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1.
Commun Biol ; 5(1): 1205, 2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36414754

RESUMO

There are many hypotheses explaining the diversity of colours and patterns found in nature, but they are often difficult to examine empirically. Recent studies show the dark upperside of gliding birds' wings could reduce drag by decreasing the density of surrounding air. It may therefore be expected that species with darker wings have less efficient morphology than their paler counterparts. I conducted an analysis of the Larinae (gulls), which exhibit extreme variation in wing (mantle and wingtip) melanization, to test whether wing loading is a predictor of wing darkness. I found that, for each standard deviation increase in wing loading, mantle darkness is predicted to increase by 1.2 shades on the Kodak grey scale. Wing loading is also positively related to the proportion of black on wingtips. Furthermore, heavier species have lower aspect ratio wings, suggesting that dark wings have evolved to improve the trade-off between maneuverability and long distance flight.


Assuntos
Charadriiformes , Besouros , Animais , Voo Animal , Asas de Animais/anatomia & histologia , Pigmentação , Aves/anatomia & histologia
2.
Nature ; 611(7935): 306-311, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36289328

RESUMO

Characterizing how variation in the tempo and mode of evolution has structured the phenotypic diversity of extant species is a central goal of macroevolution1-3. However, studies are typically limited to a handful of traits4-6, providing incomplete information. We analyse morphological diversification in living birds, an ecologically diverse group7, documenting structural scales from 'pan-skeletal' proportions down to the localized three-dimensional shape changes of individual bones. We find substantial variation in evolutionary modes among avian subgroups and among skeletal parts, indicating widespread mosaicism and possible differences in the structure of the macroevolutionary landscape across Earth's main environments. Water-linked groups, especially Aequorlitornithes (waterbirds), have repeatedly explored a large portion of their total morphospace, emphasizing variation in body proportions and in the shape of bones close to the body core, which are functionally related to the mechanics of locomotion8. By contrast, landbirds (Inopinaves) evolved distinct, group-specific body forms early in the aftermath of the K-Pg and subsequently emphasized local shape variation, especially in the head and distal limb bones, which interact more directly with the environment. Passerines, which comprise more than half of all bird species, show a conservative evolutionary dynamic that resulted in low disparity across all skeletal parts. Evidence for early establishment of the morphospace of living birds is clear for some skeletal parts, including beaks and the combined skeletal morphology. However, we find little evidence for early partitioning of that morphospace, contrary to more specific predictions of 'niche-filling' models1,9. Nevertheless, early divergence among broad environmental types may have caused an early divergence of evolutionary modes, suggesting an important role for environmental divergence in structuring the radiation of crown-group birds.


Assuntos
Evolução Biológica , Aves , Meio Ambiente , Fenótipo , Esqueleto , Animais , Aves/anatomia & histologia , Aves/classificação , Extremidades/anatomia & histologia , Locomoção , Esqueleto/anatomia & histologia , Mosaicismo , Bico
3.
Curr Biol ; 32(20): R1173-R1186, 2022 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-36283387

RESUMO

Organismal adaptations are the hallmark of natural selection. Studies of adaptations in avian systems have been central to key conceptual and empirical advances in the field of evolutionary biology and, over the past decade, leveraged the proliferation of a diversity of genomic tools. In this synthesis, we first discuss how the different genomic architectures of avian traits are relevant to adaptive phenotypes. A mutation's chromosomal location (e.g., microchromosomes or sex chromosomes) or its specific nature (e.g., nucleotide substitution or structural variant) will determine how it may evolve and shape adaptive phenotypes, and we review different examples from the avian literature. We next describe how the source of adaptive variation, whether from de novo mutations, existing genetic variation, or introgression from another species, can affect the evolutionary dynamics of a trait. Our third section reviews case studies where the genetic basis of key avian adaptive phenotypes (e.g., bill morphology or plumage coloration) have been revealed. We end by providing an outlook and identifying important challenges to this field, both by focusing on technical aspects, such as the completeness of genomic assemblies and the ability to validate genetic associations with new sources of data, as well as by discussing the existential threat posed to birds from habitat alteration and climate change.


Assuntos
Aves , Genômica , Animais , Aves/genética , Aves/anatomia & histologia , Seleção Genética , Cromossomos Sexuais , Nucleotídeos
4.
Proc Biol Sci ; 289(1983): 20221398, 2022 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-36168759

RESUMO

Among terrestrial vertebrates, only crown birds (Neornithes) rival mammals in terms of relative brain size and behavioural complexity. Relatedly, the anatomy of the avian central nervous system and associated sensory structures, such as the vestibular system of the inner ear, are highly modified with respect to those of other extant reptile lineages. However, a dearth of three-dimensional Mesozoic fossils has limited our knowledge of the origins of the distinctive endocranial structures of crown birds. Traits such as an expanded, flexed brain, a ventral connection between the brain and spinal column, and a modified vestibular system have been regarded as exclusive to Neornithes. Here, we demonstrate all of these 'advanced' traits in an undistorted braincase from an Upper Cretaceous enantiornithine bonebed in southeastern Brazil. Our discovery suggests that these crown bird-like endocranial traits may have originated prior to the split between Enantiornithes and the more crownward portion of avian phylogeny over 140 Ma, while coexisting with a remarkably plesiomorphic cranial base and posterior palate region. Altogether, our results support the interpretation that the distinctive endocranial morphologies of crown birds and their Mesozoic relatives are affected by complex trade-offs between spatial constraints during development.


Assuntos
Dinossauros , Orelha Interna , Animais , Evolução Biológica , Aves/anatomia & histologia , Encéfalo , Dinossauros/anatomia & histologia , Orelha Interna/anatomia & histologia , Fósseis , Mamíferos , Filogenia , Base do Crânio/anatomia & histologia
5.
Am Nat ; 200(4): E174-E188, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36150203

RESUMO

AbstractAvian skull shape diversity is classically thought to result from selection for structures that are well adapted for distinct ecological functions, but recent work has suggested that allometry is the dominant contributor to avian morphological diversity. If true, this hypothesis would overturn much conventional wisdom regarding the importance of form-function relationships in adaptive radiations, but it is possible that these results are biased by the low taxonomic levels of the clades that have been studied. Using 3D morphometric data from the skulls of a relatively old and ecologically diverse order of birds, the Charadriiformes (shorebirds and relatives), we found that foraging ecology explains more than two-thirds of the variation in skull shape across the clade. However, we also found support for the hypothesis that skull allometry evolves, contributing more to shape variation at the level of the family than the order. Allometry may provide an important source of shape variation on which selection can act over short timescales, but its potential to evolve complicates generalizations between clades. Foraging ecology remains a better predictor of avian skull shape over macroevolutionary timescales.


Assuntos
Evolução Biológica , Crânio , Animais , Aves/anatomia & histologia , Cabeça , Filogenia , Crânio/anatomia & histologia
6.
J Morphol ; 283(12): 1483-1504, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36062802

RESUMO

Nectar-feeding birds provide an excellent system in which to examine form-function relationships over evolutionary time. There are many independent origins of nectarivory in birds, and nectar feeding is a lifestyle with many inherent biophysical constraints. We review the morphology and function of the feeding apparatus, the locomotor apparatus, and the digestive and renal systems across avian nectarivores with the goals of synthesizing available information and identifying the extent to which different aspects of anatomy have morphologically and functionally converged. In doing so, we have systematically tabulated the occurrence of putative adaptations to nectarivory across birds and created what is, to our knowledge, the first comprehensive summary of adaptations to nectarivory across body systems and taxa. We also provide the first phylogenetically informed estimate of the number of times nectarivory has evolved within Aves. Based on this synthesis of existing knowledge, we identify current knowledge gaps and provide suggestions for future research questions and methods of data collection that will increase our understanding of the distribution of adaptations across bodily systems and taxa, and the relationship between those adaptations and ecological and evolutionary factors. We hope that this synthesis will serve as a landmark for the current state of the field, prompting investigators to begin collecting new data and addressing questions that have heretofore been impossible to answer about the ecology, evolution, and functional morphology of avian nectarivory.


Assuntos
Aves , Néctar de Plantas , Animais , Aves/anatomia & histologia , Filogenia
7.
Zootaxa ; 5168(1): 39-50, 2022 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-36101302

RESUMO

A large fossil anserine-like anatid (Aves, Anatidae, Notochen bannockburnensis gen. et sp. nov.) is described based on a distal humerus from the lower Bannockburn Formation, early Miocene (1916 Ma), St Bathans Fauna from New Zealand. Its morphology and size suggest that this taxon represents an early swan rather than a goose. Extant anserines are split into Northern and Southern Hemisphere clades. The St Bathans Fauna is known to have the oldest anserines in the Southern Hemisphere, unnamed cereopsines perhaps ancestral to species of Cnemiornis (New Zealand geese). The elongate and flat morphology of the tuberculum supracondylare ventrale of the new species, however, preclude affinities with cereopsines. It is a rare taxon and the eighth anatid represented in the fauna and is the largest known anseriform from the Oligo-Miocene of Australasia. We also reassess other large anatid specimens from the St Bathans Fauna and identify Miotadorna catrionae Tennyson, Greer, Lubbe, Marx, Richards, Giovanardi Rawlence, 2022 as a junior synonym of Miotadorna sanctibathansi Worthy, Tennyson, Jones, McNamara Douglas, 2007.


Assuntos
Anseriformes , Fósseis , Animais , Aves/anatomia & histologia , Nova Zelândia , Filogenia
8.
Commun Biol ; 5(1): 857, 2022 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-35999361

RESUMO

The New World Vulture [Coragyps] occidentalis (L. Miller, 1909) is one of many species that were extinct by the end of the Pleistocene. To understand its evolutionary history we sequenced the genome of a 14,000 year old [Coragyps] occidentalis found associated with megaherbivores in the Peruvian Andes. occidentalis has been viewed as the ancestor, or possibly sister, to the extant Black Vulture Coragyps atratus, but genomic data shows occidentalis to be deeply nested within the South American clade of atratus. Coragyps atratus inhabits lowlands, but the fossil record indicates that occidentalis mostly occupied high elevations. Our results suggest that occidentalis evolved from a population of atratus in southwestern South America that colonized the High Andes 300 to 400 kya. The morphological and morphometric differences between occidentalis and atratus may thus be explained by ecological diversification following from the natural selection imposed by this new and extreme, high elevation environment. The sudden evolution of a population with significantly larger body size and different anatomical proportions than atratus thus constitutes an example of punctuated evolution.


Assuntos
Aves , Fósseis , Animais , Aves/anatomia & histologia , América do Sul
9.
J Anat ; 241(4): 966-980, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35938671

RESUMO

Ibises (order: Pelecaniformes, family: Threskiornithidae) are probe-foraging birds that use 'remote-touch' to locate prey items hidden in opaque substrates. This sensory capability allows them to locate their prey using high-frequency vibrations in the substrate in the absence of other sensory cues. Remote-touch is facilitated by a specialised bill-tip organ, comprising high densities of mechanoreceptors (Herbst corpuscles) embedded in numerous foramina in the beak bones. Each foramen and its associated Herbst corpuscles make up a sensory unit, called a 'sensory pit'. These sensory pits are densely clustered in the distal portion of the beak. Previous research has indicated that interspecific differences in the extent of sensory pitting in the beak bones correlate with aquatic habitat use of ibises, and have been suggested to reflect different levels of remote-touch sensitivity. Our study investigates the interspecific differences in the bone and soft tissue histology of the bill-tip organs of three species of southern African ibises from different habitats (mainly terrestrial to mainly aquatic). We analysed the external pitting pattern on the bones, as well as internal structure of the beak using micro-CT scans and soft tissue histological sections of each species' bill-tip organs. The beaks of all three species contain remote-touch bill-tip organs and are described here in detail. Clear interspecific differences are evident between the species' bill-tip organs, both in terms of bone morphology and soft tissue histology. Glossy Ibises, which forage exclusively in wetter substrates, have a greater extent of pitting but lower numbers of Herbst corpuscles in each pit, while species foraging in drier substrates (Hadeda and Sacred Ibises) have more robust beaks, fewer pits and higher densities of Herbst corpuscles. Our data, together with previously published histological descriptions of the bill-tip organs of other remote-touch foraging bird species, indicate that species foraging in drier habitats have more sensitive bill-tip organs (based on their anatomy). The vibrations produced by prey (e.g., burrowing invertebrates) travel poorly in dry substrates compared with wetter ones (i.e., dry soil vs. mud or water), and thus we hypothesise that a more sensitive bill-tip organ may be required to successfully locate prey in dry substrates. Furthermore, our results indicate that the differences in bill-tip organ anatomy between the species reflect complex trade-offs between morphological constraints of beak shape and remote-touch sensitivity requirements, both of which are likely related to each species' foraging behaviour and substrate usage. Our study suggests that structures in the bone of the bill-tip organ could provide valuable osteological correlates for the associated soft tissues, and consequently may provide information on the sensory ecology and habitat usage of the birds in the absence of soft tissues.


Assuntos
Bico/anatomia & histologia , Aves/anatomia & histologia , Tato , África Austral , Animais , Bico/fisiologia , Aves/fisiologia , Mecanorreceptores/fisiologia , Solo , Tato/fisiologia , Vibração , Água
10.
J Anat ; 241(6): 1387-1398, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35981708

RESUMO

Postcranial skeletal pneumaticity, air-filled bones of the trunk and limbs, is exclusive to birds among extant tetrapods and exhibits significant variation in its expression among different species. Such variation is not random but exhibits relationships with both body mass and locomotor specializations. Most species-level comparative research to date has focused on aquatic-oriented taxa (e.g., Anseriformes). The lack of data from non-aquatic birds constrains our ability to characterize global (i.e., avian-wide) patterns of this trait complex. To address this gap, the study conducted herein quantified postcranial pneumaticity in Accipitrimorphae, a mostly terrestrial clade composed of species that span a range of body sizes and exhibit diverse flight/foraging behaviors. All examined species (n = 88) invariably pneumatized the postaxial through pre-caudal vertebrae, sternum, coracoid, humerus, vertebral and sternal ribs, and pelvic girdle, a pattern herein referred to as the accipitrimorph baseline. Of the 88 sampled species, 41 expanded upon this pattern, whereas 10 species exhibited a reduction. No species deviated from the accipitrimorph baseline by more than two anatomical regions. A phylogenetically-informed regression analysis failed to identify a significant relationship between body mass and pneumaticity. However, specific pneumaticity phenotypes deviating from the baseline were correlated with aspects of wing morphology, tail length, and home range size. Results from this and previous studies provide clarity on two hypotheses: (1) aquatic taxa display distinct pneumaticity expression patterns relative to non-aquatic birds, notably with reductions in the proportion of the skeleton filled with air in diving specialists and (2) contemporary comparative studies, including the one herein, that explicitly account for phylogenetic relationships consistently fail to support the oft-cited positive relationship between pneumaticity and body mass. Instead, historical relationships and functional/ecological attributes (e.g., diving, specialized flight behaviors) appear to be the primary drivers underlying patterns of variation in this trait complex.


Assuntos
Aves , Osso e Ossos , Animais , Filogenia , Aves/anatomia & histologia , Coluna Vertebral/anatomia & histologia , Tamanho Corporal , Evolução Biológica
11.
Nature ; 608(7922): 346-352, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35896745

RESUMO

Living birds (Aves) have bodies substantially modified from the ancestral reptilian condition. The avian pelvis in particular experienced major changes during the transition from early archosaurs to living birds1,2. This stepwise transformation is well documented by an excellent fossil record2-4; however, the ontogenetic alterations that underly it are less well understood. We used embryological imaging techniques to examine the morphogenesis of avian pelvic tissues in three dimensions, allowing direct comparison with the fossil record. Many ancestral dinosaurian features2 (for example, a forward-facing pubis, short ilium and pubic 'boot') are transiently present in the early morphogenesis of birds and arrive at their typical 'avian' form after transitioning through a prenatal developmental sequence that mirrors the phylogenetic sequence of character acquisition. We demonstrate quantitatively that avian pelvic ontogeny parallels the non-avian dinosaur-to-bird transition and provide evidence for phenotypic covariance within the pelvis that is conserved across Archosauria. The presence of ancestral states in avian embryos may stem from this conserved covariant relationship. In sum, our data provide evidence that the avian pelvis, whose early development has been little studied5-7, evolved through terminal addition-a mechanism8-10 whereby new apomorphic states are added to the end of a developmental sequence, resulting in expression8,11 of ancestral character states earlier in that sequence. The phenotypic integration we detected suggests a previously unrecognized mechanism for terminal addition and hints that retention of ancestral states in development is common during evolutionary transitions.


Assuntos
Aves , Dinossauros , Desenvolvimento Embrionário , Fósseis , Pelve , Filogenia , Animais , Aves/anatomia & histologia , Aves/classificação , Aves/embriologia , Dinossauros/anatomia & histologia , Dinossauros/embriologia , Imageamento Tridimensional , Pelve/anatomia & histologia , Pelve/embriologia
12.
Science ; 377(6605): 458, 2022 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-35901145

RESUMO

Two studies predict homogenization of the avian world as climate change and other human impacts continue.


Assuntos
Efeitos Antropogênicos , Aves , Mudança Climática , Extinção Biológica , Animais , Aves/anatomia & histologia , Humanos
13.
Science ; 376(6600): eabl6710, 2022 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-35737763

RESUMO

Hanson et al. (Research Articles, 7 May 2021, p. 601) claim that the shape of the vestibular apparatus reflects the evolution of reptilian locomotion. Using biomechanics, we demonstrate that semicircular canal shape is a dubious predictor of semicircular duct function. Additionally, we show that the inference methods used by Hanson et al. largely overestimate relationships between semicircular canal shape and locomotion.


Assuntos
Evolução Biológica , Aves , Dinossauros , Locomoção , Canais Semicirculares , Animais , Aves/anatomia & histologia , Dinossauros/anatomia & histologia , Dinossauros/fisiologia , Canais Semicirculares/anatomia & histologia
14.
Science ; 376(6600): eabl8181, 2022 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-35737783

RESUMO

David et al. claim that vestibular shape does not reflect function and that we did not use phylogenetic inference methods in our primary analyses. We show that their claims are countered by comparative and direct experimental evidence from across Vertebrata and that their models are empirically unverified. We did use phylogenetic methods to test our hypotheses. Moreover, their phylogenetic correction attempts are methodologically inappropriate.


Assuntos
Evolução Biológica , Aves , Dinossauros , Locomoção , Canais Semicirculares , Vocalização Animal , Animais , Aves/anatomia & histologia , Aves/fisiologia , Dinossauros/anatomia & histologia , Dinossauros/fisiologia , Filogenia , Canais Semicirculares/anatomia & histologia
15.
J Anim Ecol ; 91(8): 1651-1665, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35668666

RESUMO

Substantial global data show that many taxa are shifting their phenologies in response to climate change. For birds, migration arrival dates in breeding regions have been shifting earlier, and there is evidence that both evolutionary adaptation and behavioural flexibility influence these shifts. As more efficient flyers may be able to demonstrate more flexibility to respond to changing conditions during migratory flight, we hypothesize that differences among passerine species in flight efficiency, as reflected by morphology, may be associated with the magnitude of shifts in arrival date in response to climate warming. We applied a logistic model to 18 years of eBird data to estimate mean arrival date for 44 common passerines migrating to northeast North America. We then used linear mixed-effects models to estimate changes in mean arrival date and compared these changes to morphological proxies for flight efficiency and migratory distance using phylogenetic generalized least squares models. On average, passerine species shifted their arrival dates 0.120 days earlier each year, with 27 of the 44 species shifting to significantly earlier arrival times, and two shifting to significantly later ones. Of the 15 species with non-significant shifts, 13 trended toward earlier arrivals. Longer migration distances and higher wing aspect ratios were associated with greater shifts toward earlier arrivals. Migration distance and aspect ratio were also significantly correlated to each other. This suggests that changes in arrival date are affected by factors pertaining to migratory flight over long distances namely, flight efficiency and migration distance. These traits may be able predict the magnitude of arrival date shift, and by extension identify species that are most at risk to climate change due to inflexible arrival timing.


Assuntos
Migração Animal , Aves/fisiologia , Mudança Climática , Voo Animal/fisiologia , Asas de Animais/anatomia & histologia , Animais , Evolução Biológica , Aves/anatomia & histologia , Aves/classificação , Filogenia , Estações do Ano , Fatores de Tempo , Asas de Animais/fisiologia
16.
Proc Biol Sci ; 289(1976): 20220675, 2022 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-35642364

RESUMO

A link between diet and avian intestinal anatomy is generally assumed. We collated the length of intestinal sections and body mass of 390 bird species and tested relationships with diet, climate and locomotion. There was a strong phylogenetic signal in all datasets. The total and small intestine scaled more-than-geometrically (95%CI of the scaling exponent > 0.33). The traditional dietary classification (faunivore, omnivore and herbivore) had no significant effect on total intestine (TI) length. Significant dietary proxies included %folivory, %frugi-nectarivory and categories (frugi-nectarivory, granivory, folivory, omnivory, insectivory and vertivory). Individual intestinal sections were affected by different dietary proxies. The best model indicates that higher consumption of fruit and nectar, drier habitats, and a high degree of flightedness are linked to shorter TI length. Notably, the length of the avian intestine depends on other biological factors as much as on diet. Given the weak dietary signal in our datasets, the diet intestinal length relationships lend themselves to narratives of flexibility (morphology is not destiny) rather than of distinct adaptations that facilitate using one character (intestine length) as proxy for another (diet). Birds have TIs of about 85% that of similar-sized mammals, corroborating systematic differences in intestinal macroanatomy between vertebrate clades.


Assuntos
Aves , Intestinos , Animais , Aves/anatomia & histologia , Dieta/veterinária , Ecossistema , Mamíferos , Filogenia , Especificidade da Espécie
17.
J Anat ; 241(3): 776-788, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35608388

RESUMO

Studies have suggested that the brain morphology and flight ability of Aves are interrelated; however, such a relationship has not been thoroughly investigated. This study aimed to examine whether flight ability, volant or flightless, affects brain morphology (size and shape) in the Rallidae, which has independently evolved to adapt secondary flightlessness multiple times within a single taxonomic group. Brain endocasts were extracted from computed tomography images of the crania, measured by 3D geometric morphometrics, and were analyzed using principal component analysis. The results of phylogenetic ANCOVA showed that flightless rails have brain sizes and shapes that are significantly larger than and different from those of volant rails, even after considering the effects of body mass and brain size respectively. Flightless rails tended to have a wider telencephalon and more inferiorly positioned foramen magnum than volant rails. Although the brain is an organ that requires a large amount of metabolic energy, reduced selective pressure for a lower body weight may have allowed flightless rails to have larger brains. The evolution of flightlessness may have changed the position of the foramen magnum downward, which would have allowed the support of the heavier cranium. The larger brain may have facilitated the acquisition of cognitively advanced behavior, such as tool-using behavior, among rails.


Assuntos
Aves , Crânio , Animais , Aves/anatomia & histologia , Encéfalo/anatomia & histologia , Encéfalo/diagnóstico por imagem , Filogenia , Análise de Componente Principal , Crânio/diagnóstico por imagem
18.
Avian Pathol ; 51(4): 381-387, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35503252

RESUMO

Perineuronal or neuronal satellitosis is the term describing the presence of glial cells in the satellite space surrounding the neuronal perikaryon. Confusingly, this finding has been described both as a physiologic and pathologic condition in humans and animals. In animals, neuronal satellitosis has been described in mammals, as well as in avian species. For the latter, the authors wondered whether neuronal satellitosis is expressed in the normal telencephalon of different avian orders and families and whether this pattern in different species shows a specific brain-region association. For these aims, this study explored the presence of neuronal satellitosis in the major areas of the healthy telencephalon in wild and domestic avian species of different orders and families, evaluating its grade in different brain regions. Neuronal satellitosis was seen in the hyperpallium and mesopallium as areas with the highest grade. Passeriformes showed the highest grade of neuronal satellitosis compared to diurnal or nocturnal raptors, and Charadriiformes. To clarify the exact role of neuronal satellitosis in animals without neurological disease, further studies are needed.RESEARCH HIGHLIGHTSNeuronal satellitosis is a common finding in the healthy avian telencephalon.Neuronal satellitosis is a species- and brain-region-associated finding in birds.Passeriformes have the highest grade of neuronal satellitosis.


Assuntos
Aves , Neurônios , Animais , Aves/anatomia & histologia , Neurônios/fisiologia , Telencéfalo/fisiologia
19.
J Morphol ; 283(6): 875-893, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35531925

RESUMO

The avian pelvis plays a critical role in the hindlimb function of birds, connecting the hindlimb and axial skeleton and serving as the major attachment site for proximal hindlimb musculature. To assess how diversification of locomotor modes in birds has impacted the evolution of avian pelvic morphology, we conducted a two-dimensional geometric morphometric analysis of bird pelves in dorsal and lateral views from 163 species (n = 261) across Aves. We investigated the relationships among pelvic shape and ecology, phylogeny, and allometry, and conducted disparity analyses to understand how pelvic morphospace has been explored through the diversification of Aves. We found that while phylogeny was correlated with shape, locomotor categories were significantly discriminated in morphospace in phylogenetically corrected analyses, as was pelvic size. Major shape trends across Aves distinguishing locomotor categories included the relative area of the preacetabular versus postacetabular ilium, how squat or narrow the pelvis is, and the extent of the caudal pelvic border. Birds adapted for hind limb-propelled swimming had particularly distinctive pelves, with narrow, elongated ilia likely useful for holding the hindlimbs close to the body midline and reducing drag. However, ecology and allometry only account for a small proportion of morphological variation, and in general locomotor groups overlapped substantially in morphospace. These results, alongside disparity through time analyses showing widespread convergence in pelvic morphology throughout the Cenozoic, suggest that avian lineages and ecotypes have extensively explored pelvic morphospace, perhaps aided by a loosening of evolutionary constraints following the evolution of forelimb-powered flight.


Assuntos
Aves , Pelve , Animais , Evolução Biológica , Aves/anatomia & histologia , Osso e Ossos , Membro Posterior/anatomia & histologia , Pelve/anatomia & histologia , Filogenia
20.
Zootaxa ; 5124(1): 81-87, 2022 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-35391135

RESUMO

The Short-tailed Albatross Phoebastria albatrus (Pallas, 1769) is a threatened seabird widely distributed in the northern Pacific Ocean with its largest breeding sites on the Senkaku Islands and Torishima Island, Japan, which are separated by over 1700 km. A recent taxonomic revision based on morphological, behavioral, and DNA sequence evidence has revealed that this species consists of two cryptic species: a smaller species which breeds mainly in the Senkaku Islands, and a larger species which breeds mainly on Torishima Island. However, it has remained unclear to which of these species the scientific name Phoebastria albatrus applies, because the type specimens are lost. Here a neotype is designated to resolve this taxonomic issue. From now on, the scientific name Phoebastria albatrus should be applied only to the smaller species breeding on the Senkaku Islands. The name of the larger species is more problematic, as the types of each synonym of P. albatrus must be traced, found, and examined.


Assuntos
Aves , Animais , Aves/anatomia & histologia
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