shark teeth
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2022 ◽  
Author(s):  
Jonathan Y. S. Leung ◽  
Ivan Nagelkerken ◽  
Jennifer C. A. Pistevos ◽  
Zonghan Xie ◽  
Sam Zhang ◽  
...  

Author(s):  
Akshaya Rathore

Abstract: Dinosaur Fossils National Park Bagh has huge fossils reserves of late cretaceous period that includes Dinosaurs bones, whole dinosaurs’ nests, dinosaurs’ eggs, tree fossils, shark teeth, ammonites, bivalves, inoceramids, and other marine organisms. With the help of local researchers and forest staff over the period oftime we had collected fossils of many species. Firstly, we inventoried the fossils physically and documented each by maintaining Stock Registers. Digitizing the Stock Registers – to convert each register in excel file which includes all the details regarding that fossil. To make it more attractive and useful in future, we have created 3dmodels of at least one specimen of each fossils’ species. To have worldwide reach, we have created and hosted the website www.dinosaurfossilsnationalparkbagh.in . I


2021 ◽  
Author(s):  
Fadhil N. Sadooni ◽  
Hamad Al-Saad Al-Kuwari ◽  
Ahmad Sakhaee-Pour ◽  
Wael S. Matter ◽  
Indra Gunawan

Gas shale is the future hydrocarbon reservoir of Qatar. The Qatari geologic section has had important successions of gas shale at different geologic times including the Eocene Midra shale, the Cretaceous Ratawi and Nahr Umr, and the Paleozoic Qusaibah and Unayzah formations. Shale samples were collected from the outcrops of the Midra Shale in Dukhan and Umm Bab areas. Samples were subjected to geochemical analyses using XRD and RXF. Selected samples were examined under SEM and TEM microscopes. All the studied samples contain palygorskite as the main mineral and, in some cases, the only mineral present, as indicated by X-ray diffraction patterns. XRF analysis shows palygorskite range from ideal palygorskite (equal aluminum and magnesium content) to aluminous palygorskite where no magnesium is recorded. The most common other minor minerals are halite, quartz, calcite, and other clay minerals: illite, smectite and sepiolite. The palygorskite chain phyllo silicates results in a fibrous habit with channels running parallel to the fiber length. Images from Transmission Electron Microscopy (TEM) clearly show the presence of bundled lath-like crystals of palygorskite 5 to 20 nm in width and several micrometers in length. The Midra Shale was deposited in a shallow marine shelf that was subjected to clastic influx from the nearby land. Although, the Midra contains many elements that support deposition under marine conditions such as large foraminifera and shark teeth, the presence of fully developed shale horizons indicate a mixed marine-continental depositional setting. Most of the micropores are channels associated with the palygorskite laths as can be seen from the TEM images or some dissolution pores that resulted from halite and gypsum dissolution by meteoric water.


2021 ◽  
pp. 317-324
Author(s):  
Katerina KOPAKA
Keyword(s):  

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254395
Author(s):  
Giulia Bosio ◽  
Alberto Collareta ◽  
Claudio Di Celma ◽  
Olivier Lambert ◽  
Felix G. Marx ◽  
...  

The Miocene Pisco Formation, broadly exposed in the Ica Desert of southern Peru, is among the most outstanding Cenozoic marine Fossil-Lagerstätten worldwide. It is renowned for its exceptional preservation and abundance of vertebrate fossils, including a rich assemblage of whales and dolphins (Cetacea). Here, we integrate taphonomic data on 890 marine vertebrate fossils, gathered through 16 different localities. Our observations range from the taxonomic distribution, articulation, completeness, disposition and orientation of skeletons, to the presence of bite marks, associations with shark teeth and macro-invertebrates, bone and soft tissue preservation, and the formation of attendant carbonate concretions and sedimentary structures. We propose that the exceptional preservation characterising many Pisco vertebrates, as well as their exceptionally high abundance, cannot be ascribed to a single cause like high sedimentation rates (as proposed in the past), but rather to the interplay of several favourable factors including: (i) low levels of dissolved oxygen at the seafloor (with the intervention of seasonal anoxic events); (ii) the early onset of mineralisation processes like apatite dissolution/recrystallisation and carbonate mineral precipitation; (iii) rapid burial of carcasses in a soupy substrate and/or a novel mechanism involving scour-induced self-burial; and (iv) original biological richness. Collectively, our observations provide a comprehensive overview of the taphonomic processes that shaped one of South America’s most important fossil deposits, and suggest a model for the formation of other marine vertebrate Fossil-Lagerstätten.


2021 ◽  
Vol 14 (3) ◽  
pp. 135-137
Author(s):  
Fionnuala Loy ◽  
Victoria Elton

A 44-year-old male was referred to the Department of Orthodontics at Manchester Dental Hospital. He presented with pain from his heavily restored, lower right second premolar, which had an apical supplemental tooth, visible radiographically. The dentist queried whether the second premolar tooth could be extracted and the supplemental tooth aligned in its place. Clinical examination revealed no relevant abnormalities. The family and medical history were non-contributory. Panoramic tomography revealed multiple supplemental supernumerary teeth in the canine and premolar regions. Cone beam computed tomography and multidisciplinary team input were required to plan the treatment for this unusual case. CPD/Clinical Relevance: These findings highlight the management and treatment options for a case of non-syndromic, multiple supernumerary teeth. Consideration must be given to the risk of damage to adjacent structures if surgically removing supernumerary teeth, and the risk that supernumerary teeth may be ankylosed and not amenable to alignment within the arch.


BDJ ◽  
2021 ◽  
Vol 231 (1) ◽  
pp. 3-3
Author(s):  
A. Venugopal ◽  
A. Marya ◽  
M. I. Karobari
Keyword(s):  

Substantia ◽  
2021 ◽  
pp. 59-75
Author(s):  
Stefano Dominici

We present specific sources, including specimens of the Medicean cabinet and geological outcrops in Tuscany, probably used by Nicolaus Steno to build a theory on the origin of organic fossils, crystals and sedimentary strata, in order to construct the history of the Earth based on universal geometric principles. Phenomena he observed in Tuscany and in precedeing travels were revealing a sequence of events consistent with the biblical account. We propose that he devised his method to reconstruct a chronology of primordial events to demonstrate the historicity of the biblical creation in contrast to unorthodox thinking. This had been spreading in philosophical circles of northern Europe since the 1650s, circles frequented by Steno before his arrival in Tuscany in 1666. Steno knew in advance what places to visit to find fossils from literature such as Michele Mercati’s Metallotheca. This was a manuscript owned by the Florentine Carlo Dati, whom Steno probably heard about while in Paris in 1664-1665. In Tuscany he soon formed a tight interaction on matters regarding the interpretation of fossils with the local community of learned men. These included Giovanni Alfonso Borelli who was asked by Prince Leopoldo de’ Medici to provide Steno with fossils from Sicily and Malta. Steno’s theory and scale-independent, geometrical method of inquiry of geological objects found in Tuscany is hinted at in his Canis Carchariae Dissectum Caput, a geological essay completed in a few months in 1666. The theory was published in its most complete form in the so-called Prodromus of 1669. In both works he demonstrated that fossils in younger strata in the Tuscan hills, such as shark teeth and molluscan shells, have an origin analogous to solids which living animals form. In both essays he explicitly related the deposition of strata with marine fossils to the biblical flood, an idea foreshadowed in his oldest known manuscript of 1659, when he was a student in Copenhagen. He found no fossils in older sandstones of the Apennines and understood those strata to have formed before the creation of life. These discoveries  and other observations he made in Tuscany were, for Steno, the final proof that natural philosophy and biblical revelation disclose in synergy the mysteries of God’s creation.


Geology ◽  
2021 ◽  
Author(s):  
Heriberto Rochín-Bañaga ◽  
Donald W. Davis ◽  
Tobias Schwennicke

Previous U-Pb dating of fossils has had only limited success because of low uranium content and abundance of common Pb as well as element mobility during late diagenesis. We report the first accurate U-Pb dating of fossilized soft tissue from a Pliocene phosphatized bivalve mold using laser ablation–inductively coupled mass spectrometry (LA-ICPMS). The fossilized soft tissue yields a diagenetic U-Pb age of 3.16 ± 0.08 Ma, which is consistent with its late Pliocene stratigraphy and similar to the oldest U-Pb age measured on accompanying shark teeth. Phosphate extraclasts give a distinctly older age of 5.1 ± 1.7 Ma, indicating that they are likely detrital and may have furnished P, promoting phosphatization of the mold. The U-Pb ages reported here along with stratigraphic constraints suggest that diagenesis occurred shortly after the death of the bivalve and that the U-Pb system in the bivalve mold remained closed until the present. Shark teeth collected from the same horizon show variable resetting due to late diagenesis. Data were acquired as line scans in order to exploit the maximum Pb/U variation and were regressed as counts, rather than ratios, in three-dimensional space using a Bayesian statistical method.


Paleobiology ◽  
2021 ◽  
pp. 1-17
Author(s):  
Julia Türtscher ◽  
Faviel A. López-Romero ◽  
Patrick L. Jambura ◽  
René Kindlimann ◽  
David J. Ward ◽  
...  

Abstract Sharks have a long and rich fossil record that consists predominantly of isolated teeth due to the poorly mineralized cartilaginous skeleton. Tiger sharks (Galeocerdo), which represent apex predators in modern oceans, have a known fossil record extending back into the early Eocene (ca. 56 Ma) and comprise 22 recognized extinct and one extant species to date. However, many of the fossil species remain dubious, resulting in a still unresolved evolutionary history of the tiger shark genus. Here, we present a revision of the fossil record of Galeocerdo by examining the morphological diversity and disparity of teeth in deep time. We use landmark-based geometric morphometrics to quantify tooth shapes and qualitative morphological characters for species discrimination. Employing this combined approach on fossil and extant tiger shark teeth, our results only support six species to represent valid taxa. Furthermore, the disparity analysis revealed that diversity and disparity are not implicitly correlated and that Galeocerdo retained a relatively high dental disparity since the Miocene despite its decrease from four to one species. With this study, we demonstrate that the combined approach of quantitative geometric morphometric techniques and qualitative morphological comparisons on isolated shark teeth provides a useful tool to distinguish between species with highly similar tooth morphologies.


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