51
|
Moore AJ, Mo J, Clark JM, Xu X. Cranial anatomy of Bellusaurus sui (Dinosauria: Eusauropoda) from the Middle-Late Jurassic Shishugou Formation of northwest China and a review of sauropod cranial ontogeny. PeerJ 2018; 6:e4881. [PMID: 29868283 PMCID: PMC5985764 DOI: 10.7717/peerj.4881] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 05/10/2018] [Indexed: 11/20/2022] Open
Abstract
Bellusaurus sui is an enigmatic sauropod dinosaur from the Middle-Late Jurassic Shishugou Formation of northwest China. Bellusaurus is known from a monospecific bonebed preserving elements from more than a dozen juvenile individuals, including numerous bones of the skull, providing rare insight into the cranial anatomy of juvenile sauropods. Here, we present a comprehensive description of the cranial anatomy of Bellusaurus, supplementing the holotypic cranial material with additional elements recovered from recent joint Sino-American field expeditions. Bellusaurus is diagnosed by several unique autapomorphies, including a neurovascular foramen piercing the ascending process of the maxilla at midheight, the frontal process of the nasal extending farther posteriorly onto the frontal than the prefrontal, and U-shaped medial and lateral notches in the posterior margin of the ventral process of the squamosal. Several features identified here, including a preantorbital opening in the maxilla, a stepped dorsal margin of the vomerine process of the pterygoid, and the partitioning of the dorsal midline endocranial fossae associated with the dural venous sinuses into anterior and posterior components by a transverse ridge of the parietal, are consistent with recent phylogenetic hypotheses that recover Bellusaurus as a basal macronarian or close relative of Neosauropoda. We review the current state of knowledge of sauropod cranial ontogeny, placing several aspects of the cranial anatomy of Bellusaurus in an ontogenetic context and providing explicit hypotheses of ontogenetic transformations that can be tested by future discoveries of ontogenetic variants of sauropod skulls. While scoring ontogenetically variable characters as unknown may help to alleviate the biasing effects of ontogeny on the phylogenetic position of juvenile specimens, we caution that this approach may remove phylogenetically informative character information, and argue that inference methods that are known to be less sensitive to homoplasy than equal weights parsimony (i.e., implied weights parsimony; Bayesian approaches) should also be employed.
Collapse
Affiliation(s)
- Andrew J Moore
- Department of Biological Sciences, George Washington University, Washington, DC, USA
| | - Jinyou Mo
- Natural History Museum of Guangxi Zhuang Autonomous Region, Nanning, China
| | - James M Clark
- Department of Biological Sciences, George Washington University, Washington, DC, USA
| | - Xing Xu
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
| |
Collapse
|
52
|
Abstract
The semicircular canal (SC) system of the inner ear detects head angular accelerations and is essential for navigation and spatial awareness in vertebrates. Because the bony labyrinth encloses the membranous labyrinth SCs, it can be used as a proxy for animal behavior. The bony labyrinth of dicynodonts, a clade of herbivorous non-mammalian synapsids, has only been described in a handful of individuals and remains particularly obscure. Here we describe the bony labyrinth anatomy of three Endothiodon cf. bathystoma specimens from Mozambique based on digital reconstructions from propagation phase-contrast synchrotron micro-computed tomography. We compare these findings with the bony labyrinth anatomy of their close relative Niassodon. The bony labyrinths of Endothiodon and Niassodon are relatively similar and show only differences in the shape of the horizontal SCs and the orientation of the vertical SCs. When compared to extant mammals, Endothiodon and Niassodon have highly eccentric SCs. In addition, the Endothiodon SCs are nearly orthogonal. An eccentric and orthogonal SC morphology is consistent with a specialization in rapid head movements, which are typical of foraging or feeding behaviors. Furthermore, we estimate the body mass of these Endothiodon specimens at ~116 to 182 kg, based on the average SC radii calculated using a linear regression model optimized by the Amemiya Prediction Criterion. Our findings provide novel insights into the paleobiology of Endothiodon which are consistent with the peculiar feeding mechanism among dicynodonts presumed from their multiple postcanine toothrows.
Collapse
|
53
|
Voeten DFAE, Reich T, Araújo R, Scheyer TM. Synchrotron microtomography of a Nothosaurus marchicus skull informs on nothosaurian physiology and neurosensory adaptations in early Sauropterygia. PLoS One 2018; 13:e0188509. [PMID: 29298295 PMCID: PMC5751976 DOI: 10.1371/journal.pone.0188509] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 11/08/2017] [Indexed: 02/06/2023] Open
Abstract
Nothosaurs form a subclade of the secondarily marine Sauropterygia that was well represented in late Early to early Late Triassic marine ecosystems. Here we present and discuss the internal skull anatomy of the small piscivorous nothosaur Nothosaurus marchicus from coastal to shallow marine Lower Muschelkalk deposits (Anisian) of Winterswijk, The Netherlands, which represents the oldest sauropterygian endocast visualized to date. The cranial endocast is only partially encapsulated by ossified braincase elements. Cranial flattening and lateral constriction by hypertrophied temporal musculature grant the brain a straight, tubular geometry that lacks particularly well-developed cerebral lobes but does potentially involve distinguishable optic lobes, suggesting vision may have represented an important sense during life. Despite large orbit size, the circuitous muscular pathway linking the basisphenoidal and orbital regions indicates poor oculomotor performance. This suggests a rather fixed ocular orientation, although eye placement and neck manoeuvrability could have enabled binocular if not stereoscopic vision. The proportionally large dorsal projection of the braincase endocast towards the well-developed pineal foramen advocates substantial dependence on the corresponding pineal system in vivo. Structures corroborating keen olfactory or acoustic senses were not identified. The likely atrophied vomeronasal organ argues against the presence of a forked tongue in Nothosaurus, and the relative positioning of external and internal nares contrasts respiratory configurations proposed for pistosauroid sauropterygians. The antorbital domain furthermore accommodates a putative rostral sensory plexus and pronounced lateral nasal glands that were likely exapted as salt glands. Previously proposed nothosaurian 'foramina eustachii' arose from architectural constraints on braincase development rather than representing functional foramina. Several modifications to brain shape and accessory organs were achieved through heterochronic development of the cranium, particularly the braincase. In summary, the cranium of Nothosaurus marchicus reflects important physiological and neurosensory adaptations that enabled the group's explosive invasion of shallow marine habitats in the late Early Triassic.
Collapse
Affiliation(s)
- Dennis F. A. E. Voeten
- European Synchrotron Radiation Facility, Grenoble, France
- Department of Zoology and Laboratory of Ornithology, Palacký University, Olomouc, Czech Republic
| | - Tobias Reich
- University of Zurich, Palaeontological Institute and Museum, Zurich, Switzerland
| | - Ricardo Araújo
- Institute for Plasma Research and Nuclear Fusion, Technical University of Lisbon, Lisbon, Portugal
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
- Institute of Evolutionary Sciences, University of Montpellier 2, Montpellier, France
| | - Torsten M. Scheyer
- University of Zurich, Palaeontological Institute and Museum, Zurich, Switzerland
| |
Collapse
|
54
|
Sales MAF, Schultz CL. Spinosaur taxonomy and evolution of craniodental features: Evidence from Brazil. PLoS One 2017; 12:e0187070. [PMID: 29107966 PMCID: PMC5673194 DOI: 10.1371/journal.pone.0187070] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 10/12/2017] [Indexed: 12/03/2022] Open
Abstract
Fossil sites from Brazil have yielded specimens of spinosaurid theropods, among which the most informative include the cranial remains of Irritator, Angaturama, and Oxalaia. In this work some of their craniodental features are reinterpreted, providing new data for taxonomic and evolutionary issues concerning this particular clade of dinosaurs. The mesial-most tooth of the left maxilla of the holotype of Irritator is regarded as representing the third tooth position, which is also preserved in the holotype of Angaturama. Thus, both specimens cannot belong to the same individual, contrary to previous assumptions, although they could have been the same taxon. In addition, the position of the external nares of Irritator is more comparable to those of Baryonyx and Suchomimus instead of other spinosaurine spinosaurids. In fact, with regards to some craniodental features, Brazilian taxa represent intermediate conditions between Baryonychinae and Spinosaurinae. Such a scenario is corroborated by our cladistic results, which also leave open the possibility of the former subfamily being non-monophyletic. Furthermore, the differences between spinosaurids regarding the position and size of the external nares might be related to distinct feeding habits and degrees of reliance on olfaction. Other issues concerning the evolution and taxonomy of Spinosauridae require descriptions of additional material for their clarification.
Collapse
Affiliation(s)
- Marcos A. F. Sales
- Programa de Pós-Graduação em Geociências, Instituto de Geociências, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
- Instituto Federal de Educação, Ciência e Tecnologia do Ceará (IFCE), Fortaleza, Ceará, Brazil
| | - Cesar L. Schultz
- Programa de Pós-Graduação em Geociências, Instituto de Geociências, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
- Departamento de Paleontologia e Estratigrafia, Instituto de Geociências, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
| |
Collapse
|
55
|
Rothschild BM, Naples V. Apparent sixth sense in theropod evolution: The making of a Cretaceous weathervane. PLoS One 2017; 12:e0187064. [PMID: 29095949 PMCID: PMC5667833 DOI: 10.1371/journal.pone.0187064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 10/12/2017] [Indexed: 11/17/2022] Open
Abstract
Objective Two separate and distinctive skills are necessary to find prey: Detection of its presence and determination of its location. Surface microscopy of the dentary of albertosaurines revealed a previously undescribed sensory modification, as will be described here. While dentary “foramina” were previously thought to contain tactile sensory organs, the potential function of this theropod modification as a unique localizing system is explored in this study. Method Dentary surface perforations were examined by surface epi-illumination microscopy in tyrannosaurine and albertosaurine dinosaurs to characterize their anatomy. Fish lateral lines were examined as potentially comparable structures. Result In contrast to the subsurface vascular bifurcation noted in tyrannosaurines (which lack a lateral dentary surface groove), the area subjacent to the apertures in albertosaurine grooves has the appearance of an expanded chamber. That appearance seemed to be indistinguishable from the lateral line of fish. Conclusion Dentary groove apertures in certain tyrannosaurid lines (specifically albertosaurines) not only have a unique appearance, but one with significant functional and behavior implications. The appearance of the perforations in the dentary groove of albertosaurines mirrors that previously noted only with specialized neurologic structures accommodating derived sensory functions, as seen in the lateral line of fish. The possibility that this specialized morphology could also represent a unique function in albertosaurine theropods for interacting with the environment or facilitating prey acquisition cannot be ignored. It is suggested that these expanded chambers function in perceiving and aligning the body relative to the direction of wind, perhaps a Cretaceous analogue of the contemporary midwestern weathervane.
Collapse
Affiliation(s)
- Bruce M Rothschild
- West Virginia University College of Medicine, Department of Medicine, Morgantown, West Virginia United States of America.,Carnegie Museum, Pittsburgh, Pennsylvania, United States of America
| | - Virginia Naples
- Northern Illinois University, DeKalb, Illinois, United States of America
| |
Collapse
|
56
|
Endocast of the Late Triassic (Carnian) dinosaur Saturnalia tupiniquim: implications for the evolution of brain tissue in Sauropodomorpha. Sci Rep 2017; 7:11931. [PMID: 28931837 PMCID: PMC5607302 DOI: 10.1038/s41598-017-11737-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 08/25/2017] [Indexed: 11/22/2022] Open
Abstract
The evolutionary history of dinosaurs might date back to the first stages of the Triassic (c. 250–240 Ma), but the oldest unequivocal records of the group come from Late Triassic (Carnian – c. 230 Ma) rocks of South America. Here, we present the first braincase endocast of a Carnian dinosaur, the sauropodomorph Saturnalia tupiniquim, and provide new data regarding the evolution of the floccular and parafloccular lobe of the cerebellum (FFL), which has been extensively discussed in the field of palaeoneurology. Previous studies proposed that the development of a permanent quadrupedal stance was one of the factors leading to the volume reduction of the FFL of sauropods. However, based on the new data for S. tupiniquim we identified a first moment of FFL volume reduction in non-sauropodan Sauropodomorpha, preceding the acquisition of a fully quadrupedal stance. Analysing variations in FFL volume alongside other morphological changes in the group, we suggest that this reduction is potentially related to the adoption of a more restricted herbivore diet. In this context, the FFL of sauropods might represent a vestigial trait, retained in a reduced version from the bipedal and predatory early sauropodomorphs.
Collapse
|
57
|
Bronzati M, Rauhut OWM. Braincase redescription of Efraasia minor Huene, 1908 (Dinosauria: Sauropodomorpha) from the Late Triassic of Germany, with comments on the evolution of the sauropodomorph braincase. Zool J Linn Soc 2017. [DOI: 10.1093/zoolinnean/zlx029] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
|
58
|
Lessner EJ, Stocker MR. Archosauriform endocranial morphology and osteological evidence for semiaquatic sensory adaptations in phytosaurs. J Anat 2017; 231:655-664. [PMID: 28776670 DOI: 10.1111/joa.12668] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2017] [Indexed: 11/27/2022] Open
Abstract
The examination of endocranial data of archosauriforms has led to advances on the evolution of body size, nerve pathways, and sensory abilities. However, much of that research has focused on bird-line archosaurs, resulting in a skewed view of Archosauria. Phytosauria, a hypothesized sister taxon to or early-branching member of Archosauria, provides a potential outgroup condition. Most previous phytosaur endocranial studies were executed without the use of modern technology and focused on derived members of Phytosauria. We present a comparative CT examination of the internal cranial anatomy of Wannia scurriensis, the most basal known parasuchid phytosaur. Wannia scurriensis shows some overall similarity with extant crocodylians and derived phytosaurs in general endocranial shape, a large hypophyseal fossa, and trigeminal (CN V) innervation, but as a whole, the endocast has noticeable differences to crocodylians and other phytosaurs. The pineal region is expanded dorsally as in other phytosaurs but also laterally (previously unrecognized). CN V exits the pons in a more dorsal position than in Parasuchus hislopi, Machaeroprosopus mccauleyi, or Smilosuchus gregorii. Wannia scurriensis also exhibits a larger hypophyseal fossa relative to brain size than observed in P. hislopi or S. gregorii, which may indicate more rapid growth. The well-preserved semicircular canals have lateral canals that are angled more anteroventrally than in derived phytosaurs. Extensive facial innervation from the large CN V indicates increased rostrum sensitivity and mechanoreceptive abilities as in Alligator mississippiensis. These endocranial similarities among phytosaurs and with Alligator indicate conserved ecological and functional results of an aquatic lifestyle, and highlight a need for further exploration of endocranial anatomy among Archosauriformes.
Collapse
Affiliation(s)
- Emily J Lessner
- Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.,Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Michelle R Stocker
- Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| |
Collapse
|
59
|
Brasier MD, Norman DB, Liu AG, Cotton LJ, Hiscocks JEH, Garwood RJ, Antcliffe JB, Wacey D. Remarkable preservation of brain tissues in an Early Cretaceous iguanodontian dinosaur. ACTA ACUST UNITED AC 2016. [DOI: 10.1144/sp448.3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractIt has become accepted in recent years that the fossil record can preserve labile tissues. We report here the highly detailed mineralization of soft tissues associated with a naturally occurring brain endocast of an iguanodontian dinosaur found in c. 133 Ma fluvial sediments of the Wealden at Bexhill, Sussex, UK. Moulding of the braincase wall and the mineral replacement of the adjacent brain tissues by phosphates and carbonates allowed the direct examination of petrified brain tissues. Scanning electron microscopy (SEM) imaging and computed tomography (CT) scanning revealed preservation of the tough membranes (meninges) that enveloped and supported the brain proper. Collagen strands of the meningeal layers were preserved in collophane. The blood vessels, also preserved in collophane, were either lined by, or infilled with, microcrystalline siderite. The meninges were preserved in the hindbrain region and exhibit structural similarities with those of living archosaurs. Greater definition of the forebrain (cerebrum) than the hindbrain (cerebellar and medullary regions) is consistent with the anatomical and implied behavioural complexity previously described in iguanodontian-grade ornithopods. However, we caution that the observed proximity of probable cortical layers to the braincase walls probably resulted from the settling of brain tissues against the roof of the braincase after inversion of the skull during decay and burial.Supplementary material: Information regarding associated fossil material, and additional images, can be found at https://doi.org/10.6084/m9.figshare.c.3519984
Collapse
Affiliation(s)
- Martin D. Brasier
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| | - David B. Norman
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
| | - Alexander G. Liu
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Laura J. Cotton
- School of Biological Sciences, The University of Hong Kong, Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong SAR, China
| | | | - Russell J. Garwood
- School of Earth and Environmental Sciences, University of Manchester, Manchester M13 9PL, UK
- Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Jonathan B. Antcliffe
- Institute of Earth Sciences, University of Lausanne, 1015 Lausanne, Switzerland
- Department of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK
- Oxford University Museum of Natural History, Parks Road, Oxford OX1 3PW, UK
| | - David Wacey
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
- Centre for Microscopy Characterisation and Analysis, and Australian Research Council Centre of Excellence for Core to Crust Fluid Systems, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| |
Collapse
|
60
|
Carr CE, Christensen-Dalsgaard J, Bierman H. Coupled ears in lizards and crocodilians. BIOLOGICAL CYBERNETICS 2016; 110:291-302. [PMID: 27734148 PMCID: PMC6003244 DOI: 10.1007/s00422-016-0698-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 09/17/2016] [Indexed: 05/22/2023]
Abstract
Lizard ears are coupled across the pharynx, and are very directional. In consequence all auditory responses should be directional, without a requirement for computation of sound source location. Crocodilian ears are connected through sinuses, and thus less tightly coupled. Coupling may improve the processing of low-frequency directional signals, while higher frequency signals appear to be progressively uncoupled. In both lizards and crocodilians, the increased directionality of the coupled ears leads to an effectively larger head and larger physiological range of ITDs. This increased physiological range is reviewed in the light of current theories of sound localization.
Collapse
Affiliation(s)
- Catherine E Carr
- Department of Biology, University of Maryland College Park, College Park, MD, 20742, USA.
| | | | - Hilary Bierman
- Department of Biology, University of Maryland College Park, College Park, MD, 20742, USA
| |
Collapse
|
61
|
Brusatte SL, Muir A, Young MT, Walsh S, Steel L, Witmer LM. The Braincase and Neurosensory Anatomy of an Early Jurassic Marine Crocodylomorph: Implications for Crocodylian Sinus Evolution and Sensory Transitions. Anat Rec (Hoboken) 2016; 299:1511-1530. [DOI: 10.1002/ar.23462] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/28/2016] [Accepted: 06/07/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Stephen L. Brusatte
- School of GeoSciencesUniversity of Edinburgh, Grant InstituteJames Hutton RoadEdinburgh ScotlandEH9 3FE United Kingdom
- National Museums ScotlandChambers StreetEdinburgh ScotlandEH1 1JF United Kingdom
| | - Amy Muir
- School of GeoSciencesUniversity of Edinburgh, Grant InstituteJames Hutton RoadEdinburgh ScotlandEH9 3FE United Kingdom
| | - Mark T. Young
- School of GeoSciencesUniversity of Edinburgh, Grant InstituteJames Hutton RoadEdinburgh ScotlandEH9 3FE United Kingdom
| | - Stig Walsh
- School of GeoSciencesUniversity of Edinburgh, Grant InstituteJames Hutton RoadEdinburgh ScotlandEH9 3FE United Kingdom
- National Museums ScotlandChambers StreetEdinburgh ScotlandEH1 1JF United Kingdom
| | - Lorna Steel
- Department of Earth SciencesNatural History MuseumCromwell RoadLondon EnglandSW7 5BD United Kingdom
| | - Lawrence M. Witmer
- Department of Biomedical Sciences Heritage College of Osteopathic MedicineOhio UniversityAthens Ohio
| |
Collapse
|
62
|
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] [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.
Collapse
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
| |
Collapse
|
63
|
Lautenschlager S, Butler RJ. Neural and endocranial anatomy of Triassic phytosaurian reptiles and convergence with fossil and modern crocodylians. PeerJ 2016; 4:e2251. [PMID: 27547557 PMCID: PMC4963226 DOI: 10.7717/peerj.2251] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 06/22/2016] [Indexed: 12/04/2022] Open
Abstract
Phytosaurs are a clade of large, carnivorous pseudosuchian archosaurs from the Late Triassic with a near cosmopolitan distribution. Their superficial resemblance to longirostrine (long-snouted) crocodylians, such as gharials, has often been used in the past to infer ecological and behavioural convergence between the two groups. Although more than thirty species of phytosaur are currently recognised, little is known about the endocranial anatomy of this clade. Here, we describe the endocranial anatomy (including the brain, inner ear, neurovascular structures and sinus systems) of the two non-mystriosuchine phytosaurs Parasuchus angustifrons (=“Paleorhinus angustifrons”) and Ebrachosuchus neukami from the Late Triassic of Germany based on digital reconstructions. Results show that the endocasts of both taxa are very similar to each other in their rostrocaudally elongate morphology, with long olfactory tracts, weakly demarcated cerebral regions and dorsoventrally short endosseous labyrinths. In addition, several sinuses, including large antorbital sinuses and prominent dural venous sinuses, were reconstructed. Comparisons with the endocranial anatomy of derived phytosaurs indicate that Phytosauria is united by the presence of elongate olfactory tracts and longitudinally arranged brain architecture—characters which are also shared with Crocodyliformes. However, a substantial morphological variability is observed in the cephalic and pontine flexure and the presence of a pineal organ across the different phytosaur species. These results suggest that the endocranial anatomy in Phytosauria generally follows a plesiomorphic pattern, with moderate variation within the clade likely resulting from divergent sensory and behavioural adaptations.
Collapse
Affiliation(s)
| | - Richard J Butler
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
| |
Collapse
|
64
|
Sobral G, Sookias RB, Bhullar BAS, Smith R, Butler RJ, Müller J. New information on the braincase and inner ear of Euparkeria capensis Broom: implications for diapsid and archosaur evolution. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160072. [PMID: 27493766 PMCID: PMC4968458 DOI: 10.1098/rsos.160072] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/10/2016] [Indexed: 05/27/2023]
Abstract
Since its discovery, Euparkeria capensis has been a key taxon for understanding the early evolution of archosaurs. The braincase of Euparkeria was described based on a single specimen, but much uncertainty remained. For the first time, all available braincase material of Euparkeria is re-examined using micro-computed tomography scanning. Contrary to previous work, the parabasisphenoid does not form the posterior border of the fenestra ovalis in lateral view, but it does bear a dorsal projection that forms the anteroventral half of the fenestra. No bone pneumatization was found, but the lateral depression of the parabasisphenoid may have been pneumatic. We propose that the lateral depression likely corresponds to the anterior tympanic recess present in crown archosaurs. The presence of a laterosphenoid is confirmed for Euparkeria. It largely conforms to the crocodilian condition, but shows some features which make it more similar to the avemetatarsalian laterosphenoid. The cochlea of Euparkeria is elongated, forming a deep cochlear recess. In comparison with other basal archosauromorphs, the metotic foramen is much enlarged and regionalized into vagus and recessus scalae tympani areas, indicating an increase in its pressure-relief mechanism. The anterior semicircular canal is extended and corresponds to an enlarged floccular fossa. These aspects of the braincase morphology may be related to the development of a more upright posture and active lifestyle. They also indicate further adaptations of the hearing system of Euparkeria to terrestriality.
Collapse
Affiliation(s)
- Gabriela Sobral
- Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
- Departamento de Geologia e Paleontologia, Museu Nacional do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- Museum für Naturkunde Berlin, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
| | - Roland B. Sookias
- Museum für Naturkunde Berlin, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
- GeoBio-Center, Ludwig-Maximilians-Universität München, München, Germany
| | - Bhart-Anjan S. Bhullar
- Department of Geology and Geophysics and Peabody Museum of Natural History, Yale University, New Haven, CT, USA
| | - Roger Smith
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
- Iziko South African Museum, Cape Town, South Africa
| | - Richard J. Butler
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Johannes Müller
- Museum für Naturkunde Berlin, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
| |
Collapse
|
65
|
A Basal Lithostrotian Titanosaur (Dinosauria: Sauropoda) with a Complete Skull: Implications for the Evolution and Paleobiology of Titanosauria. PLoS One 2016; 11:e0151661. [PMID: 27115989 PMCID: PMC4846048 DOI: 10.1371/journal.pone.0151661] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 03/02/2016] [Indexed: 11/19/2022] Open
Abstract
We describe Sarmientosaurus musacchioi gen. et sp. nov., a titanosaurian sauropod dinosaur from the Upper Cretaceous (Cenomanian-Turonian) Lower Member of the Bajo Barreal Formation of southern Chubut Province in central Patagonia, Argentina. The holotypic and only known specimen consists of an articulated, virtually complete skull and part of the cranial and middle cervical series. Sarmientosaurus exhibits the following distinctive features that we interpret as autapomorphies: (1) maximum diameter of orbit nearly 40% rostrocaudal length of cranium; (2) complex maxilla-lacrimal articulation, in which the lacrimal clasps the ascending ramus of the maxilla; (3) medial edge of caudal sector of maxillary ascending ramus bordering bony nasal aperture with low but distinct ridge; (4) 'tongue-like' ventral process of quadratojugal that overlaps quadrate caudally; (5) separate foramina for all three branches of the trigeminal nerve; (6) absence of median venous canal connecting infundibular region to ventral part of brainstem; (7) subvertical premaxillary, procumbent maxillary, and recumbent dentary teeth; (8) cervical vertebrae with 'strut-like' centroprezygapophyseal laminae; (9) extremely elongate and slender ossified tendon positioned ventrolateral to cervical vertebrae and ribs. The cranial endocast of Sarmientosaurus preserves some of the most complete information obtained to date regarding the brain and sensory systems of sauropods. Phylogenetic analysis recovers the new taxon as a basal member of Lithostrotia, as the most plesiomorphic titanosaurian to be preserved with a complete skull. Sarmientosaurus provides a wealth of new cranial evidence that reaffirms the close relationship of titanosaurs to Brachiosauridae. Moreover, the presence of the relatively derived lithostrotian Tapuiasaurus in Aptian deposits indicates that the new Patagonian genus represents a 'ghost lineage' with a comparatively plesiomorphic craniodental form, the evolutionary history of which is missing for at least 13 million years of the Cretaceous. The skull anatomy of Sarmientosaurus suggests that multiple titanosaurian species with dissimilar cranial structures coexisted in the early Late Cretaceous of southern South America. Furthermore, the new taxon possesses a number of distinctive morphologies-such as the ossified cervical tendon, extremely pneumatized cervical vertebrae, and a habitually downward-facing snout-that have rarely, if ever, been documented in other titanosaurs, thus broadening our understanding of the anatomical diversity of this remarkable sauropod clade. The latter two features were convergently acquired by at least one penecontemporaneous diplodocoid, and may represent mutual specializations for consuming low-growing vegetation.
Collapse
|
66
|
Paulina-Carabajal A, Lee YN, Jacobs LL. Endocranial Morphology of the Primitive Nodosaurid Dinosaur Pawpawsaurus campbelli from the Early Cretaceous of North America. PLoS One 2016; 11:e0150845. [PMID: 27007950 PMCID: PMC4805287 DOI: 10.1371/journal.pone.0150845] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 02/19/2016] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Ankylosaurs are one of the least explored clades of dinosaurs regarding endocranial anatomy, with few available descriptions of braincase anatomy and even less information on brain and inner ear morphologies. The main goal of this study is to provide a detailed description of the braincase and internal structures of the Early Cretaceous nodosaurid Pawpawsaurus campbelli, based on recently made CT scans. METHODOLOGY/PRINCIPAL FINDINGS The skull of Pawpawsaurus was CT scanned at University of Texas at Austin (UTCT). Three-dimensional models were constructed using Mimics 18.0 (Materialise). The digital data and further processed 3D models revealed inaccessible anatomic structures, allowing a detailed description of the lateral wall of the braincase (obscured by other bones in the articulated skull), and endocranial structures such as the cranial endocast, the most complete inner ear morphology for a nodosaurid, and the interpretation of the airflow system within the nasal cavities. CONSLUSIONS/SIGNIFICANCE The new information on the endocranial morphology of Pawpawsaurus adds anatomical data to the poorly understand ankylosaur paleoneurology. The new set of data has potential use not only in taxonomy and phylogeny, but also in paleobiological interpretations based on the relative development of sense organs, such as olfaction, hearing and balance.
Collapse
Affiliation(s)
- Ariana Paulina-Carabajal
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA), San Carlos de Bariloche, Argentina
- * E-mail:
| | - Yuong-Nam Lee
- School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea
| | - Louis L. Jacobs
- Roy M. Huffington Department of Earth Sciences, Southern Methodist University, Dallas, United States of America
| |
Collapse
|
67
|
New tyrannosaur from the mid-Cretaceous of Uzbekistan clarifies evolution of giant body sizes and advanced senses in tyrant dinosaurs. Proc Natl Acad Sci U S A 2016; 113:3447-52. [PMID: 26976562 DOI: 10.1073/pnas.1600140113] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tyrannosaurids--the familiar group of carnivorous dinosaurs including Tyrannosaurus and Albertosaurus--were the apex predators in continental ecosystems in Asia and North America during the latest Cretaceous (ca. 80-66 million years ago). Their colossal sizes and keen senses are considered key to their evolutionary and ecological success, but little is known about how these features developed as tyrannosaurids evolved from smaller basal tyrannosauroids that first appeared in the fossil record in the Middle Jurassic (ca. 170 million years ago). This is largely because of a frustrating 20+ million-year gap in the mid-Cretaceous fossil record, when tyrannosauroids transitioned from small-bodied hunters to gigantic apex predators but from which no diagnostic specimens are known. We describe the first distinct tyrannosauroid species from this gap, based on a highly derived braincase and a variety of other skeletal elements from the Turonian (ca. 90-92 million years ago) of Uzbekistan. This taxon is phylogenetically intermediate between the oldest basal tyrannosauroids and the latest Cretaceous forms. It had yet to develop the giant size and extensive cranial pneumaticity of T. rex and kin but does possess the highly derived brain and inner ear characteristic of the latest Cretaceous species. Tyrannosauroids apparently developed huge size rapidly during the latest Cretaceous, and their success in the top predator role may have been enabled by their brain and keen senses that first evolved at smaller body size.
Collapse
|
68
|
A bizarre theropod from the Early Cretaceous of Japan highlighting mosaic evolution among coelurosaurians. Sci Rep 2016; 6:20478. [PMID: 26908367 PMCID: PMC4763874 DOI: 10.1038/srep20478] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 01/05/2016] [Indexed: 11/12/2022] Open
Abstract
Our understanding of coelurosaurian evolution, particularly of bird origins, has been greatly improved, mainly due to numerous recently discovered fossils worldwide. Nearly all these discoveries are referable to the previously known coelurosaurian subgroups. Here, we report a new theropod, Fukuivenator paradoxus, gen. et sp. nov., based on a nearly complete specimen from the Lower Cretaceous Kitadani Formation of the Tetori Group, Fukui, Japan. While Fukuivenator possesses a large number of morphological features unknown in any other theropod, it has a combination of primitive and derived features seen in different theropod subgroups, notably dromaeosaurid dinosaurs. Computed-tomography data indicate that Fukuivenator possesses inner ears whose morphology is intermediate between those of birds and non-avian dinosaurs. Our phylogenetic analysis recovers Fukuivenator as a basally branching maniraptoran theropod, yet is unable to refer it to any known coelurosaurian subgroups. The discovery of Fukuivenator considerably increases the morphological disparity of coelurosaurian dinosaurs and highlights the high levels of homoplasy in coelurosaurian evolution.
Collapse
|
69
|
Montefeltro FC, Andrade DV, Larsson HCE. The evolution of the meatal chamber in crocodyliforms. J Anat 2016; 228:838-63. [PMID: 26843096 DOI: 10.1111/joa.12439] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2015] [Indexed: 11/27/2022] Open
Abstract
The unique outer ear of crocodylians consists of a large meatal chamber (MC) concealed by a pair of muscular earlids that shape a large part of the animal's head. This chamber is limited medially by the enlarged tympanic membrane. Yet, the anatomy of this distinctive and complex region is underexplored and its evolutionary history untraced. The osteology and soft tissues of the MC in extant crocodylians was analysed to describe it and establish osteological correlates within this region. A broad survey of the osteological correlates was conducted in major clades of fossil crocodyliforms to estimate evolutionary trends of the MC. The reorganization of the MC at the origin of crocodyliforms includes characters also present in more basal taxa such as 'sphenosuchians' as well as unique traits of crocodyliforms. Three major patterns are recognized in the MC of basal mesoeucrocodylians. The distinct 'thalattosuchian pattern' indicates that extensive modifications occurred in this clade of aquatic fossil crocodyliforms, even when multiple alternative phylogenetic positions are taken into account. Some traits already established in putative closely related clades are absent or modified in this group. The 'basal notosuchian/sebecian pattern' is widespread among basal metasuchians, and establishes for the first time characters maintained later in neosuchians and extant forms. The 'advanced notosuchian pattern' includes modifications of the MC possibly related to a terrestrial lifestyle and potentially a structure analogous to the mammalian pinna. The main variation in the MC of neosuchians is associated with the homoplastic secondary opening of the cranioquadrate passage. The inferred phylogenetic trends in the crocodyliform MC suggest the great anatomical disparity in this region followed a complex evolutionary pattern, and tympanic hearing played an important role in the origin and diversification of Crocodyliformes.
Collapse
Affiliation(s)
- Felipe C Montefeltro
- Departamento de Biologia e Zootecnia, FEIS-UNESP, Ilha Solteira, São Paulo, Brazil
| | - Denis V Andrade
- Departamento de Zoologia, UNESP, Rio Claro, São Paulo, Brazil
| | | |
Collapse
|
70
|
Sobral G, Müller J. Archosaurs and Their Kin: The Ruling Reptiles. EVOLUTION OF THE VERTEBRATE EAR 2016. [DOI: 10.1007/978-3-319-46661-3_10] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
71
|
Leahey LG, Molnar RE, Carpenter K, Witmer LM, Salisbury SW. Cranial osteology of the ankylosaurian dinosaur formerly known as Minmi sp. (Ornithischia: Thyreophora) from the Lower Cretaceous Allaru Mudstone of Richmond, Queensland, Australia. PeerJ 2015; 3:e1475. [PMID: 26664806 PMCID: PMC4675105 DOI: 10.7717/peerj.1475] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 11/16/2015] [Indexed: 11/30/2022] Open
Abstract
Minmi is the only known genus of ankylosaurian dinosaur from Australia. Seven specimens are known, all from the Lower Cretaceous of Queensland. Only two of these have been described in any detail: the holotype specimen Minmi paravertebra from the Bungil Formation near Roma, and a near complete skeleton from the Allaru Mudstone on Marathon Station near Richmond, preliminarily referred to a possible new species of Minmi. The Marathon specimen represents one of the world’s most complete ankylosaurian skeletons and the best-preserved dinosaurian fossil from eastern Gondwana. Moreover, among ankylosaurians, its skull is one of only a few in which the majority of sutures have not been obliterated by dermal ossifications or surface remodelling. Recent preparation of the Marathon specimen has revealed new details of the palate and narial regions, permitting a comprehensive description and thus providing new insights cranial osteology of a basal ankylosaurian. The skull has also undergone computed tomography, digital segmentation and 3D computer visualisation enabling the reconstruction of its nasal cavity and endocranium. The airways of the Marathon specimen are more complicated than non-ankylosaurian dinosaurs but less so than derived ankylosaurians. The cranial (brain) endocast is superficially similar to those of other ankylosaurians but is strongly divergent in many important respects. The inner ear is extremely large and unlike that of any dinosaur yet known. Based on a high number of diagnostic differences between the skull of the Marathon specimen and other ankylosaurians, we consider it prudent to assign this specimen to a new genus and species of ankylosaurian. Kunbarrasaurus ieversi gen. et sp. nov. represents the second genus of ankylosaurian from Australia and is characterised by an unusual melange of both primitive and derived characters, shedding new light on the evolution of the ankylosaurian skull.
Collapse
Affiliation(s)
- Lucy G Leahey
- School of Biological Sciences, University of Queensland , Brisbane, Queensland , Australia
| | - Ralph E Molnar
- University of California Museum of Paleontology , Berkeley, CA , USA
| | | | - Lawrence M Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University , Athens, OH , USA
| | - Steven W Salisbury
- School of Biological Sciences, University of Queensland , Brisbane, Queensland , Australia
| |
Collapse
|
72
|
Knoll F, Witmer LM, Ridgely RC, Ortega F, Sanz JL. A New Titanosaurian Braincase from the Cretaceous "Lo Hueco" Locality in Spain Sheds Light on Neuroanatomical Evolution within Titanosauria. PLoS One 2015; 10:e0138233. [PMID: 26444700 PMCID: PMC4596832 DOI: 10.1371/journal.pone.0138233] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 08/26/2015] [Indexed: 11/25/2022] Open
Abstract
Despite continuous improvements, our knowledge of the neurocranial anatomy of sauropod dinosaurs as a whole is still poor, which is especially true for titanosaurians even though their postcranial remains are common in many Upper Cretaceous sites worldwide. Here we describe a braincase from the uppermost Cretaceous locality of ‘‘Lo Hueco” in Spain that is one of the most complete titanosaurian braincases found so far in Europe. Although the titanosaurian Ampelosaurus sp. is known from the same locality, this specimen is clearly a distinct taxon and presents a number of occipital characters found in Antarctosaurus and Jainosaurus, which are approximately coeval taxa from southern Gondwana. The specimen was subjected to X-ray computed tomographic (CT) scanning, allowing the generation of 3D renderings of the endocranial cavity enclosing the brain, cranial nerves, and blood vessels, as well as the labyrinth of the inner ear. These findings add considerable knowledge to the field of sauropod paleoneuroanatomy in general and titanosaurian endocast diversity in particular. Compared with that of many sauropodomorphs, the endocast appears only slightly flexed in lateral view and bears similarities (e.g., reduction of the rostral dural expansion) with Gondwanan titanosaurians such as Jainosaurus, Bonatitan, and Antarctosaurus. The vestibular system of the inner ear is somewhat contracted (i.e., the radius of the semicircular canals is small), but less so than expected in derived titanosaurians. However, as far as the new specimen and Jainosaurus can be contrasted, and with the necessary caution due to the small sample of comparative data currently available, the two taxa appear more similar to one another in endocast morphology than to other titanosaurians. Recent phylogenetic analyses of titanosaurians have not included virtually any of the taxa under consideration here, and thus the phylogenetic position of the new Spanish titanosaurian—even its generic, let alone specific, identification—is not possible at the moment. Nevertheless, both the braincase osteology and the endocast morphology suggest that the specimen represents a derived titanosaurian that presumably branched further from the base of Lithostrotia, potentially even near Saltasauridae, comparable in evolutionary terms with Jainosaurus.
Collapse
Affiliation(s)
- Fabien Knoll
- School of Earth, Atmospheric & Environmental Sciences, University of Manchester, Manchester, United Kingdom
- School of Earth Sciences, University of Bristol, Bristol, United Kingdom
- Departamento de Paleobiología, Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain
- * E-mail:
| | - Lawrence M. Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States of America
| | - Ryan C. Ridgely
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States of America
| | - Francisco Ortega
- Departamento de Física Matemática y de Fluidos, Facultad de Ciencias, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | - Jose Luis Sanz
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| |
Collapse
|
73
|
Carr CE, Christensen-Dalsgaard J. Sound Localization Strategies in Three Predators. BRAIN, BEHAVIOR AND EVOLUTION 2015; 86:17-27. [PMID: 26398572 DOI: 10.1159/000435946] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this paper, we compare some of the neural strategies for sound localization and encoding interaural time differences (ITDs) in three predatory species of Reptilia, alligators, barn owls and geckos. Birds and crocodilians are sister groups among the extant archosaurs, while geckos are lepidosaurs. Despite the similar organization of their auditory systems, archosaurs and lizards use different strategies for encoding the ITDs that underlie localization of sound in azimuth. Barn owls encode ITD information using a place map, which is composed of neurons serving as labeled lines tuned for preferred spatial locations, while geckos may use a meter strategy or population code composed of broadly sensitive neurons that represent ITD via changes in the firing rate.
Collapse
Affiliation(s)
- Catherine E Carr
- Department of Biology, University of Maryland Center for the Comparative and Evolutionary Biology of Hearing, College Park, Md., USA
| | | |
Collapse
|
74
|
Dufeau DL, Witmer LM. Ontogeny of the Middle-Ear Air-Sinus System in Alligator mississippiensis (Archosauria: Crocodylia). PLoS One 2015; 10:e0137060. [PMID: 26398659 PMCID: PMC4580574 DOI: 10.1371/journal.pone.0137060] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 08/12/2015] [Indexed: 01/05/2023] Open
Abstract
Modern crocodylians, including Alligator mississippiensis, have a greatly elaborated system of pneumatic sinuses invading the cranium. These sinuses invade nearly all the bones of the chondrocranium and several bony elements of the splanchnocranium, but patterns of postnatal paratympanic sinus development are poorly understood and documented. Much of crocodylomorph--indeed archosaurian--evolution is characterized by the evolution of various paratympanic air sinuses, the homologies of which are poorly understood due in large part to the fact that individual sinuses tend to become confluent in adults, obscuring underlying patterns. This study seeks to explore the ontogeny of these sinuses primarily to clarify the anatomical relations of the individual sinuses before they become confluent and thus to provide the foundation for later studies testing hypotheses of homology across extant and extinct Archosauria. Ontogeny was assessed using computed tomography in a sample of 13 specimens covering an almost 19-fold increase in head size. The paratympanic sinus system comprises two major inflations of evaginated pharyngeal epithelium: the pharyngotympanic sinus, which communicates with the pharynx via the lateral (true) Eustachian tubes and forms the cavum tympanicum proprium, and the median pharyngeal sinus, which communicates with the pharynx via the median pharyngeal tube. Each of these primary inflations gives rise to a number of secondary inflations that further invade the bones of the skull. The primary sinuses and secondary diverticula are well developed in perinatal individuals of Alligator, but during ontogeny the number and relative volumes of the secondary diverticula are reduced. In addition to describing the morphological ontogeny of this sinus system, we provide some preliminary exploratory analyses of sinus function and allometry, rejecting the hypothesis that changes in the volume of the paratympanic sinuses are simply an allometric function of braincase volume, but instead support the hypothesis that these changes may be a function of the acoustic properties of the middle ear.
Collapse
Affiliation(s)
- David L. Dufeau
- Department of Biological Sciences, Ohio University, Athens, Ohio, United States of America
- * E-mail:
| | - Lawrence M. Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States of America
| |
Collapse
|
75
|
Sobral G, Sues HD, Müller J. Anatomy of the Enigmatic Reptile Elachistosuchus huenei Janensch, 1949 (Reptilia: Diapsida) from the Upper Triassic of Germany and Its Relevance for the Origin of Sauria. PLoS One 2015; 10:e0135114. [PMID: 26352985 PMCID: PMC4564268 DOI: 10.1371/journal.pone.0135114] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 07/19/2015] [Indexed: 12/03/2022] Open
Abstract
The holotype and only known specimen of the enigmatic small reptile Elachistosuchus huenei Janensch, 1949 from the Upper Triassic (Norian) Arnstadt Formation of Saxony-Anhalt (Germany) is redescribed using μCT scans of the material. This re-examination revealed new information on the morphology of this taxon, including previously unknown parts of the skeleton such as the palate, braincase, and shoulder girdle. Elachistosuchus is diagnosed especially by the presence of the posterolateral process of the frontal, the extension of the maxillary tooth row to the posterior margin of the orbit, the free posterior process of the jugal, and the notched anterior margin of the interclavicle. Phylogenetic analyses using two recently published character-taxon matrices recovered conflicting results for the phylogenetic position of Elachistosuchus-either as an archosauromorph, as a lepidosauromorph or as a more basal, non-saurian diapsid. These different placements highlight the need of a thorough revision of critical taxa and new character sets used for inferring neodiapsid relationships.
Collapse
Affiliation(s)
- Gabriela Sobral
- Museum für Naturkunde Berlin, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
| | - Hans-Dieter Sues
- Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, MRC 121, Washington, DC, United States of America
| | - Johannes Müller
- Museum für Naturkunde Berlin, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
| |
Collapse
|
76
|
Blanco A, Fortuny J, Vicente A, Luján ÀH, García-Marçà JA, Sellés AG. A new species of Allodaposuchus (Eusuchia, Crocodylia) from the Maastrichtian (Late Cretaceous) of Spain: phylogenetic and paleobiological implications. PeerJ 2015; 3:e1171. [PMID: 26339549 PMCID: PMC4558081 DOI: 10.7717/peerj.1171] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 07/20/2015] [Indexed: 11/20/2022] Open
Abstract
Background. The Late Cretaceous is a keystone period to understand the origin and early radiation of Crocodylia, the group containing all extant lineages of crocodilians. Among the taxa described from the latest Cretaceous of Europe, the genus Allodaposuchus is one of the most common but also one of the most controversial. However, because of its fragmentary record, several issues regarding its phylogenetic emplacement and its ecology remain unsolved or unknown. The discovery of a single specimen attributed to Allodaposuchus, represented by both cranial and postcranial remains, from the Casa Fabà site (Tremp Basin, NE Spain) in the lower red unit of the Tremp Fm. (early Maastrichtian, Late Cretaceous) offers a unique opportunity to deepen in the phylogenetic relationships of the group and its ecological features. Methods. The specimen is described in detail, and CT scan of the skull is performed in order to study the endocranial morphology as well as paratympanic sinuses configuration. In addition, myological and phylogenetic analyses are also carried out on the specimen for to shed light in ecological and phylogenetic issues, respectively. Results. The specimen described herein represents a new species, Allodaposuchus hulki sp. nov., closely related to the Romanian A. precedens. The CT scan of the skull revealed an unexpected paratympanic sinuses configuration. Allosaposuchus hulki exhibits an “anterodorsal tympanic sinus” not observed in any other extant or extinct crocodilian. The caudal tympanic recesses are extremely enlarged, and the expanded quadratic sinus seems to be connected to the middle-ear channel. Phylogenetic analyses confirm the emplacement of the informal taxonomic group ‘Allodaposuchia’ at the base of Crocodylia, being considered the sister group of Borealosuchus and Planocraniidae. Discussion. Although this is a preliminary hypothesis, the unique paratympanic configuration displayed by A. hulki suggests that it could possess a high-specialized auditory system. Further, the large cranial cavities could help to reduce the weight of the cranium. Concerning the postcranial skeleton, Allodaposuchus hulki shows massive and robust vertebrae and forelimb bones, suggesting it could have a bulky body. The myological study performed on the anterior limb elements supports this interpretation. In addition, several bone and muscular features seem to point at a semi-erected position of the forelimbs during terrestrial locomotion. Taking all the above results into consideration, it seems plausible to suggest that A. hulki could conduct large incursions out of the water and have a semi-terrestrial lifestyle.
Collapse
Affiliation(s)
- Alejandro Blanco
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona , Sabadell, Catalonia , Spain
| | - Josep Fortuny
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona , Sabadell, Catalonia , Spain
| | - Alba Vicente
- Departament d'Estratigrafia, Paleontologia i Geociències marines, Facultat de Geologia, Universitat de Barcelona, Carrer de Martí i Franquès s/n , Barcelona, Catalonia , Spain
| | - Àngel H Luján
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona , Sabadell, Catalonia , Spain
| | - Jordi Alexis García-Marçà
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona , Sabadell, Catalonia , Spain
| | - Albert G Sellés
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona , Sabadell, Catalonia , Spain
| |
Collapse
|
77
|
Abstract
Ornithomimosaur dinosaurs evolved lightweight, edentulous skulls that possessed keratinous rhamphothecae. Understanding the anatomy of these taxa allows for a greater understanding of “ostrich-mimic” dinosaurs and character change during theropod dinosaur evolution. However, taphonomic processes during fossilisation often distort fossil remains. Retrodeformation offers a means by which to recover a hypothesis of the original anatomy of the specimen, and 3D scanning technologies present a way to constrain and document the retrodeformation process. Using computed tomography (CT) scan data, specimen specific retrodeformations were performed on three-dimensionally preserved but taphonomically distorted skulls of the deinocheirid Garudimimus brevipesBarsbold, 1981 and the ornithomimids Struthiomimus altusLambe, 1902 and Ornithomimus edmontonicusSternberg, 1933. This allowed for a reconstruction of the adductor musculature, which was then mapped onto the crania, from which muscle mechanical advantage and bite forces were calculated pre- and post-retrodeformation. The extent of the rhamphotheca was varied in each taxon to represent morphologies found within modern Aves. Well constrained retrodeformation allows for increased confidence in anatomical and functional analysis of fossil specimens and offers an opportunity to more fully understand the soft tissue anatomy of extinct taxa.
Collapse
Affiliation(s)
- Andrew R Cuff
- School of Earth Sciences, University of Bristol , Bristol , United Kingdom
| | - Emily J Rayfield
- School of Earth Sciences, University of Bristol , Bristol , United Kingdom
| |
Collapse
|
78
|
Bourke JM, Porter WMR, Ridgely RC, Lyson TR, Schachner ER, Bell PR, Witmer LM. Breathing life into dinosaurs: tackling challenges of soft-tissue restoration and nasal airflow in extinct species. Anat Rec (Hoboken) 2015; 297:2148-86. [PMID: 25312371 DOI: 10.1002/ar.23046] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 06/25/2014] [Indexed: 11/10/2022]
Abstract
The nasal region plays a key role in sensory, thermal, and respiratory physiology, but exploring its evolution is hampered by a lack of preservation of soft-tissue structures in extinct vertebrates. As a test case, we investigated members of the "bony-headed" ornithischian dinosaur clade Pachycephalosauridae (particularly Stegoceras validum) because of their small body size (which mitigated allometric concerns) and their tendency to preserve nasal soft tissues within their hypermineralized skulls. Hypermineralization directly preserved portions of the olfactory turbinates along with an internal nasal ridge that we regard as potentially an osteological correlate for respiratory conchae. Fossil specimens were CT-scanned, and nasal cavities were segmented and restored. Soft-tissue reconstruction of the nasal capsule was functionally tested in a virtual environment using computational fluid dynamics by running air through multiple models differing in nasal soft-tissue conformation: a bony-bounded model (i.e., skull without soft tissue) and then models with soft tissues added, such as a paranasal septum, a scrolled concha, a branched concha, and a model combining the paranasal septum with a concha. Deviations in fluid flow in comparison to a phylogenetically constrained sample of extant diapsids were used as indicators of missing soft tissue. Models that restored aspects of airflow found in extant diapsids, such as appreciable airflow in the olfactory chamber, were judged as more likely. The model with a branched concha produced airflow patterns closest to those of extant diapsids. These results from both paleontological observation and airflow modeling indicate that S. validum and other pachycephalosaurids could have had both olfactory and respiratory conchae. Although respiratory conchae have been linked to endothermy, such conclusions require caution in that our re-evaluation of the reptilian nasal apparatus indicates that respiratory conchae may be more widespread than originally thought, and other functions, such as selective brain temperature regulation, could be important.
Collapse
Affiliation(s)
- Jason M Bourke
- Department of Biological Sciences, Ohio University, Athens, Ohio
| | | | | | | | | | | | | |
Collapse
|
79
|
Bierman HS, Carr CE. Sound localization in the alligator. Hear Res 2015; 329:11-20. [PMID: 26048335 DOI: 10.1016/j.heares.2015.05.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 05/12/2015] [Accepted: 05/24/2015] [Indexed: 10/23/2022]
Abstract
In early tetrapods, it is assumed that the tympana were acoustically coupled through the pharynx and therefore inherently directional, acting as pressure difference receivers. The later closure of the middle ear cavity in turtles, archosaurs, and mammals is a derived condition, and would have changed the ear by decoupling the tympana. Isolation of the middle ears would then have led to selection for structural and neural strategies to compute sound source localization in both archosaurs and mammalian ancestors. In the archosaurs (birds and crocodilians) the presence of air spaces in the skull provided connections between the ears that have been exploited to improve directional hearing, while neural circuits mediating sound localization are well developed. In this review, we will focus primarily on directional hearing in crocodilians, where vocalization and sound localization are thought to be ecologically important, and indicate important issues still awaiting resolution.
Collapse
Affiliation(s)
- Hilary S Bierman
- Center for Comparative and Evolutionary Biology of Hearing, Department of Biology, University of Maryland College Park, College Park, Maryland 20742, USA.
| | - Catherine E Carr
- Center for Comparative and Evolutionary Biology of Hearing, Department of Biology, University of Maryland College Park, College Park, Maryland 20742, USA.
| |
Collapse
|
80
|
Craniocervical myology and functional morphology of the small-headed therizinosaurian theropods Falcarius utahensis and Nothronychus mckinleyi. PLoS One 2015; 10:e0117281. [PMID: 25706764 PMCID: PMC4338109 DOI: 10.1371/journal.pone.0117281] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 12/19/2014] [Indexed: 11/19/2022] Open
Abstract
Therizinosaurs represent a highly unusual clade of herbivorous theropods from the Cretaceous of North America and Asia. Following descriptions of the basicrania of the North American therizinosaurs Falcarius utahenisis and Nothronychus mckinleyi, the craniocervical musculature in both taxa is reconstructed using Tyrannosaurus, Allosaurus, and some extant birds as models. These muscles are subdivided into functional groups as dorsiflexors, lateroflexors, and ventroflexors. Lateroflexors and dorsiflexors in Nothronychus, but not Falcarius, are reduced, from the plesiomorphic theropod condition, but are still well developed. Attachments in both genera are favorable for an increase in ventroflexion in feeding, convergent with Allosaurus fragilis. Falcarius and Nothronychus are both characterized by a flat occipital condyle, followed by centra with shallow articular facets suggesting neck function very similar to that of an ostrich Struthio camelus. Neck movement was a combined result of minimal movement between the individual cervical vertebrae.
Collapse
|
81
|
Tornadic storm avoidance behavior in breeding songbirds. Curr Biol 2014; 25:98-102. [PMID: 25532897 DOI: 10.1016/j.cub.2014.10.079] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 10/27/2014] [Accepted: 10/29/2014] [Indexed: 11/21/2022]
Abstract
Migration is a common behavior used by animals of many taxa to occupy different habitats during different periods. Migrant birds are categorized as either facultative (i.e., those that are forced to migrate by some proximal cue, often weather) or obligate (i.e., those that migrate on a regular cycle). During migration, obligate migrants can curtail or delay flights in response to inclement weather or until favorable winds prevail, and they can temporarily reorient or reverse direction when ecological or meteorological obstacles are encountered. However, it is not known whether obligate migrants undertake facultative migrations and make large-scale movements in response to proximal cues outside of their regular migration periods. Here, we present the first documentation of obligate long-distance migrant birds undertaking a facultative migration, wherein breeding golden-winged warblers (Vermivora chrysoptera) carrying light-level geolocators performed a >1,500 km 5-day circumvention of a severe tornadic storm. The birds evacuated their breeding territories >24 hr before the arrival of the storm and atmospheric variation associated with it. The probable cue, radiating >1,000 km from tornadic storms, perceived by birds and influencing bird behavior and movements, is infrasound (i.e., sound below the range of human hearing). With the predicted increase in severity and frequency of similar storms as anthropogenic climate change progresses, understanding large-scale behavioral responses of animals to such events will be an important objective of future research.
Collapse
|
82
|
Balanoff AM, Bever GS, Norell MA. Reconsidering the Avian Nature of the Oviraptorosaur Brain (Dinosauria: Theropoda). PLoS One 2014; 9:e113559. [PMID: 25494183 PMCID: PMC4262302 DOI: 10.1371/journal.pone.0113559] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 10/25/2014] [Indexed: 11/19/2022] Open
Abstract
The high degree of encephalization characterizing modern birds is the product of a long evolutionary history, our understanding of which is still largely in its infancy. Here we provide a redescription of the endocranial space of the oviraptorosaurian dinosaur Conchoraptor gracilis with the goal of assessing the hypothesis that it shares uniquely derived endocranial characters with crown-group avians. The existence of such features has implications for the transformational history of avian neuroanatomy and suggests that the oviraptorosaur radiation is a product of the immediate stem lineage of birds-after the divergence of Archaeopteryx lithographica. Results derived from an expanded comparative sample indicate that the strong endocranial similarity between Conchoraptor and modern birds largely reflects shared conservation of plesiomorphic features. The few characters that are maintained as being uniquely expressed in these two taxa are more likely products of convergence than homology but still indicate that the oviraptorosaur endocranial cavity has much to teach us about the complex history of avian brain evolution.
Collapse
Affiliation(s)
- Amy M. Balanoff
- Stony Brook University, Department of Anatomical Sciences, Stony Brook, New York, United States of America
- American Museum of Natural History, Division of Paleontology, Central Park West at 79 Street, New York, New York, United States of America
- * E-mail:
| | - G. S. Bever
- New York Institute of Technology, College of Osteopathic Medicine, Department of Anatomy, Northern Boulevard, Old Westbury, New York, United States of America
- American Museum of Natural History, Division of Paleontology, Central Park West at 79 Street, New York, New York, United States of America
| | - Mark A. Norell
- American Museum of Natural History, Division of Paleontology, Central Park West at 79 Street, New York, New York, United States of America
| |
Collapse
|
83
|
Introduction to Evolutionary Teratology, with an Application to the Forelimbs of Tyrannosauridae and Carnotaurinae (Dinosauria: Theropoda). Evol Biol 2014. [DOI: 10.1007/s11692-014-9296-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
84
|
Laaß M. Bone-conduction hearing and seismic sensitivity of the Late Permian anomodont Kawingasaurus fossilis. J Morphol 2014; 276:121-43. [PMID: 25284624 DOI: 10.1002/jmor.20325] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 07/23/2014] [Accepted: 08/09/2014] [Indexed: 11/11/2022]
Abstract
An investigation of the internal cranial anatomy of the anomodont Kawingasaurus from the Upper Permian Usili Formation in Tanzania by means of neutron tomography revealed an unusual inner and middle ear anatomy such as extraordinarily inflated vestibules, lateroventrally orientated stapes with large footplates, and a small angle between the planes of the anterior and lateral semicircular canals. The vestibule has a volume, which is about 25 times larger than the human vestibule, although Kawingasaurus has only a skull length of approximately 40 mm. Vestibule inflation and enlarged stapes footplates are thought to be functionally correlated with bone-conduction hearing; both morphologies have been observed in fossorial vertebrates using seismic signals for communication. The firmly fused triangular head with spatulate snout was probably used for digging and preadapted to seismic signal detection. The quadrate-quadratojugal complex was able to transmit sound from the articular to the stapes by small vibrations of the quadrate process, which formed a ball and socket joint with the squamosal. Mechanical considerations suggest that the ventrolaterally orientated stapes of Kawingasaurus was mechanically better suited to transmit seismic sound from the ground to the fenestra vestibuli than a horizontal orientated stapes. The low sound pressure level transformer ratio of 2-3 in Kawingasaurus points to a seismic sensitivity of the middle ear and a vestigial or reduced sensitivity to airborne sound. Three hypothetical pathways of bone conduction in Kawingasaurus are discussed: 1) sound transmission via the spatulate snout and skull roof to the otic capsules, 2) relative movements resulting from the inertia of the mandible if sound is percepted with the skull, and 3) bone conduction from the substrate via mandible, jaw articulation, and stapes to the inner ear.
Collapse
Affiliation(s)
- Michael Laaß
- Institute of Earth Sciences, Ruprecht-Karls-University of Heidelberg, Im Neuenheimer Feld 234, D-69120, Heidelberg, Germany
| |
Collapse
|
85
|
Snively E, Russell AP, Powell GL, Theodor JM, Ryan MJ. The role of the neck in the feeding behaviour of the Tyrannosauridae: inference based on kinematics and muscle function of extant avians. J Zool (1987) 2014. [DOI: 10.1111/jzo.12109] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- E. Snively
- Department of Biology; University of Wisconsin-La Crosse; La Crosse WI USA
| | - A. P. Russell
- Department of Biological Sciences; University of Calgary; Calgary AB Canada
| | - G. L. Powell
- Department of Biological Sciences; University of Calgary; Calgary AB Canada
| | - J. M. Theodor
- Department of Biological Sciences; University of Calgary; Calgary AB Canada
| | - M. J. Ryan
- Cleveland Museum of Natural History; Cleveland OH USA
| |
Collapse
|
86
|
Nomura T, Murakami Y, Gotoh H, Ono K. Reconstruction of ancestral brains: exploring the evolutionary process of encephalization in amniotes. Neurosci Res 2014; 86:25-36. [PMID: 24671134 DOI: 10.1016/j.neures.2014.03.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 02/20/2014] [Accepted: 03/03/2014] [Indexed: 11/24/2022]
Abstract
There is huge divergence in the size and complexity of vertebrate brains. Notably, mammals and birds have bigger brains than other vertebrates, largely because these animal groups established larger dorsal telencephali. Fossil evidence suggests that this anatomical trait could have evolved independently. However, recent comparative developmental analyses demonstrate surprising commonalities in neuronal subtypes among species, although this interpretation is highly controversial. In this review, we introduce intriguing evidence regarding brain evolution collected from recent studies in paleontology and developmental biology, and we discuss possible evolutionary changes in the cortical developmental programs that led to the encephalization and structural complexity of amniote brains. New research concepts and approaches will shed light on the origin and evolutionary processes of amniote brains, particularly the mammalian cerebral cortex.
Collapse
Affiliation(s)
- Tadashi Nomura
- Developmental Neurobiology, Kyoto Prefectural University of Medicine, Nishitakatsukasa-cho 13, Taishogun, Kita-ku, Kyoto 603-8334, Japan; Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
| | - Yasunori Murakami
- Graduate School of Science and Engineering, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Hitoshi Gotoh
- Developmental Neurobiology, Kyoto Prefectural University of Medicine, Nishitakatsukasa-cho 13, Taishogun, Kita-ku, Kyoto 603-8334, Japan
| | - Katsuhiko Ono
- Developmental Neurobiology, Kyoto Prefectural University of Medicine, Nishitakatsukasa-cho 13, Taishogun, Kita-ku, Kyoto 603-8334, Japan
| |
Collapse
|
87
|
Ezcurra MD. The osteology of the basal archosauromorph Tasmaniosaurus triassicus from the Lower Triassic of Tasmania, Australia. PLoS One 2014; 9:e86864. [PMID: 24497988 PMCID: PMC3907582 DOI: 10.1371/journal.pone.0086864] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 12/19/2013] [Indexed: 11/30/2022] Open
Abstract
Proterosuchidae are the most taxonomically diverse archosauromorph reptiles sampled in the immediate aftermath of the Permo-Triassic mass extinction and represent the earliest radiation of Archosauriformes (archosaurs and closely related species). Proterosuchids are potentially represented by approximately 15 nominal species collected from South Africa, China, Russia, Australia and India, but the taxonomic content of the group is currently in a state of flux because of the poor anatomic and systematic information available for several of its putative members. Here, the putative proterosuchid Tasmaniosaurus triassicus from the Lower Triassic of Hobart, Tasmania (Australia), is redescribed. The holotype and currently only known specimen includes cranial and postcranial remains and the revision of this material sheds new light on the anatomy of the animal, including new data on the cranial endocast. Several bones are re-identified or reinterpreted, contrasting with the descriptions of previous authors. The new information provided here shows that Tasmaniosaurus closely resembles the South African proterosuchid Proterosuchus, but it differed in the presence of, for example, a slightly downturned premaxilla, a shorter anterior process of maxilla, and a diamond-shaped anterior end of interclavicle. Previous claims for the presence of gut contents in the holotype of Tasmaniosaurus are considered ambiguous. The description of the cranial endocast of Tasmaniosaurus provides for the first time information about the anatomy of this region in proterosuchids. The cranial endocast preserves possibly part of the vomero-nasal ( = Jacobson's) system laterally to the olfactory bulbs. Previous claims of the absence of the vomero-nasal organs in archosaurs, which is suggested by the extant phylogenetic bracket, are questioned because its absence in both clades of extant archosaurs seems to be directly related with the independent acquisition of a non-ground living mode of life.
Collapse
Affiliation(s)
- Martín D. Ezcurra
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
- GeoBio-Center, Ludwig-Maximilian-Universität München, Munich, Germany
| |
Collapse
|
88
|
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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
89
|
Gee CT. Applying microCT and 3D visualization to Jurassic silicified conifer seed cones: A virtual advantage over thin-sectioning. APPLICATIONS IN PLANT SCIENCES 2013; 1:apps.1300039. [PMID: 25202495 PMCID: PMC4103457 DOI: 10.3732/apps.1300039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 10/01/2013] [Indexed: 05/20/2023]
Abstract
UNLABELLED PREMISE OF THE STUDY As an alternative to conventional thin-sectioning, which destroys fossil material, high-resolution X-ray computed tomography (also called microtomography or microCT) integrated with scientific visualization, three-dimensional (3D) image segmentation, size analysis, and computer animation is explored as a nondestructive method of imaging the internal anatomy of 150-million-year-old conifer seed cones from the Late Jurassic Morrison Formation, USA, and of recent and other fossil cones. • METHODS MicroCT was carried out on cones using a General Electric phoenix v|tome|x s 240D, and resulting projections were processed with visualization software to produce image stacks of serial single sections for two-dimensional (2D) visualization, 3D segmented reconstructions with targeted structures in color, and computer animations. • RESULTS If preserved in differing densities, microCT produced images of internal fossil tissues that showed important characters such as seed phyllotaxy or number of seeds per cone scale. Color segmentation of deeply embedded seeds highlighted the arrangement of seeds in spirals. MicroCT of recent cones was even more effective. • CONCLUSIONS This is the first paper on microCT integrated with 3D segmentation and computer animation applied to silicified seed cones, which resulted in excellent 2D serial sections and segmented 3D reconstructions, revealing features requisite to cone identification and understanding of strobilus construction.
Collapse
Affiliation(s)
- Carole T. Gee
- Steinmann Institute of Geology, Mineralogy, and Paleontology, Division of Paleontology, University of Bonn, Nussallee 8, 53115 Bonn, Germany
| |
Collapse
|
90
|
Marugán-Lobón J, Chiappe LM, Farke AA. The variability of inner ear orientation in saurischian dinosaurs: testing the use of semicircular canals as a reference system for comparative anatomy. PeerJ 2013; 1:e124. [PMID: 23940837 PMCID: PMC3740149 DOI: 10.7717/peerj.124] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Accepted: 07/17/2013] [Indexed: 12/26/2022] Open
Abstract
The vestibular system of the inner ear houses three semicircular canals—oriented on three nearly-orthogonal planes—that respond to angular acceleration stimuli. In recent years, the orientation of the lateral semicircular canal (LSC) has been regularly used to determine skull orientations for comparative purposes in studies of non-avian dinosaurs. Such orientations have been inferred based on fixing the LSC to a common set of coordinates (parallel to the Earth’s horizon), given that the orientation to gravity of this sensory system is assumed constant among taxa. Under this assumption, the LSC is used as a baseline (a reference system) both to estimate how the animals held their heads and to describe craniofacial variation among dinosaurs. However, the available data in living birds (extant saurischian dinosaurs) suggests that the orientation of the LSC in non-avian saurischian dinosaurs could have been very variable and taxon-specific. If such were the case, using the LSC as a comparative reference system would cause inappropriate visual perceptions of craniofacial organization, leading to significant descriptive inconsistencies among taxa. Here, we used Procrustes methods (Geometric Morphometrics), a suite of analytical tools that compares morphology on the basis of shared landmark homology, to show that the variability of LSC relative to skull landmarks is large (ca. 50°) and likely unpredictable, thus making it an inconsistent reference system for comparing and describing the skulls of saurischian (sauropodomorph and theropod) dinosaurs. In light of our results, the lateral semicircular canal is an inconsistent baseline for comparative studies of craniofacial morphology in dinosaurs.
Collapse
Affiliation(s)
- Jesús Marugán-Lobón
- Unidad de Paleontología, Dpto. Biología, Universidad Autónoma de Madrid , Cantoblanco (Madrid) , Spain ; The Dinosaur Institute, Natural History Museum of Los Angeles County , Los Angeles, CA , USA
| | | | | |
Collapse
|
91
|
Balanoff AM, Bever GS, Rowe TB, Norell MA. Evolutionary origins of the avian brain. Nature 2013; 501:93-6. [PMID: 23903660 DOI: 10.1038/nature12424] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Accepted: 06/24/2013] [Indexed: 11/09/2022]
Abstract
Features that were once considered exclusive to modern birds, such as feathers and a furcula, are now known to have first appeared in non-avian dinosaurs. However, relatively little is known of the early evolutionary history of the hyperinflated brain that distinguishes birds from other living reptiles and provides the important neurological capablities required by flight. Here we use high-resolution computed tomography to estimate and compare cranial volumes of extant birds, the early avialan Archaeopteryx lithographica, and a number of non-avian maniraptoran dinosaurs that are phylogenetically close to the origins of both Avialae and avian flight. Previous work established that avian cerebral expansion began early in theropod history and that the cranial cavity of Archaeopteryx was volumetrically intermediate between these early forms and modern birds. Our new data indicate that the relative size of the cranial cavity of Archaeopteryx is reflective of a more generalized maniraptoran volumetric signature and in several instances is actually smaller than that of other non-avian dinosaurs. Thus, bird-like encephalization indices evolved multiple times, supporting the conclusion that if Archaeopteryx had the neurological capabilities required of flight, so did at least some other non-avian maniraptorans. This is congruent with recent findings that avialans were not unique among maniraptorans in their ability to fly in some form.
Collapse
Affiliation(s)
- Amy M Balanoff
- American Museum of Natural History, Division of Paleontology, New York, New York 10024, USA.
| | | | | | | |
Collapse
|
92
|
Abstract
Feeding strategies of the large theropod, Tyrannosaurus rex, either as a predator or a scavenger, have been a topic of debate previously compromised by lack of definitive physical evidence. Tooth drag and bone puncture marks have been documented on suggested prey items, but are often difficult to attribute to a specific theropod. Further, postmortem damage cannot be distinguished from intravital occurrences, unless evidence of healing is present. Here we report definitive evidence of predation by T. rex: a tooth crown embedded in a hadrosaurid caudal centrum, surrounded by healed bone growth. This indicates that the prey escaped and lived for some time after the injury, providing direct evidence of predatory behavior by T. rex. The two traumatically fused hadrosaur vertebrae partially enclosing a T. rex tooth were discovered in the Hell Creek Formation of South Dakota.
Collapse
|
93
|
Carabajal AP, Sterli J, Müller J, Hilger A. Neuroanatomy of the marine Jurassic turtle Plesiochelys etalloni (Testudinata, Plesiochelyidae). PLoS One 2013; 8:e69264. [PMID: 23844257 PMCID: PMC3699497 DOI: 10.1371/journal.pone.0069264] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 06/06/2013] [Indexed: 11/19/2022] Open
Abstract
Turtles are one of the least explored clades regarding endocranial anatomy with few available descriptions of the brain and inner ear of extant representatives. In addition, the paleoneurology of extinct turtles is poorly known and based on only a few natural cranial endocasts. The main goal of this study is to provide for the first time a detailed description of the neuroanatomy of an extinct turtle, the Late Jurassic Plesiochelysetalloni, including internal carotid circulation, cranial endocast and inner ear, based on the first digital 3D reconstruction using micro CT scans. The general shape of the cranial endocast of P. etalloni is tubular, with poorly marked cephalic and pontine flexures. Anteriorly, the olfactory bulbs are clearly differentiated suggesting larger bulbs than in any other described extinct or extant turtle, and indicating a higher capacity of olfaction in this taxon. The morphology of the inner ear of P. etalloni is comparable to that of extant turtles and resembles those of slow-moving terrestrial vertebrates, with markedly low, short and robust semicircular canals, and a reduced lagena. In P. etalloni the arterial pattern is similar to that found in extant cryptodires, where all the internal carotid branches are protected by bone. As the knowledge of paleoneurology in turtles is scarce and the application of modern techniques such as 3D reconstructions based on CT scans is almost unexplored in this clade, we hope this paper will trigger similar investigations of this type in other turtle taxa.
Collapse
Affiliation(s)
- Ariana Paulina Carabajal
- Consejo Nacional de Investigaciones Científicas y Técnicas-Museo Carmen Funes, Neuquén, Argentina.
| | | | | | | |
Collapse
|
94
|
Lautenschlager S, Hübner T. Ontogenetic trajectories in the ornithischian endocranium. J Evol Biol 2013; 26:2044-50. [DOI: 10.1111/jeb.12181] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 04/05/2013] [Accepted: 04/09/2013] [Indexed: 11/30/2022]
Affiliation(s)
| | - T. Hübner
- Bayerische Staatssammlung für Paläontologie und Geobiology; Munich Germany
| |
Collapse
|
95
|
Bever GS, Brusatte SL, Carr TD, Xu X, Balanoff AM, Norell MA. The Braincase Anatomy of the Late Cretaceous DinosaurAlioramus(Theropoda: Tyrannosauroidea). BULLETIN OF THE AMERICAN MUSEUM OF NATURAL HISTORY 2013. [DOI: 10.1206/810.1] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
96
|
Rhinn M, Miyoshi K, Watanabe A, Kawaguchi M, Ito F, Kuratani S, Baker CV, Murakami Y, Rijli FM. Evolutionary divergence of trigeminal nerve somatotopy in amniotes. J Comp Neurol 2013; 521:1378-94. [DOI: 10.1002/cne.23236] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 07/24/2012] [Accepted: 10/02/2012] [Indexed: 11/10/2022]
|
97
|
George ID, Holliday CM. Trigeminal Nerve Morphology inAlligator mississippiensisand Its Significance for Crocodyliform Facial Sensation and Evolution. Anat Rec (Hoboken) 2013; 296:670-80. [DOI: 10.1002/ar.22666] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 06/14/2012] [Indexed: 11/08/2022]
Affiliation(s)
- Ian D. George
- Integrative Anatomy, Department of Pathology and Anatomical Sciences; University of Missouri; Columbia Missouri USA
| | - Casey M. Holliday
- Integrative Anatomy, Department of Pathology and Anatomical Sciences; University of Missouri; Columbia Missouri USA
| |
Collapse
|
98
|
Modern Imaging Techniques as a Window to Prehistoric Auditory Worlds. INSIGHTS FROM COMPARATIVE HEARING RESEARCH 2013. [DOI: 10.1007/2506_2013_32] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
99
|
Northcutt RG. Variation in Reptilian Brains and Cognition. BRAIN, BEHAVIOR AND EVOLUTION 2013; 82:45-54. [DOI: 10.1159/000351996] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
100
|
Auditory Brain Stem Processing in Reptiles and Amphibians: Roles of Coupled Ears. INSIGHTS FROM COMPARATIVE HEARING RESEARCH 2013. [DOI: 10.1007/2506_2013_24] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|