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Ksepka DT, Balanoff AM, Smith NA, Bever GS, Bhullar BAS, Bourdon E, Braun EL, Burleigh JG, Clarke JA, Colbert MW, Corfield JR, Degrange FJ, De Pietri VL, Early CM, Field DJ, Gignac PM, Gold MEL, Kimball RT, Kawabe S, Lefebvre L, Marugán-Lobón J, Mongle CS, Morhardt A, Norell MA, Ridgely RC, Rothman RS, Scofield RP, Tambussi CP, Torres CR, van Tuinen M, Walsh SA, Watanabe A, Witmer LM, Wright AK, Zanno LE, Jarvis ED, Smaers JB. Tempo and Pattern of Avian Brain Size Evolution. Curr Biol 2020; 30:2026-2036.e3. [DOI: 10.1016/j.cub.2020.03.060] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 02/05/2020] [Accepted: 03/23/2020] [Indexed: 11/25/2022]
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Abstract
Background In comparative neurobiology, major transitions in behavior are thought to be associated with proportional size changes in brain regions. Bird-line theropod dinosaurs underwent a drastic locomotory shift from terrestrial to volant forms, accompanied by a suite of well-documented postcranial adaptations. To elucidate the potential impact of this locomotor shift on neuroanatomy, we first tested for a correlation between loss of flight in extant birds and whether the brain morphology of these birds resembles that of their flightless, non-avian dinosaurian ancestors. We constructed virtual endocasts of the braincase for 80 individuals of non-avian and avian theropods, including 25 flying and 19 flightless species of crown group birds. The endocasts were analyzed using a three-dimensional (3-D) geometric morphometric approach to assess changes in brain shape along the dinosaur-bird transition and secondary losses of flight in crown-group birds (Aves). Results While non-avian dinosaurs and crown-group birds are clearly distinct in endocranial shape, volant and flightless birds overlap considerably in brain morphology. Phylogenetically informed analyses show that locomotory mode does not significantly account for neuroanatomical variation in crown-group birds. Linear discriminant analysis (LDA) also indicates poor predictive power of neuroanatomical shape for inferring locomotory mode. Given current sampling, Archaeopteryx, typically considered the oldest known bird, is inferred to be terrestrial based on its endocranial morphology. Conclusion The results demonstrate that loss of flight does not correlate with an appreciable amount of neuroanatomical changes across Aves, but rather is partially constrained due to phylogenetic inertia, evident from sister taxa having similarly shaped endocasts. Although the present study does not explicitly test whether endocranial changes along the dinosaur-bird transition are due to the acquisition of powered flight, the prominent relative expansion of the cerebrum, in areas associated with flight-related cognitive capacity, suggests that the acquisition of flight may have been an important initial driver of brain shape evolution in theropods. Electronic supplementary material The online version of this article (10.1186/s12862-018-1312-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Maria Eugenia Leone Gold
- Biology Department, Suffolk University, Boston, MA, 02108, USA. .,Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, 11779, USA. .,Division of Paleontology, American Museum of Natural History, New York, NY, 10024, USA.
| | - Akinobu Watanabe
- Division of Paleontology, American Museum of Natural History, New York, NY, 10024, USA.,Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, 11568, USA.,Life Sciences Department Vertebrates Division, Natural History Museum, London, SW7 5BD, UK
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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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Gold MEL, Bourdon E, Norell MA. The first endocast of the extinct dodo (Raphus cucullatus) and an anatomical comparison amongst close relatives (Aves, Columbiformes). Zool J Linn Soc 2016. [DOI: 10.1111/zoj.12388] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Maria Eugenia Leone Gold
- Richard Gilder Graduate School; American Museum of Natural History; Central Park West at 79th Street New York NY 10024 USA
- Division of Paleontology; American Museum of Natural History; Central Park West at 79th Street New York NY 10024 USA
- Department of Anatomical Sciences; Stony Brook University; Health Sciences Center; Stony Brook NY 11794 USA
| | - Estelle Bourdon
- Section of Biosystematics; Natural History Museum of Denmark; University of Copenhagen; Universitetsparken 15 2100 Copenhagen Denmark
| | - Mark A. Norell
- Richard Gilder Graduate School; American Museum of Natural History; Central Park West at 79th Street New York NY 10024 USA
- Division of Paleontology; American Museum of Natural History; Central Park West at 79th Street New York NY 10024 USA
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Watanabe A, Eugenia Leone Gold M, Brusatte SL, Benson RBJ, Choiniere J, Davidson A, Norell MA. Vertebral Pneumaticity in the Ornithomimosaur Archaeornithomimus (Dinosauria: Theropoda) Revealed by Computed Tomography Imaging and Reappraisal of Axial Pneumaticity in Ornithomimosauria. PLoS One 2015; 10:e0145168. [PMID: 26682888 PMCID: PMC4684312 DOI: 10.1371/journal.pone.0145168] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [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: 07/24/2015] [Accepted: 11/30/2015] [Indexed: 11/19/2022] Open
Abstract
Among extant vertebrates, pneumatization of postcranial bones is unique to birds, with few known exceptions in other groups. Through reduction in bone mass, this feature is thought to benefit flight capacity in modern birds, but its prevalence in non-avian dinosaurs of variable sizes has generated competing hypotheses on the initial adaptive significance of postcranial pneumaticity. To better understand the evolutionary history of postcranial pneumaticity, studies have surveyed its distribution among non-avian dinosaurs. Nevertheless, the degree of pneumaticity in the basal coelurosaurian group Ornithomimosauria remains poorly known, despite their potential to greatly enhance our understanding of the early evolution of pneumatic bones along the lineage leading to birds. Historically, the identification of postcranial pneumaticity in non-avian dinosaurs has been based on examination of external morphology, and few studies thus far have focused on the internal architecture of pneumatic structures inside the bones. Here, we describe the vertebral pneumaticity of the ornithomimosaur Archaeornithomimus with the aid of X-ray computed tomography (CT) imaging. Complementary examination of external and internal osteology reveals (1) highly pneumatized cervical vertebrae with an elaborate configuration of interconnected chambers within the neural arch and the centrum; (2) anterior dorsal vertebrae with pneumatic chambers inside the neural arch; (3) apneumatic sacral vertebrae; and (4) a subset of proximal caudal vertebrae with limited pneumatic invasion into the neural arch. Comparisons with other theropod dinosaurs suggest that ornithomimosaurs primitively exhibited a plesiomorphic theropod condition for axial pneumaticity that was extended among later taxa, such as Archaeornithomimus and large bodied Deinocheirus. This finding corroborates the notion that evolutionary increases in vertebral pneumaticity occurred in parallel among independent lineages of bird-line archosaurs. Beyond providing a comprehensive view of vertebral pneumaticity in a non-avian coelurosaur, this study demonstrates the utility and need of CT imaging for further clarifying the early evolutionary history of postcranial pneumaticity.
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Affiliation(s)
- Akinobu Watanabe
- Division of Paleontology, American Museum of Natural History, New York, New York, United States of America
- Richard Gilder Graduate School, American Museum of Natural History, New York, New York, United States of America
| | - Maria Eugenia Leone Gold
- Division of Paleontology, American Museum of Natural History, New York, New York, United States of America
- Richard Gilder Graduate School, American Museum of Natural History, New York, New York, United States of America
| | | | - Roger B. J. Benson
- Department of Earth Sciences, University of Oxford, Oxford, United Kingdom
- Evolutionary Studies Institute and DST/NRF Centre of Excellence in Palaeosciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Jonah Choiniere
- Evolutionary Studies Institute and DST/NRF Centre of Excellence in Palaeosciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Amy Davidson
- Division of Paleontology, American Museum of Natural History, New York, New York, United States of America
| | - Mark A. Norell
- Division of Paleontology, American Museum of Natural History, New York, New York, United States of America
- Richard Gilder Graduate School, American Museum of Natural History, New York, New York, United States of America
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Gold MEL, Brochu CA, Norell MA. An expanded combined evidence approach to the Gavialis problem using geometric morphometric data from crocodylian braincases and Eustachian systems. PLoS One 2014; 9:e105793. [PMID: 25198124 PMCID: PMC4157744 DOI: 10.1371/journal.pone.0105793] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [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: 03/14/2014] [Accepted: 07/24/2014] [Indexed: 11/19/2022] Open
Abstract
The phylogenetic position of the Indian gharial (Gavialis gangeticus) is disputed--morphological characters place Gavialis as the sister to all other extant crocodylians, whereas molecular and combined analyses find Gavialis and the false gharial (Tomistoma schlegelii) to be sister taxa. Geometric morphometric techniques have only begun to be applied to this issue, but most of these studies have focused on the exterior of the skull. The braincase has provided useful phylogenetic information for basal crurotarsans, but has not been explored for the crown group. The Eustachian system is thought to vary phylogenetically in Crocodylia, but has not been analytically tested. To determine if gross morphology of the crocodylian braincase proves informative to the relationships of Gavialis and Tomistoma, we used two- and three-dimensional geometric morphometric approaches. Internal braincase images were obtained using high-resolution computerized tomography scans. A principal components analysis identified that the first component axis was primarily associated with size and did not show groupings that divide the specimens by phylogenetic affinity. Sliding semi-landmarks and a relative warp analysis indicate that a unique Eustachian morphology separates Gavialis from other extant members of Crocodylia. Ontogenetic expansion of the braincase results in a more dorsoventrally elongate median Eustachian canal. Changes in the shape of the Eustachian system do provide phylogenetic distinctions between major crocodylian clades. Each morphometric dataset, consisting of continuous morphological characters, was added independently to a combined cladistic analysis of discrete morphological and molecular characters. The braincase data alone produced a clade that included crocodylids and Gavialis, whereas the Eustachian data resulted in Gavialis being considered a basally divergent lineage. When each morphometric dataset was used in a combined analysis with discrete morphological and molecular characters, it generated a tree that matched the topology of the molecular phylogeny of Crocodylia.
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Affiliation(s)
- Maria Eugenia Leone Gold
- Richard Gilder Graduate School, American Museum of Natural History, New York, New York, United States of America
- Division of Paleontology, American Museum of Natural History, New York, New York, United States of America
| | - Christopher A. Brochu
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, Iowa, United States of America
| | - Mark A. Norell
- Richard Gilder Graduate School, American Museum of Natural History, New York, New York, United States of America
- Division of Paleontology, American Museum of Natural History, New York, New York, United States of America
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Gold MEL, Brusatte SL, Norell MA. The Cranial Pneumatic Sinuses of the TyrannosauridAlioramus(Dinosauria: Theropoda) and the Evolution of Cranial Pneumaticity in Theropod Dinosaurs. American Museum Novitates 2013. [DOI: 10.1206/3790.1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [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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