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Tytuł:
A new approach to evaluate the cursorial ability of the giant theropod Giganotosaurus carolinii
Autorzy:
Blanco, R E
Mazzetta, G V
Powiązania:
https://bibliotekanauki.pl/articles/21508.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Cretaceous
Theropoda
Dinosauria
theropod
dinosaur
Giganotosaurus
South America
Giganotosaurus carolinii
Opis:
The cursorial capability of the South American giant theropod Giganotosaurus carolinii should have been quite limited taking into account the strength indicator of its femur (approximately 7 GPa⁻¹) as well as the risk of experiencing grave or even lethal injuries involved in the falling of this multitonne animal on a run. However, even at low speeds a fall would have caused serious injuries. Thus, in accordance to the approach developed in this study, the maximum speed of Giganotosaurus should be not that which will implicate corporal lesions with minimum probability of lethalness. Instead, its maximum speed should be that which would permit the recovery of body equilibrium as each step is taken. Taking into consideration this approach, an indicator of stability is defined for bipedal, cursorial animals. This indicator is determined by the relationship between the time available for the movement of hip joint during the retraction of a hindlimb and the time needed to move the opposite hindlimb by an angle (in function of the speed) of sufficient magnitude as to facilitate the recovery of body equilibrium. This indicator was used to estimate the maximum speed of locomotion of Giganotosaurus (about 14 m s⁻¹) at which, from a kinematic point of view, the danger of falling does not exist.
Źródło:
Acta Palaeontologica Polonica; 2001, 46, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new large-bodied theropod dinosaur from the Middle Jurassic of Warwickshire, United Kingdom
Autorzy:
Benson, R.B.J.
Radley, J.D.
Powiązania:
https://bibliotekanauki.pl/articles/22445.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
large-bodied dinosaur
dinosaur
new dinosaur
theropod dinosaur
Middle Jurassic
Jurassic
Warwickshire
United Kingdom
paleontology
Dinosauria
Theropoda
Tetanurae
Megalosaurus
Cruxicheiros
Bathonian
Chipping Norton Limestone Formation
Opis:
Previously undocumented postcranial material from the Chipping Norton Limestone Formation (Middle Jurassic: Lower Bathonian) of Cross Hands Quarry, near Little Compton, Warwickshire represents a new large−bodied theropod dinosaur, distinct from the contemporaneous Megalosaurus bucklandii. Cruxicheiros newmanorum gen. et sp. nov. is diagnosed by a single autapomorphy, the presence of a proximomedially inclined ridge within the groove that marks the lateral extent of the posterior flange of the femoral caput (trochanteric fossa). C. newmanorum shows three tetanuran features: widely separated cervical zygapophyses, a swollen ridge on the lateral surface of the iliac blade and an anterior spur of the caudal neural spines. However, due to fragmentary preservation its affinities within Tetanurae remain uncertain: phylogenetic analysis places it as the most basal tetanuran, the most basal megalosauroid (= spinosauroid) or the most basal neotetanuran.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new ornithomimid dinosaur with gregarious habits from the Late Cretaceous of China
Autorzy:
Kobayashi, Y
Lu, J.C.
Powiązania:
https://bibliotekanauki.pl/articles/20983.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Cretaceous
Late Cretaceous
Theropoda
Dinosauria
China
Ornithomimosauria
gragarious habit
dinosaur
Ornithomimidae
paleontology
ornithomimid dinosaur
Opis:
At least fourteen ornithomimid skeletons were recovered from the Upper Cretaceous Ulansuhai Formation in Nei Mongol (Inner Mongolia) Autonomous Region of China. They are assigned to a new genus and species, Sinornithomimus dongi. The anatomy of the species is described. Comparative and phylogenetic studies of ornithomimosaurs prove that these skeletons represent a new taxon that is more derived than Archaeornithomimus and more basal than the clade of [(Anserimimus + Gallimimus)+[Struthiomimus + (Dromiceiomimus + Ornithomimus)]]. The phylogenetic analysis suggests that the structure of the hand is similar to Archaeornithomimus and represents an intermediate condition between the primitive (Harpymimus) and the derived (Anserimimus, Gallimimus, Struthiomimus, Dromiceiomimus, and Ornithomimus) conditions. The monophyly of Ornithomimidae is supported by a single synapomorphy (arctometatarsalian condition) in this analysis, indicating that the family is not as strongly supported as previously suggested. The analysis also implies that the shape of the rhamphotheca in North American taxa may have been different from that in Asian taxa. Previous study suggests herbivorous habits of this dinosaur based on characteristics of the gastroliths. The skeletons of Sinornithomimus were collected from a single monospecific bonebed with a high ratio of juvenile individuals (11 of the 14), suggesting gregarious behavior for protection from predators. The abundance of juveniles indicates high mortality of juveniles or a catastrophic mass mortality of a population with a high proportion of juveniles. An increase in the relative ratio of the tibia to femur through the ontogeny of Sinornithomimus suggests higher cursoriality in adult individuals than in juveniles.
Źródło:
Acta Palaeontologica Polonica; 2003, 48, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new oviraptorosaur [Dinosauria, Theropoda] from Mongolia: the first dinosaur with a pygostyle
Nowy owiraptorozaur [Dinosauria, Theropoda] z Mongolii: pierwszy dinozaur z pygostylem
Autorzy:
Barsbold, R
Osmolska, H
Watabe, M
Currie, P J
Tsogtbaatar, K
Powiązania:
https://bibliotekanauki.pl/articles/23298.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
fauna kopalna
Oviraptorosauria
Dinosauria
ogon
terapody
Theropoda
Mongolia
owiraptorozaury
Nomingia gobiensis
kregi
dinozaury
szkielet
paleontologia
pygostyl
pustynia Gobi
Opis:
A description of Nomingia gobiensis gen. et sp. n., the first known dinosaur with a pygostyle, the structure known so far only in birds, is presented. The specimen comes from the Late Cretaceous strata at Bugin Tsav, Trans-Altai Gobi, Mongolia. N. gobiensis is assigned within the Oviraptorosauria based on the following characters: pneumatized caudal vertebrae, posteriorly concave ischium, and deep cervicodorsal hypapophyses. This specimen has been previously partially described without being formally named (Barsbold et al. 2000).
Opisano nowego dinozaura z grupy terapodów, Nomingia gobiensis gen. et sp. n., z osadów wieku późnokredowego Mongolii w Bugin Caw na Gobi Zaałtajskiej. Niekompletny szkielet pozaczaszkowy tego dinozaura został znaleziony na pustyni Gobi, w Mongolii, przez mongolsko-japońską wyprawę paleontologiczną. Najbardziej charakterystyczną cechą N. gobiensis jest zakończony pygostylem i nieco skrócony ogon, liczący tylko 24 kręgi (Sloan 1999; Barsbold et al. 2000). Pygostyl nie był dotychczas znany u żadnego dinozaura i był uważany za cechę swoistą wyłącznie dla ptaków. N. gobiensis został uznany za przedstawiciela Oviraptorosauria o nieustalonej przynależności rodzinowej, wykazuje jednak pewne podobieństwa do słabo poznanego przedstawiciela rodziny Caenagnathidae, Chirostenotes pergracilis Gilmore, 1924.
Źródło:
Acta Palaeontologica Polonica; 2000, 45, 2; 97-106
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new troodontid theropod from the Late Cretaceous of central China, and the radiation of Asian troodontids
Autorzy:
Lu, J
Xu, L.
Liu, Y.
Zhang, X.
Jia, S.
Ji, Q.
Powiązania:
https://bibliotekanauki.pl/articles/20912.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
new theropod
Late Cretaceous
Central China
Asian troodontid
troodontid
Theropoda
Troodontidae
Xixiasaurus
Cretaceous
Henan province
China
paleontology
Opis:
A new troodontid dinosaur, Xixiasaurus henanensis gen. et sp. nov., from the Upper Cretaceous Majiacun Formation of the Xixia Basin, Henan Province, is erected, based on a partial skull. It is characterized by bearing 22 maxillary teeth, a distinct opening on the lateral surface of the base of nasal process of the premaxilla, the rostral end of the upper jaw forming a tapered U−shape, and the mandibular symphyseal region slightly inflected medially. Xixiasaurus is most closely related to the Mongolian Byronosaurus among troodontids. Byronosaurus, Urbacodon, and Xixiasaurus may form a new clade, suggesting an endemic radiation of troodontids across Asia, including multiple taxa without dental serrations. The discovery of Xixiasaurus in the Xixia Basin may imply that the Xixiasaurus−bearing Majiacun Formation is Campanian in age.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 3; 381-388
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:
A tyrannosaurid pedal ungual from the Williams Fork Formation (Campanian) of Colorado and its implications for the biogeography of Laramidian dinosaurs
Autorzy:
Yun, Chan-Gyu
Powiązania:
https://bibliotekanauki.pl/articles/24024717.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
dinosauria
theropoda
tyrannosauridae
fossil record
pedal ungual anatomy
dinosaur biogeography
dinozaury
teropody
tyranozaury
zapis kopalny
anatomia
pazury
biogeografia
Opis:
A right theropod pedal ungual phalanx II-3 from the Campanian Williams Fork Formation of northwestern Colorado is described, and a combination of features, including the large size, tapering distal tip, robust and stout overall form, triangular cross-section, and a relatively flat ventral surface allows a confident referral to Tyrannosauridae Osborn, 1906. Although this specimen was found in a relatively southern state, the proximal articular surface of this ungual is similar to that of Gorgosaurus libratus Lambe, 1914, a taxon found in the northern state, Alberta. Although based on limited evidence, this may suggest that the range of tyrannosaurids considered endemic to the north of Laramidia extended farther south than previously thought.
Źródło:
Acta Geologica Polonica; 2023, 73, 1; 63--72
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Allometric growth in the frontals of the Mongolian theropod dinosaur Tarbosaurus bataar
Autorzy:
Yun, C.-G.
Peters, G.F.
Currie, P.J.
Powiązania:
https://bibliotekanauki.pl/articles/31341395.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
allometric growth
frontal bone
growth change
Mongolia
dinosaur
theropod dinosaur
Tarbosaurus bataar
Dinosauria
Theropoda
Tyrannosauridae
Tyrannosaurus rex
ontogenesis
allometry
Źródło:
Acta Palaeontologica Polonica; 2022, 67, 3; 601-615
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An articulated pes from a small parvicursorine alvarezsauroid dinosaur from Inner Mongolia, China
Autorzy:
Hone, D.W.E.
Choiniere, J.N.
Tan, Q.
Xu, X.
Powiązania:
https://bibliotekanauki.pl/articles/21549.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
Dinosauria
Theropoda
maniraptoran
arctometatarsalian organism
Cretaceous
Inner Mongolia
alvarezsauroid dinosaur
dinosaur
China
Opis:
A near complete and articulated parvicursorine pes from the Campanian Wulansuhai Formation is described. This pes is referred to the genus Linhenykus and is one of the first foot skeletons to be described for a derived alvarezsaur, providing new information on the first digit of the pes. The evolution of a laterally directed flange of the anterior face of the distal third metatarsal in arctometatarsalian taxa is described and discussed. This flange may have increased stability of the foot during cursorial locomotion and may also provide useful taxonomic and systematic data.
Źródło:
Acta Palaeontologica Polonica; 2013, 58, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An enigmatic theropod Cryolophosaurus: reviews and comments on its paleobiology
Autorzy:
Yun, Changyu
Powiązania:
https://bibliotekanauki.pl/articles/2060953.pdf
Data publikacji:
2019
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Cryolophosaurus
dinosauria
theropoda
ecology
Antarctica
kriolofozaur
dinozaury
teropod
ekologia
Antarktyda
Opis:
Cryolophosaurus is a genus of theropod dinosaur that is characterized by its distinctive crest formed by dorsally expanded lacrimals. Although its fossils are rare, currently recognized materials suggest this taxon was the largest predator in the Early Jurassic times in Antarctica, indicating it was the apex predator in its ecosystem. The skeleton of Cryolophosaurus bears both advanced and basal characteristics of theropods, making its position within theropod phylogenetic tree controversial. Its unusual anatomical features, size, and the habitat located close to the Jurassic polar circle all differ from other Early Jurassic theropods, indicating it was one of the most ecologically significant taxon of all theropods.
Źródło:
Volumina Jurassica; 2019, 17, 1; 103--110
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An unusual theropod dinosaur from the Late Cretaceous Nemegt Formation of Mongolia
Autorzy:
Osmolska, H
Powiązania:
https://bibliotekanauki.pl/articles/22126.pdf
Data publikacji:
1996
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Theropoda
Mongolia
gady kopalne
skamienialosci
kosci
Bagaraatan ostromi
dinozaury
paleontologia
paleozoologia
Kotlina Nemegt
anatomia zwierzat
Opis:
An incomplete skeleton of a theropod dinosaur, Bagaraatan ostromi gen, et sp. n., was found in the Nemegt Fm. at Nemegt, Mongolia. The mandible in B. ostromi has a shallow but massive dentary, relatively deep postdentary portion with two surangular foramina and somewhat elongated retroarticular process; on the lateral surface of the postacetabular process of the ilium there are two large depressions for muscle origins separated by a crestlike projection; the fibula is fused distally with the tibiotarsus and the coalesced astragalocalcaneum. Bagaraatan represents the Tetanurae and displays some synapomorphies with the Avetheropoda, however, incompleteness of the skeleton of B. ostromi does not allow to determine its more precise affiliation. Bagaraatan was about 3.0-3.5 m long, had a relatively small head and slender hind limbs. The presence of strongly developed hyposphenes in a long series of anterior caudals rendered its tail only slighily flexible proximally.
W pracy opisano nowego mięsożernego dinozaura Bagaraatan ostromi gen. et sp. n. (Theropoda). Okaz obejmujący żuchwę, serię 25 kręgów ogonowych, fragmenty kości miednicy oraz kończyny tylnej, został znaleziony w osadach formacji Nemegt (?środkowy mastrycht) Kotliny Nemegt (Pustynia Gobi, Mongolia) przez Polsko-Mongolską Ekspedycję Paleontologiczną, w l970 roku. Zachowane szczątki świadczą, że B. ostromi był teropodem ok. 3.0-3.5 m długim, o smukłych kończynach tylnych i usztywnionym ogonie. Długość żuchwy wskazuje, że czaszka była stosunkowo niewielka. Żuchwa jest masywna i zaopatrzona była w silne zęby, z których zachowały się tylko korzenie i podstawy koron. Jej część tylna jest dość wysoka i przypomina żuchwy teropodów zaliczanych do polifiletycznej grupy „Carnosauria”, różni się jednak od nich bardziej wydłużonym wyrostkiem pozastawowym i dwoma, zamiast jednego, otworami w kości nadkątowej. W odróżnieniu od większości znanych teropodów, u których najwyżej tylko kilka przednich kręgów ogonowych wykazuje obecność dodatkowych wyrostków (hyposfenów) wzmacniających połączenia międzykręgowe, u B. ostromi wyrostki te występują między kilkunastoma proksymalnymi kręgami ogonowymi, co ograniczało ruchomość ogona także w tym odcinku. Kość biodrowa B. ostromi wyróżnia się obecnością dwóch zagłębień na bocznej stronie wyrostka zapanewkowego, zapewne dla przyczepu bardzo silnego mięśnia biodrowo-udowego. Takie zagłębienia nie są znane u żadnych innych dinozaurów. W budowie podudzia zwraca uwagę częściowy zrost kości piszczelowej i strzałkowej ze sobą oraz z proksymalnym rzędem kości stępu. Zrost tych kości spotykany jest tylko w jednej, prymitywnej grupie teropodów, Ceratosauria, od której jednak B. ostromi różni się szeregiem zaawansowanych cech. Fragmentaryczność materiału, a zwłaszcza brak czaszki i kończyn przednich, sprawiają trudność w zaliczeniu Bagaraatan do jednej ze znanych jednostek taksonomicznych w obrębie Theropoda. Jednak pewne cechy diagnostyczne wskazują, że rodzaj ten jest przedstawicielem Tetanurae Gauthier 1986 i jest najbliżej spokrewniony z Avetheropoda Paul 1988, aczkolwiek jest od nich prymitywniejszy.
Źródło:
Acta Palaeontologica Polonica; 1996, 41, 1; 1-38
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Avialan status for Oviraptorosauria
Autorzy:
Maryanska, T
Osmolska, H.
Wolsan, M.
Powiązania:
https://bibliotekanauki.pl/articles/23106.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
bird
Avialae
phylogenetic analysis
Cretaceous
phylogenetic nomenclature
Theropoda
Dinosauria
dinosaur
Oviraptorosauria
paleontology
Opis:
Oviraptorosauria is a clade of Cretaceous theropod dinosaurs of uncertain affinities within Maniraptoriformes. All previous phylogenetic analyses placed oviraptorosaurs outside a close relationship to birds (Avialae), recognizing Dromaeosauridae or Troodontidae, or a clade containing these two taxa (Deinonychosauria), as sister taxon to birds. Here we present the results of a phylogenetic analysis using 195 characters scored for four outgroup and 13 maniraptoriform (ingroup) terminal taxa, including new data on oviraptorids. This analysis places Oviraptorosauria within Avialae, in a sister−group relationship with Confuciusornis. Archaeopteryx, Therizinosauria, Dromaeosauridae, and Ornithomimosauria are successively more distant outgroups to the Confuciusornis−oviraptorosaur clade. Avimimus and Caudipteryx are successively more closely related to Oviraptoroidea, which contains the sister taxa Caenagnathidae and Oviraptoridae. Within Oviraptoridae, “Oviraptor” mongoliensis and Oviraptor philoceratops are successively more closely related to the Conchoraptor−Ingenia clade. Oviraptorosaurs are hypothesized to be secondarily flightless. Emended phylogenetic definitions are provided for Oviraptoridae, Caenagnathidae, Oviraptoroidea, Oviraptorosauria, Avialae, Eumaniraptora, Maniraptora, and Maniraptoriformes.
Źródło:
Acta Palaeontologica Polonica; 2002, 47, 1
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:
Caudipteryx as a non-avalian theropod rather than a flightless bird
Autorzy:
Dyke, G J
Norell, M.A.
Powiązania:
https://bibliotekanauki.pl/articles/22434.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
bird
Avialae
feather
Cretaceous
Caudipteryx zoui
China
Theropoda
Dinosauria
Yixian Formation
paleontology
Opis:
Caudipteryx zoui is a small enigmatic theropod known from the Early Cretaceous Yixian Formation of the People’s Republic of China. From the time of its initial description, this taxon has stimulated a great deal of ongoing debate regarding the phylogenetic relationship between non−avialan theropods and birds (Avialae) because it preserves structures that have been uncontroversially accepted as feathers (albeit aerodynamically unsuitable for flight). However, it has also been proposed that both the relative proportions of the hind limb bones (when compared with overall leg length), and the position of the center of mass in Caudipteryx are more similar to those seen in extant cusorial birds than they are to other non−avialan theropod dinosaurs. This conclusion has been used to imply that Caudipteryx may not have been correctly interpreted as a feathered non−avialan theropod, but instead that this taxon represents some kind of flightless bird. We review the evidence for this claim at the level of both the included fossil specimen data, and in terms of the validity of the results presented. There is no reason—phylogenetic, morphometric or otherwise—to conclude that Caudipteryx is anything other than a small non−avialan theropod dinosaur.
Źródło:
Acta Palaeontologica Polonica; 2005, 50, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada
Autorzy:
Currie, P J
Powiązania:
https://bibliotekanauki.pl/articles/20676.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Late Cretaceous
Cretaceous
Canada
Theropoda
dinosaur
Alberta
Saurischia
Coelurosauria
anatomy
Dinosauria
Tyrannosauridae
skull
paleontology
tyrannosaurid dinosaur
Opis:
Beautifully preserved, nearly complete theropod skeletons from Alberta (Canada) allow re−evaluation of the taxonomic status of North American tyrannosaurids. It is concluded that the most parsimonious interpretation of relationships leads to the separation of the two species of Albertosaurus(sensu Russell 1970) into Gorgosaurus libratusfrom the Campanian Dinosaur Park Formation and Albertosaurus sarcophagus from the upper Campanian/lower Maastrichtian Horseshoe Canyon Formation. Albertosaurus and Gorgosaurus are closely related, but can be distinguished from each other by more characters than are known to justify generic distinction within another tyrannosaurid clade that includes Daspletosaurus, Tarbosaurus and Tyrannosaurus. Daspletosaurus is known from multiple species that cover extensive geographic, ecological and temporal ranges, and it is sensible to maintain its generic distinction from Tyrannosaurus. All tyrannosaurid species have consistent ontogenetic trends. However, one needs to be cautious in assessing ontogenetic stage because many characters are size−dependent rather than age−dependent. There are relatively few osteological differences that can distinguish tyrannosaurid species at any age. For example, Nanotyrannus lancensis is probably a distinct species from Tyrannosaurus rex because there is no evidence of ontogenetic reduction of tooth counts in any other tyrannosaurid species. Some characters that are good for separating mature tyrannosaurids, such as differences in the sizes and shapes of maxillary fenestrae, are not useful for identifying the species of juveniles.
Źródło:
Acta Palaeontologica Polonica; 2003, 48, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł

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