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Wyszukujesz frazę "Holmer, L. E." wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
Lingulate brachiopods from Lower Ordovician [Tremadoc] chalcedonites, Holy Cross Mountains, Poland
Autorzy:
Holmer, L E
Biernat, G.
Powiązania:
https://bibliotekanauki.pl/articles/19951.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Lingulata
paleobiology
Lower Ordovician
Polska
brachiopod
Ordovician
Holy Cross Mountains
Brachiopoda
Opis:
Lingulate brachiopods from chalcedonites of Tremadoc age are redescribed based on new material from the Holy Cross Mountains, Poland. The fauna includes 18 species, of which Elliptoglossa polonica and Siphonotretella popovi are new. The enigmatic Orbiculoidea? subovalis Biernat is redescribed as a species of the recently erected aberrant paterulids Diencobolus Holmer, Popov, Koneva, and Bassett. The fauna includes also Acrotreta dissimilis (Biernat), ?Ditreta dividua Biernat, Semitreta maior Biernat, Eurytreta minor Biernat, Mamatia retracta (Popov), Orbithele ceratopygarum (Brøgger), Siphonobolus uralensis (Lermontova), Alichovia analogica Biernat, Pomeraniotreta sp., Akmolina sp., Rowellella sp., Acanthambonia sp. A, Acanthambonia? sp. B, Leptembolon cf. lingulaeformis (Mickwitz), and the earliest known species of Eoconulus. Most of the recorded lingulate species are endemic, but a significant number are now known also from eastern Kazakhstan and the South Urals, as well as from the Tremadoc of Sweden and Norway.
Źródło:
Acta Palaeontologica Polonica; 2002, 47, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Early Cambrian [Botomian] stem group brachiopod Mickwitzia from Northeast Greenland
Autorzy:
Skovsted, C B
Holmer, L.E.
Powiązania:
https://bibliotekanauki.pl/articles/22580.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
ontogenesis
brachiopod
shell structure
Greenland
Cambrian
Mickwitzia
Brachiopoda
paleontology
Botomian
Opis:
The problematic brachiopod Mickwitzia Schmidt, 1888 is re−described based on new material of M. cf. occidens Walcott, 1908 from the Early Cambrian (Botomian) Bastion and Ella Island formations of Northeast Greenland. Etched material demonstrates that Mickwitzia has a lingulid−like juvenile (“larval”) shell with trails of nick−points, reflecting the movement of marginal setae. Juvenile and early mature ventral valves have a lingulid−like pseudointerarea with a pedicle groove. The shell of M. cf. occidens is only partially phosphatic, in particular around the juvenile–early mature shell in both valves. The phosphatic shell includes at least two types of cylindrical structures: (1) slender columns identical with the columns of acrotretoid brachiopods and (2) relatively thicker tubes which may be open to the exterior surface and have internal striations (on the ventral pseudointerarea). The striations are most likely imprints of microvilli and these tubes can be inferred to have contained setae. The thinner linguliform columns and thicker setigerous striated tubes are considered to be homologous with identical structures in the sellate and mitral sclerites of the problematic Micrina, which has been identified as a probable primitive stem group of the Brachiopoda. Mickwitzia represents a more derived member of the stem group Brachiopoda.
Źródło:
Acta Palaeontologica Polonica; 2003, 48, 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-part preservation in a linguliform brachiopod from the lower Cambrian Wulongqing Formation [Guanshan fauna] of Yunnan, South China
Autorzy:
Hu, S
Zhang, Z.
Holmer, L.E.
Skovsted, C.B.
Powiązania:
https://bibliotekanauki.pl/articles/20740.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
preservation
linguliform brachiopo
Lower Cambrian
Cambrian
Wulongqing Formation
Yunnan Province
South China
brachiopod
Linguliformea
benthic community
China
Opis:
Linguliform brachiopods were important components of early Cambrian benthic communities. However, exceptionally preserved soft parts in Cambrian linguliform brachiopods are extremely sparse, and the most important findings are from the early Cambrian Chengjiang Konservat Lagerstätte of Kunming, southern China. Here we describe the first record of preserved soft−part anatomy in a linguliform brachiopod from the early Cambrian Guanshan fauna (Wulongqing Formation, Palaeolenus Zone); a unit which is considerably younger than the Chengjiang fauna. The well preserved soft anatomy include linguliform pedicles, marginal setae and, in a few cases, an intact lophophore imprint. The pedicle has pronounced surface annulations, with its proximal−most part enclosing the apex of the ventral pseudointerarea; the pedicle is up to 51 mm long, corresponding to more than 4 times the sagittal length of the shell, and 12% of the maximum valve width. In details of their preservation, these new fossils exhibit striking similarities with the linguliforms from the older Chengjiang fauna, and all specimens are preserved in a compressed state as flattened impressions. The new linguliform has an elongate oval to subtriangular shell and an elongate triangular ventral pseudointerarea; the pedicle emerged from an apical foramen through a poorly preserved internal pedicle tube. The new linguliform is most similar to the mostly organic−shelled siphonotretoid−like brachiopod Acanthotretella spinosa, recently described from the classic middle Cambrian Burgess Shale Konservat Lagerstätte, British Columbia, Canada. The new species Acanthotretella decaius sp. nov. is described; it differs from A. spinosa in having a slightly thicker pedicle, and a larger and more rigid, probably partly mineralised shell, indicating that the mostly organic shell of A. spinosa may represent a secondary reduction of shell mineralisation. However, the spine−like setae of the new species are unfortunately poorly preserved only at the margin of the shell, but the new species is referred tentatively to the Superfamily Siphonotretoidea. The occurrence of A. decaius in the Guanshan fauna is the first lower Cambrian (Series 2, early Stage 4) record of both Acanthotretella and siphonotretoids, and it represents the first description of a lophophore and digestive tract from the siphonotretoid lineage.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 3; 495-505
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
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
    Wyświetlanie 1-5 z 5

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