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Wyszukujesz frazę "Maastrichtian" wg kryterium: Temat


Wyświetlanie 1-9 z 9
Tytuł:
Theropod teeth from the upper Maastrichtian Hell Creek Formation “Sue” Quarry: New morphotypes and faunal comparisons
Autorzy:
Gates, T.A.
Zanno, L.E.
Makovicky, P.J.
Powiązania:
https://bibliotekanauki.pl/articles/945614.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
theropod
tooth
Upper Maastrichtian
Maastrichtian
Hell Creek Formation
morphotype
Dinosauria
morphometry
paleoecology
Cretaceous
North America
Opis:
Isolated teeth from vertebrate microfossil localities often provide unique information on the biodiversity of ancient ecosystems that might otherwise remain unrecognized. Microfossil sampling is a particularly valuable tool for documenting taxa that are poorly represented in macrofossil surveys due to small body size, fragile skeletal structure, or relatively low ecosystem abundance. Because biodiversity patterns in the late Maastrichtian of North American are the primary data for a broad array of studies regarding non-avian dinosaur extinction in the terminal Cretaceous, intensive sampling on multiple scales is critical to understanding the nature of this event. We address theropod biodiversity in the Maastrichtian by examining teeth collected from the Hell Creek Formation locality that yielded FMNH PR 2081 (the Tyrannosaurus rex specimen “Sue”). Eight morphotypes (three previously undocumented) are identified in the sample, representing Tyrannosauridae, Dromaeosauridae, Troodontidae, and Avialae. Noticeably absent are teeth attributed to the morphotypes Richardoestesia and Paronychodon. Morphometric comparison to dromaeosaurid teeth from multiple Hell Creek and Lance formations microsites reveals two unique dromaeosaurid morphotypes bearing finer distal denticles than present on teeth of similar size, and also differences in crown shape in at least one of these. These findings suggest more dromaeosaurid taxa, and a higher Maastrichtian biodiversity, than previously appreciated.
Źródło:
Acta Palaeontologica Polonica; 2015, 60, 1; 131-139
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The lambeosaurine dinosaur Amurosaurus riabinini, from the Maastrichtian of Far Eastern Russia
Autorzy:
Godefroit, P
Bolotsky, Y.L.
Van Itterbeeck, J.
Powiązania:
https://bibliotekanauki.pl/articles/21185.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
phylogenesis
Late Cretaceous
Dinosauria
Russia
dinosaur
Amurosaurus riabinini
paleogeography
Maastrichtian
paleontology
Lambeosaurinae
Opis:
Amurosaurus riabinini Bolotsky and Kurzanov, 1991 (Dinosauria, Hadrosauridae) is described on the basis of numerous disarticulated bones from the Maastrichtian Udurchukan Formation of Blagoveschensk, Far Eastern Russia. Comparisons with North American palynozones and their well−calibrated ages suggest that this formation is late Maastrichtian in age. It is shown that A. riabinini is a valid species, characterised by cranial and postcranial autapomorphies. A phylogenetic analysis, based on 40 cranial, dental, and postcranial characters, indicates that this taxon occupies a relatively basal position within the lambeosaurine subfamily as the sister−taxon of a monophyletic group formed by the parasauroloph and corythosaur clades. This cladogram also demonstrates that lambeosaurines have an Asian origin. In eastern Asia, lambeosaurine dinosaurs dominate late Maastrichtian dinosaur localities, whereas this group is apparently no longer represented in synchronous localities from western North America.
Źródło:
Acta Palaeontologica Polonica; 2004, 49, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new Arctic hadrosaurid from the Prince Creek Formation (lower Maastrichtian) of northern Alaska
Autorzy:
Mori, H.
Druckenmiller, P.S.
Erickson, G.M.
Powiązania:
https://bibliotekanauki.pl/articles/23525.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
new species
Arctic
hadrosaurid
Dinosauria
Hadrosauridae
Saurolophinae
Edmontosaurini
ontogenesis
Cretaceous
Prince Creek Formation
Maastrichtian
Alaska
Opis:
The Liscomb bonebed in the Price Creek Formation of northern Alaska has produced thousands of individual bones of a saurolophine hadrosaurid similar to Edmontosaurus; however, the specific identity of this taxon has been unclear, in part because the vast majority of the remains represent immature individuals. In this study, we address the taxonomic status of the Alaskan material through a comparative and quantitative morphological analysis of juvenile as well several near adult-sized specimens with particular reference to the two known species of Edmontosaurus, as well as a cladistic analysis using two different matrices for Hadrosauroidea. In the comparative morphological analysis, we introduce a quantitative method using bivariate plots to address ontogenetic variation. Our comparative anatomical analysis reveals that the Alaskan saurolophine possesses a unique suite of characters that distinguishes it from Edmontosaurus, including a premaxillary circumnarial ridge that projects posterolaterally without a premaxillary vestibular promontory, a shallow groove lateral to the posterodorsal premaxillary foramen, a relatively narrow jugal process of the postorbital lacking a postorbital pocket, a relatively tall maxilla, a relatively gracile jugal, a more strongly angled posterior margin of the anterior process of the jugal, wide lateral exposure of the quadratojugal, and a short symphyseal process of the dentary. The cladistic analyses consistently recover the Alaskan saurolophine as the sister taxon to Edmontosaurus annectens + Edmontosaurus regalis. This phylogenetic assessment is robust even when accounting for ontogenetically variable characters. Based on these results, we erect a new taxon, Ugrunaaluk kuukpikensis gen. et sp. nov. that contributes to growing evidence for a distinct, early Maastrichtian Arctic dinosaur community that existed at the northernmost extent of Laramidia during the Late Cretaceous.
Źródło:
Acta Palaeontologica Polonica; 2016, 61, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New elmisaurine specimens from North America and their relationship to the Mongolian Elmisaurus rarus
Autorzy:
Funston, G.F.
Currie, P.J.
Burns, M.E.
Powiązania:
https://bibliotekanauki.pl/articles/22633.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
new species
Elmisaurinae
Dinosauria
Oviraptorosauria
Caenagnathidae
Campanian
Maastrichtian
North America
relationship
Mongolia
Elmisaurus rarus
Opis:
New specimens from Canada confirm the presence of elmisaurines in North America and shed light on the relationship of Leptorhynchos elegans to Mongolian forms. These specimens have hindlimb elements previously unknown from elmisaurines in the Dinosaur Park Formation, including tibiae and pedal phalanges. Metatarsal anatomy is sufficiently different to merit a generic distinction from Elmisaurus rarus, and both can be distinguished from Caenagnathus collinsi and Chirostenotes pergracilis. Differences between these taxa include body size, degree of coossification of the tarsometatarsus, and development of cruciate ridges of the metatarsal III. Histological analysis confirms that these differences are not correlated with ontogenetic age of the specimens. The results support the informal separation of caenagnathids based on metatarsal structure, and allow comments on paleobiological differences between caenagnathids and oviraptorids.
Źródło:
Acta Palaeontologica Polonica; 2016, 61, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theropod tooth assemblages from the Late Cretaceous Maevarano Formation and the possible presence of dromaeosaurids in Madagascar
Autorzy:
Fanti, F
Therrien, F.
Powiązania:
https://bibliotekanauki.pl/articles/20343.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
theropod diversity
Cretaceous
Late Cretaceous
dromaeosaurid
tooth
Maastrichtian
theropod tooth
paleobiogeography
Abelisauridae
Dinosauria
Madagascar
Campanian
paleontology
Dromaeosauridae
Maevarano Formation
Opis:
The latest Cretaceous (Campanian?–Maastrichtian) Maevarano Formation of the Mahajanga Basin, Madagascar, preserves one of the most diverse fossil vertebrate faunas of the Gondwanan landmasses. Over 180 isolated theropod teeth recovered from that formation were studied in order to document theropod diversity in the Madagascar insular setting. Tooth morphology and characteristics of the Maevarano teeth were compared to those of known theropod teeth for identification, including the Malagasy non−avian theropods Majungatholus atopus and Masiakasaurus knopfleri. Tooth and denticle morphologies permit the recognition of five tooth morphotypes: three morphotypes are referable to Majungatholus atopus based on variation in tooth morphology observed in teeth preserved in situ in the jaws of two specimens, and one morphotype is ascribable to Masiakasaurus knopfleri. Teeth pertaining to the fifth morphotype differ from other morphotypes in the size and orientation of the denticles, shape and orientation of blood grooves, and in general tooth morphology. Statistical analyses reveal that the fifth Maevarano tooth morphotype is similar to dromaeosaurid teeth, suggesting that a yet unknown theropod taxon inhabited Madagascar during the latest Cretaceous. This morphotype represents the first evidence of the possible presence of a dromaeosaurid in Madagascar and supports the theory that dromaeosaurids were present throughout Pangaea before the break−up of the supercontinent during the Late Jurassic and had colonized Madagascar before its separation from Africa during the Early Cretaceous.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new Maastrichtian species of the centrosaurine ceratopsid Pachyrhinosaurus from the North Slope of Alaska
Autorzy:
Fiorillo, A.R.
Tykoski, R.S.
Powiązania:
https://bibliotekanauki.pl/articles/23291.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Maastrichtian species
new species
centrosaurine ceratopsid
ceratopsid
Pachyrhinosaurus
Alaska
dinosaur
Pachyrhinosaurus perotorum
Dinosauria
Centrosaurinae
Cretaceous
Prince Creek Formation
Arctic
paleontology
remains
Opis:
The Cretaceous rocks of the Prince Creek Formation contain the richest record of polar dinosaurs found anywhere in the world. Here we describe a new species of horned dinosaur, Pachyrhinosaurus perotorum that exhibits an apomorphic character in the frill, as well as a unique combination of other characters. Phylogenetic analysis of 16 taxa of ceratopsians failed to resolve relationships between P. perotorum and other Pachyrhinosaurusspecies (P. canadensis and P. lakustai). P. perotorum shares characters with each of the previously known species that are not present in the other, including very large nasal and supraorbital bosses that are nearly in contact and separated only by a narrow groove as in P. canadensis, and a rostral comb formed by the nasals and premaxillae as in P. lakustai. P. perotorum is the youngest centrosaurine known (70–69 Ma), and the locality that produced the taxon, the Kikak−Tegoseak Quarry, is close to the highest latitude for recovery of ceratopsid remains.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The titanosaur sauropods from the late Campanian-early Maastrichtian Allen Formation of Salitral Moreno, Rio Negro, Argentina
Autorzy:
Garcia, R.A.
Salgado, L.
Powiązania:
https://bibliotekanauki.pl/articles/20087.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
titanosaur sauropod
sauropod
Dinosauria
Saurischia
Sauropodomorpha
Sauropoda
Titanosauria
Titanosaur
Late Campanian
Early Maastrichtian
Allen Formation
Salitral Moreno
Rio Negro
Argentina
paleontology
Opis:
The dinosaur record of the Salitral Moreno locality (Río Negro Province, Argentina) is characterized by a high diversity of herbivore taxa, among them hadrosaurs, ankylosaurs, and titanosaur sauropods, but carnivores are rare, consisting of only a few fragmentary bones of small forms. Titanosaurs are represented by Rocasaurus muniozi and Aeolosaurus sp., and at least four other taxa, represented by fragmentary material. The elements preserved include a cervical, dorsal and caudal vertebrae, chevron, humerii, ulnae, radii, metacarpal, femora, tibiae, metatarsal, ischia, pubis, and ilium. The Allen Formation is thought to be correlated with the Marília Formation in Brazil, and their faunas have certain elements in common such as aeolosaurines, but saltasaurines and hadrosaurs, are known exclusively from the Allen Formation. These absences, and particularly that of the saltasaurines, may be because those sauropods originated late in the Cretaceous, probably in southern South America (Northern Patagonia?), and they did not have time to disperse to northern South America.
Źródło:
Acta Palaeontologica Polonica; 2013, 58, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Osteology and relationships of Olorotitan arharensis, a hollow−crested hadrosaurid dinosaur from the latest Cretaceous of Far Eastern Russia
Autorzy:
Godefroit, P.
Bolotsky, Y.L.
Bolotsky, I.Y.
Powiązania:
https://bibliotekanauki.pl/articles/20406.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
osteology
relationship
Olorotitan arharensis
dinosaur
hadrosaurid dinosaur
Cretaceous
Russia
Dinosauria
Ornithischia
Hadrosauridae
Lambeosaurinae
phylogenesis
Late Cretaceous
Maastrichtian Udurchukan Formation
Corythosaurus casuarius Hypacrosaurus stebingeri
Hypacrosaurus altispinus
Opis:
The holotype of Olorotitan arharensis from the Maastrichtian Udurchukan Formation in Kundur, Far Eastern Russia, is the most complete dinosaur discovered in Russia and one of the best preserved lambeosaurines outside western North America. This taxon is diagnosed by following autapomorphies: large helmet−like hollow crest higher than the rest of the skull and extending caudally well beyond the level of the occiput; very high postorbital process of jugal (ratio height of postorbital process/length of jugal = 1); rostral portion of the jugal shorter than in other lambeosaurines, with a perfectly straight rostral margin; very asymmetrical maxilla in lateral view, with ventral margin distinctly downturned; very elongated neck composed of 18 cervical vertebrae; tibia as high as the femur; shorter cnemial crest, about one fifth of tibia length. A phylogenetic analysis, based on 118 cranial, dental, and postcranial characters, indicates that Olorotitan is a member of the Corythosaurini clade, and is the sister taxon of Corythosaurus casuarius, Hypacrosaurus stebingeri, and Hypacrosaurus altispinus. The high diversity and mosaic distribution of Maastrichtian hadrosaurid faunas in the Amur−Heilongjiang region are the result of a complex palaeogeographical history and imply that many independent hadrosaurid lineages dispersed readily between western America and eastern Asia at the end of the Cretaceous.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-9 z 9

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