scholarly journals Lizards and snakes from the earliest Miocene of Saint-Gérand-le-Puy, France: an anatomical and histological approach of some of the oldest Neogene squamates from Europe

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Georgios L. Georgalis ◽  
Torsten M. Scheyer
Keyword(s):  
Ct Scanning ◽  
Time Interval ◽  
Micro Ct ◽  
Anatomical Structures ◽  
Postcranial Remains ◽  
Vascular Channels ◽  
Geographic Expansion ◽  
Thermoregulatory Function ◽  
New Occurrences ◽  
High Diversity

Abstract Background The earliest Miocene (Aquitanian) represents a crucial time interval in the evolution of European squamates (i.e., lizards and snakes), witnessing a high diversity of taxa, including an array of extinct forms but also representatives of extant genera. We here conduct a taxonomical survey along with a histological/microanatomical approach on new squamate remains from the earliest Miocene of Saint-Gérand-le-Puy, France, an area that has been well known for its fossil discoveries since the nineteenth century. Results We document new occurrences of taxa, among which, the lacertid Janosikia and the anguid Ophisaurus holeci, were previously unknown from France. We provide a detailed description of the anatomical structures of the various cranial and postcranial remains of lizards and snakes from Saint-Gérand-le-Puy. By applying micro-CT scanning in the most complete cranial elements of our sample, we decipher previously unknown microanatomical features. We report in detail the subsurface distribution and 3D connectivity of vascular channels in the anguid parietal. The fine meshwork of channels and cavities or sinuses in the parietal of Ophisaurus could indicate some thermoregulatory function, as it has recently been demonstrated for other vertebrate groups, providing implications for the palaeophysiology of this earliest Miocene anguine lizard. Conclusions A combination of anatomical and micro-anatomical/histological approach, aided by micro-CT scanning, enabled the documentation of these new earliest Miocene squamate remains. A distinct geographic expansion is provided for the extinct anguine Ophisaurus holeci and the lacertid Janosikia (the closest relative of the extant insular Gallotia from the Canary Islands).

Observation of the Pulp Chamber of Maxillary First Premolars: A Micro-computed Tomographic Study

2020 ◽  
Vol 16 (3) ◽  
pp. 224-230
Author(s):  
Gozde Serindere ◽  
Ceren Aktuna Belgin ◽  
Kaan Orhan
Keyword(s):  
Root Canal ◽  
Age Groups ◽  
Slice Thickness ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
Pulp Chamber ◽  
Anatomical Structures ◽  
Computed Tomographic ◽  
The Mean ◽  
Chamber Floor

Background: There are a few studies about the evaluation of maxillary first premolars internal structure with micro-computed tomography (micro-CT). The aim of this study was to assess morphological features of the pulp chamber in maxillary first premolar teeth using micro- CT. Methods: Extracted 15 maxillary first premolar teeth were selected from the patients who were in different age groups. The distance between the pulp orifices, the diameter of the pulp and the width of the pulp chamber floor were measured on the micro-CT images with the slice thickness of 13.6 µm. The number of root canal orifices and the presence of isthmus were evaluated. Results: The mean diameter of orifices was 0.73 mm on the buccal side while it was 0.61 mm on palatinal side. The mean distance between pulp orifices was 2.84 mm. The mean angle between pulp orifices was -21.53°. The mean height of pulp orifices on the buccal side was 4.32 mm while the mean height of pulp orifices on the palatinal side was 3.56 mm. The most observed shape of root canal orifices was flattened ribbon. No isthmus was found in specimens. Conclusion: Minor anatomical structures can be evaluated in more detail with micro-CT. The observation of the pulp cavity was analyzed using micro-CT.

scholarly journals Skull shape differentiation of black and white olms (Proteus anguinus anguinus and Proteus a. parkelj): an exploratory analysis with micro-CT scanning

2013 ◽  
Vol 82 (2) ◽  
pp. 107-114 ◽  
Author(s):  
Ana Ivanović ◽  
Gregor Aljančič ◽  
Jan W. Arntzen
Keyword(s):  
Morphological Differentiation ◽  
Ct Scanning ◽  
Exploratory Analysis ◽  
Micro Ct ◽  
Black And White ◽  
Necturus Maculosus ◽  
Proteus Anguinus ◽  
Evolutionary Trajectories ◽  
Morphological Detail ◽  
Shape Changes

We performed an exploratory analysis of the morphology of the cranium in the white olm (Proteus anguinus anguinus) and the black olm (P. a. parkelj) with micro-CT scanning and geometric morphometrics. The mudpuppy (Necturus maculosus) was used as an outgroup. The black olm falls outside the white olm morphospace by a markedly wider skull, shorter vomers which are positioned further apart and by laterally positioned squamosals and quadrates relative to the palate (the shape of the buccal cavity). On account of its robust skull with more developed premaxillae a shorter otico-occipital region, the black olm is positioned closer to Necturus than are the studied specimens of the white olm. The elongated skull of the white olm, with an anteriorly positioned jaw articulation point, could be regarded as an adaptation for improved feeding success, possibly compensating for lack of vision. As yet, the alternative explanations on the evolution of troglomorphism in Proteus are an extensive convergence in white olms versus the reverse evolution towards less troglomorphic character states in the black olm. To further understand the evolutionary trajectories within Proteus we highlight the following hypotheses for future testing: i) morphological differentiation is smaller within than between genetically differentiated white olm lineages, and ii) ontogenetic shape changes are congruent with the shape changes between lineages. We anticipate that the morphological detail and analytical power that come with the techniques we here employed will assist us in this task.

scholarly journals A Microcomputed Tomographic Evaluation of Root Canal Morphology of Maxillary Second Premolars in a Pakistani Cohort

2021 ◽  
Vol 11 (11) ◽  
pp. 5086
Author(s):  
Mazen F. Alkahtany ◽  
Saqib Ali ◽  
Abdul Khabeer ◽  
Shafqat A. Shah ◽  
Khalid H. Almadi ◽  
...  
Keyword(s):  
Root Canal ◽  
Three Dimensional ◽  
Ct Scanning ◽  
Micro Ct ◽  
Single Root ◽  
Root Canal Morphology ◽  
Spss Software ◽  
Variable Morphology ◽  
Canal Morphology

This study aimed to investigate variations in the root canal morphology of maxillary second premolar (MSP) teeth using microcomputed tomography (micro-CT). Sixty (N = 60) human extracted MSPs were collected and prepared for micro-CT scanning. The duration for scanning a single sample ranged between 30 and 40 min and a three-dimensional (3-D) image was obtained for all the MSPs. The images were evaluated by a single observer who recorded the canal morphology type, number of roots, canal orifices, apical foramina(s), apical delta(s), and accessory canals. The root canal configuration was categorized in agreement with Vertucci’s classification, and any configuration not in agreement with Vertucci’s classification was reported as an “additional canal configuration”. Descriptive statistics (such as mean percentages) were calculated using SPSS software. The most common types agreeing with Vertucci’s classification (in order of highest to lowest incidence) were types I, III, V, VII, II, and VI. The teeth also exhibited four additional configurations that were different from Vertucci’s classification: types 2-3, 1-2-3, 2-1-2-1, and 1-2-1-3. A single root was found in 96.7% and the majority of the samples demonstrated two canals (73.3%). Further, 80% of the teeth showed one canal orifice. The number of apical foramina’s in the teeth was variable, with 56.7% having solitary apical foramen. The accessory canal was found in 33.3%, and apical delta was found in only 20% of the samples. Variable morphology of the MSPs was detected in our study. The canal configuration most prevalent was type 1; however, the results also revealed some additional canal types.

scholarly journals Timing of Mouse Molar Formation Is Independent of Jaw Length Including Retromolar Space

2021 ◽  
Vol 9 (1) ◽  
pp. 8
Author(s):  
Daisy (Jihyung) Ko ◽  
Tess Kelly ◽  
Lacey Thompson ◽  
Jasmene K. Uppal ◽  
Nasim Rostampour ◽  
...  
Keyword(s):  
Onset Time ◽  
Ct Scanning ◽  
Micro Ct ◽  
Third Molars ◽  
Developmental Duration ◽  
Dental Lamina ◽  
Permanent Molars ◽  
Dental Epithelium ◽  
Space Conditions

For humans and other mammals to eat effectively, teeth must develop properly inside the jaw. Deciphering craniodental integration is central to explaining the timely formation of permanent molars, including third molars which are often impacted in humans, and to clarifying how teeth and jaws fit, function and evolve together. A factor long-posited to influence molar onset time is the jaw space available for each molar organ to form within. Here, we tested whether each successive molar initiates only after a minimum threshold of space is created via jaw growth. We used synchrotron-based micro-CT scanning to assess developing molars in situ within jaws of C57BL/6J mice aged E10 to P32, encompassing molar onset to emergence. We compared total jaw, retromolar and molar lengths, and molar onset times, between upper and lower jaws. Initiation time and developmental duration were comparable between molar upper and lower counterparts despite shorter, slower-growing retromolar space in the upper jaw, and despite size differences between upper and lower molars. Timing of molar formation appears unmoved by jaw length including space. Conditions within the dental lamina likely influence molar onset much more than surrounding jaw tissues. We theorize that molar initiation is contingent on sufficient surface area for the physical reorganization of dental epithelium and its invagination of underlying mesenchyme.

scholarly journals Rhinocerotidae from the early Miocene of the Negev (Israel) and implications for the dispersal of early Neogene rhinoceroses

2021 ◽  
pp. 1-12
Author(s):  
Luca Pandolfi ◽  
Ran Calvo ◽  
Ari Grossman ◽  
Rivka Rabinovich
Keyword(s):  
Southeast Asia ◽  
South Asian ◽  
North Africa ◽  
Range Expansion ◽  
New Records ◽  
Ct Scanning ◽  
Early Miocene ◽  
Early Neogene ◽  
Postcranial Remains

Abstract A revision of the rhinocerotid material from the Negev (Israel), dating back to the early Miocene (MN3 in the European Mammal Biochronology), highlights the presence of Brachypotherium and a taxon close to Gaindatherium in the Levantine corridor. A juvenile mandible, investigated using CT scanning, displays morphologically distinct characters consistent with Brachypotherium cf. B. snowi rather than with other Eurasian representatives of this genus. Some postcranial remains from the Negev, such as a humerus, display features that distinguish it among Miocene taxa. We attribute these postcrania to cf. Gaindatherium sp., a taxon never recorded outside the Siwaliks until now. This taxon dispersed into the Levantine region during the late early Miocene, following a pattern similar to other South Asian taxa. Brachypotherium cf. B. snowi probably occurred in the Levantine region and then in North Africa during the early Miocene because its remains are known from slightly younger localities such as Moghara (Egypt) and Jebel Zelten (Libya). The occurrence cf. Gaindatherium sp. represents a previously unrecorded range expansion out of Southeast Asia. These new records demonstrate the paleogeographic importance of the Levantine region showcasing the complex role of the Levantine corridor in intercontinental dispersals between Asia and Europe as well as Eurasia and Africa.

MicroCT protocols for scanning of embryos and juvenile Hexaplex trunculus v1

2021 ◽  
Author(s):  
Eva Chatzinikolaou ◽  
Kleoniki Keklikoglou
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
3D Imaging ◽  
Imaging Technique ◽  
Ct Scanning ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
Gastropod Species ◽  
Biological Studies ◽  
Hexaplex Trunculus

Micro-computed tomography (micro-CT) is a high-resolution 3D-imaging technique which is now increasingly applied in biological studies focusing on taxonomy and functional morphology. The creation of virtual representations of specimens can increase availability of otherwise underexploited and inaccessible samples. This protocol aims to standardise micro-CT scanning procedures for embryos and juveniles of the marine gastropod species Hexaplex trunculus.

scholarly journals A Preliminary Report on the Use of Bench-Top X-Ray Micro-Computerised Tomography to Study the Malpighian Tubules of the Overwintering Seven Spotted LadybirdCoccinella septempunctataL. (Coleoptera: Coccinellidae)

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Duncan Bell ◽  
Lewis Woolnough ◽  
David Mortimore ◽  
Nick Corps ◽  
Diana M. Hudson ◽  
...  
Keyword(s):  
Coccinella Septempunctata ◽  
Ct Scanning ◽  
Small Sample ◽  
Malpighian Tubules ◽  
Micro Ct ◽  
Computerised Tomography ◽  
X Ray ◽  
High Concentrations ◽  
Very High ◽  
Metallic Pollutants

The application of micro-CT scanning techniques on a small sample of “Seven-spot ladybirds”Coccinella septempunctata,collected in December 2009, identified an accumulation of material with a very high, relative X-ray attenuation value in the malpighian tubules of most but not all of the individuals sampled. The passage of metals such as cadmium in soil through a food chain to finally accumulate in high concentrations in ladybirds and lacewings has been previously reported. The identification of the dense material found in our sample of ladybirds, its origin, and the process by which it accumulates in, and is processed by, the malpighian tubules is the challenge ahead. The authors speculate that a straightforward means of monitoring levels of metallic pollutants in the environment might emerge.

Endothelin B Receptor Mutant Exhibits Craniofacial Dysmorphology Resembling Domestication Syndrome

2021 ◽  
Author(s):  
Ko-Chin Chen ◽  
Allison Gee ◽  
Geoffrey Croaker
Keyword(s):  
3D Visualization ◽  
Ct Scanning ◽  
Control Group ◽  
Micro Ct ◽  
Domestication Syndrome ◽  
Skull Length ◽  
Interorbital Width ◽  
Obstructive Sleep ◽  
Model Animal ◽  
Nasal Length

Abstract Background: ETB-/- mutation is a major cause of HSCR, a neurocristopathy known for its enteric nervous system failure. Other than regulating ENCC migration, ETB mediates ET-1 clearance. Consequently, ETB may indirectly affect ET-1/ETA signaling, which controls CNCC migration and craniofacial development. Interestingly, it was hypothesized that “domestication syndrome” arise from changes in neural crest determining genes, including ETA and ETB. While ETA-/- animals are known to suffer severe dysmorphology resembling CATCH22 syndrome, we hypothesize that sl/sl rat, an ETB-/- HSCR model animal, may exhibit subtle craniofacial changes through indirect control. These features may share resemblance to those of domestication syndrome. Methods: Ten rat pups with an average age of 88 hours were anaesthetized with 5% isoflurane and culled via exsanguination. Tail tips were removed for genotyping. Head tissue were stained in 1.5% iodine for two weeks prior to micro-CT scanning. In vivo micro-CT scanning of cranial specimen was performed followed by ex vivo micro-CT scanning of 2 samples for image quality control. 3D visualization and analyses were performed using open-source program, Drishti. Cephalometric measurements were made based on selected craniofacial landmarks. Comparisons were made between sl/sl rats and the control group, which consisted of wild-type and heterozygotes. Results: Subtle reductions in facial measurements were seen in sl/sl rats when compared with the control group, ranging from 1.4% to 15%. These changes were observed in cranial, maxillary and mandibular parameters: total skull length, nasal length, nasal width, nasal cavity width, interorbital width, interlens distance, inner and outer canthal distance, maximal skull height, cranial length, intracranial length and width, interorbital width, and interzygomatic width. Consistently, craniofacial ratio indices showed sl/sl rat has a flatter cranium (skull height/skull length: 0.393 vs 0.413) and a shorter but broader nose (nasal-width/nasal-length: 0.794 vs 0.874). Additionally, subtle dystopia canthorum may be presented in sl/sl rat based on increased W index. While there was no discrepancy in dental number and morphology between the control and sl/sl groups, dimensional difference was detected. Conclusions: This study demonstrated subtle craniofacial changes are presented in ETB-/- HSCR model, supporting the idea that ETB regulates CNCC migration. The findings also implicate HSCR patient may have predisposing risks for conditions such as obstructive sleep apnea, cleft palate, or dental malocclusion. Lastly, these changes share resemblance with described domestication syndrome, supporting NCC-determining gene, ETB, may play a role in the formation of domestication.

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