Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "Early Devonian" wg kryterium: Temat


Wyświetlanie 1-13 z 13
Tytuł:
Geological setting of the Milejowice-Janowice diabase intrusion: insights into post-Caledonian magmatism in the Holy Cross Mts., Poland
Autorzy:
Kowalczewski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2058772.pdf
Data publikacji:
2004
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Holy Cross Mountains
Łysogóry unit
Early Devonian
magnetic anomaly
diabase intrusion
Opis:
Near Milejowice and Janowice in the eastern part of the Łysogóry Unit of the Holy Cross Mts., Poland, a SW-NE trending diabase has been identified intruding Lower Palaeozoic strata. This intrusion causes amagnetic anomaly, with delta T values of 48-112 gamma. It is orientated perpendicular to the regional strike. Boreholes encountered one to three component dykes 2.0 to more than 10.0 m thick inclined at 75-90 degrees Celsius, generally towards the east. They are hydrothermally altered and affected by surface weathering. The intrusion is located along two independent transverse faults, "skipping" from one to another irrespective of their strike. The intrusive zone is strongly tectonically disturbed, S-curved and disrupted by faults into segments and sub-segments. Most of the diabases are slicken-sided, and locally cataclased and mylonitized. The Milejowice-Janowice diabases probably formed in the Early Devonian, i.e. late Lochkovian-early Pragian, as post-tectonic igneous rocks belonging to within-plate, continental basalts according to Krzemiński (2004). Their origin may be referred tomagmatism triggered by the extension of the Baltica passivemargin during the final Late Silurian-Early Devonian phase of its collision with eastern Avalonia. A complex and at least two-phase development ofmagmatism in the Holy Cross Mts. is envisaged.
Źródło:
Geological Quarterly; 2004, 48, 2; 135--146
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Colour patterns in Early Devonian cephalopods from the Barrandian Area: Taphonomy and taxonomy
Autorzy:
Turek, V
Powiązania:
https://bibliotekanauki.pl/articles/21864.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
colour pattern
Early Devonian
Devonian
cephalopod
Barrandian area
taphonomy
taxonomy
Bohemia
paleontology
Cephalopoda
Nautiloidea
fossil
Opis:
Five cephalopod specimens from the Lower Devonian of Bohemia (Czech Republic) preserve colour patterns. They include two taxonomically undeterminable orthoceratoids and three oncocerid nautiloids assigned to the genus Ptenoceras. The two fragments of orthocone cephalopods from the lowest Devonian strata (Lochkovian, Monograptus uniformis Zone) display colour patterns unusual in orthoceratoids. They have irregular undulating and zigzag strips that are preserved on counterparts of adapertural regions of specimens flattened in shale, despite their original aragonitic shell having been completely dissolved. These are probably the result of the proteinous pigment inside the shell wall, being substituted during diagenesis by secondary minerals leaving only an altered trace of the original shell. Orthoceratoids from sediments unsuitable for preservation of this feature discussed here thus demonstrate an exceptional case of preservation of colour patterns, not only within Devonian cephalopods but also within other Devonian molluscs. Three specimens of Ptenoceras that preserve colour patterns come from younger Lower Devonian strata. Oblique spiral adaperturally bifurcating bands are preserved in P. alatum from the Pragian and zigzags in P. nudum from the Dalejan. Juvenile specimen of Ptenoceras? sp. from the Pragian exhibits highly undulating transversal bands—a pattern resembling colour markings in some Silurian oncocerids. Dark grey wavy lines observed on the superficially abraded adapical part of a phragmocone of nautiloid Pseudorutoceras bolli and interpreted formerly to be colour markings are here reinterpreted as secondary pigmented growth lines. Other Devonian fossils including a single brachiopod and several gastropods from the Barrandian Area with preserved colour patterns are mentioned. Variety of cephalopod colour patterns, their taxonomic significance, function and significance for palaeoecological interpretation, palaeoenvironmental conditions favouring colour pattern preservation and systematic affiliation of taxa with colour pattern preserved are discussed.
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 3; 491-502
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sublethal injuries in Early Devonian cephalopod shells from Morocco
Autorzy:
Klug, C.
Powiązania:
https://bibliotekanauki.pl/articles/22322.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Ammonoidea
Bactritoidea
Devonian
Early Devonian
Gnathostomata
Morocco
cephalopod
paleontology
shell
predation
life mode
ectocochleate cephalopod
Opis:
Internal moulds of the relatively small− to moderate−size shells of Early Devonian ectocochleate cephalopods (typically <150 mm diameter) occasionally display traces of repaired shell damage. Presumably, these animals with their highly specialized buoyancy device, the phragmocone, lived in the water column. It is uncertain as to how the shells of these animals were damaged; one likely cause would be predatory attacks but the identity of the perpetrator remains uncertain. So far, no remains of arthropods capable of breaking or cutting shells have been found in the fossiliferous outcrops of this age in the Anti−Atlas (Morocco). The only macrovertebrate remains of this age are of acanthodian and placoderm fish which probably lived a more or less benthonic life style. Additionally, a fish attack on these cephalopods would probably have destroyed most of the thin−shelled conch and killed the animal. Most of the repaired shell breaks are triangular in shape which is characteristic for cephalopod bite marks. Additionally, the paired arrangement of the fractures in over 70 bactritoids supports the hypothesis that it was a cephalopod attacking another cephalopod. It cannot be excluded with certainty that occasional vertebrate attacks left traces on their shells. Fossil evidence indicates that the development of tightly coiled conchs was a rapid evolutionary event in the Ammonoidea in the Early Devonian; however, the evolution of coiling is probably not directly related to predation pressures because the ratio of injured to healthy specimens is roughly the same in Zlíchovian bactritoids with orthoconic and ammonoids with coiled shells.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exceptional soft-tissue preservation in boring ctenostome bryozoans and associated “fungal” borings from the Early Devonian of Podolia, Ukraine
Autorzy:
Olempska, E.
Powiązania:
https://bibliotekanauki.pl/articles/21117.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
soft tissue preservation
ctenostome bryozoan
bryozoan
Early Devonian
Devonian
paleontology
Podolia
Ukraine
Bryozoa
fungi
demineralization
phosphatization
Opis:
Colonies of boring ctenostome bryozoans and microborings of “fungi” that occur in the Early Devonian (Lochkovian, ~416 Ma) of Podolia, western Ukraine, have soft−tissue preserved by phosphatization. These comprise exceptional three−dimensional body walls of feeding zooids with probable parietal muscles inserted on the cystid wall, and setigerous collars twisted within the vestibulum. The presence of collars in this Early Devonian ctenostomes proves the existence of this feature for more than 416 Ma of ctenostome evolution. Phosphatized remains of the zooid walls are interpreted as relicts of the originally chitinous cystid walls. This is the first record of soft−tissue fossilization in a boring bryozoan. The presence of cavities (specialized heterozooids), empty or filled with laminated calcium phosphate, is also documented in bryozoans for the first time. These cavities are interpreted as “store−rooms” in which the bryozoans accumulated nutrients. The new taxon, Podoliapora doroshevi gen. et sp. nov. is described. In additional, phosphatised fungi−like endoliths co−occur with bryozoans.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Soft-tissue attachments in orthocerid and bactritid cephalopods from the Early and Middle Devonian of Germany and Morocco
Autorzy:
Kroger, B
Klug, C.
Mapes, R.
Powiązania:
https://bibliotekanauki.pl/articles/20326.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Cephalopoda
Germany
Orthocerida
Emsian
Morocco
Middle Devonian
soft tissue attachment
Early Devonian
Bactritida
muscle scar
Eifelian
Devonian
cephalopod
paleontology
Opis:
In the Early to Middle Devonian shale sequences of Germany and Morocco, pyritised and secondarily limonitised cephalopod remains are common. Details of the soft−tissue attachment structures are sometimes preserved on the internal moulds of the body chamber and phragmocone of these cephalopods. Some of the studied Orthocerida show a very faint annular elevation and a dorsal furrow. A few Bactritida show a distinctive annular elevation with two circular bands. The bands form a paired or threefold lobe at the dorsum of the shell. Morphological differences between Orthocerida and Bactritida suggest different soft part morphologies. A comparison of the attachment scars shows that the Bactritida are intermediate between the Orthocerida and ammonoids with regard to their muscle attachment scars. The shape of the muscle scars are interpreted as indication for a planktonic lifestyle in Orthocerida and a comparatively active, nektonic lifestyle in Bactritida and ammonoids. The new genus Acanthomichelinoceras is erected. Acanthomichelinoceras commutatum, Cycloceras sp., Bactrites gracile, Bactrites sp. A, Bactrites sp. B, and Bactrites sp. C are described.
Źródło:
Acta Palaeontologica Polonica; 2005, 50, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Benthic ostracods from the Early-Middle Frasnian transition in the north-western East European Platform, Russia
Autorzy:
Evdokimova, I O
Powiązania:
https://bibliotekanauki.pl/articles/21796.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
benthic ostracod
ostracod
Early-Middle Frasnian
Frasnian
paleontology
East European Platform
Russia
Ostracoda
Main Devonian Field
Opis:
Pronounced changes in benthic ostracod associations in the north−west part of the East European Platform, across the Early–Middle Frasnian (Devonian) transition, track a marine transgression event. More than 80 ostracod species belonging to the Eifelian Mega−Assemblage were recorded. Cavellinidae and Acratiidae generally dominate the Early Frasnian Sargaevo Horizon. Middle Frasnian ostracod associations of the Semiluki Horizon are more diverse and are characterised by different dominant both geographically and stratigraphically, resulting from significant palaeo−basin bottom relief and benthic biotope differentiation. The ostracod associations are indicative of very shallow, well oxygenated semi−restricted epeiric environment, with occasional marine influence, alternating with short periods of open shelf conditions. The relative abundance of ostracod species in the different associations, and faunal diversity indices, show considerable variations throughout the Early–Middle Frasnian, and suggest a less restricted position within an intra−platform setting in the Middle Frasnian, relative to a more restricted ostracod habitat in the Early Frasnian. The succession of Early–Middle Frasnian micro−benthic associations within the Main Devonian Field seems to be of a regional scale, and resulted from a marine regression−transgression couplet, corresponding to eustatic cycles IIb–IIc. This was paired with synsedimentary tectonic subsidence in adjacent areas of the north−east East European Platform, progressively improving marine water circulation in the extremely shallow−water shelf seas.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 4; 773-778
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Early and Middle Frasnian brachiopod faunas and turnover on the South China shelf
Autorzy:
Ma, X -P
Becker, R.T.
Li, H.
Sun, Y.-Y.
Powiązania:
https://bibliotekanauki.pl/articles/21029.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Early Frasnian
Middle Frasnian
Frasnian
paleontology
brachiopod fauna
South China shelf
Devonian
Brachiopoda
Cyrtospirifer
faunal turnover
Opis:
The first appearance of the brachiopod Cyrtospirifer and related forms in the Late Devonian of South China significantly postdates the beginning of the Frasnian and the entry of the group in other parts of the world. Scattered data from different sections suggest that its first entry, associated with the emergence of other plicate spiriferids, such as theodossid and conispiriferid brachiopods, was late in the Middle Frasnian. At the same time, many rhynchonellids disappeared or became extinct locally in South China. This brachiopod faunal overturn near the Palmatolepis punctata–Early Pa. hassi zonal boundary is the most significant event in the Early–Middle Frasnian of South China, characterized by about a 35% loss of existing species and the flourishing of the plicate spiriferids, which was coeval with the end of a major biogeochemical perturbation recently recognized in the Pa. punctata Zone. By contrast, atrypid brachiopods do not seem to show any significant diversity change. The brachiopod faunal change was probably related to a (local?) transgressive event in South China, which also brought new pelagic faunas northwards into some intra−shelf deeper water areas, such as the Shetianqiao area in central Hunan Province. Fifteen brachiopod species are described and illustrated, which include some taxa that are first recorded or recognized in South China, e.g., the spiriferid Pyramidaspirifer, which is now known from both North America and South China. One new species, Desquamatia qiziqiaoensis, is erected.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 4; 789-812
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Early Frasnian acanthodians from Central Iran
Autorzy:
Hairapetian, V.
Valiukevicius, J.
Burrow, C.J.
Powiązania:
https://bibliotekanauki.pl/articles/20209.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Acanthodii
Central Iran
Climatiidae
dental element
Diplacanthidae
Early Frasnian
Frasnian
Iran
Ischnacanthiformes
acanthodian
paleontology
histology
Devonian
systematics
Opis:
Two vertebrate−bearing horizons in the basal Frasnian carbonate of the Chahriseh section, northeast of Esfahan, yielded microremains of thelodonts, placoderms, acanthodians, actinopterygians, chondrichthyans, and sarcopterygians, considerably expanding the vertebrate faunal list for the strata. Acanthodians comprise a diverse association of climatiids, diplacanthids, and ischnacanthiforms, including the previously recorded climatiid Nostolepis sp. cf. N. gaujensis, as well as one new climatiid genus and several taxa left in open nomenclature. Climatiid Iranolepis ginteri gen. et sp. nov. is diagnosed by having scales with a highly raised medial crown area separated by steep slopes from lateral crown areas; an odontocytic mesodentine of maximum extent in the crown, distinguished by extensive network of fine canaliculi with abundant tiny osteocytes; and a poorly developed stranggewebe system. Other scales with fan−like symmetrically grooved crowns conform to the Diplacanthus−type histologically, and have many characters in common with Milesacanthus antarctica from the Aztec Siltstone of Antarctica. Osseous gnathal elements include mesodentinous tooth whorls from an ischnacanthiform or climatiid, and ischnacanthiform jaw bones with large chambers for vascular canals, distinctly separated cylindrical tooth cusps along the lingual ridge, and wide−based, triangular, weakly striated cusps on the main lateral ridge. The acanthodian association, accompanied by the Frasnian conodonts of the middle Mesotaxis falsiovalis to Palmatolepis hassi zones and zonal thelodonts Turinia hutkensis and Australolepis seddoni, is proving useful for biostratigraphy, showing similarities with assemblages from both Gondwana and the Old Red Sandstone Continent.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Faunal and facies changes at the Early-Middle Frasnian boundary in the north-western East European platform
Autorzy:
Zhuravlev, A V
Sokiran, E.V.
Evdokimova, I.O.
Dorofeeva, L.A.
Rusetskaya, G.A.
Malkowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/20261.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
fauna change
Early-Middle Frasnian
East European Platform
Conodonta
Brachiopoda
Ostracoda
correlation
carbon isotope
Frasnian
Main Devonian Field
Opis:
Multidisciplinary study of the Early–Middle Frasnian boundary in the north−western East European Platform (Main Devonian Field) allows evaluation of changes in facies, brachiopod, ostracod, and conodont associations, as well as carbon isotope composition. Brachiopod and ostracod faunas, characterized by predominance of rhynchonellids, spiriferids, podocopids, and platycopids in the Early Frasnian, and by predominance of spiriferids, palaeocopids, and kloedenellocopids in the Middle Frasinan, demonstrate significant changes in dominance and diversity likely caused by regressiontransgression couplets in the extremely shallow−water environment. Changes in diversity of the conodont associations, represented mainly by shallow−water polygnathids and spathognathids, are controlled by sea−level fluctuations as well; however significant evolutionary turnover is absent. Deepening pulses lead to an increasing in diversity of both the benthic and nectic groups, whilst regressions cause diversity fall due to progressive habitat reduction. Most prominent decreasing in the fauna diversity is observed in the late Early Frasnian (Dubnik time) coinciding with the regressive phase of the Late Givetian to Early Frasnian eustatic cycle. Positive−negative δ¹³C excursion, detected in brachiopod calcite from the early interval of the Middle Frasnian, can be correlated with global isotopic perturbations near the Frasnian substage boundary: the positive 2.6‰ δ¹³C excursion is probably linked with enhanced primary production in high−nutrient regimes in the epeiric sea.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 4; 747-758
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conodont-based event stratigraphy of the Early-Middle Frasnian transition on the South Polish carbonate shelf
Autorzy:
Pisarzowska, A
Sobstel, M.
Racki, G.
Powiązania:
https://bibliotekanauki.pl/articles/22673.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
conodont association
stratigraphy
Early-Middle Frasnian
Frasnian
Polska
carbonate shelf
biostratigraphy
carbon isotope
paleoecology
Devonian
Palmatolepis transitans
Palmatolepis punctata
Opis:
Early to Middle Frasnian (E–MF) epicontinental sequences are investigated in five representative localities of the Holy Cross Mountains and Cracow region, with emphasis on conodont biostratigraphy, to evaluate the regional stratigraphic and biotic context of a major biogeochemical perturbation in global carbon cycling. Conodont associations from the Palmatolepis transitans to Palmatolepis punctata Zone boundary beds are dominated by the shallow−water polygnathid and ancyrodellid fauna in the South Polish epicontinental successions, and first appearances of index palmatolepid species are delayed due to facies control of pelagic environments during intermittent drowning of the carbonate shelf. Thus, identification of the zonal boundary is based mainly on species of Ancyrodella, and five distinctive ancyrodellid levels in the succession across the E–MF interval enable refined correlation of the sections studied, especially when paired with chemostratigraphic proxies. Prominent conodont biofacies shifts coincided with eustatic deepening, which is correlated with the Timan, Middlesex, and early Rhinestreet events, respectively. Trends in the conodont dynamics, mortality and diversity, partly replicated by the benthic biota (especially shelly faunas and crinoids), indicate that the faunal turnovers correlate also with the main δ¹³C excursions and related changes in trophic conditions. The E–MF transitional interval, marked by short−term sea−level fluctuations, is distinguished by a change from relatively diversified biofacies to more homogenous, mostly impoverished faunas. The latter change is a biotic response to the beginning of a prolonged (ca. 0.5 Ma) positive δ¹³C anomaly, probably paired with unsteady eutrophic and partly anoxic regimes. The late Pa. punctata Zone negative carbon isotope anomaly is synchronous with the second large−scale pelagic biofacies remodelling, including mesotaxid extinction. A stabilization of the carbon cycle and its return to normal background values at the start of the Early Palmatolepis hassi Zone coincide with conodont biofacies diversification and recovery of reef−related biofacies. With the exception of collapsed, endemic Kadzielnia−type mud−mound biota and a moderate biodiversity depletion due to overall ecosystem stagnation, no significant extinction events can be demonstrated, even if the large−scale changes in carbon cycling during the E–MF timespan are of higher−amplitude than the celebrated carbon isotopic anomalies related to the Frasnian–Famennian mass extinction. Thus, this regional succession in detail confirms that the large−scale punctata Isotopic Event (= Pa. punctata Event) is correlated neither with catastrophic enviromental nor radical biotic changes.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 4; 609-646
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gastropod succession across the Early-Middle Frasnian transition in the Holy Cross Mountains, southern Poland
Autorzy:
Krawczynski, W
Powiązania:
https://bibliotekanauki.pl/articles/21568.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
gastropod succession
Early-Middle Frasnian
Frasnian
transition
Holy Cross Mountains
Southern Poland
Polska
Gastropoda
Eotomariidae
Elasmonematidae
bioevent
Devonian
Opis:
Gastropod response to a marked carbon isotopic geochemical anomaly across the Early–Middle Frasnian transition (Palmatolepis transitans–Palmatolepis punctata conodont zones) has been analysed along the southern Laurussian shelf, mainly within the Dyminy Reef in the Holy Cross Mountains. Gastropods are represented by three reefal associations (Kowalatrochus sanctacrucensis, Euryzone kielcensis, and Grabinopsis guerichi associations), and an impoverished open−shelf Straparollus laevis assemblage. The most severe diversity crisis is connected to the disappearance of local low−energy muddy habitats, as a result of a transgressive pulse (Middlesex Event) and benthic habitat changes tied to strongly fluctuating carbon cycling; this has been observed at the highly diverse Kadzielnia−type assemblage. Fifteen taxa have been recognised in this distinctive Early Frasnian mud−mound association, including six (probably endemics), which are unknown from the Middle Frasnian. The disappearance of three relict Givetian species (Euryzone delphinuloides, Straparollus laevis, and Goniasma? zarecznyi) is also recorded. Other species probably migrated into the shallower water part of Dyminy Reef and persisted in the Middle and Late Frasnian. The Middlesex Event and the earlier major biogeochemical perturbation seem to have less serious effects for evolution of gastropods in the Polish−Moravian part of the Laurussia shelf than the catastrophic Frasnian–Famennian extinction. Two new taxa are described: Frydiella kaimi gen. et sp. nov. (Eotomariidae) and Heidelbergeria czarnieckii gen. et sp. nov. (Elasmonematidae).
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 4; 679-693
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vascular structure of the earliest shark teeth
Autorzy:
Martínez-Pérez, C.
Martín-Lazaro, A.
Ferrón, H. G.
Kirstein, M.
Donoghue, P. C. J.
Botella, H.
Powiązania:
https://bibliotekanauki.pl/articles/139170.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Leonodus
Celtiberina
early chondrichthyans
Lower Devonian
synchrotron tomography
vascular system
ryby chrzęstnoszkieletowe
ryby chrzęstne
chrzęstniki
dolny dewon
tomografia
układ naczyniowy
Opis:
Here we use synchrotron tomography to characterise dental vasculature in the oldest known tooth-bearing sharks, Leonodus carlsi Mader, 1986 and Celtiberina maderi Wang, 1993. Three dimensional reconstruction of the vascular system and microstructure of both taxa revealed a complex and dense network of canals, including horizontal, ascending and secondary bifurcated canals, as well as histological features consistent with an osteodont histotype. However, L. carlsi and C. maderi also exhibit significant morphological differences, showing Leonodus a typical diplodont tooth morphology with a linguo-labially elongated base, that contrast with Celtiberina’s teeth that show a single conical cusp curved lingually with a week developed flat base mesio-distally extended, perhaps reflecting distant relationship. These data are compatible with a pre-Devonian diversification of the two main tooth types traditionally recognised in Palaeozoic sharks (i.e., “cladodont” vs “diplodont”). Finally, our data demonstrate that existing dental classification schemes based on styles of vascularisation are over-simplified, especially when Palaeozoic taxa are considered.
Źródło:
Acta Geologica Polonica; 2018, 68, 3; 457-465
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Molluscs from the Early Frasnian goniatite level at Kostomloty in the Holy Cross Mountains, Poland
Autorzy:
Jagt-Yazykova, E
Krawczynski, W.
Rakocinski, M.
Powiązania:
https://bibliotekanauki.pl/articles/20723.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
mollusc
Early Frasnian
Frasnian
goniatite level
Kostomloty commune
Holy Cross Mountains
Polska
Devonian
Goniatitida
Nautiloida
Gastropoda
Bivalvia
paleoecology
Acanthoclymenia
Linguatornoceras
Koenenites
new species
Palaeozygopleura pyritica
bivalve
Glyptohallicardia multicostata
Opis:
The unique goniatite−rich pyritic level, 1.6 m thick, exposed at Kostomłoty (Holy Cross Mountains, central Poland) represents a distinct, local biotic event in the Early Frasnian interval corresponding to the inception of a major geochemical (carbon cycling) perturbation in the stagnant deep−water and oxygen−deficient Kostomłoty basin. The taxonomic and palaeoecologic characteristics of molluscan fossil associations from the Goniatite Level are presented. Most of the goniatitids and orthoconic nautiloids from the studied fossil assemblages are juvenile conchs or protoconchs, or incomplete phragmocones and represent the genera Acanthoclymenia and Linguatornoceras, the former being predominant, and a single adult specimen probably of the genus Koenenites. In contrast, gastropods and bivalves are generally well preserved and identifiable to species level. Two new species are described: a gastropod Palaeozygopleura (Bohemozyga) pyritica sp. nov. and a bivalve Glyptohallicardia multicostata sp. nov. These studied molluscs and also amphiporoids are allochthonous elements which must have been transported into the deeper settings during sea−level rise and flooding of fringing reefs (Timan Event) and/or storm events, and there were mixed with pelagic cephalopods. Probably, a sea−level rise even led to flooding of nearby areas, and thus to introduction of pelagic material (juvenile cephalopods) into reefal settings, and then back to the deeper water again by the quasi−estuarine circulation of water masses.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 4; 707-718
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-13 z 13

    Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies