Morphology, ontogenesis and mechanics of cervical vertebrae in four species of penguins (Aves: Spheniscidae)

Guinard, Geoffrey; Marchand, Didier; Courant, Frédéric; Gauthier‐Clerc, Michel; Bohec, Céline Le

doi:10.1007/s00300-009-0759-2

Cited by 18 publications

(21 citation statements)

References 11 publications

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“…Com exceção do atlas e áxis, todas as outras vértebras cervicais apresentaram processos costais (Fig.2), maiores principalmente em C7 e C8 (Guinard et al, 2010). Também, foram encontrados processos espinhosos bem desenvolvidos de C2 a C5 e, principalmente, na última vértebra cervical (C11 ou C12), enquanto que de C6 a C10, este processo se pareceu mais como uma crista pouco elevada (Baumel 1993).…”

Section: Resultsunclassified

Descrição anatômica de esqueletos de papagaios do gênero Amazona através da utilização de radiografias

Cavinatto

Armando²,

Cruz

et al. 2016

Pesq. Vet. Bras.

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RESUMO.-O esqueleto de papagaios da espécie Amazona aestiva foi descrito e comparado com representantes de outras espécies do gênero Amazona. Para tanto, foram utilizados 22 exemplares da espécie Amazona aestiva; dois das espécies Amazona vinacea; Amazona rhodocorythae, Amazona farinosa, além de um exemplar das espécies Amazona brasiliensis e Amazona pretrei, doados após morte natural pelo Criadouro Poços de Caldas. Foram realizadas radiografias de corpo inteiro, variando de decúbito lateral direito ou esquerdo, no caso das projeções latero-laterais, e em decúbito dorsal, no caso da projeção ventro-dorsal. Independentemente da espécie, os crânios dos papagaios estudados puderam ser classificados como pró-cinéticos, por apresentarem liberdade de movimentos em sua porção rostral. Na maioria dos casos, a coluna vertebral esteve formada por 12 vértebras cervicais, seis vértebras torácicas livres, sinsacro (formado pela fusão da última vértebra torácica, 7 lombosacrais e uma caudal), cinco vértebras caudais livres e pelo pigóstilo (formado por três vértebras caudais fusionadas) e, apesar de diferenças pontuais, o esqueleto apendicular torácico e pélvico se mostrou muito semelhante ao observado para outros gêneros de aves e, inclusive, não foi possí-vel observar dimorfismo sexual através das características anatômicas dos esqueletos dos papagaios trabalhados. This study describes the skeleton of Amazona aestiva parrots and compared it with representatives of other Amazona species. To this end, we used 22 specimens of Amazona aestiva, two specimens each of Amazona vinacea; Amazona rhodocorythae, Amazona farinosa and one specimen each of Amazona brasiliensis and Amazona pretrei donated after natural death by Poços de Caldas Breeding Park. Full body radiographs were taken, in either the right or left lateral decubitus position, in the case of laterolateral projections, and in supine position, in the case of ventrodorsal projection. Regardless of the species, skulls of the parrots were classified as prokinetic, because of free movements in their rostral portion. In most cases, the spine consisted of: 12 cervical vertebrae, six free thoracic vertebrae, synsacrum (formed by the fusion of the last thoracic vertebrae, 7 lumbosacral vertebrae and one caudal vertebrae), five free caudal vertebrae and the pygostyle (formed by three fused caudal vertebrae). Despite punctual differences, thoracic and pelvic appendicular skeleton proved to be very similar to that observed for other genera of birds. In addition, there was no sexual dimorphism considering the anatomical characteristics of the skeletons of parrots analyzed.

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Section: Resultsunclassified

Descrição anatômica de esqueletos de papagaios do gênero Amazona através da utilização de radiografias

Cavinatto

Armando²,

Cruz

et al. 2016

Pesq. Vet. Bras.

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“…8). This variation of identity during the growth of the chick has been identified in Aptenodytes patagonicus and Pygoscelis papua from ontogenetic follow-up of several individuals at different stages of growth (Guinard et al 2010).…”

Section: Identification Of Two Types Of Homeotic Transformationsmentioning

confidence: 99%

“…In addition, there is a pair of strong processus caroticus, which for Simpson, is found on C VII or C VIII of the extant representatives. From the previous study of penguins (Guinard et al 2010), it is considered that the true 1 processus caroticus appear for Aptenodytes patagonicus and Spheniscus humboldti on C VII and for Pygoscelis papua and Eudyptes chrysolophus on C VI, thus just after the transitional vertebra. In this context, the cervical defined as C VI by Simpson is effectively the sixth.…”

Section: The Contribution Of Fossil Materialsmentioning

confidence: 99%

“…Considering the measurements, and compared with those made in the previous study (Guinard et al 2010), the first variable, ''width between prezygapohyses''-or zygapophysis cranialis-is our front width 1 (Fw1), and the second variable ''Length of centrum'' is our Length 4 (L4) (Fig. 2).…”

Section: The Contribution Of Fossil Materialsmentioning

confidence: 99%

“…Mechanical folding of the neck is important in penguins, as it allows the head to connect with the thorax during swimming (''underwater flight''), and on land, this folding is used to maintain the balance of erect posture. This lack of consideration was corrected in a previous study (Guinard et al 2010) devoted to the cervical system of four species of extant penguins: Aptenodytes patagonicus, Pygoscelis papua, Eudyptes chrysolophus, and Spheniscus humboldti.…”

Section: Introductionmentioning

confidence: 95%

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Modularity and Complete Natural Homeoses in Cervical Vertebrae of Extant and Extinct Penguins (Aves: Sphenisciformes)

Guinard¹,

Marchand²

2010

Evol Biol

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The cervical system of extant penguins (Aves: Sphenisciformes) is organised into morphological modules, each with its biomechanical function. Indeed, for these marine pelagic birds to acquire hydrodynamic morphology, the folding of the neck is essential. Despite a common general structure, the cervical vertebrae exhibit morphological differences depending on their positioning. These characteristics are identified as apparent cases of complete natural homeotic transformations-therefore, the composition of some modules varies. Two types of complete cervical homeoses are identified between species, but the second type can also occur within some species when the post hatching development is considered. The fossil material analysed here makes it apparent that the two modular configurations characterising the anterior part of the neck-a consequence of the first homeosis-existed 36 My and 25 My ago, for one, and circa 10 My ago, for the other. These comparisons also reveal a clear differentiation in vertebral features between the fossil species of the Oligocene-Miocene ages and the more recent and extant penguins. Ultimately, these observations make the proposal of a hypothesis in relation to the ontogenetic influence of Hox genes, and their regulators, based on the changes observed in the cervical segment of Sphenisciformes.

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Cervical anatomy and its relation to foraging habits in aquatic birds (Aves: Neornithes: Neoaves)

Buchmann,

Rodrigues

2024

The Anatomical Record

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Birds have extremely flexible necks, which help in their search for food. However, studies on the variation in bird cervical anatomy and its relationship with foraging are rare, despite the different habits presented between species. Here, we analyze the anatomy of the neck of aquatic birds and relate it to their foraging strategies. We dissected specimens representing four species of Charadriiformes, 11 species of Phaethoquornithes, and two specimens belonging to the outgroup Telluraves. We chose to emphasize Charadriiformes and Phaethoquornithes because they present several strategies that require cervical mobility and stability. We note that vertebral anatomy and dimensions vary, which affects the shape and size of the soft tissues attached throughout the neck. The synovial cartilage present in the articulatio intercorporalis represents an additional length in the neck, however, this is not longer than that observed in animals with intervertebral discs. Our analysis indicates that birds have a prevalence of dorsoventral movements in the middle of the neck and lateral and rotational movements near the base of the neck, while the region near the head presents a wide range of movement in all directions. Cervical ligaments and muscles throughout the neck provide stability in all segments, although the robustness of the soft tissues indicates that the most caudal portion of the neck is the most stable. The vertebral and soft tissue anatomy is consistent with the extensive mobility in pitching, yaw, and roll movements performed mainly by the head and first segment of the neck during the different foraging of the analyzed birds. Furthermore, the muscles closer to the skull are robust and allow the execution of a variety of habits to capture food in different species. The subsequent cervical segments present differences that explain their reduction in mobility, but they are equally stable.

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Morphology, ontogenesis and mechanics of cervical vertebrae in four species of penguins (Aves: Spheniscidae)

Cited by 18 publications

References 11 publications

Descrição anatômica de esqueletos de papagaios do gênero Amazona através da utilização de radiografias

Descrição anatômica de esqueletos de papagaios do gênero Amazona através da utilização de radiografias

Modularity and Complete Natural Homeoses in Cervical Vertebrae of Extant and Extinct Penguins (Aves: Sphenisciformes)

Cervical anatomy and its relation to foraging habits in aquatic birds (Aves: Neornithes: Neoaves)

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