1
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Pritchard AC, Irmis RB, Olori JC, Nesbitt SJ, Smith ND, Stocker MR, Turner AH. The femora of Drepanosauromorpha (Reptilia: Diapsida): Implications for the functional evolution of the thigh of Sauropsida. Anat Rec (Hoboken) 2023. [PMID: 36847780 DOI: 10.1002/ar.25160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/29/2022] [Accepted: 12/30/2022] [Indexed: 03/01/2023]
Abstract
The femora of diapsids have undergone morphological changes related to shifts in postural and locomotor modes, such as the transition from plesiomorphic amniote and diapsid taxa to the apomorphic conditions related to a more erect posture within Archosauriformes. One remarkable clade of Triassic diapsids is the chameleon-like Drepanosauromorpha. This group is known from numerous articulated but heavily compressed skeletons that have the potential to further inform early reptile femoral evolution. For the first time, we describe the three-dimensional osteology of the femora of Drepanosauromorpha, based on undistorted fossils from the Upper Triassic Chinle Formation and Dockum Group of North America. We identify apomorphies and a combination of character states that link these femora to those in crushed specimens of drepanosauromorphs and compare our sample with a range of amniote taxa. Several characteristics of drepanosauromorph femora, including a hemispherical proximal articular surface, prominent asymmetry in the proximodistal length of the tibial condyles, and a deep intercondylar sulcus, are plesiomorphies shared with early diapsids. The femora contrast with those of most diapsids in lacking a crest-like, distally tapering internal trochanter. They bear a ventrolaterally positioned tuberosity on the femoral shaft, resembling the fourth trochanter in Archosauriformes. The reduction of an internal trochanter parallels independent reductions in therapsids and archosauriforms. The presence of a ventrolaterally positioned trochanter is also similar to that of chameleonid squamates. Collectively, these features demonstrate a unique femoral morphology for drepanosauromorphs, and suggest an increased capacity for femoral adduction and protraction relative to most other Permo-Triassic diapsids.
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Affiliation(s)
| | - Randall B Irmis
- Natural History Museum of Utah and Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah, USA
| | | | - Sterling J Nesbitt
- Virginia Museum of Natural History, Martinsville, Virginia, USA.,Virginia Tech, Blacksburg, Virginia, USA
| | - Nathan D Smith
- Natural History Museum of Los Angeles County, Los Angeles, California, USA
| | - Michelle R Stocker
- Virginia Museum of Natural History, Martinsville, Virginia, USA.,Virginia Tech, Blacksburg, Virginia, USA
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2
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Mongle CS, Nesbitt A, Machado FA, Smaers JB, Turner AH, Grine FE, Uyeda JC. A common mechanism drives the alignment between the micro- and macroevolution of primate molars. Evolution 2022; 76:2975-2985. [PMID: 36005286 DOI: 10.1111/evo.14600] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 07/25/2022] [Accepted: 08/01/2022] [Indexed: 01/22/2023]
Abstract
A central challenge for biology is to reveal how different levels of biological variation interact and shape diversity. However, recent experimental studies have indicated that prevailing models of evolution cannot readily explain the link between micro- and macroevolution at deep timescales. Here, we suggest that this paradox could be the result of a common mechanism driving a correlated pattern of evolution. We examine the proportionality between genetic variance and patterns of trait evolution in a system whose developmental processes are well understood to gain insight into how such alignment between morphological divergence and genetic variation might be maintained over macroevolutionary time. Primate molars present a model system by which to link developmental processes to evolutionary dynamics because of the biased pattern of variation that results from the developmental architecture regulating their formation. We consider how this biased variation is expressed at the population level, and how it manifests through evolution across primates. There is a strong correspondence between the macroevolutionary rates of primate molar divergence and their genetic variation. This suggests a model of evolution in which selection is closely aligned with the direction of genetic variance, phenotypic variance, and the underlying developmental architecture of anatomical traits.
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Affiliation(s)
- Carrie S Mongle
- Department of Anthropology, Stony Brook University, Stony Brook, New York, 11794.,Division of Anthropology, American Museum of Natural History, New York, New York, 10024.,Turkana Basin Institute, Stony Brook University, Stony Brook, New York, 11794
| | - Allison Nesbitt
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, Missouri, 65212
| | - Fabio A Machado
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, 24061
| | - Jeroen B Smaers
- Department of Anthropology, Stony Brook University, Stony Brook, New York, 11794
| | - Alan H Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York, 11794
| | - Frederick E Grine
- Department of Anthropology, Stony Brook University, Stony Brook, New York, 11794.,Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York, 11794
| | - Josef C Uyeda
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, 24061
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3
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Napoli JG, Ruebenstahl AA, Bhullar BAS, Turner AH, Norell MA. A New Dromaeosaurid (Dinosauria: Coelurosauria) from Khulsan, Central Mongolia. American Museum Novitates 2021. [DOI: 10.1206/3982.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- James G. Napoli
- Richard Gilder Graduate School, American Museum of Natural History, New York
| | | | | | - Alan H. Turner
- Division of Paleontology, American Museum of Natural History, New York
| | - Mark A. Norell
- Richard Gilder Graduate School, American Museum of Natural History, New York
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4
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Melstrom KM, Turner AH, Irmis RB. Reevaluation of the cranial osteology and phylogenetic position of the early crocodyliform Eopneumatosuchus colberti, with an emphasis on its endocranial anatomy. Anat Rec (Hoboken) 2021; 305:2557-2582. [PMID: 34679248 DOI: 10.1002/ar.24777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 07/30/2021] [Accepted: 08/09/2021] [Indexed: 01/21/2023]
Abstract
Eopneumatosuchus colberti Crompton and Smith, 1980, known from a single partial skull, is an enigmatic crocodylomorph from the Lower Jurassic Kayenta Formation. In spite of its unique morphology, an exceptionally pneumatic braincase, and presence during a critical time period of crocodylomorph evolution, relatively little is known about this taxon. Here, we redescribe the external cranial morphology of E. colberti, present novel information on its endocranial anatomy, evaluate its phylogenetic position among early crocodylomorphs, and seek to better characterize its ecology. Our examination clarifies key aspects of cranial suture paths and braincase anatomy. Comparisons with related taxa (e.g., Protosuchus haughtoni) demonstrate that extreme pneumaticity of the braincase may be more widespread in protosuchids than previously appreciated. Computed tomography scans reveal an endocranial morphology that resembles that of other early crocodylomorphs, in particular the noncrocodyliform crocodylomorph Almadasuchus figarii. There are, however, key differences in olfactory bulb and cerebral hemisphere morphology, which demonstrate the endocranium of crocodylomorphs is not as conserved as previously hypothesized. Our phylogenetic analysis recovers E. colberti as a close relative of Protosuchus richardsoni and Edentosuchus tienshanensis, contrasting with previous hypotheses of a sister group relationship with Thalattosuchia. Previous work suggested the inner ear has some similarities to semi-aquatic crocodyliforms, but the phylogenetic placement of E. colberti among protosuchids with a terrestrial postcranial skeletal morphology complicates paleoecological interpretation.
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Affiliation(s)
- Keegan M Melstrom
- Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, California, USA
| | - Alan H Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York, USA
| | - Randall B Irmis
- Natural History Museum of Utah, University of Utah, Salt Lake City, Utah, USA.,Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah, USA
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5
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Wilberg EW, Beyl AR, Pierce SE, Turner AH. Cranial and endocranial anatomy of a three-dimensionally preserved teleosauroid thalattosuchian skull. Anat Rec (Hoboken) 2021; 305:2620-2653. [PMID: 34259385 DOI: 10.1002/ar.24704] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/14/2021] [Accepted: 06/02/2021] [Indexed: 01/14/2023]
Abstract
Thalattosuchians represent one of the several independent transitions into the marine realm among crocodylomorphs. The extent of their aquatic adaptations ranges from the semiaquatic teleosauroids, superficially resembling extant gharials, to the almost cetacean-like pelagic metriorhynchids. Understanding the suite of osteological, physiological, and sensory changes that accompanied this major transition has received increased attention, but is somewhat hindered by a dearth of complete three-dimensionally preserved crania. Here, we describe the cranial and endocranial anatomy of a well-preserved three-dimensional specimen of Macrospondylus bollensis from the Toarcian of Yorkshire, UK. The trigeminal fossa contains two similar-sized openings separated by a thin lamina of prootic, a configuration that appears unique to a subset of teleosauroids. Macrospondylus bollensis resembles other thalattosuchians in having pyramidal semicircular canals with elongate cochlear ducts, enlarged carotid canals leading to an enlarged pituitary fossa, enlarged orbital arteries, enlarged endocranial venous sinuses, reduced pharyngotympanic sinuses, and a relatively straight brain with a hemispherical cerebral expansion. We describe for the first time the olfactory region and paranasal sinuses of a teleosauroid. A relatively large olfactory region suggests greater capacity for airborne olfaction in teleosauroids than in the more aquatically adapted metriorhynchoids. Additionally, slight swellings in the olfactory region suggest the presence of small salt glands of lower secretory capacity than those of metriorhynchoids. The presence of osteological correlates for salt glands in a teleosauroid corroborates previous hypotheses that these glands originated in the common ancestor of Thalattosuchia, facilitating their rapid radiation into the marine realm.
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Affiliation(s)
- Eric W Wilberg
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York, USA
| | - Alexander R Beyl
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York, USA
| | - Stephanie E Pierce
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Alan H Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York, USA
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6
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Erb A, Turner AH. Braincase anatomy of the Paleocene crocodyliform Rhabdognathus revealed through high resolution computed tomography. PeerJ 2021; 9:e11253. [PMID: 33986990 PMCID: PMC8103917 DOI: 10.7717/peerj.11253] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 03/20/2021] [Indexed: 11/20/2022] Open
Abstract
Dyrosaurids were highly specialized, largely marine, relatives of living crocodylians, and one of the few archosaur lineages to survive the K-Pg extinction. Dyrosaurids lived during the Cretaceous to the Eocene and represent a unique combination of morphology and ecology not seen in living crocodylians. Little is known about their endocranial anatomy, leaving many questions about their neurosensory adaptations unaddressed. Recently, µCT (micro-computed tomography) scans were made of a well-preserved skull of Rhabdognathus, a Paleocene dyrosaurid from Mali. This marks the first time the braincase and neurosensory features of a dyrosaurid have been examined using CT. We focus our attention to three specific internal structures: the cranial endocast; the inner ear; and the paratympanic sinuses. The cranial endocast of Rhabdognathus revealed novel features including a unique conformation of its paratympanic system, a prominent dorsal venous system that communicates with the external skull table, extremely enlarged tympanic vestibules that meet at the midline of the endocranium, a prominent spherical cerebrum, and elongate olfactory tracts accounting for half the total endocast length. The bizarre laterally facing lateral Eustachian foramen of dyrosaurids is now understood to be a complex fossa including both a ventrally directed lateral Eustachian foramen and a laterally directed foramen for the basioccipital diverticulum. A novel median pterygopharyngeal canal was discovered connecting the pharynx to the adductor chamber. These revelations require a reinterpretation of the associated external foramina visible on the posterior of the skull in dyrosaurids and potentially their close relatives the pholidosaurids. The olfactory tract terminates in an enlarged olfactory region possessing complex bony projections—a unique morphology perhaps serving to increase surface area for olfaction. The inner ear of Rhabdognathus exhibits characteristics seen in both Pelagosaurus and Gavialis. The vestibule is spherical, as in Gavialis, but is significantly expanded. The semicircular canals are enlarged but pyramidal in shape as in the thalattosuchian Pelagosaurus. The proportion of the cochlear length to total endosseous labyrinth height is roughly 0.5 in Rhabdognathus implying that the hearing capabilities resemble that of thalattosuchians. A suite of expanded sense organs (e.g., bony olfactory lamina; hypertrophied vestibule of the inner ear), and the clear expansion of the cerebrum to a more symmetrical and spherical shape suggest that dyrosaurids possess neuroanatomical modifications facilitating an agile predatory near-shore ecology.
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Affiliation(s)
- Arthur Erb
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, United States of America
| | - Alan H Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, United States of America
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7
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Turner AH, Montanari S, Norell MA. A New Dromaeosaurid from the Late Cretaceous Khulsan Locality of Mongolia. American Museum Novitates 2021. [DOI: 10.1206/3965.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Alan H. Turner
- Division of Paleontology, American Museum of Natural History, New York, and Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York
| | - Shaena Montanari
- Division of Paleontology, American Museum of Natural History, New York; currently Walter Cronkite School of Journalism and Mass Communication at Arizona State University, Phoenix Arizona
| | - Mark A. Norell
- Division of Paleontology, American Museum of Natural History, New York
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8
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Ezcurra MD, Nesbitt SJ, Bronzati M, Dalla Vecchia FM, Agnolin FL, Benson RBJ, Brissón Egli F, Cabreira SF, Evers SW, Gentil AR, Irmis RB, Martinelli AG, Novas FE, Roberto da Silva L, Smith ND, Stocker MR, Turner AH, Langer MC. Enigmatic dinosaur precursors bridge the gap to the origin of Pterosauria. Nature 2020; 588:445-449. [DOI: 10.1038/s41586-020-3011-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/25/2020] [Indexed: 11/09/2022]
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9
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O'Connor PM, Turner AH, Groenke JR, Felice RN, Rogers RR, Krause DW, Rahantarisoa LJ. Late Cretaceous bird from Madagascar reveals unique development of beaks. Nature 2020; 588:272-276. [PMID: 33239782 DOI: 10.1038/s41586-020-2945-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 09/14/2020] [Indexed: 11/09/2022]
Abstract
Mesozoic birds display considerable diversity in size, flight adaptations and feather organization1-4, but exhibit relatively conserved patterns of beak shape and development5-7. Although Neornithine (that is, crown group) birds also exhibit constraint on facial development8,9, they have comparatively diverse beak morphologies associated with a range of feeding and behavioural ecologies, in contrast to Mesozoic birds. Here we describe a crow-sized stem bird, Falcatakely forsterae gen. et sp. nov., from the Late Cretaceous epoch of Madagascar that possesses a long and deep rostrum, an expression of beak morphology that was previously unknown among Mesozoic birds and is superficially similar to that of a variety of crown-group birds (for example, toucans). The rostrum of Falcatakely is composed of an expansive edentulous maxilla and a small tooth-bearing premaxilla. Morphometric analyses of individual bony elements and three-dimensional rostrum shape reveal the development of a neornithine-like facial anatomy despite the retention of a maxilla-premaxilla organization that is similar to that of nonavialan theropods. The patterning and increased height of the rostrum in Falcatakely reveals a degree of developmental lability and increased morphological disparity that was previously unknown in early branching avialans. Expression of this phenotype (and presumed ecology) in a stem bird underscores that consolidation to the neornithine-like, premaxilla-dominated rostrum was not an evolutionary prerequisite for beak enlargement.
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Affiliation(s)
- Patrick M O'Connor
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA. .,Ohio Center for Ecological and Evolutionary Studies, Ohio University, Athens, OH, USA. .,Department of Earth Sciences, Denver Museum of Nature & Science, Denver, CO, USA.
| | - Alan H Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, USA
| | - Joseph R Groenke
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
| | - Ryan N Felice
- Centre for Integrative Anatomy, Department of Cell and Developmental Biology, University College London, London, UK
| | - Raymond R Rogers
- Department of Earth Sciences, Denver Museum of Nature & Science, Denver, CO, USA.,Geology Department, Macalester College, St Paul, MN, USA
| | - David W Krause
- Department of Earth Sciences, Denver Museum of Nature & Science, Denver, CO, USA.,Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, USA
| | - Lydia J Rahantarisoa
- Département de Sciences de la Terre et de l'Environnement, Université d'Antananarivo, Antananarivo, Madagascar
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10
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Schwab JA, Young MT, Neenan JM, Walsh SA, Witmer LM, Herrera Y, Allain R, Brochu CA, Choiniere JN, Clark JM, Dollman KN, Etches S, Fritsch G, Gignac PM, Ruebenstahl A, Sachs S, Turner AH, Vignaud P, Wilberg EW, Xu X, Zanno LE, Brusatte SL. Inner ear sensory system changes as extinct crocodylomorphs transitioned from land to water. Proc Natl Acad Sci U S A 2020; 117:10422-10428. [PMID: 32312812 PMCID: PMC7229756 DOI: 10.1073/pnas.2002146117] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Major evolutionary transitions, in which animals develop new body plans and adapt to dramatically new habitats and lifestyles, have punctuated the history of life. The origin of cetaceans from land-living mammals is among the most famous of these events. Much earlier, during the Mesozoic Era, many reptile groups also moved from land to water, but these transitions are more poorly understood. We use computed tomography to study changes in the inner ear vestibular system, involved in sensing balance and equilibrium, as one of these groups, extinct crocodile relatives called thalattosuchians, transitioned from terrestrial ancestors into pelagic (open ocean) swimmers. We find that the morphology of the vestibular system corresponds to habitat, with pelagic thalattosuchians exhibiting a more compact labyrinth with wider semicircular canal diameters and an enlarged vestibule, reminiscent of modified and miniaturized labyrinths of other marine reptiles and cetaceans. Pelagic thalattosuchians with modified inner ears were the culmination of an evolutionary trend with a long semiaquatic phase, and their pelagic vestibular systems appeared after the first changes to the postcranial skeleton that enhanced their ability to swim. This is strikingly different from cetaceans, which miniaturized their labyrinths soon after entering the water, without a prolonged semiaquatic stage. Thus, thalattosuchians and cetaceans became secondarily aquatic in different ways and at different paces, showing that there are different routes for the same type of transition.
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Affiliation(s)
- Julia A Schwab
- School of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom;
| | - Mark T Young
- School of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom
| | - James M Neenan
- Oxford University Museum of Natural History, OX1 3PW Oxford, United Kingdom
| | - Stig A Walsh
- School of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom
- Department of Natural Sciences, National Museum of Scotland, EH1 1JF Edinburgh, United Kingdom
| | - Lawrence M Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701
| | - Yanina Herrera
- Consejo Nacional de Investigaciones Científicas y Técnicas, División Paleontología Vertebrados, Museo de La Plata, Facultad de Ciencias Naturales y Museo, National University of La Plata, B1900 La Plata, Buenos Aires, Argentina
| | - Ronan Allain
- Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements, Muséum National d'Histoire Naturelle, 75005 Paris, France
| | - Christopher A Brochu
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, IA 52242
| | - Jonah N Choiniere
- Evolutionary Studies Institute, University of the Witwatersrand, 2000 Johannesburg, South Africa
| | - James M Clark
- Department of Biological Sciences, George Washington University, Washington, DC 20052
| | - Kathleen N Dollman
- Evolutionary Studies Institute, University of the Witwatersrand, 2000 Johannesburg, South Africa
- School of Geosciences, University of the Witwatersrand, 2000 Johannesburg, South Africa
| | - Steve Etches
- Museum of Jurassic Marine Life, BH20 5PE Kimmeridge, United Kingdom
| | - Guido Fritsch
- Department of Reproduction Management, Leibniz Institute for Zoo and Wildlife Research, 10315 Berlin, Germany
| | - Paul M Gignac
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK 74107
| | | | - Sven Sachs
- Abteilung Geowissenschaften, Naturkunde-Museum Bielefeld, Abteilung Geowissenschaften, 33602 Bielefeld, Germany
| | - Alan H Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794
| | - Patrick Vignaud
- Laboratoire de Paléontologie, Evolution, Paléoécosystèmes et Paléoprimatologie, CNRS UMR 7262, Department of Geosciences, University of Poitiers, 86073 Poitiers Cedex 9, France
| | - Eric W Wilberg
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794
| | - Xing Xu
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, 100044 Beijing, China
| | - Lindsay E Zanno
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC 27601
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695
| | - Stephen L Brusatte
- School of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom
- Department of Natural Sciences, National Museum of Scotland, EH1 1JF Edinburgh, United Kingdom
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11
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Schwab JA, Young MT, Neenan JM, Walsh SA, Witmer LM, Herrera Y, Allain R, Brochu CA, Choiniere JN, Clark JM, Dollman KN, Etches S, Fritsch G, Gignac PM, Ruebenstahl A, Sachs S, Turner AH, Vignaud P, Wilberg EW, Xu X, Zanno LE, Brusatte SL. Inner ear sensory system changes as extinct crocodylomorphs transitioned from land to water. Proc Natl Acad Sci U S A 2020. [PMID: 32312812 DOI: 10.11073/pnas.2002146117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/18/2023] Open
Abstract
Major evolutionary transitions, in which animals develop new body plans and adapt to dramatically new habitats and lifestyles, have punctuated the history of life. The origin of cetaceans from land-living mammals is among the most famous of these events. Much earlier, during the Mesozoic Era, many reptile groups also moved from land to water, but these transitions are more poorly understood. We use computed tomography to study changes in the inner ear vestibular system, involved in sensing balance and equilibrium, as one of these groups, extinct crocodile relatives called thalattosuchians, transitioned from terrestrial ancestors into pelagic (open ocean) swimmers. We find that the morphology of the vestibular system corresponds to habitat, with pelagic thalattosuchians exhibiting a more compact labyrinth with wider semicircular canal diameters and an enlarged vestibule, reminiscent of modified and miniaturized labyrinths of other marine reptiles and cetaceans. Pelagic thalattosuchians with modified inner ears were the culmination of an evolutionary trend with a long semiaquatic phase, and their pelagic vestibular systems appeared after the first changes to the postcranial skeleton that enhanced their ability to swim. This is strikingly different from cetaceans, which miniaturized their labyrinths soon after entering the water, without a prolonged semiaquatic stage. Thus, thalattosuchians and cetaceans became secondarily aquatic in different ways and at different paces, showing that there are different routes for the same type of transition.
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Affiliation(s)
- Julia A Schwab
- School of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom;
| | - Mark T Young
- School of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom
| | - James M Neenan
- Oxford University Museum of Natural History, OX1 3PW Oxford, United Kingdom
| | - Stig A Walsh
- School of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom
- Department of Natural Sciences, National Museum of Scotland, EH1 1JF Edinburgh, United Kingdom
| | - Lawrence M Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701
| | - Yanina Herrera
- Consejo Nacional de Investigaciones Científicas y Técnicas, División Paleontología Vertebrados, Museo de La Plata, Facultad de Ciencias Naturales y Museo, National University of La Plata, B1900 La Plata, Buenos Aires, Argentina
| | - Ronan Allain
- Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements, Muséum National d'Histoire Naturelle, 75005 Paris, France
| | - Christopher A Brochu
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, IA 52242
| | - Jonah N Choiniere
- Evolutionary Studies Institute, University of the Witwatersrand, 2000 Johannesburg, South Africa
| | - James M Clark
- Department of Biological Sciences, George Washington University, Washington, DC 20052
| | - Kathleen N Dollman
- Evolutionary Studies Institute, University of the Witwatersrand, 2000 Johannesburg, South Africa
- School of Geosciences, University of the Witwatersrand, 2000 Johannesburg, South Africa
| | - Steve Etches
- Museum of Jurassic Marine Life, BH20 5PE Kimmeridge, United Kingdom
| | - Guido Fritsch
- Department of Reproduction Management, Leibniz Institute for Zoo and Wildlife Research, 10315 Berlin, Germany
| | - Paul M Gignac
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK 74107
| | | | - Sven Sachs
- Abteilung Geowissenschaften, Naturkunde-Museum Bielefeld, Abteilung Geowissenschaften, 33602 Bielefeld, Germany
| | - Alan H Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794
| | - Patrick Vignaud
- Laboratoire de Paléontologie, Evolution, Paléoécosystèmes et Paléoprimatologie, CNRS UMR 7262, Department of Geosciences, University of Poitiers, 86073 Poitiers Cedex 9, France
| | - Eric W Wilberg
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794
| | - Xing Xu
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, 100044 Beijing, China
| | - Lindsay E Zanno
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC 27601
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695
| | - Stephen L Brusatte
- School of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom
- Department of Natural Sciences, National Museum of Scotland, EH1 1JF Edinburgh, United Kingdom
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12
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Noto CR, Drumheller SK, Adams TL, Turner AH. An Enigmatic Small Neosuchian Crocodyliform from the Woodbine Formation of Texas. Anat Rec (Hoboken) 2019; 303:801-812. [PMID: 31173481 DOI: 10.1002/ar.24174] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 11/22/2018] [Accepted: 11/29/2018] [Indexed: 11/05/2022]
Abstract
New discoveries at the Arlington Archosaur Site (AAS), a Cenomanian (Late Cretaceous) locality in north-central Texas, are filling gaps in our knowledge of mid-Cretaceous Appalachian ecosystems, which remain poorly characterized. The AAS is notable because it preserves a diverse crocodyliform record. As seen in other sites that preserve four or more crocodyliform taxa, the species present at the AAS exhibit different snout shapes and body sizes, indicating that this high diversity of sympatric species was likely sustainable due to niche partitioning. Here we describe Scolomastax sahlsteini gen. et sp. nov., a new species of crocodyliform from the AAS, currently known from a partial right mandibular ramus. This species differs from other crocodyliforms in possessing features associated with durophagy or omnivory, including a shortened mandible, reduced tooth count, heterodonty, a dorsally expanded surangular, and enlarged attachments for jaw adductor muscles. Our phylogenetic analysis places this new taxon within Eusuchia as a member of Paralligatoridae and sister taxon to Paralligator gradilifrons. Scolomastax sahlsteini extends the record of paralligatorids into the Late Cretaceous of North America. This discovery represents the first appearance of this clade on the poorly known landmass of Appalachia, supporting a biogeographic connection between North America and Asia in the Early Cretaceous prior to completion of the Western Interior Seaway. However, relationships among other endemic crocodyliforms and tree instability within Paralligatoridae suggest further analysis is needed to resolve phylogenetic and biogeographic relationships (http://zoobank.org/urn:lsid:zoobank.org:pub:DC114471-6687-4BB5-8FAE-96F7278B1DAF). Anat Rec, 303:801-812, 2020. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Christopher R Noto
- Department of Biological Sciences, University of Wisconsin-Parkside, Kenosha, Wisconsin
| | - Stephanie K Drumheller
- Department of Earth and Planetary Sciences, University of Tennessee-Knoxville, Knoxville, Tennessee
| | | | - Alan H Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York
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13
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Nesbitt SJ, Denton RK, Loewen MA, Brusatte SL, Smith ND, Turner AH, Kirkland JI, McDonald AT, Wolfe DG. A mid-Cretaceous tyrannosauroid and the origin of North American end-Cretaceous dinosaur assemblages. Nat Ecol Evol 2019; 3:892-899. [DOI: 10.1038/s41559-019-0888-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/27/2019] [Indexed: 11/09/2022]
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14
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Griffin CT, Bano LS, Turner AH, Smith ND, Irmis RB, Nesbitt SJ. Integrating gross morphology and bone histology to assess skeletal maturity in early dinosauromorphs: new insights from Dromomeron (Archosauria: Dinosauromorpha). PeerJ 2019; 7:e6331. [PMID: 30775169 PMCID: PMC6375289 DOI: 10.7717/peerj.6331] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 12/20/2018] [Indexed: 12/16/2022] Open
Abstract
Understanding growth patterns is central to properly interpreting paleobiological signals in tetrapods, but assessing skeletal maturity in some extinct clades may be difficult when growth patterns are poorly constrained by a lack of ontogenetic series. To overcome this difficulty in assessing the maturity of extinct archosaurian reptiles—crocodylians, birds and their extinct relatives—many studies employ bone histology to observe indicators of the developmental stage reached by a given individual. However, the relationship between gross morphological and histological indicators of maturity has not been examined in most archosaurian groups. In this study, we examined the gross morphology of a hypothesized growth series of Dromomeron romeri femora (96.6–144.4 mm long), the first series of a non-dinosauriform dinosauromorph available for such a study. We also histologically sampled several individuals in this growth series. Previous studies reported that D. romeri lacks well-developed rugose muscle scars that appear during ontogeny in closely related dinosauromorph taxa, so integrating gross morphology and histological signal is needed to determine reliable maturity indicators for early bird-line archosaurs. We found that, although there are small, linear scars indicating muscle attachment sites across the femur, the only rugose muscle scar that appears during ontogeny is the attachment of the M. caudofemoralis longus, and only in the largest-sampled individual. This individual is also the only femur with histological indicators that asymptotic size had been reached, although smaller individuals possess some signal of decreasing growth rates (e.g., decreasing vascular density). The overall femoral bone histology of D. romeri is similar to that of other early bird-line archosaurs (e.g., woven-bone tissue, moderately to well-vascularized, longitudinal vascular canals). All these data indicate that the lack of well-developed femoral scars is autapomorphic for this species, not simply an indication of skeletal immaturity. We found no evidence of the high intraspecific variation present in early dinosaurs and other dinosauriforms, but a limited sample size of other early bird-line archosaur growth series make this tentative. The evolutionary history and phylogenetic signal of gross morphological features must be considered when assessing maturity in extinct archosaurs and their close relatives, and in some groups corroboration with bone histology or with better-known morphological characters is necessary.
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Affiliation(s)
| | - Lauren S Bano
- Department of Biology, Virginia Tech, Blacksburg, VA, USA
| | - Alan H Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, USA
| | - Nathan D Smith
- The Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, CA, USA
| | - Randall B Irmis
- Natural History Museum of Utah, University of Utah, Salt Lake City, UT, USA.,Department of Geology and Geophysics, University of Utah, Salt Lake City, UT, USA
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15
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Abstract
Extant crocodylomorphs are semiaquatic ambush predators largely restricted to freshwater or estuarine environments, but the group is ancestrally terrestrial and inhabited a variety of ecosystems in the past. Despite its rich ecological history, little effort has focused on elucidating the historical pattern of ecological transitions in the group. Traditional views suggested a single shift from terrestrial to aquatic in the Early Jurassic. However, new fossil discoveries and phylogenetic analyses tend to imply a multiple-shift model. Here we estimate ancestral habitats across a comprehensive phylogeny and show at least three independent shifts from terrestrial to aquatic and numerous other habitat transitions. Neosuchians first invade freshwater habitats in the Jurassic, with up to four subsequent shifts into the marine realm. Thalattosuchians first appear in marine habitats in the Early Jurassic. Freshwater semiaquatic mahajangasuchids are derived from otherwise terrestrial notosuchians. Within nearly all marine groups, some species return to freshwater environments. Only twice have crocodylomorphs reverted from aquatic to terrestrial habitats, both within the crown group. All living non-alligatorid crocodylians have a keratinised tongue with salt-excreting glands, but the lack of osteological correlates for these adaptations complicates pinpointing their evolutionary origin or loss. Based on the pattern of transitions to the marine realm, our analysis suggests at least four independent origins of saltwater tolerance in Crocodylomorpha.
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Affiliation(s)
- Eric W Wilberg
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, 11794, USA.
| | - Alan H Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Christopher A Brochu
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, IA, 52242, USA
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Smaers JB, Turner AH, Gómez-Robles A, Sherwood CC. A cerebellar substrate for cognition evolved multiple times independently in mammals. eLife 2018; 7:e35696. [PMID: 29809137 PMCID: PMC6003771 DOI: 10.7554/elife.35696] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 05/21/2018] [Indexed: 12/21/2022] Open
Abstract
Given that complex behavior evolved multiple times independently in different lineages, a crucial question is whether these independent evolutionary events coincided with modifications to common neural systems. To test this question in mammals, we investigate the lateral cerebellum, a neurobiological system that is novel to mammals, and is associated with higher cognitive functions. We map the evolutionary diversification of the mammalian cerebellum and find that relative volumetric changes of the lateral cerebellar hemispheres (independent of cerebellar size) are correlated with measures of domain-general cognition in primates, and are characterized by a combination of parallel and convergent shifts towards similar levels of expansion in distantly related mammalian lineages. Results suggest that multiple independent evolutionary occurrences of increased behavioral complexity in mammals may at least partly be explained by selection on a common neural system, the cerebellum, which may have been subject to multiple independent neurodevelopmental remodeling events during mammalian evolution.
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Affiliation(s)
- Jeroen B Smaers
- Department of AnthropologyStony Brook UniversityNew YorkUnited States
- Center for the Advanced Study of Human PaleobiologyStony Brook UniversityNew YorkUnited States
| | - Alan H Turner
- Department of Anatomical SciencesStony Brook UniversityNew YorkUnited States
| | - Aida Gómez-Robles
- Department of Genetics, Evolution and EnvironmentUniversity College LondonLondonUnited Kingdom
- Department of AnthropologyThe George Washington UniversityWashingtonUnited States
| | - Chet C Sherwood
- Department of AnthropologyThe George Washington UniversityWashingtonUnited States
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17
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Laing AM, Doyle S, Gold MEL, Nesbitt SJ, O'Leary MA, Turner AH, Wilberg EW, Poole KE. Giant taxon-character matrices: the future of morphological systematics. Cladistics 2017; 34:333-335. [DOI: 10.1111/cla.12197] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/20/2017] [Indexed: 11/28/2022] Open
Affiliation(s)
- Adam M. Laing
- Department of Anatomical Sciences; HSC T-8 (040); Stony Brook University; Stony Brook NY 11794-8081 USA
| | - Sharon Doyle
- Interdepartmental Doctoral Program in Anthropological Sciences; Social and Behavioral Sciences Building; Stony Brook University; Stony Brook NY 11794-4364 USA
| | - Maria Eugenia Leone Gold
- Department of Anatomical Sciences; HSC T-8 (040); Stony Brook University; Stony Brook NY 11794-8081 USA
| | - Sterling J. Nesbitt
- Department of Geosciences; Derring Hall; Virginia Polytechnic Institute and State University; Blacksburg VA 24061 USA
| | - Maureen A. O'Leary
- Department of Anatomical Sciences; HSC T-8 (040); Stony Brook University; Stony Brook NY 11794-8081 USA
| | - Alan H. Turner
- Department of Anatomical Sciences; HSC T-8 (040); Stony Brook University; Stony Brook NY 11794-8081 USA
| | - Eric W. Wilberg
- Department of Anatomical Sciences; HSC T-8 (040); Stony Brook University; Stony Brook NY 11794-8081 USA
| | - Karen E. Poole
- Department of Anatomical Sciences; HSC T-8 (040); Stony Brook University; Stony Brook NY 11794-8081 USA
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18
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Turner AH, Pritchard AC, Matzke NJ. Empirical and Bayesian approaches to fossil-only divergence times: A study across three reptile clades. PLoS One 2017; 12:e0169885. [PMID: 28187191 PMCID: PMC5302793 DOI: 10.1371/journal.pone.0169885] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 12/23/2016] [Indexed: 11/19/2022] Open
Abstract
Estimating divergence times on phylogenies is critical in paleontological and neontological studies. Chronostratigraphically-constrained fossils are the only direct evidence of absolute timing of species divergence. Strict temporal calibration of fossil-only phylogenies provides minimum divergence estimates, and various methods have been proposed to estimate divergences beyond these minimum values. We explore the utility of simultaneous estimation of tree topology and divergence times using BEAST tip-dating on datasets consisting only of fossils by using relaxed morphological clocks and birth-death tree priors that include serial sampling (BDSS) at a constant rate through time. We compare BEAST results to those from the traditional maximum parsimony (MP) and undated Bayesian inference (BI) methods. Three overlapping datasets were used that span 250 million years of archosauromorph evolution leading to crocodylians. The first dataset focuses on early Sauria (31 taxa, 240 chars.), the second on early Archosauria (76 taxa, 400 chars.) and the third on Crocodyliformes (101 taxa, 340 chars.). For each dataset three time-calibrated trees (timetrees) were calculated: a minimum-age timetree with node ages based on earliest occurrences in the fossil record; a 'smoothed' timetree using a range of time added to the root that is then averaged over zero-length internodes; and a tip-dated timetree. Comparisons within datasets show that the smoothed and tip-dated timetrees provide similar estimates. Only near the root node do BEAST estimates fall outside the smoothed timetree range. The BEAST model is not able to overcome limited sampling to correctly estimate divergences considerably older than sampled fossil occurrence dates. Conversely, the smoothed timetrees consistently provide node-ages far older than the strict dates or BEAST estimates for morphologically conservative sister-taxa when they sit on long ghost lineages. In this latter case, the relaxed-clock model appears to be correctly moderating the node-age estimate based on the limited morphological divergence. Topologies are generally similar across analyses, but BEAST trees for crocodyliforms differ when clades are deeply nested but contain very old taxa. It appears that the constant-rate sampling assumption of the BDSS tree prior influences topology inference by disfavoring long, unsampled branches.
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Affiliation(s)
- Alan H. Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York, United States of America
| | - Adam C. Pritchard
- Department of Geology, Yale University, New Haven, Connecticut, United States of America
| | - Nicholas J. Matzke
- Division of Ecology, Evolution, and Genetics, Research School of Biology, The Australian National University, Canberra, Australia
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19
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Lessner EJ, Stocker MR, Smith ND, Turner AH, Irmis RB, Nesbitt SJ. A new rauisuchid (Archosauria, Pseudosuchia) from the Upper Triassic (Norian) of New Mexico increases the diversity and temporal range of the clade. PeerJ 2016; 4:e2336. [PMID: 27651983 PMCID: PMC5018681 DOI: 10.7717/peerj.2336] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/17/2016] [Indexed: 11/20/2022] Open
Abstract
Rauisuchids are large (2–6 m in length), carnivorous, and quadrupedal pseudosuchian archosaurs closely related to crocodylomorphs. Though geographically widespread, fossils of this clade are relatively rare in Late Triassic assemblages. The middle Norian (∼212 Ma) Hayden Quarry of northern New Mexico, USA, in the Petrified Forest Member of the Chinle Formation, has yielded isolated postcranial elements and associated skull elements of a new species of rauisuchid. Vivaron haydeni gen. et. sp. nov. is diagnosed by the presence of two posteriorly directed prongs at the posterior end of the maxilla for articulation with the jugal. The holotype maxilla and referred elements are similar to those of the rauisuchid Postosuchus kirkpatricki from the southwestern United States, but V. haydeni shares several maxillary apomorphies (e.g., a distinct dropoff to the antorbital fossa that is not a ridge, a straight ventral margin, and a well defined dental groove) with the rauisuchid Teratosaurus suevicus from the Norian of Germany. Despite their geographic separation, this morphological evidence implies a close phylogenetic relationship between V. haydeni and T. suevicus. The morphology preserved in the new Hayden Quarry rauisuchid V. haydeni supports previously proposed and new synapomorphies for nodes within Rauisuchidae. The discovery of Vivaron haydeni reveals an increased range of morphological disparity for rauisuchids from the low-paleolatitude Chinle Formation and a clear biogeographic connection with high paleolatitude Pangea.
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Affiliation(s)
- Emily J Lessner
- Department of Geosciences, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States; Department of Biological Sciences, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States
| | - Michelle R Stocker
- Department of Geosciences, Virginia Polytechnic Institute and State University (Virginia Tech) , Blacksburg, VA , United States
| | - Nathan D Smith
- The Dinosaur Institute, Natural History Museum of Los Angeles County , Los Angeles, CA , United States
| | - Alan H Turner
- Department of Anatomical Sciences, Stony Brook University , Stony Brook, NY , United States
| | - Randall B Irmis
- Natural History Museum of Utah, University of Utah, Salt Lake City, UT, United States; Department of Geology and Geophysics, University of Utah, Salt Lake City, UT, United States
| | - Sterling J Nesbitt
- Department of Geosciences, Virginia Polytechnic Institute and State University (Virginia Tech) , Blacksburg, VA , United States
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20
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Balanoff AM, Smaers JB, Turner AH. Brain modularity across the theropod-bird transition: testing the influence of flight on neuroanatomical variation. J Anat 2015; 229:204-14. [PMID: 26538376 DOI: 10.1111/joa.12403] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2015] [Indexed: 11/29/2022] Open
Abstract
Living birds constitute the only vertebrate group whose brain volume relative to body size approaches the uniquely expanded values expressed by mammals. The broad suite of complex behaviors exhibited by crown-group birds, including sociality, vocal learning, parental care, and flying, suggests the origins of their encephalization was likely driven by a mosaic of selective pressures. If true, the historical pattern of brain expansion may be more complex than either a gradual expansion, as proposed by early studies of the avian brain, or a sudden expansion correlating with the appearance of flight. The origins of modern avian neuroanatomy are obscured by the more than 100 million years of evolution along their phylogenetic stem (from the origin of the modern radiation in the Middle Jurassic to the split from crocodile-line archosaurs). Here we use phylogenetic comparative approaches to explore which evolutionary scenarios best explain variation in measured volumes of digitally partitioned endocasts of modern birds and their non-avian ancestors. Our analyses suggest that variation in the relative volumes of the endocranium and cerebrum explain most of the structural variation in this lineage. Generalized multi-regime Ornstein-Uhlenbeck (OU) models suggest that powered flight does not appear to be a driver of observed variation, reinforcing the hypothesis that the deep history of the avian brain is complex, with nuances still to be discovered.
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Affiliation(s)
- Amy M Balanoff
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, USA
| | - Jeroen B Smaers
- Department of Anthropology, Stony Brook University, Stony Brook, NY, USA
| | - Alan H Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, USA
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21
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Molnar JL, Pierce SE, Bhullar BAS, Turner AH, Hutchinson JR. Morphological and functional changes in the vertebral column with increasing aquatic adaptation in crocodylomorphs. R Soc Open Sci 2015; 2:150439. [PMID: 26716001 PMCID: PMC4680616 DOI: 10.1098/rsos.150439] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 10/07/2015] [Indexed: 05/26/2023]
Abstract
The lineage leading to modern Crocodylia has undergone dramatic evolutionary changes in morphology, ecology and locomotion over the past 200+ Myr. These functional innovations may be explained in part by morphological changes in the axial skeleton, which is an integral part of the vertebrate locomotor system. Our objective was to estimate changes in osteological range of motion (RoM) and intervertebral joint stiffness of thoracic and lumbar vertebrae with increasing aquatic adaptation in crocodylomorphs. Using three-dimensional virtual models and morphometrics, we compared the modern crocodile Crocodylus to five extinct crocodylomorphs: Terrestrisuchus, Protosuchus, Pelagosaurus, Steneosaurus and Metriorhynchus, which span the spectrum from terrestrial to fully aquatic. In Crocodylus, we also experimentally measured changes in trunk flexibility with sequential removal of osteoderms and soft tissues. Our results for the more aquatic species matched our predictions fairly well, but those for the more terrestrial early crocodylomorphs did not. A likely explanation for this lack of correspondence is the influence of other axial structures, particularly the rigid series of dorsal osteoderms in early crocodylomorphs. The most important structures for determining RoM and stiffness of the trunk in Crocodylus were different in dorsoventral versus mediolateral bending, suggesting that changes in osteoderm and rib morphology over crocodylomorph evolution would have affected movements in some directions more than others.
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Affiliation(s)
- Julia L. Molnar
- Department of Anatomy, Howard University College of Medicine, Washington, DC 20059, USA
- Structure and Motion Lab, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire AL9 7TA, UK
| | - Stephanie E. Pierce
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Structure and Motion Lab, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire AL9 7TA, UK
| | | | - Alan H. Turner
- Department of Anatomical Sciences, Stonybrook University, Stony Brook, NY 11794, USA
| | - John R. Hutchinson
- Structure and Motion Lab, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire AL9 7TA, UK
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22
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Abstract
The crocodyliform Shamosuchus is known from numerous Late Cretaceous localities in southern and eastern Mongolia and fragmentary remains from Uzbekistan. Seven species of Shamosuchus have been named from six localities in Mongolia and three in Uzbekistan. Six species originally described as Paralligator were later referred to Shamosuchus. Only the type species, Shamosuchus djadochtaensis has been examined in detail. Many of the named species of Shamosuchus show striking similarity in size and cranial morphology but most are based on partial remains suggesting that the true species diversity is overestimated. A review of all species referred to Shamosuchus recognizes three valid taxa: Shamosuchus djadochtaensis, S. gradilifrons, and S. major. Shamosuchus sungaricus, S. borealis, and S. karakalpakensis are nomena dubia, whereas S. ancestralis, S. ulgicus, S. tersus, and S. ulanicus are junior subjective synonyms of S. gradilifrons. Phylogenetic analysis of 318 phenotypic characters recovers a Paralligatoridae clade consisting of Shamosuchus, Rugosuchus, Batrachomimus, Glen Rose Form, and Wannchampsus. Shamosuchus is non-monophyletic: S. djadochtaensis is near the base of Paralligatoridae whereas S. gradilifrons + S. major are the most deeply nested. The name Paralligator is resurrected for this clade. Rugosuchus and Batrachomimus are sister taxa to Paralligator. Paralligatoridae is closely related to Theriosuchus, hylaeochampsids and a speciose Allodaposuchus clade, which together are the sister group of Borealosuchus plus Crocodylia. These results support the presence of a diverse clade in eastern Asia and western North America throughout the Cretaceous with origins in the Late Jurassic.
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Affiliation(s)
- Alan H. Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York, United States of America
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23
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Turner AH, Pritchard AC. The monophyly of Susisuchidae (Crocodyliformes) and its phylogenetic placement in Neosuchia. PeerJ 2015; 3:e759. [PMID: 25699208 PMCID: PMC4330912 DOI: 10.7717/peerj.759] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 01/21/2015] [Indexed: 11/20/2022] Open
Abstract
Eusuchian crocodyliforms, which include all living crocodylians, have historically been characterized by two anatomical specializations: a ball-in-socket vertebral joint and an extensive secondary hard palate with a pterygoid-bound internal choana. The Early Cretaceous neosuchian clade Susisuchidae is typically regarded as phylogenetically near Eusuchia. The putative susisuchid Isisfordia duncani was initially described as a transitional form exhibiting incipient versions of these eusuchian traits. Here we examine aspects of the morphology of Isisfordia and comment on the morphology of its putative sister taxon Susisuchus. Our reexamination supports the notion of Isisfordia possessing transitional vertebral morphology but we present a new interpretation of its palate construction that shows it to be more plesiomorphic than previously thought. The secondary choana of Isisfordia is not pterygoid bound. Instead, long palatines expand distally lapping under the pterygoid to form the anterior border of the choana as is common among many advanced neosuchians. Incorporation of these observations into an expanded phylogenetic dataset of neosuchian crocodyliforms results in a new phylogenetic hypothesis for Susisuchidae. Isisfordia and Susisuchus form a monophyletic Susisuchidae that sits near the base of Neosuchia, and is not the sister taxon of Eusuchia.
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Affiliation(s)
- Alan H. Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, USA
| | - Adam C. Pritchard
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, USA
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24
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Han G, Chiappe LM, Ji SA, Habib M, Turner AH, Chinsamy A, Liu X, Han L. A new raptorial dinosaur with exceptionally long feathering provides insights into dromaeosaurid flight performance. Nat Commun 2014; 5:4382. [PMID: 25025742 DOI: 10.1038/ncomms5382] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 06/11/2014] [Indexed: 11/09/2022] Open
Abstract
Microraptorines are a group of predatory dromaeosaurid theropod dinosaurs with aerodynamic capacity. These close relatives of birds are essential for testing hypotheses explaining the origin and early evolution of avian flight. Here we describe a new 'four-winged' microraptorine, Changyuraptor yangi, from the Early Cretaceous Jehol Biota of China. With tail feathers that are nearly 30 cm long, roughly 30% the length of the skeleton, the new fossil possesses the longest known feathers for any non-avian dinosaur. Furthermore, it is the largest theropod with long, pennaceous feathers attached to the lower hind limbs (that is, 'hindwings'). The lengthy feathered tail of the new fossil provides insight into the flight performance of microraptorines and how they may have maintained aerial competency at larger body sizes. We demonstrate how the low-aspect-ratio tail of the new fossil would have acted as a pitch control structure reducing descent speed and thus playing a key role in landing.
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Affiliation(s)
- Gang Han
- Paleontological Center, Bohai University, 19 Keji Road, New Shongshan District, Jinzhou, Liaoning Province 121013, China
| | - Luis M Chiappe
- Dinosaur Institute, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California 90007, USA
| | - Shu-An Ji
- 1] Paleontological Center, Bohai University, 19 Keji Road, New Shongshan District, Jinzhou, Liaoning Province 121013, China [2] Institute of Geology, Chinese Academy of Geological Sciences, 26 Baiwanzhuang Road, Beijing 100037, China
| | - Michael Habib
- University of Southern California, Health Sciences Campus, BMT 403, Mail Code 9112, Los Angeles, California 90089, USA
| | - Alan H Turner
- Health Science Center, T8 (040), Department of Anatomical Sciences, School of Medicine, Stony Brook University, Stony Brook, New York 11794, USA
| | - Anusuya Chinsamy
- Department of Biological Sciences, University of Cape Town, Private Bag X3, Rhodes Gift 7701, South Africa
| | - Xueling Liu
- Paleontological Center, Bohai University, 19 Keji Road, New Shongshan District, Jinzhou, Liaoning Province 121013, China
| | - Lizhuo Han
- Paleontological Center, Bohai University, 19 Keji Road, New Shongshan District, Jinzhou, Liaoning Province 121013, China
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Evans SE, Groenke JR, Jones MEH, Turner AH, Krause DW. New material of Beelzebufo, a hyperossified frog (Amphibia: Anura) from the late cretaceous of Madagascar. PLoS One 2014; 9:e87236. [PMID: 24489877 PMCID: PMC3905036 DOI: 10.1371/journal.pone.0087236] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 12/18/2013] [Indexed: 01/12/2023] Open
Abstract
The extant anuran fauna of Madagascar is exceptionally rich and almost completely endemic. In recent years, many new species have been described and understanding of the history and relationships of this fauna has been greatly advanced by molecular studies, but very little is known of the fossil history of frogs on the island. Beelzebufo ampinga, the first named pre-Holocene frog from Madagascar, was described in 2008 on the basis of numerous disarticulated cranial and postcranial elements from the Upper Cretaceous (Maastrichtian) Maevarano Formation of Madagascar. These specimens documented the presence of a hyperossified taxon that differed strikingly from extant Malagasy frogs in its large size and heavy coarse cranial exostosis. Here we describe and analyse new, articulated, and more complete material of the skull, vertebral column, and hind limb, as well as additional isolated elements discovered since 2008. μCT scans allow a detailed understanding of both internal and external morphology and permit a more accurate reconstruction. The new material shows Beelzebufo to have been even more bizarre than originally interpreted, with large posterolateral skull flanges and sculptured vertebral spine tables. The apparent absence of a tympanic membrane, the strong cranial exostosis, and vertebral morphology suggest it may have burrowed during seasonally arid conditions, which have been interpreted for the Maevarano Formation from independent sedimentological and taphonomic evidence. New phylogenetic analyses, incorporating both morphological and molecular data, continue to place Beelzebufo with hyloid rather than ranoid frogs. Within Hyloidea, Beelzebufo still groups with the South American Ceratophryidae thus continuing to pose difficulties with both biogeographic interpretations and prior molecular divergence dates.
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Affiliation(s)
- Susan E. Evans
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Joseph R. Groenke
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York, United States of America
| | - Marc E. H. Jones
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
- School of Earth and Environmental Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Alan H. Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York, United States of America
| | - David W. Krause
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York, United States of America
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Pritchard AC, Turner AH, Allen ER, Norell MA. Osteology of a North American Goniopholidid (Eutretauranosuchus delfsi) and Palate Evolution in Neosuchia. American Museum Novitates 2013. [DOI: 10.1206/3783.2] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Abstract
AbstractThe first large (>1 m) diapsids appeared near the Permian–Triassic extinction and a subset of diapsids, the archosauriforms, expanded their body size range soon after in the Early–Middle Triassic. Here, we examine body size at key evolutionary events within Archosauriformes during the Triassic and through the end-Triassic extinction. Using femoral length as a body size proxy and a temporally calibrated phylogeny of Archosauriformes, we estimate ancestral body sizes using a maximum likelihood approach and test for the presence of an adapative radiation by comparing the fit of competing evolutionary models. Archosauriform body size is characterized by punctuated change with more change occurring early in the Triassic. Archosaurs crossing the Triassic–Jurassic boundary show a wide range in ancestral size, and dinosaurs (sauropodomorphs and theropods) are considerably larger in the Jurassic. Crocodylomorph origins are characterized by a drop in body size; however, both the relative amount of change and the rate of change are matched among other archosaur clades. Archosauriforms increase in absolute body size through the Triassic and evidence suggests that a directional trend in size increase occurred in the early Mesozoic. The morphological signature of adaptive radiation is rare in comparative data from extant animals but is present at the origination of Archosauriformes.
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Affiliation(s)
- Alan H. Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794, USA
- Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA
| | - Sterling J. Nesbitt
- Department of Biology, University of Washington, Seattle, WA 98195, USA
- Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA
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Brusatte SL, Vremir M, Csiki-Sava Z, Turner AH, Watanabe A, Erickson GM, Norell MA. The Osteology of Balaur bondoc, an Island-Dwelling Dromaeosaurid (Dinosauria: Theropoda) from the Late Cretaceous of Romania. Bulletin of the American Museum of Natural History 2013. [DOI: 10.1206/798.1] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Turner AH, Makovicky PJ, Norell MA. A Review of Dromaeosaurid Systematics and Paravian Phylogeny. Bulletin of the American Museum of Natural History 2012. [DOI: 10.1206/748.1] [Citation(s) in RCA: 207] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Turner AH, Pol D, Norell MA. Anatomy ofMahakala omnogovae(Theropoda: Dromaeosauridae), Tögrögiin Shiree, Mongolia. American Museum Novitates 2011. [DOI: 10.1206/3722.2] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Erickson GM, Rauhut OWM, Zhou Z, Turner AH, Inouye BD, Hu D, Norell MA. Was dinosaurian physiology inherited by birds? Reconciling slow growth in archaeopteryx. PLoS One 2009; 4:e7390. [PMID: 19816582 PMCID: PMC2756958 DOI: 10.1371/journal.pone.0007390] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2009] [Accepted: 09/16/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Archaeopteryx is the oldest and most primitive known bird (Avialae). It is believed that the growth and energetic physiology of basalmost birds such as Archaeopteryx were inherited in their entirety from non-avialan dinosaurs. This hypothesis predicts that the long bones in these birds formed using rapidly growing, well-vascularized woven tissue typical of non-avialan dinosaurs. METHODOLOGY/PRINCIPAL FINDINGS We report that Archaeopteryx long bones are composed of nearly avascular parallel-fibered bone. This is among the slowest growing osseous tissues and is common in ectothermic reptiles. These findings dispute the hypothesis that non-avialan dinosaur growth and physiology were inherited in totality by the first birds. Examining these findings in a phylogenetic context required intensive sampling of outgroup dinosaurs and basalmost birds. Our results demonstrate the presence of a scale-dependent maniraptoran histological continuum that Archaeopteryx and other basalmost birds follow. Growth analysis for Archaeopteryx suggests that these animals showed exponential growth rates like non-avialan dinosaurs, three times slower than living precocial birds, but still within the lowermost range for all endothermic vertebrates. CONCLUSIONS/SIGNIFICANCE The unexpected histology of Archaeopteryx and other basalmost birds is actually consistent with retention of the phylogenetically earlier paravian dinosaur condition when size is considered. The first birds were simply feathered dinosaurs with respect to growth and energetic physiology. The evolution of the novel pattern in modern forms occurred later in the group's history.
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Affiliation(s)
- Gregory M Erickson
- Department of Biological Science, Florida State University, Tallahassee, Florida, USA.
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Abstract
The furcula is a structure formed by the midline fusion of the clavicles. This is the element which is unique to theropods and is important for understanding the link between birds and other theropods. New specimens from basal theropods suggest that the furcula appeared very early in theropod history. We review furcula development, function, and morphology, as well as the anatomical terminology applied to it. Furcular morphology is highly variable in crown-group avians but is rather conserved among nonavian theropods. Here we review, or describe for the first time, the furculae in many nonavian theropods. Furculae occur in nearly all major clades of theropods, as shown by new theropod specimens from the Early Cretaceous of China and a close inspection of previously collected specimens. Informative phylogenetic characters pertaining to the furcula occur throughout Theropoda, though care should betake to consider taphonomic effects when describing furcular morphology.
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Affiliation(s)
- Sterling J Nesbitt
- Division of Paleontology, American Museum of Natural History, New York, New York 10024, USA.
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Turner AH, Nesbitt SJ, Norell MA. A Large Alvarezsaurid from the Late Cretaceous of Mongolia. American Museum Novitates 2009. [DOI: 10.1206/639.1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Singh I, Quinn H, Mok M, Southgate RJ, Turner AH, Li D, Sinclair AJ, Hawley JA. The effect of exercise and training status on platelet activation: Do cocoa polyphenols play a role? Platelets 2009; 17:361-7. [PMID: 16973496 DOI: 10.1080/09537100600746953] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Sedentary and trained men respond differently to the same intensity of exercise, this is probably related to their platelet reactivity and antioxidant capacity. There is growing interest in the utilization of antioxidant-rich plant extracts as dietary food supplements. The aim of this study was to investigate the effect of an acute bout of sub maximal exercise on platelet count and differential response of platelet activation in trained and sedentary subjects and to observe if cocoa polyphenols reverse the effect of exercise on platelet function. The practical significance of this study was that many sedentary people engage in occasional strenuous exercise that may predispose them to risk of heart disease. Fasting blood samples were collected from 16 male subjects, pre and post 1-h cycling exercise at 70% of maximal aerobic power (VO2max) before and after consumption of cocoa or placebo. Agonist stimulated citrated whole blood was utilized for measuring platelet aggregation, adenosine triphosphate (ATP) release and platelet activation. Baseline platelet count (221 +/- 33 x 10(9)/L) and ATP release (1.4 +/- 0.6 nmol) increased significantly (P < 0.05) after exercise in all subjects. Baseline platelet numbers in the trained were higher (P < 0.05) than in the sedentary (235 +/- 37 vs. 208 +/- 34 x 10(9)/L), where as platelet activation in trained was lower (P < 0.05) than sedentary (51 +/- 6 vs. 59 +/- 5%). Seven days of cocoa polyphenol supplementation had little effect on any of the parameters measured. We conclude that trained subjects show decreased activation of stimulated platelets when compared to the sedentary subjects and short-term cocoa polyphenol supplementation did not decrease platelet activity in response to exercise independent of prior training status.
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Affiliation(s)
- I Singh
- Division of Laboratory Medicine, School of Medical Sciences, RMIT University Bundoora, Victoria 3083, Australia.
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Wu EYS, Ade P, Bock J, Bowden M, Brown ML, Cahill G, Castro PG, Church S, Culverhouse T, Friedman RB, Ganga K, Gear WK, Gupta S, Hinderks J, Kovac J, Lange AE, Leitch E, Melhuish SJ, Memari Y, Murphy JA, Orlando A, Piccirillo L, Pryke C, Rajguru N, Rusholme B, Schwarz R, O'Sullivan C, Taylor AN, Thompson KL, Turner AH, Zemcov M. Parity violation constraints using cosmic microwave background polarization spectra from 2006 and 2007 observations by the QUaD polarimeter. Phys Rev Lett 2009; 102:161302. [PMID: 19518694 DOI: 10.1103/physrevlett.102.161302] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 03/13/2009] [Indexed: 05/27/2023]
Abstract
We constrain parity-violating interactions to the surface of last scattering using spectra from the QUaD experiment's second and third seasons of observations by searching for a possible systematic rotation of the polarization directions of cosmic microwave background photons. We measure the rotation angle due to such a possible "cosmological birefringence" to be 0.55 degrees +/-0.82 degrees (random) +/-0.5 degrees (systematic) using QUaD's 100 and 150 GHz temperature-curl and gradient-curl spectra over the spectra over the multipole range 200<l<2000, consistent with null, and constrain Lorentz-violating interactions to <2 x 10;{-43} GeV (68% confidence limit). This is the best constraint to date on electrodynamic parity violation on cosmological scales.
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Affiliation(s)
- E Y S Wu
- Kavli Institute for Particle Astrophysics and Cosmology and Department of Physics, Stanford University, Stanford, California 94305, USA.
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Abstract
Direct evidence of prey choice in carnivorous dinosaurs is rare in the fossil record. The most celebrated example pertains to purported stomach contents in the carnivorous dinosaur Coelophysis bauri, which besides revealing prey choice, also points to cannibalistic behaviour as being commonplace (Colbert 1989, 1995). Here, we test this hypothesis by conducting the first comprehensive anatomical and histological examination of the famed Coelophysis 'cannibals'. The results unequivocally show that the gut contents derive from early crocodylomorphs rather than juveniles of Coelophysis. These findings suggest that this taxon is not cannibalistic and bring into question the commonality of this behaviour among non-avian dinosaurs.
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Affiliation(s)
- Sterling J Nesbitt
- Division of Paleontology, American Museum of Natural History, New York, NY 10024-5192, USA.
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Singh I, Mok M, Christensen AM, Turner AH, Hawley JA. The effects of polyphenols in olive leaves on platelet function. Nutr Metab Cardiovasc Dis 2008; 18:127-132. [PMID: 17346951 DOI: 10.1016/j.numecd.2006.09.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 09/06/2006] [Accepted: 09/08/2006] [Indexed: 10/23/2022]
Abstract
INTRODUCTION The phenolic compounds of olive leaves and olive oils in the Mediterranean diet have been associated with a reduced incidence of heart disease. Accordingly, antioxidant-rich diets may prevent the deleterious effects of oxidative metabolism by scavenging free radicals, thus inhibiting oxidation and delaying atherosclerosis. The process involves phospholipase C activation and arachidonic acid metabolism, and is thought to reduce hydrogen peroxide (H(2)O(2)). In our study, an extract of Olea europaea L. leaves was used. The active phenolic compounds in this extract are part of the secoiridoid family, known for their capacity to scavenge H(2)O(2). The results from this study will help to improve our understanding of effects of polyphenol antioxidants in olive leaf extract on platelet function. METHODS Full blood examination (FBE), platelet aggregation, and ATP release were performed on samples from fasting, normal, healthy male subjects. Platelet function at increasing concentrations of oleuropein was investigated through measures of platelet aggregation and ATP release from activated platelets. RESULTS Blood analysis (n=11) revealed a significant dose-dependant reduction in platelet activity with olive extract concentrations of 1.0% v/v (P<0.001). ATP Release showed a similar pattern (P=0.02). CONCLUSIONS Olive leaf polyphenols derived from O. europaea L. leaves inhibited in vitro platelet activation in healthy, non-smoking males. Further bioavailability studies need to be undertaken to determine the in vivo effect of extract on platelet function and to validate the present results.
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Affiliation(s)
- Indu Singh
- School of Medical Sciences, RMIT University, Melbourne, Australia
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Abstract
Fossil evidence for changes in dinosaurs near the lineage leading to birds and the origin of flight has been sparse. A dinosaur from Mongolia represents the basal divergence within Dromaeosauridae. The taxon's small body size and phylogenetic position imply that extreme miniaturization was ancestral for Paraves (the clade including Avialae, Troodontidae, and Dromaeosauridae), phylogenetically earlier than where flight evolution is strongly inferred. In contrast to the sustained small body sizes among avialans throughout the Cretaceous Period, the two dinosaurian lineages most closely related to birds, dromaeosaurids and troodontids, underwent four independent events of gigantism, and in some lineages size increased by nearly three orders of magnitude. Thus, change in theropod body size leading to flight's origin was not unidirectional.
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Affiliation(s)
- Alan H Turner
- Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA.
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Abstract
Some nonavian theropod dinosaurs were at least partially covered in feathers or filamentous protofeathers. However, a complete understanding of feather distribution among theropod dinosaurs is limited because feathers are typically preserved only in lagerstätten like that of Solnhofen, Germany or Liaoning, China. Such deposits possess clear taphonomic biases toward small-bodied animals, limiting our knowledge regarding feather presence in larger members of feathered clades. We present direct evidence of feathers in Velociraptor mongoliensis based on the presence of quill knobs on the posterior forearm. This report of secondaries in a larger-bodied, derived, and clearly flightless member of a nonavian theropod clade represented by feathered relatives is a substantial contribution to our knowledge of the evolution of feathers.
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Affiliation(s)
- Alan H Turner
- Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA.
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Irmis RB, Nesbitt SJ, Padian K, Smith ND, Turner AH, Woody D, Downs A. A Late Triassic dinosauromorph assemblage from New Mexico and the rise of dinosaurs. Science 2007; 317:358-61. [PMID: 17641198 DOI: 10.1126/science.1143325] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
It has generally been thought that the first dinosaurs quickly replaced more archaic Late Triassic faunas, either by outcompeting them or when the more archaic faunas suddenly became extinct. Fossils from the Hayden Quarry, in the Upper Triassic Chinle Formation of New Mexico, and an analysis of other regional Upper Triassic assemblages instead imply that the transition was gradual. Some dinosaur relatives preserved in this Chinle assemblage belong to groups previously known only from the Middle and lowermost Upper Triassic outside North America. Thus, the transition may have extended for 15 to 20 million years and was probably diachronous at different paleolatitudes.
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Affiliation(s)
- Randall B Irmis
- Museum of Paleontology and Department of Integrative Biology, University of California, Berkeley, CA 94720-4780, USA.
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Singh I, Turner AH, Sinclair AJ, Li D, Hawley JA. Effects of gamma-tocopherol supplementation on thrombotic risk factors. Asia Pac J Clin Nutr 2007; 16:422-8. [PMID: 17704022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
OBJECTIVE The antioxidant activity of vitamin E is derived primarily from alpha-tocopherol (alpha-T) and gamma-tocopherol (gamma-T). Results of epidemiological studies have demonstrated an inverse relationship between vitamin E intake and coronary disease. However, the results of clinical trials using alpha-T are equivocal. We determined the effect of 5 weeks of 100 mg/d or 200 mg/d gamma-T supplementation on thrombotic markers such as platelet reactivity, lipid profile and the inflammation marker C-reactive protein (CRP). METHODS AND RESULTS Fourteen healthy subjects consumed 100 mg/day while 13 consumed 200 mg/d of gamma-T and 12 received placebo (soybean capsules with less than 5 mg/d gamma-T) in a double-blinded parallel study design. Fasting pre and post dose blood samples were analysed. Blood gamma-T concentrations increased significantly (p<0.05) relative to dose during the intervention period. Both groups receiving active ingredients showed significantly lower platelet activation after supplementation (p<0.05). Subjects consuming 100 mg/d gamma-T had significantly decreased LDL cholesterol, platelet aggregation and mean platelet volume (MPV) (p<0.05). Little effect of gamma-T was observed on other parameters. CONCLUSIONS These data suggest that gamma-T supplementation may have a permissive role in decreasing the risk of thrombotic events by improving lipid profile and reducing platelet activity.
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Affiliation(s)
- Indu Singh
- Division of Laboratory Medicine, School of Medical Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083, Australia.
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Affiliation(s)
- J M McIntire
- Physiological Laboratory, Mount Holyoke College, South Hadley
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Krogh A, Landis EM, Turner AH. THE MOVEMENT OF FLUID THROUGH THE HUMAN CAPILLARY WALL IN RELATION TO VENOUS PRESSURE AND TO THE COLLOID OSMOTIC PRESSURE OF THE BLOOD. J Clin Invest 2006; 11:63-95. [PMID: 16694035 PMCID: PMC435798 DOI: 10.1172/jci100408] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- A Krogh
- Laboratory of Zoophysiology, University of Copenhagen, Copenhagen, Denmark
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Affiliation(s)
- A Krogh
- Laboratory of Zoophysiology, University of Copenhagen, Copenhagen, Denmark
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Norell MA, Clark JM, Turner AH, Makovicky PJ, Barsbold R, Rowe T. A New Dromaeosaurid Theropod from Ukhaa Tolgod (Ömnögov, Mongolia). Am Museum Novitates 2006. [DOI: 10.1206/0003-0082(2006)3545[1:andtfu]2.0.co;2] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Abstract
Explanations of the distributions of terrestrial vertebrates during the Mesozoic are currently vigorously contested and debated in palaeobiogeography. Recent studies focusing on dinosaurs yield conflicting hypotheses. Dispersal, coupled with regional extinction or vicariance driven by continental break-up, have been cited as the main causal factors behind dinosaur distributions in the Mesozoic. To expand the scope of the debate and test for vicariance within another terrestrial group, I herein apply a cladistic biogeographical method to a large sample of Cretaceous crocodyliform taxa. A time-slicing methodology is employed and a refinement made to account for the divergence times of the analysed clades. The results provide statistically significant evidence that Gondwana fragmentation affected crocodyliform diversification during the Mid-Late Cretaceous. Detection of a vicariant pattern within crocodyliforms is important as it helps corroborate vicariance hypotheses in other fossil and extant groups as well as furthers the move towards more taxonomically diverse approaches to palaeobiogeographical research.
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Affiliation(s)
- Alan H Turner
- Department of Geoscience, University of Iowa, Iowa City, IA 52242, USA.
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Murphy KJ, Chronopoulos AK, Singh I, Francis MA, Moriarty H, Pike MJ, Turner AH, Mann NJ, Sinclair AJ. Dietary flavanols and procyanidin oligomers from cocoa (Theobroma cacao) inhibit platelet function. Am J Clin Nutr 2003; 77:1466-73. [PMID: 12791625 DOI: 10.1093/ajcn/77.6.1466] [Citation(s) in RCA: 263] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Flavonoids may be partly responsible for some health benefits, including antiinflammatory action and a decreased tendency for the blood to clot. An acute dose of flavanols and oligomeric procyanidins from cocoa powder inhibits platelet activation and function over 6 h in humans. OBJECTIVE This study sought to evaluate whether 28 d of supplementation with cocoa flavanols and related procyanidin oligomers would modulate human platelet reactivity and primary hemostasis and reduce oxidative markers in vivo. DESIGN Thirty-two healthy subjects were assigned to consume active (234 mg cocoa flavanols and procyanidins/d) or placebo (< or = 6 mg cocoa flavanols and procyanidins/d) tablets in a blinded parallel-designed study. Platelet function was determined by measuring platelet aggregation, ATP release, and expression of activation-dependent platelet antigens by using flow cytometry. Plasma was analyzed for oxidation markers and antioxidant status. RESULTS Plasma concentrations of epicatechin and catechin in the active group increased by 81% and 28%, respectively, during the intervention period. The active group had significantly lower P selectin expression and significantly lower ADP-induced aggregation and collagen-induced aggregation than did the placebo group. Plasma ascorbic acid concentrations were significantly higher in the active than in the placebo group (P < 0.05), whereas plasma oxidation markers and antioxidant status did not change in either group. CONCLUSIONS Cocoa flavanol and procyanidin supplementation for 28 d significantly increased plasma epicatechin and catechin concentrations and significantly decreased platelet function. These data support the results of acute studies that used higher doses of cocoa flavanols and procyanidins.
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Affiliation(s)
- Karen J Murphy
- Department of Food Science, RMIT University, Melbourne, Australia.
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Kelly FD, Sinclair AJ, Mann NJ, Turner AH, Raffin FL, Blandford MV, Pike MJ. Short-term diets enriched in stearic or palmitic acids do not alter plasma lipids, platelet aggregation or platelet activation status. Eur J Clin Nutr 2002; 56:490-9. [PMID: 12032647 DOI: 10.1038/sj.ejcn.1601332] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2001] [Revised: 08/21/2001] [Accepted: 09/06/2001] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To determine whether healthy males who consumed increased amounts of dietary stearic acid compared with increased dietary palmitic acid through the consumption of commercially available foods, exhibited any changes in plasma lipids, platelet aggregation or platelet activation status. DESIGN A randomised cross-over dietary intervention. SUBJECTS AND INTERVENTIONS Nine free-living healthy males consumed two experimental diets (stearic acid enriched, diet S, and palmitic acid enriched, diet P) for 3 weeks in a randomised cross-over design separated by a 3 week washout phase. The diets consisted of approximately 30% of energy as fat (30% of which was derived from the treatment diets) providing approximately 13 g/day as stearic acid and 17 g/day as palmitic acid on diet S and approximately 7 g/day as stearic acid and 22 g/day as palmitic acid on diet P. The dietary ratio of stearic to palmitic acids was 0.76 on diet S compared with 0.31 on diet P. Blood samples were collected on days 0 and 21 of each dietary period. RESULTS LDL cholesterol levels and platelet aggregation response to the agonist ADP were significantly decreased (P<0.025) in subjects on diet S compared with day 0. Apart from that, there were no significant changes in plasma lipids, platelet aggregation, mean platelet volume and platelet reactivity between diets. There were no significant changes in stearic or palmitic acid levels in plasma phospholipid or triacylglycerol. There was a significant difference in palmitic acid levels in platelet phospholipids between the two diets. CONCLUSIONS Use of commonly available foods led to a 27% increase in stearic acid (diet S) and a 19% increase in palmitic acid (diet P), on diets S and P respectively, and no significant differences between the two diets in plasma lipoprotein concentrations, platelet aggregation or platelet activation status.
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Affiliation(s)
- F D Kelly
- Department of Food Science, RMIT University, Melbourne, Australia
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Kelly FD, Sinclair AJ, Mann NJ, Turner AH, Abedin L, Li D. A stearic acid-rich diet improves thrombogenic and atherogenic risk factor profiles in healthy males. Eur J Clin Nutr 2001; 55:88-96. [PMID: 11305631 DOI: 10.1038/sj.ejcn.1601122] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To determine whether healthy males who consumed increased amounts of dietary stearic acid compared with increased dietary palmitic acid exhibited any changes in their platelet aggregability, platelet fatty acid profiles, platelet morphology, or haemostatic factors. DESIGN A randomized cross-over dietary intervention. SUBJECTS AND INTERVENTIONS Thirteen free-living healthy males consumed two experimental diets for 4 weeks with a 7 week washout between the two dietary periods. The diets consisted of approximately 30% of energy as fat (66% of which was the treatment fat) providing approximately 6.6% of energy as stearic acid (diet S) or approximately 7.8% of energy as palmitic acid (diet P). On days 0 and 28 of each dietary period, blood samples were collected and anthropometric and physiological measurements were recorded. RESULTS Stearic acid was increased significantly in platelet phospholipids on diet S (by 22%), while on diet P palmitic acid levels in platelet phospholipids also increased significantly (8%). Mean platelet volume, coagulation factor FVII activity and plasma lipid concentrations were significantly decreased on diet S, while platelet aggregation was significantly increased on diet P. CONCLUSION Results from this study indicate that stearic acid (19g/day) in the diet has beneficial effects on thrombogenic and atherogenic risk factors in males. The food industry might wish to consider the enrichment of foods with stearic acid in place of palmitic acid and trans fatty acids.
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Affiliation(s)
- F D Kelly
- Department of Food Science, RMIT University, Victoria, Melbourne, Australia
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Affiliation(s)
- F D Kelly
- Department of Food Science, RMIT University, VIC, Australia
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