Informacja

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

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "Lower Cambrian" wg kryterium: Wszystkie pola

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 39
Tytuł:
The lobopod Onychodictyon from the Lower Cambrian Chengjiang Lagerstatte revisited
Autorzy:
Liu, J
Shu, D.
Han, J.
Zhang, Z.
Zhang, X.
Powiązania:
https://bibliotekanauki.pl/articles/21235.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Yunnan
antenna
paleontology
Chengjiang Lagerstatte
Lobopodia
Arthropoda
lobopod
Cambrian
Lower Cambrian
Opis:
Onychodictyon ferox, from the Lower Cambrian Chengjiang Lagerstätte, is a worm−like armored lobopod with 10 pairs of dorsal plates and a pair of probable sensory appendages (“antennae”). Newly discovered complete specimens show that Onychodictyon is represented by two species: O. ferox with a “head” bearing a pair of dorsal “antennae” and a trunk with 11 pairs of limbs, whereas O. gracilis has a blunt anterior end without any appendages and a trunk with 12 pairs of limbs. Because of the close resemblance of the “antennae” of O. ferox and those of the lobopod Miraluolishania, they are considered to be homologous structures. The “antennae” of Cambrian lobopodians are proposed to be homologous with the arthropod antennulae.
Źródło:
Acta Palaeontologica Polonica; 2008, 53, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lower Cambrian trace fossils from the Holy Cross Mountains, Poland
Autorzy:
Orłowski, S.
Żylińska, A.
Powiązania:
https://bibliotekanauki.pl/articles/2059927.pdf
Data publikacji:
2002
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Holy Cross Mountains
Lower Cambrian
trace fossils
Opis:
Additional data on the Lower Cambrian ichnotaxa from the Holy Cross Mountains are presented. Nine ichnotaxa are described for the first time from the area, additional descriptions of three known ichnotaxa are supplied, and two ichnotaxa are shown to have extended stratigraphic ranges. Most Lower Cambrian trace fossils belong to the Cruziana ichnofacies. The high taxonomic diversity of the Early Cambrian trace fossil assemblages from the Holy Cross Mountains in comparison to the trace fossil assemblages of the Mid- and Late Cambrian of the area is confirmed.
Źródło:
Geological Quarterly; 2002, 46, 2; 135-146
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The oldest brachiopods from the lower Cambrian of South Australia
Autorzy:
Topper, T.P.
Holmer, L.E.
Skovsted, C.B.
Brock, G.A.
Balthasar, U.
Larsson, C.M.
Stolk, S.P.
Harper, D.A.T.
Powiązania:
https://bibliotekanauki.pl/articles/22055.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
brachiopod
Cambrian
South Australia
Brachiopoda
Tommotiida
Paterinida
Askepasma
microstructure
morphology
shell
Arrowie Basin
Lower Cambrian
Australia
paleontology
Opis:
The morphology and organophosphatic shell structure of the paterinate brachiopod Askepasma is documented using new and previously collected specimens from the lower Cambrian of South Australia. Lack of adequately preserved material has seen the majority of paterinate specimens previously reported from South Australia referred to the genus Askepasma and treated under open nomenclature. Large collections of paterinates from the lower Cambrian Wilkawillina, Ajax, and Wirrapowie limestones in the Arrowie Basin, South Australia have prompted redescription of the type species Askepasma toddense and the erection of a new species, Askepasma saproconcha sp. nov. Askepasma saproconcha sp. nov. currently represents the oldest known brachiopod from the lower Cambrian successions in South Australia with a FAD in pre−trilo− bitic (Terreneuvian, Cambrian Stage 2, lower Atdabanian) strata in the basal part of the Wilkawillina and Wirrapowie limestones. Askepasma toddense predominantly occurs in Abadiella huoi Zone equivalent strata (Unnamed Cambrian Se− ries 2, Stage 3, middle–upper Atdabanian) in the upper part of the lower Wilkawillina, Wirrapowie, and Ajax limestones. The shell microstructure of Askepasma suggests a proximal stem group position within the Brachiopoda and similarities with tommotiid taxa provides further evidence that the ancestry of crown group brachiopods is firmly entrenched within the Tommotiida.
Źródło:
Acta Palaeontologica Polonica; 2013, 58, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The new stem-group brachiopod Oymurania from the lower Cambrian of Siberia
Autorzy:
Kouchinsky, A.
Holmer, L.E.
Steiner, M.
Ushatinskaya, G.T.
Powiązania:
https://bibliotekanauki.pl/articles/21826.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Brachiopoda
brachiopod
Oymurania
Mickwitzia
Micrina
Setatella
Lower Cambrian
Cambrian
Siberia
Opis:
A stem-group brachiopod, Oymurania gravestocki Ushatinskaya gen. et sp. nov. is described herein from the middle Atdabanian-lower Botoman Stages (-Cambrian Stage 3) of the Siberian Platform. The fossils were extracted from limestone beds of the Emyaksin, Perekhod, and Pestrotsvet formations as assemblages of disarticulated orthoconic to cyrtoconic porous shells in apatite preservation. The originally organophosphatic shells of Oymurania are externally similar to mitral sclerites (ventral valves) of the stem-group brachiopod Micrina, although no sellate-like sclerites, nor differentiated subapical area with apophyses were recognised in our material. The range of Oymurania shells with sub-central to posteromarginal apex is similar to that of ventral valves ofMickwitzia. Oymurania is also characterised by the system of radial and orthogonal canals open in pairs or triplets in small depressions or indentations of growth lamellae in the outer shell surface. The orthogonal (Micrina-Setatella type) and radial (horizontal setigerous tubes) canals are widespread among the early Cambrian stem-group brachiopods, such as Micrina, Mickwitzia, and Setatella. In addition to these canals, Oymurania exhibits a well-developed acrotretoid columnar microstructure, also known from Setatella. A broad subapical platform in cyrtoconic shells (presumably ventral valves) of Oymurania is interpreted homologous to the deltoid area in mitrals of Micrina and pseudointerarea/interarea in ventral valves of Setatella/paterinid brachiopods. Except with probable cell imprints and openings of orthogonal canals, no morphological differentiation was, however, reflected by the shell interior of Oymurania gravestocki. Being closely related to tannuolinids and mickwitziids, Oymurania complements the picture of diversification of the early Cambrian stem-group brachiopods that occurred in parallel with radiation of paterinids and other crow-group brachiopods on the Siberian Platform and worldwide.
Źródło:
Acta Palaeontologica Polonica; 2015, 60, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Soft-tissue preservation in the Lower Cambrian linguloid brachiopod from South China
Autorzy:
Zhang, Z
Han, J.
Zhang, X.
Liu, J.
Shu, D.
Powiązania:
https://bibliotekanauki.pl/articles/20001.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Lingulellotreta malongensis
Chengjiang Lagerstatte
soft tissue preservation
lophophore
brachiopod
linguloid brachiopod
China
Linguloidea
gastrointestinal tract
Cambrian
Lower Cambrian
paleontology
Opis:
The organization of the lophophore and the digestive system are recognized as two of the diagnostic characters in the definition of higher brachiopod taxa, and hence play a major role in their phylogenetic analysis, their structure, however, is very rarely fossilized. Here we describe and interpret specimens of the brachiopod Lingulellotreta malongensis, from the Lower Cambrian Chengjiang Lagerstätte (South China), one of the earliest known taxa of the Lingulellotretidae, in which lophophores and intact, U−shaped digestive tracts are extraordinarily well−preserved. The lophophore, with clearly preserved tentacles, corresponds to an early spirolophe developmental stage. The digestive tract consists of a mouth, esophagus, distended stomach, intestine and an anterior anus, and differs from that of the Chengjiang obolid Lingulella chengjiangensis by the presence of the dilated stomach and by the absence of a looped intestine as in Lingula. In addition, the relative sizes of the mantle and visceral cavities of Lingulellotreta malongensis also are described. These fossils demonstrate that by the Atdabanian brachiopods had already possessed advanced features, and suggest that a lophophore and a U−shaped intestine with an anterior anus are brachiopod plesiomorphies.
Źródło:
Acta Palaeontologica Polonica; 2004, 49, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A large xenusiid lobopod with complex appendages from the Lower Cambrian Chengjiang Lagerstatte
Autorzy:
Liu, J
Shu, D.
Han, J.
Zhang, Z.
Zhang, X.
Powiązania:
https://bibliotekanauki.pl/articles/21541.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Chengjiang Lagerstatte
Lobopodia
China
arthropod
Jianshanopodia decora
large lobopod
lobopod
body length
Arthropoda
Xenusiidae
Cambrian
paleontology
Lower Cambrian
Opis:
A large lobopod, Jianshanopodia decora gen. et sp. nov., with body length (excluding appendages) about 220 mm from the Lower Cambrian Haikou section, near Kunming, Yunnan, southwest China, shows a mixture of characters, including features of the lobopod Xenusion Pompeckj, 1927, e.g., a large cylindrical body with annulations, stout and strong lobopod appendages each bearing bases of serial tubercles, and of Aysheaia Walcott, 1911, i.e., a pair of large frontal appendages. This suggests that the new genus might be a connecting link between Xenusion and Aysheaia. Besides, Jianshanopodia shares some features with the Early Cambrian stem group arthropod Pambdelurion Budd, 1997, and Kerygmachela Budd, 1993, e.g., the pairs of mid−gut diverticula, the possible presence of tail fan, the mouth cone, the frontal pharyngeal structures and the pharynax are surrounded by the bases of the large frontal appendages. However, compared with a series of segmentally arranged, imbricating, paddle−shaped, movable lateral flaps of both Pambdelurion and Kerygmachela, Jianshanopodia possesses distinct complex appendages with tree−like or lamellate branches. The discovery of this rare transitional form not only throws new light on the early diversification of lobopods, and may also have significance with respect to the origin of arthropods.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hyoliths and small shelly fossils from the Lower Cambrian of North-East Greenland
Autorzy:
Malinky, J M
Skovsted, C.B.
Powiązania:
https://bibliotekanauki.pl/articles/21690.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Hyolitha
Orthothecida
fossil
Hyolithida
Bastion Formation
Greenland
Lower Cambrian
paleontology
Botomian
Opis:
The hyolith assemblage from the Lower Cambrian Bastion Formation of North−East Greenland is significant in that it contains several hyolith taxa that possess traits of both orders Hyolithida and Orthothecida. They possess morphological traits that seem to be characteristic of the ancestral forms of both groups. In addition, many hyolith taxa from this interval are globally distributed, supporting the notion that these fossils have potential as stratigraphic indicators. This assemblage contains genera and/or species seen in Australia, North America, the Siberian Platform, and South China. Hyoliths identified include the hyolithids Parkula bounites, Hyptiotheca karraculum, Microcornus eximius, M. petilus, Paracornus poulseni gen. et sp. nov., as well as Similotheca similis?, S. bastionensis sp. nov., and S. groenlandica sp. nov.; two opercula remain in open nomenclature. Orthothecids from this assemblage are one unnamed species each of Contitheca and Gracilitheca. Large, macro−sized hyoliths from the same formation described by Poulsen (1932) are mostly unidentifiable, although an operculum formerly identified as Hyolithes (Orthotheca) communis is reassigned to Hyptiotheca. Problematic organisms of uncertain affinity include Cupitheca holocyclata, Conotheca australiensis, an unnamed species of Coleolus, and the cap−shaped Cassitella baculata gen. et sp. nov. that may be an operculum of some as yet unknown organism. Missarzhevsky (1969) used Hyolithes(Orthotheca) bayonet var. groelandicus and H. (O.) bayonet var. longus as the basis for Lenatheca, but the specimens on which that genus is based are too poorly known for a proper diagnosis of Lenatheca.
Źródło:
Acta Palaeontologica Polonica; 2004, 49, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The sulphur and oxygen isotopic composition of Lower Cambrian anhydrites in East Siberia
Autorzy:
Peryt, T. M.
Hałas, S.
Kovalevych, V. M.
Petrychenko, O. Y.
Dzhinoridze, N. M.
Powiązania:
https://bibliotekanauki.pl/articles/2058955.pdf
Data publikacji:
2005
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Siberia
Lower Cambrian
evaporites
sulphur isotopes
oxygen isotopes
Opis:
Published sulphur and oxygen isotope age curves for the late Neoproterozoic-Early Cambrian time interval have been based on studies of sulphate intervals of the East Siberian salt giant. We report here on sulphur and oxygen measurements for sulphate dispersed in, or forming laminae in, the rock salt deposits in all Lower Cambrian basins of East Siberia. Sulphur isotope data for 26 samples of Lower Cambrian anhydrites from East Siberia range from +22.6 to +34.5‰. No difference was observed between different suites and between samples taken from anhydrite intercalations in rock salt and from water-insoluble residue in rock salt. Oxygen isotope data for 25 anhydrite samples range from +12.4 to +17.8‰, and thus δ18 O values have a smaller range of variation (5.5‰) than δ34 S (11.8‰) over the entire set of Lower Cambrian anhydrites. The great δ34 S variability observed in the Lower Cambrian of Siberia seems to reflect mixing of sulphates coming from the ocean and due to the riverine input. The lowest δ18 O values may indicate the input values from both the sources, whilst the highest value may result from isotope exchange between SO4 2- and water. Our results combined with data provided by previous workers could indicate a clear stratigraphic trend in δ34 S values, with a remarkable fall of ca. 9‰ in δ34 S value during the earliest Cambrian and then a slight rise in δ34 S values in the younger part of Early Cambrian. However, if only the highest values are taken, the measured values are compatible with seawater δ34 S 3 30‰ during the entire Early Cambrian. Sulphur isotopic composition of sulphate minerals did not be come heavier from the sulphate stage to ward the chloride stage.
Źródło:
Geological Quarterly; 2005, 49, 2; 235--242
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shelly fossils from the lower Cambrian White Point Conglomerate, Kangaroo Island, South Australia
Autorzy:
Betts, M.J.
Claybourn, T.M.
Brock, G.A.
Jago, J.B.
Skovsted, C.B.
Paterson, J.R.
Powiązania:
https://bibliotekanauki.pl/articles/22489.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
The lower Cambrian (Series 2) White Point Conglomerate (WPC) on Kangaroo Island, South Australia contains exotic clasts representing a diverse array of lithologies, including metamorphics, chert, sandstone, and abundant carbonates, notably archaeocyath-rich bioclastic limestone. Acetic acid digestion of the WPC bioclastic limestone clasts reveals a diverse shelly fauna. This assemblage includes abundant organophosphatic brachiopods such as Cordatia erinae Brock and Claybourn gen. et sp. nov., Curdus pararaensis, Eodicellomus elkaniformiis, Eohadrotreta sp. cf. E. zhenbaensis, Eoobolus sp., Kyrshabaktella davidii, and Schizopholis yorkensis. Additional shelly taxa include the solenopleurid trilobite Trachoparia? sp., the tommotiids Dailyatia odyssei, Dailyatia decobruta Betts sp. nov., Kelanella sp., and Lapworthella fasciculata, spines of the bradoriid arthropod Mongolitubulus squamifer, and several problematica, such as Stoibostrombus crenulatus and a variety of tubular forms. The upper age limit for the WPC is constrained by biostratigraphic data from the overlying Marsden Sandstone and Emu Bay Shale, which are no younger than the Pararaia janeae Trilobite Zone (Cambrian Series 2, Stage 4). The shelly fossil assemblage from the WPC limestone clasts indicates an upper Dailyatia odyssei Zone (= Pararaia tatei to lower P. janeae trilobite zones), equivalent to the Atdabanian–early Botoman of the Siberian scheme. This contrasts with the previously suggested late Botoman age for the limestone clasts, based on the diverse archaeocyath assemblage. The minor age difference between the WPC and its fossiliferous limestone clasts suggests relatively rapid reworking of biohermal buildups during tectonically-active phases of deposition in the Stansbury Basin.
Źródło:
Acta Palaeontologica Polonica; 2019, 64, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Trachyplax arctica, a new multiplated problematic fossil from the Lower Cambrian of North Greenland
Autorzy:
Larsson, C M
Peel, J.S.
Hogstrom, A.E.S.
Powiązania:
https://bibliotekanauki.pl/articles/20953.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Trachyplax arctica
fossil
paleontology
Lower Cambrian
Cambrian
North Greenland
Greenland
Trachyplax
Problematica
sclerite
scleritome
Multiplacophora
Paralledal Formation
Opis:
A new scleritome−bearing organism with eight sclerite types, Trachyplax arctica gen. et sp. nov., is described from the lower Cambrian Paralledal Formation of North Greenland. The originally calcareous sclerites are now silicified; no microstructures are preserved. The dominant sclerite type (A; maximum dimension 19.3 mm) is bilaterally symmetrical, strongly arched, with an oval shield showing co−marginal growth lines and a projecting rostrum with prominent radial ornamentation. A similar sclerite morphology can be identified in Silurian–Carboniferous multiplacophoran molluscs but the remaining sclerite types, which also display a combination of concentric and radial ornamentation, find no clear equivalents. Two models for scleritome reconstruction are presented, based on the relative abundance of the sclerites, but neither promotes a satisfactory assignment to a higher taxon. Despite the morphological dissimilarities, possibly reflecting the age discrepancy, reference to the Multiplacophora is most attractive and entails a substantial extension of the known geological range of that group.
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 3; 513-523
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New palaeoscolecidan worms from the Lower Cambrian: Sirius Passet, Latham Shale and Kinzers Shale
Autorzy:
Morris, S.C.
Peel, J.S.
Powiązania:
https://bibliotekanauki.pl/articles/23022.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
new worm
worm
palaeoscolecidan worm
Lower Cambrian
Sirius Passet
Latham Shale
Kinzers Formation
paleontology
Palaeoscolecida
Chalazoscolex
Xystoscolex
Cycloneuralia
Cambrian
Greenland
California
Pennsylvania
Opis:
Palaeoscolecidan worms are an important component of many Lower Palaeozoic marine assemblages, with notable occurrences in a number of Burgess Shale−type Fossil−Lagerstätten. In addition to material from the lower Cambrian Kinzers Formation and Latham Shale, we also describe two new palaeoscolecidan taxa from the lower Cambrian Sirius Passet Fossil−Lagerstätte of North Greenland: Chalazoscolex pharkus gen. et sp. nov and Xystoscolex boreogyrus gen. et sp. nov. These palaeoscolecidans appear to be the oldest known (Cambrian Series 2, Stage 3) soft−bodied examples, being somewhat older than the diverse assemblages from the Chengjiang Fossil−Lagerstätte of China. In the Sirius Passet taxa the body is composed of a spinose introvert (or proboscis), trunk with ornamentation that includes regions bearing cuticular ridges and sclerites, and a caudal zone with prominent circles of sclerites. The taxa are evidently quite closely related; generic differentiation is based on degree of trunk ornamentation, details of introvert structure and nature of the caudal region. The worms were probably infaunal or semi−epifaunal; gut contents suggest that at least X. boreogyrus may have preyed on the arthropod Isoxys. Comparison with other palaeoscolecidans is relatively straightforward in terms of comparable examples in other Burgess Shale−type occurrences, but is much more tenuous with respect to the important record of isolated sclerites. These finds from Greenland provide further evidence that palaeoscolecidans possessed a complex anterior introvert directly comparable to a number of priapulid−like taxa from other Burgess Shale−type assemblages. Although these palaeoscolecidans have been allied with the nematomorphs, molecular data in conjunction with our observations suggest that this hypothesis is untenable. Palaeoscolecidans and similar priapulid−like taxa are probably primitive cycloneuralians and as such may indicate the original bodyplan of this important group of ecdysozoans. In addition, we describe another sclerite−bearing fossil from the Sirius Passet Fossil−Lagerstätte that may be related to the cambroclaves.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new leanchoiliid megacheiran arthropod from the lower Cambrian Emu Bay Shale, South Australia
Autorzy:
Edgecombe, G.D.
Garcia-Bellido, D.C.
Paterson, J.R.
Powiązania:
https://bibliotekanauki.pl/articles/21269.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
new arthropod
arthropod
leanchoiliid megacheiran arthropod
Lower Cambrian
Cambrian
South Australia
paleontology
Arthropoda
Megacheira
Leanchoiliidae
Oestokerkus
Leanchoilia
Alalcomenaeus
midgut gland
phylogenesis
Opis:
The Leanchoiliidae is well−known from abundant material of Leanchoilia, from the Burgess Shale and Chengjiang Konservat−Lagerstätten. The first Australian member of the group is Oestokerkus megacholix gen. et sp. nov., described from the Emu Bay Shale (Cambrian Series 2, Stage 4), at Buck Quarry, Kangaroo Island, South Australia, and is intermediate in age between the well known leanchoiliid species from the Burgess Shale and Chengjiang. Phylogenetic analysis of “short great appendage” arthropods (Megacheira) in the context of the chelicerate stem group resolves the Australian species as sister to Burgess Shale, Utah, and Chengjiang Leanchoilia species, but most readily distinguished from Leanchoilia and Alalcomenaeus by a different telson shape, interpreted as being forked, widening distally, and with a few dorsally curved spines at the posterior angle. Leanchoiliid interrelationships are stable to alternative character weights, and Megacheira corresponds to a clade in most analyses.
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New finds of Rusophycus from the lower Cambrian Ociesęki Sandstone Formation (Holy Cross Mountains, Poland)
Autorzy:
Stachacz, M.
Powiązania:
https://bibliotekanauki.pl/articles/2058996.pdf
Data publikacji:
2012
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Holy Cross Mountains
Lower Cambrian
trace fossils
Rusophycus
Opis:
The Ociesęki Sandstone Formation represents the Holmia-Schmidtiellus and the Protolenus-Issafeniella zones. Seven ichnospecies of Rusophycus, including Rusophycus exsilius isp. nov, are recognized in this formation. Moreover, Rusophycus ispp. A, B, C are recognized. The diagnoses for R. dispar, R. crebrus and R. magnus have been emended and the stratigraphic range of R. versans has been extended. The presence of Rusophycus dispar may suggest a palaeozoogeographical connection between the Małopolska Block, the Baltica palaeocontinent and the Laurentia palaeocontinent.
Źródło:
Geological Quarterly; 2012, 56, 2; 237-248
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The earliest annelids: Lower Cambrian polychaetes from the Sirius Passet Lagerstatte, Peary Land, North Greenland
Autorzy:
Morris, S C
Peel, J.S.
Powiązania:
https://bibliotekanauki.pl/articles/21486.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Polychaeta
Annelida
systematics
annelid
Greenland
polychaete annelid
paleontology
metazoan evolution
Sirius Passet Lagerstatte
Phagmochaeta canicularis
Lower Cambrian
Cambrian
Opis:
Apart from the Phyllopod Bed of the Burgess Shale (Middle Cambrian) polychaete annelids are practically unknown from any of the Cambrian Lagerstätten. This is surprising both because their diversity in the Burgess Shale is considerable, while to date the Chengjiang Lagerstätte which is equally impressive in terms of faunal diversity has no reliable records of any annelids. Here we describe, on the basis of about 40 specimens, Phragmochaeta canicularis gen. et sp. nov. from the Lower Cambrian Sirius Passet Lagerstätte of Peary Land, North Greenland. This makes it by far the oldest known polychaete, with a likely age of lower to middle Atdabanian, The body consists of approximately 20 segments, each bearing notochaetae and neurochaetae. The former appeared to have formed a felt−like covering on the dorsum, whilst the neurochaetae projected obliquely to the longitudinal axis. Apart from minor differences in chaetal size at either end there is no other tagmosis. Details of the head are obscure, and presence of palps, tentacles and eyes are conjectural. Jaws appear to have been absent. The gut was straight, and flanked by massive longitudinal musculature. P. canicularis was evidently benthic, propelling itself on the neurochaetae, with the dorsal neurochaetae conferring protection. Its stratigraphic position and generalized appearance are consistent with P. canicularis being primitive, but the phylogenetic relationships within the polychaetes remain problematic, principally because of paucity of relevant morphological information.
Źródło:
Acta Palaeontologica Polonica; 2008, 53, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 39

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