional Pharmacology, Uppsala University, Box 593, Husargatan 3, Uppsala, 751 24, Sweden.
| | - Michael Hofreiter
- Adaptive Evolutionary Genomics, Institute for Biochemistry and Biology, University Potsdam, Potsdam, 14469, Germany.
| | - Peter F Stadler
- Department of Computer Science, and Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, 04103, Germany.
| | - Kay Prüfer
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, 04103, Germany.
| | - David Lambert
- Griffith School of Environment and School of Biomolecular and Physical Sciences, Griffith University, Nathan, Queensland, 4111, Australia.
| | - Janet Kelso
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, 04103, Germany.
| | - Torsten Schöneberg
- Institute of Biochemistry, Medical Faculty, University of Leipzig, Johannisallee 30, Leipzig, 04103, Germany.
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Corfield JR, Kolominsky J, Marin GJ, Craciun I, Mulvany-Robbins BE, Iwaniuk AN, Wylie DR. Zebrin II Expression in the Cerebellum of a Paleognathous Bird, the Chilean Tinamou (Nothoprocta perdicaria). BRAIN, BEHAVIOR AND EVOLUTION 2015; 85:94-106. [DOI: 10.1159/000380810] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 02/09/2015] [Indexed: 11/19/2022]
Abstract
Zebrin II (ZII) is a glycolytic enzyme expressed in cerebellar Purkinje cells. In both mammals and birds, ZII is expressed heterogeneously, such that there are sagittal stripes of Purkinje cells with a high ZII expression (ZII+) alternating with stripes of Purkinje cells with little or no expression (ZII-). To date, ZII expression studies are limited to neognathous birds: pigeons (Columbiformes), chickens (Galliformes), and hummingbirds (Trochilidae). These previous studies divided the avian cerebellum into 5 transverse regions based on the pattern of ZII expression. In the lingular region (lobule I) all Purkinje cells are ZII+. In the anterior region (lobules II-V) there are 4 pairs of ZII+/- stripes. In the central region (lobules VI-VIII) all Purkinje cells are ZII+. In the posterior region (lobules VIII-IX) there are 5-7 pairs of ZII+/- stripes. Finally, in the nodular region (lobule X) all Purkinje cells are ZII+. As the pattern of ZII stripes is quite similar in these disparate species, it appears that it is highly conserved. However, it has yet to be studied in paleognathous birds, which split from the neognaths over 100 million years ago. To better understand the evolution of cerebellar compartmentation in birds, we examined ZII immunoreactivity in a paleognath, the Chilean tinamou (Nothoprocta perdicaria). In the tinamou, Purkinje cells expressed ZII heterogeneously such that there were sagittal ZII+ and ZII- stripes of Purkinje cells, and this pattern of expression was largely similar to that observed in neognathous birds. For example, all Purkinje cells in the lingular (lobule I) and nodular (lobule X) regions were ZII+, and there were 4 pairs of ZII+/- stripes in the anterior region (lobules II-V). In contrast to neognaths, however, ZII was expressed in lobules VI-VII as a series of sagittal stripes in the tinamou. Also unlike in neognaths, stripes were absent in lobule IXab, and all Purkinje cells expressed ZII in the tinamou. The differences in ZII expression between the tinamou and neognaths could reflect behavior, but the general similarity of the expression patterns across all bird species suggests that ZII stripes evolved early in the avian phylogenetic tree.
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Corfield JR, Parsons S, Harimoto Y, Acosta ML. Retinal anatomy of the New Zealand kiwi: structural traits consistent with their nocturnal behavior. Anat Rec (Hoboken) 2014; 298:771-9. [PMID: 25346176 DOI: 10.1002/ar.23080] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 09/10/2014] [Accepted: 09/20/2014] [Indexed: 11/09/2022]
Abstract
Kiwi (Apteryx spp.) have a visual system unlike that of other nocturnal birds, and have specializations to their auditory, olfactory, and tactile systems. Eye size, binocular visual fields and visual brain centers in kiwi are proportionally the smallest yet recorded among birds. Given the many unique features of the kiwi visual system, we examined the laminar organization of the kiwi retina to determine if they evolved increased light sensitivity with a shift to a nocturnal niche or if they retained features of their diurnal ancestor. The laminar organization of the kiwi retina was consistent with an ability to detect low light levels similar to that of other nocturnal species. In particular, the retina appeared to have a high proportion of rod photoreceptors as compared to diurnal species, as evidenced by a thick outer nuclear layer, and also numerous thin photoreceptor segments intercalated among the conical shaped cone photoreceptor inner segments. Therefore, the retinal structure of kiwi was consistent with increased light sensitivity, although other features of the visual system, such as eye size, suggest a reduced reliance on vision. The unique combination of a nocturnal retina and smaller than expected eye size, binocular visual fields, and brain regions make the kiwi visual system unlike that of any bird examined to date. Whether these features of their visual system are an evolutionary design that meets their specific visual needs or are a remnant of a kiwi ancestor that relied more heavily on vision is yet to be determined.
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Affiliation(s)
- Jeremy R Corfield
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
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