scholarly journals A functional evaluation of feeding in the surgeonfish Ctenochaetus striatus : the role of soft tissues

2018 ◽  
Vol 5 (1) ◽  
pp. 171111 ◽  
Author(s):  
Sterling B. Tebbett ◽  
Christopher H. R. Goatley ◽  
Víctor Huertas ◽  
Michalis Mihalitsis ◽  
David R. Bellwood
Keyword(s):  
Feeding Ecology ◽  
High Speed ◽  
Soft Tissues ◽  
Particulate Material ◽  
Functional Evaluation ◽  
Micro Computed Tomography ◽  
Lower Jaw ◽  
Computed Tomography Scanning ◽  
Tomography Scanning

Ctenochaetus striatus is one of the most abundant surgeonfishes on Indo-Pacific coral reefs, yet the functional role and feeding ecology of this species remain unclear. This species is reported to possess a rigid structure in its palate that is used for scraping, but some authors have reported that this element is comprised of soft tissue. To resolve the nature and role of this structure in the feeding ecology of C. striatus we examined evidence from anatomical observations, scanning electron microscopy, histology, X-ray micro-computed tomography scanning, high-speed video and field observations. We found that C. striatus from the Great Barrier Reef possess a retention plate (RP) on their palates immediately posterior to the premaxillary teeth which is soft, covered in a thin veneer of keratin with a papillate surface. This RP appears to be used during feeding, but does not appear to be responsible for the removal of material, which is achieved primarily by a fast closure of the lower jaw. We infer that the RP acts primarily as a ‘dustpan’, in a ‘dustpan and brush’ feeding mechanism, to facilitate the collection of particulate material from algal turfs.

Ontogenetic development of the otic region in the new model organism, Leucoraja erinacea (Chondrichthyes; Rajidae)

2018 ◽  
Vol 109 (1-2) ◽  
pp. 105-114 ◽  
Author(s):  
Cathrin PFAFF ◽  
Jürgen KRIWET ◽  
Kyle MARTIN ◽  
Zerina JOHANSON
Keyword(s):  
Soft Tissues ◽  
Developmental Stages ◽  
Model Organism ◽  
Model Organisms ◽  
Biological Research ◽  
Developmental Studies ◽  
Micro Computed Tomography ◽  
Computed Tomography Scanning ◽  
Cartilaginous Fishes ◽  
Tomography Scanning

ABSTRACTCartilaginous fishes have a long evolutionary history dating back 440 million years and include model organisms in a number of fields of biological research. However, comparative developmental studies of these organisms, particularly neuroanatomical investigations, still remain sparse. Here, pre-hatching to adult developmental stages of the Little Skate, Leucoraja erinacea, are investigated using micro-computed tomography scanning in conjunction with staining procedures designed to improve visualisation of soft tissues. Within the ear, the anatomy of the skeletal labyrinth changes during ontogeny and differs substantially from the underlying membranous system, contrary to previous observations in sharks. Additionally, substantial morphological remodelling characterises the parietal fossa, which appears initially as a massive and hook-like structure and subsequently becomes slender and surrounded by soft tissue. The sizes of the vestibular system and neurocranium increase isometrically from pre- to post-hatching phases, and then exponentially after the post-hatching stages.

scholarly journals Morphology and performance of the ‘trap-jaw’ cheliceral strikes in spiders (Araneae, Mecysmaucheniidae)

2020 ◽  
Vol 223 (14) ◽  
pp. jeb219899 ◽  
Author(s):  
Hannah M. Wood
Keyword(s):  
High Speed ◽  
Micro Computed Tomography ◽  
Kinematic Data ◽  
Computed Tomography Scanning ◽  
Structural Differences ◽  
Angular Velocities ◽  
Spring System ◽  
3D Printed ◽  
And Performance ◽  
Tomography Scanning

ABSTRACTMecysmaucheniidae spiders have evolved ultra-fast cheliceral strikes 4 times independently. The mechanism for producing these high-speed strikes is likely due to a latch/spring system that allows for stored energy to be rapidly released. This study examined two different sister lineages: Zearchaea has ultra-fast cheliceral strikes and Aotearoa, based on external morphology of the clypeus, is hypothesized to have slower strikes. Using high-speed videography, I first gathered kinematic data on each taxon. Then, using histology and data from micro-computed tomography scanning, I examined internal cheliceral muscle morphology to test whether shifts in muscle anatomy correspond to performance differences in cheliceral strike. Results from high-speed video analysis revealed that Zearchaea achieves peak angular velocities of 25.0×103±4.8×103 rad s−1 (mean±s.d.) in durations of 0.0843±0.017 ms. The fastest recorded strike had a peak angular and linear velocity of 30.8×103 rad s−1 and 18.2 m s−1, respectively. The slower striking sister species, Aotearoa magna, was three orders of magnitude slower in velocity and longer in duration. Histology revealed sarcomere length differences, with some muscles optimized for force, and other muscles for speed. 3D printed models revealed structural differences that explain how the chelicerae hinge open and close. Combining all of this evidence, I put forth a hypothesis for the ultra-fast trap-jaw mechanism. This research documents the morphological shifts that accompany ultra-fast movements that result in increased rotation in joints and increased muscle specialization.

scholarly journals Exposure to the RXR agonist SR11237 in early life causes disturbed skeletal morphogenesis in a rat model

2019 ◽  
Author(s):  
Holly Dupuis ◽  
Michael Andrew Pest ◽  
Ermina Hadzic ◽  
Thin Xuan Vo ◽  
Daniel B. Hardy ◽  
...  
Keyword(s):  
Growth Plate ◽  
Bone Growth ◽  
Long Bone ◽  
Tunel Staining ◽  
Long Bones ◽  
Micro Computed Tomography ◽  
Computed Tomography Scanning ◽  
Calcified Tissue ◽  
Trap Staining ◽  
Tomography Scanning

AbstractLongitudinal bone growth occurs through endochondral ossification (EO), controlled by various signaling molecules. Retinoid X Receptor (RXR) is a nuclear receptor with important roles in cell death, development, and metabolism. However, little is known about its role in EO. In this study, the agonist SR11237 was used to evaluate RXR activation on EO.Rats given SR11237 from post-natal day 5 to 15 were harvested for micro-computed tomography scanning and histology. In parallel, newborn CD1 mouse tibiae were cultured with increasing concentrations of SR11237 for histological and whole mount evaluation.RXR agonist-treated rats were smaller than controls, and developed dysmorphia of the growth plate. Cells invading the calcified and dysmorphic growth plate appeared pre-hypertrophic in size and shape corresponding with P57 immunostaining. Additionally, SOX9 positive cells were found surrounding the calcified tissue. The epiphysis of SR11237 treated bones showed increased TRAP staining, and additional TUNEL staining at the osteo-chondral junction. MicroCT revealed morphological disorganization in the long bones of treated animals. Isolated mouse long bones treated with SR11237 grew significantly less than their DMSO controls.This study demonstrates that stimulation of the RXR receptor causes irregular ossification, premature closure of the growth plate, and disrupted long bone growth in rodent models.

scholarly journals Beam hardening artifacts in micro-computed tomography scanning can be reduced by X-ray beam filtration and the resulting images can be used to accurately measure BMD

Bone ◽  
2009 ◽  
Vol 45 (6) ◽  
pp. 1104-1116 ◽  
Author(s):  
Jeffrey A. Meganck ◽  
Kenneth M. Kozloff ◽  
Michael M. Thornton ◽  
Stephen M. Broski ◽  
Steven A. Goldstein
Keyword(s):  
Computed Tomography ◽  
Micro Computed Tomography ◽  
Beam Hardening ◽  
X Ray ◽  
Computed Tomography Scanning ◽  
Tomography Scanning

scholarly journals New information on the braincase and inner ear of Euparkeria capensis Broom: implications for diapsid and archosaur evolution

2016 ◽  
Vol 3 (7) ◽  
pp. 160072 ◽  
Author(s):  
Gabriela Sobral ◽  
Roland B. Sookias ◽  
Bhart-Anjan S. Bhullar ◽  
Roger Smith ◽  
Richard J. Butler ◽  
...  
Keyword(s):  
Lateral View ◽  
Micro Computed Tomography ◽  
Active Lifestyle ◽  
Pressure Relief ◽  
New Information ◽  
Computed Tomography Scanning ◽  
Anterior Semicircular Canal ◽  
First Time ◽  
Tomography Scanning ◽  
Hearing System

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.

scholarly journals ENAMEL THICKNESS MEASUREMENTS ON 3D RECONSTRUCTIONS OF TEETH FOR PALEONTOLOGICAL APPLICATIONS

2021 ◽  
Vol XLIV-2/W1-2021 ◽  
pp. 61-65
Author(s):  
A. V. Gaboutchian ◽  
V. A. Knyaz ◽  
E. N. Maschenko ◽  
D. V. Korost ◽  
A. A. Kudaev
Keyword(s):  
Morphological Analysis ◽  
Upper Palaeolithic ◽  
Micro Computed Tomography ◽  
Enamel Thickness ◽  
Dietary Preferences ◽  
Computed Tomography Scanning ◽  
Measurement Methodology ◽  
Middle And Late Pleistocene ◽  
Thickness Measurements ◽  
Tomography Scanning

Abstract. Findings of teeth play a significant role in palaeoanthropology. And excavations in Vietnamese LangTrank cave serve as a vivid example and evidence of this statement. Teeth constitute the majority of the paleontological material dated to Middle and Late Pleistocene periods. This is to some extent the result of dietary preferences of porcupines as these rodents include in their diets bones of animals however avoiding extremely hard coronal parts of teeth. Under such circumstances teeth serve a key to taxonomic differentiation of findings as genetic analysis is often hindered by a lack of preserved DNA at such dating of material. However morphological analysis is difficult in some cases either, as teeth can be worn out or broken. In that case enamel thickness measurements become an effective study instrument as this feature varies between species. In the current study two teeth with clear signs of expressed dental wear, presumably upper fourth premolars of wild boar required more detailed analysis. Thus they were reconstructed after micro-computed tomography scanning similarly to other upper teeth picked for comparison: orang-utan tooth from the same location and two teeth from the Upper Palaeolithic Sunghir (they have been scanned earlier). This study required new approaches to image processing and measurement methodology due to marked attrition of the samples. The workflow and results of enamel thickness assessments which facilitated taxonomical differentiation of the findings are presented in the article.

scholarly journals The first mainland European Mesozoic click-beetle (Coleoptera: Elateridae) revealed by X-ray micro-computed tomography scanning of an Upper Cretaceous amber from Hungary

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Márton Szabó ◽  
Robin Kundrata ◽  
Johana Hoffmannova ◽  
Tamás Németh ◽  
Emese Bodor ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Upper Cretaceous ◽  
Micro Computed Tomography ◽  
Click Beetles ◽  
X Ray ◽  
The Past ◽  
Click Beetle ◽  
Computed Tomography Scanning ◽  
Source Of Information ◽  
Tomography Scanning

AbstractFossil bioinclusions in amber are invaluable source of information on the past evolution and diversity of various organisms, as well as on the paleoecosystems in general. The click-beetles, Elateridae, which originated and greatly diversified during the Mesozoic, are mostly known from the adpression-like fossils, and their diversity in the Cretaceous ambers is only poorly documented. In this study, we describe a new click-beetle based on an incomplete inclusion in ajkaite, an Upper Cretaceous (Santonian) amber from the Ajka Coal Formation from Hungary. We used X-ray micro-computed tomography scanning to reconstruct its morphology because it is deposited in an opaque piece of amber. Our results suggest that the newly described Ajkaelater merkli gen. et sp. nov. belongs to subfamily Elaterinae. It represents the first Mesozoic beetle reported from Hungary, and the first Mesozoic Elateridae formally described from mainland Europe. Our discovery supports an Eurasian distribution and diversification of Elaterinae already in the Cretaceous. The paleoenvironment of the Ajka Coal Formation agrees well with the presumed habitat preference of the new fossil taxon. The discovery of a presumably saproxylic click-beetle shed further light on the yet poorly known paleoecosystem of the Santonian present-day western Hungary.

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