scholarly journals Mandible histology in Metoposaurus krasiejowensis (Temnospondyli, Stereospondyli) from the Upper Triassic of Poland

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12218
Author(s):  
Kamil Gruntmejer ◽  
Adam Bodzioch ◽  
Dorota Konietzko-Meier
Keyword(s):  
Anterior Part ◽  
Shoulder Girdle ◽  
Late Triassic ◽  
Middle Region ◽  
Thin Sections ◽  
Histological Data ◽  
Small Primary ◽  
Dermal Bones ◽  
Highly Porous ◽  
Metoposaurus Krasiejowensis

Recent studies that have systematically augmented our knowledge of dermal bones of the Late Triassic temnospondyl amphibian Metoposaurus krasiejowensis have mostly focused on shoulder girdle elements and the skull. So far, histological data on the mandible are still scant. For the present study, two mandibles have been examined, using 50 standard thin sections. Dermal bones of the mandible reveal a uniform diploë structure, with the external cortex consisting of moderately vascularised, parallel-fibred bone, as well as a distinct alternation of thick zones and thinner annuli. Dense bundles of well-mineralised Sharpey’s fibres are seen in the external cortex over the entire length of the mandible. The trabecular middle region is highly porous and well vascularised, showing small primary vascular canals and more numerous secondary osteons; irregular erosion spaces occur in large numbers as well. The thin and poorly vascular internal cortex consists of parallel-fibred bone. The articular is not a dermal bone in origin, having been formed of a thin layer of avascular cortex and a very extensive, trabecular middle region. In contrast to the dermal bones of the mandible, the articular developed from a cartilaginous precursor, as evidenced by numerous remains of calcified cartilage in the central parts of the bone. Histological variability is extremely high along the mandible, its anterior part being characterised by high compactness and biomechanically good resistance in contrast to the highly porous posterior parts. Distinct variations of bone thickness and degree of bone porosity in specific areas of the mandible, may be due to local differences in biomechanics during feeding. The microstructure of the mandible corroborates a previous study of the active and ambush predation strategy in metoposaurids.

scholarly journals Cranial bone histology ofMetoposaurus krasiejowensis(Amphibia, Temnospondyli) from the Late Triassic of Poland

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2685 ◽  
Author(s):  
Kamil Gruntmejer ◽  
Dorota Konietzko-Meier ◽  
Adam Bodzioch
Keyword(s):  
Bone Development ◽  
Cranial Bone ◽  
Late Triassic ◽  
Cranial Development ◽  
Biomechanical Loading ◽  
Calcified Cartilage ◽  
Single Bone ◽  
Occipital Condyles ◽  
Dermal Bones ◽  
Metoposaurus Krasiejowensis

In this study, 21 skull bones ofMetoposaurus krasiejowensisfrom the Late Triassic of Poland were investigated histologically. Dermal bones show a diploë structure, with an ornamented external surface. The ridges consist of mostly well vascularized parallel-fibered bone; the valleys are built of an avascular layer of lamellar bone. The thick middle region consists of cancellous bone, with varying porosity. The thin and less vascularized internal cortex consists of parallel-fibered bone. The numerous Sharpey’s fibers and ISF are present in all bones. The cyclicity of growth is manifested as an alternation of thick, avascular annuli and high vascularized zones as well as a sequence of resting lines. The detailed histological framework of dermal bones varies even within a single bone; this seems to be related to the local biomechanical loading of the particular part of the skull. The dynamic processes observed during the ornamentation creation indicate that the positions of the ridges and grooves change during growth and could be a specific adaptation to changing biomechanical conditions and stress distribution during bone development. In the supratemporal, the cementing lines show that the remodeling process could be involved in the creations of sculpture. The common occurrence of ISF suggests that metaplastic ossification plays an important role during cranial development. Endochondral bones preserved the numerous remains of calcified cartilage. This indicates that ossification follows a pattern known for stereospondyl intercentra, with relatively slow ossification of the trabecular part and late development of the periosteal cortex. The large accumulation of Sharpey’s fibers in the occipital condyles indicates the presence of strong muscles and ligaments connecting the skull to the vertebral column.

scholarly journals Ontogeny of Polycotylid Long Bone Microanatomy and Histology

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
F R O’Keefe ◽  
P M Sander ◽  
T Wintrich ◽  
S Werning
Keyword(s):  
Sudden Change ◽  
Late Triassic ◽  
Long Bone ◽  
Thin Sections ◽  
Growth Series ◽  
Marrow Cavity ◽  
Pierre Shale ◽  
Calcified Cartilage ◽  
Histological Data ◽  
History Of

Abstract Plesiosauria is an extinct clade of diapsid marine reptiles that evolved in the Late Triassic and radiated globally for the remainder of the Mesozoic. The recent description of a pregnant specimen of Polycotylus latipinnis demonstrates that some plesiosaurs were viviparous. To establish a baseline of histological data on plesiosaur ontogeny, we sampled the mother and fetus of the gravid plesiosaur specimen. To widen the base of data concerning ontogeny and life history of plesiosaurs, we gathered additional morphologic and histologic data from a securely identified growth series of polycotylids from the Pierre Shale of South Dakota. Paleohistological thin sections were prepared from the three humeri. Both adults show a dense, heavily remodeled cortex consisting entirely of longitudinally oriented secondary osteons, except for a thin rind of superficial primary bone. The mother exhibits an external fundamental system, indicating it was fully mature; the other adult does not. In both adults the cortex grades into a spongy medulla, comprising large vascular canals and erosion rooms surrounded by secondary lamellar trabecular bone, and lacking a marrow cavity. The fetal humerus possesses a medullary region similar to that of the Dolichorhynchops bonneri adult, although its lamellar bone is primary and deposited around calcified cartilage. The medulla is demarcated from the cortex by a prominent Kastschenko’s line. The cortex of the fetus is a relatively thin layer of periosteal woven bone, longitudinally to radially vascularized, and interfingered with columns of osteoblasts surrounded by rapidly-deposited extracellular matrix. The neonate humerus resembles the fetus, with its trabeculae identical in both size and histology, although it lacks calcified cartilage. The cortex is also similar but much thicker, consisting entirely of rapidly deposited, radially vascularized, woven to fibrolamellar bone. The cortex carries a line near its surface. This feature is not a line of arrested growth, but a sudden change in vascular angle and increase in bone density. We argue this feature is a birth line indicating a change in growth regime, possibly in response to increased hydrodynamic forces after birth. The birth line indicates that the neonate was about 40% of maternal length when born. Our histological data demonstrate that polycotylids had very high fetal growth rates, and that birth size was large. Comparison with the geologically oldest plesiosaur confirms that rapid growth evolved in the Triassic, although histological details differ, and the degree to which the polycotylid ontogenetic pattern is generalizable to other plesiosaurs is currently unknown. Further histological research utilizing full growth series is needed, particularly for Jurassic taxa.

scholarly journals Ornamentation of dermal bones of Metoposaurus krasiejowensis and its ecological implications

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5267 ◽  
Author(s):  
Mateusz Antczak ◽  
Adam Bodzioch
Keyword(s):  
Sexual Dimorphism ◽  
Ecological Condition ◽  
Late Triassic ◽  
Ecological Studies ◽  
Ecological Adaptations ◽  
Water Accessibility ◽  
Ecological Implications ◽  
Dermal Bones ◽  
Temperature Water ◽  
Metoposaurus Krasiejowensis

Background Amphibians are animals strongly dependent on environmental conditions, like temperature, water accessibility, and the trophic state of the reservoirs. Thus, they can be used in modern palaeoenvironmental analysis, reflecting ecological condition of the biotope. Methods To analyse the observed diversity in the temnospondyl Metoposaurus krasiejowensis from Late Triassic deposits in Krasiejów (Opole Voivodeship, Poland), the characteristics of the ornamentation (such as grooves, ridges, tubercules) of 25 clavicles and 13 skulls were observed on macro- and microscales, including the use of a scanning electron microscope for high magnification. The different ornamentation patterns found in these bones have been used for taxonomical and ecological studies of inter- vs. intraspecific variation. Results Two distinct types of ornamentation (fine, regular and sparse, or coarse, irregular and dense) were found, indicating either taxonomical, ecological, individual, or ontogenetic variation, or sexual dimorphism in M. krasiejowensis. Discussion Analogies with modern Anura and Urodela, along to previous studies on temnospondyls amphibians and the geology of the Krasiejów site suggest that the differences found are rather intraspecific and may suggest ecological adaptations. Sexual dimorphism and ontogeny cannot be undoubtedly excluded, but ecological variation between populations of different environments or facultative neoteny (paedomorphism) in part of the population (with types of ornamentations being adaptations to a more aquatic or a more terrestrial lifestyle) are the most plausible explanations.

scholarly journals Actinopterygians of The Permian Locality Buxières-Les-Mines (Bourbonl’archambault Basin, France) and Their Relationship to Other Early Actinopterygians

2018 ◽  
Vol 74 (3-4) ◽  
pp. 245-291
Author(s):  
Stanislav Štamberg
Keyword(s):  
Coal Mine ◽  
Shoulder Girdle ◽  
Great Variability ◽  
Anatomical Features ◽  
The Third ◽  
Skull Roof ◽  
New Knowledge ◽  
Main Component ◽  
The Village ◽  
Dermal Bones

Actinopterygians from the large opencast coal mine in the vicinity of the village of Buxières-les-Mines (Bourbonl’Archambault Basin, Allier, France) are revisited and redescribed based on newly studied specimens. The understanding of the anatomy of Progyrolepis heyleri POPLIN, 1999, originally described by Poplin (1999) on the basis of the upper and lower jaws only, is greatly enhanced and is relatively complete. The anatomy of the palatoquadrate, dermal bones of the skull roof, hyoid arch, operculum, suboperculum, shoulder girdle, cheek bones and branchiostegal rays is described. In addition, new observations have been made on changes in the shape of the maxilla during ontogenesis and microstructure of the teeth. Details of Progyrolepis heyleri scales, including their microstructure and morphology of the ridge scales are provided. The collection of whole individuals, body fragments and numerous isolated bones provide confirmation of the presence of Aeduella blainvillei which is the main component of the actinopterygian fauna in Buxières-les-Mines. Additional new knowledge was obtained regarding the great variability in bones of the opercular apparatus and maxilla, presence of the supraorbital, branchiostegal ray with a conspicuous hyoid process and the direction of mutual overlapping of the suboperculum and branchiostegal ray in Aeduella blainvillei (AGASSIZ, 1833). Microsculpture on the scales is redescribed in this species. Paramblypterus cf. duvernoy is the third member of the actinopterygians in the locality Buxières-les-Mines. Fragments of Paramblypterus are very rare and the bones of the skull roof are presented here. Anatomical features of Progyrolepis heyleri, Aeduella blainvillei and Paramblypterus cf. duvernoy were studied and compared with those of other Devonian and Permo-Carboniferous actinopterygians.

Global carbon isotope signal in the Middle Triassic on Svalbard

2021 ◽  
Author(s):  
Victoria S. Engelschiøn ◽  
Øyvind Hammer ◽  
Fredrik Wesenlund ◽  
Jørn H. Hurum ◽  
Atle Mørk
Keyword(s):  
Carbon Isotope ◽  
Depositional Environment ◽  
Middle Triassic ◽  
Barents Sea ◽  
Water Productivity ◽  
Sedimentary Environment ◽  
The Arctic ◽  
Late Triassic ◽  
Triassic Boundary ◽  
Thin Sections

<p>Several carbon isotope curves were recently published for the Early and Middle Triassic in Tethys. Recent work has also been done on the Early Triassic of Svalbard, but not yet for the Middle Triassic. This work is the first to measure δ<sup>13</sup>C for different Middle Triassic localities on Svalbard, which was then part of the Boreal Ocean on northern Pangea. Our aim is to understand the controls on the Svalbard carbon isotope curve and to place them in a global setting.</p><p>Correlating Triassic rocks around the world is interesting for several reasons. The Triassic Period was a tumultuous time for life, and the Arctic archipelago of Svalbard has shown to be an important locality to understand the early radiation of marine vertebrates in the Triassic. Much effort is also made to understand the development of the Barents Sea through Svalbard’s geology.</p><p>Carbon isotope curves are controlled by depositional environment and global fluctuations. Global factors such as the carbon cycle control the long-term carbon isotopic compositions, while short-term fluctuations may reflect the origin of organic materials in the sediment (e.g. algal or terrestrial matter), stratification of the water column, and/or surface water productivity. Carbon isotopes can therefore be useful to understand the depositional environment and to correlate time-equivalent rocks globally.</p><p>The dataset was collected through three seasons of fieldwork in Svalbard with localities from the islands Spitsbergen, Edgeøya and Bjørnøya. Detailed stratigraphic sampling has resulted in high-resolution δ<sup>13</sup>C curves. These show three strong transitions; 1) on the boundary between the Early and Middle Triassic, 2) in the middle of the formation and 3) at the Middle and Late Triassic boundary. Several Tethyan localities show a possibly similar Early-Middle Triassic signal. Current work in progress is sedimentological analysis by thin sections and X-ray fluorescence spectroscopy (XRF) to further understand the sedimentary environment.</p>

TERMINOLOGY OF PALEOZOIC PLACODERM FISHES (ANTIARCHI) EXOSKELETAL ELEMENTS

2021 ◽  
Vol 43 (2) ◽  
pp. 195-201
Author(s):  
Sergey Moloshnikov ◽  
Keyword(s):  
Anterior Part ◽  
Posterior Part ◽  
Shoulder Girdle ◽  
Russian Language ◽  
Postcranial Skeleton ◽  
Incorrect Conclusion ◽  
Similar Term ◽  
Early Vertebrates ◽  
Language Literature ◽  
Dorsal Scute

The terminology and morphology of plates of the posterior part of the antiarch head shield (Placodermi, Antiarchi) are discussed. The terms «zatilochnaya» and «bokovaya (kraevaya) zatilochnaya» was previously accepted in antiarch skulls and are suggested for use in Russian-language literature. These terms are more correct and clearly define a position and development of these plates in the head shield of antiarchs. The titles «zagrivkovaya (nuchalnaya)» and «bokovaya zagrivkovaya (paranuchalnaya)», recently applied to them in Russian-language literature may indicate a connection in development with an anterior part of a trunk. A similar term is used for acipenserid exoskeleton. The acipenserid «nuchalnaya kost’» is located posterior to the «verchnezatilochnaya» (after Gurtovoi), and embryonically developed in an anterior part of the trunk over basidorsals and bones of the shoulder girdle. The name «pervaya spinnaya plastinka» (first dorsal scute: after Hilton and others) is also use for this bone. The term «zagrivkovaya plastinka» is used in other vertebrate skeletons, for example, in turtles; this name denotes the unpaired element of a carapace (postcranial skeleton). Using the terms «zagrivkovaya (nuchalnaya)» and «bokovaya zagrivkovaya (paranuchalnaya)» in the morphology of antiarchs and other placoderms may lead confusion in the terminology of skeletal elements at early vertebrates, incorrect conclusion of their homology, structure and development of the head shield of these unusual fishes.

scholarly journals Filopodelike projections induced with dimethyl sulfoxide and their relevance to cellular polarity in Dictyostelium.

1983 ◽  
Vol 96 (3) ◽  
pp. 857-865 ◽  
Author(s):  
S Yumura ◽  
Y Fukui
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Dimethyl Sulfoxide ◽  
Cell Polarity ◽  
Cytoplasmic Streaming ◽  
Anterior Part ◽  
Cellular Polarity ◽  
Microtubule Organizing Center ◽  
Cell Organelles ◽  
Thin Sections

When 5% dimethyl sulfoxide (DMSO) was applied to Dictyostelium cells, the cells rounded up in shape and cytoplasmic streaming ceased. The cells resumed both cytoplasmic streaming and locomotion in 20 min. SDS PAGE of isolated plasma membrane fractions showed that actin and myosin apparently became dissociated from the plasma membrane by the action of DMSO. Scanning electron microscopy revealed that many filopodelike projections formed on the surface of cells treated with 5% DMSO for 5 min. Interestingly, the projections were formed on a restricted portion of the cell surface. The phagokinetic track technique of Albrecht-Buehler (1977, Cell, 11: 395-404) showed that the projection region corresponded to the anterior part of a migrating cell. The possible relationship between the DMSO-induced projection region on the cell surface and intracellular organization of cell organelles was investigated using serial thin sections. The DMSO-induced projections contained arrays of microfilaments; and the microtubule organizing center (MTOC), nucleus, and vesicular structure were usually located in this order from the anterior end of the cell. The indirect immunofluorescent study using monoclonal anti-alpha-tubulin antibody was performed with a new fixation technique, which greatly improved the phase as well as immunofluorescent microscopy. It was verified that the intracellular positioning of the MTOC and nucleus had significant correlation with the cell polarity. The results show that DMSO is a powerful tool with which to manipulate the cellular microfilaments and to make visible the differentiation in the cortex layer, which apparently is relevant to the intracellular positioning of cell organelles and cell polarity.

scholarly journals XIII. Researches on the structure, organization, and classification of the fossil reptilia. -Part IX., Section 3. On diademodon

1894 ◽  
Vol 185 ◽  
pp. 1029-1041 ◽  
Keyword(s):  
South African ◽  
Cape Town ◽  
Shoulder Girdle ◽  
Middle Region ◽  
The South ◽  
The West ◽  
Limb Bones ◽  
Lower Jaw

The South African fossils with broad, flat, tuberculate tooth-crowns of mammalian type all from the eastern part of Cape Colony. Some of the most interesting are known from fragments, which indicate nothing but the middle region of the sail. They are apparently extremely rare. Two species, with teeth well preserved, found ten years ago by Dr. Kannemeyer, at Wonderboom, and presented to South African Museum, Cape Town, where they were brought under my notice by Peringuey. Others were found in a fragmentary condition by Mr. Alfred of Aliwal North, to the west of that town, in a bed which appeared to me be reconstructed. There is no doubt that the fossils are from the upper part of te Karroo formation, probably of Permian age, and below the Stormberg beds, in Saurischian fossils are found allied to those of the Trias of Europe. If the teeth had occurred isolated, without the means of demonstrating their rsemblance to Theriodonts, by comparison of what remains of the skull, it would have legitimate to have referred them to Mammals. There is no evidence of affinity Accept resemblances to Theriodonts, which show that the skull had pre-frontal and frontal bones, and therefore may be inferred to have had the lower jaw composite. The teeth are such as might be expected, perhaps, in a Monotreme Mammal, their interest is therefore the greater that there is no ground for suspecting them be mammalian, other than a general resemblance of the crown to the crowns of true teeth of Ornithorhynchus. That teeth of this type should occur in a group animals in which the shoulder-girdle and pelvis have monotreme characters, and in hich the principal limb bones are intermediate in character between Monotremes Marsupials, is evidence of a closer approximation between Mammals and Pep tiles has been manifest. And so far as I am aware the only Theriodont characters remaining to distinguish these animals from Mammals are the composite lower which is covered externally by the dentary bone along its whole length, and the resence of the pre-frontal, post-frontal, and transverse bones in the skull.

scholarly journals Climatic influence on the growth pattern of Panthasaurus maleriensis from the Late Triassic of India deduced from paleohistology

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9868
Author(s):  
Elżbieta M. Teschner ◽  
Sanjukta Chakravorti ◽  
Dhurjati P. Sengupta ◽  
Dorota Konietzko-Meier
Keyword(s):  
Growth Pattern ◽  
Environmental Influence ◽  
Wide Spectrum ◽  
Climatic Conditions ◽  
Bone Histology ◽  
Late Triassic ◽  
Tissue Type ◽  
Thin Sections ◽  
Local Climate ◽  
Limb Bones

Metoposaurids are representatives of the extinct amphibian clade Temnospondyli, found on almost every continent exclusively in the Late Triassic deposits. Osteohistologically, it is one of the best-known temnospondyl groups, analyzed with a wide spectrum of methods, such as morphology, morphometry, bone histology or computed modelling. The least known member of Metoposauridae is Panthasaurus maleriensis from the Pranhita-Godavari basin in Central India, being geographically the most southern record of this family. For the first time the bone histology of this taxon was studied with a focus on the intraspecific variability of the histological framework and the relationship between the observed growth pattern and climatic and/or environmental conditions. The studied material includes thin-sections of five long bones, a rib, an ilium and an intercentrum belonging most likely to eight individuals ranging from different ontogenetic stages. All bones have a large medullary region with progressively increasing remodeling, surrounded by a lamellar-zonal tissue type. The primary cortex consists of parallel-fibered matrix showing various degrees of organization, less organized collagen fibers in the zones and higher organized in the annuli. Growth marks occur in the form of alternating zones and annuli in every bone except the ilium and the intercentrum. The vascularity becomes less dense towards the outermost cortex in all sampled limb bones. Towards the outermost cortex the zone thickness is decreasing, in contrast to the avascular annuli, that become thicker or are of the same thickness. The growth pattern of P. maleriensis is uniform and represents changes in ontogenetic development. Multiple resting lines are prominent in the outer annuli of the limb bones and the rib and they presumably indicate climatic and environmental influence on the growth pattern. Therefore, a prolonged phase of slowed-down growth occurred during the unfavorable phase, but a complete cessation of growth indicated by Lines of Arrested Growth (LAGs) is not recorded in the studied samples. Based on the histological framework we conclude that the climate had an impact on the growth pattern. As we do not see any LAGs in the Indian metoposaurid, we assume that the local climate was relatively mild in India during the Late Triassic. A similar prolonged phase of slowed down growth without the occurrence of LAGs was observed in Metoposaurus krasiejowensis from the Late Triassic of Krasiejów (Poland). This is in contrast to Moroccan metoposaurid Dutuitosaurus ouazzoui from the Late Triassic of Argana Basin, where LAGs are regularly deposited throughout ontogeny indicating most likely harsher climatic conditions.

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