scholarly journals Ontogenetic braincase development in Psittacosaurus lujiatunensis (Dinosauria: Ceratopsia) using micro-computed tomography

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7217 ◽  
Author(s):  
Claire M. Bullar ◽  
Qi Zhao ◽  
Michael J. Benton ◽  
Michael J. Ryan
Keyword(s):  
Computed Tomography ◽  
Semicircular Canal ◽  
Morphological Changes ◽  
Relative Reduction ◽  
Growth Stages ◽  
Ontogenetic Changes ◽  
Micro Computed Tomography ◽  
Horizontal Semicircular Canal ◽  
Computed Tomography Scans ◽  
Key Events

Ontogenetic sequences are relatively rare among dinosaurs, with Ceratopsia being one of the better represented clades, and especially among geologically earlier forms, such as Psittacosaurus. Psittacosaurus is a small, bipedal basal ceratopsian abundant in the Lower Cretaceous deposits of Asia, whose cranial and endocranial morphology has been well studied, but only cursory details have been published on the bones surrounding the brain. Using reconstructions created from micro-computed tomography scans of well-preserved skulls from the Barremian–Aptian Yixian Formation, China, we document morphological changes in the braincase of Psittacosaurus lujiatunensis through three growth stages, hatchling, juvenile, and adult, thus providing the first detailed study of ceratopsian braincase morphology through ontogeny. Notable ontogenetic changes in the braincase of P. lujiatunensis include a dramatic relative reduction in size of the supraoccipital, an increase in the lateral expansion of the paroccipital processes and a decrease in the angle between the lateral semicircular canal and the palatal plane. These ontogenetic morphological changes in the braincase relate to expansion of the cranium and brain through growth, as well as reflecting the switch from quadrupedal juveniles to bipedal adults as documented in the changing orientation of the horizontal semicircular canal through ontogeny. Recognition of these patterns in a basal ceratopsian has implications for understanding key events in later ceratopsian evolution, such as the development of the parieto-squamosal frill in derived neoceratopsians.

scholarly journals Aspects of the gorgonopsian paleobiology: insights from the basicranium, occiput, osseous labyrinth and neuroanatomy of the immature gorgonopsian skull of Aloposaurus gracilis (Therapsida: Theriodontia: Gorgonopsia)

2016 ◽  
Author(s):  
Ricardo M Araujo ◽  
Vincent Fernandez ◽  
Michael J Polcyn ◽  
Jörg Fröbisch ◽  
Rui M.S. Martins
Keyword(s):  
Computed Tomography ◽  
Semicircular Canal ◽  
Phase Contrast ◽  
Cranial Nerves ◽  
Brain Anatomy ◽  
Micro Computed Tomography ◽  
Horizontal Semicircular Canal ◽  
Head Posture ◽  
The Past ◽  
The Brain

Synapsida, the clade including therapsids and thus also mammals, is one of the two major branches of amniotes. Organismal design, with modularity as a concept, offers insights into the evolution of therapsids, a group that experienced profound anatomical transformations throughout the past 270Ma, eventually leading to the evolution of the mammalian bauplan. However, the anatomy of some therapsid groups remains obscure. Gorgonopsian braincase anatomy remains poorly known, and aspects of their brain anatomy, cranial nerves and vasculature, osseous labyrinth persist unknown. By using propagation phase contrast synchrotron micro-computed tomography, we scanned GPIT/RE/7124, a specimen previously reported as Aloposaurus gracilis. We explored the anatomy of the braincase and rendered the anatomy of the various skull cavities. Notably, we found that there is a separate ossification between what was previously referred as the “parasphenoid” and the basioccipital. This element is reinterpreted as a posterior ossification of the basisphenoid, the basi-postsphenoid. Additionally the previously called “parasphenoid” is in fact the co-ossification of the dermal parasphenoid and the endochondral basi-presphenoid. The anatomy of the osseous labyrinth is rendered in detail, revealing a unique discoid morphology of the horizontal semicircular canal, rather than toroidal, probably due to architectural contraints of the ossification of the opisthotic and supraoccipital. In addition, the orientation of the horizontal semicircular canal suggests an anteriorly tilted alert head posture. The morphology of the brain endocast is in accordance with the more reptilian endocast shape of other non-mammaliaform neotherapsids.

scholarly journals A redescription of the Late Jurassic (Tithonian) turtle Uluops uluops and a new phylogenetic hypothesis of Paracryptodira

2021 ◽  
Vol 140 (1) ◽  
Author(s):  
Yann Rollot ◽  
Serjoscha W. Evers ◽  
Walter G. Joyce
Keyword(s):  
Computed Tomography ◽  
Phylogenetic Analysis ◽  
Late Jurassic ◽  
Internal Carotid ◽  
Circulation System ◽  
Phylogenetic Hypothesis ◽  
Micro Computed Tomography ◽  
Future Studies ◽  
Computed Tomography Scans ◽  
Palatine Artery

AbstractWe study the Late Jurassic (Tithonian) turtle Uluops uluops using micro-computed tomography scans to investigate the cranial anatomy of paracryptodires, and provide new insights into the evolution of the internal carotid artery and facial nerve systems, as well as the phylogenetic relationships of this group. We demonstrate the presence of a canalis caroticus lateralis in Uluops uluops, the only pleurosternid for which a palatine artery canal can be confidently identified. Our phylogenetic analysis retrieves Uluops uluops as the earliest branching pleurosternid, Helochelydridae within Pleurosternidae, and Compsemydidae including Kallokibotion bajazidi within Baenidae, which suggests at least two independent losses of the palatine artery within paracryptodires. We expect future studies will provide additional insights into the evolution of the circulation system of paracryptodires, as well as clarifying relationships along the turtle stem.

The incidence of tympanogenic labyrinthitis ossificans

2014 ◽  
Vol 128 (7) ◽  
pp. 618-620 ◽  
Author(s):  
H-Y Lin ◽  
Y-K Fan ◽  
K-C Wu ◽  
M-T Shu ◽  
C-C Yang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Head And Neck Cancer ◽  
Cochlear Implants ◽  
Semicircular Canal ◽  
Lateral Semicircular Canal ◽  
Posterior Semicircular Canal ◽  
High Resolution Computed Tomography ◽  
Labyrinthitis Ossificans ◽  
Computed Tomography Scans ◽  
History Of

AbstractObjective:To estimate the incidence of tympanogenic labyrinthitis ossificans.Methods:The records of patients treated with mastoidectomy for various tympanogenic aetiologies from January 2007 to December 2011 were retrospectively reviewed. Patients whose high-resolution computed tomography scans showed evidence of labyrinthine calcification of the temporal bone were enrolled. Patients with a history of head and neck cancer, meningitis, and otosclerosis, and patients with cochlear implants, were excluded from this study.Results:A total of 195 patients were enrolled in this study; 4 of the patients presented with calcification in the inner ear. Therefore, the incidence of tympanogenic labyrinthitis ossification was 2 per cent. The computed tomography findings revealed: (1) cochlear calcifications of the basal and middle turn in two patients; and (2) vestibular, superior semicircular canal, posterior semicircular canal and lateral semicircular canal calcification in one, four, three and two patients, respectively.Conclusion:The incidence of tympanogenic labyrinthitis ossification in patients who had undergone a mastoidectomy was 2 per cent.

scholarly journals A dataset comprising four micro-computed tomography scans of freshly fixed and museum earthworm specimens

GigaScience ◽  
2014 ◽  
Vol 3 (1) ◽  
Author(s):  
Jennifer Lenihan ◽  
Sebastian Kvist ◽  
Rosa Fernández ◽  
Gonzalo Giribet ◽  
Alexander Ziegler
Keyword(s):  
Computed Tomography ◽  
Micro Computed Tomography ◽  
Computed Tomography Scans

scholarly journals Volumetric analysis of the cranial and nasal cavity from micro-computed tomography scans in the rabbit

2020 ◽  
Vol 79 (2) ◽  
pp. 333-338
Author(s):  
C. Bakıcı ◽  
R. O. Akgun ◽  
O. Ekım ◽  
C. Soydal ◽  
C. Oto
Keyword(s):  
Computed Tomography ◽  
Nasal Cavity ◽  
Volumetric Analysis ◽  
Micro Computed Tomography ◽  
Computed Tomography Scans

scholarly journals The five digits of the giraffe metatarsal

2020 ◽  
Vol 131 (3) ◽  
pp. 699-705
Author(s):  
Laurel R Yohe ◽  
Nikos Solounias
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Fossil Record ◽  
The Other ◽  
Micro Computed Tomography ◽  
Common Assumption ◽  
Internal Morphology ◽  
Computed Tomography Scans ◽  
The Common ◽  
Taxonomic Groups

Abstract Evolution has shaped the limbs of hoofed animals in specific ways. In artiodactyls, it is the common assumption that the metatarsal is composed of the fusion of digits III and IV, whereas the other three digits have been lost or are highly reduced. However, evidence from the fossil record and internal morphology of the metatarsal challenges these assumptions. Furthermore, only a few taxonomic groups have been analysed. In giraffes, we discovered that all five digits are present in the adult metatarsal and are highly fused and modified rather than lost. We examined high-resolution micro-computed tomography scans of the metatarsals of two mid and late Miocene giraffid fossils and the extant giraffe and okapi. In all the Giraffidae analysed, we found a combination of four morphologies: (1) four articular facets; (2) four or, in most cases, five separate medullary cavities internally; (3) a clear, small digit I; and (4) in the two fossil taxa of unknown genus, the presence of external elongated grooves where the fusions of digits II and V have taken place. Giraffa and Okapia, the extant Giraffidae, show a difference from all the extinct taxa in having more flattened digits tightly packed together, suggesting convergent highly fused digits despite divergent ecologies and locomotion. These discoveries provide evidence that enhances our understanding of how bones fuse and call into question current hypotheses of digit loss.

scholarly journals Aspects of gorgonopsian paleobiology and evolution: insights from the basicranium, occiput, osseous labyrinth, vasculature, and neuroanatomy

2017 ◽  
Author(s):  
Ricardo M Araujo ◽  
Vincent Fernandez ◽  
Michael J Polcyn ◽  
Jörg Fröbisch ◽  
Rui M.S. Martins
Keyword(s):  
Semicircular Canal ◽  
Phase Contrast ◽  
Cranial Nerves ◽  
Detailed Examination ◽  
Micro Computed Tomography ◽  
Horizontal Semicircular Canal ◽  
The Past ◽  
Architectural Constraints ◽  
The Brain ◽  
Immature Specimen

Synapsida, the clade including therapsids and thus also mammals, is one of the two major branches of amniotes. Organismal design, with modularity as a concept, offers insights into the evolution of therapsids, a group that experienced profound anatomical transformations throughout the past 270Ma, eventually leading to the evolution of the mammalian bauplan. However, the anatomy of some therapsid groups remains obscure. Gorgonopsian braincase anatomy is poorly known and many anatomical aspects of the brain, cranial nerves, vasculature, and osseous labyrinth, remain unclear. We analyzed two gorgonopsian specimens, GPIT/RE/7124 and GPIT/RE/7119, using propagation phase contrast synchrotron micro-computed tomography. The lack of fusion between many basicranial and occipital bones in the immature specimen GPIT/RE/7124 allowed us to reconstruct its anatomy and ontogenetic sequence in comparison with the mature GPIT/RE/7119. We examined the braincase and rendered various skull cavities. Notably, there is a separate ossification between what was previously referred to as the “parasphenoid” and the basioccipital. We reinterpreted this element as a posterior ossification of the basisphenoid: the basipostsphenoid. Moreover, the “parasphenoid” is a co-ossification of the dermal parasphenoid and the endochondral basipresphenoid. Our detailed examination of the osseous labyrinth reveals a unique discoid, rather than toroidal, morphology of the horizontal semicircular canal that probably results from architectural constraints of the opisthotic and supraoccipital ossifications. In addition, the orientation of the horizontal semicircular canal suggests that gorgonopsians had an anteriorly tilted alert head posture. The morphology of the brain endocast is in accordance with the more reptilian endocast shape of other non-mammaliaform neotherapsids.

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