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The digital Plateosaurus II: An assessment of the range of motion of the limbs and vertebral column and of previous reconstructions using a digital skeletal mount

100%

Mallison H.

Acta Palaeontologica Polonica

2010

tom 55

nr 3

433-458

Scientific literature and museum exhibits are full of explicit and implicit claims about the possible postures and motion ranges of dinosaurs. For the example of the prosauropod Plateosaurus engelhardti I assessed the motion range of limbs and vertebral column in a CAD program using a 3D virtual skeletal mount. The range of motion of the forelimb is very limited, allowing the grasping of objects placed directly ventrally and ventrolaterally of the anterior torso. The manus is adapted for grasping. The powerful fore limb can barely reach in front of the shoulder, making a quadrupedal walking cycle impractical. Only a digitigrade pose of the pes with a steeply held metatarsus is feasible, and the morphology of the stylopodium and zeugopodium indicates a slightly flexed limb posture. Hind limb protraction and retraction are limited by the pelvic architecture. The neck has significant mobility both dorsoventrally and laterally, but blocks torsion. The dorsal vertebral column is flexible to a degree similar to the neck, mainly in the anterior half, but blocks torsion totally in the anterior and posterior thirds. The anterior dorsals are similar in shape to the posterior cervicals and significantly increase the motion range of the neck. The tail is highly flexible due to its large number of elements, showing more lateral than dorsoventral mobility. These results are compared to reconstruction drawings and museum skeletal mounts, highlighting a pattern of errors specific to certain widely used reconstruction methods.

Anatomy of a basal sauropodomorph dinosaur from the Early Jurassic Hanson Formation of Antarctica

100%

Smith N. D., Pol D.

Acta Palaeontologica Polonica

2007

tom 52

nr 4

The anatomy of a basal sauropodomorph (Dinosauria: Saurischia) from the Early Jurassic Hanson Formation of Antarctica is described in detail. The material includes a distal left femur and an articulated right pes, including the astragalus, distal tarsals, and metatarsals I–IV. The material is referable to Sauropodomorpha and represents a noneusauropod, sauropodomorph more derived than the most basal members of Sauropodomorpha (e.g., Saturnalia, Thecodontosaurus, Efraasia, and Plateosaurus) based on a combination of plesiomorphic and derived character states. Several autapomorphies present in both the femur and metatarsus suggest that this material represents a distinct sauropodomorph taxon, herein named Glacialisaurus hammeri gen. et sp. nov. Some of the derived characters present in the Antarctic taxon suggest affinities with Coloradisaurus and Lufengosaurus (e.g., proximolateral flange on plantar surface of metatarsal II, well−developed facet on metatarsal II for articulation with medial distal tarsal, subtrapezoidal proximal surface of metatarsal III). Preliminary phylogenetic analyses suggest a close relationship between the new Antarctic taxon and Lufengosaurus from the Early Jurassic Lufeng Formation of China. However, the lack of robust support for the taxon’s phylogenetic position, and current debate in basal sauropodomorph phylogenetics limits phylogenetic and biogeographic inferences drawn from this analysis. The new taxon is important for establishing the Antarctic continent as part of the geographic distribution of sauropodomorph dinosaurs in the Early Jurassic, and recently recovered material from the Hanson Formation that may represent a true sauropod, lends support to the notion that the earliest sauropods coexisted with their basal sauropodomorph relatives for an extended period of time.

Ograniczanie wyników

2 Acta Palaeontologica Polonica

1 Mallison H.

1 Pol D.

1 Smith N. D.

1 2010

1 2007

Wyniki wyszukiwania

The digital Plateosaurus II: An assessment of the range of motion of the limbs and vertebral column and of previous reconstructions using a digital skeletal mount

Anatomy of a basal sauropodomorph dinosaur from the Early Jurassic Hanson Formation of Antarctica