Potential for Powered Flight Neared by Most Close Avialan Relatives, but Few Crossed Its Thresholds

Current Biology, Год журнала: 2020, Номер 30(20), С. 4033 - 4046.e8

Опубликована: Авг. 6, 2020

Uncertainties in the phylogeny of birds (Avialae) and their closest relatives have impeded deeper understanding early theropod flight. To help address this, we produced an updated evolutionary hypothesis through automated analysis Theropod Working Group (TWiG) coelurosaurian phylogenetic data matrix. Our larger, more resolved, better-evaluated TWiG-based supports grouping dromaeosaurids + troodontids (Deinonychosauria) as sister taxon to (Paraves) recovery Anchiornithinae earliest diverging birds. Although will continue developing, our current results provide a pertinent opportunity evaluate what know about With available for vaned feathered pennaraptorans, estimate potential powered flight among relatives. We did this by using ancestral state reconstruction calculating maximum minimum estimates two proxies potential-wing loading specific lift. These confirm but its rarity ancestors avialan (select unenlagiine microraptorine dromaeosaurids). For first time, find broad range these neared wing lift thresholds indicative potential. This suggests there was greater experimentation with wing-assisted locomotion before evolved than previously appreciated. study adds invaluable support multiple origins theropods (≥3 times), which now from already nearing associated thresholds, provides framework further study. VIDEO ABSTRACT.

Язык: Английский

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Pennaraptoran Theropod Dinosaurs Past Progress and New Frontiers

Bulletin of the American Museum of Natural History, Год журнала: 2020, Номер 440(1), С. 1 - 1

Опубликована: Авг. 21, 2020

Язык: Английский

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Mosaic evolution in an asymmetrically feathered troodontid dinosaur with transitional features

Nature Communications, Год журнала: 2017, Номер 8(1)

Опубликована: Май 2, 2017

Abstract Asymmetrical feathers have been associated with flight capability but are also found in species that do not fly, and their appearance was a major event feather evolution. Among non-avialan theropods, they only known microraptorine dromaeosaurids. Here we report new troodontid, Jianianhualong tengi gen. et sp. nov., from the Lower Cretaceous Jehol Group of China, has anatomical features transitional between long-armed basal troodontids derived short-armed ones, shedding light on troodontid character It indicates feathering is similar to Archaeopteryx having large arm leg as well frond-like tail feathering, confirming these characteristics were widely present among paravians. Most significantly, taxon earliest asymmetrical feathers, suggesting asymmetry ancestral Paraves. This displays mosaic distribution characters like Sinusonasus , another features.

Язык: Английский

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A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight

PeerJ, Год журнала: 2019, Номер 7, С. e7247 - e7247

Опубликована: Июль 10, 2019

The last two decades have seen a remarkable increase in the known diversity of basal avialans and their paravian relatives. lack resolution relationships these groups combined with attributing behavior specialized taxa to base Paraves has clouded interpretations origin avialan flight. Here, we describe Hesperornithoides miessleri gen. et sp. nov., new theropod from Morrison Formation (Late Jurassic) Wyoming, USA, represented by single adult or subadult specimen comprising partial, well-preserved skull postcranial skeleton. Limb proportions firmly establish as occupying terrestrial, non-volant lifestyle. Our phylogenetic analysis emphasizes extensive taxonomic sampling robust character construction, recovering taxon most parsimoniously troodontid close Daliansaurus , Xixiasaurus Sinusonasus . Multiple alternative topologies similar degrees support, but proposals archaeopterygids, microraptorians, Rahonavis being closer Pygostylia than archaeopterygids unenlagiines are strongly rejected. All parsimonious results support hypothesis that each early clade was plesiomorphically flightless, raising possibility avian flight originated late Late Jurassic Early Cretaceous.

Язык: Английский

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The Making of a Flight Feather: Bio-architectural Principles and Adaptation

Cell, Год журнала: 2019, Номер 179(6), С. 1409 - 1423.e17

Опубликована: Ноя. 1, 2019

Язык: Английский

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Paravian Phylogeny and the Dinosaur-Bird Transition: An Overview

Frontiers in Earth Science, Год журнала: 2019, Номер 6

Опубликована: Фев. 12, 2019

Recent years witnessed the discovery of a great diversity early birds as well closely related non-avian theropods, which modified previous conceptions about origin and their flight. We here present review currently taxonomic composition main anatomical characteristics those theropod families with birds, aim to analyze discuss phylogenetic hypotheses that compete some topics dinosaur-bird transition. conclude troodontid affinities anchiornithines, dromaeosaurids microraptorians unenlagiids are dismissed in favor sister group relationships Avialae. After recodification topology TWiG scheme, results on large polytomy at base Pennaraptora. Regarding character evolution, we found that: 1) presence ossified sternum goes hand by uncinate processes; 2) folded forelimbs basal archosaurs indicates widespread distribution among reptiles, contradicting proposals forelimb folding driven propatagial associated tendons was exclusive avian lineage; 3) paravians avialans Archaeopteryx wings relatively wide, short rectricial feathers, rounded alar contour, having convex wing attack margin. These taxa exhibit restricted capabilities forelimbs, preserving hands flexor angles (respect radius/ulna) no lesser than 90º. In more derived instead, rectrices notably elongate angle described between forearm is much less 90º, indicating not only an increased capability but also variety beat movements during Because strong similarities pectoral girdle conformation ratites paravians, it possible infer were similar all these taxa, lacking complex dorsoventral excursion characteristic living neognathans.

Язык: Английский

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Shrinking dinosaurs and the evolution of endothermy in birds

Science Advances, Год журнала: 2020, Номер 6(1)

Опубликована: Янв. 2, 2020

Our heat transfer model suggests that dinosaurs shrank in size as they evolved from cold-blooded reptiles to warm-blooded birds.

Язык: Английский

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The relationship between sternum variation and mode of locomotion in birds

BMC Biology, Год журнала: 2021, Номер 19(1)

Опубликована: Авг. 19, 2021

Abstract Background The origin of powered avian flight was a locomotor innovation that expanded the ecological potential maniraptoran dinosaurs, leading to remarkable variation in modern birds (Neornithes). sternum is anchor for major muscles and, despite varying widely morphology, has not been extensively studied from evolutionary or functional perspectives. We quantify sternal across broad phylogenetic scope using 3D geometric morphometrics methods. Using this comprehensive dataset, we apply phylogenetically informed regression approaches test hypotheses size allometry and correlation shape with both locomotory capabilities, including flightlessness highly swimming styles Neornithes. Results find evidence isometry relative body mass document significant alongside important correlations capability, reflecting effects musculoskeletal variation. Among these, show large deep cranially projected keel necessary birds, deeper keels are correlated slower but stronger flight, robust caudal borders associated faster flapping styles, narrower sterna running abilities. Correlations between locomotion weak explanatory power, indicating although broadly ecology, other unexplored factors also important. Conclusions These results display importance by providing novel understanding form function Our study lays groundwork estimating abilities paravian ancestors Neornithes, highlighting critical element will be useful future work on along dinosaur-bird lineage.

Язык: Английский

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Exceptional preservation and foot structure reveal ecological transitions and lifestyles of early theropod flyers

Nature Communications, Год журнала: 2022, Номер 13(1)

Опубликована: Дек. 20, 2022

Abstract Morphology of keratinised toe pads and foot scales, hinging joints claw shape size all inform the grasping ability, cursoriality feeding mode living birds. Presented here is morphological evidence from fossil feet early theropod flyers. Foot soft tissues joint articulations are qualitatively assessed using laser-stimulated fluorescence. Pedal quantitatively analysed traditional morphometrics. We interpret these data among existing to better understand evolutionary ecology Jurassic flyers like Anchiornis Archaeopteryx show adaptations suggestive relatively ground-dwelling lifestyles. Early Cretaceous then diversify into more aerial lifestyles, including generalists Confuciusornis specialists climbing Fortunguavis . Some birds, Late Berlin Sapeornis , complex ecologies seemingly unique sampled modern As a non-bird flyer, finding affinities Microraptor specialised raptorial lifestyle unexpected. Its hawk-like characteristics rare known time suggesting that some perform roles filled by birds today. demonstrate diverse ecological profiles flyers, changing as flight developed, have roles.

Язык: Английский

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Spectral-Kurtosis and Image-Embedding Approach for Target Classification in Micro-Doppler Signatures

Electronics, Год журнала: 2024, Номер 13(2), С. 376 - 376

Опубликована: Янв. 16, 2024

Micro-Doppler signature represents the micromotion state of a target, and it is used in target recognition classification technology. The micro-Doppler frequency appears as transition Doppler due to rotation vibration an object. Thus, tracking classifying targets with high accuracy possible. However, difficult distinguish types when subdividing same or different similar velocities. In this study, we address problem three speeds segmentation type targets. A novel extraction procedure developed automatically recognize drone, bird, human by exploiting signatures exhibited each target. algorithm based on adaptation spectral kurtosis technique radar echoes reflected types. Further, image-embedding layers are classify objects micromotion. We apply ResNet34 deep neural network images analyze its performance performing micro-movements collected bistatic data. results demonstrate that proposed method accurately differentiates effectively classifies multiple

Язык: Английский

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