1
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Straight PJ, Gignac PM, Kuenzel WJ. A histological and diceCT-derived 3D reconstruction of the avian visual thalamofugal pathway. Sci Rep 2024; 14:8447. [PMID: 38600121 PMCID: PMC11006926 DOI: 10.1038/s41598-024-58788-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 04/03/2024] [Indexed: 04/12/2024] Open
Abstract
Amniotes feature two principal visual processing systems: the tectofugal and thalamofugal pathways. In most mammals, the thalamofugal pathway predominates, routing retinal afferents through the dorsolateral geniculate complex to the visual cortex. In most birds, the thalamofugal pathway often plays the lesser role with retinal afferents projecting to the principal optic thalami, a complex of several nuclei that resides in the dorsal thalamus. This thalamic complex sends projections to a forebrain structure called the Wulst, the terminus of the thalamofugal visual system. The thalamofugal pathway in birds serves many functions such as pattern discrimination, spatial memory, and navigation/migration. A comprehensive analysis of avian species has unveiled diverse subdivisions within the thalamic and forebrain structures, contingent on species, age, and techniques utilized. In this study, we documented the thalamofugal system in three dimensions by integrating histological and contrast-enhanced computed tomography imaging of the avian brain. Sections of two-week-old chick brains were cut in either coronal, sagittal, or horizontal planes and stained with Nissl and either Gallyas silver or Luxol Fast Blue. The thalamic principal optic complex and pallial Wulst were subdivided on the basis of cell and fiber density. Additionally, we utilized the technique of diffusible iodine-based contrast-enhanced computed tomography (diceCT) on a 5-week-old chick brain, and right eyeball. By merging diceCT data, stained histological sections, and information from the existing literature, a comprehensive three-dimensional model of the avian thalamofugal pathway was constructed. The use of a 3D model provides a clearer understanding of the structural and spatial organization of the thalamofugal system. The ability to integrate histochemical sections with diceCT 3D modeling is critical to better understanding the anatomical and physiologic organization of complex pathways such as the thalamofugal visual system.
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Affiliation(s)
- Parker J Straight
- Poultry Science Department, University of Arkansas, Fayetteville, AR, USA.
| | - Paul M Gignac
- Cellular and Molecular Medicine Department, University of Arizona Health Sciences, Tucson, AZ, USA
- MicroCT Imaging Consortium for Research and Outreach, University of Arkansas, Fayetteville, AR, USA
| | - Wayne J Kuenzel
- Poultry Science Department, University of Arkansas, Fayetteville, AR, USA
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2
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Gray JA, Gignac PM, Stanley EL. The first full body diffusible iodine-based contrast-enhanced computed tomography dataset and teaching materials for a member of the Testudines. Anat Rec (Hoboken) 2024; 307:535-548. [PMID: 37409685 DOI: 10.1002/ar.25282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/08/2023] [Accepted: 06/14/2023] [Indexed: 07/07/2023]
Abstract
Diffusible iodine-based contrast-enhanced Computed Tomography (diceCT) is now a widely used technique for imaging metazoan soft anatomy. Turtles present a particular challenge for anatomists; gross dissection is inherently destructive and irreversible, whereas their near complete shell of bony plates, covered with keratinous scutes, presents a barrier for iodine diffusion and significantly increases contrast-enhanced CT preparation time. Consequently, a complete dataset visualizing the internal soft anatomy of turtles at high resolution and in three dimensions has not yet been successfully achieved. Here we outline a novel method that augments traditional diceCT preparation with an iodine injection technique to acquire the first full body contrast-enhanced dataset for the Testudines. We show this approach to be an effective method of staining the soft tissues inside the shell. The resulting datasets were processed to produce anatomical 3D models that can be used in teaching and research. As diceCT becomes a widely employed method for nondestructively documenting the internal soft anatomy of alcohol preserved museum specimens, we hope that methods applicable to the more challenging of these, such as turtles, will contribute toward the growing stock of digital anatomy in online repositories.
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Affiliation(s)
- Jaimi A Gray
- Florida Museum of Natural History, Gainesville, Florida, USA
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3
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Straight PJ, Gignac PM, Kuenzel WJ. Mapping the avian visual tectofugal pathway using 3D reconstruction. J Comp Neurol 2024; 532:e25558. [PMID: 38047431 DOI: 10.1002/cne.25558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/19/2023] [Accepted: 10/17/2023] [Indexed: 12/05/2023]
Abstract
Image processing in amniotes is usually accomplished by the thalamofugal and/or tectofugal visual systems. In laterally eyed birds, the tectofugal system dominates with functions such as color and motion processing, spatial orientation, stimulus identification, and localization. This makes it a critical system for complex avian behavior. Here, the brains of chicks, Gallus gallus, were used to produce serial brain sections in either coronal, sagittal, or horizontal planes and stained with either Nissl and Gallyas silver myelin or Luxol fast blue stain and cresyl echt violet (CEV). The emerging techniques of diffusible iodine-based contrast-enhanced computed tomography (diceCT) coupled with serial histochemistry in three planes were used to generate a comprehensive three-dimensional (3D) model of the avian tectofugal visual system. This enabled the 3D reconstruction of tectofugal circuits, including the three primary neuronal projections. Specifically, major components of the system included four regions of the retina, layers of the optic tectum, subdivisions of the nucleus rotundus in the thalamus, the entopallium in the forebrain, and supplementary components connecting into or out of this major avian visual sensory system. The resulting 3D model enabled a better understanding of the structural components and connectivity of this complex system by providing a complete spatial organization that occupied several distinct brain regions. We demonstrate how pairing diceCT with traditional histochemistry is an effective means to improve the understanding of, and thereby should generate insights into, anatomical and functional properties of complicated neural pathways, and we recommend this approach to clarify enigmatic properties of these pathways.
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Affiliation(s)
- Parker J Straight
- Poultry Science Department, University of Arkansas, Fayetteville, Arkansas, USA
| | - Paul M Gignac
- Cellular and Molecular Medicine Department, University of Arizona Health Sciences, Tucson, Arizona, USA
- Anatomy and Cell Biology Department, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA
| | - Wayne J Kuenzel
- Poultry Science Department, University of Arkansas, Fayetteville, Arkansas, USA
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4
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Balanoff A, Ferrer E, Saleh L, Gignac PM, Gold MEL, Marugán-Lobón J, Norell M, Ouellette D, Salerno M, Watanabe A, Wei S, Bever G, Vaska P. Quantitative functional imaging of the pigeon brain: implications for the evolution of avian powered flight. Proc Biol Sci 2024; 291:20232172. [PMID: 38290541 PMCID: PMC10827418 DOI: 10.1098/rspb.2023.2172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 01/03/2024] [Indexed: 02/01/2024] Open
Abstract
The evolution of flight is a rare event in vertebrate history, and one that demands functional integration across multiple anatomical/physiological systems. The neuroanatomical basis for such integration and the role that brain evolution assumes in behavioural transformations remain poorly understood. We make progress by (i) generating a positron emission tomography (PET)-based map of brain activity for pigeons during rest and flight, (ii) using these maps in a functional analysis of the brain during flight, and (iii) interpreting these data within a macroevolutionary context shaped by non-avian dinosaurs. Although neural activity is generally conserved from rest to flight, we found significant increases in the cerebellum as a whole and optic flow pathways. Conserved activity suggests processing of self-movement and image stabilization are critical when a bird takes to the air, while increased visual and cerebellar activity reflects the importance of integrating multimodal sensory information for flight-related movements. A derived cerebellar capability likely arose at the base of maniraptoran dinosaurs, where volumetric expansion and possible folding directly preceded paravian flight. These data represent an important step toward establishing how the brain of modern birds supports their unique behavioural repertoire and provide novel insights into the neurobiology of the bird-like dinosaurs that first achieved powered flight.
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Affiliation(s)
- Amy Balanoff
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD 21218, USA
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
| | - Elizabeth Ferrer
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
- Samuel Merritt University, Oakland, CA 94609, USA
| | - Lemise Saleh
- Department of Biomedical Engineering and Radiology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Paul M. Gignac
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
- Department of Cellular and Molecular Medicine, University of Arizona College of Medicine, Tucson, AZ 85724, USA
| | - M. Eugenia L. Gold
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
- Department of Biology, Suffolk University, Boston, MA 02108, USA
| | - Jesús Marugán-Lobón
- Unidad de Paleontología, Departamento Biología, Universidad Autónoma de Madrid, 28049 Cantoblanco (Madrid), Spain
| | - Mark Norell
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
| | | | - Michael Salerno
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, 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
| | - Shouyi Wei
- Department of Physics, New York Proton Center, New York, NY 10035, USA
| | - Gabriel Bever
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
| | - Paul Vaska
- Department of Biomedical Engineering and Radiology, Stony Brook University, Stony Brook, NY 11794, USA
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5
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Plateau O, Green TL, Gignac PM, Foth C. Comparative digital reconstruction of Pica pica and Struthio camelus and their cranial suture ontogenies. Anat Rec (Hoboken) 2024; 307:5-48. [PMID: 37338258 DOI: 10.1002/ar.25275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 05/25/2023] [Accepted: 05/26/2023] [Indexed: 06/21/2023]
Abstract
To date, several studies describe post-hatching ontogenetic variation in birds; however, none of these studies document and compare ontogenetic variation of the entire skull in multiple avian species. Therefore, we studied ontogenetic skull variation of two bird species with very different ecologies, Pica pica, and Struthio camelus, using μCT based 3D reconstructions. For each specimen, we performed bone-by-bone segmentation in order to visualize and describe the morphological variation of each bone during ontogeny and estimated the average sutural closure of the skulls to identify different ontogenetic stages. Although bone fusion of P. pica occurs more rapidly than that of S. camelus the general sequence of bone fusion follows a similar trend from posterior to anterior, but a more detailed analysis reveals some interspecific variation in the fusion patterns. Although growth persists over a longer period in S. camelus than in P. pica and adults of the former species are significantly larger, the skull of the most mature S. camelus is still less fused than that of P. pica. Different growth and fusion patterns of the two species indicate that the interspecific ontogenetic variation could be related to heterochronic developments. Nevertheless, this hypothesis needs to be tested in a broader phylogenetic framework in order to detect the evolutionary direction of the potential heterochronic transformations.
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Affiliation(s)
- Olivia Plateau
- Department of Geosciences, University of Fribourg, Fribourg, Switzerland
- Department of Earth Sciences, University of Cambridge, Cambridge, UK
| | - Todd L Green
- Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York, USA
| | - Paul M Gignac
- Department of Cellular & Molecular Medicine, University of Arizona College of Medicine, Tucson, Arizona, USA
| | - Christian Foth
- Department of Geosciences, University of Fribourg, Fribourg, Switzerland
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6
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Watanabe A, Marshall SS, Gignac PM. Dumbbell-shaped brains of Polish crested chickens as a model system for the evolution of novel brain morphologies. J Anat 2023; 243:421-430. [PMID: 37165612 PMCID: PMC10439378 DOI: 10.1111/joa.13883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 03/28/2023] [Accepted: 04/27/2023] [Indexed: 05/12/2023] Open
Abstract
The evolutionary history of vertebrates is replete with emergence of novel brain morphologies, including the origin of the human brain. Existing model organisms and toolkits for investigating drivers of neuroanatomical innovations have largely proceeded on mammals. As such, a compelling non-mammalian model system would facilitate our understanding of how unique brain morphologies evolve across vertebrates. Here, we present the domestic chicken breed, white crested Polish chickens, as an avian model for investigating how novel brain morphologies originate. Most notably, these crested chickens exhibit cerebral herniation from anterodorsal displacement of the telencephalon, which results in a prominent protuberance on the dorsal aspect of the skull. We use a high-density geometric morphometric approach on cephalic endocasts to characterize their brain morphology. Compared with standard white Leghorn chickens (WLCs) and modern avian diversity, the results demonstrate that crested chickens possess a highly variable and unique overall brain configuration. Proportional sizes of neuroanatomical regions are within the observed range of extant birds sampled in this study, but Polish chickens differ from WLCs in possessing a relatively larger cerebrum and smaller cerebellum and medulla. Given their accessibility, phylogenetic proximity, and unique neuroanatomy, we propose that crested breeds, combined with standard chickens, form a promising comparative system for investigating the emergence of novel brain morphologies.
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Affiliation(s)
- Akinobu Watanabe
- Department of AnatomyNew York Institute of Technology College of Osteopathic MedicineOld WestburyNew YorkUSA
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNew YorkUSA
- Department of Life SciencesNatural History MuseumLondonUK
| | - Sylvia S. Marshall
- Department of AnatomyNew York Institute of Technology College of Osteopathic MedicineOld WestburyNew YorkUSA
| | - Paul M. Gignac
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNew YorkUSA
- Department of Cellular and Molecular MedicineUniversity of Arizona College of MedicineTucsonArizonaUSA
- MicroCT Imaging Consortium for Research and OutreachUniversity of ArkansasFayettevilleArkansasUSA
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7
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Feldman KM, O'Keefe YA, Gignac PM, O'Brien HD. Highest resolution microCT scan of the human brainstem reveals putative anatomical basis for infrequency of medial medullary syndrome. Neuroimage Clin 2022; 36:103272. [PMID: 36451373 PMCID: PMC9723294 DOI: 10.1016/j.nicl.2022.103272] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 07/13/2022] [Revised: 11/01/2022] [Accepted: 11/17/2022] [Indexed: 11/19/2022]
Abstract
Ischemic strokes affecting the medial medulla are exceedingly rare. The anatomical basis for the relative infrequency of this stroke syndrome has been largely uninvestigated due to historically coarse MRI and CT scan resolution. We capture and digitally dissect the highest-ever-resolution diffusible iodine-based contrast-enhanced CT (diceCT) scanned images of a cadaveric brainstem to map arterial territories implicated in medial medullary infarctions. 3D reconstructions show that within the anterior spinal artery territory previously implicated in medial medullary syndrome (MMS), there are numerous, small sulcal artery branches perforating the medulla within the anterior median fissure. These branches proceed in parallel through the anteroposterior depth of the medulla as expected; however, we also identify a network of intraparenchymal, rostrocaudal anastomoses between these sulcal perforating branches. This network of intraparenchymal sulcal artery anastomoses has never been described and may provide a significant collateral supply of oxygenated blood flow throughout the medial medulla. By ramifying deeper tissues, these anastomoses can help explain the infrequency of MMS.
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Affiliation(s)
- Kaylea M. Feldman
- Oklahoma State University Center for Health Sciences, Department of Anatomy and Cell Biology, 1111 W 17th Street, Tulsa, OK 74107, USA,Corresponding authors at: 1501 N. Campbell Avenue, PO Box 245044, Tucson, AZ 85724-5044, USA (H. O’Brien).
| | - Yasmin A. O'Keefe
- Ascension St. John Medical Center, Department of Neurology/Neurocritical Care, 2100 S Wheeling Ave, Tulsa, OK 74104, USA
| | - Paul M. Gignac
- Oklahoma State University Center for Health Sciences, Department of Anatomy and Cell Biology, 1111 W 17th Street, Tulsa, OK 74107, USA,University of Arizona, Department of Cellular and Molecular Medicine, 1501 N. Campbell Avenue, PO Box 245044, Tucson, AZ 85724, USA
| | - Haley D. O'Brien
- Oklahoma State University Center for Health Sciences, Department of Anatomy and Cell Biology, 1111 W 17th Street, Tulsa, OK 74107, USA,University of Arizona, Department of Cellular and Molecular Medicine, 1501 N. Campbell Avenue, PO Box 245044, Tucson, AZ 85724, USA,Corresponding authors at: 1501 N. Campbell Avenue, PO Box 245044, Tucson, AZ 85724-5044, USA (H. O’Brien).
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8
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Green TL, Kay DI, Gignac PM. Intraspecific variation and directional casque asymmetry in adult southern cassowaries (
Casuarius casuarius
). J Anat 2022; 241:951-965. [PMID: 35933695 PMCID: PMC9482693 DOI: 10.1111/joa.13733] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 06/17/2022] [Accepted: 07/18/2022] [Indexed: 11/29/2022] Open
Abstract
The cranial casques of modern cassowaries (Casuarius) have long intrigued researchers; however, in‐depth studies regarding their morphological variation are scarce. Through visual inspection, it has been recognized that casque variability exists between conspecifics. Understanding casque variation has both evolutionary and ecological importance. Although hypothesized to be targeted by selection, intraspecific casque variation has not been quantified previously. Through a large sample of C. casuarius (n = 103), we compared casque shape (lateral and rostral views) between sexes and between individuals from non‐overlapping geographical regions using two‐dimensional (2D) geometric morphometrics. We found no statistically significant differences between the casque shape of females and males and few substantial shape differences between individuals from different geographic areas. Much of the intraspecific variation within C. casuarius is due to casque asymmetries (77.5% rightward deviating, 20.7% leftward deviating, and 1.8% non‐deviating from the midline; n = 111), which explain the high variability of southern cassowary casque shape, particularly from the rostral aspect. Finally, we discuss how our non‐significant findings implicate social selection theory, and we identify the benefits of quantifying such variation for further elucidating casque function(s) and the social biology of cassowaries.
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Affiliation(s)
- Todd L. Green
- Department of Anatomy New York Institute of Technology College of Osteopathic Medicine Old Westbury New York USA
- Department of Anatomy and Cell Biology Oklahoma State University Center for Health Sciences Tulsa Oklahoma USA
| | - David Ian Kay
- Department of Anatomy and Cell Biology Oklahoma State University Center for Health Sciences Tulsa Oklahoma USA
| | - Paul M. Gignac
- Department of Anatomy and Cell Biology Oklahoma State University Center for Health Sciences Tulsa Oklahoma USA
- Department of Cellular and Molecular Medicine University of Arizona College of Medicine Tucson Arizona USA
- Division of Paleontology American Museum of Natural History New York New York USA
- MicroCT Imaging Consortium for Research and Outreach (MICRO) Fayetteville Arkansas USA
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9
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Feldman KM, O'Keefe Y, Gignac PM, O'Brien HD. Highest Resolution MicroCT Scan of the Human Brainstem Reveals Putative Anatomical Basis for Infrequency of Medial Medullary Syndrome. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.l7828] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kaylea M. Feldman
- College of Osteopathic MedicineOSU Center for Health SciencesTulsaOK
| | | | - Paul M. Gignac
- Anatomy & Cell BiologyOSU Center for Health SciencesTulsaOK
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10
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Green TL, Kay DI, Gignac PM. 2D Geometric Morphometric Shape Analysis of
Casuarius casuarius
(Aves: Paleognathae) Cranial Casques. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r5133] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Todd L. Green
- AnatomyNew York Institute of Technology College of Osteopathic MedicineOld WestburyNY
- Anatomy and Cell BiologyOklahoma State University Center for Health SciencesTulsaOK
| | - David I. Kay
- Anatomy and Cell BiologyOklahoma State University Center for Health SciencesTulsaOK
| | - Paul M. Gignac
- Anatomy and Cell BiologyOklahoma State University Center for Health SciencesTulsaOK
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNY
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11
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Steppan SJ, Meyer AA, Barrow LN, Alhajeri BH, S Y Al-Zaidan A, Gignac PM, Erickson GM. Phylogenetics And The Evolution Of Terrestriality In Mudskippers (Gobiidae: Oxudercinae). Mol Phylogenet Evol 2022; 169:107416. [PMID: 35032645 DOI: 10.1016/j.ympev.2022.107416] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [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: 08/05/2020] [Revised: 11/30/2021] [Accepted: 12/08/2021] [Indexed: 01/23/2023]
Abstract
The initial vertebrate conquest of land by stegocephalians (Sarcopterygia) allowed access to new resources and exploitation of untapped niches precipitating a major phylogenetic diversification. However, a paucity of fossils has left considerable uncertainties about phylogenetic relationships and the eco-morphological stages in this key transition in Earth history. Among extant actinopterygians, three genera of mudskippers (Gobiidae: Oxudercinae), Boleophthalmus, Periophthalmus and Periophthalmodon are the most terrestrialized, with vertebral, appendicular, locomotory, respiratory, and epithelial specializations enabling overland excursions up to 14 hours. Unlike early stegocephalians, the ecologies and morphologies of the 45 species of oxudercines are well known, making them viable analogs for the initial vertebrate conquest of land. Nevertheless, they have received little phylogenetic attention. We compiled the largest molecular dataset to date, with 29 oxudercine species, and 5 nuclear and mitochondrial loci. Phylogenetic and comparative analyses revealed strong support for two independent terrestrial transitions, and a complex suit of ecomorphological forms in estuarine environments. Furthermore, neither Oxudercinae nor their presumed sister-group the eel gobies (Amblyopinae, a group of elongated gobies) were monophyletic with respect to each other, requiring a merging of these two subfamilies and revealing an expansion of phenotypic variation within the "mudskipper" clade. We did not find support for the expected linear model of ecomorphological and locomotory transition from fully aquatic, to mudswimming, to pectoral-aided mudswimming, to lobe-finned terrestrial locomotion proposed by earlier morphological studies. This high degree of convergent or parallel transitions to terrestriality, and apparent divergent directions of estuarine adaptation, promises even greater potential for this clade to illuminate the conquest of land. Future work should focus on these less-studied species with "transitional" and other mud-habitat specializations to fully resolve the dynamics of this diversification.
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Affiliation(s)
- Scott J Steppan
- Department of Biological Science, 327 Stadium Dr., Florida State University, Tallahassee Florida, 32306-4295, USA.
| | - Anna A Meyer
- Department of Biological Science, 327 Stadium Dr., Florida State University, Tallahassee Florida, 32306-4295, USA
| | - Lisa N Barrow
- Department of Biological Science, 327 Stadium Dr., Florida State University, Tallahassee Florida, 32306-4295, USA; Department of Biology, University of New Mexico, Albuquerque, NM 87131-0001, USA
| | - Bader H Alhajeri
- Department of Biological Sciences, Kuwait University, Safat, 13060, Kuwait
| | | | - Paul M Gignac
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa Oklahoma 74107-1898, USA
| | - Gregory M Erickson
- Department of Biological Science, 327 Stadium Dr., Florida State University, Tallahassee Florida, 32306-4295, USA
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12
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Gignac PM, Smaers JB, O'Brien HD. Unexpected bite-force conservatism as a stable performance foundation across mesoeucrocodylian historical diversity. Anat Rec (Hoboken) 2021; 305:2823-2837. [PMID: 34555273 DOI: 10.1002/ar.24768] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 01/15/2021] [Revised: 07/07/2021] [Accepted: 08/09/2021] [Indexed: 12/29/2022]
Abstract
Effective interpretation of historical selective regimes requires comprehensive in vivo performance evaluations and well-constrained ecomorphological proxies. The feeding apparatus is a frequent target of such evolutionary studies due to a direct relationship between feeding and survivorship, and the durability of craniodental elements in the fossil record. Among vertebrates, behaviors such as bite force have been central to evaluation of clade dynamics; yet, in the absence of detailed performance studies, such evaluations can misidentify potential selective factors and their roles. Here, we combine the results of a total-clade performance study with fossil-inclusive, phylogenetically informed methods to assess bite-force proxies throughout mesoeucrocodylian evolution. Although bite-force shifts were previously thought to respond to changing rostrodental selective regimes, we find body-size dependent conservation of performance proxies throughout the history of the clade, indicating stabilizing selection for bite-force potential. Such stasis reveals that mesoeucrocodylians with dietary ecologies as disparate as herbivory and hypercarnivory maintain similar bite-force-to-body-size relationships, a pattern which contrasts the precept that vertebrate bite forces should vary most strongly by diet. Furthermore, it may signal that bite-force conservation supported mesoeucrocodylian craniodental disparity by providing a stable performance foundation for the exploration of novel ecomorphospace.
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Affiliation(s)
- Paul M Gignac
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA
| | - Jeroen B Smaers
- Department of Anthropology, Stony Brook University, Circle Road, Social & Behavioral Sciences Building, Stony Brook, New York, USA
| | - Haley D O'Brien
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA
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13
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Watanabe A, Balanoff AM, Gignac PM, Gold MEL, Norell MA. Novel neuroanatomical integration and scaling define avian brain shape evolution and development. eLife 2021; 10:68809. [PMID: 34227464 PMCID: PMC8260227 DOI: 10.7554/elife.68809] [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: 03/25/2021] [Accepted: 06/15/2021] [Indexed: 12/17/2022] Open
Abstract
How do large and unique brains evolve? Historically, comparative neuroanatomical studies have attributed the evolutionary genesis of highly encephalized brains to deviations along, as well as from, conserved scaling relationships among brain regions. However, the relative contributions of these concerted (integrated) and mosaic (modular) processes as drivers of brain evolution remain unclear, especially in non-mammalian groups. While proportional brain sizes have been the predominant metric used to characterize brain morphology to date, we perform a high-density geometric morphometric analysis on the encephalized brains of crown birds (Neornithes or Aves) compared to their stem taxa—the non-avialan coelurosaurian dinosaurs and Archaeopteryx. When analyzed together with developmental neuroanatomical data of model archosaurs (Gallus, Alligator), crown birds exhibit a distinct allometric relationship that dictates their brain evolution and development. Furthermore, analyses by neuroanatomical regions reveal that the acquisition of this derived shape-to-size scaling relationship occurred in a mosaic pattern, where the avian-grade optic lobe and cerebellum evolved first among non-avialan dinosaurs, followed by major changes to the evolutionary and developmental dynamics of cerebrum shape after the origin of Avialae. Notably, the brain of crown birds is a more integrated structure than non-avialan archosaurs, implying that diversification of brain morphologies within Neornithes proceeded in a more coordinated manner, perhaps due to spatial constraints and abbreviated growth period. Collectively, these patterns demonstrate a plurality in evolutionary processes that generate encephalized brains in archosaurs and across vertebrates.
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Affiliation(s)
- Akinobu Watanabe
- Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, United States.,Division of Paleontology, American Museum of Natural History, New York, United States.,Department of Life Sciences Vertebrates Division, Natural History Museum, London, United Kingdom
| | - Amy M Balanoff
- Division of Paleontology, American Museum of Natural History, New York, United States.,Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, United States
| | - Paul M Gignac
- Division of Paleontology, American Museum of Natural History, New York, United States.,Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, United States
| | - M Eugenia L Gold
- Division of Paleontology, American Museum of Natural History, New York, United States.,Biology Department, Suffolk University, Boston, United States
| | - Mark A Norell
- Division of Paleontology, American Museum of Natural History, New York, United States
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14
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Gignac PM, O'Brien HD, Sanchez J, Vazquez-Sanroman D. Multiscale imaging of the rat brain using an integrated diceCT and histology workflow. Brain Struct Funct 2021; 226:2153-2168. [PMID: 34173869 DOI: 10.1007/s00429-021-02316-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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] [Received: 01/19/2021] [Accepted: 06/07/2021] [Indexed: 11/27/2022]
Abstract
Advancements in tissue visualization techniques have spurred significant gains in the biomedical sciences by enabling researchers to integrate their datasets across anatomical scales. Of particular import are techniques that enable the interpolation of multiple hierarchical scales in samples taken from the same individuals. In this study, we demonstrate that two-dimensional histology techniques can be employed on neural tissues following three-dimensional diffusible iodine-based contrast-enhanced computed tomography (diceCT) without causing tissue degradation. This represents the first step toward a multiscale pipeline for brain visualization. We studied brains from adolescent male Sprague-Dawley rats, comparing experimental (diceCT-stained then de-stained) to control (without diceCT) brains to examine neural tissues for immunolabeling integrity, compare somata sizes, and distinguish neurons from glial cells within the telencephalon and diencephalon. We hypothesized that if experimental and control samples do not differ significantly in morphological cell analysis, then brain tissues are robust to the chemical, temperature, and radiation environments required for these multiple, successive imaging protocols. Visualizations for experimental brains were first captured via micro-computed tomography scanning of isolated, iodine-infused specimens. Samples were then cleared of iodine, serially sectioned, and prepared again using immunofluorescent, fluorescent, and cresyl violet labeling, followed by imaging with confocal and light microscopy, respectively. Our results show that many neural targets are resilient to diceCT imaging and compatible with downstream histological staining as part of a low-cost, multiscale brain imaging pipeline.
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Affiliation(s)
- Paul M Gignac
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK, 74107, USA
| | - Haley D O'Brien
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK, 74107, USA
| | - Jimena Sanchez
- Centro de Investigaciones Cerebrales, Universidad Veracruzana, Xalapa, Mexico
| | - Dolores Vazquez-Sanroman
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK, 74107, USA.
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15
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To KHT, O’Brien HD, Stocker MR, Gignac PM. Cranial Musculoskeletal Description of Black-Throated Finch (Aves: Passeriformes: Estrildidae) with DiceCT. Integr Org Biol 2021; 3:obab007. [PMID: 34841194 PMCID: PMC8613829 DOI: 10.1093/iob/obab007] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Synopsis Dietary requirements and acquisition strategies change throughout ontogeny across various clades of tetrapods, including birds. For example, birds hatch with combinations of various behavioral, physiological, and morphological factors that place them on an altricial-precocial spectrum. Passeriformes (=songbirds) in particular, a family constituting approximately more than half of known bird species, displays the most drastic difference between hatchling and adults in each of these aspects of their feeding biology. How the shift in dietary resource acquisition is managed during ontogeny alongside its relationship to the morphology of the feeding apparatus has been largely understudied within birds. Such efforts have been hampered partly due to the small size of many birds and the diminutive jaw musculature they employ. In this study, we used standard and diffusible iodine-based contrast-enhanced computed tomography in conjunction with digital dissection to quantify and describe the cranial musculature of the Black-throated Finch (Poephila cincta) at fledgling and adult stages. Our results reveal that in both the fledgling and the adult, cranial musculature shows clear and complex partitioning in the Musculus adductor mandibulae externus that is consistent with other families within Passeriformes. We quantified jaw-muscle sizes and found that the adult showed a decrease in muscle mass in comparison to the fledgling individual. We propose that this could be the result of low sample size or a physiological effect of parental care in Passeriformes. Our study shows that high-resolution visualization techniques are informative at revealing morphological discrepancies for studies that involve small specimens such as Passeriformes especially with careful specimen selection criteria.
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Affiliation(s)
| | - H D O’Brien
- Department of Anatomy and Cell Biology, Oklahoma State University Center
for Health Sciences, 1111 W 17th Street, Tulsa,
OK 74107, USA
| | - M R Stocker
- Department of Geosciences, Virginia Tech, Derring
Hall, 926 W Campus Dr, Blacksburg, VA 24060, USA
| | - P M Gignac
- Department of Anatomy and Cell Biology, Oklahoma State University Center
for Health Sciences, 1111 W 17th Street, Tulsa,
OK 74107, USA
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16
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Green TL, Gignac PM. Osteological description of casque ontogeny in the southern cassowary (Casuarius casuarius) using micro-CT imaging. Anat Rec (Hoboken) 2020; 304:461-479. [PMID: 32558300 DOI: 10.1002/ar.24477] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [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: 02/24/2020] [Revised: 04/23/2020] [Accepted: 05/02/2020] [Indexed: 11/06/2022]
Abstract
Extant cassowaries (Casuarius) are unique flightless birds found in the tropics of Indo-Australia. They have garnered substantial attention from anatomists with focus centered on the bony makeup and function of their conspicuous cranial casques, located dorsally above the orbits and neurocranium. The osteological patterning of the casque has been formally described previously; however, there are differing interpretations between authors. These variable descriptions suggest that an anatomical understanding of casque anatomy and its constituent elements may be enhanced by developmental studies aimed at further elucidating this bizarre structure. In the present study, we clarify casque osteology of the southern cassowary (C. casuarius) by detailing casque anatomy across an extensive growth series for the first time. We used micro-computed tomography (μCT) imaging to visualize embryonic development and post-hatching ontogeny through adulthood. We also sampled closely related emus (Dromaius novaehollandiae) and ostriches (Struthio camelus) to provide valuable comparative context. We found that southern cassowary casques are comprised of three paired (i.e., nasals, lacrimals, frontals) and two unpaired elements (i.e., mesethmoid, median casque element). Although lacrimals have rarely been considered as casque elements, the contribution to the casque structure was evident in μCT images. The median casque element has often been cited as a portion of the mesethmoid. However, through comparisons between immature C. casuarius and D. novaehollandiae, we document the median casque element as a distinct unit from the mesethmoid.
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Affiliation(s)
- Todd L Green
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA
| | - Paul M Gignac
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA.,Division of Paleontology, American Museum of Natural History, New York, New York, USA.,MicroCT Imaging Consortium for Research and Outreach, Fayetteville, Arkansas, USA
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17
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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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18
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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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19
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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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20
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Green TL, Watanabe A, Gignac PM. An Osteo‐Developmental Baseline for Cranial Casque Anatomy of Southern Cassowaries Better Informs Functional Interpretations. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.06194] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Todd L. Green
- Oklahoma State University Center for Health Sciences
| | - Akinobu Watanabe
- New York Institute of Technology College of Osteopathic Medicine
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21
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O’Brien HD, Lynch LM, Vliet KA, Brueggen J, Erickson GM, Gignac PM. Crocodylian Head Width Allometry and Phylogenetic Prediction of Body Size in Extinct Crocodyliforms. Integr Org Biol 2019; 1:obz006. [PMID: 33791523 PMCID: PMC7671145 DOI: 10.1093/iob/obz006] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Body size and body-size shifts broadly impact life-history parameters of all animals, which has made accurate body-size estimates for extinct taxa an important component of understanding their paleobiology. Among extinct crocodylians and their precursors (e.g., suchians), several methods have been developed to predict body size from suites of hard-tissue proxies. Nevertheless, many have limited applications due to the disparity of some major suchian groups and biases in the fossil record. Here, we test the utility of head width (HW) as a broadly applicable body-size estimator in living and fossil suchians. We use a dataset of sexually mature male and female individuals (n = 76) from a comprehensive sample of extant suchian species encompassing nearly all known taxa (n = 22) to develop a Bayesian phylogenetic model for predicting three conventional metrics for size: body mass, snout-vent length, and total length. We then use the model to estimate size parameters for a select series of extinct suchians with known phylogenetic affinity (Montsechosuchus, Diplocynodon, and Sarcosuchus). We then compare our results to sizes reported in the literature to exemplify the utility of our approach for a broad array of fossil suchians. Our results show that HW is highly correlated with all other metrics (all R 2≥0.85) and is commensurate with femoral dimensions for its reliably as a body-size predictor. We provide the R code in order to enable other researchers to employ the model in their own research.
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Affiliation(s)
- Haley D O’Brien
- Oklahoma State University Center for Health Sciences, 1111 West 17th Street, Tulsa, OK 74107, USA
| | - Leigha M Lynch
- Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Kent A Vliet
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - John Brueggen
- St. Augustine Alligator Farm Zoological Park, 999 Anastasia Blvd, St. Augustine, FL 32080, USA
| | - Gregory M Erickson
- Department of Biological Sciences, Florida State University, 600 West College Avenue, Tallahassee, FL 32306, USA
| | - Paul M Gignac
- Oklahoma State University Center for Health Sciences, 1111 West 17th Street, Tulsa, OK 74107, USA
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22
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Watanabe A, Gignac PM, Balanoff AM, Green TL, Kley NJ, Norell MA. Are endocasts good proxies for brain size and shape in archosaurs throughout ontogeny? J Anat 2019; 234:291-305. [PMID: 30506962 PMCID: PMC6365484 DOI: 10.1111/joa.12918] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/05/2018] [Indexed: 12/21/2022] Open
Abstract
Cranial endocasts, or the internal molds of the braincase, are a crucial correlate for investigating the neuroanatomy of extinct vertebrates and tracking brain evolution through deep time. Nevertheless, the validity of such studies pivots on the reliability of endocasts as a proxy for brain morphology. Here, we employ micro-computed tomography imaging, including diffusible iodine-based contrast-enhanced CT, and a three-dimensional geometric morphometric framework to examine both size and shape differences between brains and endocasts of two exemplar archosaur taxa - the American alligator (Alligator mississippiensis) and the domestic chicken (Gallus gallus). With ontogenetic sampling, we quantitatively evaluate how endocasts differ from brains and whether this deviation changes during development. We find strong size and shape correlations between brains and endocasts, divergent ontogenetic trends in the brain-to-endocast correspondence between alligators and chickens, and a comparable magnitude between brain-endocast shape differences and intraspecific neuroanatomical variation. The results have important implications for paleoneurological studies in archosaurs. Notably, we demonstrate that the pattern of endocranial shape variation closely reflects brain shape variation. Therefore, analyses of endocranial morphology are unlikely to generate spurious conclusions about large-scale trends in brain size and shape. To mitigate any artifacts, however, paleoneurological studies should consider the lower brain-endocast correspondence in the hindbrain relative to the forebrain; higher size and shape correspondences in chickens than alligators throughout postnatal ontogeny; artificially 'pedomorphic' shape of endocasts relative to their corresponding brains; and potential biases in both size and shape data due to the lack of control for ontogenetic stages in endocranial sampling.
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Affiliation(s)
- Akinobu Watanabe
- Department of AnatomyNew York Institute of Technology College of Osteopathic MedicineOld WestburyNYUSA
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNYUSA
- Richard Gilder Graduate SchoolAmerican Museum of Natural HistoryNew YorkNYUSA
- Department of Life Sciences Vertebrates DivisionNatural History MuseumLondonUK
| | - Paul M. Gignac
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNYUSA
- Department of Anatomy and Cell BiologyOklahoma State University Center for Health SciencesTulsaOKUSA
| | - Amy M. Balanoff
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNYUSA
- Center for Functional Anatomy and EvolutionJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Todd L. Green
- Department of Anatomy and Cell BiologyOklahoma State University Center for Health SciencesTulsaOKUSA
| | - Nathan J. Kley
- Department of Anatomical SciencesStony Brook UniversityStony BrookNYUSA
| | - Mark A. Norell
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNYUSA
- Richard Gilder Graduate SchoolAmerican Museum of Natural HistoryNew YorkNYUSA
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23
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Balanoff AM, Bever GS, Colbert MW, Clarke JA, Field DJ, Gignac PM, Ksepka DT, Ridgely RC, Smith NA, Torres CR, Walsh S, Witmer LM. Best practices for digitally constructing endocranial casts: examples from birds and their dinosaurian relatives. J Anat 2016; 229:173-90. [PMID: 26403623 PMCID: PMC4948053 DOI: 10.1111/joa.12378] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [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] [Accepted: 08/17/2015] [Indexed: 11/28/2022] Open
Abstract
The rapidly expanding interest in, and availability of, digital tomography data to visualize casts of the vertebrate endocranial cavity housing the brain (endocasts) presents new opportunities and challenges to the field of comparative neuroanatomy. The opportunities are many, ranging from the relatively rapid acquisition of data to the unprecedented ability to integrate critically important fossil taxa. The challenges consist of navigating the logistical barriers that often separate a researcher from high-quality data and minimizing the amount of non-biological variation expressed in endocasts - variation that may confound meaningful and synthetic results. Our purpose here is to outline preferred approaches for acquiring digital tomographic data, converting those data to an endocast, and making those endocasts as meaningful as possible when considered in a comparative context. This review is intended to benefit those just getting started in the field but also serves to initiate further discussion between active endocast researchers regarding the best practices for advancing the discipline. Congruent with the theme of this volume, we draw our examples from birds and the highly encephalized non-avian dinosaurs that comprise closely related outgroups along their phylogenetic stem lineage.
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Affiliation(s)
- Amy M. Balanoff
- Department of Anatomical SciencesStony Brook UniversityStony BrookNYUSA
| | - G. S. Bever
- Department of AnatomyNew York Institute of TechnologyCollege of Osteopathic MedicineOld WestburyNYUSA
| | - Matthew W. Colbert
- Department of Geological SciencesThe University of Texas at AustinAustinTXUSA
| | - Julia A. Clarke
- Department of Geological SciencesThe University of Texas at AustinAustinTXUSA
| | - Daniel J. Field
- Department of Geology and GeophysicsYale UniversityNew HavenCTUSA
| | - Paul M. Gignac
- Department of Anatomy and Cell BiologyOklahoma State University Center for Health SciencesTulsaOKUSA
| | | | - Ryan C. Ridgely
- Department of Biomedical SciencesHeritage College of Osteopathic MedicineOhio UniversityAthensOHUSA
| | - N. Adam Smith
- Department of Earth SciencesThe Field Museum of Natural HistoryChicagoILUSA
| | | | - Stig Walsh
- Department of Natural SciencesNational Museums ScotlandEdinburghUK
| | - Lawrence M. Witmer
- Department of Biomedical SciencesHeritage College of Osteopathic MedicineOhio UniversityAthensOHUSA
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Gignac PM, Santana SE. A Bigger Picture: Organismal Function at the Nexus of Development, Ecology, and Evolution: An Introduction to the Symposium. Integr Comp Biol 2016; 56:369-72. [PMID: 27413091 DOI: 10.1093/icb/icw080] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Over the past 40 years of research, two perspectives have dominated the study of ecomorphology at ontogenetic and evolutionary timescales. For key anatomical complexes (e.g., feeding apparatus, locomotor systems, sensory structures), morphological changes during ontogeny are often interpreted in functional terms and linked to their putative importance for fitness. Across larger timescales, morphological transformations in these complexes are examined through character stability or mutability during cladogenesis. Because the fittest organisms must pass through ontogenetic changes in size and shape, addressing transformations in morphology at different time scales, from life histories to macroevolution, has the potential to illuminate major factors contributing to phenotypic diversity. To date, most studies have relied on the assumption that organismal form is tightly constrained by the adult niche. Although this could be accurate for organisms that rapidly reach and spend a substantial portion of their life history at the adult phenotype (e.g., birds, mammals), it may not always hold true for species that experience substantial growth after one or more major fitness filters during their ontogeny (e.g., some fishes, reptiles). In such circumstances, examining the adult phenotype as the primary result of selective processes may be erroneous as it likely obscures the developmental configuration of morphology that was most critical to early survival. Given this discrepancy-and its potential to mislead interpretations of how selection may shape a taxon's phenotype-this symposium addresses the question: how do we identify such ontogenetic "inertia," and how do we integrate developmental information into our phylogenetic, ecological, and functional interpretations of complex phenotypes?
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Affiliation(s)
- P M Gignac
- *Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma 74107-1898, USA
| | - S E Santana
- Department of Biology and Burke Museum of Natural History and Culture, University of Washington, Seattle, Washington 98195-1800, USA
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25
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Hughes DF, Walker EM, Gignac PM, Martinez A, Negishi K, Lieb CS, Greenbaum E, Khan AM. Rescuing Perishable Neuroanatomical Information from a Threatened Biodiversity Hotspot: Remote Field Methods for Brain Tissue Preservation Validated by Cytoarchitectonic Analysis, Immunohistochemistry, and X-Ray Microcomputed Tomography. PLoS One 2016; 11:e0155824. [PMID: 27196138 PMCID: PMC4873048 DOI: 10.1371/journal.pone.0155824] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 05/04/2016] [Indexed: 11/19/2022] Open
Abstract
Biodiversity hotspots, which harbor more endemic species than elsewhere on Earth, are increasingly threatened. There is a need to accelerate collection efforts in these regions before threatened or endangered species become extinct. The diverse geographical, ecological, genetic, morphological, and behavioral data generated from the on-site collection of an individual specimen are useful for many scientific purposes. However, traditional methods for specimen preparation in the field do not permit researchers to retrieve neuroanatomical data, disregarding potentially useful data for increasing our understanding of brain diversity. These data have helped clarify brain evolution, deciphered relationships between structure and function, and revealed constraints and selective pressures that provide context about the evolution of complex behavior. Here, we report our field-testing of two commonly used laboratory-based techniques for brain preservation while on a collecting expedition in the Congo Basin and Albertine Rift, two poorly known regions associated with the Eastern Afromontane biodiversity hotspot. First, we found that transcardial perfusion fixation and long-term brain storage, conducted in remote field conditions with no access to cold storage laboratory equipment, had no observable impact on cytoarchitectural features of lizard brain tissue when compared to lizard brain tissue processed under laboratory conditions. Second, field-perfused brain tissue subjected to prolonged post-fixation remained readily compatible with subsequent immunohistochemical detection of neural antigens, with immunostaining that was comparable to that of laboratory-perfused brain tissue. Third, immersion-fixation of lizard brains, prepared under identical environmental conditions, was readily compatible with subsequent iodine-enhanced X-ray microcomputed tomography, which facilitated the non-destructive imaging of the intact brain within its skull. In summary, we have validated multiple approaches to preserving intact lizard brains in remote field conditions with limited access to supplies and a high degree of environmental exposure. This protocol should serve as a malleable framework for researchers attempting to rescue perishable and irreplaceable morphological and molecular data from regions of disappearing biodiversity. Our approach can be harnessed to extend the numbers of species being actively studied by the neuroscience community, by reducing some of the difficulty associated with acquiring brains of animal species that are not readily available in captivity.
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Affiliation(s)
- Daniel F. Hughes
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
- UTEP Systems Neuroscience Laboratory, University of Texas at El Paso, El Paso, Texas, United States of America
- UTEP Biodiversity Collections, University of Texas at El Paso, El Paso, Texas, United States of America
- Doctoral Program in Ecology & Evolutionary Biology, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Ellen M. Walker
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
- UTEP Systems Neuroscience Laboratory, University of Texas at El Paso, El Paso, Texas, United States of America
- Doctoral Program in Environmental Pathobiology, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Paul M. Gignac
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, United States of America
| | - Anais Martinez
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
- UTEP Systems Neuroscience Laboratory, University of Texas at El Paso, El Paso, Texas, United States of America
- Doctoral Program in Environmental Pathobiology, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Kenichiro Negishi
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
- UTEP Systems Neuroscience Laboratory, University of Texas at El Paso, El Paso, Texas, United States of America
- Masters Program in Biology, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Carl S. Lieb
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
- UTEP Biodiversity Collections, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Eli Greenbaum
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
- UTEP Biodiversity Collections, University of Texas at El Paso, El Paso, Texas, United States of America
- Border Biomedical Research Center, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Arshad M. Khan
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
- UTEP Systems Neuroscience Laboratory, University of Texas at El Paso, El Paso, Texas, United States of America
- Border Biomedical Research Center, University of Texas at El Paso, El Paso, Texas, United States of America
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26
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Gignac PM, Kley NJ, Clarke JA, Colbert MW, Morhardt AC, Cerio D, Cost IN, Cox PG, Daza JD, Early CM, Echols MS, Henkelman RM, Herdina AN, Holliday CM, Li Z, Mahlow K, Merchant S, Müller J, Orsbon CP, Paluh DJ, Thies ML, Tsai HP, Witmer LM. Diffusible iodine-based contrast-enhanced computed tomography (diceCT): an emerging tool for rapid, high-resolution, 3-D imaging of metazoan soft tissues. J Anat 2016; 228:889-909. [PMID: 26970556 PMCID: PMC5341577 DOI: 10.1111/joa.12449] [Citation(s) in RCA: 284] [Impact Index Per Article: 35.5] [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] [Accepted: 01/05/2016] [Indexed: 12/13/2022] Open
Abstract
Morphologists have historically had to rely on destructive procedures to visualize the three‐dimensional (3‐D) anatomy of animals. More recently, however, non‐destructive techniques have come to the forefront. These include X‐ray computed tomography (CT), which has been used most commonly to examine the mineralized, hard‐tissue anatomy of living and fossil metazoans. One relatively new and potentially transformative aspect of current CT‐based research is the use of chemical agents to render visible, and differentiate between, soft‐tissue structures in X‐ray images. Specifically, iodine has emerged as one of the most widely used of these contrast agents among animal morphologists due to its ease of handling, cost effectiveness, and differential affinities for major types of soft tissues. The rapid adoption of iodine‐based contrast agents has resulted in a proliferation of distinct specimen preparations and scanning parameter choices, as well as an increasing variety of imaging hardware and software preferences. Here we provide a critical review of the recent contributions to iodine‐based, contrast‐enhanced CT research to enable researchers just beginning to employ contrast enhancement to make sense of this complex new landscape of methodologies. We provide a detailed summary of recent case studies, assess factors that govern success at each step of the specimen storage, preparation, and imaging processes, and make recommendations for standardizing both techniques and reporting practices. Finally, we discuss potential cutting‐edge applications of diffusible iodine‐based contrast‐enhanced computed tomography (diceCT) and the issues that must still be overcome to facilitate the broader adoption of diceCT going forward.
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Affiliation(s)
- Paul M Gignac
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK, USA
| | - Nathan J Kley
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, USA
| | - Julia A Clarke
- Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA
| | - Matthew W Colbert
- Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA
| | | | - Donald Cerio
- Department of Biological Sciences, Ohio University, Athens, OH, USA
| | - Ian N Cost
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA
| | - Philip G Cox
- Department of Archaeology, University of York and Hull York Medical School, York, UK
| | - Juan D Daza
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, USA
| | | | | | - R Mark Henkelman
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - A Nele Herdina
- Department of Theoretical Biology, University of Vienna, Vienna, Austria
| | - Casey M Holliday
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA
| | - Zhiheng Li
- Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA
| | - Kristin Mahlow
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätforschung an der Humboldt-Universität zu Berlin, Berlin, Germany
| | - Samer Merchant
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT, USA
| | - Johannes Müller
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätforschung an der Humboldt-Universität zu Berlin, Berlin, Germany
| | - Courtney P Orsbon
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL, USA
| | - Daniel J Paluh
- Department of Biology, Villanova University, Villanova, PA, USA
| | - Monte L Thies
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, USA
| | - Henry P Tsai
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA.,Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA
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27
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O'Brien HD, Gignac PM, Hieronymus TL, Witmer LM. A comparison of postnatal arterial patterns in a growth series of giraffe (Artiodactyla: Giraffa camelopardalis). PeerJ 2016; 4:e1696. [PMID: 26925324 PMCID: PMC4768699 DOI: 10.7717/peerj.1696] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [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: 12/16/2015] [Accepted: 01/26/2016] [Indexed: 11/20/2022] Open
Abstract
Nearly all living artiodactyls (even-toed ungulates) possess a derived cranial arterial pattern that is highly distinctive from most other mammals. Foremost among a suite of atypical arterial configurations is the functional and anatomical replacement of the internal carotid artery with an extensive, subdural arterial meshwork called the carotid rete. This interdigitating network branches from the maxillary artery and is housed within the cavernous venous sinus. As the cavernous sinus receives cooled blood draining from the nasal mucosa, heat rapidly dissipates across the high surface area of the rete to be carried away from the brain by the venous system. This combination yields one of the most effective mechanisms of selective brain cooling. Although arterial development begins from the same embryonic scaffolding typical of mammals, possession of a rete is typically accompanied by obliteration of the internal carotid artery. Among taxa with available ontogenetic data, the point at which the internal carotid obliterates is variable throughout development. In small-bodied artiodactyls, the internal carotid typically obliterates prior to parturition, but in larger species, the vessel may remain patent for several years. In this study, we use digital anatomical data collection methods to describe the cranial arterial patterns for a growth series of giraffe (Giraffa camelopardalis), from parturition to senescence. Giraffes, in particular, have unique cardiovascular demands and adaptations owing to their exceptional body form and may not adhere to previously documented stages of cranial arterial development. We find the carotid arterial system to be conserved between developmental stages and that obliteration of the giraffe internal carotid artery occurs prior to parturition.
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Affiliation(s)
- Haley D O'Brien
- Biological Sciences, Ohio University, Athens, OH, United States; Current affiliation: Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK, United States
| | - Paul M Gignac
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences , Tulsa, OK , United States
| | - Tobin L Hieronymus
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University , Rootstown, OH , United States
| | - Lawrence M Witmer
- Department of Biomedical Sciences, Ohio University Heritage College of Osteopathic Medicine , Athens, OH , United States
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28
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Gignac PM, Kley NJ. Iodine-enhanced micro-CT imaging: Methodological refinements for the study of the soft-tissue anatomy of post-embryonic vertebrates. J Exp Zool (Mol Dev Evol ) 2014; 322:166-76. [DOI: 10.1002/jez.b.22561] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 10/29/2013] [Accepted: 01/06/2014] [Indexed: 11/10/2022]
Affiliation(s)
- Paul M. Gignac
- Department of Anatomical Sciences; Stony Brook University; Stony Brook New York
- Department of Anatomy and Cell Biology; Oklahoma State University Center for Health Sciences; Tulsa Oklahoma
| | - Nathan J. Kley
- Department of Anatomical Sciences; Stony Brook University; Stony Brook New York
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29
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Erickson GM, Gignac PM, Steppan SJ, Lappin AK, Vliet KA, Brueggen JD, Inouye BD, Kledzik D, Webb GJW. Insights into the ecology and evolutionary success of crocodilians revealed through bite-force and tooth-pressure experimentation. PLoS One 2012; 7:e31781. [PMID: 22431965 PMCID: PMC3303775 DOI: 10.1371/journal.pone.0031781] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [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: 02/22/2011] [Accepted: 01/19/2012] [Indexed: 12/14/2022] Open
Abstract
Background Crocodilians have dominated predatory niches at the water-land interface for over 85 million years. Like their ancestors, living species show substantial variation in their jaw proportions, dental form and body size. These differences are often assumed to reflect anatomical specialization related to feeding and niche occupation, but quantified data are scant. How these factors relate to biomechanical performance during feeding and their relevance to crocodilian evolutionary success are not known. Methodology/Principal Findings We measured adult bite forces and tooth pressures in all 23 extant crocodilian species and analyzed the results in ecological and phylogenetic contexts. We demonstrate that these reptiles generate the highest bite forces and tooth pressures known for any living animals. Bite forces strongly correlate with body size, and size changes are a major mechanism of feeding evolution in this group. Jaw shape demonstrates surprisingly little correlation to bite force and pressures. Bite forces can now be predicted in fossil crocodilians using the regression equations generated in this research. Conclusions/Significance Critical to crocodilian long-term success was the evolution of a high bite-force generating musculo-skeletal architecture. Once achieved, the relative force capacities of this system went essentially unmodified throughout subsequent diversification. Rampant changes in body size and concurrent changes in bite force served as a mechanism to allow access to differing prey types and sizes. Further access to the diversity of near-shore prey was gained primarily through changes in tooth pressure via the evolution of dental form and distributions of the teeth within the jaws. Rostral proportions changed substantially throughout crocodilian evolution, but not in correspondence with bite forces. The biomechanical and ecological ramifications of such changes need further examination.
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Affiliation(s)
- Gregory M Erickson
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States of America.
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Pfaller JB, Gignac PM, Erickson GM. Ontogenetic changes in jaw-muscle architecture facilitate durophagy in the turtle Sternotherus minor. J Exp Biol 2011; 214:1655-67. [DOI: 10.1242/jeb.048090] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Differential scaling of musculoskeletal traits leads to differences in performance across ontogeny and ultimately determines patterns of resource use during development. Because musculoskeletal growth of the feeding system facilitates high bite-force generation necessary to overcome the physical constraints of consuming more durable prey, durophagous taxa are well suited for investigations of the scaling relationships between musculoskeletal growth, bite-force generation and dietary ontogeny. To elucidate which biomechanical factors are responsible for allometric changes in bite force and durophagy, we developed and experimentally tested a static model of bite-force generation throughout development in the durophagous turtle Sternotherus minor. Moreover, we quantified the fracture properties of snails found in the diet to evaluate the relationship between bite force and the forces required to process durable prey. We found that (1) the static bite-force model accurately predicts the ontogenetic scaling of bite forces, (2) bite-force positive allometry is accomplished by augmenting muscle size and muscle pennation, and (3) the rupture forces of snails found in the diet show a similar scaling pattern to bite force across ontogeny. These results indicate the importance of muscle pennation for generating high bite forces while maintaining muscle size and provide empirical evidence that the allometric patterns of musculoskeletal growth in S. minor are strongly linked to the structural properties of their primary prey.
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Affiliation(s)
- Joseph B. Pfaller
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - Paul M. Gignac
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - Gregory M. Erickson
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
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