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Tytuł:
Therian femora from the Late Cretaceous of Uzbekistan
Autorzy:
Chester, S.G.B.
Sargis, E.J.
Szalay, F.S.
Archibald, J.D.
Averianov, A.O.
Powiązania:
https://bibliotekanauki.pl/articles/20995.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Theria
femur
Late Cretaceous
Uzbekistan
Metatheria
Eutheria
Zhelestidae
Zalambdalestidae
Cretaceous
paleontology
Opis:
Femora referable to metatherians and eutherians recovered from the Bissekty Formation, Dzharakuduk, Kyzylkum Desert, Uzbekistan (90 Mya), are described. Fourteen isolated specimens were sorted based on size and morphology into groups that likely correspond to the species level or higher. Groups were then tentatively assigned to taxa known from teeth, petrosals, and/or other postcrania at these localities. One distal femur of a small arboreal metatherian, and several eutherian distal femora that probably represent zhelestids and/or zalambdalestids were identified. With the exception of one proximal femur that is similar in some aspects to the zalambdalestid Barunlestes, and a previously described multituberculate specimen, all other proximal femora from the Bissekty Formation exhibit a metatherian−like morphology. The dental record currently suggests the presence of twelve eutherian species and only one metatherian at Dzharakuduk, whereas the humeral and crurotarsal evidence supports the presence of at least two or four metatherian species, respectively. Given the sample size of the proximal femora, the morphological diversity present, and the overwhelming presence of eutherians at these localities, it is highly unlikely that the overwhelming majority of proximal femora actually represent metatherians. Therefore, this sample may suggest that the metatherian proximal femoral condition is primitive for Theria and that some eutherian taxa (probably including Zhelestidae, which are dentally most abundant at these localities) retain this condition.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aspects of life mode among Ordovician asteroids: Implications of new specimens from Baltica
Autorzy:
Blake, D B
Rozhnov, S.
Powiązania:
https://bibliotekanauki.pl/articles/22238.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
asteroid
Echinodermata
Ordovician
Asteroidea
new species
new genus
Estoniaster maennili
paleontology
functional morphology
Estonia
Opis:
A new genus and species of Asteroidea (Echinodermata), Estoniaster maennili, is described from the Upper Ordovician (Caradocian) of Estonia; it is similar to the western European genus Platanaster and the North American Lanthanaster and an as yet unpublished new genus. Specimens of Urasterella? sp. and Cnemidactissp. are recognized from the Middle Ordovician of northwest Russia; although similar to known species, incomplete preservation precludes more precise taxonomic assessment. Asteroids are important in many existing marine communities, and in spite of a meager fossil record, diversity suggests they were important in the early Paleozoic as well. Some debate has centered on arm flexibility in early asteroids, which bears on their roles in their communities. Parallels in ambulacral series arrangement between Ordovician and extant species and presence of an ambulacral furrow indicate similar broad ranges of motion and therefore potentially parallel ecologic roles. Many factors might have contributed to the differences between ancient and extant ambulacral articulation, including changes in positioning of a part of the water vascular system, changes in predation and bioturbation pressures, and taphonomic events that obscure skeletal details.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The oldest isorophid edrioasteroid [Echinodermata] and the evolution of attachment strategies in Cambrian edrioasteroids
Autorzy:
Zamora, S
Smith, A.B.
Powiązania:
https://bibliotekanauki.pl/articles/20753.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
isorophid edrioasteroid
Echinodermata
evolution
attachment strategy
Cambrian
edrioasteroid
Isorophida
Edrioasteroidea
Spain
Opis:
Two new middle Cambrian edrioasteroid (Echinodermata), Protorophus hispanicus gen. et sp. nov., and Isorophida gen. et sp. indet., are described from the early middle Cambrian (Cambrian Series 3, Stage 5) of Spain. These are the oldest and probably the most primitive isorophids, a clade previously known from the upper Cambrian onwards. Specimens are attached to trilobite fragments indicating that edrioasteroids had by this time separated into two lineages each with different strategies for attachment, sediment attachers and hard substrate attachers. The single U−shaped ambulacral flooring plates of Protorophus are unique while Isorophida gen. et sp. indet. shares the presence of spines in common with some pyrgocystitid isorophids. The shift from facultative soft−bottom attachment to obligate hard−ground attachment in edrioasteroids involved the retention of a juvenile trait into adulthood and was already underway by the middle Cambrian.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 3; 487-494
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new Middle Cambrian stem-group echinoderm from Spain: Palaeobiological implications of a highly asymmetric cinctan
Autorzy:
Zamora, S
Smith, A.B.
Powiązania:
https://bibliotekanauki.pl/articles/22838.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleobiology
new species
Homostelea
Spain
paleontology
Echinodermata
functional morphology
asymmetric body
Middle Cambrian
echinoderm
Lignanicystis barriosensis
carpoid
Opis:
A new exquisitely preserved stem group echinoderm (cinctan), Lignanicystis barriosensis gen. et sp. nov., is described from the Middle Cambrian of Los Barrios de Luna, North Spain. This displays a unique asymmetrical body plan with ventral projecting nodes that raised the lower surface above the substratum. There are four openings through the body wall: mouth, anus, atrium, and an aligned row of sutural pores of uncertain function. Unlike other cinctans, Lignanicystis has a strongly asymmetrical shape convergent with that of some cornute carpoids. Like cornutes, the test is also elevated above the substratum to allow water flow beneath the theca. In both cases this is probably an adaptation to life in higher water flow regimes.
Źródło:
Acta Palaeontologica Polonica; 2008, 53, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Small shelly fossils from the argillaceous facies of the Lower Cambrian Forteau Formation of Western Newfoundland
Autorzy:
Skovsted, C.B.
Peel, J.S.
Powiązania:
https://bibliotekanauki.pl/articles/20504.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Brachiopoda
Cambrian
Forteau Formation
geological setting
Helcionellidae
Hyolitha
Lower Cambrian
Newfoundland
argillaceous facies
brachiopod
facies
fossil
helcionelloid mollusc
hyolith
mollusc
paleontology
small shelly fossil
systematics
Opis:
A diverse fauna of helcionelloid molluscs, hyoliths, and other small shelly fossils is described from limestone layers within the Forteau Formation of the Bonne Bay region in western Newfoundland. The fauna is dominated by internal moulds of various molluscs and tubular problematica, but also includes hyolith opercula, echinoderm ossicles, and other calcareous small shelly fossils preserved by phosphatisation. Originally organophosphatic shells are comparatively rare, but are represented by brachiopods, hyolithelminths, and tommotiids. The fauna is similar to other late Early Cambrian faunas from slope and outer shelf settings along the eastern margin of Laurentia and may be of middle Dyeran age. The similarity of these faunas indicates that at least by the late Early Cambrian, a distinctive and laterally continuous outer shelf fauna had evolved. The Forteau Formation also shares elements with faunas from other Early Cambrian provinces, strengthening ties between Laurentia and Australia, China, and Europe during the late Early Cambrian. Two new taxa of problematic fossil organisms are described, the conical Clavitella curvata gen. et sp. nov. and the wedge−shaped Sphenopteron boomerang gen. et sp. nov.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 4
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:
Helodermatid lizard from the Mio-Pliocene oak-hickory forest of Tennessee, eastern USA, and a review of monstersaurian osteoderms
Autorzy:
Mead, J.I.
Schubert, B.W.
Wallace, S.C.
Swift, S.L.
Powiązania:
https://bibliotekanauki.pl/articles/20494.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
helodermatid lizard
lizard
Miocene
oak-hickory forest
Tennessee
USA
monstersaurian osteoderm
osteoderm
Reptilia
Squamata
Helodermatidae
Heloderma
beaded lizard
Hemphillian
Pliocene
North America
paleontology
Opis:
The extant venomous Gila monster and beaded lizards, species of Heloderma, live today in southwestern USA and south along the Pacific coastal region into Central America, but their fossil history is poorly understood. Here we report helodermatid osteoderms (dermal ossicles) from the late Miocene–early Pliocene Gray Fossil Site, eastern Tennessee USA. Twenty−three species of mammals are known from the fauna including abundant Tapirus polkensis, as well as fishes, anurans, salamanders, turtles, Alligator, birds, and snakes. Beaded lizards belong to the Monstersauria, a clade that includes Primaderma + Paraderma + Gobiderma + Helodermatidae (Estesia, Eurheloderma, Lowesaurus, and Heloderma). Osteoderms of lizards in this clade are unique within Squamata; they typically are circular to polygonal in outline, domed to flat−domed in cross−section, have a vermiculate surface texture, are not compound structures, and do not have imbricate surfaces as on many scincomorph and anguid lizards. We review and characterize the osteoderms of all members of Monstersauria. Osteoderms from the cranium, body, and limbs of Heloderma characteristically have a ring−extension (bony flange) at least partly surrounding the dome. Its presence appears to be a key character distinct to all species of Heloderma, consequently, we propose the presence of a ring−extension to be an apomorphy. Three osteoderms from the Gray Fossil Site range from 1.5 to 3.0 mm in diameter, have the circular shape of helodermatid osteoderms with a domed apical surface, and have the ring−extensions, permiting generic identification. Macrobotanical remains from the Gray Fossil Site indicate an oak−hickory subtropical forest dominated by Quercus (oak) and Carya (hickory) with some conifer species, an understorey including the climbing vines Sinomenium, Sargentodoxa, and Vitis. Plant and mammal remains indicate a strong Asian influence.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The systematics of Late Jurassic tyrannosauroid theropods from Europe and North America
Autorzy:
Brusatte, S.L.
Benson, R.B.J.
Powiązania:
https://bibliotekanauki.pl/articles/22629.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
systematics
Late Jurassic
tyrannosauroid theropod
theropod
Europe
North America
Dinosauria
Theropoda
Tyrannosauridae
Tyrannosaurus
anatomy
Jurassic
paleontology
Opis:
Recent discoveries of more than ten new species of tyrannosauroid theropods are helping to understand the origin and evolu− tion of colossal body size and other characteristic features of Tyrannosaurus rex and its terminal Cretaceous relatives. Partic− ularly important has been the discovery and reinterpretation of Late Jurassic tyrannosauroids from Europe and North Amer− ica, which are intermediate in size and phylogenetic position between small basal tyrannosauroids and the largest Late Cre− taceous species. The fragmentary nature of these Jurassic specimens, however, has frustrated attempts to understand their systematics and phylogeny. A new specimen from the Late Jurassic of England was recently named as a new species (Stokesosaurus langhami) of the genus Stokesosaurus, which is known from several fragmentary fossils from North Amer− ica. We review the systematics and phylogeny of these European and North American specimens and show that there are no unequivocal synapomorphies uniting them. Furthermore, a revised phylogenetic analysis does not recover them as sister taxa. This necessitates a taxonomic revision of this material, and we name a new genus (Juratyrant) for theBritish specimen.
Źródło:
Acta Palaeontologica Polonica; 2013, 58, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new dyrosaurid crocodyliform from the Paleocene of Morocco and a phylogenetic analysis of Dyrosauridae
Autorzy:
Jouve, S
Iarochene, M.
Bouya, B.
Amaghzaz, M.
Powiązania:
https://bibliotekanauki.pl/articles/20369.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Ouled Abdoun Basin
Paleocene
dyrosaurid crocodyliform
Dyrosauridae
Crocodyliformes
Arambourgisuchus khouribgaensis
new species
new genus
Morocco
paleontology
Opis:
A new genus and species belonging to Dyrosauridae, Arambourgisuchus khouribgaensis, from the Thanetian (Palaeocene) of Morocco, is erected. Two more or less complete skulls and three mandibular fragments enable a reconstruction of the anatomical characteristics of this species. Dyrosaurid systematics is mainly based on mandibular characters. The comparison of this new material with several dyrosaurid species previously known provides new systematic data for this group. The width of the interfenestral bar, the shape and development of the occipital tuberosities and the shape of the supraoccipital and the basioccipital are of particular importance. A phylogenetic analysis of the dyrosaurids provides an outline of the relationships between the best known species. Chenanisuchus lateroculi is the most primitive dyrosaurid. Sokotosuchus ianwilsoni and Phosphatosaurus gavialoidesform a clade, more closely related to other dyrosaurids than to Chenanisuchus lateroculi. The relationships between Arambourgisuchus, Rhabdognathus, Congosaurus, and Hyposaurus are unclear, and the two latter taxa remain too poorly known to provide an uncontested phylogenetic result. The dyrosaurids are known from nearly all continents. The phylogenetic results suggest a North African range for basal members, and the wide distribution of Rhabdognathus and Hyposaurus confirms the possibility of transoceanic dispersal of these taxa. Unfortunately, many dyrosaurids are insufficiently known to be included in the analysis, and the present analysis considers mainly African forms. A better knowledge and the inclusion of other taxa from other geographic regions should significantly improve and modify the hypothesis.
Źródło:
Acta Palaeontologica Polonica; 2005, 50, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A termite from the Late Oligocene of northern Ethiopia
Autorzy:
Engel, M.S.
Pan, A.D.
Jacobs, B.F.
Powiązania:
https://bibliotekanauki.pl/articles/20549.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
termite
Late Oligocene
Ethiopia
Stolotermitidae
fossil record
geological setting
paleontology
Chilgatermes diamatensis
Opis:
Termites of the family Stolotermitidae are a relict lineage of primitive Isoptera. The fossil record of Stolotermitidae is exceptionally poor, with only two Miocene (Neogene) species documented to date. Herein, a new genus and species of Paleogene termites is described and figured from the Late Oligocene (28–27 Ma, Early Chattian) of northwestern Ethiopia (Amhara Region, Chilga Woreda). Chilgatermes diamatensis gen. et sp. nov., is most similar to genera of the Stolotermitidae, Archotermopsidae, and Termopsidae but can be distinguished on the basis of forewing venational details. The genus is tentatively placed in the Stolotermitidae: Porotermitinae. Chilgatermes diamatensis is the first fossil termite from Ethiopia and, indeed, the first from the entire African continent.
Źródło:
Acta Palaeontologica Polonica; 2013, 58, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Youngest occurrences of rhomaleosaurid plesiosaurs indicate survival of an archaic marine reptile clade at high palaeolatitudes
Autorzy:
Benson, R.B.J.
Zverkov, N.G.
Arkhangelsky, M.S.
Powiązania:
https://bibliotekanauki.pl/articles/21817.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Plesiosauria
Rhomaleosauridae
biogeography
Jurassic
Callovian
occurrence
rhomaleosaurid plesiosaur
survival
marine reptile
paleontology
United Kingdom
Russia
Opis:
Rhomaleosaurid plesiosaurians were a common and ecologically significant component of Early Jurassic marine faunas, primarily as large-bodied predators. They declined in abundance and made their last fossil appearance in the Middle Jurassic. However, the geographic pattern of rhomaleosaurid extinction has thus far been obscured by spatial bias in the Middle Jurassic marine reptile fossil record, which is strongly focussed on low-latitude European assemblages. We report two rhomaleosaurid specimens from the Callovian (late Middle Jurassic) of the UK and Russia. Along with Borealonectes from Arctic Canada, these are the youngest-known occurrences of rhomaleosaurids. The UK specimen is the first identified from the Callovian of Europe, despite intensive fossil sampling over almost 200 years and the recovery of hundreds of other plesiosaurian specimens. Its discovery indicates that rhomaleosaurids were present, but extremely rare, at low palaeolatitudes of the Callovian. The Russian specimen is one of relatively few marine reptile specimens from its mid-palaeolatitude assemblage, as is also true of Borealonectes, which occurs in a high-palaeolatitude marine assemblage. Furthermore, we suggest that a mid latitude southern hemisphere occurrence from the Callovian of Argentina, previously referred to Pliosauridae, in fact represents a rhomaleosaurid. These findings suggest that rhomaleosaurids were actually common elements of mid-high palaeolatitude marine faunas, indicating a geographically staggered pattern of declining rhomaleosaurid abundance, and demonstrating the apparent persistence of an archaic marine reptile group in cool, mid-high latitude environments of the Middle Jurassic. It is therefore possible that sustained Middle-Late Jurassic global warming accelerated the ultimate extinction of rho-maleosaurids. Our findings suggest that widening the geographical breadth of fossil exploration could considerably enhance current knowledge of Jurassic marine reptile evolution.
Źródło:
Acta Palaeontologica Polonica; 2015, 60, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A reassessment of Kelmayisaurus petrolicus, a large theropod dinosaur from the Early Cretaceous of China
Autorzy:
Brusatte, S.L.
Benson, R.B.J.
Xu, X.
Powiązania:
https://bibliotekanauki.pl/articles/21593.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
Kelmayisaurus petrolicus
large theropod dinosaur
theropod dinosaur
Early Cretaceous
China
Dinosauria
Theropoda
Carcharodontosauridae
anatomy
Cretaceous
Opis:
The Early Cretaceous fossil record of large−bodied theropods from Asia is poor, hindering comparison of Asian predatory dinosaur faunas with those from other continents. One of the few large Asian theropod specimens from this interval is a partial skull (maxilla and dentary) from the Lianmugin Formation (?Valanginian–Albian), the holotype of Kelmayisaurus petrolicus. Most authors have either considered this specimen as an indeterminate basal tetanuran or a nomen dubium. We redescribe K. petrolicus and note that it possesses a single autapomorphy (a deep accessory groove on the lateral surface of the anterior dentary), as well as a unique combination of characters that differentiates it from other theropods, affirming its validity. A phylogenetic analysis recovers K. petrolicus as a basal carcharodontosaurid, which is supported by various features: very deep interdental plates (a carcharodontosaurid synapomorphy), fused interdental plates (present in carchardontosaurids and a limited number of other theropods), and the absence of diagnostic features of other clades of large−bodied theropods such as abelisaurids, megalosauroids, and coelurosaurs. As such,Kelmayisaurusis the second known carcharodontosaurid from Asia, and further evidence that this clade represented a global radiation of large−bodied predators during the Early–mid Cretaceous.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biodiversity evolution through the Permian-Triassic boundary event: Ostracods from the Bükk Mountains, Hungary
Autorzy:
Forel, M.-B.
Crasquin, S.
Hips, K.
Kershaw, S.
Collin, P.-Y.
Haas, J.
Powiązania:
https://bibliotekanauki.pl/articles/23146.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
biodiversity
evolution
Permian
Triassic
ostracod
Ostracoda
Bukk Mountains
geological setting
paleontology
systematics
Hungary
Opis:
One of the most complete Permian–Triassic boundary sections located in the Bükk Mountains (Hungary) was sampled for ostracod study. Seventy−six species are recognized, belonging to twenty genera. Fifteen new species are described and figured: Acratia? jeanvannieri Forel sp. nov., Acratia nagyvisnyoensis Forel sp. nov., Bairdia anisongae Forel sp. nov., Bairdia davehornei Forel sp. nov., Callicythere? balvanyseptentrioensis Forel sp. nov., Cytherellina? magyarorsza− gensis Forel sp. nov., Eumiraculum desmaresae Forel sp. nov., Hollinella fengqinglaii Crasquin sp. nov., Hungarella gerennavarensis Crasquin sp. nov., Langdaia bullabalvanyensis Crasquin sp. nov., Liuzhinia venninae Forel sp. nov., Liuzhinia bankutensis Forel sp. nov., Microcheilinella egerensis Forel sp. nov., Reviya praecurukensis Forel sp. nov., Shemonaella? olempskaella Forel sp. nov. One species is renamed: Bairdia baudini Crasquin nom. nov. Comparison of the Bálvány North section with the Meishan section (Zhejiang Province, South China), Global Boundary Stratotype Sec− tion and Point (GSSP) of the Permian–Triassic Boundary (PTB), reveals discrepancies linked to the environmental set− ting and particularly to bathymetry. The stratigraphical distribution of all the species is given and diversity variations are discussed. The Bálvány North section exhibits the lowest extinction rate of all PTB sections studied for ostracods analysis associated with a high level of endemism.
Źródło:
Acta Palaeontologica Polonica; 2013, 58, 1
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:
A dental microwear texture analysis of the Mio-Pliocene hyaenids from Langebaanweg, South Africa
Autorzy:
Stynder, D.D.
Ungar, P.S.
Scott, J.R.
Schubert, B.W.
Powiązania:
https://bibliotekanauki.pl/articles/23002.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
dental microwear texture
Mio-Pliocene
Hyaenidae
Langebaanweg
South Africa
Mammalia
durophagy
diet
foraging strategy
Hyaenictitherium namaquensis Ikelohyaena abronia
Chasmaporthetes australis
Hyaenictis hendeyi
Crocuta crocuta
Acinonyx jubatus
Panthera leo
paleontology
hyaenid species
Opis:
Hyaenids reached their peak diversity during the Mio−Pliocene, when an array of carnivorous species emerged alongside dwindling civet−like and mongoose−like insectivorous/omnivorous taxa. Significantly, bone−cracking morphological adaptations were poorly developed in these newly−emerged species. This, their general canid−like morphology, and the absence/rarity of canids in Eurasia and Africa at the time, has led researchers to hypothesise that these carnivorous Mio−Pliocene hyaenas were ecological vicars to modern canids. To shed further light on their diets and foraging strategies, we examine and compare the dental microwear textures of Hyaenictitherium namaquensis, Ikelohyaena abronia, Chasmaporthetes australis, and Hyaenictis hendeyi from the South African Mio−Pliocene site of Langebaanweg with those of the extant feliforms Crocuta crocuta, Acinonyx jubatus, and Panthera leo (caniforms are not included because homologous wear facets are not directly comparable between the suborders). Sample sizes for individual fossil species are small, which limits confidence in assessments of variation between the extinct taxa; however, these Mio−Pliocene hyaenas exhibit surface complexity and textural fill volume values that are considerably lower than those exhibited by the living hyaena, Crocuta crocuta. Dental microwear texture analysis thus supports interpretations of craniodental evidence suggesting low bone consumption in carnivorous Mio−Pliocene hyaenas.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł

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