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Tytuł:
Silurian retiolitid graptolites: Morphology and evolution
Autorzy:
Bates, D E B
Kozlowska, A.
Lenz, A.C.
Powiązania:
https://bibliotekanauki.pl/articles/22802.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Developmental mode and proximal structures are commonly accepted as the best for the recognition of high−level taxonomic categories within the Graptoloidea. The petalolithids and retiolitids are unique in possessing a virgellar ancora and in the latter, distal ancora development. The ancora structures are considered homologous, and the ancorate petalolithids are considered to be the direct ancestors to the retiolitids. The Retiolitidae are unique among the diplograptoids in possessing (1) outer, lateral, ancora sleeve walls (derived from distal extension of the ancora), and (2) a skeletal framework of bandaged lists between which are a succession of very thin and rarely preserved fusellar layers. Retiolitids possess different kinds of thecal profiles and two types of micro−ornamentation on the lists, and these have served to distinguish between the subfamilies Retiolitinae and Plectograptinae. Complete retiolitid morphological terminology is clarified and explained. Cladistic analysis of the retiolitids provides some measure of a better understanding of retiolitid evolution, but adds only modest support for the retention of the two subfamily categories.
Źródło:
Acta Palaeontologica Polonica; 2005, 50, 4; 705-720
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Systematic review of Neocaviafrom the Neogene of Argentina: Phylogenetic and evolutionary implications
Autorzy:
Madozzo-Jaen, M.C.
Perez, M.E.
Montalvo, C.
Tomassini, R.L.
Powiązania:
https://bibliotekanauki.pl/articles/21378.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Caviidae is one of the groups of rodents with the greatest ecomorphological disparity, and with currently three known lineages: Caviinae (cuises), Dolichotinae (maras), and Hydrochoerinae (capybaras). Caviinae include small caviids represented by three extant genera (Microcavia, Cavia, and Galea) and three fossils forms (Dolicavia, Palaeocavia, and Neocavia). In Argentina, the fossil record of Caviinae is continuous and abundant since the late Miocene. Neocavia, specifically, is represented by different species recorded in the late Miocene–Pliocene. Here, we describe a new species of Neocavia from the late Miocene–early Pliocene of the Cerro Azul Formation (La Pampa Province, Argentina), and provide a re-description of already known species (Neocavia lozanoi and “Neocavia depressidens”). Also, we perform a more comprehensive review of the genus and include the Neocavia species in a phylogenetic context within Caviinae. We analyze the main patterns of the evolution of the tympanic bullae within Caviidae, and infer about a possible occasional fossorial habit of Neocavia. The morphological and phylogenetic analyses indicate that Neocavia is more closely related to Dolicavia and Microcavia than to the other Caviinae, and confirm the monophyly of the genus, with at least two clearly differentiable species. Since this study cannot confirm the systematic position and validity of “N. depressidens”, we suggest not to use this taxon as a biostratigraphic indicator.
Źródło:
Acta Palaeontologica Polonica; 2018, 63, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ecomorphology and bone microstructure of Proterochampsia from the Chanares Formation
Autorzy:
Arcucci, A.
Previtera, E.
Mancuso, A.C.
Powiązania:
https://bibliotekanauki.pl/articles/21349.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Proterochampsians are a South American endemic group of non-archosaurian archosauriforms with morphological characteristics recollecting Recent crocodilians, and therefore have been proposed as aquatic species. However, this has not been based on careful examination of anatomical and histological features. We provide a review of the morphological and histological evidence present in the skeleton of proterochampsids and discuss its implications for inferring the lifestyles of these organisms. Anatomical features such as a secondary palate, marginal dentition, palatine teeth, morphology of the tail, limb modification, and dermal armor are reviewed, and details of histological structures are described based on bone thin sections. Histological examination reveals a predominance of fibrolamellar bone tissue, suggesting rapid periosteal osteogenesis and therefore overall fast bone growth. The existence of discontinuities (LAGs) demonstrates that these animals responded to changes in their environment. Ecomorphological features do not provide definitive evidence for the lifestyles of proterochampsids, but allow us to propose a terrestrial/amphibious condition. The same is true of the histological features, particularly compactness of the bone.
Źródło:
Acta Palaeontologica Polonica; 2019, 64, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new capybara from the late Miocene of San Juan Province, Argentina, and its phylogenetic implications
Autorzy:
Cerdeno, E.
Perez, M.E.
Deschamps, C.M.
Contreras, V.H.
Powiązania:
https://bibliotekanauki.pl/articles/20827.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
A new hydrochoerine rodent, Cardiatherium calingastaense sp. nov. (Caviidae), is described based on the specimen INGEO-PV 87. It was recovered from the late Miocene Las Flores Formation, cropping out at the Puchuzum locality, San Juan Province, Argentina. The new species is based on a particular combination of characters, among which the following can be highlighted: p4 with internal fissures equally deep as in Cardiatherium paranense, secondary external fissure as in Cardiatherium patagonicum, and lacking the fifth internal fissure and supernumerary internal fissure, as in C. paranense; m3 with a conspicuous labial column in the posterior ramus of the second prism; very deep primary and secondary external fissures in upper cheek teeth, the former producing a labial strong step-shaped profile in M2; sagittal crest on the parietals; bullae small in ventral view; scars of the origin of the masseter medialis muscle with an anterior projection up to the level of the incisive foramen and the maxilla-premaxilla suture. The phylogenetic analysis supports the taxonomic proposal of creating a new species of Cardiatherium and shows C. calingastaense sp. nov. as the sister group of the other species of the genus. The lineage leading to the clade Cardiatherium + largest capybaras would have originated at least during the Chasicoan SALMA (early late Miocene). Cardiatherium calingastaense sp. nov. adds to the previous record of Cardiatherium chasicoense and Cardiatherium paranense in the late Miocene of San Juan and Mendoza provinces, respectively, thus increasing the diversity of capybaras in central-west Argentina.
Źródło:
Acta Palaeontologica Polonica; 2019, 64, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Late Miocene capybaras from Argentina: Skull anatomy, taxonomy, evolution, and biochronology
Autorzy:
Vucetich, M.G.
Deschamps, C.M.
Vieytes, E.C.
Montalvo, C.I.
Powiązania:
https://bibliotekanauki.pl/articles/945889.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
Miocene
Late Miocene
capybara
mammalia
Rodentia
Cavioidea
Hydrochoerinae
Argentina
skull
anatomy
taxonomy
evolution
biochronology
morphometry
biostratigraphy
Opis:
Fossil capybaras are morphologically extremely varied, but previous studies have disagreed on whether this diversity reflects intraspecific variation or the existence of multiple species. Here, we review the capybaras from the classic Argentinian Late Miocene localities of Paraná River cliffs (“conglomerado osífero” of the Ituzaingó Formation, Entre Ríos), and Chillhué and Guatraché shallow lakes (Cerro Azul Formation, La Pampa), and perform a morphometric analysis of their upper cheek teeth and the posterior portion of the rostrum. Our results confirm that all of the specimens from the “conglomerado osífero” belong to the single species Cardiatherium paranense. In addition, we refer a specimen from Tupungato (Río de los Pozos Formation, Mendoza) to C. paranense, thus expanding its geographical range. The material from La Pampa represents a different taxon, and is here preliminary referred to Cardiatherium aff. orientalis. Our systematic interpretation of Late Miocene capybaras suggests that the early radiation of this group was not as explosive as previously thought, and was likely constrained by the early acquisition of large size, increasing complexity of the cheek teeth, and probably semi-aquatic habits.
Źródło:
Acta Palaeontologica Polonica; 2014, 59, 3; 517-535
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rostral reconstruction of South American hippidiform equids: New anatomical and ecomorphological inferences
Autorzy:
Bernardes, C.
Sicuro, F.L.
Avilla, L.S.
Pinheiro, A.E.P.
Powiązania:
https://bibliotekanauki.pl/articles/22292.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
The Pleistocene Equus (Amerhippus) and hippidiforms frequently occur together in the South American fossil record, suggesting a possible case of sympatry and syntopy. Although resembling each other in their overall morphology, their rostra show distinct differences. While Equus (Amerhippus) resembles extant horses, hippidiforms are characterised by slender nasal bones, a retracted nasal notch at the level of M2–M3 or posterior to M3, and the presence of dorsal preorbital fossae of variable depth. Here we present an anatomical reconstruction of the muzzle of hippidiforms based on homologous patterns in the extant horse Equus caballus, together with a morphofunctional analysis of their rostra and a comparative analysis of premaxillary shape. The rostral morphology of hippidiforms suggests the presence of a developed upper lip with prehensile function, as occurs in extant black rhinoceros. This prehensile structure could be ecomorphologically related to browsing, thus reducing niche overlap with Equus(Amerhippus), and hence competitive pressure.
Źródło:
Acta Palaeontologica Polonica; 2013, 58, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bashkirian rugose corals from the Carboniferous Mattson Formation in the Liard Basin, northwest Canada - stratigraphic and paleobiogeographic implications
Autorzy:
Fedorowski, J.
Bamber, E.W.
Richards, B.C.
Powiązania:
https://bibliotekanauki.pl/articles/20117.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Colonies of the rugose corals Nemistium liardense sp. nov. and Heritschioides simplex sp. nov. were collected from limestone in the upper member of the Mattson Formation in the Liard Range in the Northwest Territories and are the only known identifiable coral species from the Mattson Fm. The Mattson Fm., deposited in the Liard Basin west of the syndepositional Bovie reverse fault, comprises sandstone with subordinate shale and carbonates deposited during several delta cycles. The close morphological similarity and identical mode of offsetting in N. liardense colonies from the Mattson Fm. and the allochthonous Stikine Terrane of British Columbia indicate they belong in the same species. This and the morphological similarity between H. simplex and the late Serpukhovian to early Bashkirian H. columbicum allow assignment of the coral-bearing part of the upper Mattson Fm. to Bashkirian Foraminiferal Biozone 20. Widespread occurrence of the genus Nemistium confirms open communication between the Liard Basin region and the western European and northern African seas.
Źródło:
Acta Palaeontologica Polonica; 2019, 64, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A taxonomic and biogeographic review of the fossil tapirs from Bolivia
Autorzy:
Ferrero, B.S.
Soibelzon, E.
Holanda, E.C.
Gasparini, G.M.
Zurita, A.E.
Mino-Boilini, A.R.
Powiązania:
https://bibliotekanauki.pl/articles/945888.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
taxonomy
biogeography
fossil
tapir
Tapirus tarijensis
Bolivia
Quaternary
South America
paleontology
mammalia
Perissodactyla
Tapiridae
mammal
Opis:
Fossil remains of South American tapirs are often fragmentary and scarce compared with those of other mammals that entered South America during the “Great American Biotic Interchange”. Here, we review and add to the Pleistocene tapir remains from the Tarija Valley (Bolivia), and provide a taxonomic re-evaluation of Tapirus tarijensis. T. tarijensis was a large-sized animal, approximating the size of the living Malaysian T. indicus and the extinct North American T. haysii. The geographical distribution of Pleistocene records of Tapirus in South America indicates that T. tarijensis was the only known species inhabiting the Tarija Valley during this time.
Źródło:
Acta Palaeontologica Polonica; 2014, 59, 3; 505-516
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The phanerozoic diversity of agglutinated foraminifera: Origination and extinction rates
Autorzy:
Kaminski, M A
Setoyama, E.
Cetean, C.G.
Powiązania:
https://bibliotekanauki.pl/articles/22888.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
phanerozoic diversity
Foraminifera
origination
extinction rate
biodiversity
fossil
paleontology
Opis:
New diversity curves for agglutinated foraminiferal genera are presented based on the stratigraphic ranges of 764 genera distributed over the 91 Phanerozoic chronostratigraphic subdivisions given in the ICS timescale. The data set for this analysis is based on the stratigraphic ranges of agglutinated genera published in Foraminiferal Genera and their Classification, 218 of which have been modified based upon subsequently published studies and new observations. Additionally, a total of 136 genera have been newly described or reinstated subsequent to the publication of Foraminiferal Genera and their Classification. The revision of stratigraphic ranges is part of the effort by the Grzybowski Foundation’s International Working Group on Foraminiferal Classification to compile a new Catalogue of Agglutinated Foraminiferal Genera. The mean standing diversity of agglutinated foraminiferal genera was compiled by counting the number of boundary crossers rather than the number of genera in each stage. This diversity curve displays a general upward trend throughout the Phanerozoic, punctuated by peaks and troughs of variable magnitude. The curve shows a period of initial radiation from the Early Cambrian to the Early Silurian, followed by a plateau to the Late Permian. The Permian/Triassic and the Triassic/Jurassic boundaries are characterised by small dips in the diversity record. The Jurassic begins with an exponential rise in mean standing diversity that continues to the Cenomanian. The Cenomanian to Holocene record of mean standing diversity is characterised by four peaks and troughs that are roughly in line with the cycles of global climate, with reductions in diversity in the end−Cenomanian, end−Cretaceous, and end−Miocene. Excluding modern values, the Phanerozoic maximum in the number of genera with a fossil record is observed in the Cenomanian, whereas the maximum Phanerozoic mean standing diversity is observed in the Langhian stage of the Miocene. The highest per−capita origination rates are observed in the Hettangian, Dapingian, Pleistocene, and Sheinwoodian (mid−Silurian). Linear regression analysis of the origination rates reveals a decrease towards the Holocene, in agreement with findings of Raup and Sepkoski. The highest per−capita extinction rates are observed in the Messinian, late Silurian (Gorstian), Hirnantian (latest Ordovician), and Maastrichtian. The background extinction rate shows an increasing trend towards the Recent, which is in disagreement with the findings of Raup and Sepkoski. We attribute this apparent discrepancy to the Late Cretaceous to Palaeogene extinctions of shallower−water larger agglutinates and the pull of the end−Miocene extinction event.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 3; 529-539
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biotic interaction between spionid polychaetes and bouchardiid brachiopods: Paleoecological, taphonomic and evolutionary implications
Autorzy:
Rodrigues, S.C.
Simoes, M.G.
Kowalewski, M.
Petti, M.A.V.
Nonato, E.F.
Martinez, S.
del Rio, C.J.
Powiązania:
https://bibliotekanauki.pl/articles/21792.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
biotic interaction
spionid polychaete
polychaete
bouchardiid brachiopod
brachiopod
paleoecology
evolution
Brachiopoda
Spionidae
Caulostrepsis
Bouchardia
Cenozoic
Brazil
Opis:
Shells of Bouchardia rosea (Brachiopoda, Rhynchonelliformea) are abundant in Late Holocene death assemblages of the Ubatuba Bight, Brazil, SW Atlantic. This genus is also known from multiple localities in the Cenozoic fossil record of South America. A total of 1211 valves of B. rosea, 2086 shells of sympatric bivalve mollusks (14 nearshore localities ranging in depth from 0 to 30 m), 80 shells of Bouchardia zitteli, San Julián Formation, Paleogene, Argentina, and 135 shells of Bouchardia transplatina, Camacho Formation, Neogene, Uruguay were examined for bioerosion traces. All examined bouchardiid shells represent shallow−water, subtropical marine settings. Out of 1211 brachiopod shells of B. rosea, 1201 represent dead individuals. A total of 149 dead specimens displayed polychaete traces (Caulostrepsis). Live polychaetes were found inside Caulostrepsis borings in 10 life−collected brachiopods, indicating a syn−vivo interaction (Caulostrepsis traces in dead shells of B. rosea were always empty). The long and coiled peristomial palps, large chaetae on both sides of the 5th segment, and flanged pygidium found in the polychaetes are characteristic of the polychaete genus Polydora (Spionidae). The fact that 100% of the Caulostrepsis found in living brachiopods were still inhabited by the trace−making spionids, whereas none was found in dead hosts, implies active biotic interaction between the two living organisms rather than colonization of dead brachiopod shells. The absence of blisters, the lack of valve/site stereotypy, and the fact that tubes open only externally are all suggestive of a commensal relationship. These data document a new host group (bouchardiid rhynchonelliform brachiopods) with which spionids can interact (interestingly, spionid−infested sympatric bivalves have not been found in the study area despite extensive sampling). The syn−vivo interaction indicates that substantial bioerosion may occur when the host is alive. Thus, the presence of such bioerosion traces on fossil shells need not imply a prolonged post−mortem exposure of shells on the sea floor. Also, none of the Paleogene and Neogene Bouchardia species included any ichnological evidence for spionid infestation. This indicates that the Spionidae/ Bouchardia association may be geologically young, although the lack of older records may also reflect limited sampling and/or taphonomic biases.
Źródło:
Acta Palaeontologica Polonica; 2008, 53, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New lizards and rhynchocephalians from the Lower Cretaceous of Southern Italy
Autorzy:
Evans, S E
Raia, P.
Barbera, C.
Powiązania:
https://bibliotekanauki.pl/articles/20920.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
predation
Italy
Cretaceous
Rhynchocephalia
Squamata
new lizard
Lepidosauria
lizard
paleobiogeography
paleontology
Opis:
The Lower Cretaceous (Albian age) locality of Pietraroia, near Benevento in southern Italy, has yielded a diverse assemblage of fossil vertebrates, including at least one genus of rhynchocephalian (Derasmosaurus) and two named lizards (Costasaurus and Chometokadmon), as well as the exquisitely preserved small dinosaur, Scipionyx. Here we describe material pertaining to a new species of the fossil lizard genus Eichstaettisaurus (E. gouldi sp. nov.). Eichstaettisaurus was first recorded from the Upper Jurassic (Tithonian age) Solnhofen Limestones of Germany, and more recently from the basal Cretaceous (Berriasian) of Montsec, Spain. The new Italian specimen provides a significant extension to the temporal range of Eichstaettisaurus while supporting the hypothesis that the Pietraroia assemblage may represent a relictual island fauna. The postcranial morphology of the new eichstaettisaur suggests it was predominantly ground−living. Further skull material of E. gouldi sp. nov. was identified within the abdominal cavity of a second new lepidosaurian skeleton from the same locality. This second partial skeleton is almost certainly rhynchocephalian, based primarily on foot and pelvic structure, but it is not Derasmosaurus and cannot be accommodated within any known genus due to the unusual morphology of the tail vertebrae.
Źródło:
Acta Palaeontologica Polonica; 2004, 49, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new plesiosaur from the Lower Jurassic of Portugal and the early radiation of Plesiosauroidea
Autorzy:
Puertolas-Pascual, E.
Marx, M.
Mateus, O.
Saleiro, O.
Fernandes, A.E.
Marinheiro, J.O.
Tomas, C.
Mateus, S.
Powiązania:
https://bibliotekanauki.pl/articles/2082325.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Plesiosauria
radiation
Sinemurian
Jurassic
Iberian Peninsula
Europe
Opis:
A new plesiosaur partial skeleton, comprising most of the trunk and including axial, limb, and girdle bones, was collected in the lower Sinemurian (Coimbra Formation) of Praia da Concha, near São Pedro de Moel in central west Portugal. The specimen represents a new genus and species, Plesiopharos moelensis gen. et sp. nov. Phylogenetic analysis places this taxon at the base of Plesiosauroidea. Its position is based on this exclusive combination of characters: presence of a straight preaxial margin of the radius; transverse processes of mid-dorsal vertebrae horizontally oriented; ilium with sub-circular cross section of the shaft and subequal anteroposterior expansion of the dorsal blade; straight proximal end of the humerus; and ventral surface of the humerus with an anteroposteriorly long shallow groove between the epipodial facets. In addition, the new taxon has the following autapomorphies: iliac blade with less expanded, rounded and convex anterior flank; highly developed ischial facet of the ilium; apex of the neural spine of the first pectoral vertebra inclined posterodorsally with a small rounded tip. This taxon represents the most complete and the oldest plesiosaur species in the Iberian Peninsula. It is also the most complete, best preserved, and oldest marine vertebrate in the region and testifies to the incursion of marine reptiles in the newly formed proto-Atlantic sea, prior to the Atlantic Ocean floor spreading in the Early Cretaceous.
Źródło:
Acta Palaeontologica Polonica; 2021, 66, 2; 369-388
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Late Cambrian acritarch Lusatia: Taxonomy, palaeogeography, and biostratigraphic implications
Autorzy:
Albani, R.
Bagnoli, G.
Ribecai, C.
Raevskaya, E.
Powiązania:
https://bibliotekanauki.pl/articles/21158.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Acritarcha
Cambrian
Furongian
Late Cambrian
Lusatia
acritarch
biostratigraphy
marine phytoplankton
paleogeography
paleontology
taxonomy
phytoplankton
systematics
distribution
Opis:
Intraspecific variability of the herein emended diacrodian acritarch Lusatia dendroidea is described based on late Cambrian (Furongian) well preserved material from Spain, the High Arctic of Russia, and the East−European Platform. L. dendroidea, displays bipolar asymmetric morphology and, as originally defined, consists of three long major processes originating from the “corners” of its vesicle. Specimens with one, two and four major processes are considered to represent morphological variations of the most common three process form. Based on its narrow stratigraphic range, widespread palaeogeographic distribution, and distinctive morphology, L. dendroidea is an excellent guide fossil for the Furongian.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Brachiopods from the uppermost Lower Ordovician of Peru and their palaeogeographical significance
Autorzy:
Gutierrez-Marco, J C
Villas, E.
Powiązania:
https://bibliotekanauki.pl/articles/22645.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
systematics
Peru
Celtic Province
Lower Ordovician
brachiopod
Ordovician
geological setting
paleogeography
Ahtiella
geographic setting
Brachiopoda
paleontology
Opis:
The studied brachiopod assemblages from the uppermost Lower Ordovician beds of Peru are of very low diversity and are among the northernmost known strata of that age in South America. They have been collected at the Carcel Puncco canyon of the Inambari River, near San Gabán in the easternmost Eastern Cordillera. Of the six species described, Euorthisina orthiformis and Paralenorthis immitatrix were already known from the Bolivian outcrops of the same Andean Eastern Cordillera; two species are new: Ahtiella zarelae Villas sp. nov. and Paralenorthis carlottoi Villas sp. nov. The new species of Ahtiella, of late Floian age, represent the oldest record of the genus characteristic of Celtic assemblages. During the early Mid Ordovician the genus migrated eastward from this region into the north margin of proto−Avalonia and after that, in Llanvirn times, into Baltica. During the early Llanvirn Ahtiella also migrated westward reaching the Precordillera Argentina region. Brachiopod faunal affinities suggest that there was a closer proximity of Avalonia with the Central Andean Basin, in similar temperate latitudes, than with the Southwestern European Platform, placed in very high latitude. Paralenorthis does not give any palaeogeographical signal, since it is known from all latitudes and palaeocontinents. Nevertheless, the occurrence of Euorthisina reinforces the Gondwanan signature of the region, since this genus spread during the Arenig throughout the middle latitude belt at the Gondwana margins, although it also colonised sub−polar latitudes, coinciding with the Llanvirn transgression over North Gondwana.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ostracods and facies of the Early and Middle Frasnian at Devils Gate in Nevada: Relationship to the Alamo Event
Autorzy:
Casier, J -G
Berra, I.
Olempska, E.
Sandberg, C.
Preat, A.
Powiązania:
https://bibliotekanauki.pl/articles/23394.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
ostracod
Early Frasnian
Frasnian
Middle Frasnian
Nevada
relationship
Alamo Event
Ostracoda
conodont
sedimentology
paleoecology
Opis:
In order to document the Alamo Event and to investigate its influence on shallow−marine environments, we undertook a study of ostracods, conodonts, and analysis of the sedimentology of the lower member of the type Devils Gate Limestone. Six major carbonate microfacies (MF1–MF6) ranging from open−marine environments below storm wave base to pre−evaporitic supratidal lagoons were recognized. The sedimentological study detected no important sedimentological changes during the Alamo Event; only an influx of detrital material and lithoclasts indicate that an unusual event had occurred. Ostracods are generally rare or absent in the lower member of the Devils Gate Limestone, and only 2,000 carapaces, valves and fragments were extracted; from these some 26 taxa were identified. Two new species, Voronina? eureka and Serenida dorsoplicata are proposed. The ostracods belong to the Eifelian Mega−Assemblage and their distribution was influenced by strong salinity variations. Because of the rarity and low diversity of ostracods and conodonts in samples collected from the lower part of the lower member of the Devils Gate Limestone it is not adequate to demonstrate conclusively an extinction event close to the Alamo Event Bed. Nevertheless the greater abundance and diversity of ostracods above this bed seems to indicate that the Alamo Event did not result in significant extinction of ostracod taxa in this shallow water setting. The ostracod fauna present in the lower member of the Devils Gate Limestone suggests faunal exchanges between Nevada and the Russian Platform via the Western Canadian platform.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 4; 813-828
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
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