Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 23

Liczba wyników na stronie
first rewind previous Strona / 2 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  Famennian
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 2 next fast forward last
EN
Very rare chondrichthyan spines from the Famennian (Upper Devonian) of European Russia are referred here to ctenacanthiforms, euselachians and a chondrichthyan group of uncertain systematic position. Ctenacanthus Agassiz, 1837 is recorded from the lower and middle Famennian of the central and north-western parts of the area. Sculptospina makhlaevi Lebedev gen. et sp. nov. originates from the lower Famennian of the Lipetsk Region. The holotype of ‘Ctenacanthus’ jaekeli Gross, 1933 and a new specimen from the upper Famennian of the South Urals are shown to belong to the same taxon, which is transferred to Acondylacanthus St. John and Worthen, 1875. New specimens of Tuberospina nataliae Lebedev, 1995 from the upper Famennian of Central Russia are described in detail. The newly presented material increases our knowledge of the composition of Famennian marine assemblages from the East European Platform. It is suggested that these assemblages may be classified as chondrichthyan-dominated and dipnoan-dominated. Hypothetically, after the end- Devonian Hangenberg extinction event, which affected numerous secondary consumers in vertebrate communities, some chondrichthyan groups could have encroached to take advantage of previously occupied ecological niches. Ctenacanthus, as well as Acondylacanthus and Amelacanthus survived the end-Devonian mass extinction to continue into the Carboniferous.
EN
The Shotori Range of east-central Iran (east of Tabas) has yielded Famennian ammonoid assemblages dominated by the family Sporadoceratidae. Four genera Maeneceras Hyatt, 1884, Iranoceras Walliser, 1966, Sporadoceras Hyatt, 1884 and Erfoudites Korn, 1999 are represented. The conodont assemblage of one sample containing Iranoceras revealed an Upper marginifera Zone age. The ammonoid assemblages are characterised by comparatively large specimens; they reach conch diameters of 300 mm (including the body chamber) and the mean size is larger than 100 mm. The preservation of the material from the Shotori Range and size comparison with sporadoceratid assemblages from the Anti-Atlas of Morocco and the Rhenish Mountains of Germany suggest that hydraulic sorting has resulted in a bias towards large conchs, explaining the size distribution, rather than latitudinal differences. The new species Maeneceras tabasense is described; the genus Iranoceras is revised with a new description of the two species Iranoceras pachydiscus (Walliser, 1966) and Iranoceras pingue (Walliser, 1966).
EN
Newly collected and restudied earlier materials on an enigmatic fish Ventalepis ketleriensis Schultze, 1980 from the upper Famennian (postera – ? Lower expansa conodont zones) of Latvia and central and northwestern Russia support its porolepiform affinities. A new family Ventalepididae fam. nova is established for this genus upon a peculiar combination of characters, including scale structure and dermal bones ornamentation. New records extend the distribution of this genus and the Ventalepis vertebrate assemblage on the whole to a vast geographical zone along the south-eastern coast of the Old Red Sandstone continent. The habitat area of the Devonian vertebrate assemblage over such a large territory within the zoogeographical province of Baltica is established for the first time. Palaeozoogeographical analysis suggests Laurentian affinities of the Ventalepis assemblage demonstrating the major congruency to the Belgian and East Greenland ones. These and Russian localities are separated by a vast ORS continent. Presence of the dipnoan Jarvikia in all three locations, as well as an Ichthyostega-like tetrapod in the Belgian one reveals palaeozoogeographical connections, which might reflect possible dwelling not only in the near-shore continent periphery but also in the river systems of the continent itself.
EN
Six enigmatic fossils from the Famennian (Devonian) Cleveland Shale in Ohio, U.S.A., are interpreted here as arthrodiran (Placodermi) egg cases. Recognition as egg cases is confirmed based on the observation of layered collagen fibers. The presence of a tuberculated bone fragment preserved within one case confirms a vertebrate source. The nature of the tubercles and the unique morphology of the egg cases supports the interpretation of an arthrodiran source. Reports of Devonian egg cases are limited to either assumed chondrichthyan producers or a putative ‘egg sac’ with a morphology atypical for any vertebrate. The Cleveland Shale egg cases thus represent the first record for a non-chondrichthyan producer. Among placoderms, behaviors of a pelagic life style with obligate nesting sites, reef fishes with live birth, and estuarine and fluvial nurseries, along with eggcase oviparity testifies to the diversity of reproductive strategies. As with modern fishes these strategies may be ecologically driven and the derived and variable reproductive biology of extant chondrichthyans is actually a primitive condition among gnathostomes. One consequence of the diversity of reproductive strategies (dependent on the topology of relationships) is the independent origin of internal fertilization within placoderms, possibly suggesting external fertilization as the primitive gnathostome reproductive mode.
EN
The Cleveland Shale fauna represents a unique view of the time after a major Devonian extinction event (Frasnian–Famenian) with the recovery of arthrodires (Placodermi) best represented by this most specious North American fauna. This time was followed by an additional event (Hangenberg Biocrisis) leading to the extinction of arthrodires (and all other placoderms). An understanding of the diversity and interrelationships of North American arthrodires can aid our understanding of this critical time in vertebrate evolution. A new aspinothoracid arthrodire Hlavinichthys jacksoni gen. et sp. nov. is described from the Late Devonian of northern Ohio, U.S.A., which adds to our knowledge of this group. It provides a point of comparison to other members of the fauna whose interrelationships are poorly known. A phylogenetic analysis supports an assignment of Hlavinichthys jacksoni gen. et sp. nov. among the aspinothoracid arthrodires. This work has drawn attention to the continued need for descriptive and phylogenetic analyses of this unique fauna. Decades old species descriptions need revision along with preparation and description of new taxa. The work on Hlavinichthys jacksoni gen. et sp. nov. here is one step in that process.
EN
The first tetrapodomorph specimen from the Palaeozoic sequences of the Moravian Karst (Moravo-Silesian Basin, Bohemian Massif, Czech Republic) is described. The well preserved, cosmine-covered lateral extrascapular bone comes from the Upper Devonian (Famennian) hemipelagic Křtiny Limestone of the Líšeň Formation. The affinity to the “osteolepiforms” is inferred from the cosmine histology and morphological features of the bone. Assignment to the Megalichthyiformes seems most probable. The associated fauna, e.g., clymenids, orthocone nautiloids, thin shelled bivalves, trilobites and crinoids, clearly demonstrate a marine environment.
EN
A diverse microvertebrate fauna is described from the Virgin Hills and Napier formations, Bugle Gap Limestone Canning Basin, Western Australia. Measured sections at Horse Spring and Casey Falls (Virgin Hills Formation) and South Oscar Range (Napier Formation) comprise proximal to distal slope carbonates ranging in age from the Late Devonian Frasnian to middle Famennian. A total of 18 chondrichthyan taxa are identified based on teeth, including the first record of Thrinacodus tranquillus, Cladoides wildungensis, Protacrodus serra and Lissodus lusavorichi from the Canning Basin. A new species, Diademodus dominicus sp. nov. is also described and provides the first record of this genus outside of Laurussia. In addition, the upper range of Australolepis seddoni has been extended to Late Devonian conodont Zone 11, making it the youngest known occurrence for this species. The Virgin Hills and Napier formations microvertebrate faunas show close affinities to faunas recovered from other areas of Gondwana, including eastern Australia, Iran, Morocco and South China, which is consistent with known conodont and trilobite faunas of the same age.
EN
A single perfectly preserved colony of a tabulate coral assigned tentatively to the genus Yavorskia Fomitchev, 1931, collected from Upper Famennian beds (Palmatolepis expansa conodont Zone) in a trench located north of the Kowala Quarry (Holy Cross Mts., central Poland) is here described as a new species, ?Y. paszkowskii sp. nov. It differs from other representatives of the genus in the lack of dissepimental structures and in smaller corallite diameters, and may therefore represent the ancestral taxon of this typically early Carboniferous genus. Yavorskia tabulates were apparently migrating eastwards along the southern margin of Laurussia and farther east and north towards Siberia, as they appear in the Famennian in Europe and in the early Carboniferous in the Altaides. Such a conclusion is consistent with previous observations on Early.Middle Devonian pleurodictyform tabulate distribution.
EN
Five species of the Late Famennian family Balviinae korn 2002, Effenbergia lens korn, 1992, E. minutula korn, 1992, Kenseyoceras nucleus (schmidt, 1924), K. biforme (schindewolf, 1937), and Balvia globularis (schmidt, 1924), are described from the Holy Cross Mountains, Central Poland. The material comes from the "Wocklumeria Beds" of the kowala, ostrówka and Besówka sections, possibly from the Effenbergia lens - Parawocklumeria paradoxa zones and from the upper part of the Wocklumeria sphaeroides Zone - Epiwocklumeria applanata subzone of the Late Famennian.
10
EN
The upper part of the Woodward Shale of southern Oklahoma has yielded the first moderately diverse North American ammonoid fauna from the uppermost Famennian (Upper Devonian VI). It includes six species from three clymeniid and one goniatite family: Kielcensia vagabunda sp. nov., Riphaeoclymenia polygona sp. nov., R. pontotocensis sp. nov., Cyrtoclymenia cf. procera Czarnocki, 1989, Spirosporadoceras overi gen. nov. sp. nov., and a poorly preserved different juvenile sporadoceratid that may represent a second new genus. For comparison, the related Spirosporadoceras delicatum sp. nov. from Germany is described. Kielcensia specimens from Oklahoma represent the first uncontested record of triangularly coiled wocklumeriids from North America. Together with Riphaeoclymenia, the Oklahoma fauna has similarities and strong biogeographical ties with the far distant Holy Cross Mountains of Poland. Kielcensia and Riphaeoclymenia are missing from the diverse contemporaneous ammonoid faunas of Middle and Southern Europe, which were located between the Oklahoma and the Polish occurrences. Geographically intermediate contemporaneous Moroccan faunas also show a fundamentally different composition but the Afro-Appalachian migration route must have been viable in the uppermost Famennian. Migrations through regions without leaving a trace in available very rich fossil records ("ghost distributions") create a bias for the palaeobiogeographical analysis of nektonic organisms. The faunal composition of the Woodford Shale suggests a control of ammonoid distribution patterns by palaeoecological factors that are not recognizable in the lithofacies.
EN
An assemblage of fifteen taxa of chondrichthyan microremains from late Frasnian through late Famennian pelagic deposits of the Kale Sardar section, eastern Iran, is described. Several taxa (Phoebodus bifurcatus, Phoebodus sophiae and Protacrodus vetustus) are reported for the first time from Iran. The presence of Deihim mansureae and Ph. sophiae in the Late rhenana to linguiformis Zones and Phoebodus rayi in the early triangularis Zone of the Kale Sardar section, provides new biostratigraphic information. The late Frasnian part of the assemblage corresponds to the faunas from the intrashelf basins of central europe, and the middle.late Famennian part is comparable to that from the tafilalt Platform of Morocco.
EN
"Sheltered preservation" of various organisms within shells of cephalopods is a well-known phenomenon and numerous examples have been frequently reported by paleontologists from several regions but so far not from Poland. In the present paper, spectacular examples of such occurrences of different organisms preserved mainly within empty cephalopod shells are reviewed. Moreover, specimens of trilobites representing the genus Cyrtosymbole, found within the phragmocone of a clymeniid ammonoid Kalloclymenia, and disarticulated fragments of trilobites preserved in body chamber of an orthoconic nautiloid are illustrated and shortly described from the Upper Famennian of Kowala (Holy Cross Mountains, Poland).
EN
An assemblage of blind phacopid trilobites of the genus Trimerocephalus McCoy, 1849, representing either the species Trimerocephalus mastophthalmus (Reinhard Richter, 1856) or its allies (possibly, a new species), from an Early Famennian (Early Marginifera Zone) marly sequence of the Holy Cross Mountains, Central Poland, is composed of well organized single-file queues. The trilobites in the queues appear almost intact, having been preserved in the position they kept when forming the queues, and are interpreted showing migratory behaviour known in various present-day arthropods, but unreported from the fossil state. This queuing was induced by environmental stress caused by a dramatic drop in sea level, temporarily leading to emersion. The preservation of the queues at omission horizons is thus ascribed to a mass mortality event, caused by subaerial exposure. The trilobites were suffocated and fossilized in a mortal spasm, and finally blanketed by calcareous ooze when inundated at a highstand. The assemblage of trilobite queues represents a unique example of frozen behaviour and a snapshot of the geological past.
14
Content available remote Famennian chondrichthyan remains from the Chahriseh section, central Iran
EN
A diverse shallow water assemblage of chondrichthyan microremains is described from the Famennian of the Chahriseh section, central Iran. Twenty-two taxa are identified; of these two new taxa viz. Roongodus phijani gen. et sp. nov. (Hybodontoidea) and Arduodens flammeus gen. et sp. nov. (Ctenacanthiformes) have been erected. Two morphoecological subtypes of Ph. gothicus dentition, characteristic of deeper and shallower shelves, are proposed.
EN
Tabulate corals are sometimes associated with other organisms occurring within their skeletons. These tabulate endobionts are common in Lower Palaeozoic (Ordovician and Silurian) and Devonian strata, but until now they have not been recognized in strata younger than early Frasnian. Here we report ?Chaetosalpinx sp. occurring within the skeletons of the tabulate coral Yavorskia sp. (Favositida, Cleistoporidae) from the latest Famennian ("Strunian") in the Etroeungt area (Northern France). It can be stated that these endobionts survived the Frasnian-Famennian boundary crisis and recovered in the Late Famennian.
PL
W niniejszej pracy opisano faunę amonitową z najwyższego famenu (górny dewon) odsłaniającego się w kamieniołomie Kowala. Obejmuje ona 31 taksonów. Po raz pierwszy z Kowali opisano dwa gatunki amonitowatych: Prionoceras frechi (Wedekind, 1913) oraz Flexiclymenia tempestiva (Czarnocki, 1989). Ponadto omówiono na podstawie własnych obserwacji oraz starszych prac faunę towarzyszącą. Przedstawiono interpretację paleoekologiczną poziomu klimeniowego. Na podstawie fauny amonitowej ustalono pozycję stratygraficzną badanego poziomu. Obejmuje on zony od Clymenia laevigala po Wocklumeria sphaeroides, odpowiadające górnej części zony konodontowej expansa i dolnej części zony konodontowej praesulcata.
EN
This paper discusses ammonoid fauna from Uppermost Famennian (Upper Devonian) in Kowala Quarry, which includes 31 taxa. For the first time two ammonoid species Prionoceras frechi (Wedekind, 1913) and Flexiclymenia tempestiva (Czarnocki, 1989) have been described from this locality. In addition, the paper summarizes taxonomic characteristics of the fossil assemblage, as well as the environmental reconstruction of the Clymeniide Level. The stratigraphic setting of this unit has been determined with ammonoids. The level includes the following zones: Clymenia laevigata and Wocklumeria sphaeroides, corresponding to the units of conodont zones: upper expansa and lower praesulcata.
EN
Coelacanth fishes from the Upper Devonian of the Holy Cross Mountains, Poland, are described. The material consists of isolated incomplete lower jaws, gular plates, an entopterygoid and urohyal. The isolated lower jaws belong to Diplocercides kayseri (VON KOENEN, 1895). The other coelacanth remains are referred to Diplocercides sp. indet. All specimens are Famennian in age (Early Palmatolepis rhomboidea conodont Zone), representing a time when almost all of the Holy Cross Mountains carbonate platform was drowned. Because of the shallow-water living conditions preferred by the group it is assumed that these coelacanths were restricted to isolated, small submarine swells, which still existed in that region in the latest Devonian, and that their carcasses were then subjected to post-mortem transport into the deeper areas.
18
Content available remote Nowe dane na temat flory z famenu Gór Świętokrzyskich
EN
New macroflora remains were found from the Famennian strata (unit J) from the Kowala Quarry (the Holy Cross Mts., central Poland). Palynological research indicates presence of the VF (Diducites versabilis-Grandispora famenensis) miospore Zone. Macroflora is very well preserved as many carbonized parts or imprints. Preliminary observations indicate that those remains can belong to genus Archaeopteris. This cosmopolitan genus has been earlier reported from Poland in the Sudetes Mts. from similar stratigraphic position.
EN
A revision of a major part of the old collections of Upper Devonian goniatites from the Holy Cross Mts., collected by J. Czarnocki, H. Makowski and M. Różkowska, is presented. Described and illustrated are 26 species and subspecies belonging to 20 genera and subgenera and 9 families. Studied and illustrated for the first time are 35 suture lines and 15 growth lines. Conodonts, mostly collected from the parent rocks of the studied goniatites, allow for a more precise correlation of these goniatites with standard ammonoid and conodont zonations. The museum collections studied incude specimens mostly of all standard Upper Frasnian through Famennian ammonoid zonations, but the precise zonal boundaries could not be established. Goniatite assemblages from the Płucki and Janczyce sections correspond to the linguiformis and Upper crepida conodont zones, respectively. Moreover, four conodont zones have been distinguished in the Łagów (Dule) section: Upper crepida/rhomboidea, Lower marginifera, Lower/Upper marginifera and trachytera zones. This last zone has been recognised here for the first time.
EN
The mid-Late Devonian pelagic sedimentary successions of the Rhenish Mountains and other regions show a double black shale horizon called the annulata Black Shale. It marks, at the species level, a prominent faunal turnover of ammonoids from the Prolobites delphinus Zone into the Platyclymenia annulata Zone. An analysis of ammonoid genera distribution, phylogenetic relationships, andmorphospace occupation demonstrates that the "annulata Event" does not correspond to a crisis of the group and does not fulfill the criteria of a major biotic event.
first rewind previous Strona / 2 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.