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  • 1
    Language: English
    In: Journal of anatomy, 2016-11, Vol.229 (5), p.631-656
    Description: Mechanisms for passively coordinating forelimb movements and flight feather abduction and adduction have been described separately from both in vivo and ex vivo studies. Skeletal coordination has been identified as a way for birds to simplify the neuromotor task of controlling flight stroke, but an understanding of the relationship between skeletal coordination and the coordination of the aerodynamic control surface (the flight feathers) has been slow to materialize. This break between the biomechanical and aerodynamic approaches – between skeletal kinematics and airfoil shape – has hindered the study of dynamic flight behaviors. Here I use dissection and histology to identify previously overlooked interconnections between musculoskeletal elements and flight feathers. Many of these structures are well‐placed to directly link elements of the passive musculoskeletal coordination system with flight feather movements. Small bundles of smooth muscle form prominent connections between upper forearm coverts (deck feathers) and the ulna, as well as the majority of interconnections between major flight feathers of the hand. Abundant smooth muscle may play a role in efficient maintenance of folded wing posture, and may also provide an autonomically regulated means of tuning wing shape and aeroelastic behavior in flight. The pattern of muscular and ligamentous linkages of flight feathers to underlying muscle and bone may provide predictable passive guidance for the shape of the airfoil during flight stroke. The structures described here provide an anatomical touchstone for in vivo experimental tests of wing surface coordination in an extensively researched avian model species.
    Subject(s): Animals ; avian ; Bone and Bones - anatomy & histology ; Columbidae - anatomy & histology ; covert feathers ; Feathers - anatomy & histology ; flight feathers ; Flight, Animal - physiology ; Muscle, Smooth - anatomy & histology ; Original ; Pigeons ; quill knobs ; Smooth muscle ; wing shape ; Wings, Animal - anatomy & histology ; X-Ray Microtomography
    ISSN: 0021-8782
    E-ISSN: 1469-7580
    Source: Hellenic Academic Libraries Link
    Source: PubMed Central
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  • 2
    Language: English
    In: BMC ecology and evolution, 2019-01-05, Vol.19 (1), p.3-3
    Description: BackgroundThe lake deposits of the informal Ruby Paper Shale unit, part of the Renova Formation of Montana, have yielded abundant plant fossils that document Late Eocene - Early Oligocene global cooling in western North America. A nearly complete small bird with feather impressions was recovered from this unit in in 1959, but has only been informally mentioned.ResultsHere we describe this fossil and identify it as a new species of Zygodactylus, a stem lineage passerine with a zygodactyl foot. The new taxon shows morphological traits that are convergent on crown Passeriformes, including an elongate hallux, reduced body size, and a comparative shortening of proximal limb elements. The fossil documents the persistence of this lineage into the earliest Oligocene (similar to 33Ma) in North America. It is the latest occurring North American species of a group that persists in Europe until the Miocene.ConclusionsEocene-Oligocene global cooling is known to have significantly remodeled both Palearctic and Nearctic mammal faunas but its impact on related avifaunas has remained poorly understood. The geographic and temporal range expansion provided by the new taxon together with avian other taxa with limited fossil records suggests a similar pattern of retraction in North America followed by Europe.
    Subject(s): Animals ; Birds ; Body Size ; Cooling ; Creeks & streams ; Eocene ; Evolutionary Biology ; Extremities - anatomy & histology ; Feathers - anatomy & histology ; Fossils ; Genetics & Heredity ; Geography ; Global cooling ; Life Sciences & Biomedicine ; Miocene ; Museums ; New records ; New species ; North America ; Oligocene ; Paleobiogeography ; Paleogene ; Paleontology ; Passeriformes ; Passeriformes - classification ; Phylogenetics ; Phylogeny ; Piciformes ; Plant fossils ; Range extension ; Science & Technology ; Shale ; Skull - anatomy & histology ; Species Specificity ; Spine - anatomy & histology ; Taxa ; Time Factors ; Zygodactylidae
    ISSN: 1471-2148
    E-ISSN: 1471-2148
    E-ISSN: 2730-7182
    Source: BioMedCentral Open Access
    Source: Academic Search Ultimate
    Source: Web of Science - Science Citation Index Expanded - 2019〈img src="http://exlibris-pub.s3.amazonaws.com/fromwos-v2.jpg" /〉
    Source: PubMed Central
    Source: DOAJ Directory of Open Access Journals - Not for CDI Discovery
    Source: ProQuest Central
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  • 3
    Language: English
    In: Nature (London), 2013-05-30, Vol.497 (7451), p.611-614
    Description: Apes and Old World monkeys are prominent components of modern African and Asian ecosystems, yet the earliest phases of their evolutionary history have remained largely undocumented. The absence of crown catarrhine fossils older than ∼20 million years (Myr) has stood in stark contrast to molecular divergence estimates of ∼25-30 Myr for the split between Cercopithecoidea (Old World monkeys) and Hominoidea (apes), implying long ghost lineages for both clades. Here we describe the oldest known fossil 'ape', represented by a partial mandible preserving dental features that place it with 'nyanzapithecine' stem hominoids. Additionally, we report the oldest stem member of the Old World monkey clade, represented by a lower third molar. Both specimens were recovered from a precisely dated 25.2-Myr-old stratum in the Rukwa Rift, a segment of the western branch of the East African Rift in Tanzania. These finds extend the fossil record of apes and Old World monkeys well into the Oligocene epoch of Africa, suggesting a possible link between diversification of crown catarrhines and changes in the African landscape brought about by previously unrecognized tectonic activity in the East African rift system.
    Subject(s): Animals ; Apes ; Cercopithecidae - anatomy & histology ; Cercopithecidae - classification ; Divergent evolution ; Fossils ; History, Ancient ; Hominidae - anatomy & histology ; Hominidae - classification ; Mandible - anatomy & histology ; Natural history ; Observations ; Old-World monkeys ; Paleontology ; Phylogeny ; Tanzania ; Tooth - anatomy & histology
    ISSN: 0028-0836
    E-ISSN: 1476-4687
    Source: Academic Search Ultimate
    Source: Get It Now
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  • 4
    Language: English
    In: Journal of anatomy, 2017-04, Vol.230 (4), p.549-566
    Description: In utero, baleen whales initiate the development of several dozens of teeth in upper and lower jaws. These tooth germs reach the bell stage and are sometimes mineralized, but toward the end of prenatal life they are resorbed and no trace remains after birth. Around the time that the germs disappear, the keratinous baleen plates start to form in the upper jaw, and these form the food‐collecting mechanism. Baleen whale ancestors had two generations of teeth and never developed baleen, and the prenatal teeth of modern fetuses are usually interpreted as an evolutionary leftover. We investigated the development of teeth and baleen in bowhead whale fetuses using histological and immunohistochemical evidence. We found that upper and lower dentition initially follow similar developmental pathways. As development proceeds, upper and lower tooth germs diverge developmentally. Lower tooth germs differ along the length of the jaw, reminiscent of a heterodont dentition of cetacean ancestors, and lingual processes of the dental lamina represent initiation of tooth bud formation of replacement teeth. Upper tooth germs remain homodont and there is no evidence of a secondary dentition. After these germs disappear, the oral epithelium thickens to form the baleen plates, and the protein FGF‐4 displays a signaling pattern reminiscent of baleen plates. In laboratory mammals, FGF‐4 is not involved in the formation of hair or palatal rugae, but it is involved in tooth development. This leads us to propose that the signaling cascade that forms teeth in most mammals has been exapted to be involved in baleen plate ontogeny in mysticetes.
    Subject(s): Animals ; Balaena mysticetus ; baleen ; baleen whales ; Biological Evolution ; bowhead whale ; Bowhead Whale - anatomy & histology ; Bowhead Whale - embryology ; Cetacea ; Dentition, Mixed ; embryology ; Female ; Fetuses ; FGF ; Jaw - anatomy & histology ; Jaw - embryology ; Keratin ; Mouth - anatomy & histology ; Mouth - embryology ; Mysticetes ; ontogeny ; Original ; Pregnancy ; Teeth ; Tooth - anatomy & histology ; Tooth - embryology ; tooth development ; Whales & whaling
    ISSN: 0021-8782
    E-ISSN: 1469-7580
    Source: Hellenic Academic Libraries Link
    Source: PubMed Central
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  • 5
    Language: English
    In: BMC evolutionary biology, 2015-02-27, Vol.15 (1), p.30-30
    Description: Among living fliers (birds, bats, and insects), birds display relatively high aspect ratios, a dimensionless shape variable that distinguishes long and narrow vs. short and broad wings. Increasing aspect ratio results in a functional tradeoff between low induced drag (efficient cruise) and increased wing inertia (difficult takeoff). Given the wide scope of its functional effects, the pattern of aspect ratio evolution is an important factor that contributes to the substantial ecological and phylogenetic diversity of living birds. However, because the feathers that define the wingtip (and hence wingspan and aspect ratio) often do not fossilize, resolution in the pattern of avian wing shape evolution is obscured by missing information. Here I use a comparative approach to investigate the relationship between skeletal proxies of flight feather attachment and wing shape. An accessory lobe of the internal index process of digit II-1, a bony correlate of distal primary attachment, shows weak but statistically significant relationships to aspect ratio and mass independent of other skeletal morphology. The dorsal phalangeal fossae of digit II-1, which house distal primaries VIII and IX, also show a trend of increased prominence with higher aspect ratio. Quill knobs on the ulna are examined concurrently, but do not show consistent signal with respect to wing shape. Although quill knobs are cited as skeletal correlates of flight performance in birds, their relationship to wing shape is inconsistent among extant taxa, and may reflect diverging selection pressures acting on a conserved architecture. In contrast, correlates of distal primary feather attachment on the major digit show convergent responses to increasing aspect ratio. In light of the diversity of musculoskeletal and integumentary mophology that underlies wing shape in different avian clades, it is unlikely that a single skeletal feature will show consistent predictive power across Neoaves. Confident inference of wing shape in basal ornithurine birds will require multiple lines of evidence, together with an understanding of clade-specific evolutionary trends within the crown.
    Subject(s): Animals ; Aves ; Biological Evolution ; Birds - anatomy & histology ; Birds - classification ; Birds - physiology ; Bone and Bones - anatomy & histology ; Feather ; Feathers ; Flight, Animal ; Forelimb evolution ; Fossils ; Osteology ; Phylogenetic comparative methods ; Phylogeny ; Quill knobs ; Wings, Animal - anatomy & histology ; Wings, Animal - physiology
    ISSN: 1471-2148
    E-ISSN: 1471-2148
    Source: BioMedCentral Open Access
    Source: Academic Search Ultimate
    Source: PubMed Central
    Source: DOAJ Directory of Open Access Journals - Not for CDI Discovery
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  • 6
    Language: English
    In: Developmental dynamics, 2015-10, Vol.244 (10), p.1184-1192
    Description: The field of evolutionary developmental biology is broadly focused on identifying the genetic and developmental mechanisms underlying morphological diversity. Connecting the genotype with the phenotype means that evo‐devo research often considers a wide range of evidence, from genetics and morphology to fossils. In this commentary, we provide an overview and framework for integrating fossil ontogenetic data with developmental data using phylogenetic comparative methods to test macroevolutionary hypotheses. We survey the vertebrate fossil record of preserved embryos and discuss how phylogenetic comparative methods can integrate data from developmental genetics and paleontology. Fossil embryos provide limited, yet critical, developmental data from deep time. They help constrain when developmental innovations first appeared during the history of life and also reveal the order in which related morphologies evolved. Phylogenetic comparative methods provide a powerful statistical approach that allows evo‐devo researchers to infer the presence of nonpreserved developmental traits in fossil species and to detect discordant evolutionary patterns and processes across levels of biological organization. Developmental Dynamics 244:1184–1192, 2015. © 2015 Wiley Periodicals, Inc. Key Findings Fossil embryos help constrain when developmental innovations first appeared. Fossil embryos help reveal the order in which related morphologies evolved. Phylogenetic comparative methods can link fossil data to developmental and genetic data of extant species. Non‐preserved developmental traits in fossil species can be inferred with phylogenetic comparative methods. Discordant evolutionary patterns and processes across levels of biological organization can be detected with phylogenetic comparative methods.
    Subject(s): Animals ; Developmental biology ; Developmental Biology - methods ; Embryo, Nonmammalian ; Embryonic development ; embryos ; evolutionary developmental biology ; Fossils ; macroevolution ; Models, Statistical ; Paleontology ; phylogenetic comparative methods ; Phylogeny ; Vertebrates
    ISSN: 1058-8388
    E-ISSN: 1097-0177
    Source: Elektronische Zeitschriftenbibliothek - Frei zugängliche E-Journals
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  • 7
    Language: English
    In: American journal of physical anthropology, 2019-12, Vol.170 (4), p.565-578
    Description: Objectives Primate diagonal sequence (DS) gaits are often argued to be an adaptation for moving and foraging in the fine‐branch niche; however, existing data have come predominantly from laboratory studies that are limited in taxonomic breadth and fail to account for the structural and ecological variation of natural substrates. We test the extent to which substrate diameter and orientation influence gait sequence type and limb phase in free‐ranging primates, as well as how phylogenetic relatedness might condition response patterns. Materials and methods We filmed quadrupedal locomotion in 11 platyrrhine species at field sites in Ecuador and Costa Rica and measured the diameter and orientation of locomotor substrates using remote sensors. We quantified limb phase values and classified strides by gait sequence type (N = 988 strides). Results Our results show that most of the species in our sample consistently used DS gaits, regardless of substrate diameter or orientation; however, all taxa also used asymmetrical and/or lateral sequence gaits. By incorporating phylogenetic eigenvectors into our models, we found significant differences in gait sequence patterns and limb phase values among the major platyrrhine clades, suggesting that phylogeny may be a better predictor of gait than substrate diameter or orientation. Discussion Our field data generally corroborate locomotor patterns from laboratory studies but capture additional aspects of gait variability and flexibility in response to the complexity of natural environments. Overall, our results suggest that DS gaits are not exclusively tailored to narrow or oblique substrates but are used on arboreal substrates in general.
    Subject(s): Anthropology ; arboreal quadrupedalism ; Evolution ; Evolutionary Biology ; Flexibility ; Gait ; Laboratories ; Life Sciences & Biomedicine ; Locomotion ; phylogenetic eigenvector ; Phylogenetics ; Phylogeny ; platyrrhine ; Primates ; Relatedness ; Science & Technology ; Substrates ; Variability
    ISSN: 0002-9483
    E-ISSN: 1096-8644
    Source: International Bibliography of the Social Sciences (IBSS)
    Source: Hellenic Academic Libraries Link
    Source: Web of Science - Science Citation Index Expanded - 2019〈img src="http://exlibris-pub.s3.amazonaws.com/fromwos-v2.jpg" /〉
    Source: Web of Science - Social Sciences Citation Index – 2019〈img src="http://exlibris-pub.s3.amazonaws.com/fromwos-v2.jpg" /〉
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  • 8
    Language: English
    In: Anatomical record (Hoboken, N.J. : 2007), 2022-02, Vol.305 (2), p.462-476
    Description: Bats are the only mammals to have achieved powered flight. A key innovation allowing for bats to conquer the skies was a forelimb modified into a flexible wing. The wing bones of bats are exceptionally long and dynamically bend with wingbeats. Bone microarchitectural features supporting these novel performance attributes are still largely unknown. The humeri and femora of bats are typically avascular, except for large‐bodied taxa (e.g., pteropodid flying foxes). No thorough investigation of vascular canal regionalization and morphology has been undertaken as historically it has been difficult to reconstruct the 3D architecture of these canals. This study augments our understanding of the vascular networks supporting the bone matrix of a sample of bats (n = 24) of variable body mass, representing three families (Pteropodidae [large‐bodied, species = 6], Phyllostomidae [medium‐bodied, species = 2], and Molossidae [medium‐bodied, species = 1]). We employed Synchrotron Radiation‐based micro‐Computed Tomography (SRμCT) to allow for a detailed comparison of canal morphology within humeri and femora. Results indicate that across selected bats, canal number per unit volume is similar independent of body size. Differences in canal morphometry based on body size and bone type appear primarily related to a broader distribution of the canal network as cortical volume increases. Heavier bats display a relatively rich vascular network of mostly longitudinally‐oriented canals that are localized mainly to the mid‐cortical and endosteal bone envelopes. Taken together, our results suggest that relative vascularity of the limb bones of heavier bats forms support for nutrient exchange in a regional pattern.
    Subject(s): Analysis ; Animals ; Bats ; Body mass ; Body size ; bone ; Bone (cortical) ; Bone and Bones ; Bone matrix ; Bones ; Canals (anatomy) ; Chiroptera ; Computed tomography ; cortical porosity ; CT imaging ; Extremities ; Flight, Animal ; Humans ; micro‐CT ; Morphology ; Morphometry ; Porosity ; Species ; synchrotron ; Wings, Animal ; X-Ray Microtomography
    ISSN: 1932-8486
    E-ISSN: 1932-8494
    Source: Alma/SFX Local Collection
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  • 9
    Language: English
    In: Nature (London), 2010-08-05, Vol.466 (7307), p.748-751
    Description: Fossil crocodyliforms discovered in recent years have revealed a level of morphological and ecological diversity not exhibited by extant members of the group. This diversity is particularly notable among taxa of the Cretaceous Period (144-65 million years ago) recovered from former Gondwanan landmasses. Here we report the discovery of a new species of Cretaceous notosuchian crocodyliform from the Rukwa Rift Basin of southwestern Tanzania. This small-bodied form deviates significantly from more typical crocodyliform craniodental morphologies, having a short, broad skull, robust lower jaw, and a dentition with relatively few teeth that nonetheless show marked heterodonty. The presence of morphologically complex, complementary upper and lower molariform teeth suggests a degree of crown-crown contact during jaw adduction that is unmatched among known crocodyliforms, paralleling the level of occlusal complexity seen in mammals and their extinct relatives. The presence of another small-bodied mammal-like crocodyliform in the Cretaceous of Gondwana indicates that notosuchians probably filled niches and inhabited ecomorphospace that were otherwise occupied by mammals on northern continents.
    Subject(s): Animals ; Biological Evolution ; Crocodilia ; Dentition ; Earth sciences ; Earth, ocean, space ; Exact sciences and technology ; Fossils ; History, Ancient ; Mammals - anatomy & histology ; Mammals - classification ; Mammals - physiology ; Natural history ; Paleontology ; Phylogeny ; Tanzania ; Tomography, X-Ray Computed ; Vertebrate paleontology
    ISSN: 0028-0836
    E-ISSN: 1476-4687
    Source: Academic Search Ultimate
    Source: Get It Now
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  • 10
    Language: English
    In: PeerJ (San Francisco, CA), 2016, Vol.4, p.e1696-e1696
    Description: Nearly all living artiodactyls (even-toed ungulates) possess a derived cranial arterial pattern that is highly distinctive from most other mammals. Foremost among a suite of atypical arterial configurations is the functional and anatomical replacement of the internal carotid artery with an extensive, subdural arterial meshwork called the carotid rete. This interdigitating network branches from the maxillary artery and is housed within the cavernous venous sinus. As the cavernous sinus receives cooled blood draining from the nasal mucosa, heat rapidly dissipates across the high surface area of the rete to be carried away from the brain by the venous system. This combination yields one of the most effective mechanisms of selective brain cooling. Although arterial development begins from the same embryonic scaffolding typical of mammals, possession of a rete is typically accompanied by obliteration of the internal carotid artery. Among taxa with available ontogenetic data, the point at which the internal carotid obliterates is variable throughout development. In small-bodied artiodactyls, the internal carotid typically obliterates prior to parturition, but in larger species, the vessel may remain patent for several years. In this study, we use digital anatomical data collection methods to describe the cranial arterial patterns for a growth series of giraffe (Giraffa camelopardalis), from parturition to senescence. Giraffes, in particular, have unique cardiovascular demands and adaptations owing to their exceptional body form and may not adhere to previously documented stages of cranial arterial development. We find the carotid arterial system to be conserved between developmental stages and that obliteration of the giraffe internal carotid artery occurs prior to parturition.
    Subject(s): Adaptations ; Anatomical imaging ; Arterial development ; Artiodactyla ; Biology ; Blood pressure ; Carotid arteries ; Carotid artery ; Carotid rete ; CT scan ; Developmental Biology ; Developmental stages ; Embryogenesis ; Evolutionary Studies ; Giraffa camelopardalis ; Giraffidae ; Health sciences ; Mammalia ; Maxilla ; Mucosa ; Neurosciences ; Ontogeny ; Parturition ; Physiology ; Ruminant ; Senescence ; Sinus ; Skull ; Ungulates ; Veins & arteries ; Zoology
    ISSN: 2167-8359
    E-ISSN: 2167-8359
    Source: PubMed Central
    Source: DOAJ Directory of Open Access Journals - Not for CDI Discovery
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