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Tytuł:
New sauropod trackways from the Middle Jurassic of Portugal
Autorzy:
Santos, V F
Moratalla, J.J.
Royo-Torres, R.
Powiązania:
https://bibliotekanauki.pl/articles/22749.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
new sauropod
sauropod
paleontology
trackway
Middle Jurassic
Jurassic
Portugal
Dinosauria
Sauropoda
morphotype
Opis:
The Galinha tracksite reveals a sequence of Bajocian–Bathonian limestones belonging to the Serra de Aire Formation (West−Central Portugal) and is one of the few sites in the world where Middle Jurassic sauropod dinosaur tracks can be found. This tracksite is characterised by the presence of long, wide gauge sauropod trackways, the Middle Jurassic age of which suggests these dinosaurs were more widely distributed over time than previously thought. Two trackways contain unique pes and manus prints with morphologies that allow a new sauropod ichnotaxon to be described: Polyonyx gomesi igen. et isp. nov. On the basis of different manus/pes prints and trackway features, the proposal is made to subdivide Sauropodomorpha ichno−morphotypes into five groups: Tetrasauropus−like, Otozoum−like, Breviparopus/Parabrontopodus−like; Brontopodus−like, and Polyonyx−like. Polyonyx gomesi igen. et isp. nov. is thought to represent a nonneosauropod eusauropod, with a well developed manus digit I. The posterior orientation of this digit print suggests they were made by a eusauropod dinosaur with a posteriorly rotated pollex. The manus print morphologies observed in two trackways suggest a stage of manus structure intermediate between the primitive non−tubular sauropod manus and the tubular metacarpal arrangement characteristic of more derived sauropods. The low heteropody (manus:pes area ratio 1:2) of the trackway renders it possible they could have been made by eusauropods such as Turiasaurus riodevensis, which has a similar manus:pes area ratio. The Polyonyx igen. nov. trackway was made by non−neosauropod eusauropod, and suggests that wide gauge sauropod trackways were not exclusively made by Titanosauriformes.
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 3; 409-422
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The appendicular skeleton of Neuquensaurus, a Late Cretaceous saltasaurine sauropod from Patagonia, Argentina
Autorzy:
Otero, A
Powiązania:
https://bibliotekanauki.pl/articles/22709.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
appendicular skeleton
skeleton
paleontology
Neuquensaurus
Late Cretaceous
saltasaurine sauropod
sauropod
Patagonia
Argentina
Sauropoda
Saltasaurinae
Neuquensaurus australis
Neuquensaurus robustus
anatomy
Cretaceous
sauropod evolution
Opis:
Neuquensaurus, from the Late Cretaceous of Argentina and one of the first dinosaurs described from Patagonia, is one of the most derived sauropod dinosaurs, and its proportions and size place it among the smallest sauropods ever known. In this context, Neuquensaurus is central to understanding late stages of sauropod evolution. This contribution offers a full description of the appendicular skeleton of Neuquensaurus. The anatomical analysis reveals that the appendicular skeleton of Neuquensaurus exhibits unique characteristics only shared with closely related saltasaurine titanosaurs; for example, the laterally directed preacetabular lobe of the ilium, the prominent fibular lateral tuberosity, and the presence of an intermuscular line on the femoral shaft, which is proposed here as a synapomorphy of Saltasaurinae. Neuquensaurus also displays many reversals to primitive character states, such as the presence of a prominent olecranon process of the ulna, a trochanteric shelf, a lesser trochanter and an ischial tuberosity. Additional characters that allow its evaluation in a phylogenetic context are here provided. Among them are the extremely deflected femoral shaft, the elliptical femoral cross−section, and the anterolaterally oriented cnemial crest.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 3; 399-426
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pneumaticity and soft-tissue reconstructions in the neck of diplodocid and dicraeosaurid sauropods
Autorzy:
Schwarz, D
Frey, E.
Meyer, C.A.
Powiązania:
https://bibliotekanauki.pl/articles/22875.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Dicraeosauridae
pneumaticity
cervical ligament
morphology
dicraeosaurid sauropod
diplodocid sauropod
sauropod
Diplodocidae
body length
muscle
ontogenesis
tomography
soft tissue reconstruction
cervical musculature
vertebral pneumaticity
paleontology
functional morphology
Opis:
The axial soft−tissue system in the neck of Dicraeosauridae and Diplodocidae, including pneumatic diverticula, ligaments, and muscles, is reconstructed on the basis of phylogenetic and functional morphological comparisons with extant crocodylians and birds and compared with other soft−tissue reconstructions for sauropods. Bifurcation of the neural spines separated the paired supraspinal ligament into two sheets. A paired interspinal septum was attached to the cranial and caudal margins of the neural spines. The dorsal and the lateral portions of the cervical musculature must have been strongly segmented, whereas the laterocostal portion was divided with one myoseptum per vertebral segment. The hypaxial cervical muscle was most probably small and only poorly segmented. In Diplodocidae and Dicraeosauridae, the distribution of external pneumatic structures is similar, whereas only Diplodocidae possess intraosseous pneumatic structures. Supravertebral pneumatic diverticula are reconstructed for both groups, which, together with dorsal ligaments filled the gap between the metapophyses of bifurcate neural spines. Comparisons between the vertebrae of juvenile and adult diplodocids strongly indicate that pneumatisation proceeded from the supramedullary diverticula into the neural arch and the neural spine. The regular branching pattern of the pneumatic cavities as well as the vertical I−beam construction of the vertebral corpora is interpreted as a consequence of the biomechanical constraints of the vertebral corpora in diplodocids. These reconstructions form the ground for functional morphological considerations in Diplodocidae and Dicraeosauridae while addressing the possible mechanical consequences of pneumatic structures for the integrity of the support system of the neck.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Demandasaurus darwini, a new rebbachisaurid sauropod from the Early Cretaceous of the Iberian Peninsula
Autorzy:
Fernandez-Baldor, F.T.
Canudo, J.I.
Huerta, P.
Montero, D.
Pereda Suberbiola, X.
Salgado, L.
Powiązania:
https://bibliotekanauki.pl/articles/22403.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Demandasaurus darwini
new species
rebbachisaurid sauropod
sauropod
paleontology
Early Cretaceous
Cretaceous
Iberian Peninsula
Spain
Sauropoda
Rebbachisauridae
systematics
paleobiogeography
Opis:
A new medium−sized rebbachisaurid sauropod from the Castrillo la Reina Formation (Upper Barremian–Lower Aptian) in Burgos Province, Demandasaurus darwini gen. et sp. nov., is described. It is known from an incomplete but associated skeleton that includes cranial and post−cranial remains. Demandasaurus darwini gen. et sp. nov. presents 9 autapomorphies in the teeth and vertebrae. Demandasaurus is the first diplodocoid sauropod described from the Cretaceous of the Iberian Peninsula. Its inclusion in the Rebbachisauridae is well supported by our phylogenetic hypothesis, which situates it as a sister group of Nigersaurus from the Aptian of Niger, with which it shares various synapomorphies. The discovery of Demandasaurus provides further evidence of the sporadic use of the Apulian Route by dinosaurs during the Early Cretaceous for moving between the south of Europe (Laurasia) and the north of Africa (Gondwana).
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Braincase anatomy of the titanosaurian sauropod Lirainosaurus astibiae from the Late Cretaceous of the Iberian Peninsula
Autorzy:
Diez Diaz, V.
Pereda Suberbiola, X.
Sanz, J.L.
Powiązania:
https://bibliotekanauki.pl/articles/22340.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
braincase zob.neurocranium
neurocranium
anatomy
titanosaurian sauropod
Lirainosaurus astibiae
Late Cretaceous
Cretaceous
Iberian Peninsula
paleontology
Sauropoda
Titanosauria
Lirainosaurus
Europe
sauropod
Opis:
Lirainosaurus is the only titanosaurian sauropod described to date from the Late Cretaceous of the Iberian Peninsula. The type of Lirainosaurus astibiae consists of both cranial and postcranial remains that were found as disarticulated elements in the Laño quarry (Treviño, northern Spain). This taxon was diagnosed originally on the basis of vertebral and appendicular autapomorphic traits. The study of a paratypic skull fragment and a second referred specimen provides information about its braincase morphology. Lirainosaurus is regarded as a derived titanosaur on the basis of the complete fusion between the prootic and the exoccipital−opisthotic complex, the position of the cranial foramina, and the shape and orientation of the occipital condyle. The braincase of L. astibiae appears to be diagnostic in the presence of a foramen distally on each basal tubera. The absence of median subcondylar foramina in the basioccipital may be an autopomorphic trait or be due to ontogenetic growth. A comparison with other partial skulls known in Europe suggests a high diversity during the Campanian/Maastrichtian, with at least three different titanosaurian species living in the Ibero−Armorican Island.
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 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:
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:
A new sauropod dinosaur from the Lower Cretaceous Cedar Mountain Formation, Utah, USA
Autorzy:
Taylor, M.
Wedel, M.
Cifelli, R.
Powiązania:
https://bibliotekanauki.pl/articles/23198.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
Dinosauria
Sauropoda
Camarasauromorpha
Brontomerus
Brontomerus mcintoshi
diversity
Early Cretaceous
North America
new sauropod dinosaur
Lower Cretaceous
Cedar Mountain Formation
Utah
Cretaceous
sauropod dinosaur
Opis:
Brontomerus mcintoshi is a new genus and species of sauropod dinosaur from the Hotel Mesa Quarry in Grand County, Utah, USA, in the upper part of the Ruby Ranch Member (Aptian–Albian) of the Lower Cretaceous Cedar Mountain Formation. It is known from at least two fragmentary specimens of different sizes. The type specimen is OMNH 66430, the left ilium of a juvenile individual; tentatively referred specimens include a crushed presacral centrum, a complete and well−preserved mid−to−posterior caudal vertebra, the partial centrum of a distal caudal vertebra, a complete pneumatic anterior dorsal rib from the right side, the nearly complete left scapula of a much larger, presumably adult, individual, and two partial sternal plates. Brontomerus is diagnosed by five autapomorphies of the type specimen: preacetabular lobe 55% of total ilium length, longer than in any other sauropod; preacetabular lobe directed anterolaterally at 30 to the sagittal, but straight in dorsal view and vertically oriented; postacetabular lobe reduced to near absence; ischiadic peduncle reduced to very low bulge; ilium proportionally taller than in any other sauropod, 52% as high as long. In a phylogenetic analysis, Brontomerus was recovered as a camarasauromorph in all most parsimonious trees, but with uncertain position within that clade. The large preacetabular lobe of the ilium anchored powerful protractor and abductor muscles, but precise interpretation is impossible without functionally related elements such as femora and proximal caudal vertebrae. Brontomerus is the eighth sauropod genus named from the Early Cretaceous of North America, and more remain to be described: North American sauropod diversity did not decline catastrophically at the end of the Jurassic as often assumed. The most striking differences between Late Jurassic and Early Cretaceous sauropod faunas in North America is that the former are abundant and dominated by diplodocids, whereas the latter are comparatively scarce— though still diverse—and dominated by macronarians.
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Speeds of dinosaurs from the Albian-Cenomanian of Patagonia and sauropod stance and gait
Autorzy:
Mazzetta, G V
Blanco, R E
Powiązania:
https://bibliotekanauki.pl/articles/20359.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleoichnology
dinosaur speed
Rio Limay Formation
gait
Patagonia
dinosaur
sauropod stance
Opis:
Estimates of locomotory speeds of small to large-sized Patagonian dinosaurs are presented for the first time. These estimates are inferred from trackways found on fine to coarse-grained brown sandstones located in the lower section of the Candeleros Member of the Río Limay Formation (Albian-Cenomanian), Neuquén Province, Argentina. The method used is based on the measurement of the stride length (distance between two successive prints of the same foot) and of the length of the hindfoot print, which in turn, allows us to estimate the height at the hip joint and, therefore, the approximate size of the animal. The hypothesis of dynamic similarity implies that the movements of geometrically similar animals, although of different sizes, are dynamically similar only when they move with the same Froude number. The dynamically similar movements (i.e., those with equal Froude number) require equal values of relative stride length (ratio between the stride length and the hip joint height). The relationship between the relative stride length and the Froude number allows us to estimate the speeds of dinosaurs. The dinosaurian ichnofauna studied reveals low speeds that range from 0.5 to 2.6 m s⁻¹. Our analyses show that the sauropods responsible for these trackways were either walking very slowly in a bipedal stance or alternatively they were progressing quadrupedally on a slippery surface.
Źródło:
Acta Palaeontologica Polonica; 2001, 46, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A sauropod foot from the Early Cretaceous of Western Siberia, Russia
Autorzy:
Averianov, A O
Voronkevich, A.V.
Maschenko, E.N.
Leshchinskiy, S.V.
Fayngertz, A.V.
Powiązania:
https://bibliotekanauki.pl/articles/20801.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Ilek Formation
Titanosauriformes
Cretaceous
Russia
Siberia
Sauropoda
sauropod foot
paleontology
postcranial skeleton
Opis:
We describe a reasonably complete sauropod foot from the Early Cretaceous (Aptian–Albian) Ilek Formation at the Shestakovo locality in Western Siberia, Russia.It shows some primitive characters, such as slender metatarsals, a relatively long second pedal ungual, and three claws.In the likely presence of the laterodistal process on the first metatarsal the Shestakovo sauropod is similar with diplodocoids, but its more elongated and gracile first metatarsal resembles brachiosaurids (Brachiosaurus, Pleurocoelus, and Cedarosaurus), titanosaurids (Laplatasaurus), and Euhelopus. Pleurocoelus−like isolated teeth from the Shestakovo assemblage may support the brachiosaurid affinities of the Shestakovo sauropod, but a strongly procoelous mid−caudal vertebra from another locality in the same formation establishes the presence of a titanosaurid in the fauna.The foot described is referred here to as Titanosauriformes gen.et sp.indet.
Źródło:
Acta Palaeontologica Polonica; 2002, 47, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Head and neck posture in sauropod dinosaurs inferred from extant animals
Autorzy:
Taylor, M P
Wedel, M.J.
Naish, D.
Powiązania:
https://bibliotekanauki.pl/articles/22737.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
dinosaur
sauropod dinosaur
extant animal
head posture
neck posture
Dinosauria
Sauropoda
Opis:
The neck posture of sauropod dinosaurs has long been controversial. Recent reconstructions position the cervical vertebrae and skull in an “osteological neutral pose” (ONP), the best fit arrived at by articulating the vertebrae with the zygapophyses in maximum contact. This approach in isolation suggests that most or all sauropods held their necks horizontally. However, a substantial literature on extant amniotes (mammals, turtles, squamates, crocodilians and birds) shows that living animals do not habitually maintain their necks in ONP. Instead, the neck is maximally extended and the head is maximally flexed, so that the mid−cervical region is near vertical. Unless sauropods behaved differently from all extant amniote groups, they must have habitually held their necks extended and their heads flexed. The life orientation of the heads of sauropods has been inferred from the inclination of the semi−circular canals. However, extant animals show wide variation in inclination of the “horizontal” semi−circular canal: the orientation of this structure is not tightly constrained and can give only a general idea of the life posture of extinct animals’ heads.
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 2; 213-220
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A monument of inefficiency: The presumed course of the recurrent laryngeal nerve in sauropod dinosaurs
Autorzy:
Wedel, M.J.
Powiązania:
https://bibliotekanauki.pl/articles/23398.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
laryngeal nerve
sauropod dinosaur
dinosaur
Dinosauria
Sauropoda
larynx
neck
neuron
paleontology
life history
Opis:
The recurrent laryngeal nerve is an often cited example of “unintelligent design” in biology, especially in the giraffe. The nerve appears early in embryonic development, before the pharyngeal and aortic arches are separated by the development of the neck. The recurrent course of the nerve from the brain, around the great vessels, to the larynx, is shared by all extant tetrapods. Therefore we may infer that the recurrent laryngeal nerve was present in extinct tetrapods, had the same developmental origin, and followed the same course. The longest−necked animals of all time were the extinct sauropod dinosaurs, some of which had necks 14 meters long. In these animals, the neurons that comprised the recurrent laryngeal nerve were at least 28 meters long. Still longer neurons may have spanned the distance from the end of the tail to the brainstem, as in all extant vertebrates. In the longest sauropods these neurons may have been 40–50 meters long, probably the longest cells in the history of life.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evidence for a sauropod-like metacarpal configuration in stegosaurian dinosaur
Autorzy:
Senter, P
Powiązania:
https://bibliotekanauki.pl/articles/23329.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
evidence
paleontology
sauropod
metacarpal configuration
stegosaurian dinosaur
dinosaur
Dinosauria
Ornithischia
Stegosauria
forelimb
functional morphology
Opis:
The stegosaurian forelimb is usually portrayed with the metacarpals slanted and distally spread. However, manual manipulation of stegosaurian metacarpals reveals that in that configuration they do not articulate with each other nor with the rest of the forelimb. Rather, they do articulate with each other and with the rest of the forelimb when posed vertically and arranged in a compact, semi−tubular configuration, as in sauropods. This configuration agrees with data from articulated specimens and trackways. As with sauropods, this metacarpal configuration makes retention of phalanges awkward for locomotion and may be functionally related to the vestigiality of the manual phalanges of the outer digits.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 3; 427-432
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Osteology, paleobiology, and relationships of the sauropod dinosaur Sauroposeidon
Autorzy:
Wedel, M J
Cifelli, R L
Sanders, R K
Powiązania:
https://bibliotekanauki.pl/articles/22230.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Oklahoma
pneumatic structure
Sauroposeidon proteles
Sauroposeidon
paleobiology
Cretaceous
Antlers Formation
dinosaur
sauropod
North America
paleontology
Opis:
Sauroposeidon proteles is a large brachiosaurid sauropod recently described from the Antlers Formation (Aptian-Albian) of southeastern Oklahoma. Sauroposeidon represents the culmination of brachiosaurid trends toward lengthening and lightening the neck, and its cervical vertebrae are characterized by extensive pneumatic structures. The elaboration of vertebral air sacs during sauropod evolution produced a variety of internal structure types. We propose a new classification system for this array of vertebral characters, using computed tomography (CT) of pneumatic internal structures. Comparisons with birds suggest that the vertebrae of sauropods were pneumatized by a complex system of air sacs in the thorax and abdomen. The presence of a thoraco-abdominal air sac system in sauropods would dramatically affect current estimates of mass, food intake, and respiratory requirements. Sauroposeidon was one of the last sauropods in the Early Cretaceous of North America; sauropods disappeared from the continent by the early Cenomanian. The demise of sauropods in the Early Cretaceous of North America predates significant radiations of angiosperms, so the decline and extinction of this dinosaur group cannot be linked to changes in flora.
Sauroposeidon proteles to wielki dinozaur z rodziny brachiozaurów, opisany niedawno z formacji Antlers (apt-alb) z południowo-wschodniej Oklahomy (USA). Stanowi on kulminację widocznej u brachiozaurów tendencji do wydłużania szyi i zmniejszania jej ciężaru - kręgi szyjne odznaczają się intensywną pneumatyzacją. Rozrost worków powietrznych w kręgach szyjnych doprowadził do wytworzenia rozmaitych wariantów ich budowy wewnętrznej. Autorzy proponują nowy podział owych struktur anatomicznych, oparty na obserwacji tomograficznej spneumatyzowanych kręgów. Porównania z ptakami sugerują, że kręgi zauropodów mieściły rozbudowany system worków powietrznych obejmujących też tułów. Obecność piersiowo-brzusznych worków powietrznych oznaczałaby radykalne zmiany dotychczasowych oszacowań masy ciała, zapotrzebowania pokarmowego i wydolności oddechowej zauropodów. Zauroposejdon był jednym z ostatnich zauropodów zamieszkujących Amerykę Północną we wczesnej kredzie (we wczesnym cenomanie brak już zauropodów na tym kontynencie). Zniknięcie zauropodów z Ameryki Północnej poprzedziło większe radiacje adaptacyjne roślin okrytozalążkowych, toteż nie można wiąać upadku i zaniku tej grupy dinozaurów ze zmianami flory.
Źródło:
Acta Palaeontologica Polonica; 2000, 45, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three-dimensional elasto-plastic soil modelling and analysis of sauropod tracks
Autorzy:
Sanz, E.
Arcos, A.
Pascual, C.
Pidal, I.M.
Powiązania:
https://bibliotekanauki.pl/articles/21227.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Sauropoda
ichnology
3D analysis
mathematical simulation
elasto-plastic model
soil mechanics
Spain
soil
modelling
sauropod
Opis:
This paper reports the use of FEA (Finite Element Analysis) to model dinosaur tracks. Satisfactory reproductions of sauropod ichnites were simulated using 3D numerical models of the elasto-plastic behaviour of soils. Though the modelling was done of ichnites in situ at the Miraflores I tracksite (Soria, Spain), the methodology could be applied to other tracksites to improve their ichnological interpretation and better understand how the type and state of the trodden sediment at the moment the track is created is a fundamental determinant of the morphology of the ichnite. The results obtained explain why the initial and commonly adopted hypothesis—that soft sediments become progressively more rigid and resistant at depth—is not appropriate at this tracksite. We explain why it is essential to consider a more rigid superficial layer (caused by desiccation) overlying a softer layer that is extruded to form a displacement rim. Adult sauropods left trackways behind them. These tracks could be filled up with water due to phreatic level was close to the ground surface. The simulation provides us with a means to explain the differences between similar tracks (of different depths; with or without displacement rims) in the various stratigraphic layers of the tracksite and to explain why temporary and variable conditions of humidity lead to these differences in the tracks. The simulations also demonstrate that track depth alone is insufficient to differentiate true tracks from undertracks and that other discrimination criteria need to be taken into account. The scarcity of baby sauropod tracks is explained because they are shallow and easily eroded.
Źródło:
Acta Palaeontologica Polonica; 2016, 61, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł

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