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Wyświetlanie 1-3 z 3
Tytuł:
New skulls of the basal sauropodomorph Plateosaurus trossingensis from Frick, Switzerland: Is there more than one species?
Autorzy:
Lallensack, J.N.
Teschner, E.M.
Pabst, B.
Sander, M.
Powiązania:
https://bibliotekanauki.pl/articles/2082289.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Dinosauria
Sauropodomorpha
Plateosaurus
ontogeny
intraspecific variability
preservation
skull anatomy
Triassic
Switzerland
Opis:
The Triassic basal sauropodomorph Plateosaurus trossingensis is well-known from mass accumulations at the German localities of Trossingen and Halberstadt and the Swiss locality of Frick, and is significant especially regarding its taphonomy and proposed developmental plasticity. These implications, however, rely on the assumption that this material derives from a single species, which has been questioned. Here we describe new skull material from Frick including eight complete and six partial skulls, more than doubling the number of known skulls of P. trossingensis. This exceptional sample size allows for gaining a deeper understanding of variability that may occur in a single species. The new material includes the first known juvenile skulls of Plateosaurus, allowing for detecting ontogenetic changes. An attempt is made to distinguish between variability caused by taphonomic plastic deformation and intraspecific variability. Plastic deformation may shorten, but not widen bones. A number of characters commonly included in phylogenetic analyses of basal sauropodomorphs are shown to be variable within P. trossingensis, and possibly require re-evaluation. Although P. trossingensis skulls are highly variable, many of the variable characters include intermediate character states and therefore are continuous. No groupings based on skull features, locality, or stratigraphy are apparent. Consequently, the analyzed skull material from the bonebeds of Frick, Trossingen, and Halberstadt bears no evidence for the presence of more than one species.
Źródło:
Acta Palaeontologica Polonica; 2021, 66, 1; 1-28
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Postcranial osteology of the first early-stage juvenile skeleton of Plateosaurus trossingensis from the Norian of Frick, Switzerland
Autorzy:
Nau, D.
Lallensack, J.N.
Bachmann, U.
Sander, P.M.
Powiązania:
https://bibliotekanauki.pl/articles/2082237.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Dinosauria
Sauropodomorpha
morphometrics
morphology
small body size
early ontogeny
Triassic
Swiss Plateau
Opis:
Owing to monospecific mass-accumulation sites in Central Europe, the early-branching sauropodomorph Plateosaurus has one of the best fossil records among dinosaurs. Despite this, early-stage juveniles have been conspicuously absent. However, such specimens are critical in assessing the ontogenetic development of this taxon, as well as the role of heterochrony in sauropodomorph evolution. A new skeleton from the Plateosaurus bonebed at the Gruhalde Quarry (Klettgau Formation, Norian) of Frick, Switzerland, nicknamed “Fabian”, represents the first substantially complete juvenile referrable to Plateosaurus. The specimen includes large portions of the cranium and vertebral column and an almost completely represented appendicular skeleton. Its juvenile ontogenetic stage is confirmed by a lack of neurocentral suture fusion in the axial skeleton. Consistent with this, the estimated total length and body mass of approximately of 2.3 m and 40 kg are considerably smaller than any previously reported specimen of the genus. Surprisingly, the postcranial morphology of the specimen is remarkably consistent with that of osteologically mature individuals, including a virtually fully developed pattern of laminae and fossae in the vertebrae. Comparisons of body proportions are complicated by varying degrees of compaction in the limb elements, but skeletal proportions mostly appear to follow isometry, with the notable exceptions of a relatively long neck, proportionately larger manus, shorter, more gracile humerus and shorter forearm in the juvenile specimen. The observed morphology suggests that adult morphology was either achieved early in ontogeny of Plateosaurus, or alternatively that developmental plasticity, which has previously been found to result in high variability of adult body size, could potentially also extend to morphological development.
Źródło:
Acta Palaeontologica Polonica; 2020, 65, 4; 679-708
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The early evolution of postcranial skeletal pneumaticity in sauropodomorph dinosaurs
Autorzy:
Yates, A.M.
Wedel, M.J.
Bonnan, M.F.
Powiązania:
https://bibliotekanauki.pl/articles/21858.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
evolution
postcranial skeletal pneumaticity sauropodomorph dinosaur
dinosaur
Sauropodomorpha
Sauropoda
air sac
Triassic
Jurassic
South Africa
Opis:
Postcranial skeletal pneumaticity (PSP) is present in a range of basal sauropodomorphs spanning the basal sauropodomorph–sauropod transition. We describe the PSP of five taxa, Plateosaurus engelhardti, Eucnemesaurus fortis, Aardonyx celestae, Antetonitrus ingenipes, and an unnamed basal sauropod from Spion Kop, South Africa (hereafter referred to as the Spion Kop sauropod). The PSP of Plateosaurus is apparently sporadic in its occurrence and has only been observed in very few specimens, in which it is of very limited extent, affecting only the posterior cervical vertebrae and possibly the mid dorsals in one specimen. The PSP of Eucnemesaurus, Aardonyx, Antetonitrus, and the Spion Kop sauropod consists of subfossae (fossa−within−fossa structures) that excavate the vertices of the posterior infradiapophyseal fossae of the posterior dorsal vertebrae. These subfossae range from simple shallow depressions (Eucnemesaurus) to deep, steepsided, internally subdivided and asymmetrically developed chambers (Antetonitrus). The middle and anterior dorsal vertebrae of these taxa lack PSP, demonstrating that abdominal air sacs were the source of the invasive diverticula. The presence of pneumatic features within the infradiapophyseal fossae suggest that the homologous fossae of more basal saurischians and dinosauriforms were receptacles that housed pneumatic diverticula. We suggest that it is probable that rigid non−compliant lungs ventilated by compliant posterior air sacs evolved prior to the origination of Dinosauria.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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