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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:
Cranial anatomy and phylogenetic position of the titanosaurian sauropod Bonitasaura salgadoi
Autorzy:
Gallina, P.
Apesteguia, S.
Powiązania:
https://bibliotekanauki.pl/articles/20275.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
Sauropoda
Titanosauria
skull
Late Cretaceous
Río Negro
Argentina
Cretaceous
cranial anatomy
phylogenetic position
titanosaurian sauropod
sauropod
Bonitasaura salgadoi
skeleton
bone
cranial bone
Opis:
Knowledge of titanosaurian cranial anatomy has improved substantially in the last decade because several skulls have come to light or were restudied. The discovery of Bonitasaura salgadoi, a partial titanosaurian skeleton including cranial bones, permitted the definitive recognition of square jaws in a titanosaurian sauropod as well as a peculiar skull morphology that increases the morphological diversity of the group. Here we present a full description and illustration of the skull material of B. salgadoi. Among cranial bones, the lacrimal, quadrate, and dentary exhibit apomorphic differences from those of other titanosaurians. Conversely, the frontal and parietal are more conservative. A phylogenetic analysis recovers B. salgadoi as a member of the Titanosauria, related to mid−sized to large titanosauroids from the Turonian–Campanian of South America, in contrast to a previous hypothesis that suggested a nemegtosaurid affinity. The skull reconstruction presented here shows that the skull of B. salgadoi is anteroposteriorly short and dorsoventrally high, contrasting with the elongate skull of Rapetosaurus krausei.
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chaetopterid tubes from vent and seep sites: Implications for fossil record and evolutionary history of vent and seep annelids
Autorzy:
Kiel, S
Dando, P.R.
Powiązania:
https://bibliotekanauki.pl/articles/23540.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
chaetopterid tube
vent
seep site
fossil record
evolution
history
annelid
fauna
paleontology
Vestimentifera
Pogonophora
Siboglinidae
Chaetopteridae
tubeworm
chemosynthetic ecosystem
hot vent
cold seep
Opis:
Vestimentiferan tube worms living at deep−sea hydrothermal vents and cold seeps have been considered as a clade with a long and continuing evolutionary history in these ecosystems. Whereas the fossil record appears to support this view, molecular age estimates do not. The two main features that are used to identify vestimentiferan tubes in the fossil record are longitudinal ridges on the tube’s surface and a tube wall constructed of multiple layers. It is shown here that chaetopterid tubes from modern vents and seeps—as well as a number of fossil tubes from shallow−water environments—also show these two features. This calls for a more cautious interpretation of tubular fossils from ancient vent and seep deposits. We suggest that: current estimates for a relatively young evolutionary age based on molecular clock methods may be more reliable than the inferences of ancient “vestimentiferans” based on putative fossils of these worms; not all of these putative fossils actually belong to this group; and that tubes from fossil seeps should be investigated for chitinous remains to substantiate claims of their potential siboglinid affinities.
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 3; 443-448
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Basal abelisaurid and carcharodontosaurid theropods from the Lower Cretaceous Elrhaz Formation of Niger
Autorzy:
Sereno, P C
Brusatte, S.L.
Powiązania:
https://bibliotekanauki.pl/articles/21335.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Allosauroidea
Cretaceous
Elrhaz Formation
paleontology
Eocarcharia
Africa
Lower Cretaceous
Theropoda
Kryptops
carcharodontosaurid theropod
Abelisauridae
theropod
Carcharodontosauridae
abelisaurid theropod
Niger
Opis:
We report the discovery of basal abelisaurid and carcharodontosaurid theropods from the mid Cretaceous (Aptian–Albian, ca. 112 Ma) Elrhaz Formation of the Niger Republic. The abelisaurid, Kryptops palaios gen. et sp. nov., is represented by a single individual preserving the maxilla, pelvic girdle, vertebrae and ribs. Several features, including a maxilla textured externally by impressed vascular grooves and a narrow antorbital fossa, clearly place Kryptops palaios within Abelisauridae as its oldest known member. The carcharodontosaurid, Eocarcharia dinops gen. et sp. nov., is represented by several cranial bones and isolated teeth. Phylogenetic analysis places it as a basal carcharodontosaurid, similar to Acrocanthosaurus and less derived than Carcharodontosaurus and Giganotosaurus. The discovery of these taxa suggests that large body size and many of the derived cranial features of abelisaurids and carcharodontosaurids had already evolved by the mid Cretaceous. The presence of a close relative of the North American genus Acrocanthosaurus on Africa suggests that carcharodontosaurids had already achieved a trans−Tethyan distribution by the mid Cretaceous.
Źródło:
Acta Palaeontologica Polonica; 2008, 53, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wear facets and enamel spalling in tyrannosaurid dinosaurs
Autorzy:
Schubert, B W
Ungar, P.S.
Powiązania:
https://bibliotekanauki.pl/articles/20396.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
diet
Tyrannosauridae
lateral tooth
dinosaur
Gorgosaurus
enamel spalling
paleontology
Daspletosaurus
Opis:
Numerous paleontologists have noted wear facets on tyrannosaurid lateral teeth over the past century. While several workers have proposed explanations for these features, there remains to this day no consensus concerning their etiology. Here we report on an examination of wear surfaces on these teeth from the Upper Cretaceous (mid−Campanian) Judith River Group of southern Alberta, Canada. This study reveals two distinct types of wear features on the labial and lingual sides of tyrannosaurid lateral teeth: irregular “spalled” surfaces and wear facets. The irregular spalled surfaces typically extend to the apex of the tooth, which evidently reflects flaking of enamel resulting from forces produced during contact between tooth and food. These surfaces are often rounded, presumably from antemortem wear following spalling. Wear striations on these surfaces are oriented heterogeneously. The wear facets, in contrast, occur on only one side of the tooth and are typically elliptical in outline and evince parallel wear striations. Similar patterns of parallel wear striations in extant mammals reflect tooth−tooth contact. We therefore propose that wear facets in tyrannosaurids were formed by repeated tooth−tooth contact between the lingual side of maxillary teeth and labial side of dentary teeth. It remains unclear whether this contact was serendipitous or adaptive, though it appears to be unusual for reptiles, as we have found no evidence for wear facets in extant varanids and crocodilians.
Źródło:
Acta Palaeontologica Polonica; 2005, 50, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Late Cretaceous mammals from the Intertrappean beds of Rangapur, India and paleobiogeographic framework
Autorzy:
Rana, R S
Wilson, G.P.
Powiązania:
https://bibliotekanauki.pl/articles/21414.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Eutheria
mammal
Gondwana
Cretaceous
Late Cretaceous
tooth
Intertrappean bed
biogeography
India
Rangapur
paleobiogeography
paleontology
Opis:
A new mammal−bearing locality from the Intertrappean beds (Maastricthian) of Rangapur, Andhra Pradesh, India provides isolated teeth referable to Deccanolestes and a new eutherian, Sahnitherium rangapurensis. Dental comparisons with Cimolestes, Procerberus, and Aboletylestes do not support proposed “palaeoryctoid” affinities for Deccanolestes. Although similarities exist with Otlestes and Batodon, Deccanolestes is currently considered to be of uncertain familial affinities. Sahnitherium rangapurensis exhibits similarities to Procerberus, Paranyctoides, Alostera, Aboletylestes, and Avitotherium, but it is here placed within Eutheria incertae sedis. Despite family level taxonomic uncertainties, the new material confirms the presence of eutherians on the Indian subcontinent during the Late Cretaceous. A Eurasian connection via an early collision or some other dispersal route may explain these paleobiogeographic data, but other hypotheses are considered. In particular, paleogeographic, paleontological, and molecular systematic data hint that boreosphenidan mammals may have had wider distribution on Gondwana during the Cretaceous than previously supported.
Źródło:
Acta Palaeontologica Polonica; 2003, 48, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Unsuccessful predation on Middle Paleozoic plankton: Shell injury and anomalies in Devonian dacryoconarid tentaculites
Autorzy:
Berkyova, S
Fryda, J.
Lukes, P.
Powiązania:
https://bibliotekanauki.pl/articles/22057.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Tentaculitoidea
tentaculite
predation
Middle Paleozoic
Paleozoic
plankton
Devonian
shell repair
dacryoconarid tentaculite
paleontology
Opis:
Anomalous development of shell ornamentation and repaired shell injury in the Early Devonian dacryoconarid tentaculites are documented and interpreted as either a repaired injury of the shell (evidence of unsuccessful predation obscured by recrystallization), or as a result of an anomalous function of the mantle, caused by injury of the soft body. The manner of shell repair, which resembles the way that some modern marine animals, such as mollusks, repair their shells, is discussed. The issue of phylogenetic affinities of tentaculites has been also outlined. These findings represent the first documentation of unsuccessful predation on the Middle Paleozoic plankton.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 2
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:
Echinoid burrow Bichordites monastiriensis from the Oligocene of NE Italy
Autorzy:
Bernardi, M
Boschele, S.
Ferretti, P.
Avanzini, M.
Powiązania:
https://bibliotekanauki.pl/articles/22207.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
echinoid burrow
Bichordites monastiriensis
Oligocene
Italy
trace fossil
fossil
paleontology
Bichordites
Upogebia
foredeep
geological setting
Opis:
Several specimens of trace fossil Bichordites monastiriensis were discovered in two shallow water Oligocene sandstone beds from Valsugana (Trentino, NE Italy) representing the oldest documented occurrence for this ichnospecies. They are grazing−crawling (pascichnion−repichnion) structures and are occasionally associated with enlarged structures that can be interpreted as resting traces (cubichnia) and assigned to the ichnogenus Cardioichnus. The resulting Bichordites–Cardioichnus compound trace fossil is here described for the first time. In the basal part of some specimens, skeletal remains of Eupatagus ornatus were found in life position. This founding enables to widen the spectrum of known Bichordites tracemakers. Exceptional conditions of preservation of one specimen extending in two beds recording different environmental conditions gave an opportunity to document the effects of various taphonomical histories on the preservation of this traces.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 3; 479-486
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ecological significance of the arthropod fauna from the Jurassic (Callovian) La Voulte Lagerstatte
Autorzy:
Charbonnier, S.
Vannier, J.
Hantzpergue, P.
Gaillard, Ch.
Powiązania:
https://bibliotekanauki.pl/articles/22428.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
ecological significance
arthropod
fauna
Jurassic
Callovian
Lagerstatte
Arthropoda
Crustacea
Thylacocephala
France
paleontology
Opis:
The La Voulte Lagerstätte is remarkable for its unique soft−bodied fauna (e.g., worms, coleoid squids) and its exceptionally preserved arthropods mainly found in small sideritic concretions. This arthropod fauna includes 30 different species assigned to the crustaceans, the thylacocephalans and the pycnogonids. Crustaceans are the most diversified group with 23 species distributed in a dozen families. Quantitative analyses based on 388 nodules reveals four dominant groups: (i) the enigmatic thylacocephalan arthropods (33%), (ii) the Solenoceridae shrimps (22%), (iii) the Coleiidae crustaceans (15%), and (iv) the Penaeidae shrimps (10%). Converging lines of evidence from depositional environment and modern analogues, indicate that this arthropod fauna probably inhabited a deep water setting most probably exceeding 200 m (= bathyal zone) under dysphotic or aphotic conditions. This new set of data sheds new light on the deep−sea colonisation by animal communities in the Mesozoic.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Jurassic and Cretaceous gastropods from hydrocarbon seeps in forearc basin and accretionary prism settings, California
Autorzy:
Kiel, S.
Campbell, K.A.
Elder, W.P.
Little, C.T.S.
Powiązania:
https://bibliotekanauki.pl/articles/20093.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Jurassic
Cretaceous
gastropod
hydrocarbon seep
forearc basin
accretionary prism setting
California
paleontology
Gastropoda
Great Valley Group
Franciscan Complex
deep water
Opis:
Fourteen gastropod species from 16 Mesozoic hydrocarbon seep carbonate deposits of the Great Valley Group and Franciscan Complex in California are described. Two genera are new: Bathypurpurinopsis has a fusiform shell with a siphonal fold, and variable Paskentana has turbiniform or littoriniform shells with spiral and/or scaly sculpture and convex or shouldered whorls. Due to the lack of data on shell microstructure and protoconch morphology, many of our taxonomic assignments have to remain tentative at present. Species that are described as new include: Hokkaidoconcha bilirata, H. morenoensis, H. tehamaensis (Hokkaidoconchidae), Abyssochrysos? giganteum (Abyssochrysidae?), Paskentana globosa, P. berryessaensis, and Bathypurpurinopsis stantoni (Abyssochrysoidea, family uncertain). The total fauna represents a mixed bag of taxa that were: (i) widely distributed during the late Mesozoic (Amberleya); (ii) restricted to late Mesozoic seep carbonates in California (Atresius, Bathypurpurinopsis, Paskentana); and (iii) members of seep/deep−sea groups with a long stratigraphic range (abyssochrysids, hokkaidoconchids).
Źródło:
Acta Palaeontologica Polonica; 2008, 53, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The teeth of the unenlagiine theropod Buitreraptor from the Cretaceous of Patagonia, Argentina, and the unusual dentition of the Gondwanan dromaeosaurids
Autorzy:
Gianechini, F.A.
Makovicky, P.J.
Apesteguia, S.
Powiązania:
https://bibliotekanauki.pl/articles/20408.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
tooth
unenlagiine theropod
theropod
Buitreraptor
Cretaceous
Patagonia
Argentina
dentition
Gondwanan dromaeosaurid
dromaeosaurid
Theropoda
Dromaeosauridae
Unenlagiinae
Dinosauria
paleontology
dinisaur tooth
Opis:
The Unenlagiinae is a clade of Gondwanan dromaeosaurid theropods mainly known from incomplete skeletal material. The group includes two recently discovered theropods, Buitreraptor and Austroraptor, from which cranial remains are available with in situ maxillary and dentary teeth, thus allowing the study of tooth morphology. Among the derived traits that diagnose the dentition of unenlagiines are: (i) high tooth count, (ii) small size of individual teeth when compared with skull height, (iii) absence of denticles and carinae, and (iv) presence of longitudinal grooves on the tooth crown. This suite of dental characteristics, shared between Buitreraptor and Austroraptor, can be considered as diagnostic of the Unenlagiinae or, at least, a more exclusive clade within the group. The teeth of Buitreraptor exhibit a remarkable labiolingual compression, whereas Austroraptor possesses more conical teeth, probably respective autapomorphic features. On one hand, these dental morphologies differ from those observed in most Laurasian dromaeosaurids and, for instance, could be considered as further proof of the purported vicariant evolution of the lineage on the southern continents. On the other hand, the morphological similarities (e.g., absence of denticles) between the teeth of unenlagiines and other theropod lineages, including Mesozoic birds and ornithomimosaurs, can be considered as the result of parallel trends related to dental reduction.
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New earliest Tiffanian [Late Paleocene] mammals from Cochrane 2, Southwestern Alberta, Canada
Autorzy:
Scott, C S
Fox, R.C.
Youzwyshyn, G.P.
Powiązania:
https://bibliotekanauki.pl/articles/21452.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Paleocene
Late Paleocene
Eutheria
mammal
Canada
new combination
Litomylus grandaletes
Alberta
Ptilodus gnomus
Baiotomeus russelli
Paleotomus junior
fossil
Thryptacodon orthogonius
Paskapoo Formation
Bessoecetor septentrionalis
Pararyctes rutherfordi
new species
paleontology
Multituberculata
Opis:
New mammalian fossils at Cochrane 2, Paskapoo Formation, Alberta, Canada, document five new species and two new combinations: Ptilodus gnomus sp.nov.and Baiotomeus russelli sp.nov.(Multituberculata), Thryptacodon orthogonius comb.nov.and Litomylus grandaletes sp.nov.(“Condylarthra”), Pararyctes rutherfordi sp.nov., Bessoecetor septentrionalis comb.nov., and Paleotomus junior sp.nov.(Eutheria incertae sedis).These new taxa supplement a taxonomically diverse Cochrane 2 local fauna, representing one of the most species rich Paleocene mammalian localities in the world. An earliest Tiffanian age is estimated for the locality based on the presence of the index taxa Plesiadapis praecursor, Nannodectes intermedius, and Ectocion collinus.The Cochrane 2 local fauna fails to demonstrate a decrease in species number relative to those of late Torrejonian localities from the United States, as would be predicted by current paleoclimate scenarios; the rarity of earliest Tiffanian localities in North America suggests sampling error as a partial explanation for the apparent incongruity.
Źródło:
Acta Palaeontologica Polonica; 2002, 47, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temporal dynamics of the geographic differentiation of Late Devonian Palmatolepis assemblages in the Prototethys
Autorzy:
Girard, C.
Ta, H.P.
Savage, N.
Renaud, S.
Powiązania:
https://bibliotekanauki.pl/articles/22384.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
temporal dynamics
geographic differentiation
Late Devonian
Palmatolepis
Prototethys zob.Proto-Tethys Ocean
Proto-Tethys Ocean
Conodonta
mass extinction
morphometry
Frasnian
Famennian
Opis:
Throughout their history, species had to face environmental variations spatially and temporally. How both levels of variation interact will be of key importance in conditioning their response to major perturbations. We addressed this question by focusing on a period in Earth’s history marked by dramatic environmental and faunal changes, the Late Devonian Frasnian/Famennian boundary. From a paleogeographic point of view, this period is characterized by a cosmopolitanism of the faunas across a large ocean, the Prototethys. We considered the biotic reaction at a seldom considered scale, namely within a single subgenus of conodont, Palmatolepis (Manticolepis). Patterns of spatial and temporal differentiation were quantified using morphometrics of its platform element. The recognized cosmopolitanism of the faunas was confirmed at this scale of variation since temporal records gathered in distant areas around the Prototethys, including the seldom documented regions located nowadays in South−East Asia, displayed similar morphological trends in response to the major F/F crisis. Beyond this overall cosmopolitanism, subtle geographic structure was evidenced but was not stable through time. Geographic differentiation was maximal shortly before the F/F crisis, suggesting that despite high sea−level, tectonics leaded to complex submarine landscapes promoting differentiation. In contrast any geographic structure was swamped out after the crisis, possibly due to a global recolonization from few favorable patches.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phosphatised olenid trilobites and associated fauna from the Upper Cambrian of Vastergotland, Sweden
Autorzy:
Ahlberg, P
Szaniawski, H.
Clarkson, E.N.K.
Bengtson, S.
Powiązania:
https://bibliotekanauki.pl/articles/19975.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
trilobite
Trilobita
Vastergotland
Olenidae
Sweden
Upper Cambrian
Cambrian
phosphatization
paleontology
Opis:
Secondarily phosphatised olenid trilobites from organic−rich limestones (orsten) in the Furongian (Upper Cambrian) of Västergötland, south−central Sweden, are described and illustrated. All trilobites originate from the Peltura scarabaeoides Zone and were collected on the western slope of Kinnekulle. Only the dorsal exoskeletons have become secondarily phosphatised, and the ventral appendages are not preserved. Yet the material is otherwise remarkably well preserved and reveals the morphology of the olenid trilobites in greater detail than hitherto known. Species belonging to the genera Ctenopyge, Sphaerophthalmus, Parabolina, and Peltura are identified, and several juvenile specimens are present in the material. The material is disarticulated and fragmentary, and it has only been possible to identify a few specimens to species level. In addition to chaetognaths and conodonts, the trilobites are associated with pelmatozoan columnals, a possible camaroid, and fossils of uncertain affinities. These fossils, along with a probable conulariid fragment from the Peltura minor Zone, are also described and discussed. The presence of a benthic fauna of pelmatozoans, and possible conulariids and camaroids, indicates that at least parts of the Peltura zones were deposited during dysoxic rather than anoxic periods. Moreover, the sea floor must have been firm enough to allow colonisation by sessile organisms.
Źródło:
Acta Palaeontologica Polonica; 2005, 50, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł

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